P-38 limited to 420mph

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taly01

Senior Airman
356
290
Sep 5, 2016
Australia
I read that the P-38 had a recommended dive limit of 420mph, then if you see that even the last P38-J only had a speed of 414 mph.

Was there some airframe 'compressibility' problem that prevented the P-38L going 420mph even with 3,200hp WEP! It certainly looks bad against the last P-47N and P-51H that are up around 460-490mph. maybe thats why you never see P-38 in air racing.
 

The dive limit speed of 420mph is an indicated air speed, which means that at altitude the true air speed is quite a bit higher.

At the P-38's critical altitude (~26,500ft) 420mph IAS is approximately 620mph TAS.

The top speed listed is true air speed. At critical altitude the maximum speed is around 275mph IAS.

*My numbers may be slightly off, as I used a calculator on the web.
 
The main reason you don't see P-38s at Reno is because they run 2 engines and there just weren't and aren't very many around. Gary Levitz and Lefty Gardner both used to race P-38s in the stock class and they always put on a good show. Being a bit rare, they tended to stay in more or less stock shape, mostly because they would require a lot of tweaking for racing.

Today we have 7 ariworthy P-38s in the world. Two are based at Chino, CA.

Here is a shot of Lefty at the typical altitude he used to fly at Reno, going past a back-of-the-course pylon. On the next lap Gary was trying to pass and Lefty came around with his wingtip passing through a bush near the same pylon. Joe Yancey has a great shot of that event, with the wingtip going through the bush! When he landed, there was a small stick stuck in the wingtip. When the FAA guy came over and asked him, "What happened?," Lefty replied, "I hit a bird!" The FAA guys said back to him, "Was he still in the nest?" He wasn't smiling.

They made a rule that the minimum altitude was the top of the pylon after that. Any lower was a DQ. Lefty's plane is a P-38L (N25Y) but he ran F-model cowlings because the only time he throttled up the engines was at Reno, and it was only for the race laps, and the F-model cowlings were faster on the same power than the L-models cowlings ... but they couldn't support more than about 1,100 HP per engine without the temps rising.

Lefty always stayed cool approaching the race and slowly heated up as the race went on, and he was usually right at or just over the top of the green when the race ended. For this picture and race, Pat Yancey washed the plane with 409 cleaner and it actually looked white where the exhaust didn't discolor it. You can see the fins are starting to get re-stained in this pic.



Lefty was a neat guy to talk with and we all miss him. This plane is now in Austria as the Red Bull plane.
 
I was told the Bill Klaers Westpac resto was number 7. Let's count.

1. There's the Red Bull unit in Austria (Left Gardner's old plane). P-38L.

2. There's the Planes of Fame P-38J 23 Skidoo. This plane will fly (weather permitting) at the Planes of Fame on the 1st Saturday in February as our monthly event feature. Come see it fly if you're anywhere near. Usually flies about 11:30 - noon, depending on how long the presenters speak.

3. There's the former Honey Bunny, now unnamed after Jeff Harris passed away (Honey Bunny was his girlfriend) of Allied Fighters at Chino. P-38L.

4. There's Rod Lewis' P38F Glacier Girl.

5. There's Tangerine in Oregon. P-38L. Tillamook has a great museum, and they DID have 2 until Jeff Ethell passed away in one of them.

6. There's Fagen's P-38L in Granite Falls, MN (I call it Frostbite Falls, from Rocky and Bullwinkle). P-38L.

7. There's Thoughts of Midnight from Texas. P-38L.

The P-38L at Yanks in Chino is listed as airworthy on the web … but it DOES NOT FLY; NEVER. Not airworthy. It would take a year or more to get it airborne. I'd bet more. Doesn't count unless it flies occasionally. Don't believe the "airworthy" crap ... but we DO have 3 P-38s at Chino. Heck, the carburetors haven't been removed in 10+ years, and we all know Allison carbs require rebuilding every 5 years, if for nothing else but seals. The props also haven't been removed in that time. Anybody care to guess how well a Curtiss Electric prop works when the brushes haven't moved in 15+ years? Most people have issues if they don't fly one for even 1 year.

So, I believe the Westpac unit (8.) takes it to 8, and it looks like I miscounted and spoke too soon there.

Did I miss any?

I believe Joe Yancey Allisons hum in all of them (the airworthy ones ...) except the Red Bull unit that runs Allisons from Bud Wheeler. It doesn't fly very often, but it DOES commit aviation on occasion, usually over the airfield.

I know some are in restoration. But predicting a first flight is about like a 1st-time golf player getting a hole in 1. I know maybe 20 people who have buit an airplane. None of them has come anywhere CLOSE to their 1st-flight prediction. Hence the phrase, "The last 5% takes 50% of the time to complete!"

Here's a clip from our 2013 airshow, We had five P-38s there flying, plus the "flyable" one from Yanks on display.

 
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For those of you who forgot, here's our 2012 airshow presentation of The Horsemen. For this show, they used two P-51s and our P-38. Our P-38 had a newly-overhauled left engine at the time.


You can hear the "whistling" of the two P-51s quite clearly.
 

