Curtiss XP-17

Curtiss XP-17

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Curtiss XP-17

The Curtiss XP-17 was the designation given to the first P-1 when it was used to test a Curtiss Wright Tornado engine. The first P-1 (25-410) was used for tests throughout its career, but kept the P-1 designation until 1930. In that year a 480hp Curtiss V-1470 inverted V-12 engine was installed in the aircraft and it was given the designation XP-17. Tests began in June 1930 and focused on the engine rather than the aircraft itself.

The same aircraft had been used for other engine tests without getting a new designation - in 1926 it had been given an Allison inverted air cooled V-12 and was entered in the 1926 air race, but remained a P-1.

Engine: Curtiss Wright V-1470-3 Tornado inverted air-cooled engine
Power: 480hp
Crew: 1
Span: 31ft 6in
Length: 22ft 10in
Height: 8ft 7in
Empty weight: 2,204lb
Gross weight: 2,994lb
Max speed: 165mph at sea level, 161mph at 5,000ft
Climb Rate: 8 mins to 10,000ft

Curtiss Candy Co., est. 1916

In 1953—right around the same time the vintage Baby Ruth display box in our collection was made—radio host and author Henry J. Taylor went on the air and delivered a stirring speech / eulogy for the man they used to call the “Candy Bar King.” Taylor was a former business associate and longtime friend of Otto Schnering, the late founder and president of Chicago’s Curtiss Candy Company.

In the days after Schnering’s death, most journalists took note of the man’s great business savvy—his shrewd marketing campaigns, the invention of the five-cent candy bar, the wild success of the Baby Ruth brand, and the development of one of the nation’s first truly self-sufficient farm-to-factory operations. For Taylor, though, Schnering was far more than a rock star of capitalism.

Taylor titled his radio address “Integrity: A Mighty Force,” and held up his dearly departed friend Schnering as a shining example of American exceptionalism as it related to personal character, rather than profit making. To communicate his point, he focused primarily on one incident—the financial panic of 1929—and how Schnering piloted his business through its darkest hour.

“I cannot tell you this story in an impersonal way because I lived through it,” Taylor told his listeners, recounting a Curtiss Candy Co. creditors meeting held on May 28, 1929. This was months before the famous stock market crash of Black Tuesday, but immediately after a similarly devastating crash in the world commodity markets. Because Otto Schnering had poured most of his profits right back into the operations of his company, he couldn’t pay his growing debts, and the Curtiss Candy empire was suddenly on the brink of bankruptcy.

“I myself had started a business of my own,” Taylor said, “and eventually sold large quantities of supplies to the Curtiss Candy Company. Almost everything I had was tied up in its integrity. That’s the point—it’s integrity.

The creditors’ meeting was held in the ballroom of Chicago’s Belmont Hotel—on a dull grey afternoon, as ominous outside as in the tense, packed atmosphere of that room.

Schnering was told not to come to that meeting. He was excluded, as was every member of the management team. Told to remain in the nearby main office and await the decision of bankruptcy, they were asked to wait there for news of who would succeed Schnering—take over the business built through a decade by men and women whose very success in increasing the business was about to break them, wash out their money and their hearts, and oust them from their jobs.

Up in the ballroom a decision had been reached by the creditors’ meeting. The machinery would be sold. Dismissal notices would go to all employees. Any remaining debts would be abandoned as worthless. The company was through.

Then an amazing thing happened on the floor of the meeting. A man got up and made a little speech. What he said was not remarkable. The remarkable thing is what happened all over the ballroom.

“The Curtiss business ceases to exist without Otto Schnering and his loyal team,” he said. “Any credit extended was extended to that management, not to some inexperienced committee. I have talked with Otto Schnering on this very day. Schnering said to me, ‘You know we can’t collect the amount due from our customers now. We can’t pay our bills. It may take years to pull through. But if everybody will wait and is willing to help, I can see this awful time through and I’ll dedicate my life to this job.’

“That statement,” the speaker went on, “is enough for me. The integrity of this business is the integrity of the people in it, the integrity of the management. I cast my lot with that integrity and with no other.”

The speaker got no further. There was a rumble across the floor. One man after another called “Order! Order!” Men were standing to speak in every part of the room—to speak up and stand with Otto Schnering and the integrity of the team.

The majority of the creditors voted to let Schnering stay in. It took 12 years to clear away the financial problem. Day by day, month by month, year by year, dollar by dollar. From 8 in the morning until 8 at night—10 at night, 12, 1, 2, 3. No letup, no security for Schnering and his associates. Each day simply meant a chance for those men to take each problem, hour by hour, and see it through. Never was a payroll missed—never a penny defaulted.

. . . The Curtiss Candy Company lived through everything and paid off every debt. The team won. Integrity won out—and nothing else but.”

Taylor went as far as to claim that Otto Schnering had “given his life” to the challenge of serving his clients and employees faithfully, contributing to his relatively early death at the age of 62. With the addition of modern-day cynicism, there is admittedly something instantly suspicious about the notion of a truly self-sacrificing industrialist. But most accounts of Schnering paint at least a broadly similar picture of a decent man—obsessively driven, but decent nonetheless.

The Candy King once described his ongoing goal of making Curtiss “a company with a soul, having the benefits of its employees at heart,” and aside from a few grievances from the teamsters, the thousands of men and women who worked for Schnering over the decades seemed to buy in to his philosophy.

[Curtiss Candy Co. founder Otto Schnering (left) pictured with the ribbons and trophies won by the prize cattle, pigs, and sheep from the Curtiss Farms, northwest of Chicago, c. 1950]

X-plane-o-rama December 6, 2010 12:29 AM Subscribe

The X-planes have a long and storied history. From the original sound barrier breaking X-1, to the original space plane the X-15, the X-series of aircraft have represented the cutting edge of aeronautical innovation for the last 65 years.

Accomplishments of the X-Plane family have been many. The program included: (1) the first aircraft to break the sound barrier (2) the first aircraft to use a variable-sweep-wing in flight (3) the first to fly at altitudes in excess of 30,000, 60,000, and 90,000 m (100,000, 200,000 and 300,000Êft) (4) the first to use exotic alloy metals for primary structure (5) the first to test gimbaled jet and rocket engines (6) the first to use jet-thrust for launch and landing (7) the first to fly three, four, five, and six times the speed of sound (8) the first to test boundary-layer-airflow control theories over an entire wing at transonic speeds (9) the first to successfully complete a 180-degree turn using a post-stall maneuver and (10) the first missile to reach an intercontinental flight range.

There are also several series of X-planes that preceded or paralleled the current X naming scheme.

XA series - Prototype or experimental attack aircraft

XB series - Prototype or experimental bomber aircraft

XF Series - This series covers post-World War II fighter development when the newly independent USAF changed the "P" pursuit designation to "F" for fighter.

XP Series - This series covers fighter development up to the end of World War II.

U.S. Navy "X" designations

Non-"X" designations

" It. uses a hydrazine monopropellant rocket."
posted by clavdivs at 1:30 AM on December 6, 2010

You need to talk to someone in the nuclear submarine arena psycho-alchemy. It'll make the space plane people look a lot more laid back.

"Do they paint them gray?" "I'm not allowed to answer that question."
"Do they really go underwater?" "I'm sorry, that information is classified"
"Is today the sixth?" "I can neither confirm or deny. "

I mean I understand that keeping their location a secret is a big portion of their power as a deterrent and that defense analysis is all about gleaning big secrets from a bunch of little details but there comes a point where you've crossed a line into rampant paranoia.

The preceding was somewhat tongue in cheek for humorous effect. Somewhat."
posted by Kid Charlemagne at 5:05 AM on December 6, 2010

I don't know what this aircraft does to the enemy, but by God it terrifies me.

