Engine choices for P-51 mustang ? (1 Viewer)

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The British had a very extensive research and testing programm for all kinds of fuel injection, direct and indirect going back to 1931, and
had even made a solid start on the problem as early Sept 1920. They just threw it all away in March 1937.
That's something I wondered about. Why was fuel injection not developed by the British?
 
That's something I wondered about. Why was fuel injection not developed by the British?
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Its funny you say that its been done people have shoehorned a v8 in a golf. So the sabare thing is possible

Sure, ruining the aerodynamics and probably the range of the -51 in the process.

A fighter plane is a weapons system designed to deliver ammunition onto target. You cannot simply swap out components like Lego blocks without seeing changes elsewhere in performance, for both better and worse.
 
Its funny you say that its been done people have shoehorned a v8 in a golf. So the sabare thing is possible

My post about the VW Golf was very much tongue-in-cheek.

It's only possible to install a larger, heavier engine in an aircraft if you can demonstrate, through correct engineering calculations, that the new weights and balances are suitable, including whether the wing in its current position is sufficient, and whether the existing tail is long enough. You must also demonstrate that the aerodynamics of the aircraft are sufficient to maintain or improve performance.

Changing the engine in an aircraft is a much more complex proposition than it is for a VW Golf. Cars only have one primary vertical force working on it: gravity. An aircraft has 2: gravity and lift (and, yes, lift isn't a vertical force but it always has a vertical component). Get the centre of pressure (centre of lift) wrong on an aircraft and there are no end of problems, and the centre of pressure is entirely dependent on the relative position of the wing and the heaviest airframe weight (typically the engine). Having the centre of pressure too far aft provides insufficient compensation for the weight of the engine, and the aircraft will dive with no means to recover. Putting the centre of pressure too far aft and the aircraft will perpetually stall and or become so unstable that it can't be safely flown. These are problems that you MUST consider in an aircraft but which are irrelevant to a car (VW Golf or otherwise).
 
What about the Packard 5A-2500? Packard was experimenting with an OHC V12 of 161.9mm bore and 165.1mm stroke with a swept volumne of 2540ci (maybe 2489?) and a weight of 650kg in 1938 and early 1939. Rated power was 1500hp at 2500rpm. Max power was 1750 hp at 2800 rpm. Packard had been working on V12s for years with their 4A-2500 V-12 engine passing Army acceptance tests in March of 1928 and producing 950hp @ 2180 rpm @ 6.5 inches HG.
 

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Its funny you say that its been done people have shoehorned a v8 in a golf. So the sabare thing is possible
The VW sits on the ground and doesn't need exact calculations to enable it to operate.

Just making a statement like "oh, I like this engine better, so we should put in here" doesn't take into consideration the physics involved.
The P-51, which had a compact fuselage, was designed for the Allison. It is fortunate that the Merlin was close in size to the Allison, which enabled it to make the transition.

The Sabre was twice as wide as the Allison. So you would have to make the front of the P-51 as big as a P-47 in order to make it fit. Now you have to rebuild the frame to hold the engine and make weight adjustments around the airframe in order for it to safely fly.

So trying to put a Sabre into a P-51 would be more like trying to fit a Viper V-10 into a SMRT car...
 
Take another another look.

That is not a Golf with V-8 engine.
It a a custom chassis (rear drive) with a V-8 engine and Golf body panels draped over the out side.

Using this approach we can simply take a Typhoon, cutaway a lot fuselage panels, weld in some supports and drape some Mustang body panels around it, and just leave any gaps and holes.

The result ought to climb pretty good. It might even turn fairly well at low speed but it will NOT be fast, or do much of anything at high speed.

But is will look like Mustang, if you squint real hard, into the sun, and pretend the holes/gaps are maintenance panels removed for access,
more than few beers will help the illusion ;)
 
What about the Packard 5A-2500? Packard was experimenting with an OHC V12 of 161.9mm bore and 165.1mm stroke with a swept volumne of 2540ci and a weight of 650kg in 1938 and early 1939. Rated power was 1500hp at 2500rpm. Max power was 1750 hp at 2800 rpm. Packard had been working on V12s for years with their 4A-2500 V-12 engine passing Army acceptance tests in March of 1928 and producing 950hp @ 2180 rpm @ 6.5 inches HG.


Hard to say, appears that the 5A was a bit of a mystery with dubious evidence of it ever being produced in anything other than a couple of prototypes.

Going by the 4A, it looks archaic, no better than a Hispano-Suiza 12Y, inlet and outlet ports on the same side of the head. Hopeless.

5A might have been a lot better, who knows, but if it was, odd than it just dissapeared. One suspects upon testing it fell far short of the specs and
was dropped, as is usually the case will all such "vanished engines".
 
The VW sits on the ground and doesn't need exact calculations to enable it to operate.
Not quite correct, just that the calculations for an aeroplane have more serious outcomes than for a car (normally). If you could just slot a V8 into a VW Golf you would have a car that maybe went faster for a short time in a straight line only. The drive train would break, the suspension would bottom out, the weight would be all wrong so it would always want to go straight on in a corner, it would have too little breaking and too much body roll. MAYBE faster in a straight line but certainly slower and less reliable than a Golf GTi. This is why the Golf in S/Rs post had the mods it did, it isnt a "Golf" in any way it just looks like one.

Back in the 70s I had a friend who bought a Honda 750. Instead of trading it in for a newer type he decided to go "the whole hog". He got a Rickman chassis to improve the handling, a big bore kit, special carbs, valves, valve springs, cams and a gas flowed head, it cost him a fortune, but by the time he got it all sorted you could buy a better performing bike (apart from the Rickman chassis) in a showroom. Undeterred he went back to basics, bought a turbo, which meant ditching all the other mods, and getting forged pistons, standard head, cams and valves etc. However by the time he got this all sorted you could buy a Turbo Kawasaki that out performed his in every way, including the Rickman chassis, apart from on a race track. The moral of this story, if you want 2,200 BHP from an engine in 1944 use a Merlin, dont wait for Napier with their Sabre.
 
The Packard V-2500 was resurrected as a marine engine used hundreds if not over a thousand MTBs.

Back in the Packard History they had both inside and outside carburetors on the -3A engines so they could revert back to the inside type when they adapted a single supercharger.
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Now because this was a 1920s engine there were few limitations. Like the 2400-2500rpm limit and the amount of boost that could be used.
It took several years to get the engine up to 1500hp. Many of the early war engines were limited to 1350hp. The Supercharger was used to make power at sea level. If you tried to use the engine in an airplane you would have been down around 20% in power at 10,000ft.
Marine engines were underrated compared to aircraft engines (nobody was really interested in 1 minute or 5 minute ratings in a boat) so they probably could have gotten more out of it. However it used a bigger bore than a Griffon and only 0.10 less stroke and was hundreds of pounds lighter as an aircraft engine so there was going to be limit to how much power you could get get out of it.

Please use caution when looking at the spec sheets for the marine engines. The weight of water cooled exhaust manifolds were included and even more importantly the weight could include the clutch and the gear box. See shift lever in upper photo. The gear box contained both forward and reverse gears and was more than likely a cast iron housing.
 

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