USAAC/AAF being much improved in 1938-42?

[pinsog]

True enough, but here's a little known fact (to pilots, but not to mechanics): statistically, the same engine installed on twins has higher failure rates than on singles. And a single with engine out is much easier to ditch safely than a twin suffering from asymmetric thrust.
Cheers,
Wes

I see your point, but, as a fighter pilot I would be much more concerned about getting shot down by a Zero in a plane with much inferior performance like an F4F-4 than I would having an engine quit in the last 30-45 second window of no recovery while landing on a carrier (although absolutely no doubt it would have happened). On the other hand, many lives would have been saved by new pilots getting in trouble with a Zero and actually having multiple escape plans in my mythical F5F, (outrun, outcimb, out dive) or even returning on one engine if the other quit or had battle damage, or a prop seizing up (a real problem on early F4F-4's) or not running out of fuel.

But I still admit I would have to be a time traveler to talk the Navy into going from an F3F biplane to something as 'radical' as a turbocharged F5F, it simply wasn't going to happen.

 

[tomo pauk]

I don't think there would be any room for turbochargers in an A20 nacelle, the Allison's would take up most, if not all the room.

There was a turbocharged A-20, with turboes and intercoolers in the nacelle. (page 24)

But, for a low level attack plane like the A20, you wouldn't need turbochargers. Below 15,000 feet and especially below 10,000 feet you would be able to get about all the boost you need, a P40N was putting out 1480 hp at 10,550 feet. With the reduction in drag by going to an Allison engine along with 1480 hp per side, your A20 should be smoking fast. I don't think a Zero could come anywhere close to catching it. I think it's a good idea.

If we discard whole turbo idea, I'd probably go with the light DB7 airframe as a base, since the V-1710 was barely breaking 1100 HP line before 1941. Turboed V-1710s were a bit more powerful than non-turboed.

 

[Kevin J]

I see your point, but, as a fighter pilot I would be much more concerned about getting shot down by a Zero in a plane with much inferior performance like an F4F-4 than I would having an engine quit in the last 30-45 second window of no recovery while landing on a carrier (although absolutely no doubt it would have happened). On the other hand, many lives would have been saved by new pilots getting in trouble with a Zero and actually having multiple escape plans in my mythical F5F, (outrun, outcimb, out dive) or even returning on one engine if the other quit or had battle damage, or a prop seizing up (a real problem on early F4F-4's) or not running out of fuel.

But I still admit I would have to be a time traveler to talk the Navy into going from an F3F biplane to something as 'radical' as a turbocharged F5F, it simply wasn't going to happen.

Against the Japanese, you only need the performance of the Wildcat in 1941/42, so no F5F. However, the Brits need that sort of speed in the Med, even the Seafire IIc wasn't fast enough. A handful of F5F's on each USN carrier as a deck park would have been useful to handle the D4Y before the Corsair and Hellcat entered Service.

 

[pinsog]

There was a turbocharged A-20, with turboes and intercoolers in the nacelle. (page 24)



If we discard whole turbo idea, I'd probably go with the light DB7 airframe as a base, since the V-1710 was barely breaking 1100 HP line before 1941. Turboed V-1710s were a bit more powerful than non-turboed.

Agreed on all of that. Only thing is the turbocharged A20 has radials, an Allison is longer and has radiators etc where a radial is short and sort of hangs off the front of the nacelles leaving more room. I believe the sole reason for the P38 twin booms was to have enough room for all the turbocharger stuff to go.

 

[pinsog]

Against the Japanese, you only need the performance of the Wildcat in 1941/42, so no F5F. However, the Brits need that sort of speed in the Med, even the Seafire IIc wasn't fast enough. A handful of F5F's on each USN carrier as a deck park would have been useful to handle the D4Y before the Corsair and Hellcat entered Service.

I would have to disagree that the Wildcat performance was enough in 1942. I believe the loss of the Lexington and Yorktown and possibly the Hornet were all a direct result of the Wildcat not being up to snuff, although I'll admit it did well considering it's opponnent. A turbocharged F5F that weighed 2500 pounds less than a P38 (around 12,000 pounds if the wing tanks I added were empty vs 14,500 for a P38) and had 1200 hp per engine instead of 1150 like an early P38 should have had an amazing climb rate, speed about the same, dived well etc. I think it would have had the speed, dive and climb to avoid Zero escorts while butchering any Japanese bombers. Wildcats always had a field day with bombers if there were no Zeros to interfere.

I agree it would have been great for the Royal Navy as well. Add dive brakes and it could dive bomb. Should also be able to carry a torpedo (Hellcats, Corsairs and P38's all could although they didn't) I think the RN could literally have put 1 airplane type on a carrier that did it all. If they needed a bit more weight lifting ability or slower landing speed then they could have added a bit more wingspan.

 

[tomo pauk]

I would have to disagree that the Wildcat performance was enough in 1942. I believe the loss of the Lexington and Yorktown and possibly the Hornet were all a direct result of the Wildcat not being up to snuff, although I'll admit it did well considering it's opponnent.
...

Agreed pretty much.