"The XF-84H was quite possibly the loudest aircraft ever built, earning the nickname "Thunderscreech" as well as the "Mighty Ear Banger". On the ground "run ups", the prototypes could reportedly be heard 25 miles (40 km) away. Unlike standard propellers that turn at subsonic speeds, the outer 24–30 inches of the blades on the XF-84H's propeller traveled faster than the speed of sound even at idle thrust, producing a continuous visible sonic boom that radiated laterally from the propellers for hundreds of yards. The shock wave was actually powerful enough to knock a man down an unfortunate crew chief who was inside a nearby C-47 was severely incapacitated during a 30-minute ground run. Coupled with the already considerable noise from the subsonic aspect of the propeller and the dual jet turbines, the aircraft was notorious for inducing severe nausea and headaches among ground crews. In one report, a Republic engineer suffered a seizure after close range exposure to the shock waves emanating from a powered-up XF-84H."

A project of uncommon fail. Worth reading the whole article.
posted by Devonian at 5:11 AM on December 6, 2010 [6 favorites]

The basic capability of the X37B is to bring a small amount of cargo up and also bring some back down. That second part, also called downmass, is the critical capability that we are losing with the retirement of the shuttle. Without it, we can only bring back from orbit a hundred pounds or so in the Soyuz capsules, basically what they can fit in the returning cosmonauts' laps.

Tomorrow morning, SpaceX will be testing their Falcon 9 / Dragon system for the first time, and that will be the key to restoring downmass capability for the US. You might want to watch NASA TV starting at 9am on Tuesday .
posted by intermod at 5:16 AM on December 6, 2010 [1 favorite]

The "Missing Designations" page is really interesting and something I've always wondered about. (I found it via the X-52 but it may be up there elsewhere)

I also wonder about the ones that don't sound that exciting and have really vague descriptions because we all know what was wedged in between the U-1 and the U-3.
posted by Kid Charlemagne at 5:24 AM on December 6, 2010 [1 favorite]

You've only scratched the surface of Curtiss family history.

Between 1948 and 2004, in the United States, Curtiss life expectancy was at its lowest point in 1957, and highest in 2000. The average life expectancy for Curtiss in 1948 was 51, and 76 in 2004.

An unusually short lifespan might indicate that your Curtiss ancestors lived in harsh conditions. A short lifespan might also indicate health problems that were once prevalent in your family. The SSDI is a searchable database of more than 70 million names. You can find birthdates, death dates, addresses and more.

Curtiss XP-17 - History

The Curtiss Electric Contra-Rotating Propeller System
by Tom Fey
Published 21 Apr 2021

Previous AEHS articles or Convention presentations have described the theory, benefits, and disadvantages of dual rotation propellers. In brief, they offered the potential to absorb several thousand horsepower with reasonable propeller diameters, blade loadings, and tip speeds as well as simplifying the landing gear design requirements to accommodate large diameter propellers. Dual rotation propellers also had the potential to improve propulsion efficiency by 3 to 8% due to the recovery of swirl energy, and improve aircraft handling, especially at low airspeeds, by the elimination of torque. Coaxial propellers, defined as having independent drive and pitch control of two coaxially-located propeller discs, offered twin engine safety with centerline thrust, or enhanced loiter capability using just one engine/propeller. The disadvantages of dual rotation propellers included weight, complexity, noise, vibration, destabilizing side area ahead of the cg in tractor configurations, and specialized production of opposite-rotation components. Previous AEHS publications have covered the design and operation of the de Havilland (2005), Rotol (2008), Aeroproducts (2009), and Hamilton Standard Superhydromatic (2018) contra-rotating propeller (CRP) systems as well as the Curtiss coaxial propeller system (2011).

Fig. 1. The control of propeller pitch for both discs is linked for contra-rotating propellers, but independent for coaxial propellers.

Like Rotol Airscrews of Great Britain, the Propeller Division of the Curtiss-Wright Corporation, Caldwell, New Jersey, produced both coaxial propeller systems (Douglas XB-42) as well as contra-rotating (one power source drives both propellers with linked pitch control and a single propeller governor) propeller systems (Northrop XP-56, Convair XFY-1). (Fig. 1) And again, like Rotol, Curtiss produced CRP units for both piston-powered as well as turboshaft-powered aircraft. The latter systems were incredibly complex units that had to manage 5,000+ horsepower engines running at a constant speed tamed only by integrated fuel controls and propeller pitch change mechanisms. These systems were tasked with keeping engine/propeller speed variations within a few percent (± 8 rpm), regardless of load, accomplished in the bell crank-electro-hydro-mechanical age that preceded Full Authority Digital Engine Control (FADEC). They were masterpieces of engineering.

The Curtiss Electric CRP for piston engines was publicly introduced on October 15, 1942 and USAAF whirl testing began shortly thereafter. (Fig. 2) The Chief Engineer of the Curtiss Propeller Division was George W. Brady who filed a patent for the CRP design in January 1944, granted in December 1950. (Fig. 2a)

To achieve contra-rotating shafts in a geared radial engine, Pratt & Whitney developed a compact assembly that added a Farman bevel gear to the outboard side of the typical planetary gear reduction system. This reversed the rotation of the inboard component but maintained the same rpm on both propeller shafts. (Fig. 3)

The first requirement for a dual-rotation propeller system, either coaxial or contra-rotating, is that the center of the propeller hubs must be hollow to allow the extended shaft that drives the outboard propeller to pass through the center of the inboard propeller hub. For the Allies during WWII, both Curtiss and Aeroproducts produced open-bore propeller systems that were used on the Bell P-39 Airacobra where a 20 mm or 37 mm cannon to fire through the hub of the propeller. This gave these companies a head start on designing dual rotation propeller systems since the actuation system for a hollow-hub propeller was already well established. (Fig. 4)

Fig. 2. November 1942 issue of Bladesman, a monthly publication of the Curtiss-Wright Corporation Propeller Division, announcing the October 15, 1942 introduction of the Curtiss Electric contra-rotating propeller. Fig. 2a. US Patent 2,533,346 for the Dual Rotation Propeller granted to George W. Brady and Charles W. Chillson of Curtiss-Wright Corporation on December 12, 1950. Extensive precision machining and a very high parts count. Fig. 3. Pratt & Whitney Dual Rotation Reduction Gear. The contra-rotating gearbox developed by Pratt &Whitney for use on radial engines used a Farman bevel gear set on the front of a typical planetary reduction gear train. This reversed the direction of rotation of the aft component but maintained the same rpm on each shaft. Engine input is via the sun gear, and this design was used in remote gearboxes for the Northrop XP-56 and XB-35 aircraft. Fig. 4. October 1943 Air Tech Magazine Cover, a USAAF publication, with the Curtiss Electric Model C6315SH hollow bore propeller as used on the P-39 Airacobra.

There were two key mechanical elements to the Curtiss Electric CRP system. The first was the donut-shaped, hollow bore electric motor that provided the motive force for the pitch change system, and second was the Stanley/VDM system of planetary gears that operated with the mandatory open bore and provided the mechanical transmission of a pitch change command from one propeller to a second coaxial propeller rotating in the opposite direction. This system will be described in due course.

The single rotation Curtiss Electric C6315SH (Curtiss 60 spline prop shaft size 3 blade 15 = 1.5 blade socket size Steel blades, Hollow bore) used on the P-39C,-D, -L, and -M used slip rings connected to insulated brass pins situated in hollow hub mounting bolts to transmit either 12 volts (32 amp max) or 24 volts (17 amp max) current to a donut-shaped, 0.5 horsepower, reversible electric motor mounted on the front of the forged steel propeller hub. (Fig. 5) Wired in series with the motor circuit was a solenoid (12V, 35 amp max or 24V, 20 amp max) that withdrew the spring-loaded brake pad from the motor face whenever current was fed to the electric motor. This brake system locked the blade pitch in place when no current was flowing to the propeller essentially a dead man&rsquos switch. In contrast to the VDM propeller that used creep-resistant worm gears to rotate the base of the propeller blades, Curtiss used spur, planetary, and bevel gear trains in their propellers at the time, thus the need for a propeller brake to keep the blades from migrating back to low pitch by centrifugal twisting moment. Cam-activated low pitch stop and high pitch stop switches were incorporated in the gear train to stop the motor at the opposing ends of the pitch range. (Fig. 6) The pitch change motor used a sequence of spur and planetary gears mounted on the periphery of the hub to generate the torque required to change the pitch of the highly-loaded blades. The considerable torque generated by the relatively large diameter of the electric motor was multiplied further by the 2,298 to 1 gear reduction ratio. The motor had to spin 191 revolutions to achieve the full 30° range of blade pitch change. The entire reduction gear train is mounted in ball bearings, sealed, and immersed in lubricating oil. (Fig. 7)

The actual reduction gear train is illustrated in Figure 8 The motor spur gear in blue meshes with the red-to-green-to-yellow series of spur gears. The gear on the opposite end of the yellow shaft acts as the sun gear that drives blue planet gears that drives the red bell gear. And finally, the spur gear atop the bell gear drives the periphery of the green power ring gear. The beveled gear surface of the power gear drives all three blade segment gears in synchrony. Needless to say, there is a lot of precision machine work in the Curtiss assembly.

