What was the problem with the allison engine?

[EKB]

You started with a diatribe against the engine but now your saying - "I think this reinforces my earlier post showing that the P-51B was a highly defective airplane in the spring of 1944."

I posted the following message three days ago about defects found in the P-51B, many of which were not engine-related, so I have no idea why you now contend that point wasn't raised earlier:

You need to show us when Mustangs with the Allison engine suffered this many problems:


" Operational Diary—1944 [4th Fighter Group]

25 February 1944—The ground crews had their hands full trying to get about 50 Mustangs [P-51B] ready for combat. Before morning all of the kites had been painted in QP, WB, VF livery in anticipation of the first Mustang show the next day.

26 February 1944—Weather scrubbed the 4th's Mustang debut but at least there was time for familiarization …

27 February 1944—At 1315 a Rolls-Royce tech representative held a briefing on the P-51. Don Blakeslee held a discussion on flying problems with the Mustang which had been disappointingly numerous. A plague of mechanical gremlins diminished the pilots' enthusiasm for the new fighter. Jim Goodson, Willard Millikan and George Carpenter had bounced the new paddle-bladed P-47s of the 56th and frustratedly reported that these Thunderbolts were a match for the Mustang upstairs and downstairs. This added to the air of uncertainty.

28 February 1944—Maj. Clark led the first Mustang mission, a Free Lance under Type 6 control with two 75-gallon drop tanks under the wings of each kite … Both 334 and 336 got 12 aircraft up while 335 put up 11, but there were several aborts due to mechanical problems …

29 February 1944—The P-51's ugly side reared its head—Mills prop began throwing oil and his wing tanks would not feed; Biel's cooling system and RT went out Beil's cooling system and R/T went out; Rafalovich could not get enough manifold pressure and his R/T also quit. France, Chatterley and Smith could not catch up with the Group. All six were forced to abort the mission. After everyone got back a bunch of disgruntled pilots went to the briefing room at 1645 to hear a 354th Group pilot talk about mechanical failures with the Merlin engine.

4 March 1944—During combat several pilots were hampered by windscreen frost and jammed guns. At 18,000 feet and 550 mph indicated, Ward's canopy, wing and tail came off, hitting Megura's kite … Paul Ellington had engine problems and bailed out over the Dutch Coast … Bob Richards was killed when he went in near Framlingham returning from the show. Blakeslee returned fuming, his guns wouldn't fire at all.

[John Godfrey later said that Richards crashed due to motor trouble].

7 March 1944—New spark plugs were put in the kites to see if this might improve the engine problems.

8 March 1944—In spite of claims of 16 destroyed, rough engines and unservicable drop tanks were the order of the day.

13-15 March 1944—In spite of the successes against the Germans, the P-51s were mechanical nightmares and they were grounded. Rough engines, props throwing oil, glycol leaks and auxiliary tank feed problems were causing aborts on every mission. These two days all the wing bolts were replaced and engine mount bolts were magnafluxed, but these precautions weren't effective. On the 17th Burtonwood manufactured new motor mount bolts but even these turned out to be unsatisfactory and by April North American had to rush 250 sets VIII FC.
Table II prop kits for the Mustang arrived in February and March stripped and useless, so propellers continued to be in short supply until July. V-1650 engines were also in short supply through March and April. All this added up to low mission strengths for quite a while. Many times a squadron was able to get but 10 airplanes up for a mission. To get 20 up was a minor miracle …
The gloom over losses due to engine problems was hard to dispel. At least five pilots went down during March due to glycol and engine failures, possibly more since several losses are noted due to unknown causes. The gunnery and electrical systems also failed with regularity, resulting in lost kills. And the installation of the 65-gallon upright tank behind the pilots' seat without baffle plates to prevent violent shifts in the center of gravity was considered a nightmare by several pilots.
Blakeslee's crew chief, Harry East Jr. never could get the right bank of the Chief Cook's Merlin to quit smoking and missing. Col. Don kept the kite because it was fitted with a better-vision Malcolm hood. 43-6437 was not replaced until the hydraulic line was perforated, much to East's relief.".