As noted above, indicated airs speed (IAS) of 420 mph means, at 10000 ft, true air speed (TAS) of 460 mph. Limit at 30000 ft was 290 mph IAS, or 440 mph TAS. Why such a low dive limit? Going by what was stated in the flight manual, the central pod and nacelles formed the venturi that inceased speed of local airflow. Coupled with non-adventurous wing thickness (eg. 16% at root) the wing section between nacelles and pod easiley went into compressibility. We can note that eg. Corsair and Bearcat, with even thicker wings, that belonged to the same family of airfoils (NACA 5-digit 230 series), have had better dive limit speeds.
The thread dedicated to dive speed limits is here: link

One, if not major reason why P-47N was that faster than P-47D was the new model of turbocharger, with greater speed allowed than it was with P-47D, rasing the rated altitude of engine by many thousands feet - thinner air allowed for greater speed, and there was also a 200 HP surplus vs. P-47D under same conditions.

P-51 used a far better wing, a far better layout of coolers, it was much smaller aircraft, there was no engies/nacelles sticking out in the wing. No wonder it was a speedy aircraft, especially once 2-stage Packard Merlin was installed. The P-51H was a brand new aircraft vs. P-51D/K, with aeorynamics perhaps 2 generations ahead vs. P-38, with much more engine power than older Mustangs, so performance went up accordingly.
 
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I will have to go back and look at my sources, but I counted 10. Now some of those may be listed as airworthy, but are not as in the case of Yanks at Chino. Then yeah I would agree it is less.
 

Actually, there was a greater difference in engine powers of the P-47D and P-47-M/N at high altitudes.
If water injection was used, the engine of the -D was capable to make 2200 HP at 29500 ft (link) with max ram (= max level speed). The engines of the -M/N were making 2800 HP at that altitude. Without water injection and with max ram, the -D have had 1500 HP at 36000 ft, the -M/N was with 2100 HP.

For comparison sake - P-38J/L was with 2x1600 HP at 29000 ft (max ram). At 36000 ft how much - 2 x 1000?
 
Hi Adler,

If you come up differently, I'd love to know who the others are. I would be WAY cool to get a complete gathering together!

Unlikely as hell, but we can always wish for it. They had a gathering of Mustangs some years back at Oshkosh and boatload showed up. At the Planes of Fame, we had some 18 P-51s at a recent airshow ... about 2011 or so. It was pretty neat to see how "stock-looking" these babied planes were. Really good crafsmanship and care.
 
I found this just after the first posting i did... LOL I sort of guessed part of the reason air racers didn't use the P-38 is two engines is a lot of extra work for privateers, even the USG seemed happier to make cheaper Mustangs in the end, i guess even the monster Tbolt is much cheaper to build.

 

Here is what I have as airworthy. If some of these are no longer airworthy please correct me.

1. 44-53254 "White Lightning"
Flying Bulls Lockheed P-38 Lightning - Hangar-7

2. 41-7630 "Glasier Girl"
Aircraft | Glacier Girl |

3. 42-12652 "White 33"
Westpac Restoration - P-38 White 33

4. 44-2314 "22 Skidoo"
PLANES OF FAME - Flying & Static Aircraft

5. 44-26981
Allied Fighters

6. 44-27953 "Relampago"
P-38 Lightning at War Eagles Air Museum

7. 44-27083 "Tangerine"
Aircraft List

8. 44-27183
Yanks Collection

9. 44-2731 "Scat III"
Fagen Fighters WWII Museum - Granite Falls, MN

10. 44-59035 "Thoughts of Midnite"

So unless some of these are no longer airworthy that makes it 10 P-38's flying today.

The only one I personally have seen fly is the Red Bull one at an airshow in Germany.

WestPac, Artemis and Collings Foundation are currently restoring 3 more to airworthy status.
 
The one at Yanks doesn't fly. That is the "flyable" Chino bird I was talking about. This one COULD be made flable, but it would take some doing, and the Yank's Air Museum owner isn't eager to fly any of them, ever. The only time I have ever seen one fly in 10 years is when they got a Lockheed Constellation EC-121 and it flew into Yanks and has been sitting ever since. I've never actually seen any of their birds commit aviation.

Allied Fighters is the former "Honey Bunny," also at Chino.

So, I didn't have the War Eagles Museum bird, and that makes 9 total.

Pretty cool to find another one. I'll have to ask Joe Yancey and see if he has engines in it.

Thanks, Adler!

I understand some 2 - 3 more are "in work," with no ETA for 1st flight. Would be great to see some more.
 


The only difference between the "F" and later cowlings are the intercooler cores between the oil coolers. Since this aircraft (N25Y) doesn't have turbos (not even non-functional units) on it there's very little point to having the intercoolers. The reason for the switch from wing leading edge skin coolers to conventional core coolers was because the earlier system was prone to debilitating leaks which limited horsepower because of the resulting low boost pressures.
 

No, it was because the leading edge intercoolers had insufficient cooling capacity, so the engine intake air was hotter and not as much boost could used, meaning lower power.
 
The main reason for the switch was due the old coolers in the wing leading edges being able to support less HP than the Allison engine could produce. They could only support 1050 HP before the temps started rising. After that, it was only a matter of time and temp. before you were hosed ...
 
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