1942 and on: RAF fields 'proper' P-38s - consequences?

[gjs238]

I imagine the Brits would have liked using the Lightning for Rhubarbs.

 

[ShVAK]

I imagine the Brits would have liked using the Lightning for Rhubarbs.

Makes sense, that's what the Westland Whirlwind was commonly used for. I imagine having two engines, even liquid-cooled ones (just opened a can of worms there ) would be a boon for ground attack operations. Wonder how well a P-38J modified with two or three British 20mm H-S's in the nose and some HVAR/RP-3 racks would've done.

 

[michaelmaltby]

Rhubarbs ....

"... A little-known role of the P-38 in the European theater was that of fighter-bomber during the invasion of Normandy and the Allied advance across France into Germany. Assigned to the IX Tactical Air Command, the 370th Fighter Group and its P-38s initially flew missions from England, dive-bombing radar installations, enemy armor, troop concentrations, and flak towers.[61] The 370th's group commander Howard F. Nichols and a squadron of his P-38 Lightnings attacked Field Marshal Günther von Kluge's headquarters in July 1944; Nichols himself skipped a 500 lb (227 kg) bomb through the front door.[62] The 370th later operated from Cardonville France, flying ground attack missions against gun emplacements, troops, supply dumps and tanks near Saint-Lô in July and in the Falaise-Argentan area in August 1944.[61] The 370th participated in ground attack missions across Europe until February 1945 when the unit changed over to the P-51 Mustang."

[Wikipedia]

... I've always liked rhubarb

 

[wmaxt]

I don't really know if "Proper" P-38's would have had much of an impact in British hands only because by the time the F-15 with combat flaps was delivered we were in the war and starting to take the load from them.

Before the J-25 was produced the yoke was needed to give the pilot a bit of extra leverage for aileron deflection at higher speeds.

According to a number of sources compressibility was not an issue below 20,000ft. To Quote Hurlbut Co 82nd FG When we were dive bombing we rarely started from less than 12,000ft because the 38 accelerated to fast to get lined up properly and even more rarely from above 20,000ft so we could avoid compressibility. Thats one reason why you never hear of complaints about compressibility anywhere but the ETO where the norm was to fly from 25,000ft and higher.
Another was that when the pilots the the Pacific and the Med dove from higher than 20,000ft the would pill back their throttles and put the props into a flat pitch and if needed rock the wings to add drag which would keep the aircraft to a controllable speed by enough margin to get out of the dive when required as related by a pilot of the 475th FG.
According to Warren Bodie Lockheed test pilots never encountered Compressibility if the dive started from 25,000ft or below.

The P-38 was great at ground attack and could carry a greater load that either the P-47 or the P-51. There are many photos of P-38 F to Js with field installed bomb shackles, up to 4, so that they could carry 6 500lb bombs at a time in the PTO and MTO. All P-38s were cleared to carry 2 300gal drop tanks (about 2,000lbs each), with speed restrictions, so weight carrying ability was not an issue. The H and J models were officially rated at 3,2oolbs a limit imposed by the stock pylons and aerodynamic issues. Later P-38Ls were reported to have flown with two 1,000lb bombs and ten 5" rockets a 5,000lb load.

Bill

 

[Shortround6]

The Mustang was built to British specifications and hundreds were purchased from 1941 onward. What can a P-38 do that a Mustang cannot?

The early P-38s could fight at 20-30,000ft which the Allison powered Mustangs could not do.

"By July of 1941, the RAF recognized that there probably would be a need for high altitude capabilities, and the original contract was amended to provide for the delivery of 143 Lightning Is (British military serials AE978/999 and AF100/220) with the originally-specified V-1710-15 un-turbosupercharged engines, with the remaining 524 aircraft (serials AF221/AF744) to be delivered as Lightning IIs (Model 322-60-04) with turbosupercharged V-1710-F5L and -F5R engines with guaranteed top speeds of 415 mph at 20,000 feet."

"The first three Lightnings arrived in the UK by sea transport in March of 1942"

Both quotes from Joe Baugher's web pages.

It isn't until the end of April or into May of 1942 that the "Idea" of the Merlin powered Mustang begins to pick up any steam. And Merlin 60 series engines aren't exactly lying around unused either. First Production Merlin Mustang doesn't fly until May of 1943 and first Dallas built plane flies in August.

Turboed P-38s could have been in British use ( in small numbers) around 9 months to year before the Merlin Mustangs showed up.

