What if: P-43 with R-2600?

[gjs238]

Would it have been possible, or feasible, if the P-43 with Pratt Whitney R-1830-SC2G engine were developed to accept the R-2600 as used in the B25 and other aircraft???

 

[Colin1]

The R-2600 was around 580lbs (263Kgs) heavier than the R-1830 so strengthening of the basic design and lengthening of the rear fuselage and/or ballast would have been necessary and would have increased your rated available take-off power from 1,200hp to 1,700 - 1,900hp depending on which variant of 2600 you are talking about. The 2600 had a 7" wider diameter than the 1830 so I don't know how you'd juggle that into the aerodynamic considerations.

Technically the P-43 came to the end of its development line pretty early on, it had a tendency to yaw quite badly on take-off and a more powerful engine would be unlikely to help this. By 1941, the USAAC felt it wasn't going to get much better than it already was and they were already looking at the P-47. About the only thing that kept the P-43 in it as long as it did were the delays in getting the R-2800 into production. As a result of these delays I think about 250'ish P-43s were built which is impressive as they didn't intend to build any.

It was fitted with a PW R-2180 but even that fell flat when compared to contemporary designs existing in Europe.

I'm just wondering what the gains would be with the additional weight from the powerplant and the airframe modifications due to strengthening, lengthening and ballast and thinking that compared to the promising P-47, the P-43 looked an evolutionary dead-end, whatever the powerplant.

 

[gjs238]

The R-2600 was around 580lbs (263Kgs) heavier than the R-1830 so strengthening of the basic design and lengthening of the rear fuselage and/or ballast would have been necessary and would have increased your rated available take-off power from 1,200hp to 1,700 - 1,900hp depending on which variant of 2600 you are talking about. The 2600 had a 7" wider diameter than the 1830 so I don't know how you'd juggle that into the aerodynamic considerations.

Technically the P-43 came to the end of its development line pretty early on, it had a tendency to yaw quite badly on take-off and a more powerful engine would be unlikely to help this. By 1941, the USAAC felt it wasn't going to get much better than it already was and they were already looking at the P-47. About the only thing that kept the P-43 in it as long as it did were the delays in getting the R-2800 into production. As a result of these delays I think about 250'ish P-43s were built which is impressive as they didn't intend to build any.

It was fitted with a PW R-2180 but even that fell flat when compared to contemporary designs existing in Europe.

I'm just wondering what the gains would be with the additional weight from the powerplant and the airframe modifications due to strengthening, lengthening and ballast and thinking that compared to the promising P-47, the P-43 looked an evolutionary dead-end, whatever the powerplant.

I agree with what you've written.

The P-47 and R-2800, however, ended up having a somewhat protracted development, which is why the P-43 was ordered into production in the first place. So the P-47 was not available for the "early" was years like the P-39 P-40.

I'm speculating what could have been done, developmentally, with the P-35, P-36, P-43 to have made them viable early war year contenders.
I'm not thinking about engine swaps, but development.

Developing the P-43 into the P-47 produced an amazing aircraft.

However, perhaps a smaller P-47/larger P-43 with the R-2600 could have entered service much sooner (?)
- Without the turbocharger it could have been a potent lower altitude machine better suited to ground attack/support than liquid-cooled engine planes.
- With a reliable turbocharger it could have been useful at high altitude, unlike other early war American fighters.

 

[Colin1]

So off the drawing board with a 2600 from the outset then
it could conceivably address one of the P-43's shortcomings, you would then need to address

i. poor manoeuverability
ii. lack of self-sealing fuel tanks
iii. pilot protection (armour)
iv. turbocharger reliability issues (might have been resolved with the move from the PW powerplant to the Wright powerplant)
v. 'wet' wing leakage issues that plagued the design

addressing these will affect the all-up weight of the a/c and potentially the range, if the wet wing issues cannot be resolved adequately.

 

[gjs238]

So off the drawing board with a 2600 from the outset then
it could conceivably address one of the P-43's shortcomings, you would then need to address

i. poor manoeuverability
ii. lack of self-sealing fuel tanks
iii. pilot protection (armour)
iv. turbocharger reliability issues (might have been resolved with the move from the PW powerplant to the Wright powerplant)
v. 'wet' wing leakage issues that plagued the design

addressing these will affect the all-up weight of the a/c and potentially the range, if the wet wing issues cannot be resolved adequately.