Fig. 5. The Curtiss Electric hollow bore electric propeller Model C6315SH showing the constant speed propeller governor and brush block that transfers electrical signals to the propeller via hub-mounted slip rings. Fig. 6. Cutaway of the Curtiss electric C6315SH propeller. This propeller provided the basic design for the inboard component of the Curtiss contra-rotating propeller units. Fig. 7. Exploded photograph of the electric motor and concentric reduction gearing elements for the Curtiss C6315SH hollow bore propeller. Reduction ratio was 2,298 motor revolutions per to 1 revolution of the propeller blade in the hub socket. However, maximum pitch travel is 30°. Fig. 8. Colorized side view of the Curtiss C6315SH propeller gear reduction path. The motor drives three sequential sets of spur gears to a planetary bell gear system that drives the Power gear. The Power gear meshes with segment gears on the three propeller blades to effect pitch change.

Fig. 9. The Robert M. Stanley US patent 1,962,289 granted January 1, 1935, describing a planetary gear system for changing the pitch on a rotating aircraft propeller.
Fig. 10. Stanley/VDM (Vereinigte Deutsche Metallwerke) pitch change operating schematic of the planetary gearing system used in the German hollow bore VDM propeller. Briefly, an electric motor drives pinion C to rotate gear G that re-indexes the planetary gear train. This results in gear N turning gear P that rotates a worm gear at the base of the blade to effect pitch change. A VDM propeller hub is shown in the photograph at the bottom right.

The Curtiss Model C(57)615SP-A contra-rotating propeller utilizes the basic design of the P-39&rsquos C6315SH single rotation propeller for the inboard component of the CRP but with a few modifications. To minimize the distance between the blade discs and improve braking efficiency, the friction surfaces of the pitch brake has been moved from the back of the motor on the P-39 prop to friction faces attached to the three reduction pinions on the CRP power unit. Eighteen springs closed the brake and three solenoids opened it. The pitch of the outboard propeller is mechanically slaved in lock-step to the inboard component via a system of planetary gears patented for single rotation propellers by American Robert M. Stanley in 1935 (Fig. 9). This planetary gear system was used by VDM in their hollow-bore electric propeller that was used on great majority of the German aircraft in WWII, including the Messerschmitt Bf-109, Focke-Wulf Fw-190, Dornier Do-217, and Heinkel He-177.

The operational schematic of the Stanley system is illustrated in Figure 10. Importantly, only gear J is firmly attached to the propeller shaft. Shafts holding gears L and C are stationary, held by the engine housing C is the pitch change input gear and L is free to spin on its own axis, but does not orbit. All the other gears are free to both spin on their own axis as well as orbit on their carriers. The mismatch in gear tooth number between J-H-K is returned back to neutral by the identical gear tooth number mismatch between K-L-M, thus the gears can be thought to &ldquorun in place&rdquo with no indexing change, or load, occurring until a pitch change is commanded. The movement of G &ldquore-indexes&rdquo the downstream gears in the train, ultimately causing N to rotate P, which drives the blade pitch worm gear.

As already described, the gear reduction train to change the pitch of inboard propeller blades of the C(57)615SP-A CRP is essentially identical to the open-bore Curtiss C6315SH used on the P-39 and shown schematic form in Figure 11.

Now considering the outboard component of the Curtiss CRP, the mechanical power for changing the pitch on the outboard propeller is taken off a spur gear connected directly to the electric motor of the inboard component. Three torsion shafts that transmit the pitch change from the inboard to the outboard component. This means the outboard component must deliver the same 2,298 to 1 reduction ratio as the inboard prop for the blade discs to remain in lock step. This reduction is achieved by the Stanley gears and the speed reducer attached to the center of the outboard prop hub. The two components of the C(57)615SP-A CRP are delineated in Figure 12, and the complete propeller shown on the electric whirl test stand in Figure 13.

Fig. 11. Curtiss C(57)615SP-A Inboard Pitch Change Gear Train. A donut shaped electric motor drives reduction gear trains that rotate the Power ring gear, thereby changing the pitch on all three propeller blades via segment gears on the blade bases. Fig. 12. A Curtiss contra-rotating propeller assembly mounted on an aircraft. As demarcated by the red line, the inboard component containing the electric motor rotates clockwise while the outboard component that contains the Stanley gears rotates counter clockwise as viewed from the rear. Fig. 13. Curtiss C(57)615SP-A contra-rotating propeller is shown on the electric whirl test stand. What looks to be a radial engine is the special CRP gearbox. This testing provides data for thrust and blade deflections at various settings of pitch, horsepower, and rpm. Endurance testing and overspeed to 130% and horsepower levels exceeding 160% of rated power were performed. A maximum static thrust of 6,760 lb was achieved at 1,386 rpm on 2,832 horsepower, or 2.4 pounds of thrust per horsepower.

Shown schematically in Figure 14, the sun gear of the Stanley gear train is driven via spur gear and torsion shaft off the motor of the inboard component, fulfilling the function of the Gear J in the Stanley/VDM schematic in Figure 8. This sun gear drives the rest of the Stanley gear train that is housed entirely in the outboard component. There are three flexible drive shafts (L) to share the loads coming from the Stanley gear train up to the speed reducer assembly mounted on the center of the outboard hub. These three flexible transfer shafts, as well as the three torsion shafts bridging the inboard and outboard components, are flexible to compensate for induced misalignments and inertia of the numerous precision gear train components whirling on overhung propeller shafts in opposite directions. The pinions of the flexible shafts engage the perimeter of a central spur gear in the speed reducer. This spur gear in turn drives a single stage planetary gear, and the planet gear carrier is splined to a spiral bevel gear that meshes with the segment gears on the base of the blades. (Fig. 15) The presence of Zerk fittings indicates the outboard speed reducer runs in grease.

Fig.14. Curtiss Outboard Pitch Change Gear Train. Gears are represented by the shaded rectangular boxes and the letter designations refer to the functionally equivalent gears in Figure 8. Drawing is not to scale. Fig. 15. Speed reducer assembly for the outboard propeller of the Curtiss C(57)615SP-A CRP. The three shafts run from the Stanley gears up to the spur and planetary reduction gear sets in the speed reducer. The central spiral bevel gear engages the segment gears on the base of the propeller blades.

The inboard and outboard reduction gear trains of the C(57)615SP-A CRP are shown schematically in Figure 16. The actual Stanley gear train components are shown in Figures 16a, 16b, 16c, and 16d. The unit ran immersed in oil.

Fig. 16. Curtiss C(57)615SP-A Contra-Rotating Propeller Pitch Change Gear Train. Motive power supplied by an electric motor on the inboard component. Reduction gearing contained in both the inboard and outboard components provides the torque to change the pitch of the six total blades in synchrony. Gears are represented by the shaded rectangular boxes and the letter designations refer to the functionally equivalent gears in Figure 8. Drawing is not to scale. Fig 16a. Components of the Stanley gear train in assembly sequence, left to right, inboard to outboard. Fig 16b. Inboard face of the Stanley gear set. Coupler from the electric motor acts as the sun gear for this assembly. Fig 16c. Outboard face of the Stanley gear set. These gears ultimately drive the three pinions of the flexible shafts that run to the speed reducer. Fig 16d. Underside of the Flexible Shaft Assembly. The pinions are driven by the Stanley gear set and rotate the flexible shafts.

Fig. 17. Intershaft bearing #49 is shown in orange. The inner race seats on the outboard propeller shaft (green) while the outer race is located on the inboard propeller hub (blue). The inboard propeller shaft is shown in dark red and the outboard propeller hub to the left in brown.

