What about a turbocharged P36?

[pinsog]

We all know the P39 and P40 never received a turbocharger making both of them a dog above 15,000 feet or so. The P35 was never a good performer, poor handling/turning ability and poor workmanship (leaking wing tanks). But the P35 got a turbocharger and became the P43 Lancer with good performance at the time of 350 mph plus and 1200 hp at 25,000 feet while still retaining poor handling and poor workmanship.

The P36 on the other hand, had an excellent climb rate and exceptional maneuverability. What about installing either a Wright 1820 or P&W 1830 with a turbocharger in the P36? It would gain some weight but still shouldn't weigh as much as a P40 or F4F Wildcat and still have 1200 hp at 25,000 feet. Should still retain much of its handling, certainly no worse than the P40 which still turned well, should still out climb a P40 or Wildcat rather easily and do at least 350 mph plus (I would think it would be faster than a P43 Lancer) putting it on a level footing with the Spitfire and ME109 and Zero.

Thoughts?

 

[GregP]

You are the first person I have ever heard mention poor workmanship in a Seversky aircraft. We happen to fly one, a 2-PA / AT-12, and the workmanship is very good. It was basically a 2-seat P-35.

The P-35 didn't have self-sealing tanks, but I haven't heard much about leaks other than when they were strafed by Japanese aircraft. Without self-sealing tanks, that is to be expected.

Perhaps you could tell me the source of the "poor workmanship" claim?

 

[FLYBOYJ]

The P35 was never a good performer, poor handling/turning ability and poor workmanship (leaking wing tanks)

The P-35 represented a first generation all-metal monoplane fighter. The overall workmanship of the over all aircraft was excellent (I've seen one up close), it did have a wet wing, and if you ever worked around one, they all leak! I read varying articles about this aircraft but very few from someone who actually flew one. No doubt the P-35 was obsolete by the time the war started. Where did you get this assessment for this aircraft?!?!

 

[FLYBOYJ]

Wow Greg, we're psychic friends!!!

 

[pinsog]

Perhaps I should retract or rephrase the 'poor workmanship' comment. I have seen multiple sources on the P35 and especially the P43 Lancer having leaking fuel tanks. The AVG turned down the P43 due to leaking fuel tanks. As I understand it, wasn't it a wet wing without actual tanks?

 

[pinsog]

I guess our post crossed in space. So all wet wings leak…learned something new today. Wonder why they would do such an arrangement on a fighter plane that gets shot at??? Where did I get assessment on P35? Multiple places. Everything I have read (admittedly much of it was in cyber space) including just the specs showed it to be slow, poor climbing and poor turning.

 

[FLYBOYJ]

I guess our post crossed in space. So all wet wings leak…learned something new today. Wonder why they would do such an arrangement on a fighter plane that gets shot at??? Where did I get assessment on P35? Multiple places. Everything I have read (admittedly much of it was in cyber space) including just the specs showed it to be slow, poor climbing and poor turning.

By what standards? During the 1930s it was state of the art, by 1940 it was "slow, poor climbing and poor turning." I could compare a P-51 to an F-15 and make the same assessment!

There's a book about Alexander de Seversky and it tells all about the P-35.

 

[pinsog]

By what standards: I would compare it directly to the P36 since they were designed at the same time and the P35 comes off very poorly except in range.


Specifications (P-35A)[edit]
Data from The American Fighter[34]
General characteristics

Crew: One
Length: 26 ft 10 in (8.17 m)
Wingspan: 36 ft 0 in (10.97 m)
Height: 9 ft 9 in (2.97 m)
Wing area: 220 ft² (20.43 m²)
Empty weight: 4,575 lb (2,075 kg)
Loaded weight: 6,118 lb (2,775 kg)
Max. takeoff weight: 6,723 lb (3,050 kg)
Powerplant: 1 × Pratt Whitney R-1830-45 Twin Wasp radial engine, 1,050 hp (783 kW)
Performance

Maximum speed: 290 mph (252 knots, 467 km/h) at 12,000 ft (3,660 m)
Cruise speed: 260 mph (226 knots, 418 km/h)
Range: 950 mi (826 nmi, 1,530 km)
Service ceiling: 31,400 ft (9,570 m)
Rate of climb: 1,920 ft/min (9.8 m/s)
Wing loading: 27.8 lb/ft² (135.8 kg/m²)
Power/mass: 0.172 hp/lb (0.282 kW/kg)

Specifications (P-36A)[edit]
Data from Curtiss Fighter Aircraft: A Photographic History 1917-1948[24]
General characteristics

