On big American fighters

[Shortround6]

Hmm perhaps. If only looking at aircraft going to Brit/Commonwealth units, it's still useful for the planners to consider all the aircraft being ordered (Hurricanes, Warhawks, Mustangs) and manage allocation/distribution of resources accordingly. Overboosting/WER would have been a bonus after the fact, but potentially sacrificing hurricane performance in favor of Warhawk/Mustang performance would be the more serious initial consideration.

British figured in 1940 that a Hurricane II with a Merlin XX engine would be in the game (competitive) with a 109E. Without it it would have trouble. A Hurricane IIA with eight guns went about 7100lbs clean at take-off or about 900-1000lbs more than a Spitfire II and over 650lbs heavier than a Spitfire V with eight .303s. (roughly 10%). It was about 1 minute slower to 20,000ft than the MK V Spit. Fitting it with a lower powered engine would be consigning it to an even more second class status than it had. The Great Hope (Typhoon) was late in coming. Without Hurricane IIs to help take up the slack Britain would have been rather short of fighters in 1941. The Hurricane IIs could be shuffled off to other theaters. Germans changed the game by not just stuffing a slightly better engine in the last of the 109Es but coming out with the 109F.
The US cannot supply any (or more than a handful/count on one hand) of Packard Merlins until the start of 1942. Hurricane II production is well established at that point. Americans are 'hoping' the P-40F will solve part of their altitude problem.
The British had ordered 320 Mustang Is in May of 1940, well before first flight. They ordered another 300 in Sept of 1940, first production plane was rolled out factory door April 16th 1941, last of the 620 is rolled out in July of 1942. Another month sees only 4 British squadrons operational on the type. Too much di nking around with engine installations is only going to delay things. BTW July of 1942 saw NA get a contract to convert two lend-lease P-51s to XP-78s using Packard Melrin engines with 2 stage superchargers, later re-designated XP-51Bs. There is just not a lot of time to squeeze in single stage Merlin powered Mustangs without affecting delivery of the Allison powered ones or delaying the P-51B.
There was an order for 1200 Allison powered P-51As placed in June of 1942, In Dec it was cut to 310 planes, the balance of the contract was changed to P-51Bs join the contracts already in place for P-51Bs and Dallas built P-51Cs.

Using up engineering time to build a small (relatively speaking) batch of single stage stage Merlin powered Mustangs was probably not a good use of resources.

The drag comparison here is for the R-1830 and not R-1820 powered P-36, I assume. And aside from the possibility of using a 2-stage R-1830 (with or without adapting a tighter cowling and fan), the Allison seems to be preferable on the whole. (you might manage to save some weight -and gain climb- with a single stage R-1830 ... maybe even the 2-stage, not positive there)

Still, compared to the P-40B/C/D/E (especially before WER clearance), a 2-stage twin wasp powered P-36 (or P-42) seems like it'd have some advantages above 10,000 ft.

Yes the drag comparison is for the R-1830 powered P-36 as used by US forces. The Cyclone powered version was only used as trainer by the US after the US picked up a few foreign ordered aircraft that were undeliverable due to original country being over-run. The US Army didn't do much in the way of testing the Cyclone powered version/s.

The two stage Wasp was rated at 1200hp for take-off and 1100hp at 3500ft (aux blower disengaged), 1050hp at 11000ft (low gear in Aux blower) and 1000hp at 19,000ft (hi gear in aux blower). The so called "Normal" and Military ratings appear to be the same. 2700 rpm used for take-off doesn't seem to be allowed in flight. The Allison in the P-40D/E was good for around 1000hp at 15,000ft falling to around 800hp at 20,000ft. the P W isn't going to much, if any, advantage until it is over 15,000ft and the higher it goes the better.
Trouble with the 2 stage is what is the drag penalty over and above the single stage R-1830 below 10-12,000ft?

You can't equip a squadron with 2 sets of fighters and use the one best suited to the mission of the day.