Right - but these were addressed with the development of the P-47.
I think the development of the R-2800 was the bottleneck in the development of the P-47.

A parallel development from the P-35/P-43 could have been the P-36.
The P-36 was developed from using the R-1830 into the Allison V-1710.
What if it had been developed into the R-2600 instead?

 

[Colin1]

Is it me or do you keep moving the goalposts?
Your original question was 'what if a/c a with engine a was developed to accept engine b?'

It seemed to become 'what if a/c a was developed with engine b from the outset?'

We now seem to have moved on to 'let's try a/c b with engine b'

I daresay lessons learned with the P-43 were incorporated into the P-47 design but the P-47 definitely replaced the P-43, rather than addressed its shortcomings. I wouldn't describe the issues with the R-2800 as a bottleneck but it certainly introduced delay into the program.

OK, so if I understand it correctly, we now stand at how would the P-36 have fared, fitted with the R-2600?

 

[gjs238]

Is it me or do you keep moving the goalposts?
Your original question was 'what if a/c a with engine a was developed to accept engine b?'

It seemed to become 'what if a/c a was developed with engine b from the outset?'

We now seem to have moved on to 'let's try a/c b with engine b'

I daresay lessons learned with the P-43 were incorporated into the P-47 design but the P-47 definitely replaced the P-43, rather than addressed its shortcomings. I wouldn't describe the issues with the R-2800 as a bottleneck but it certainly introduced delay into the program.

OK, so if I understand it correctly, we now stand at how would the P-36 have fared, fitted with the R-2600?

This isn't a debate, just a fun what if.
My original intention has not changed, but yes, the original question could have been better written.

I find it interesting to speculate on pre-war aircraft, such as the P-35, P-36, and P-43, following a different course of development with the benefit of hindsight.

It appears that the R-2800 wasn't fielded as soon as wished for.
The P-35 was developed into a turbocharged aircraft.
The P-36 was developed into a V-1710 aircraft.
The P-43 was developed into an even larger turbocharged aircraft with an engine whose development took longer than wished for.

If development had moved toward the R-2600, with and without turbo charging, might the result have been aircraft superior or equal to what was available in the early-war years?

 

[Colin1]

This isn't a debate, just a fun what if

It's both, isn't it?
I understand (and enjoy) the fun element of what-ifs, I just thought I was having difficulty nailing down the premise of this one

 

[Marshall_Stack]

Colin,

Could it be that you just had a problem with his New Jersey accent?

I enjoy post like these. I am always wondering the what-ifs of aircraft, especially for the early WWII designs.

 

[Colin1]

Colin,

Could it be that you just had a problem with his New Jersey accent?

I enjoy post like these. I am always wondering the what-ifs of aircraft, especially for the early WWII designs.

Could be
Me too, I hope he didn't take my comments the wrong way, I just couldn't quite nail down what was being asked

 

[Shortround6]

I agree with what you've written.

The P-47 and R-2800, however, ended up having a somewhat protracted development, which is why the P-43 was ordered into production in the first place. So the P-47 was not available for the "early" was years like the P-39 P-40.

I'm speculating what could have been done, developmentally, with the P-35, P-36, P-43 to have made them viable early war year contenders.
I'm not thinking about engine swaps, but development.

Developing the P-43 into the P-47 produced an amazing aircraft.

However, perhaps a smaller P-47/larger P-43 with the R-2600 could have entered service much sooner (?)
- Without the turbocharger it could have been a potent lower altitude machine better suited to ground attack/support than liquid-cooled engine planes.
- With a reliable turbocharger it could have been useful at high altitude, unlike other early war American fighters.

And From Colin 1:

"So off the drawing board with a 2600 from the outset then
it could conceivably address one of the P-43's shortcomings, you would then need to address

i. poor manoeuverability
ii. lack of self-sealing fuel tanks
iii. pilot protection (armour)
iv. turbocharger reliability issues (might have been resolved with the move from the PW powerplant to the Wright powerplant)
v. 'wet' wing leakage issues that plagued the design

addressing these will affect the all-up weight of the a/c and potentially the range, if the wet wing issues cannot be resolved adequately."

The problems with the turbo chargers may have been GE's fault and since they supplied ALL the turbo-chargers used on combat aircraft switching the basic engine may not get you very far. Problems with early B-17s (Wright engines) and P-38s (Allisons) in addition to the P-43 (P&W engines) doesn't give much hope that switching from the R-2800 to the R-2600 is going to solve the turbo problem.