Agreed on all of that. Only thing is the turbocharged A20 has radials, an Allison is longer and has radiators etc where a radial is short and sort of hangs off the front of the nacelles leaving more room. I believe the sole reason for the P38 twin booms was to have enough room for all the turbocharger stuff to go.

We're still left with a nice, wide nacele to put the turbo anciliaries in it.

 

[pinsog]

[We're still left with a nice, wide nacele to put the turbo anciliaries in it.[/QUOTE]

If it would fit, I'm a big fan of turbochargers on about anything.

I would like to have seen a turbocharger on an F4F-3 Wildcat. IF they could have mounted it and the intercooler right behind the engine. I would have used a Wright 1820 to save weight, then put the turbocharger and intercooler between the engine and firewall.

The problem is, others have wondered if the exhaust gases would be too hot with the turbocharger being mounted that close to the engine. If not, that would have made a nice little power egg setup and with 1200 hp from sea level to 25,000 it would be a nice increase in speed as well

 

[tomo pauk]

I would like to have seen a turbocharger on an F4F-3 Wildcat. IF they could have mounted it and the intercooler right behind the engine. I would have used a Wright 1820 to save weight, then put the turbocharger and intercooler between the engine and firewall.

The problem is, others have wondered if the exhaust gases would be too hot with the turbocharger being mounted that close to the engine. If not, that would have made a nice little power egg setup and with 1200 hp from sea level to 25,000 it would be a nice increase in speed as well

Grumman loved to install fuel tanks in fuselage bottom, that is great for CoG reasons, and from weight of the tank reasons. What could be done is to have two fuel tanks installed in the wings, and delete the fuselage fuel tanks? Leaves a lot of room for turbo.
On the other hand, there is no appreciable thrust surplus under 20000 ft vs. a 2-stage R-1830, and weight is bound to go up a bit.

All in all, the alternative USN aircraft deserve a separate thread

 

[Kevin J]

I would have to disagree that the Wildcat performance was enough in 1942. I believe the loss of the Lexington and Yorktown and possibly the Hornet were all a direct result of the Wildcat not being up to snuff, although I'll admit it did well considering it's opponnent. A turbocharged F5F that weighed 2500 pounds less than a P38 (around 12,000 pounds if the wing tanks I added were empty vs 14,500 for a P38) and had 1200 hp per engine instead of 1150 like an early P38 should have had an amazing climb rate, speed about the same, dived well etc. I think it would have had the speed, dive and climb to avoid Zero escorts while butchering any Japanese bombers. Wildcats always had a field day with bombers if there were no Zeros to interfere.

I agree it would have been great for the Royal Navy as well. Add dive brakes and it could dive bomb. Should also be able to carry a torpedo (Hellcats, Corsairs and P38's all could although they didn't) I think the RN could literally have put 1 airplane type on a carrier that did it all. If they needed a bit more weight lifting ability or slower landing speed then they could have added a bit more wingspan.

You're not going to get many F5F's until the second half of 1942, certainly not turbo supercharged ones. You may have a handful on board what's left of your carriers in the second half of 1942. Testing wasn't resumed with the final mods until January 1942. So assuming a 6 month delay before service intro the it's not going to be ready for Midway, so you're looking at Guadalcanal and the Battle of Santa Cruz, so you're looking at a squadron on maybe each on Sarratoga, Hornet, Enterprise and Wasp if you're lucky. Also you're going to have to subcontract it as Grumman has too much work on its hands, so perhaps Brewster for the USN, so no Buccaneers or Corsairs from them, and for the FAA use Fairchild Canada and CC&F, so no Helldivers.

 

[pinsog]

I'd put the turbocharger with the engine up front, so it would be engine, intercooler, turbocharger as a power egg. Guns are in the wings so I don't think fuel could go there as well.
Run the numbers on increased speed:
5,500 feet 295 mph on 1050 hp
308 mph on 1200 hp

13,000 feet 313 mph on 1000 hp
332 mph on 1200 hp

19,000 feet 330 mph on 1000 hp
350 mph on 1200 hp

Climb would increase as well. There is about a 200-250 pound difference between a Wright 1820 and a 2 stage P&W 1830 not including intercooler so I think weight would stay about the same.

 

[pinsog]

You're not going to get many F5F's until the second half of 1942, certainly not turbo supercharged ones. You may have a handful on board what's left of your carriers in the second half of 1942. Testing wasn't resumed with the final mods until January 1942. So assuming a 6 month delay before service intro the it's not going to be ready for Midway, so you're looking at Guadalcanal and the Battle of Santa Cruz, so you're looking at a squadron on maybe each on Sarratoga, Hornet, Enterprise and Wasp if you're lucky. Also you're going to have to subcontract it as Grumman has too much work on its hands, so perhaps Brewster for the USN, so no Buccaneers or Corsairs from them, and for the FAA use Fairchild Canada and CC&F, so no Helldivers.

Like I said, it would have to be the F5F INSTEAD of the Wildcat not in addition to the Wildcat. I agree with your timeline if the F5F were done in addition to the Wildcat. In my fantasy world, the Wildcat never existed.

 

[tomo pauk]

A stab at alternative B-26? Or let's have Martin make a 4-engined bomber powered with R-2800s?