See p.40-45
Garry Fry Ethell. Escort To Berlin: The 4th Fighter Group in World II. Arco, 1980.

I'm pretty sure that the pilots who turned back early from a mission did not feign those kind of problems because they had a hot date in London.

what people say and think now has no bearing on 70 years ago.

If only you practiced what you preach.

 

[fastmongrel]

I cannot understand the thread of your argument you seem to have two opposing views. I am out of this discussion now as you seem to be heading towards being personal.

As the great Jedi Master Yoda said recently. Fun you will have on your own

 

[FLYBOYJ]

I think this reinforces my earlier post showing that the P-51B was a highly defective airplane in the spring of 1944.

I show 1,578 Allison Powered Mustangs built, 1,987 P-51Bs and 1,750 P-51Cs (Texas razorbacks) built. I believe some of the Allison P-51 production run overlapped P-51B/C production. Although you keep showing individual combat reports, if the P-51B was truly "defective" as you say, don't you think someone at the war department would have stopped Merlin production and reverted back to an all Allison fleet or just cancelled the P-51 Merlin production line all together?

What you're showing IMO was no different than many of the other aircraft entering combat service, especially in the numbers, environment and mission assignments this "new" airframe was expected to perform in, if anything the P-51B performed well despite the examples you're showing. Agree, there were some major issues with the P-51B when it first entered service and there was much improvement needed to get the full potential out of the aircraft, but despite these issues I think history tells us that the marked improvement over the Allison airframe was apparent. I've met several WW2 veterans who flew both versions and even spoke of some of the same issues you're trying to highlight, but in the end they would have chosen a Merlin powered P-51, except for Col. Mike Alba - he would have preferred to stay in the P-38!!!

 

[pbehn]

A defective airplane is defective, not just in the first few weeks it appeared. Things like oil and coolant leaks are production quality control issues not the aircraft design and complaints about the radio have nothing to do with the aircraft. To suggest that the merlin itself was defective in 1944 is a little off the wall, it powered almost all British front line fighter recon. and bomber aircraft up to that time, especially the ones on the longest missions with two or four of them.

 

[FLYBOYJ]

Things like oil and coolant leaks are production quality control issues not the aircraft design and complaints about the radio have nothing to do with the aircraft.

Many of these aircraft were test flown at the factory, disassembled and then shipped to Europe, reassembled and sent off to squadron so the potential for "quality" issues were great.

 

[pbehn]

Many of these aircraft were test flown at the factory, disassembled and then shipped to Europe, reassembled and sent off to squadron so the potential for "quality" issues were great.

I was going to make a similar point but I dont know how far they were disassembled after their test flight at the factory. Most of the problems highlighted should have been sorted in commissioning checks. I would think that is what was done to solve them, all part of learning how to put a new piece of kit in service.

 

[tomo pauk]

...To suggest that the merlin itself was defective in 1944 is a little off the wall, it powered almost all British front line fighter recon. and bomber aircraft up to that time, especially the ones on the longest missions with two or four of them.

Or just with one of them

 

[gjs238]

I wonder if the V-1650 powered P-40's also had such development issues.

 

[GregP]

The P-40F did not have a lot of issues but, being a single-stage engine, was also not better than the Allison P-40. Some were a few mph faster. Some weren't. As far as I've been able to check, the two airplanes were about equal in performance with the Merlin version deleting the carburetor airscoop, making for marginally better visibility.

Either engine seems to have been about the same. Now had they put in a 2-stage Merlin, then we'd have seen a real jump in P-40 performance. The single-stage planes weren't much given to playing at ETO combat altitudes.

 

[GrauGeist]

I wouldn't spend too much time arguing with this person, as this exact same argument happened here: Reliability of aircraft engines nearly 10 years ago.

