How would the P-38 have performed...

[Connection]

...if they had decided to replace the Alissons with Merlins like they did with the Mustang?

[Pooface]

Originally posted by Connection
...if they had decided to replace the Alissons with Merlins like they did with the Mustang?

well, we shall never really know

imagine a p51 with a gryffon!

why they never did it is beyond me lol

[Glasses]

I don't know but i bet it could deflect bullets like the Merlins in AH do.

[leitwolf]

Originally posted by Connection
...if they had decided to replace the Alissons with Merlins like they did with the Mustang?

The Allisons in the P-38 had turbosuperchargers from the start, the P-40 and P-51 Allison installation was lacking in this department, that's why putting Merlins in place of the Allison brought such a boost. A Merlin in the 38 wouldn't have changed too much... putting a better airscrew on however...

[Kev367th]

Mossie with twin Griffons anyone .

[Debonair]

Griffon powered Mustangs race at Reno every year.
"Precious Metal" is the only one i know by name, but there are others

[Widewing]

Lockheed studied the possible switch to Merlins. Several factors prevented the switch.

Negatives:

First, the Merlin installation would weigh more than the Allisons.

Allisons typically were more fuel efficient than Merlins, meaning reduced range.

There was insufficient production surplus at Packard to support the P-38.

The Chairman of the War Production Board was a General Motors Executive and GM owned Allison. You could expect opposition from the WPB.

Climb rate would not be as good from sea level to Critical Altitude.

Advantages:

Less complex engine installation without turbos and related plumbing.

Improved reliability when used over Northern Europe.


In summary, there was little to be gained and a better solution was switching to high activity props, which the WPB squelched anyway. Too bad, because those propellers demonstrated a 10% to 15% increase in range and a 15% increase in climb rate. Google the XP-38K.

My regards,

Widewing

[Captain Virgil Hilts]

As Widewing stated, they'd have been better of to replace the raggedy bellybutton Curtiss Electric props with Hamilton Standard High Activity Paddle props, first the three blade used on the P-47, and later the four blade version. Never spoke to a pilot from the era who didn't despise a Curtiss Electric prop.

They could also have used the Allison V1710 that was developed for and used in the P-82 twin Mustang, the turbocharging system used with the P-38 engines will work with the twin Mustang engines, which were the best of all the Allison V1710 series.

Just an FYI, no Merlin EVER won Reno until they figured out how to put the rods from an Allison in them.

Had the USAAC bothered to spend enough time and effort to instruct the pilots and crews of the 8th AF on how to fly and maintain the P-38, reliability issues would have been minimized as well. Pilots and planes were lost needlessly, because the pilots simply weren't told about the proper power settings, and how the plane should act.

Oh, and the Merlin was no flawless piece either. More than a few Mustangs were lost when the heads on the Merlins cracked and dumped coolant, or the plugs fouled so badly the engine simply shut down. A P-51 was lost about two years ago over a cracked head or other cooling system failure. I was told by a couple of guys who flew them that once a coolant leak happened on a Merlin P-51, you had a very few minutes to find a place to put it down, or it would sieze rapidly.

[bozon]

Originally posted by Kev367th
Mossie with twin Griffons anyone .

Two for me and a coke please.

Bozon

[Angus]

Ponder on this....
A p38 with 2xGriffons

[Captain Virgil Hilts]

Actually, there's a MUCH easier and more effective swap available. Take two P-82 Mustang V1710 G6R engines and swap them in, hooking them to the original P-38 turbocharger system. Add the FOUR blade Hamilton Standard High Activity paddle props. The engine is a direct bolt in, no modifcations needed, other than swapping the rotation of one engine (easily done in about 3 hours, necessary only if you don't get one of each). The homework on the prop swap was already done by Lockheed on the P-38K. Now, add 150 fuel to allow the boost to run at 80". Now you have a P-38 with nearly 4500HP available under WEP conditions, and with props to use the power efficiently.