Common to all dual rotation propeller systems, whether coaxial or contra-rotating, an intershaft bearing was used take up the radial loads placed on the overhung coaxial shafts by the propellers during operation. The inner race of bearing sat on the outboard propeller shaft while the outer race engaged a relief on inboard hub. (Fig. 17) The contra-rotating C(57)615SP-A propeller unit weighs 739 pounds.

There is a complicated art and science to selecting blade diameters, blade area, blade pitch distributions, and relative blade pitch to best match the leading and trailing propeller discs to reduce vibration and noise, maximize efficiency, and equitably distribute blade loadings. Because of the swirl coming off the leading propeller disc, the trailing propeller disc sees an accelerated airflow as well as a modified angle of attack of the incoming airstream. Because of this, it is most common to have the blades of the trailing propeller indexed 0.5 to 2 degrees finer (lower pitch) than the blades of the leading propeller disc. It seems counterintuitive, but CRP manuals from Rotol, Aeroproducts, and Curtiss, as well as USAAF whirl testing reports, confirm this pitch differential. Indexing Curtiss propeller blades in 0.3° increments was made possible by a fine-tooth spline coupling between the final reduction gear and the power gear. Indexing of individual blades in the hub was not possible in this design, rather blades were carefully indexed, component-matched, and pinned to their segment gears at the factory.

Prop shaft spline sizes are indicated by the numbers in the parentheses of the Curtiss model number. The inboard prop hub for Curtiss C(57)615SP-A contra-rotating propeller used on the R-3350 powered Curtiss XP-62, and the R-4360-14 powered Curtiss XBTC-1, was a 70 spline the outboard hub was a 50 spline. The Curtiss C(46)615SP-C1 propeller used in the pusher configuration for the R-2800-29 powered XP-56 had a 60 spline hub inboard and a 40 spline hub outboard. American turboshaft CRP&rsquos typically used 80 spline shafts inboard and 60 spline shafts outboard.

The Curtiss CRP units for piston-powered aircraft were used on the XP-56, XP-60C, XP-62, XF14C-2, and XBTC-1. (Figs 18, 19, 20, 21, 22) Notably, all but the XP-56 were Curtiss-Wright designs.

The pusher Curtiss CRP in the Northrop XP-56 flying wing suffered from vibration issues and repeated breakage of the torsion shafts that transmitted pitch change to the outboard component, but this was perhaps due to the unique propulsion system (R-2800 + cooling fan + long drive shaft + remote contra-rotating reduction gearbox + contra-rotating propellers) and not necessarily the CRP design. The Curtiss CRP flown in the R-4360-powered XBTC-1 proved harmonically incompatible with the engine and airframe, necessitating a change to an Aeroproducts AD7562 CRP. In fairness, the Curtiss XP-60C was an aircraft of many compromises, delays, and design changes, but flew and performed quite well with the Curtiss CRP. Alas, by 1943 the modest improvement in performance with the CRP didn&rsquot justify a war time investment in the P-60 design.

In stark contrast to the Rotol and Aeroproducts CRP systems, all Curtiss CRP systems remained experimental and never entered production or military service, before, during, or after WWII.

Fig. 18. Northrop XP-56 propelled by the Pratt & Whitney R-2800-29 radial engine and Curtiss Model C(46)615SP-C1 contra-rotating propellers. Inboard propeller is 9 ft 7 5/8 in diameter outboard propeller is 9 ft 6 in diameter. Aircraft was constructed of welded magnesium and propellers were jettisonable for emergency egress in flight. Fig. 19. Curtiss-Wright XP-60C propelled by the Pratt & Whitney R-2800-53 radial engine and Curtiss Model C(46)615S-C contra-rotating propeller of 12 ft 2 in diameter. Fig. 20. Curtiss-Wright XP-62 propelled by the Wright R-3350-17 turbocharged radial engine and Curtiss Model C(57)615S-B contra-rotating propeller of either 13 ft 11/16 in diameter or 13 ft 2 1/2 inch diameter. The cockpit was pressurized. Fig. 21. Curtiss-Wright XF14C-2 for the US Navy, propelled by the Wright XR-3350-16 turbocharged radial engine and Curtiss Model C(57)615S series contra-rotating propeller approximately 12 ft 10 in diameter. Fig. 22. Curtiss-Wright XBTC-1 for the US Navy, propelled by the Pratt & Whitney R-4360-8a radial engine and initially used Curtiss Model C(57)615S series contra-rotating propeller of 14 ft 2 in diameter. Subsequent test flying was done with an Aeroproducts AD7562-X14 CRP 13.5 ft in diameter. Two protypes were built.

As the jet age emerged towards the end of WWII, aviation nations began to investigate turbine-driven propellers as a more efficient technology compared to the fuel guzzling, range limited, and long take off characteristics of the early turbojets. Rapid progress in the turbine field had soon production turboshaft engines generating 5,000 horsepower by 1949, and 14,000 horsepower by 1952. Harnessing this immense power, plus the unique characteristics of the turboshaft engine to both prefer constant engine speed and detest being driven by the propeller, was an incredible challenge for the propeller technology of the time. Curtiss Electric Propeller Division was a firm believer that contra-props were the future and invested heavily in designing building six and eight bladed contra-rotating turboelectric propellers of up to 19 ft in diameter. (Fig. 23).

Remarkably, the operating scheme of the Curtiss Turboelectric CRP is identical to the mechanism used for the piston-powered CRP described above except for the source of motive power and the complexity of the propeller governor. Because of the gargantuan centrifugal twisting moments of large and heavy blades compelling the blades towards low pitch, electric motors were nearing the practical limits of their ability to drive the pitch change mechanism. And more importantly, the large reduction ratios required to produce the necessary torque via electric motors, as well as the inertia in the system, meant that these propellers were rather slow acting, which was a huge disadvantage when trying to control the rpm of a screaming turbine to within a few percentage units using primarily changes in propeller pitch.

The Curtiss solution was to use the vast power of the propeller drive shaft itself as the power source for pitch change. (Fig. 24) This was accomplished by having a spur gear sleeved to the prop shaft that would act through a gear machined in the body of an electrically-operated clutch pack. The central shaft exiting the clutch pack would act through a pinion to operate the planetary gears of the Stanley pitch-change mechanism. (Fig. 25) There were separate clutch assemblies for increase pitch, decrease pitch, propeller brake, and feathering motor. Like a master pianist, the propeller governor would activate and deactivate the various clutches at the appropriate times to maintain the proper engine/propeller speeds via pitch change. It was an extremely demanding service for the clutches, but they provided the rapid pitch change rates required by the application. It took some time to design and schedule the propeller governor to minimize actuation delays, manage the inertia/momentum in the system, and hunting due to switching hyperactivity.

Fig. 23. Curtiss-Wright Propeller Division brochure from 1950 showing an 8 blade, 19 ft diameter Turboelectric CRP as well as descriptive information for six and eight blade CRP units capable of handling up to 20,000 horsepower. Fig. 24. Schematic diagram showing the pitch change system for the contra-rotating Curtiss Turboelectric propeller. Motive power was extracted from the propeller shaft via electronically activated clutches. In contrast to the Curtiss CRP&rsquos used in piston-powered applications, the Turboelectric propellers used on turboshaft engines utilized worm gears at the base of the blade to change pitch. Fig. 25. Exploded parts diagram of a Curtiss pitch change clutch unit used on the single rotation CT35S Turboelectric propeller on the Douglas C-133. When energized, the coil (15) retarded a rotating armature (20) that, through a spur-type planetary gear system (17.18.19), turned a ball ramp force multiplier (13,25) to compress the clutch plates (5,6) axially together and engage the clutch to drive the output pinion gear (4). The pitch change clutches ran in oil the brake clutch ran dry. Fig. 26. Drawing of the eight blade Curtiss Turboelectric contra-rotating propeller.