 

[Shortround6]

neil...your second scan about spark plugs....i remember my father talking about the subject years ago. the plugs the fighter groups ( merlin mustangs ) were supplied withtended to foul up with lead after aggressive flying. they switched to a plug from another country to remedy the problem. i thought he said the originals spares were a uk plug and they switched to an american plug (AC delco ) but i may not have heard him correctly. but i do know the the different plug did not foul out nearly as bad as the original. i tried talking to a couple crew chiefs a while back but could not get confirmation one way or the other. do you happen to know what brand they were using as replacement plugs? i am assuming the originals the engines had when shipped from the us had american plugs...after that ???

It might depend on theater?

 

[Neil Stirling]

Hi bobbysocks,

Not 100/130 but 100/150 that contained even more lead, 6cc Tel per US Gallon.

Instructions for Modification of P-51 Airplanes For Project PPF.

Preferred plugs:

Best service, Lodge RS5/5 (GB)
Second best, KLG RC5/3 (GB)
Also satisfactory, LE44 (USA) when available.

Neil.

 

[kool kitty89]

Using the WI instead of inter-coolers does indeed offer some benefits, but also some shortcomings. WI is mostly used for WER; the inter-cooler is useful not just for WER, but also for making military power (= of longer duration). It is much easier to retrofit water injection on an inter-cooled engine (for even more power) than it is to retrofit inter-coolers on the engine that are not designed for it from get-go. The V-1710 flew as inter-cooled engine in 1939 in the XP-38, granted those were air-to-air inter-coolers;it took until 1943 for the 2-stage V-1710 to have WI installed.

I was suggesting retro-fitting (and/or adding in the factory) water injection for the existing turbocharged pre-J model P-38s that had detonation/manifold temperature problems due to limited intercooling on up-rated engines.

The US cannot supply any (or more than a handful/count on one hand) of Packard Merlins until the start of 1942. Hurricane II production is well established at that point. Americans are 'hoping' the P-40F will solve part of their altitude problem.

Wouldn't an Allison engined Hurrican evaluation aircraft at least be a worthwhile consideration? Not just in terms of re-allocating Ammerican merlins, but in the potential event that there might be further delays/shortages in Packard merlin production.

 

[Shortround6]

I was suggesting retro-fitting (and/or adding in the factory) water injection for the existing turbocharged pre-J model P-38s that had detonation/manifold temperature problems due to limited intercooling on up-rated engines.

you have to find space for the water injection. Corsairs only carried around 10 gallons? P-47s carried over 25 gallons.

Wouldn't an Allison engined Hurrican evaluation aircraft at least be a worthwhile consideration? Not just in terms of re-allocating Ammerican merlins, but in the potential event that there might be further delays/shortages in Packard merlin production.

When and why? Allison has no spare production capacity in 1940 and early 1941. The Allison is offering about 150hp less for take-off and about 100hp less at 11-12,000ft than the Merlin. And 250+ less HP at 18,5-20,000ft.

At least until the summer and fall of 1942 with the new Allison and the approval of WER ratings. Engine in the P-40K gets 1325hp for take-off but the altitude performance doesn't change much. Might have been a good engine for Hurri-bombers but in the 2nd half of 1942 Packard was pumping out 800 engines a month. Enough that shorting Canadian Hurricane production wasn't a problem.

 

[drgondog]

I also believe Pete Law, who knows more about aircraft piston engines than anybody in here. He has over 20 Reno wins as the engine guy, still consults for the Lockheed Skunk Works, and is as much of a walking authority as there is about aviation piston engines. His credentials are impeccable. So are Tony's.

.

I forgot to mention - despite your good friendship with Pete Law, you really 'shorted' his experience and expertise.

Law IIRC was a primary specialist in Thermo and Intake Design for Lockheed before being snapped up by Kelly for the SR-71 program - He remained with the Skunk Works until his retirement.

Then there is Bruce Boland, whom you didn't mention. Boland was also long time chief of Aero at Skunk Works and The guy for aero consulting for Dago Red, Strega, Red Baron, etc before he passed away. He forgot more aero than I ever knew.

 

[Shortround6]

The thing with recollections by individuals is that they often give a "snapshot" into a situation. Going with the P-38 and some hypothetical Veterans lets look at a particular problem. How to Cruise the P-38.

Veteran A says that the P-38 should be cruised at high RPM and low boost, that is the way he did it.
Veteran B says that the P-38 should be cruised at low RPM and high boost, that is the way he did it.

