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Clay_Allison
Staff Sergeant
- 1,154
- Dec 24, 2008
I'm not really looking for weight, I'm looking for an engine with a better developed supercharger.
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While the Change from 12 to 11.5 might not be significant, changing armament to four .50s, adding armor and self sealing tanks and changing to a more powerful engine (or bigger supercharger) and bigger propeller would almost certainly change the load factors to a point where SOMETHING has to be done. I don't know how much extra weight would be involved but I would think that a Radial engine P-40 isn't going to weigh that much less than an Allison powered one. The power plant weight of an F4F was 2510lbs not including fuel system.
I'm not really looking for weight, I'm looking for an engine with a better developed supercharger.
Coming up with a superior plane to the opposition is one thing, jumping through hoops and canceling America's Best Army fighter of 1942 just to close up half the performance difference may not really be worth it.
It's 1938 and the war department has told you you have to pick one of their two 1000 horsepower class babies for further development as fighter engines at the expense of dropping the other. This move would force the Army and Navy to settle on either an inline or a radial for planes in that size category. What would you pick?
The P-38? I don't think it ever paid off the tremendous development cost by being productive. Once it got good enough to really start killing planes it was already on par performance-wise with planes that cost half as much.
Saying the proposed radial P-40 would only make up half the difference between the P-40 and the 109 isn't telling the whole story. The radial P-40 would still have its very tough structure, a tougher radial engine (vs. the Allison) and considerable armor without the heavy cooling system. It would still be a boom and zoom fighter, just a much better one.
Further, IMO, it would retain the better flying characteristics of the generally regarded as "easy to fly" P-36. I can't prove the P-36 was easier to fly, but the French, the Finns, and our pilots generally had very positive things to say about its handling. I've also heard the P-40 characterized as "tricky" to fly.
Finally, I think that getting 2 more production lines making a single aircraft would result in more total fighter units being built than the P-40, P-39, and P-38 totals combined.
Why would you think that? I can see the p-38 but why would a factory that could turn out several huderd p-39s a month be able to to turn out more P-40s just because another factory hundreds of miles away was making P-40s?
Once you get the wing loading and gross weight up to the weight of the P-40 (and the weight of the guns out in the wings) what makes you think the radial p-40 is going to handle any different than the inline P-40?
If you want the tough structure you have to take the P-40s weight. the heavy cooling system (all 300lbs of it) pretty much balances out against the the heavier 2 stage supercharger and intercooler of your radial engine. ANd if you go for the R-2000 model it's extra weight will definatly push the powerplant weight higher than the Allison P40 and start heading for the Merlin P-40. It will be a boom and zoom fighter all right, just a dragger one than the inline P-40.
Power loading with R-2000 (1350 HP) @ 8000 lb: .17
Power loading of original P-40: .14.
Draggier? I don't think there would be much difference. The huge mouth radiator of the P-40 made it draggier than most of its contemporaries.
you like adding criticisms but you don't like offering alternatives.What does the power loading have to do with whither a plane is tricky or easy to fly?
ALthough some really high powered planes had trouble with torque.
Power loading of the Hawk 75 with Cyclone engine was .19 at take-off, .16 at 8,200ft and .13 at 19,500ft.
Did the Hawk get tricker to fly the higher it went?
I also think keeping the lines it was originally designed to have over the eventually awkward-looking lines of the P-40.
Got any numbers?
Drag co-effeicients or flat plate equivelent numbers?
You do know that P-36s were 40-50mph slower than P-40s even though the P-36s had 1100-1200hp engines? and were 1000-2000lbs lighter?
Yeah, I can see how that "huge mouth radiator" really slowed the P-40 down
you like adding criticisms but you don't like offering alternatives.
German philosopher Gottfried Leibniz believed that we live in the best of all possible worlds. Do you? You seem to think that nothing sould ever be improved about anything that was done in the allied air war effort.
not attacking, just wondering why you never debate on the positive side of anything. Most people I know with your level of knowledge about a subject feel they know how things could be done better.I see, if the numbers don't back your idea up, attack the critic who points it out.
I just posted a P-36A&C flight manual in the reference section to help this thread along.
See? That's good stuff. A reliable P-38 could change everything. I had no idea that the ETO reliability issues for the P-38 were both fixable and FORSEEABLE. That's amazing. If high altitude escorts could be had for B-17s from day one, if as you suggest they could be armed with 5 cannons, the bombing raids would have hit Germany twice as hard. Fewer bomber crew casualties, more bombers reaching the target.
I have a lot of respect for what concentrated armament can do when deployed in a good fighter. Even with 5-6 50s, it would have a pretty impressive range advantage vs. Luftwaffe interceptors. Nose guns in a pusher or twin engine aircraft can have good accuracy out to 1000 yards versus 200-300 yard ranges for wing guns. Delivering long range escorts in 1943 would change the war dramatically.I am not suggesting 5 cannon. Perhaps 2 20mm and 2 50.s or Three 20s or maybe even four. it depends on how much ammo you want. THe weight of the Hipspano is a bit decieptive because it actualy needed a rather heavy mount in order to be reliable (after all, it was designed to be bolted to an 800-1100lb engine)and with a firing rate about the same as an early .50 it will run through an equel weight of ammo much quicker.
The ETO reliability issues had little to do with the size of the intercoolers. In fact it was partialy the opposit. The Newer P-38s intercoolers worked a little TOO good in cruising flight. THe pilots were being taught in the US to cruise at high RPM and low boost, which was wrong not only for fuel economy but on the P-38 it ment that the turbo was doing very little work and so was heating the intake air very little. After this low heated air went through the intercooler and was partially reheated by the engine supercharger it was still too cold and raw fuel condensed out in the intake manifolds, mixture distribution was poor and other problems. Changing the cruise settings to lower engine RPM but higher boost cured most of the problem with NO mechanical changes. The temperature problem is why it was an ETO thing only. Med and Pacific temperatures were warm enough that the problem didn't occur.
Bigger/better intercoolers earlier means the P-38 could have used higher WER settings earlier
Changing the intercooler space to fuel tanks also increased internal fuel by just over 33%. SO, While the P-38 might not have quite equeled the Mustang, Fighter escort could have been provided over more of Germany months earlier than was done.
If it came down to R-1830 vs V-1710 the powers-that-be would have chosen the V-1710 simply because it gave them a credible liquid cooled engine. They needed to hedge their bets on air-cooled vs liquid cooled in case one or the other proved to be far superior as they developed.
The fact that we still discuss these things now shows that it wasn't a simple or obvious choice.
R1830 displacement = 30L. 567 kg dry.
V1710 displacement = 28L. 633.5 kg dry. This engine requires a liquid cooling system.
I'll go for the R1830. It has a bit more displacement and is significantly lighter.