Given the size and weight of the R-2600 any plane designed for it wasn't going to be that much smaller than P-47 (unless you halved the armament and reduced the range) so by the time you are done, while the P-43 upgrade is developed from the P-43 it actually would have next to 0% percent interchangeable parts, and delay the actual P-47 by a considerable period of time ( engineers and draftsmen can't work on two projects at once).

early war doctrine called for ground attack/ close support to be provided by attack planes. A-20s, A-24 (Dauntless), A-25 Helldiver (100 hundred ordered for the Army Dec of 1940) and so on.

 

[tomo pauk]

How this thread managed to dodge my attention...

 

[_PabloSniper_]

I suppose a change to the R-2000 would be easier.

 

[T Bolt]

If the P-43 had been designed with the R-2600 from the onset and it had been more of a success, we may have never seen the P-47, so it is probably a good thing it was not successful.

 

[Shortround6]

I suppose a change to the R-2000 would be easier.

Timing. The R-2000 was built after the R-2800. well after.
They built 1 R-2000 in July of 1941 then they built 8 in Dec 1941 and then a few dozen a month in 1942.
The R-2000 was planned as a fall back engine for transports using 87-91 octane fuel incase there were problems with 100-100/130 supplies.
The R-2000 was planed to give the same power as the R-1830 on lower octane fuel. Planned and actual use are not the same thing.
With 100/130 they could get more power than originally planned but that did not turn it into a fighter or even a combat engine. I don't think they ever planned to put them into B-24s or PBYs for instance.
Even in the planning stages the R-2000 was behind both the B series R-2800 and the BA series R-2600.

 

[tomo pauk]

If the P-43 had been designed with the R-2600 from the onset and it had been more of a success, we may have never seen the P-47, so it is probably a good thing it was not successful.

The P-43 that is, from day one, designed with the R-2600 would've been a much bigger aircraft than the historical P-43. Talk wing of 280-300 sq ft, empty weight of ~8000 lbs instead of ~6000 lbs, generous place for 6 .50s and the required ammo, as well as 250-300 gals of fuel instead of 200. The big turbo (C series) will be needed, the B series will be lacking here; more HP will also demand greater ducting for the air.
With 1500-1600 HP at 25000 ft, we'd probably have a 400 mph fighter by 1941 - not too shabby. Drop tanks by some time of 1942? Luftwaffe might not like that, not at all, ditto the Japanese.
For 1943, the R-2800-powered version might come in handy.

 

[Shortround6]

Timing gets a little weird.
The turbo AP-4 was at the 1939 fighter trials and as a result 13 planes were ordered in March 1939 as YP-43s. Engines were turbo R-1830s they expected the planes to be overweight.
Sept 1939 saw the army order 80 AP-4Js as P-44s with 1400hp turbo R-2180 engines and 6 machine guns. What kind of machine guns is usually not stated ( six .50s or a combination of .50s and .30s?) Also armor, BP glass and fuel tank protection is often not mentioned.
In the Spring of 1940 reports from Europe indicate that the P-44 won't be adequate when it show up.
Republic had been working on the AP-10/XP-47 which was a very small plane powered by an Allison engine and armed with two .50 cal guns but the Army in the fall of 1939 asked for more armament (four .30s) and few other changes. and the Army had ordered one in Nov 1939 and in Jan 1940 ordered a 2nd stripped version for early testing. But the Spring 1940 reports also showed this project would not meet future requirements and Kartveli submitted his ideas to the Army on June 12th 1940 and on Sept 5th 1940 the Army ordered the prototype XP-47B.
From Joe Baugher's website.
"One week later, on September 13, 1940, 773 production examples of the new fighter were ordered by the USAAC, 171 to be delivered as P-47Bs and 602 as P-47Cs. At the same time, the Army contract placed back in 1939 for 80 P-44 Rockets was cancelled. The contract was replaced with an order for a similar quantity of P-43 Lancers which would keep the Farmingdale production lines occupied pending the introduction of the new fighter."