We have two different methods.
Veteran C says that the P-38 should be cruised at high RPM and low boost, that is the way he did it.

It is now 2 to 1 for high rpm and low boost.

Tony LeVier comes in and gives a talk and says that they were using the high RPM and low boost method in Europe against the instructions/advice of both Allison and Lockheed BUT changed during/after his tour in England demonstrating P-38 flying techniques.

IF veterans A and C were flying before Tony LeVier showed up in Europe and veteran B was flying after you have a situation in which veterans A and C were telling you their experience to the best of their knowledge. They are not lying or mis-remembering but repeating bad information they were given at the time. Veteran C was doing the same thing (telling you his experience to the best of his knowledge) but his "snapshot" is later in time. Tony LeVier had the knowledge to tie the stories together.

Enjoy the stories the remaining veterans can tell and honor them for the sacrifices/contributions they made.
But remember that a lot them were not engineering officers or had limited contact with factory representatives and some of their knowledge comes from "hanger talk" or instructors that were only a few years older than they were and like the case of how to cruise a P-38, the army instructors did not always get it right.

 

[FLYBOYJ]

This has been interesting reading, now I have to jump into the "I knew who" fray.

After Tony LeVier retired, he worked as a safety consultant for Lockheed and started a consulting agency called "SAFE" (I don't remember what the acronym meant). His office was inside the old A1 plant right across from the entrance to Hollywood/ Burbank airport. My ex-wife was a secretary for Lockheed Field Service and had an office right next to Tony's so we spent a lot of time with him, actually went to lunch with him a few times. I first met Tony at a retirement party in 1982. He allowed me to chew his ear off with questions from everything P-38 to F-104. I was surprised that when I reconnected with him in the later 80s he still remembered me. I did an extensive interview with him and it was published in "Aerotech News and Review" around 1989/ 1990. A few things I remember Tony mentioning a that will put all this into perspective;

"Low RPM (IIRC 1600 RPM) high boost, auto lean, just like Lindberg suggested".

At least a few hundred hours of twin time was needed to fully master the P-38. The ETO brass did not like the aircraft.

The engines were government furnished. Any modifications had to be run through the government and Allison for approval, so changes weren't always quickly forthcoming.

There were many things that Kelly Johnson wanted to do to the P-38 but wasn't able to because of war demands. I remember Tony mentioning that Johnson wanted to put a stick in the P-38 and get rid of the yoke.

I'll try to dig though some of my old stuff to see if I could find the article.

 

[gjs238]

This has been interesting reading, now I have to jump into the "I knew who" fray.

After Tony LeVier retired, he worked as a safety consultant for Lockheed and started a consulting agency called "SAFE" (I don't remember what the acronym meant). His office was inside the old A1 plant right across from the entrance to Hollywood/ Burbank airport. My ex-wife was a secretary for Lockheed Field Service and had an office right next to Tony's so we spent a lot of time with him, actually went to lunch with him a few times. I first met Tony at a retirement party in 1982. He allowed me to chew his ear off with questions from everything P-38 to F-104. I was surprised that when I reconnected with him in the later 80s he still remembered me. I did an extensive interview with him and it was published in "Aerotech News and Review" around 1989/ 1990. A few things I remember Tony mentioning a that will put all this into perspective;

"Low RPM (IIRC 1600 RPM) high boost, auto lean, just like Lindberg suggested".

At least a few hundred hours of twin time was needed to fully master the P-38. The ETO brass did not like the aircraft.

The engines were government furnished. Any modifications had to be run through the government and Allison for approval, so changes weren't always quickly forthcoming.

There were many things that Kelly Johnson wanted to do to the P-38 but wasn't able to because of war demands. I remember Tony mentioning that Johnson wanted to put a stick in the P-38 and get rid of the yoke.

I'll try to dig though some of my old stuff to see if I could find the article.

Good stuff - thanks!

 

[gjs238]

A few things I remember Tony [LeVier] mentioning a that will put all this into perspective; "Low RPM (IIRC 1600 RPM) high boost, auto lean, just like Lindberg suggested".

