Aircraft Quirks

Sgt. Pappy · 06-20-2006, 05:39 PM

OO I see.. but wait... wmaxt, when you said that 'the problems were fixed' does that mean engine failures at high altitude were not as common anymore - about as common as the P-51's engines aborts?

But these spark plug foulings... about how common were they? My sources seem to show that the spark plugs SOLVED the actual problem of hihg-alt. engine failure.

Jank · 06-20-2006, 07:16 PM

Related subject from my post on another thread:
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Remember when Yamamoto was killed? That particular mission, flown by the 339th, was labeled "SQUADRON 339 P-38 MUST AT ALL COSTS REACH AND DESTROY. PRESIDENT ATTACHES EXTREME IMPORTANCE TO MISSION." The planes were in tip top condition to be able to carry out this critically important mission. Even so, they had more than 10% of their flight turn back due to "engine problems."

Until the J model the problems were pretty bad.

http://home.att.net/~ww2aviation/P-38.html
Many of the P-38's assigned to escort missions were forced to abort and return to base. Most of the aborts were related to engines coming apart in flight. The intercoolers that chilled the fuel/air mixture too much. Radiators that could lower engine temps below normal operating minimums. Oil coolers that could congeal the oil to sludge. These problems could have been fixed at the squadron level. Yet, they were not. It took the P-38J-25-LO and L model to eliminate these headaches.

http://bob.hentges.lu/articles/en/p38.html
The Allison engines of the Lightnings proved to be somewhat temperamental, with engine failures actually causing more problems than enemy action. It is estimated that every Lightning in England changed its engines at least once.

The powerplant problems were not entirely the Allison engine's fault. Many of the reliability problems were actually due to the inadequate cooling system, in particular the cumbersome plumbing of the turbosupercharger intercooler ducting which directed air all way from the supercharger out to the wingtips and back. In addition, the lack of cowl flaps were a problem. In the European theatre of operation, temperatures at altitude were often less than 40 degrees below zero and the Lightning's engines would never get warmed up enough for the oil to be able to flow adequately. Octane and lead would separate out of the fuel at these low temperatures, causing the Allisons to eat valves with regularity, to backfire through the intercooler ducts, and to throw rods, sometimes causing the engine to catch fire.

These problems bedeviled the Lightnings until the advent of the J version with its simplified intercooler ducting and the relocation of the oil cooler to a chin position underneath the propeller spinner. When the P-38J reached the field, the Allison engine was finally able to attain its full rated power at altitude, and the engine failure rate began to go down.

Sgt. Pappy · 06-20-2006, 08:19 PM

Wow you people are awesome... any tips for searching for information like you guys do? I don't want to keep aggrivating you lol. But, once again, thanks.

FLYBOYJ · 06-20-2006, 09:56 PM

Great info Jank, but a note, most of the problems noted were mainly encountered in the ETO. Early G's and H's had their problems but for the most part their FMC rates were good in the PTO...

Twitch · 06-21-2006, 10:45 AM

Aborts were an accepted occurance simply due to the fact that airplanes of the time were very complicated entities. They still are. DOn't read too much into it. Guys turned back for a huge variety of reasons real or perceived. At times a "rough running" engine at the cruise speed of the squadron could cause and "I'm turning back." Pilots were attuned to their machines and literally could feel subtle vibrations and sense other problems by the way the crate reacted.

Today fighters would mostly not abort once in flight but would not be deemed flightworthy by the crew chief and allowed to take off at all. The diagnostics has improved to the point where that happens instead of in-mission turn backs. Lot safer all around if problems are found and the aircraft is scratched from flight status ie., you don't risk losing the plane or pilot.

FLYBOYJ · 06-21-2006, 10:52 AM

I think a major source of these problems were improper leaning by the pilots. If you run an aircraft engine too rich, you will foul the plugs, to lean and you'll burn valves. In many -1s it was SOP to put the mixture control at full rich when you went into combat, this was done for cooling. I believe that many times the mixture controls weren't adjusted after combat which created other problems.

I know that many fighters had an auto mixture feature but I believe that many pilots still went with their own mixture settings for various reasons...

Jank · 06-21-2006, 12:50 PM

Twitch said, "Aborts were an accepted occurance simply due to the fact that airplanes of the time were very complicated entities."

Indeed. The occurrence rate however, appears to have been far higher in the P-38 than with any of the Stang or Thunderbolt models. Hence the problem. If the occurrence rate was on average with other aircraft used in the P-38's role, it would not have been an issue.

Flyboy said, "I think a major source of these problems were improper leaning by the pilots.

Doesn't sound like "pilot error" to me. Sounds like there were genuine mechanical issues.

FLYBOYJ · 06-21-2006, 01:00 PM

Quote:

Originally Posted by Jank

Doesn't sound like "pilot error" to me. Sounds like there were genuine mechanical issues.

NOPE!! The pilot leans out the engine and changes the airfuel mixture based on density altitude and operation. This is purely an operator function and controlled by the pilot and the pilot only!! unless the aircraft is equipped with autolean which will take about 50% of the process away from the pilot.

Marshall_Stack · 06-21-2006, 01:14 PM

I don't know if this is considered a "quirk", but the wildcat didn't have hydraulic retraction of the landing gear. It was done manually with the pilot having to crank a handle 29 times until it came up. As the plane was going into its climb after takeoff, the plane could be seen going on an erratic path as the pilot was trying to crank up the gear and fly at the same time.

FLYBOYJ · 06-21-2006, 01:28 PM

Quote:

Originally Posted by Marshall_Stack

I don't know if this is considered a "quirk", but the wildcat didn't have hydraulic retraction of the landing gear. It was done manually with the pilot having to crank a handle 29 times until it came up. As the plane was going into its climb after takeoff, the plane could be seen going on an erratic path as the pilot was trying to crank up the gear and fly at the same time.

True - Wildcat pilots I met said that they learned to master turning the crank and flying at the same time.

evangilder · 06-21-2006, 03:33 PM

Yep, the same mechanism as the F3F. Taking off in a working machine isn't so bad. Could you imaggine being shot up and possibly injured, then having to hand crank the gear down?

Gnomey · 06-21-2006, 06:11 PM

Pretty sure it was the same in the early Hurricanes and Spitfires too. It would be hell having to pump down the landing gear if you/the plane/both were damaged.

Nonskimmer · 06-21-2006, 06:25 PM

Quote:

Originally Posted by Gnomey

Pretty sure it was the same in the early Hurricanes and Spitfires too. It would be hell having to pump down the landing gear if you/the plane/both were damaged.

The Spitfire Mk.I had the hand operated pump for the landing gear, but I think only the Hurricane prototypes did. As far as I know, the production models all featured an engine driven pump.

Sgt. Pappy · 06-21-2006, 06:27 PM

Also, cranking the gear obviously became a tiresome task and pilots would sometimes let go in the cranking process. This could cause them some wrist injury as well. Imagine that... before you even go into combat your hands are already broken.

pbfoot · 06-21-2006, 06:33 PM

To drop the gear on the wildcat it was not unknown for the pilot to unlock the gear and yank up on the stick saving the the task of hand cranking