Perhaps the crowning achievement of precision propeller control was the contra-rotating Curtiss Electric C(6L8)64S-A propeller used in the Convair XFY-1 and Lockheed XFV-1 &ldquoPogo&rdquo aircraft during the early 1950&rsquos. (Fig. 26, 27, 28) These aircraft were designed as vertical takeoff and landing point defense fighters and were powered by the Allison T40-A14 turboprop engine of 5,830 equivalent shaft horsepower. (Fig. 29). To accommodate the horsepower, an 80 spline hub was used on the inboard component and a 60 spline hub on the outboard propeller. The propulsion system generated in excess of 17,000 pounds of static thrust. (Fig. 30) The XFY-1 demonstrated hovering capability with full transition flight occurring on November 4, 1954. This could only be achieved by CRP&rsquos as torque from a single rotation propeller could not otherwise be managed.

The ability to modulate engine power while at a constant engine speed via propeller pitch and fuel control with a finesse that allowed not only hovering flight, but fine and yet rapid control of descent rate was an astonishing accomplishment in the very demanding, zero airspeed environment. This flight regime required a highly skilled pilot, and only one pilot, aeronautical engineer, Marine reservist, and Convair test pilot James &ldquoSkeets&rdquo Coleman, achieved transitional flight. While the Allison T40 with Aeroproducts CRP units had terminal problems in typical aircraft applications (Douglas A2D Skyshark Convair R3Y Tradewind North American XA2J-1 Super Savage), it should be noted that the T40 with the Curtiss CRP performed without accident or loss of life during the XFY-1, XFV-1, and Hiller X-18 programs.

As turbojets evolved to more efficient turbofans, the need for very large propeller driven aircraft waned, sounding the death knell for American contra-rotating propeller systems. Curtiss Electric&rsquos last CRP effort was an eight bladed behemoth 18 ft 3 inches diameter for potential use in the unbuilt, four engine Douglas XC-132 tanker/transport powered by the Pratt & Whitney T57 turboshaft engine of 15,000 horsepower. (Fig. 31) The T57 was flown in a test bed but used a single rotation propeller.

Fig. 27. Drawing of the XFY-1 in hovering flight by Dan Witkoff, signed by pilot Skeets Coleman. Artwork is in the collection of the Rolls-Royce Heritage Trust Allison Branch, Indianapolis, Indiana, USA. Fig. 28. Lockheed XFV-1 located at the Florida Air Museum, Lakeland, Florida, USA. Flight testing of the XFV-1 utilized a jury-rigged landing gear for standard horizontal takeoff and landing. While near-hovering flight of 80° was achieved during flight test, the XFV-1 never took off or landed vertically. Fig. 29. Allison T40-A10 turboshaft engine in the collection of the Rolls-Royce Heritage Trust Allison Branch, Indianapolis, Indiana, USA. This particular version has the accessories on the top of the engine while the T40A-14 used in the XFY-1/XFV-2 had the accessories on the bottom for serviceability.
Fig. 30. The Curtiss Turboelectric C(6L8)64S-A propeller used on the Convair XFY-1 and Lockheed XFV-1 was 16 ft in diameter. Fig. 31. The proposed Douglas XC-132 heavy transport was to be powered by the Pratt & Whitney T57 turboshaft engine and either Hamilton Standard Model B48P6A single rotation propellers 20 ft in diameter or eight bladed Curtiss Turboelectric contra-rotating propellers 18 ft 3 inches in diameter. The aircraft was never built.

Curtiss lost out to Aeroproducts and Hamilton Standard on supplying propellers for the Lockheed C-130 and the Lockheed L-188 Electra. Curtiss Electric&rsquos final single rotation Turboelectric propeller was used on the fifty, four engine Douglas C-133 Cargomaster heavy transport aircraft that flew from 1956 to 1971. Curtiss soon faded away as a propeller company.

The Russians have persisted to the present time with their remarkable Tu-95 and An-22 aircraft using CRP units. And in the 1980&rsquos, as well as the 2017 first run of the SAFRAN Open Rotor, there has been intermittent revival of dual rotation propeller sets, albeit they are technically and more rightly designated Propfans, Ultra High Bypass (UHB), Unducted Fans (UDF), or presently, Open Rotors. And that is topic for another time.

Tail end of Northrop XP-56 showing the contra-rotating propeller shafts. Inboard shaft is 60 spline, which has 32 spline teeth. Outboard shaft is 40 spline with 16 teeth. Encircling the inboard prop shaft is the brush block retainer with the rectangular opening for the brush block at 8 o&rsquoclock. Cooling flaps and linkages with master actuator at 12 o&rsquoclock. NASM Garber Facility, May 2010. Inboard (left) and outboard (right) prop hubs with spinner backplates for Curtiss Electric C(46)615SP-C1 from the XP-56. Note the holes in the backplate between the blade sockets in the outboard hub through which the flexible shafts run to the speed reducer. NASM Garber Facility, May 2016. Rear view of the inboard component of the Curtiss Electric coaxial propeller on the Douglas XB-42A. The outboard propeller and components have been removed. Note the electrical posts in the bore of the outboard propeller shaft that controlled the electric pitch change mechanism in the outboard propeller. NASM Garber Facility, May 2010. Partially disassembled outboard propeller on the Convair XFY-1. Aircraft is sitting horizontal on its dedicated tilting transporter. The 6 o&rsquoclock blade has been removed to remedy corrosion in the extruded hollow steel blade. NASM Garber Facility, May 2016. The Hiller X-18 was an experimental vertical lift aircraft that utilized the Allison T40/Curtiss C(6L8)64S-A CRP propulsion systems from the cancelled XFY-1 and XFV-1 programs with a jet engine in the aft fuselage for maneuvering thrust. It never achieved vertical takeoff or hovering flight.

Handbook of Operating and Maintenance Instructions Curtiss Hollow Shaft Electric Propeller, Technical Order Number T.O. 03-20BG-4, April 15, 1943.
Handbook of Instructions and Parts Catalog Hollow Shaft (Three Blade) Propeller Model C6315SH, AN 03-20BG-1, A.P. 2110A, 20 January 1944.
Type Test of Curtiss Dual Rotation Propeller Model C(57)615SP-A with Blades of Design Nos. 614-1C1.5-6 and 615-1C1.5-6, Army Air Forces Technical Report 5212, Whirl Test No. 1677, 26 March 1945.
Type Test of a Curtiss Dual Rotation Propeller Model Number C(57)615S-B with Curtiss Design Number 726-1C1.5-0 and 727-1C1.5-0 Blades for Use on an XP-62 Airplane Powered with an R-3350-17 Engine, Army Air Forces Technical Report 5377, Whirl Test No. 1689, 28 November 1945.
Type Test of a Curtiss Dual Rotation Propeller 9 Ft. 6 In. Diameter Model Number C(46)615SP-C1 with Blades of Design Nos. 512-4C1.5-18 and an Aircraftsman AC-104 Spinner, Army Air Forces Technical Report 5247, Whirl Test No. 1697, 26 July 1945.
Final Report on Inspection, Performance, and Acceptance of Curtiss-Wright XP-60A, C, and E Airplanes, Air Corps Technical Report 5286, 1945.
Final Report on Development, Procurement, and Acceptance of the XP-56 Airplane, Air Corps Technical Report 5714, 1948.
Curtiss Turboelectric and Turbo-Prop Engines Brochure, Copyright 1950, Curtiss-Wright Corporation Propeller Division.
Bladesman, publication of the Curtiss-Wright Corporation Propeller Division, November 1942.
The Design and Operation of Hollow-Shafted Constant Speed Propellers Part 2: The Curtiss Electric Propeller by Tom Fey. Torque Meter, Vol, 2, Number 2, Spring 2003.
US Patent 1,986,229 for a Controllable Pitch Propeller granted to Robert M. Stanley, 1 January 1935.
US Patent 2,533,346 for a Dual Rotation Propeller granted to George W. Bray and Charles W. Chillson, 12 January 1950.
XP-56 flight video:
XFY-1 Flight video with Skeets Coleman interview:

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Battle With the Air

Thousands of Clevelanders watched as Glenn Hammond Curtiss paced the Euclid Beach Park pier on the morning of August 31, 1910. Many had skipped work that day in hopes of watching him set out on his planned 65-mile overwater flight to Cedar Point, near Sandusky. Some grew restless as time wore on, recalling that the airman had recently canceled trial flights due to high winds.