 

[Kevin J]

Like I said, it would have to be the F5F INSTEAD of the Wildcat not in addition to the Wildcat. I agree with your timeline if the F5F were done in addition to the Wildcat. In my fantasy world, the Wildcat never existed.

In the real World, its going to take you 2 years from first flight to the first F5F's rolling off the production line so you still need the Wildcat. I do like the F5F, it was a missed opportunity.

 

[pinsog]

In the real World, its going to take you 2 years from first flight to the first F5F's rolling off the production line so you still need the Wildcat. I do like the F5F, it was a missed opportunity.

I have the book on the F5F and I think they dragged their feet from the beginning because they were overwhelmed. I personally think they should have had a flying prototype a year earlier and in production a year after that, but we will never know. I also know they would have NEVER used turbochargers either, but even 2 speed P&W 1830-33's should have been a big increase in speed with 7 square feet less frontal area than the Wright 1820's and 1200 hp up to 5,000 feet and 1,000 hp up to 14,500 feet instead of 1000 hp up to 4,500 feet and 900 hp up to 14,000

 

[Kevin J]

I have the book on the F5F and I think they dragged their feet from the beginning because they were overwhelmed. I personally think they should have had a flying prototype a year earlier and in production a year after that, but we will never know. I also know they would have NEVER used turbochargers either, but even 2 speed P&W 1830-33's should have been a big increase in speed with 7 square feet less frontal area than the Wright 1820's and 1200 hp up to 5,000 feet and 1,000 hp up to 14,500 feet instead of 1000 hp up to 4,500 feet and 900 hp up to 14,000

Same sort of power as the Whirlwind. It would have made an impressive interceptor of kamikaze aircraft even in 1945 with upgraded R-1820's operated from carriers. Ideal for the RN in the Med, better than the Seafire. Capable of intercepting the D4Y in 1942.

 

[pinsog]

Same sort of power as the Whirlwind. It would have made an impressive interceptor of kamikaze aircraft even in 1945 with upgraded R-1820's operated from carriers. Ideal for the RN in the Med, better than the Seafire. Capable of intercepting the D4Y in 1942.

If you want it for the Royal Navy, what about hanging a pair of Merlin's on it? I have no idea about the weight of a Merlin and radiator compared to a Wright, but drag would be much less, vision would be much better and power would be out of this world. Chin radiators so you could change out the whole unit quickly if battle damaged leaving the entire internal wing for fuel

 

[tomo pauk]

Something like F5F, but with V12 (Merlin, V-1710) makes a lot of sense for the USAAC/AAF.

 

[pinsog]

There were no two stage Wright R-1820s that were mechanically driven (at least not that made it to production). I have not seen anything about a planned two stage engine at this point in the war although one might have been planned.
I have no idea why they would move the heavier R-1820 engines further forward than the R-1535 engines.

I would also note that you need bigger intercoolers for 1200hp at 25,000ft than you do for 1200hp at 20,000ft let alone 1000hp at 19,000ft like the F4F. The air is thinner so you need more volume for the same mass/weight and you have to compress the air more making it hotter to get the same manifold pressure.

As for the fuel tanks, a lot depends on the actual shape of the tank, flat tanks weigh more than deep tanks, self sealing material was heavy, SPD needed 218lbs to change from unprotected out tanks to protected tanks. It took 232lbs to protect the main tanks. I don't know what the unprotected tanks weigh.

I found some pics of the Grumman XP50
Are those flat things on the side behind the engine intercoolers?

 

[pinsog]

Something like F5F, but with V12 (Merlin, V-1710) makes a lot of sense for the USAAC/AAF.

What about this with a pair of Merlins? 4 50's, 250 gallons of fuel in original tank, 75 gallon outer wing tanks, totaling 400 gallons internal. 8 feet shorter and 10 feet less wingspan than a P38, not sure total weight.

Picture the head on look with Merlin's on it. Talk about drag reduction, there isn't much to this thing.

 

[Shortround6]

I found some pics of the Grumman XP50
Are those flat things on the side behind the engine intercoolers?

I don't know for sure but if they are where are the inlets and outlets?

Intercooler intake duct on an F4F-4

Intercooler from the rear on F4F-3

Intercooler is the thing with all the fins. On the F4F the cooling air went through the ducts (one on each side) through the intercoolers and was dumped (exhausted) into the wheel well/s to find it's way out past the wheels/tires. Note th ducting on top of and below the intercooler that bring the charge/combustion air from the aux supercharger to the main supercharger. FM-2s did not use intercoolers.
and F4F-3 showing the inlets inside the cowl.

I would think if you put intercoolers where the boxes are on the XP-50 you have some problems.1, Like you want fresh/cool air flowing through the intercooler, not air that has been heated by the engine. 2, you want a way to get rid of the air in the intercooler system, a vent or flap begenought to handle the airflow.
The XP-50 has an adjustable flap near the rear on the nacelle but I don't know if it is for the intercoolers or the turbo (or oil cooler?) or if there are any other adjustable flaps on the engine nacelle.

I Don't even know where the carb intake/s and oil cooler/s are on the XP-50.