Crew: 1
Length: 28 ft 6 in (8.7 m)
Wingspan: 37 ft 4 in (11.4 m)
Height: 8 ft 5 in (2.6 m)
Wing area: 235.94 ft² (21.92 m²)
Empty weight: 4,567 lb[25] (2,076 kg)
Loaded weight: 5,650 lb (2,560 kg)
Max. takeoff weight: 6,010 lb[25] (2,732 kg)
Powerplant: 1 × Pratt Whitney R-1830-17 Twin Wasp air-cooled radial piston engine, 1,050 hp (783 kW)
Performance

Maximum speed: 313 mph (272 knots, 500 km/h) at 8,500 ft, 2,960 m
Cruise speed: 270 mph (235 knots, 432 km/h)
Range: 625 mi (543 nmi, 1,006 km) at 270 mph (419 km/h), 860 mi (748 nmi, 1,385 km) at 200 mph
Service ceiling: 32,700 ft (9,967 m)
Rate of climb: 3,400 ft/min (17 m/s)
Wing loading: 23.9 lb/ft² (116.8 kg/m²)
Power/mass: 0.186 hp/lb (306w/kg)

These are from Wiki, I know I know, but anyway, the P36 beats the P35 rather badly on everything but range. But, when a turbocharger was added to the P35, its performance up high was better than anything the US had at the time except for the P38. So, what if they had installed the same turbocharged engine in the P36 with its exceptional handling and climb rate? Would a turbocharger and the plumbing fit in a P36?

 

[GregP]

The only person I know who flies a Seversky semi-regularly is John Maloney and I've asked him about the AT-12 / 2-PA we have. He loves it and says it climbs and flies very well / handles beautifully, but is a bit slow compare with the WWII fighters. That is to be expected with a 975 HP engine in an airframe that was upsized a bit and give a pot belly to house the air and exhaust ducting for the supercharger to become the P-47 with 2,000 HP.

As for the P-36, it is one of my favorites of the time. It is definitely supposed to handle far better than a P-40.

 

[pinsog]

Greg, could the turbocharger and plumbing from a P43 Lancer be put into the P36 airframe? Or is it too small?

 

[GrauGeist]

Keep in mind that while the P-36 was a great performer, it also was lacking self-sealing tanks and suitable cockpit armor.

It was also lightly armed, with 1 .30 MG and 1 .50 MG, although later models were a little better equipped, with twin .50 MG in the cowl and 2 (or 4) .30 MGs in the wings.

So adding a supercharger wouldn't do much good unless you added the armor and self-sealing tanks...and now you're in the league of the P-40, weight-wise.

 

[pinsog]

Keep in mind that while the P-36 was a great performer, it also was lacking self-sealing tanks and suitable cockpit armor.

It was also lightly armed, with 1 .30 MG and 1 .50 MG, although later models were a little better equipped, with twin .50 MG in the cowl and 2 (or 4) .30 MGs in the wings.

So adding a supercharger wouldn't do much good unless you added the armor and self-sealing tanks...and now you're in the league of the P-40, weight-wise.

Agree that the weight would go up and quite possibly match the P40. BUT you would also have 1200 hp up to 25,000 feet. Pilot would definitely need a sheet of armor behind his seat and head, self sealing tanks, weapons: Against Japan I would give it 2 synchronized 50's. If it fought against Germany either 2 synchronized 50's and 1 50 in each wing, or 4 50's in the wing and no fuselage guns. What I wouldn't do is weight it down with 6 50's like they did the F4F4 Wildcat and later P40's.

Back to my other question: Would the same turbo charger setup the P43 used fit in the P36? Or is the P36 too small?

(glad you responded GrauGeist, didn't you say your uncle flew P36's?)

 

[GrauGeist]

Agree that the weight would go up and quite possibly match the P40. BUT you would also have 1200 hp up to 25,000 feet. Pilot would definitely need a sheet of armor behind his seat and head, self sealing tanks, weapons: Against Japan I would give it 2 synchronized 50's. If it fought against Germany either 2 synchronized 50's and 1 50 in each wing, or 4 50's in the wing and no fuselage guns. What I wouldn't do is weight it down with 6 50's like they did the F4F4 Wildcat and later P40's.

Back to my other question: Would the same turbo charger setup the P43 used fit in the P36? Or is the P36 too small?

(glad you responded GrauGeist, didn't you say your uncle flew P36's?)

The R-1830-17 of the P-36 was going to be slightly different than the R-1830-49 of the P-43. The supercharger would require quite a bit of additional space, too.

And yes, my Uncle was assigned the P-36, but was never able to use it in combat.