What was the timing of Lindberg's suggestion, which if I remember correctly was in the context of the PTO, vs events unfolding in the ETO?

 

[pbehn]

What was the timing of Lindberg's suggestion, which if I remember correctly was in the context of the PTO, vs events unfolding in the ETO?

from wiki

In his six months in the Pacific in 1944, Lindbergh took part in fighter bomber raids on Japanese positions, flying 50 combat missions (again as a civilian).[169] His innovations in the use of Lockheed P-38 Lightning fighters impressed a supportive Gen. Douglas MacArthur.[170] Lindbergh introduced engine-leaning techniques to P-38 pilots, greatly improving fuel consumption at cruise speeds, enabling the long-range fighter aircraft to fly longer range missions. The U.S. Marine and Army Air Force pilots who served with Lindbergh praised his courage and defended his patriotism.[168][171]

 

[gjs238]

1944, wow
It took sooo long to resolve something that should have/could have been resolved so much sooner.

 

[FLYBOYJ]

What was the timing of Lindberg's suggestion, which if I remember correctly was in the context of the PTO, vs events unfolding in the ETO?

Tony was in Europe with "Snafuperman" right before D day. He made it appear to me that this should have been known when the P-38 entered service in mass.

 

[Shortround6]

To some extent.

There may be more than one thing going on. The low RPM/high boost issue maybe different than manual leaning (vs using auto-lean) of the engine/s once the low rpm/high boost option is selected.

Then you have the Cruising speed issue. The higher throttle settings needed for escort work may be different than the cruise settings when being used as a fighter bomber?

http://zenoswarbirdvideos.com/Images/P-38/38FOIC.gif

 

[pbehn]

To some extent.

There may be more than one thing going on. The low RPM/high boost issue maybe different than manual leaning (vs using auto-lean) of the engine/s once the low rpm/high boost option is selected.

Then you have the Cruising speed issue. The higher throttle settings needed for escort work may be different than the cruise settings when being used as a fighter bomber?

http://zenoswarbirdvideos.com/Images/P-38/38FOIC.gif

That was how I remember it being discussed on a programme about Lindbergh, everyone was worried about running for long periods with a very lean mixture boost levels and RPM wernt mentioned but TV programmes tend to dumb down a bit.

 

[kool kitty89]

1944, wow
It took sooo long to resolve something that should have/could have been resolved so much sooner.

That was how I remember it being discussed on a programme about Lindbergh, everyone was worried about running for long periods with a very lean mixture boost levels and RPM wernt mentioned but TV programmes tend to dumb down a bit.

I Wonder if the problem would have been recognized and addressed any sooner if the Lightning had been adopted (and more exhaustively tested) by the RAF.

The Allison engined aircraft they did recieve seemed to get fairly exhaustive testing with some notes beyond that the USAAC/AAF was doing, or at least beyond that the US was forwarding to standard squadron training. (the extreme range figures for the P-40B in testing seem to point to rather careful use of low RPM and full manual lean mixture control)

British reports remarked on the Allison's ability to operate smoothly at considerably lower RPM and somewhat leaner mixture than the merlin. I'm not sure if this resulted in such practices being used for long-range cruise in RAF/Commonwealth service, though.

Plus a somewhat different context given the more variable boost pressures possible on a turbocharged aircraft. (and relatively little power lost to the turbocharger through exhaust backpressure and the integral superchargers of P-38 Allisons -compared to the 8.8 or 9.6 supercharger gearing on P-40s and P-39s)

At least a few hundred hours of twin time was needed to fully master the P-38. The ETO brass did not like the aircraft.

The engines were government furnished. Any modifications had to be run through the government and Allison for approval, so changes weren't always quickly forthcoming.

There were many things that Kelly Johnson wanted to do to the P-38 but wasn't able to because of war demands. I remember Tony mentioning that Johnson wanted to put a stick in the P-38 and get rid of the yoke.