So where does the R-2600 powered plane show up?
Again from Joe Baugher's website.
"The first YP-43s were delivered to the Army in September 1940........ The last YP-43 was delivered by April 1941, the type being given the name *Lancer*"
" The first P-43 was delivered on May 16, 1941, the last example being delivered on August 28, 1941."
"The P-43 was immediately followed by the P-43A, 80 examples of which were ordered. Serials were 40-2891/2970. Deliveries began in September of 1941."
On June 30, 1941, 125 further examples were ordered with Lend-Lease funds for supply to the Chinese Air Force, although their primary purpose was still to keep the Farmingdale production lines occupied until the Thunderbolt could be ready. The Chinese Lend-Lease P-43s were designated P-43A-1.
Production of the P-43A-1 was completed in March of 1942,"

and now for the P-47
" The first four P-47Bs from production (41-5896/5899) were delivered in mid-March of 1942"

Now how do you squeeze the R-2600 powered plane into that time line and what has to be changed/delayed to accommodate it.
Please remember that NONE of the P-43s were fully up to combat standards with full armor/BP glass and protected tanks. They had some but not all.

 

[tomo pauk]

Now how do you squeeze the R-2600 powered plane into that time line and what has to be changed/delayed to accommodate it.

If the P-43 is designed around the R-2600, the number of designs gets smaller, not bigger.
There is no P-44. No P-47A. No P-47B.

Please remember that NONE of the P-43s were fully up to combat standards with full armor/BP glass and protected tanks. They had some but not all.

Same as with the early P-39s, P-40s and P-38s.

 

[Shortround6]

If the P-43 is designed around the R-2600, the number of designs gets smaller, not bigger.
There is no P-44. No P-47A. No P-47B.


Same as with the early P-39s, P-40s and P-38s.

Basically somebody has to approve an R-2600 powered plane in 1938 or early 1939. Otherwise it won't get built in time.
An R-2600 powered plane, as you have noted in other places, is not going to be a P-35 with a new engine, unlike the P-43. You are going to need a new wing, fuselage and tail to go with the new landing gear.
What was Wright offering in the spring of 1939, maybe the two speed supercharger?
Was GE offering the C series turbo at the time?
And remember that Curtiss got the P-40 contract because the Army, while they desperately wanted turbos, didn't think they could get a turbo powered plane into squadron service until 1941. The YP-43 was placed holder or another experiment to further turbo knowledge.

With 1500-1600 HP at 25000 ft, we'd probably have a 400 mph fighter by 1941 - not too shabby.

The US barely got the P-38 and B-17 to work by the end of 1941. B-17 had a flight engineer to help handle things and it didn't change altitudes all that fast (climb or dive).
The turbo was big gamble.
For the P-43 it went in the YP-43s
The Pratt and Whitney R-1830-35 engine offering 1200 hp for takeoff and 1100-1200 hp at 20,000 feet.
the 1200hp at 25,000ft didn't show up until the -45 or -57 engines.
Which model turbo may be subject to question.

GE went through 12 different models of the Series B from the -1 to the -33( no idea where the missing numbers went) from the XP-38 to the P-38J and anything except the P-47s and few P-61s. So when did the C series turbo show up? Not promised but show up. B-29s used two B-11 turbos per engine.
The early B series turbos may not have moved enough air to supply 1500-1600hp at 25,000ft.

 

[tomo pauk]

Basically somebody has to approve an R-2600 powered plane in 1938 or early 1939. Otherwise it won't get built in time.
An R-2600 powered plane, as you have noted in other places, is not going to be a P-35 with a new engine, unlike the P-43. You are going to need a new wing, fuselage and tail to go with the new landing gear.

Agreed all the way.

What was Wright offering in the spring of 1939, maybe the two speed supercharger?
Was GE offering the C series turbo at the time?

The turboed R-2600 will need just the 1-speed supercharger, as per American fashion.
Seems like that Army gave the contract for the A-20 with the turboed engines on June 1939, after Douglas started the redesign of the 'basic' DB7 like the French were buying. See here, FWIW.
So someone in charge (or more of them), in that time (1st half of 1939) were sure that there will be a turbo for the R-2600 available for installation.

And remember that Curtiss got the P-40 contract because the Army, while they desperately wanted turbos, didn't think they could get a turbo powered plane into squadron service until 1941. The YP-43 was placed holder or another experiment to further turbo knowledge.

I certainly don't expect that the R-2600+turbo powered fighter will be an instant success, and already in 1941. What it might be is that it is an useful fighter in late 1941-early 1942, and that by another 6 months it is debugged and in mass production.