1 engine vs 2 engine fighters

pbehn said:

SR just covered it above, basically the plane could survive losing an engine if the enemy hit the engine that the designer wanted them to.
To run on one engine you need all the pumps and electrics to run and also the ability to take fuel from one side to the other.

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Actually it could survive loosing either engine, with some limitations. Here is an excerpt from Dr. Carlo Kopp in a technical report on the P-38:

"Another problem seldom mentioned was the single generator problem. If a generator was lost or a low battery the Curtis Electric prop would lose the Dynamic Brake and go to extreme Low Pitch. This was called a RUN AWAY. It could happen on Take Off with a low battery. Since you couldn't feather it set up a lot of drag making it difficult to make it around to land. The Killer situation was to lose the Generator or lose the engine with the Generator on it while 2 or 3hrs into Germany. Procedure was to SET the Props then turn off all electrical power. Then momentarily turn it back on to reset the props as needed. Being sure everything electrical was also turned off -- No Radios. The forgotten thing was you were at altitude and the OAT was -60degrees and the little old battery was cold soaked. Hence, dead as a dog. Result, with a lot of altitude you have less than an hour with one or two props in RUNAWAY.

The single generator was replaced with dual generators starting with the later "L" models but not on all of them. There were other mods made as well to make the aircraft more survivable. One significant one was the replacement of fuses by circuit breakers.

Robert Porter said:

Actually it could survive loosing either engine, with some limitations. Here is an excerpt from Dr. Carlo Kopp in a technical report on the P-38:

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Got mixed up in the conversation, I was only speaking in general terms Robert. Generally speaking, on a twin if there was anywhere to hit it that would knock both engines out then that would be where all stray bullets are attracted to.

Shortround6 said:

It may be more difficult. There is more stuff you have to change.

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Thanks for the answer S/R I guessed that it was more difficult simply because twin aircraft in general didn't change by a huge amount from first entering service but were replaced by re designed aircraft if a substantial change to the power plant was needed.

I think, for the US, the only twin engine planes to radically change engines were the Douglas A-20 from the P & W R-1830 to the Wright R-2600 and the champion of engine swaps. the Lockheed Super Electra/Loadstar. (or Lockheed 14/18) This airframe, with the aid of a fuselage stretch, went from P & W Hornets and Wright Cyclones to P & W twin wasps, later Cyclones, then R-2600s and finally R-2800s.

For the British the only large scale production twin engine aircraft I can think of offhand is the Wellington going from Pegasus engines to Hercules. Not sure how the Merlin Beaufighters rate as Merlins didn't really supply more power than the Hercules.

Shortround6 said:

For the British the only large scale production twin engine aircraft I can think of offhand is the Wellington going from Pegasus engines to Hercules. Not sure how the Merlin Beaufighters rate as Merlins didn't really supply more power than the Hercules.

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Not forgetting Merlin and R-1830 variants. Though not makor variants, several hundred Merlin versions were built and a couple hundred with the R-1830.

I would like to find more details of the Wellington MK II and MK IV. You are certainly correct in mentioning them but I don't think there was a a major change in performance or capability with the Merlin X engine or the P & W R-1830. details on weights would be interesting.
According to one source the tare weight of the MK III with Hercules engines was almost 4000lbs heavier than the 1C with the Pegasus engines which is obviously way more than the difference of the bare weight of the engines.

Like I said, it would be interesting to see where the Merlin and Twin Wasp version landed on the spectrum.

Wellington II
Tare 20,050 lb
Light 22,500 lb
Mean 27,600 lb
Max 32,000 lb

Wellington IV
Tare 20,150 lb
Light 23,200 lb
Mean 27,500 lb
Max 31,600 lb

Mk.II seems to perform better (especially at higher alt) in everything but take off distance.

Having met many WW2 Luftwaffe pilots in my line of work, I asked them about the various Allied fighters they faced and they always rated the P-38 as a dangerous opponent when it had the energy/ airspeed advantage. Once it became a dogfight, then the single engine fighters had a distinct advantage. As expected.They to a man had a great respect for the P-38.

pbehn said:

For much of the war there were huge domains that were ruled by twin fighters, the North Sea the Atlantic and the dark.

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Then there were aircraft carriers.....

swampyankee said:

Then there were aircraft carriers.....

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Yes, but my post said "for much of the war". In Europe the conflict was one sided because the Germans didn't have any. An aircraft carrier group looks formidable and it is, for a carrier group. In an imaginary conflict between all 1944 USA carrier groups and Malta stocked with the best equipment the UK had in 1944 my money would be on Malta because you cant sink it and the damage you can do with single engine planes is limited. Aircraft carriers big and small and escort carriers were best on the open sea, when they come within range of land bases they face an opponent that can sink them but cannot be sunk.

True, true, but their fighters will be able to defeat twins. How would a Me110 fair against even a Wildcat?

swampyankee said:

True, true, but their fighters will be able to defeat twins. How would a Me110 fair against even a Wildcat?

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The point I originally made was about a domain controlled by twins. This is as permanent as the land bases they flew from. The domain controlled by Wildcats (martlet) is within the range of the few carriers in service. The same could be said for the mid Atlantic which for a while was the complete domain of the B24. By 1944 twin engine aircraft in 1944 would monitor your wilcats group, conduct its activities elsewhere and when the time is right attack its supply chain and escorts.

pbehn said:

The point I originally made was about a domain controlled by twins. This is as permanent as the land bases they flew from. The domain controlled by Wildcats (martlet) is within the range of the few carriers in service. The same could be said for the mid Atlantic which for a while was the complete domain of the B24. By 1944 twin engine aircraft in 1944 would monitor your wilcats group, conduct its activities elsewhere and when the time is right attack its supply chain and escorts.