I've read about the yolk vs stick issue several times before and it does seem rather unfortunate even from a paractical standpoint alone. (aside from being easier for fighter pilots to transition to, a stick clutters the cockpit much less, giving easier view to the complex array of instruments lining the P-38 dashboard and a stick might have given more leverage to operate the heavy ailerons on early non-boosted models)

Aside from that, the mention of political issues and UTO brass disliking the P-38 in general might be relevant to question I posed in the RAF day bombing thread, but is probably more relevant here:




From: http://www.ww2aircraft.net/forum/av...ng-campaign-results-42824-11.html#post1191095

Hmm ... shifting the topic a bit, but still somewhat relvant: in terms of similar manufacturing cost/resources, would ordering more early model P-38s (or modified turbo-less ones) have been more useful than similar resources going into P-39 and/or P-40 production? (this includes potential use as a medium altitude escort fighter)

In terms of sheer logistics would the P-38 have made more sense to produce in quantity (with or without turbos) in place of the P-40 and P-39 in roughly half the numbers? (maybe slightly more than that if outsourced production had transitioned efficiently enough and allowed relatively streamlined production of a single type -or variants of a single airframe -including changes required for an actually practical non-turbocharged variant, unless engine production becomes the bottleneck in which case it'd be exactly half)


The P-38 had the capacity for 2 to 4 times the bomb load of the contemporary P-40 and P-39 along with considerably longer range at the same time throughout its production. (more than double the bomb load and double the range -with load- in some configurations) On top of that it had a heavy, tough airframe and twin engines making for better survivability. Then the generally superior armament to either of those single engined contemporaries (be it guns used, concentration of fire, rate of fire, or ammunition capacity, there's a list of advantages -not to mention configuring the 20 mm cannon with a cocking mechanism allowing jams to be cleared by the pilot in-flight)

With similar ram intake and short exhaust stacks optimized on the P-40 and P-51, low/medium altitude turbo-less P-38s likely would have been generally more capable aircraft than similarly powered P-40s and P-39s (and better fighter-bombers than allison P-51s). Possibly better low-altitude performers than their turbocharged counterparts (at least early on) and potentially able to be equipped with the wing tanks in place of the intercoolers. (or at very least saving weight from the removal of turbos, intercoolers, and related exhaust and induction ducting) On top of that, the early P-38's problems were considerably less pronounced in low/middle altitudes and those ranges were far more often flown in the PTO and (especially) MTO as it was.

With the P-38s historically costing around double that of P-40s and P-39s (perhaps a bit less for turbo-less models), it seems like they'd still be more valuable engine per engine and pound per pound than their single engine counterparts. The performance on top of the sheer versitility of the arcraft to accomplish nearly anything the P-40 or P-39 could do ... or often what it might take two of them to achive, in addition to long range work totally impossible for either of the others to accomplish, it just seems a more valuable overall aircraft.

The only other logistical problem comes down to pilot training. You'd only need to train around half the pilots, but each pilot would need a considerably greater investment made in their training compared to the P-39, P-40 or the other single engine US fighters. (P-40 more so than P-39 given the handling characteristics) Granted, omitting turbo controls would simplify matters somewhat and simplify some aspects of training compared to the P-47 (plus lack of need to compensate for engine torq in normal operation), but twin-engine training in general would be the major hurtle.

That still may have been logistically less costly than training double the number of single engine pilots but leaves less room for error in questionable training. On the other hand, average P-38 pilot competency than happened historically may have been better if such emphasis was put on twin engine training.


Anything along this line would also likely be in exception to the P-40/A/B (and Tomahawks) but possibly supplanting P-39D and P-40D production depending how fast the transition to P-38 production actually took place. (the P-38 would have to be a surefire design before distributed/expanded priority production even made sense, lest they have delays that lead to having too few servicable aircraft early-war)

With the P-40's earlier initial production, friendlier handling, longer range, generally better reputation among pilots and crew, and older, proven airframe, keeping that aircraft as the main early 'backup' fighter would have made sense to keep production up until the P-38 was really proven. (and before the Mustang reached mass production) While cancelling the P-39 outright (export orders notwithstanding) in favor of second-sourced P-38 production seems somewhat viable, political issues with Lockheed-Bell cooperation notwithstanding. That and the P-40F and L wouldn't be competing with P-38 engine production either. (aside from the separate topic of those engines being more valuable if mated to P-51 airframes)