 

[wmaxt]

It wasn't until mid 1943 that the British found out what a real P-38 could do.

Test No 56 Duxford Station 1943

Note 46. The P-38 for a twin engine fighter is extremely maneuverable.
Note 47. The P-38 has a fast rate of roll and a good stall allowing the pilot to get the best out of it in combat.
Note 47. Tested with a Spitfire IX at various altitudes the Spitfire was slightly superior in turning radius at all altitudes
Note 49. it was found during trials the P-38 had difficulty keeping his sights on the Spitfire due to its superior turning radius and the Spitfire had difficulty allowing the correct lead on the P-38 and at times was considerably upset in the turbulence which was considerable.
Note 50. The Spitfire accelerated better that the P-38 at various altitudes.
Note 51. The Spitfire was behind the P-38 when the P-38 rolled over on its back and pulled out in a three-quarter roll, when the Spitfire followed the pilot blacked out and was forced to break off the attack.

There is more and these notes are excerpts. If I can I will scan and post the test. but it is very faint and have had no luck so far.

The P-38s were up to the task but they never really tried to use them.

The British custom ordered two aircraft from the US factories the P-38 with down rated engines and no turbo's and the Allison Mustang - and they didn't like either though in their final form they were both war winners!

Bill

 

[Shortround6]

The British custom ordered two aircraft from the US factories the P-38 with down rated engines and no turbo's and the Allison Mustang - and they didn't like either though in their final form they were both war winners!

Bill

Thank you for your work in typing up those notes.

The British did order a large number of P-38s with the down rated (old C-15) engines, but due to circumstances only 3 were delivered.
Allison Mustangs were disliked enough to have 2 squadrons still using them over what was left of Germany in April 1945, over two years after the last one rolled off the production line. It might not have been a mid to hi-altitude fighter ( but neither was the Typhoon/Tempest) but is seems to have been liked well enough for what it could do.

 

[fastmongrel]

The British custom ordered two aircraft from the US factories the P-38 with down rated engines and no turbo's and the Allison Mustang - and they didn't like either though in their final form they were both war winners!

Bill

Not true the RAF absolutely loved the Allison Mustang, Army Co-operation squadrons kept them flying till they ran out of parts. The last Allison models werent struck off charge till early 1945 not bad for an aircraft that would have been built in 1941 or 42.

edit: Doh beaten by SR6 must learn to type faster

 

[wmaxt]

Pilots liked it to a point but overall it wasn't enough better than the P-40 to stay in production. In October, November and December 43 the factory sat idle. At about that same time the Merlin was was being considered for the P-51 which December, January time frame was installed and testing begun. There were not tremendous expectations the Merlin in the P-51, in the P-40 it was not the night to day conversion it was in the P-51 and the extra fuel tankage was not even contemplated until the Merlin/low drag/laminar flow wing showed what it was capable of.

I'm not running down the P-51 it was an exceptional aircraft.

Bill

 

[Shortround6]

"In August of 1942, 400 P-51Bs were ordered on the basis of NAA's performance estimates."

"The first XP-51B was flown by Bob Chilton on November 30, 1942."

"The first A-36A flew on September 21, 1942. Deliveries of the A-36A were completed by the following March."

"On March 11, 1941, the Lend/Lease Act was passed by Congress, permitting the "lending" of American-built aircraft to nations deemed "vital to the security of the United States". On September 25, 1941, the US Army ordered 150 Mustangs under the provisions of Lend-Lease for delivery to Britain. All previous RAF Mustangs had been direct purchases by Britain. These Lend-Lease Mustangs were designated Mustang Mark IA by the RAF and NA-91 by the factory. ......but this was changed to *Mustang* at about the time the deliveries began in mid- 1942."

Kind of reverse order but the factory was not sitting idle in October, November and December 42.

British were out of money, US Army was out of money for fighters which is why the A-36 designation.

P-40 used a single stage Merlin, P-51s used a two stage Merlin, difference at over 20,000ft was several hundred HP Like the difference between 1120hp at 18,000-18,500ft (no ram) and 1260hp at 26,000ft (climb ram) for a -3 Merlin. The -1 Merlin in the P-40 may have been down to 900hp at 26,000ft. Even if it still had 1000hp the -3 Merlin offered a good 25% more power than the -1 used in the P-40. Let alone what the power difference was between an Allison and an -3 Merlin at 25,000ft or so. Great things were expected from the Merlin Mustang even before it was flown as evidenced not only by the initial 400 plane order several months before the prototype flew but the tooling up of the Dallas factory to Produce Merlin Mustangs. First Dallas built plane flying in in Aug of 1943 which meant tooling up began months before.

