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XyZspineZyX
09-12-2003, 08:12 AM
Hi!

Yesterday I came to think of development of US aero-engines. The US kept on developing a long pedigree of succsessfull radial engines all through the thirties and the fourties. But when it comes to V-engines, it seems like it all stopped before WWII.

The P-38, P-39, P-40 and P-51 all had Allison V1710 in some form or another. Eventually at least the P-40 and P-51 had Rolls Royce Merlins or its Packard-built equivalent, the V1650. The P-38 would probably had come out a lot better with the V1650 too, but it retained the V1710 through its carreer.

The brits refined the Merlin to extreme outputs, then they had the Griffon, the H-configured Napier Sabre, etc.
The germans made the DB600-series vastly more powerfull. All of this development came during the war. At the same time both countries developed the jet-engine. The US had to get blue-prints of jet-engines from the british.

Am I wrong, or didn't the americans develop any better watercooled engine than the Allison V1710?

Skarphol



Message Edited on 09/12/0310:00AM by Skarphol

XyZspineZyX
09-12-2003, 08:12 AM
Hi!

Yesterday I came to think of development of US aero-engines. The US kept on developing a long pedigree of succsessfull radial engines all through the thirties and the fourties. But when it comes to V-engines, it seems like it all stopped before WWII.

The P-38, P-39, P-40 and P-51 all had Allison V1710 in some form or another. Eventually at least the P-40 and P-51 had Rolls Royce Merlins or its Packard-built equivalent, the V1650. The P-38 would probably had come out a lot better with the V1650 too, but it retained the V1710 through its carreer.

The brits refined the Merlin to extreme outputs, then they had the Griffon, the H-configured Napier Sabre, etc.
The germans made the DB600-series vastly more powerfull. All of this development came during the war. At the same time both countries developed the jet-engine. The US had to get blue-prints of jet-engines from the british.

Am I wrong, or didn't the americans develop any better watercooled engine than the Allison V1710?

Skarphol



Message Edited on 09/12/0310:00AM by Skarphol

XyZspineZyX
09-12-2003, 09:43 AM
Well the Allison's were not bad at all. Easy to maintain, simple, and cheap. The late war Allison's on P-38's produced 1650HP each. Not bad at all. Also, the Merlin's did not have a version that would be suitable for the P-38 and its counter rotatin. All said, yes there was better aircraft engines, but the Allison's did well.

Gib

Skarphol wrote:
- Hi!
-
- Yesterday I came to think of development of US
- aero-engines. The US kept on developing a long
- pedigree of succsessfull radial engines all through
- the thirties and the fourties. But when it comes to
- V-engines, it seems like it all stopped before WWII.
-
-
-
- The P-38, P-39, P-40 and P-51 all had Allison V1710
- in som form or another. Eventually at least the P-40
- and P-51 had Rolls Royce Merlins or its
- Packard-built equivalent, the V1650. The P-38 would
- probably had come out a lot better with the V1650
- too, but it retained the V1710 through its carreer.
-
- The brits refined the Merlin to extreme outputs,
- then they had the Griffon, the H-configured Napier
- Sabre, etc.
- The germans made the DB600-series vastly more
- powerfull. All of this development came during the
- war. At the same time both countries developed the
- jet-engine. The US had to get blue-prints of
- jet-engines from the british.
-
- Am I wrong, or didn't the americans develop any
- bether watercooled engine than the Allison V1710?
-
- Skarphol
-
-



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XyZspineZyX
09-12-2003, 11:00 AM
putting merlins in the 38 would have been a mistake if you ask me.

the allisons were turbo super charged. the L model retained sea level hp up to 28,700ft the 1650-7 made 1,720hp but only to 6,250 ft and it lost hp till it was down to 900 hp at 30,000ft.

the allisons were more fuel efficiant than the 1650.

once the bugs were worked out in the 1710s in the ater model 38js through L models, they were more reliable than the 1650 in the mustang.

the 1710 F-30 in the 38L was cleared for 1,725 hp by allison. the army air corps never authorized use of this rating, but none the less it was able to be run at higher hp than the 1710 F-17s in the 38H/J

the allison installation in the 38 was lighter by a few hundred pounds when compairing it to a merlin installation in a 38.

XyZspineZyX
09-12-2003, 11:31 AM
A quite informative article on Merlin installation in the P-38 is http://home.att.net/~C.C.Jordan/P-38K.html ,even though I have noe idea of how reliable this source is, as he seems very 'pro-merlin'.

But to me the V1710 seems like a quite 'old-fashion' design, or was it simply ahead of its time when it was developed? Why did the P-51 end up with a Merlin if it wasn't better? Because of high-altitude missions? And why didn't it have a Griffon when these came?

Im absolutely not an expert on engines, and are not pro-british engines, I just find it weird that an innovative country like the US stuck to the V1710 all through the war. Espescially when one look at their enormous development in radial engines in the same periode.

Skarphol

XyZspineZyX
09-12-2003, 11:49 AM
There was an attempt to put Merlins in the P-38. With some lobbying in Washington, GM stopped the attemp. GM was Allison's parent company.

Inline engine development did not end in the US. Continental, Lycoming, Crysler all tried to make engines but for numerous reasons they did not go into production.

P&W had the X-1800 and X-3730 engines. When the R-4360 finally should promise in the early '40s they were dropped. The designer was also very sick at the time, even working from bed at home.

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"Only a dead 'chamber pot' is a good 'chamber pot'!"