 

[GregP]

I think it could be put in but, rather than add bumps and bad aerodynamic things, I'd probably opt to add a short fuselage plug with enough space for it. Sort of a short plug behind the engine while trying to keep the pilot as far forward as possible. If you were to add it behind the pilot, you'd probably need a pot belly like the P-47 for all the ducting.

It could probably easily be worked out today but with 1938 technology, I'm not sure the result would be as good as it might be otherwise. It would likely be better than the P-43, though. I would love to have seen a turbocharged P-36 with an R-2000 in it.

Conversely, it would have been nice to actually build and fly a turbocharged P-40, too. I have often wondered if an increase power at altitude would have made the P-40 a contender of some merit, particularly an XP-40Q that might have morphed into a production P-40Q.

Of the two, I think offhand that the P-36 would probably have been easier to debug and get into service in a timely fashion, but could be wrong.

 

[FLYBOYJ]

By what standards: I would compare it directly to the P36 since they were designed at the same time and the P35 comes off very poorly except in range.


Specifications (P-35A)[edit]
Data from The American Fighter[34]
General characteristics

Crew: One
Length: 26 ft 10 in (8.17 m)
Wingspan: 36 ft 0 in (10.97 m)
Height: 9 ft 9 in (2.97 m)
Wing area: 220 ft² (20.43 m²)
Empty weight: 4,575 lb (2,075 kg)
Loaded weight: 6,118 lb (2,775 kg)
Max. takeoff weight: 6,723 lb (3,050 kg)
Powerplant: 1 × Pratt Whitney R-1830-45 Twin Wasp radial engine, 1,050 hp (783 kW)
Performance

Maximum speed: 290 mph (252 knots, 467 km/h) at 12,000 ft (3,660 m)
Cruise speed: 260 mph (226 knots, 418 km/h)
Range: 950 mi (826 nmi, 1,530 km)
Service ceiling: 31,400 ft (9,570 m)
Rate of climb: 1,920 ft/min (9.8 m/s)
Wing loading: 27.8 lb/ft² (135.8 kg/m²)
Power/mass: 0.172 hp/lb (0.282 kW/kg)

Specifications (P-36A)[edit]
Data from Curtiss Fighter Aircraft: A Photographic History 1917-1948[24]
General characteristics

Crew: 1
Length: 28 ft 6 in (8.7 m)
Wingspan: 37 ft 4 in (11.4 m)
Height: 8 ft 5 in (2.6 m)
Wing area: 235.94 ft² (21.92 m²)
Empty weight: 4,567 lb[25] (2,076 kg)
Loaded weight: 5,650 lb (2,560 kg)
Max. takeoff weight: 6,010 lb[25] (2,732 kg)
Powerplant: 1 × Pratt Whitney R-1830-17 Twin Wasp air-cooled radial piston engine, 1,050 hp (783 kW)
Performance

Maximum speed: 313 mph (272 knots, 500 km/h) at 8,500 ft, 2,960 m
Cruise speed: 270 mph (235 knots, 432 km/h)
Range: 625 mi (543 nmi, 1,006 km) at 270 mph (419 km/h), 860 mi (748 nmi, 1,385 km) at 200 mph
Service ceiling: 32,700 ft (9,967 m)
Rate of climb: 3,400 ft/min (17 m/s)
Wing loading: 23.9 lb/ft² (116.8 kg/m²)
Power/mass: 0.186 hp/lb (306w/kg)

These are from Wiki, I know I know, but anyway, the P36 beats the P35 rather badly on everything but range. But, when a turbocharger was added to the P35, its performance up high was better than anything the US had at the time except for the P38. So, what if they had installed the same turbocharged engine in the P36 with its exceptional handling and climb rate? Would a turbocharger and the plumbing fit in a P36?

I think you need to make the comparison to the original Hawk 75 and the AP-1 during the 1936 competition between the two aircraft. This is mentioned in the book about de Seversky. I also found this;

"When the design was first offered to the Army on May 24, 1935, three different power plants were proposed, and the prototype actually experienced four engine changes within a year's testing. For the generous 236-square-foot area wing, a new NACA 2300-series airfoil was chosen, with less drag than the Clark CHY profile used by Seversky. Using a unique retractable landing gear whose wheels rotated as they folded back flat within the wings, the Model 75 had a 700-hp Wright XR-1510-C5 when test pilot H. Lloyd Child made the first flight on May 13, 1935.

Top speed was estimated as a modest 253-mph at 10,000 feet, but this experimental radial engine was replaced in July by a 775-hp Wright XR-1670-5, which promised 263 mph. Neither of these power plants was accepted for Air Corps production, so another air-cooled radial, the 750-hp Pratt Whitney R-1535 adopted by the Army for attack and observation planes, powered the Curtiss Model 75 when it appeared on August 7 for the Army competition.