" The huge Inglewood, California factory was greatly expanded and dedicated solely to Mustang production, with the B-25 Mitchell program being transferred to Kansas City."
"Production of the AT-6 series of trainers had earlier been transferred from Inglewood to a new plant built in great haste at Dallas, Texas. The USAAF instructed NAA to expand the Dallas plant even further as a second source for Mustangs."
"By the end of January 1943 the production standard for the P-51B/C had been decided"

That means all the redesign and re-stressing for the higher weights and power including upping the under wing ordnance from 500lbs each side to 1000lbs each side.

All lines in quotation marks form Joe Baughers web site.

 

[tomo pauk]

It wasn't until mid 1943 that the British found out what a real P-38 could do.

Test No 56 Duxford Station 1943

Note 46. The P-38 for a twin engine fighter is extremely maneuverable.
Note 47. The P-38 has a fast rate of roll and a good stall allowing the pilot to get the best out of it in combat.
Note 47. Tested with a Spitfire IX at various altitudes the Spitfire was slightly superior in turning radius at all altitudes
Note 49. it was found during trials the P-38 had difficulty keeping his sights on the Spitfire due to its superior turning radius and the Spitfire had difficulty allowing the correct lead on the P-38 and at times was considerably upset in the turbulence which was considerable.
Note 50. The Spitfire accelerated better that the P-38 at various altitudes.
Note 51. The Spitfire was behind the P-38 when the P-38 rolled over on its back and pulled out in a three-quarter roll, when the Spitfire followed the pilot blacked out and was forced to break off the attack.

There is more and these notes are excerpts. If I can I will scan and post the test. but it is very faint and have had no luck so far.

The P-38s were up to the task but they never really tried to use them.

The British custom ordered two aircraft from the US factories the P-38 with down rated engines and no turbo's and the Allison Mustang - and they didn't like either though in their final form they were both war winners!

Bill

Thank you for your work in typing up those notes.

The British did order a large number of P-38s with the down rated (old C-15) engines, but due to circumstances only 3 were delivered.
Allison Mustangs were disliked enough to have 2 squadrons still using them over what was left of Germany in April 1945, over two years after the last one rolled off the production line. It might not have been a mid to hi-altitude fighter ( but neither was the Typhoon/Tempest) but is seems to have been liked well enough for what it could do.

Indeed, thanks for the effort, Bill.

Just a note about the P-38s the British French ordered - they did not ordered the down rated engines, but the ones that were to be produced in 1940 - the V-1710 C-15s, same ones that were to power the P-40s, for the same customer (not only for them, of course). With turbo, those were capable for circa 100 HP more (1150 HP). Alas, the customer's request meant that the examples delivered were to be powered with 2 x 1040 HP, ie. turbo installation was not part of the order. Fine for 1940, but not for 1942, when the 1st examples of the Model 322 were tested at Boscombe Down. So the RAF turned down their order.
Again, the engines of the F series (where the reduction gear was capable to withstand more than 1200 HP, unlike the ones C series' reduction gears were capable to), like the F-5s that were powering the P-38Fs (1325 HP each engine, authorized from Aug 1942), were distant future in 1940.

 

[wmaxt]

I stand corrected on the P-51 seems there is as much bad info on it out there as the P-38. Though I do think there is more to it than plant modifications and there was no lack of money if the AAF really wanted it.

I was involved in an auto plant retooling/modification for a major model change at a GM plant, we did a running changeover with the plant only being down two weeks. There was no reason to stop production from that standpoint. The final design for the Merlin Mustang wasn't decided before the end of January then they re-stressed the aircraft. They couldn't even build the final tooling until the March time frame. The first P-51B came off the line in May. So I would believe there was more to it. I ran across J Baugher's P-51 site this morning and picked up some info that is new to me.

As for the P-38 You are correct Tomo. The 1710-C engines were 30-40hp less than the 1710-F engines used in the P-38 at that time this is why I used the term down rated.

I have difficulty typing at times so I sometimes truncate things.

Bill

 

[Shortround6]

I stand corrected on the P-51 seems there is as much bad info on it out there as the P-38. Though I do think there is more to it than plant modifications and there was no lack of money if the AAF really wanted it.