Curtiss’ fragile flying machine, dubbed the Hudson Flyer, was powered by a 60-hp engine. It had been shipped around the country to fulfill invitations that poured in after his record-breaking flight down New York State’s Hudson River four months earlier. Shortly after the 32-year-old aviator arrived in Cleve – land, he had announced that his biplane was not ready for a test flight. A second scheduled trial had also been postponed.

Aside from sending a few colorful balloons into the leaden sky, Curtiss evaluated conditions simply by walking the pier and observing his shadow. “My coat is my wind gauge,” he explained to reporters. “When it flaps evenly, I know the wind is steady.” On the morning of August 31, his coat was flapping wildly in the breeze. Knowing a forced landing could turn his wood, fabric and wire aircraft into kindling, he reluctantly postponed his record attempt. “The hardest thing in flying,” he told reporters, “is to correctly assess when it is wise to remain on the ground.”

What Curtiss didn’t say was that it would be especially wise not to jeopardize the lucrative flight to Cedar Point, which he had contracted with the Cleveland Aero Club and Cleveland Press to attempt. He stood to earn as much as $15,000 in prize money by surpassing the 50-mile mark he had set in Atlantic City just two months earlier.

When Curtiss returned to the beach that afternoon for another trial, he was dressed to fly—girdled with inflated inner tubes to keep him afloat if the airplane plunged into the lake. His wife, Lena Pearl, fingered her beaded purse nervously as the Hudson Flyer was rolled out onto the 300-foot plank runway and her husband climbed into his seat.

The engine coughed to life, belching a cloud of dark smoke. Hundreds of boats sounded bells and whistles as Curtiss powered down the plank runway. The crowd held its collective breath as the plane wallowed dangerously, then burst into applause as it began the climb out over the lake for a brief trial flight. Minutes later they greeted his return with cheers.

Curtiss had accepted the invitation to Cleveland following 12 months of exploits that pushed the envelope of aviation and burnished his reputation as one of America’s leading airmen. Just a year earlier, on August 29, 1909, he had been acclaimed the world airspeed king after edging out France’s Louis Blériot to win the first international air race at Reims. He started 1910 with another triumph at America’s first large-scale airshow, held in Los Angeles on January 20, averaging 54.7 mph in another of his own biplanes. Then, on June 30, he offered U.S. Navy officers an early demonstration of the airplane’s military potential, dropping lead pipes on a target configured like a warship. Eighteen of his 20 “bombs” struck the target.

Those achievements built on the celebrity Curtiss had gained in 1908 with the Aerial Experiment Association, organized by Alexander Graham Bell to advance the science of flight. Curtiss was at the controls of the AEA’s June Bug when it flew just under a mile on July 4, 1908, the first official airplane flight of more than a kilometer (see “Into the Air” in the July 2009 Aviation History).

From the public’s standpoint, Curtiss’ star status was clinched by his 150-mile flight down the Hudson from Albany to New York City on May 29, 1910. The man who had first demonstrated his courage as a daredevil motorcycle racer was never one to dodge a challenge. Nor was he inclined to overlook the $10,000 prize that publisher Joseph Pulitzer promised the first “aeronaut” to make the flight. Defying turbulent winds, Curtiss completed the trip in just two hours and 51 minutes, with a single refueling stop.

Within a week, promoters across the country had posted an estimated $200,000 in prize money, hoping to attract Curtiss or other famed aviators. Atlantic City offered $5,000 for a flight over a stretch of ocean, a prize Curtiss claimed after flying laps off the city boardwalk on July 4. The city boasted that the 50-mile flight established an over-water record—one that Cleveland boosters immediately invited Curtiss to break.

August 31 had dawned clear, and when the airman came out early to check the weather he was wearing what might have passed for business casual in those days. Still, he donned a flier’s cap and goggles, since the test flight showed him that he needed to protect his eyes from sand whipped up by the prop.

Curtiss rattled down the plank runway at 1:06 that afternoon. With the wind at his back, he lifted off just moments before he would have crashed into the surf and a concrete piling. As one reporter described it, “Curtiss missed disaster and probable death by a hair’s breadth.” The airman coaxed his plane out over the lake before banking westward and easing up to 300 feet. His foot on the gas feed, he bent over the steering wheel and tracked elapsed time with a watch clamped to the control column.

Seven minutes after takeoff, the flier passed within view of Cleveland Harbor, where an estimated crowd of 100,000 waved him on. Soon a flock of curious seagulls was cruising alongside him. Minutes later he could make out the slender peninsula that was Cedar Point.

Out on the point, thousands followed re – ports of his progress, relayed via telephone and telegraph. A man with a megaphone announced his approach, and soon someone pointed and shouted, “It’s Curtiss!” As he got closer, “men and women seemed to lose their senses,” according to the Sandusky Daily Register. “For a moment they stood and gazed in open-eyed wonderment,” then rushed forward. “Moans, shrieks and sobs all added to the confusion prevailing.” Police – men held back the crowd as the Hudson Flyer bounced along the beach for about 100 feet before coming to a stop. Now the crowd rushed toward Curtiss, some trying to hoist him up onto their shoulders. But Curtiss wasn’t having it. “I must telephone my wife,” he protested.

The airman frustrated reporters by insisting there had been nothing particularly remarkable about the record-breaking flight. From his perspective, he was simply a businessman doing his job. He had covered the 60½ miles to Cedar Point in one hour and 18 minutes, an average of 46.1 mph—“the speed of a rocket,” according to one breathless report. Curtiss, who had sped to a world record 136 mph on a motorcycle three years before, must have rolled his eyes at such hyperbole. But he would gladly pocket his prize money for completing the first half of the round trip.

A downpour changed his plans of flying back to Cleveland right after his aircraft was serviced. Instead he accepted the offer of Cedar Point proprietor George Boeckling to stay overnight and attend a banquet in his honor. Although he despised such affairs, Curtiss recognized the need to cooperate with his sponsors. Before his return trip, he told Boeckling (and eavesdropping reporters), “This will be the most remarkable flight ever made, and this is the most ideal and most beautiful place for such events.”

The following morning brought more wind, and another delay. When the winds subsided, he made a demonstration flight, then took off at 2:47 p.m. for Cleveland. Lifting off into a clear sky, he had no reason to suspect that he would soon be fighting for his life. He quickly encountered what he de – scribed as “a veritable whirlpool of air” that kept him struggling to stay aloft. “Even a small puff of wind striking the machine hit with terrible force,” he recalled. “The ma – chine quivered and shook.”

Flying at 500 feet into what he described as “the teeth of a 20-mile gale,” Curtiss plummeted 100 feet after hitting a downdraft. Throttling back, he regained control, but his hands grew numb from the cold, and his back ached from rocking back and forth to help maintain level flight. He hastily pulled down his goggles when rain began pelting his face.

By the time he touched down, he was too exhausted to acknowledge the welcoming throng. “It was a battle with the air every mile of the way from Cedar Point,” the weary flier told reporters. “Several times I feared I would be dashed into the lake.”

Local newspapers blitzed readers with the story of the first flight over the Great Lakes. But Curtiss’ accomplishment drew only brief national attention. The over-water record itself would stand for just five months before another pilot, John McCurdy, broke it with a 90-mile flight from Key West to Havana. McCurdy was a member of a new exhibition team that Curtiss incorporated one day after his Cedar Point flight, a move that signaled the New York aviator’s intention to concentrate on aircraft development and manufacturing.

After Glenn Curtiss’ death in 1930, Cleveland newspapers recalled his Lake Erie flight, eulogizing the former motorcycle racer as a man whose contributions to flying matched those of the Wright brothers. “In skill, courage, resourcefulness and enthusiasm, he was surpassed by few in the history of aviation,” the Cleveland Press editorialized. “He was one of the great.”

Originally published in the July 2010 issue of Aviation History. To subscribe, click here.