Delays in the P-38 testing program with the crash of the original prototype along with the unfortunately lacking modifications made for the non-turbocharged Lightning I hamper the viability for this to have happened. A better performing Lighting I (or at least an improved follow-on) along with more aggressive early testing to work out the major bugs in the initial P-38 design would have all made its merits more clear as a domestic and export aircraft. (to the point the British may have seen it as genuinely worthwhile over purchasing double the P-40s and P-39s)

 

[drgondog]

The only other logistical problem comes down to pilot training. You'd only need to train around half the pilots, but each pilot would need a considerably greater investment made in their training compared to the P-39, P-40 or the other single engine US fighters. (P-40 more so than P-39 given the handling characteristics) Granted, omitting turbo controls would simplify matters somewhat and simplify some aspects of training compared to the P-47 (plus lack of need to compensate for engine torq in normal operation), but twin-engine training in general would be the major hurtle.

Simply stated - the P-38 was 2x as expensive to operate (fuel/oil), 2x as expensive as the Merlin P-51, 1.5-2x more expensive in Inventory management. - all major negative factors even for a resource rich US trying to provision globally

That still may have been logistically less costly than training double the number of single engine pilots but leaves less room for error in questionable training. On the other hand, average P-38 pilot competency than happened historically may have been better if such emphasis was put on twin engine training.


Anything along this line would also likely be in exception to the P-40/A/B (and Tomahawks) but possibly supplanting P-39D and P-40D production depending how fast the transition to P-38 production actually took place. (the P-38 would have to be a surefire design before distributed/expanded priority production even made sense, lest they have delays that lead to having too few servicable aircraft early-war)

The P-38 development was severely hampered for a couple of reasons - first the delay in recognizing the aerodynamic issues as well as the high altitude turbo/intercooler/engine problems until the P-38J was in production. Second - Lockheed didn't get the funding necessary to acquire tooling and facilities for EFFICIENT mass production until late 1942. Contrast that with the A-36/P-51A contracts which funded mass production on a far larger scale than the P-38, which also drove the unit cost down.



With the P-40's earlier initial production, friendlier handling, longer range, generally better reputation among pilots and crew, and older, proven airframe, keeping that aircraft as the main early 'backup' fighter would have made sense to keep production up until the P-38 was really proven. (and before the Mustang reached mass production) While cancelling the P-39 outright (export orders notwithstanding) in favor of second-sourced P-38 production seems somewhat viable, political issues with Lockheed-Bell cooperation notwithstanding. That and the P-40F and L wouldn't be competing with P-38 engine production either. (aside from the separate topic of those engines being more valuable if mated to P-51 airframes.)

in 1942, because of all the attributes you cited, the demand was high for the P-38 despite the many flaws. It was pulled from ETO to support Africa campaign, and denied to PTO until 1943 for the same reasons - but the demand flowed to keep the P-40s and P-39s in production simply because our armed forces and Commonwealth/USSR allies needed critical mass in the fighter bomber role - which P-38 production couldn't solve until 1944.


Delays in the P-38 testing program with the crash of the original prototype along with the unfortunately lacking modifications made for the non-turbocharged Lightning I hamper the viability for this to have happened. A better performing Lighting I (or at least an improved follow-on) along with more aggressive early testing to work out the major bugs in the initial P-38 design would have all made its merits more clear as a domestic and export aircraft. (to the point the British may have seen it as genuinely worthwhile over purchasing double the P-40s and P-39s)

What they saw in 1941 convinced them that the P-38 a.) was not ready for combat in the ETO, b.) was not a good value based on price and logistics - at that time, and c.) its promise and potential as a long range escort didn't fit the RAF model for strategic bombing.

IMO had the P-38J emerged in early 1942, reached ETO by early 1943 instead of the P-47, the history of the P-38 would have changed for the better.. but as a great fighter, it didn't exist until mid 1944

 

[gjs238]

The shame though is that the P-38 was highly valued and sought after in PTO, but was not available in sufficient quantity.

 

[tomo pauk]

Again, several things need to happen for more/debugged P-38s: having a second source of production; not crashing the XP-38 (at least not that early); USAAF contracts Lockheed for more pre-series examples earlier.

 

[gjs238]

Was it common to have just one prototype?