Congress appropriates the money. Maybe the AAF could have swapped money around but that means cutting another program unless they get MORE money from congress. Aircraft were being delivered 1-2 years after the appropriations were made. The first 524 or so P-40s were actually split over two fiscal years even though the order/s were placed the same day. Ordered in the spring (April 26) of 1939, the first production plane isn't delivered until April of 1940 (and the P-36 line already exists) and due to deferring delivers to France and England the order isn't completed until the summer of 1941.

I have difficulty typing at times so I sometimes truncate things.

Bill

I know what you mean, I had to go back and make about 8-10 correction just in the above.

 

[gjs238]

Allison Mustangs were disliked enough to have 2 squadrons still using them over what was left of Germany in April 1945, over two years after the last one rolled off the production line. It might not have been a mid to hi-altitude fighter ( but neither was the Typhoon/Tempest) but is seems to have been liked well enough for what it could do.

Grammy always said Rhubarb is good for you.

 

[gjs238]

Pilots liked it to a point but overall it wasn't enough better than the P-40 to stay in production. In October, November and December 43 the factory sat idle. At about that same time the Merlin was was being considered for the P-51 which December, January time frame was installed and testing begun. There were not tremendous expectations the Merlin in the P-51, in the P-40 it was not the night to day conversion it was in the P-51 and the extra fuel tankage was not even contemplated until the Merlin/low drag/laminar flow wing showed what it was capable of.

I'm not running down the P-51 it was an exceptional aircraft.

Bill

Did the P-40 and P-51 receive the same Merlins? I thought the P-40's received Merlins w/single stage superchargers.

PS: Just realized someone else addressed this in an earlier post.

 

[tomo pauk]

With RAF fielding the P-38F in 1942, the cockpit heater issues can be brought to the surface addressed earlier, so the USAAF has far smoother ride in the winter of the 1943/44. Maybe also a timely addition of a second generator?
Another problem that plagued the P-38J, would be also smaller with less efficient intercoolers, namely the fuel puddling due (among other causes) the mixture overcooling. The proper pilotage techniques (on cruising - low rpm, high manifold pressure) should still apply, if only for better mileage.

 

[gjs238]

With RAF fielding the P-38F in 1942, the cockpit heater issues can be brought to the surface addressed earlier, so the USAAF has far smoother ride in the winter of the 1943/44. Maybe also a timely addition of a second generator?

Weren't these issues being discovered and debugged in the Aleutians?

 

[Jabberwocky]

With RAF fielding the P-38F in 1942, the cockpit heater issues can be brought to the surface addressed earlier, so the USAAF has far smoother ride in the winter of the 1943/44. Maybe also a timely addition of a second generator?
Another problem that plagued the P-38J, would be also smaller with less efficient intercoolers, namely the fuel puddling due (among other causes) the mixture overcooling. The proper pilotage techniques (on cruising - low rpm, high manifold pressure) should still apply, if only for better mileage.

Turbo RPM and carburetor/intercooler problems also limited the engine power and combat ceilings on early Lightnings. The problem was still present on the P-38G in early to mid 1943. Absolute ceiling was close to 40,000 ft, but combat ceiling was only 35,000 ft according to USAAF tests.

You've also got problems with tail-flutter effecting the early sub-types, armament installation problems, as well as the aforementioned cockpit heating issues ect.

I don't think the P-38 is really combat ready until the P-38G appears from June/July 1942. If you look at the tactical trials, the G is much better than the F.

I don't think the P-38 would change the RAF's mind about the feasibility of long-range escort missions in daylight.

One of the other major rubs is logistics. Adopting a highly complex aircraft like the P-38 is going to take some serious engineering resources, particularly given the trouble related to the confluence of the GE turbochargers, the Allison engines, the English climate and the fuel/aromatics situation. Sections of the RAF wanted the Typhoon canned because the Sabre was such a resources hog. I wonder what said elements would do once the P-38 arrived?

There's also the question of airfields and operations. While it was fine on grass fields, the P-38 needed much longer take-off distances than the Spitfire or even the Typhoon, so the airfields it can operate from are going to be somewhat limited.

 

[tomo pauk]

Turbo RPM and carburetor/intercooler problems also limited the engine power and combat ceilings on early Lightnings. The problem was still present on the P-38G in early to mid 1943. Absolute ceiling was close to 40,000 ft, but combat ceiling was only 35,000 ft according to USAAF tests.