Collection of aviation-related photographs (original & prints), press photos, US army intelligence, postcards, magazine clippings, worksheets, some patches, and booklets. Comprised of 19 albums housed in 3-ring binders, mostly 3-inch binders. Subject matter includes helicopters, fighter Jets, and albums covering almost every type of plane in between. Contains 500+ items, including approx. 375 photographs. The list below outlines highlighted photographs included in the collection (organized according to contents of each binder):

HB - B24 [Leustpme B-7 XB-1B LB-10A XB-7 B-9 B-10 (B) B-12 UB-17 XB-17 B-17 (E, G) B-18 XB-19A B-23 B-24 (J, M, D) LB-30A]: 24 photos.

F-81 thru F-84 [F-82B "Twin Mustang" F82C F84F F-84G]: 13 photos and 2 color realphoto postcards.

H-1 thru H54 (helicopters): [R-985-AN-5 R-6 H13-B R-13 YH-18A YH-21 CH-21B H-25A HH-43B CH-47 HH-60D UH-1N/HH-1H Ch-3/HH-3]: 16 photos plus one realphoto postcard.

UC-75 YC-97 XC-99 C-119J: 19 photos.

Curtiss O-1 Falcon Douglas O-2 O-38 N: 6 photos.

: V VTOL ISTOL Grumman HU-16A "Albatross" X-3: 12 photos.

P-39 thru XP-57: YP-39 P-39F, D, Q P-40, E P-51B, C "Mustang" 19 photos, 6 Realphoto postcards, plus 1 patch with sun and star on a shield.

F-85 thru F-89: F-85 "Goblin" F-86A, C, D F-86L Flight handbook XF-88 F-89 "Scorpion" F-89-D: 15 photo, 2 realphoto postcards.

F-104 thru F-117: F-104, C "Starfighter" F-105, B, D, F "Thunderchief" F106, A "Delta Dart" F-107 F-108A "Rapier" F110 F111 F117 "Nighthawk": 19 photos, 5 realphoto postcards.

C-120 thru C-132: -120 -121A VC-121B C-121C EC-121D YC- 122 B &C XC-23A C-123B 1C-124A-2 C124A-C YC-15 "Raider" LC 126AC-130 A, E "Hercules" C-131B XC-132: 17 photos, 7 RPPCs.

B-47 thru FB-111: B-47, B, E "Stratojet" B-50D B-52, A G "Stratofortress" B-57 A, B, C, D, E, F B-58A Flight Manual (photocopy?) "Hustler" Rb-66, A B-70 "Valkyrie" FB-111, A: 30 photos, 9 RPPCs.

FM, PB, PW, TO / P-1 thru P-38: PW-9C "Hawk" FM, YFM-1 P-1, B, D XP-6, A P-6El P-11 P-12, E, F XP-15 Y1P-16 XP-17YP-20 XP-21 XP-22 Y1P-25 P-26, A P-29A P-30A XP-31 P-35 P-36, A, C "Mohawk" P-40 "Tomahawk" XP-37 YP-38 P-38, E, L "Lightning": 28 photos, 12 RPPCs.

B-25 thru B-46: B-24 "Liberator"B-25, B, C, D, J ("Panchito"), N plus "Panchito" patch B-26, B, C "Maurader" B-29 "Superfortress" XB-35 B-36A RB36, D, F-H "Peacemaker" XB-43 "Tornado" B-45 A, L XB-46: 17 photos, 17 RPPCs.

New Series / F-1 thru : 2 patches - 27th Fighter wing and 37th Tactical Fighter wing F-4, cc, D, E, H "Phantom" F-5, E "Tiger" YF-1A "Interceptor" F-14A "Tomcat" F-15 "Eagle" F-16, C "Fighting Falcon" F-20 "Tigershark" YF-23: 18 photos, 7 RPPCs.

F-90 thru XF-103: F-90 XF-91 F-91 "Thundercepter" F-92, A F-93 F-94, A, C plus Handbook for F-94 F-95 YF96 YF-97 F-100, C, D "Super Sabre" F-101, A, B, C "Voodoo" F-102, A, B "Deltadagger" F-103: 19 photos, 6 RPPCs.

1908-1924: Early military planes from all over the world, including Britain and Germany. Zepplins/dirigibles and balloons Curtiss W4s (WWI biplane) JN-4D "Jenny" SE-5, a (Britain) MB-2 MB-3A MB-4 DeHavilland 4-B Martin NBS-1 Curtiss PWS "Hawk" XNBS-4 Witteman XNBL-1 Thomas-Morse R-5, and more: 60 photos plus 14 RPPCs.

Amphibian thru Attack: Sheet of 37 cent stamps with 20 different planes Grumman OA-9 OA-10 OA-12 two patches - winged star and 3-arm swirl, blue on gold A-3 "Falcon" A-8 "Shrike" YA-9 YA-11 YB-10 XA-16 XA-19 A, B, C Douglas A-20B, G A-24 A-26 "Invader" A-27 A-28 A-31 "Vengeance" A-36 "Invader" A-7D A-10 A A-11 A-37B: 28 photos and 9 RPPCs.

C-1 thru C-69: 2 patches - Air Transport Command and Military Airlift Command C-1, Fokker C-2 C-8 Y1C-12 Y1C-15Y1C-17 Y1C-19 Y1C-21 Y1C-23 Y1C-25 Y1C-27 C-27, A, C C-29 XC-32 C-32A C-33 C-34 XC-35 C-38 C-39 C-40, A C-41 C-42 D-17 XC-44 C-45 C-46E C-47, B, D C-48, A, B, C C-49, A, B, C, D, E, F, G, H J, K C-50, A, B, C, D C-51 C-52 C-53 C-54 C-56, A, B, C, D, E C-57, A, B C-59 C-60 C-61- C-633 C-65 C-66 C-67: 11 photos, 7 RPPCs.

Curtiss XP-17 - History

On December 7, 1941, seventy-five years ago tomorrow, P-40 fighter planes built in Buffalo defended Pearl Harbor during the Japanese attacks. This picture shows Curtiss-Wright Corporation’s Plant #2, a 1.5 million ft2 factory built in 1940-1941 on the site of the present Buffalo-Niagara International Airport to manufacture Curtiss-Wright’s P-40, known variously as the Warhawk, Kittyhawk and Tomahawk. Later in December 1941, P-40s carried the Flying Tigers into their first dogfights in the Far East and flew with the British in North Africa against the Luftwaffe.

The P-40 in the foreground has a woman worker standing on its wing who may have just filled the oil tank located in front of the cockpit (see the hose and nozzle laying on the wing). Women played a critical role in manufacturing during WWII, while most men were in the service. These “Rosie the Riveters” helped pave the way for women in the workforce today. This picture reportedly dates from 1943 but shows no sign of a September 11, 1942 accident when a P-40 on a test flight crashed through the roof of Plant #2 killing 14 workers and injuring many others. By 1943 the P-40 was outclassed by newer aircraft. If you look to the left in the picture, you can see a second assembly line with a radial-engined fighter. These are P-47 Thunderbolts, a Republic Aviation Corporation design, that were made under license by Curtiss-Wright. After P-40 production stopped in 1944, Plant #2 built 2,674 Curtiss-Wright C-46 Commando cargo planes which were best known for flying supplies into China from India over the “Hump” or the Himalya Mountains during WWII.

Following the war, aircraft demand plummeted, Curtiss-Wright moved to Columbus, Ohio and Plant #2 was sold to Westinghouse Electric. For almost 40 years the factory made electronic parts and motors for Westinghouse’s Motor and Industrial Controls Division until it was shut down in 1985. After several failed attempts at reuse, Plant #2 was sold to the Niagara Frontier Transportation Authority and demolished in 1999 to make way for expanding the current airport terminal, tarmac and second runway. Today, the only remnant of Plant #2 is a plaque dedicated to the workers lost in that P-40 crash on September 11, 1942.


