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]

Originally Posted by 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.

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]

Originally Posted by 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.

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]

Originally Posted by 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?

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]

Originally Posted by gjs238

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]

Originally Posted by 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.

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