Intercooler issues were rectified only once the -J entered service, in late 1943. The 35000 ft of combat ceiling is only some 1500 ft lower than the Spit V?
With P-38s employed to protect Med convoys, the service ceiling is more than enough.

You've also got problems with tail-flutter effecting the early sub-types, armament installation problems, as well as the aforementioned cockpit heating issues ect.

I've mentioned the poor cockpit heater just two posts above, and contemplated that earlier recognition (winter of 1942/43, operations at ETO) handling of the issue would benefit the USAAF's operation of the P-38s during the winter of 1943/44.
The subtype that more or less satisfactory had the issue of the tail flutter solved (via installation of the wing fillets) was the P-38D, produced in 1941. So no such problems for the -Fs in 1942.
If you can point out what were the armament installation problems, I'd appreciate that.

I don't think the P-38 is really combat ready until the P-38G appears from June/July 1942. If you look at the tactical trials, the G is much better than the F.

The -F was the 1st fully capable P-38 - self sealing tanks installed, while from the -E the MGs are in staggered layout, allowing for greater ammo capacity. As for the -G being that better than the -F, the minor changes of the engine do not make that much of the difference. Again, I'd like to take a look at the tactical comparisons; the ones including the Spit IX and -F are not unfavorable for the P-38.

I don't think the P-38 would change the RAF's mind about the feasibility of long-range escort missions in daylight.

Think we can agree on that. It could make the path smoother for the USAAF, though.

One of the other major rubs is logistics. Adopting a highly complex aircraft like the P-38 is going to take some serious engineering resources, particularly given the trouble related to the confluence of the GE turbochargers, the Allison engines, the English climate and the fuel/aromatics situation.

Since the RAF's technicians (even those of the Indian air force) managed to get the grips of the 4-engined, turboed bombers, maybe the P-38 was well within their scope?
Fuel/aromatics situation Engilsh climate issues were compounded by wrong engine regimes used by USAAF pilots in winter of 1943/44 (high RPM, low MAP, instead vice versa) and the better intercoolers of the -J model. Applying proper cruise technique improves situation, and so do the less efficient intercoolers of the -F/G/H P-38s.

Sections of the RAF wanted the Typhoon canned because the Sabre was such a resources hog. I wonder what said elements would do once the P-38 arrived?

Maybe the crews commanders of the saved ships bombers (thanks to the fighter with a footprint) would had something to say? Let alone if the P-38 arrives via LL?

There's also the question of airfields and operations. While it was fine on grass fields, the P-38 needed much longer take-off distances than the Spitfire or even the Typhoon, so the airfields it can operate from are going to be somewhat limited.

With 2 x 150 gals of the external fuel, the P-38G have had the same take off distance as the P-40E with 75 gal drop tank (cca 1900 ft) - so no problems there.

 

[wmaxt]

Tomo, I agree with most of your post.

I agree with you that the P-38F was the first combat ready P-38 with the comment that it was a late P-38-15 with maneuvering flaps.

Tail flutter was indeed corrected with the wing to pod fillets in the D model though the AAF insisted on adding external counter balancers.

The early intercooler issues were much exaggerated by the AAF. Cpt Ben Kelsy the AAF project for the P-38 felt 54" MAP was a much more realistic limit and in combat most pilots pushed the pressure past the 44" the AAF test pilots recommended. I've read account of pilots hitting 86" in a P-38H - think of what the performance would be!

Pilot operation of the P-38 in the ETO had many problems. High RPM and low MAP led to:
1. Cold oil and poor lubrication leading to blown engines when the power goes up rapidly.
2. The cockpit hear was from drawing air across the exhaust pipe as it entered the heater ducting. The exhaust pipe isn't very hot in these conditions so the heat was degraded - not that it was very good at the best of times.
3. cold turbo's and turbo oil giving poor lubrication again causing lag and possible explosion when the power is quickly added.
4. Poor fuel usage larger boost ratings lead to greater cylinder pressures which equal better efficiency - more power and better fuel economy at the same time.

After Toney LeVier went to England in February/March and talked to then flew for the pilots showing just what a P-38 could do helped clear these issues up and the problems greatly diminished.

Above 30,000ft the high aspect elevator and narrow props lost effectiveness, the P-38 lost many of its advantages but could still hold its own. The P-38K would have corrected most of the problems, but was not approved by the WPB because the P-38 was considered to important to interrupt the delivery of two weeks production. The P-38K was tested in late '43, and according to the AAF "It far exceeded every other fighter the AAF had in every measurable performance category".

Bill