[edit] Attack, 1924-1948

  • A-1 - skipped to prevent confusion with Cox-Klemin XA-1 - Douglas - Curtiss - Curtiss - Curtiss - Curtiss - Fokker - Curtiss - Lockheed - Curtiss - Consolidated - Curtiss - Northrop - Curtiss - Martin - Northrop - Northrop - Curtiss - Vultee
  • A-20 Havoc #67 - Douglas (redesignated B-20 in 1948) - Stearman - Martin - Martin - Douglas (redesignated F-24 in 1948) - Curtiss
  • A-26 Invader #8 - Douglas (redesignated B-26 in 1948, then A-26 in 1966) - North American - Lockheed - Lockheed - Martin - Vultee - Brewster - Northrop - Brewster - Vultee - North American - Hughes - Beechcraft - Kaiser-Fleetwings - Curtiss - Vultee - Douglas - Curtiss-Wright - Consolidated - Martin

[edit] Bomber

Until 1926, the Army Air Service had three sequences for bombers. Light bombers were indicated by the LB- prefix, medium bombers by the B- prefix, and heavy bombers by the HB- prefix. In 1926, the three-category system was scrapped and all bombers subsequently built were placed in the B- sequence.

[edit] Unified bomber sequence, 1926-1962

[edit] Cargo, 1924-1962

    - Douglas - Fokker - Ford - Ford - Fokker - Sikorsky - Fokker - Fairchild - Ford - Curtiss-Wright - Consolidated - Lockheed
    • C-13 - skipped
    • C-138 - reserved for Fokker F27, but never assigned
    • C-143 - reserved for what would become the X-19, but never officially assigned

    After 2005, several planes were added to this sequence.

    [edit] Gyroplane, 1935-1939

    [edit] Pursuit, 1924-1948/Fighter, 1948-1962

    Designated P- for "pursuit" until 1948, when the United States Air Force was founded. After this, all P- designations were changed to F- ("fighter"), but the original numbers were retained.

      - Curtiss - Curtiss - Curtiss - Boeing - Curtiss - Curtiss - Boeing - Boeing - Boeing - Curtiss - Curtiss - Boeing - Thomas-Morse - Curtiss - Boeing - Berliner-Joyce - Curtiss
    • Curtiss XP-18 (paper project only)
    • Curtiss XP-19 (paper project only) - Curtiss - Curtiss - Curtiss - Curtiss - Lockheed - Consolidated - Boeing - Consolidated - Consolidated - Boeing - Consolidated - Curtiss - Boeing - Consolidated - Wedell-Williams - Seversky - Curtiss - Curtiss - Lockheed - Bell - Curtiss - Seversky - Curtiss - Republic - Republic - Bell - Curtiss - Republic - Douglas - Lockheed - Grumman - North American - Bell - Curtiss - Vultee - Curtiss - Northrop - Tucker - Lockheed - Bell - Curtiss - Northrop - Curtiss - Bell - North American - Grumman - Vultee - McDonnell - Vultee - Republic - Douglas - Curtiss - Republic - Hughes (officially never assigned)
      • P-74 - skipped
      • F-109 - temporarily reserved for what would become the F-101B, but never officially assigned[3]
      • YF-109 - designation requested for Bell D-188A, but never officially assigned

      Unofficial designations YF-112 and up were later assigned to "black" projects - see Fighter series in Unified System.

      [edit] Fighter, Multiplace

      [edit] Pursuit, Biplace

      [edit] Observation

      [edit] Observation, 1924-1942

        - Curtiss - Douglas - Dayton-Wright - Martin - Douglas - Thomas-Morse - Douglas - Douglas - Douglas - Loening - Curtiss - Curtiss - Curtiss - Douglas - Keystone - Curtiss - Consolidated - Curtiss - Thomas-Morse - Thomas-Morse - Thomas-Morse - Douglas - Thomas-Morse - Curtiss - Douglas - Curtiss - Fokker - Vought - Douglas - Curtiss - Douglas - Douglas - Thomas-Morse - Douglas - Douglas - Douglas - Keystone - Douglas - Curtiss - Curtiss - Thomas-Morse - Douglas - Douglas - Douglas - Martin - Douglas - North American - Douglas - Stinson (redesignated L-1 in 1942) - Bellanca - Ryan - Curtiss - Douglas - Stinson - ERCO - Lockheed - Taylorcraft (redesignated L-2 in 1942) - Aeronca (redesignated L-3 in 1942) - Piper (redesignated L-4 in 1942) - Kellett - Pitcairn - Stinson (redesignated L-5 in 1942) - Interstate (redesignated XL-6 in 1942)

      [edit] Observation amphibian, 1925-1948

        - Loening - Loening - Douglas - Douglas - Douglas
    • OA-6 - Consolidated
    • OA-7 - Douglas - Sikorsky - Grumman - Consolidated - Sikorsky - Grumman - Grumman - Grumman - Republic
    • [edit] Liaison, 1942-1962

        - Stinson - Taylorcraft - Aeronca - Piper - Stinson - Interstate - Universal Aircraft - Interstate - Stinson - Ryan - Bellanca - Stinson - Stinson/Convair - Piper - Boeing - Aeronca - North American/Ryan - Piper - Cessna - de Havilland Canada - Piper - Ryan - Beechcraft - Helio - McDonnell - Aero Design - Cessna - Helio

      [edit] Reconnaissance

      [edit] Photographic reconnaissance, 1930-1948 / Reconnaissance, 1948-1962

        - Fairchild - Beechcraft - Douglas - Lockheed - Lockheed - North American - Consolidated - de Havilland - Boeing - North American - Hughes (redesignated XR-11 in 1948) - Republic (redesignated XR-12 in 1948) - Boeing - Lockheed - Northrop - Boeing

      [edit] Reconnaissance-strike, 1960-1962

      Both of the following aircraft are part of the B- (bomber) series.

      [edit] Rotary Wing, 1941-1948/Helicopter 1948-present

      Designated R- for "rotary wing" until 1948, when the United States Air Force was founded. After this, all R- designations were changed to H- ("helicopter"), but the original numbers were retained. After 1962, the series was continued within the Unified Designation System.

        - Platt-LePage - Kellett - Kellett - Sikorsky - Sikorsky - Sikorsky
      • R-7 - Sikorsky Kellett - Firestone
      • R-10/H-10 - Kellett
      • R-11/H-11 - Rotorcraft - Bell - Bell
      • R-14 - Firestone
      • R-15/H-15 - Bell - Piasecki - Hughes/Kellett - Sikorsky - Sikorsky - McDonnell - Piasecki - Kaman - Hiller - Seibel - Piasecki - American Helicopter - Piasecki - Hughes - McDonnell - McCulloch - Doman - Hiller - Bell (redesignated XV-3 in 1952) - Sikorsky - McDonnell (redesignated XV-1 in 1952)
        • H-36 - reserved for secret project LONG EARS
        • H-38 - reserved for secret project SHORT TAIL
        • H-44 - reserved for secret project BIG TOM
        • H-45 - reserved for secret project STEP CHILD
        • H-69 - skipped

        [edit] Supersonic/special test, 1946-1948

        The series was continued as the X (Experimental) series after 1948 - see X-series in Unified System.


        While the majority of the earlier versions and war weary aircraft would quickly be relegated to scrap, most of the last production blocks would continue in service with the post war USAAF and the new USAF. For the next 5 years, these aircraft would continue as a front line fighter with the active airforce. It would also serve for over 10 years with a preponderance of the National Guard fighter units east of the Mississippi River.

        The P-47 would also be the foundation stock for rebuilding a majority of the European post World War II airforces. Unlike the P-51, this aircraft was easily maintained and more forgiving of pilot mistakes (due to its more robust construction). Like the USAF these aircraft only started to retire as the second generation jets became readily available. In the early 1950s as the now renamed F-47 was being retired from active USAF service these aircraft were through various Military Assistance Programs (MAPS) offered to numerous South American countries. For the next 15 years, the P-47 would continue as a front line fighter with these nations.

        Unlike many of its contemporary WWII fighters, the P-47 was not a sought after aircraft on the post war civilian marketplace. It did not have the sleek lines needed for an executive aircraft or racing. For the next 22 years, except for 2 razorback versions, the P-47 would progressively diminish from the United States skies. It was only in 1968 with the retirement of the Peruvian Air Force's P-47s and the successful importation of 6 aircraft would the population of these aircraft begin to grow. During the late 1970s and early 1980s more airframes would be returned from numerous South American countries for restoration and display. In the late 1980s aircraft from Yugoslavia were also rediscovered and imported. The current batches of P-47s to return to the restored are those long forgotten wartime crash sites.


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