XyZspineZyX
09-12-2003, 09:03 PM
MiloMorai wrote:
- There was an attempt to put Merlins in the P-38.
- With some lobbying in Washington, GM stopped the
- attemp.

Do you have more information on this?

XyZspineZyX
09-12-2003, 11:05 PM
There was nothing wrong with the V-1710. It biggest drawback was the lack of an integral auxillery supercharger. It lacked it because it was designed to have used a turbosupercharger.

The V-1710 was a very robust engine. In American use, it went longer between scheduled overhauls than did the Packard Merlin. It could withstand very high manifold pressures, up to and over 100" hg.

The developement of the hydraulic auxillery stage supercharger as used in the P-63 meant that it could be a viable high altitude engine.

The P-82 Twin Mustang used the Allison engine. It was a fantastic performer.

The best performing experimental P-51, the XP-51J, used a V-1710 engine. Top speed was to be 490 hp with a climb rate in excess of 6,000 fpm.

V-1710s with experimental compound supercharging (turbo, super, and engine stage) produced 3000 hp.

V-1710s are used to this day in power boat and racing plane applications. Merlin engine still in use generally use some Allison parts.


Don't write off the Allison, it was a great engine.


Regards,

SkyChimp

http://members.cox.net/rowlandparks/NAA_logo.jpg

XyZspineZyX
09-13-2003, 12:45 AM
yes I agree too that the 1710 was a stronger more modern design than was the 1650-7

lack of a second stage super charger was the problem with the 1710. The P-38's second stage super charger was the turbo which was a better 2nd stage super charger than the 1650-7s mechanical unit

The F-30s in the 38L made more hp above 6,250 ft than did the 1650-7 of the 51D, if you ran the F-30s at their allison rating, they developed more hp at all altitudes.
even at the army air corps rating, at 30,000ft the F-30s in the P-38 made 2 times the hp than did the 51D's 1650-7

P-51J had a 1710-119 F-32R which made 1,900 hp and as skychimp pointed out, it was the fastest mustang.

P-82E ran 1710-143/145s that made 2,250 hp

the whole engine design of the allison is more modern than the 1650, look at a picture of the two and see what you think.

remember the P-38 was the only a/c to have reliability problems with allisons. P-39,40, and 51s that ran allisons were reliable.

the problems in the P-38 can be traced to these issues,

1 coincident with the introduction of the P-38Js was the arrival in england of many new and inexperienced pilots

2 engines were routinely being operated at the new 1,600 bhp WER rating that was obviously closer to the detonation limits than the earlier restriction of 1,425 hp in the 38H

3 at 1,600 bhp the engine maintenance requierments were exacting. exhaust plugs were to have been changed after every flight that WER was pulled. this was not always done, leading to lead fouling and increased likelihood of detonation during subsequent operations at WER. many mechanics were not familiar with the allison 1710s. many had been trained on the R-2800 further leading to engine reliability issues

4 pilots were arriving from the us were they had been trained to use high rpm and low map when cruising on combat missions. this was very hard on the engines and not consistent with either lockheed or allison technical instructions.

5 fuel being provided in england for the P-38 during the winter of 1943/44 was not entirely adequate, as the TEL would condense in the manifolds, particularly during cruise, and lead to destructive detonation.

6 the improved intercoolers were providing considerably lower manifold temperatures, which allowed TEL condensation during cruise, as well as increasing the likelihood of plug fouling.

once these issues were addressed and late J model and L model 38s the allison became more reliable than did the 1650-7.

flying hours and labor to overhaul 1710s and 1650s

1945 1st quarter

1650 302 flying hrs 251 labor hours to over haul engine
1710 362 flying hrs 134 labor hours to over haul engine

1945 2nd quarter

1650 200 flying hrs 259 labor hours to over haul engine
1710 387 flying hrs 153 labor hours to over haul engine

did you know that the 1650s that are run in the unlimited racers at reno use allison 1710 connecting rods because they are stronger than the original 1650 rods.

pick up the book "Vee's for Victory" by Daniel D. Whitney isbn 0764305611 by schiffer publishing

XyZspineZyX
09-13-2003, 01:23 AM
Skarphol
Sorry no, just the basic story.

--------

An Allison with twin turbos powered an Unlimited Hydro to a win this year beating the T-55 powered boats.

http://a1276.g.akamai.net/7/1276/734/625ed428e022ef/www.harley-davidson.com/PR/MOT/2004/Softail/images/DOM/img_Softail_FXST.jpg

http://www.redneckengineering.com/photogallery/photo23581/curves-done-03.jpg


"Only a dead 'chamber pot' is a good 'chamber pot'!"

XyZspineZyX
09-13-2003, 02:03 AM
The turbosupercharger was the 1st stage, not 2nd. The 1st stage is the first compressor the air goes through. The second stage is the second, and so forth.

On the P-38, the turbo was the 1st stage, and the engine stage supercharger was the 2nd. On the P-63, the hydraulic supercharger (or auxillery supercharger) was the 1st stage and the engine stage supercharger was the 2nd.

Regards,

SkyChimp

http://members.cox.net/rowlandparks/NAA_logo.jpg

XyZspineZyX
09-13-2003, 02:17 AM
For refference, hydro racing destroyes aero engines extremely quickly. One of the main reasons an engine core now costs $25,000, rather than $250, is because the boat and tractor people have totalled so many of them.

The only other way to destroy a core is by overboosting the engine, and considering how some of these engines can take over 150 inches of boost, that's pretty hard unless you're racing.

Harry Voyager

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Message Edited on 09/12/0308:20PM by HarryVoyager