With virtually the same figures pulled out of context to support the same circular argument

I will say that perhaps the single most informative comment in all 9 pages of that particular discussion, was in another member's reply:

"Anecdotal information is difficult to include and draw reliable conclusions from"

 

[tomo pauk]

I wonder if the V-1650 powered P-40's also had such development issues.

Nope.

 

[pbehn]

Or just with one of them

Well, I considered including single engined aircraft but then someone would have said they were mainly point interceptors, only a small percentage of Spitfires were long distance recon versions, but by 1944 they had been venturing into Germany with Merlins for a long time.

 

[tomo pauk]

The Fulmar was also managing long missions, combat included, over the water for the start. On a single Merlin engine.

 

[pbehn]

The Fulmar was also managing long missions, combat included, over the water for the start. On a single Merlin engine.

Yes, that is the sort of comment for no reason whatsoever that I was trying to avoid, valid though your comment is it is it is a distraction, the merlin was originally designed for single engined aircraft, if it had been consistently unreliable it would not have been chosen to power four engined bombers for long distance bombing raids. I am not saying it was better than the Allison in reliability, I am saying it was not an intrinsically unreliable engine in 1944, whatever airframe it was bolted into.

 

[pbehn]

Nope.

Were the ground crews used to dealing with water cooled engines? Were P51B ground crews used to dealing with water cooled engines? This is how a discussion goes off on a wild tangent.

 

[GregP]

This isn't much of a discussion anymore. It started off asking about the Allison and morphed into a discussion of the Merlin. Go figure.

On topic, there was nothing wrong with the Allison that a change in USAAF requirements would not have cured. The choice of high-altitude boost systems was the USAAC's choice, a turbocharger. Had they hedged and asked for multiple high-altitude boost systems, we might have had a different story. But we didn't.

There is nothing wrong with the Merlin as a service engine. It takes a lot of labor to overhaul it, but in service it runs just fine.

And it doesn't matter a bit what an aero engine was designed for. It matters how it gets used and what the results are. The reputation, good or bad, is earned in the air, not in the design phase. Merlins did everything asked of them and more. Allisons did, too.

If the turbo installation was debugged, it worked fine, If it was an early system, it had a few issues that were addressed and solved; a bit later than the Merlins, but they were solved. A P-38J or L had no real turbo issues other than normal in-service things that happen. They never did let Curtiss put a turbo in the P-40 or Bell complete the turbo in the P-39, so those were low-altitude airplanes.

The engines weren't bad, they performed as advertised at the altitudes expected, and made overhaul as expected. It's just that the enemy wasn't fighting where the P-39s and P-40s were flying all that much.

 

[DerAdlerIstGelandet]

I see EKB is trying to ruffle feathers again...

 

[GregP]

Hey EKB,

You better stop while you're still in good standing. Mission abort rates are not necessarily attributable to the aircraft. If the main abort reasons are systems, then the aircraft is to blame. If the main abort reasons are engines, then the engine is to blame. Also, the abort rates for each engine are a great subject to explore.

Look really hard at bombers. They have multiple engines and can generate very realistic engine failure rates quickly.

Single-engine fighters can do so with some camouflage. Did a Curtiss Electric prop fail due to motor brushes? Or what? Was it a burst oil line? What about an electrical fault?

You have shown abort rates for some P-51s. What about the same data for P-47s or P-39s or P-40's or Spitfires or Hurricanes, etc.?

Use the scientific method and form a hypothesis and attempt to disprove it yourself. If you can, it's wrong. If you can't it MAY be right.

Good luck.

 

[GrauGeist]

Greg, don't forget even a hard landing can knock prestone lines loose or foul other equipment which in turn can cause trouble on the next "go-round" unless the crew spots it before hand.

 

[GregP]

Not forgetting ... I can't elaborate every possibility in a short post, but I get your point.

Mission aborts are generally attributable to some system, be it powerplant, prop, gear, hydraulic, gasoline (as in run out), electrical, or some system failure. It certainly isn't combat if it is an abort.

Could be armament arming issues as well as anything else. If you can't shoot, you'd better RUN.

Some analysis might be indicated.