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Theoretically thinking only. If this had happened in 1944, the German twins would have been up against USN Carrier based not Wildcats, but Hellcats and then Corsairs, a serious game changing performance difference here. Just my thoughts. .

And in 1944 the British were getting F6Fs and F4Us, I believe the carrier strikes against the Tirpitz were escorted/supported by F6Fs and F4Us?

However we can get confused by timelines, many times the introduction of a new aircraft (either single or twin) can change the tactical situation for a time. Like 2000hp singles vs twins with 1200-1500hp engines. Introducing twins with 2000hp engines can swing things back.

This makes talking about generalities hard as often you can find specific examples that counter them.

YF12A said:

Theoretically thinking only. If this had happened in 1944, the German twins would have been up against USN Carrier based not Wildcats, but Hellcats and then Corsairs, a serious game changing performance difference here. Just my thoughts. .

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I was discussing purely from a theoretical point of view. Carriers have a problem when operating near land. If the wind blows toward your target you must sail away from it and if it is blowing from your target you must sail towards the land. Staying stationary is an option that leaves you vulnerable and causes heavy landings. When Malta was under siege the British never considered sailing carriers there to "duke it out" but re supplied Malta with Hurricanes and later Spitfires launched from a long way away to land on Malta. In the second world war, with all aircraft being carrier capable and numbers being limited they were multi role and generally suffered from it.

pbehn said:

The point I originally made was about a domain controlled by twins. This is as permanent as the land bases they flew from. The domain controlled by Wildcats (martlet) is within the range of the few carriers in service. The same could be said for the mid Atlantic which for a while was the complete domain of the B24. By 1944 twin engine aircraft in 1944 would monitor your wilcats group, conduct its activities elsewhere and when the time is right attack its supply chain and escorts.

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The domain I think you're referring to is the domain ruled by long-ranged patrol and reconnaissance aircraft, not two-engined fighters; in the WW2 era there were very few twin-engined fighters that could fight on equal terms with contemporary single-engined fighters including contemporary carrier-based fighters. Part of this was because twins will have proportionately larger wetted area than singles, part because they were frequently biased for longer range, part because they tended to have much greater roll inertia and correspondingly reduced instantaneous maneuverability. As an aside, part of the mission of those single-engined carrier fighters is to shoot down recon aircraft.

swampyankee said:

The domain I think you're referring to is the domain ruled by long-ranged patrol and reconnaissance aircraft, not two-engined fighters; in the WW2 era there were very few twin-engined fighters that could fight on equal terms with contemporary single-engined fighters including contemporary carrier-based fighters. Part of this was because twins will have proportionately larger wetted area than singles, part because they were frequently biased for longer range, part because they tended to have much greater roll inertia and correspondingly reduced instantaneous maneuverability. As an aside, part of the mission of those single-engined carrier fighters is to shoot down recon aircraft.

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In my opinion all military planes fight, they just fight in different ways against different things. The Beaufighter and Mosquitos fight against shipping is just as valid as the Bf109s fight against heavy bombers. As was the Ju88 against Sunderlands and Liberators in the mid atlantic.

pbehn said:

In my opinion all military planes fight, they just fight in different ways against different things. The Beaufighter and Mosquitos fight against shipping is just as valid as the Bf109s fight against heavy bombers. As was the Ju88 against Sunderlands and Liberators in the mid atlantic.

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I'm not arguing here -- combat airplanes fight -- this started because I stated that twin-engined fighters would not be able to compete with carrier-based air in the areas where land-based single-engined aircraft would be unable to reach.

Shortround6 said:

And in 1944 the British were getting F6Fs and F4Us, I believe the carrier strikes against the Tirpitz were escorted/supported by F6Fs and F4Us?.

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They were indeed. Operations Tungsten, Mascot and Goodwood all made use of the American fighters operated by the FAA.

Cheers

Steve

Jon Ellison said:

Oop's I mean't Dehaviland Hornet (not F-18!).

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The Hornet (DH) is a great example to use in this discussion. While working on a Whirlwind project I wanted to compare it to its nearest UK equivalent as it used the streamlined Merlin versions that would have been ideal for the WW and came up with some interesting information as I did so. The most relevant here perhaps would be a post war encounter whereby a SeaFury pilot in conversation boasted about how his aircraft could wipe the floor with the Hornet in a dogfight. So they put it to the test and reports say that the result was anything but a slam dunk for the SF. The aircraft seem to have been pretty competitive depending upon the skill of the pilot using the different qualities of their type to its full advantage.

As for the Whirlwind its pilots (certainly while it was current in its first year) felt it was competitive in engaging 109s especially at low level indeed its first engagement was successful against them later ones less so and there are all sorts of arguments in and around this regarding its competitiveness, but sadly as a frozen design even before its first engagement there is no real compelling evidence on which to come to true conclusions. However during the war it was probably the only significant twin aircraft that was specifically designed as a lightweight intercepter in the same way as a Spitfire or ME109 was. The mossie was not though its qualities and potential through experience spawned the Hornet as a true fighter derivative ideal for the direction the fighter was already headed, i.e. heavier, more powerful, longer range over lightweight short range dogfighter. Had the WW been developed or equipped with Merlins as originally planned it would have been a true test between twins and singles of the time but sadly it never happened for reasons other than its innate qualities. So this is always going to be a what if argument in an environment where the goal posts moved considerably from 39 to 45.

Fanciful I know, but later drawing board designs such as the Miles M22 which on paper would have been lethal even to early jets, would I suspect have tilted the balance towards twins in this argument substantially because the type of engagement by the end of the war had become very different with the qualities of an out an out lightweight dogfighting single far less important than the outright power of a twin.