The larger Wright R-1820 on Seversky's entry gave it an advantage in speed. When Curtiss complained, the Secretary of War set back the contract competition to April 15, 1936. Don Berlin's Hawk was flown again as Model 75B on April 4, 1936, powered by an 850-hp single-row Wright XR-1820-G5 Cyclone, and with indentations behind the cockpit to help visibility. Curtiss estimated the top speed of their Hawk as 294 mph with the Cyclone, or 297 mph if provided with a Twin Wasp, but only 285 mph was actually obtained during the tests.

Although Seversky won the Fiscal 1936 contract, Curtiss did get an order on August 7, 1936, for three Y1P-36s. The first Y1P-36, was delivered to Wright Field with a twin-row Pratt Whitney R-1830-13 and Hamilton propeller on March 4, 1937, and was soon followed by its two service test companions. The gear-driven supercharger built into the back of the R-1830-13 yielded 1,050-hp for takeoff and 900-hp at 12,000 feet with 92-octane fuel, giving the Y1P-36 a top speed of 295 mph.

Fiscal 1938 funds would allow purchase of about 220 new pursuits, so both companies tried again with bids opened April 2, 1937. Specification 98-605 called for 300-mph and deleted the old bomb rack requirement; the Air Corps then didn't want its fighters diverted to ground- attack work.

Seversky offered its AP-1 at $15,900 each, while Curtiss wanted $18,720 for its P-36. This time the lowest bidder lost. Curtiss won the largest fighter contract since 1918: for 210 P-36s on July 30, 1937."

P-35 to P-42 by Ray Wagner - Page 1

 

[tomo pauk]

The proposed turboed P-36 would be the interesting thing. The P-36 have had 'normal' fuel tanks, so one of the shortcomings of the P-35 (and F2A, for that matter) would've not surfaced. It is a question of whether the turbo intercooler will be reasonably blended in the airframe, to keep the drag manageable. The fuselage tank (then was named 'overload fuel tank') would lost much of it's capacity if the turbo is located behind the pilot, but that should not be that a great problem.

 

[pinsog]

FLYBOY, do you have any information on how well the P35 turned compared to the P36? Or how the P35 turned and climbed in general?

GregP, I agree that packaging the turbo immediately behind the engine, all in front of the pilot might be preferable, just lengthen the nose. GregP, was it you that said somewhere else on this forum that Curtis proposed a 1200 hp 2 speed, 2 stage P&W for the P36 with a 355 MPH top speed?

GregP and FLYBOY, you both work on these things, I don't. With 70 years of hindsight, would you go for a turbocharged P36? Or a 2 speed, 2 stage P36? I just personally think the P40 was a step backward for the US at the time. It did gain some speed, but it lost turning ability, climb, its altitude performance was bad and it was always slower than a P39. I think continued development of the P36 would have been the way to go, especially against the Japanese.

 

[tomo pauk]

The turbo immeditely behind the engine won't work on the state of the art in the USA during the ww2; one needs air cooled turbne blades to help out. The 2-stage P-36 would be interesting, if a bit too late vs. P-40. Leading us to the P-40s main quality - being in volume production when needed. BTW, the 'some speed' gain vs. P-36 was 50 mph, a major improvement in anybody's book.

The P-40 was no push over vs. Japanese aircraft, especially the Army types like the Ki 27 or Ki 43. Adding the self sealing fuel tanks, pilot protection and heavy armament and the required airframe strength will limit the performance of any P-36, with with any type of supercharging.

 

[FLYBOYJ]

I've read somewhere that the P-35 was too harmonized for a fighter. The link I provided has a quote from Charles Lindberg that quoted him saying that the P-36 "was a better flying aircraft." Aside from that that's about all I heard about the P-35, but you could look at it's power to weight ratio and wing loading and draw your own conclusions.

With hindsight being 20-20, I think a two-stage blower would have been a better option in lieu of a turbocharger, considering engineering resources available at the time. As fighter airframe development was moving along pretty quickly during that period, some technologies like aviation turbos and superchargers were just catching up, and also remember, all this development had to be undertaken with depression-era dollars. Lastly you had some builders and military planners who were not visionaries and there were many obsolete concepts attempted during the same period that squandered away time and money - I think the Bell XFM Airacuda was the poster child of this situation.

 

[GrauGeist]

The P-35 may have had some potential, but the airframe wasn't "clean" by virtue of it's design.

The "greenhouse" cockpit, the maingear stowage and other factors all created a good deal of drag.