The G6R was rated at over 2000HP in many cases, and combined with the turbocharger system on the P-38 could maintain sea level power to over 30K. It was an improved version of the regular V1710 F15/17/30 series equipped with an improved crankshaft and a much better crank driven centrifugal supercharger capable of making in excess of 2000HP WITHOUT the add on turbocharger.

WEP, and possibly even military power, couldn't be used in level flight above 20K, as it would easily propel the P-38 into compression in level flight. However, below 20K it would be a monster, and above 20K, the ability to climb, and maintain speed and energy during combat maneuvers, would be added to the ability to fly in excess of 45K, and a 20% increase in range. There's no doubt, it still wouldn't be the fastest thing up there in levle flight. But the power available to climb and maneuver would give it  extreme advantages in several areas.

As far as the power and reliability of the engines in this configuration, it actually has been tested. The twin Mustang Allison V1710 G6R engines were regularly combined with P-38 style turbocharging systens regularly in the old Unlimited Hydroplanes before the advent of helicopter turbines in the boats. There was at one time a good sized supply of the twin Mustang engines in surplus, and you could pick them up for a song. However, the hydroplane and tractor pulling guys used them up.

[Squire]

For operations in the ETO I think they would have preffered the Merlins in the early P-38s had they been able to make the switch. For the Pacific, where it was warmer, and the Allisons didnt have to deal with the very cold temps, and they tended to fly lower anyways, it would have made little difference. Since the P-38s had the seperate superturbochargers installed their performance at alt was always pretty good, unlike the Allisons in the single engined fighters, like P-40 and P-39.

Allison to Merlin switch would have made the most difference in the P-51, and the least in the P-38. Which is maybe why thats exactly what happened.  

Since the P-40s and P-39s were already earmarked by the USAAF to be replaced during the war by the P-38 and P-47, modifying them would have been a waste of time and resources.

When the decision was made to convert the 8th AF FGs to P-51s in 1944, I think that quashed any serious discussion about improving the P-38 further than the J/L series, as they could see the war in its final year anyways. Its a cost-benefit call. Lots of a/c that would have been improvements never saw the light of day (on all sides) because the requirement wasn't there.

[Captain Virgil Hilts]

Actually, the G6 series Allison was available long before 1944. And the improvements would have made a great deal of difference to the P-39, the P-40, and the P-51. Of course, it would have made a big difference for the P-39 had the USAAC not removed the turbocharger.

The P-38K prototype also flew long before 1944. Actually 1943 is more like it.

Once you get above 20K, the temperature does not vary nearly so much as you might think from region to region.

The Merlin equipped P-51 had at least as severe a set of teething issues as the P-38 did. The high altitude issues with the P-38 were mostly related to maintenance and procedures, although the design did exacerbate those problems.

[Angus]

Once asked an old pilot if it wasn't cold at those alts like 30 or 40 K.
He said exactly what you did, that after 20 it didn't really matter so much.
He added that the air in the med up at 20K was colder than over N-Europe.
And, over 40K you can see the sky getting slowly darker...deeper blue.

[Squire]

Well, even by 1943 the USAAF was rapidly converting from the P-40 and P-39 to the P-38 and P-47, so I don't see why they would bother to upgrade them, only to retire them within months. Im not saying they couldn't have done upgrades, and im sure they considered that as an option, but in the end I think the right choice was made to move on to better types. The USA could produce large #s of a/c quickly, and so it makes sense based on its capacity for production.

The USN went the same way, going to the F4U and F6F and replacing the F4F rather than just improve it, although the FM-2 did see service in a niche role into 1945.

There were a lot of a/c that could have been upgraded, but design technology rose dramatically during the war, and newer types came out at a very fast pace.

In regards to the P-38, it was *the* premier USAAF fighter in 1942-43, and the demand for it in the ETO, MED and PAC outstripped Lockheeds ability to keep up to the orders, and any delay of it would have been quashed, my understanding is the fear of a production delay in the P-38K (perhaps in error, in retrospect), killed that program. To convert the P-38s over to the Merlin, even if they wanted to, would have in all likelyhood been cancelled if they felt production would have been slowed.