Maneuverability vs Speed

GregP · Jun 2, 2023

Wild_Bill_Kelso said:
Right, we have discussed this before. It's interesting and important. I make the distinction between WEP vs overboost, because WEP settings are usually approved as 'safe' for the engine, based on testing. Of course, that doesn't mean it was 100% safe. Engines broke or even caught fire blew up fairly routinely in military service. They were basically racing engines, very veyr powerful ones at the limits of the technology of the day, and were as temperamental as the engines on a racetrack.

Overboost means the pilot took the boost setting past what was recommended / allowed emergency maximum. You are right that a 1944 WEP setting was not the 1942 official setting. The 1944 setting came from the overboosting routinely being done by P-40 pilots in the Pacific and the Mediterranean. Not sure if it was also done by P-39 pilots, (I assume it was), and I know the P-38 had specific and unique issues. As we know via the famous Allison memo, Allison and the War Department and the units basically worked out what was the 'best practice', though of course if the pilot was fighting, or running, for his life, guidelines may likely go right out the window.

The original maximum boost settings from the early manuals was too low, given the speed and performance of enemy aircraft, and people who stuck to those guidelines often paid with their life. They appear to have gone right past it within weeks or even days of combat in many cases. Pilots from the Australian 75th Sqn in New Guinea described boosting at 70" in their very first air battles with Zeros. In the MTO Theater, also Australian and then some British and South African units were doing this with their P-40D Kittyhawks after about 5-6 weeks.

I believe over time, the maximum boost settings (WEP) were used routinely while the overboost (beyond WEP) ratings were used less often (only in true life or death emergencies), except in cases like with the British recon Mustangs where the unit had carefully worked out how far they could push things in specific conditions.

The big scorch mark and often leaking oil also gave this away I think

And at a bit higher altitude when coming out of a dive, apparently

Seeing as takeoff power was routinely used ... for takeoff, especially when carrying bombs and / or external fuel tanks, I would think the wire would be set at least for 51" or whatever takeoff power was. Otherwise you aren't going to know much about "overboost" / WEP because the wire is already going to be broken before the plane is 100' off the ground .

Engines did NOT break or catch fire frequently. They were and ARE VERY reliable.

I worked the Planes of Fame airshow for 10 years and we flew an average of 50 sorties per day for three days at each airshow. That's 1,500 sorties over 10 years with an average of about 30 WWII aircraft per show. In all that time we had 5 takeoff aborts after engine start. 1 was a flat tire, 1 was a Corsair that couldn't get a wing to unfold (hydraulic valve), 1 was a rough-running R-2800 that was traced to several fouled spark plugs and he aborted at about 50 knots (flew later, after changing the plugs), 1 was an R-1820 that backfired on short final approach and blew out a case gasket (it still taxied in and parked ... pilot error with the mixture), and one was aircraft-related and not a danger to flight ot aircraft, but safe is better than sorry in an airshow warbird.

That's two engine-related failures in 1,500 sorties some 55 - 65 years after these were active military engines. That's 0.13% engine-related issues that happened over 50 years after these were out of service. I'm not saying the military had that performance during wartime, but the engines were VERY reliable. The TBOs were NOT set due to engines that were running badly; they were set so that over 99.5% of all engines being sent it for overhaul could be overhauled and not replaced. That is, the TBO was set so the engine cases could be reused successfully when it came time for overhaul, not for operational issues.

We had zero engine fires. The military had a few, but not many. That's why there are guys with fire extinguishers around every radial at startup. Usually a so-called fire is oil that caught fire due to hot exhaust and it burns out rapidly, usually 3 - 5 seconds, before anyone can even get the extinguisher ready for use. Not always, mind you, but most of the time. I am not working on being around flying warbirds up and close for 18+ years in a row, and I have yet to encounter an engine fire. Not to say they don't happen, just not very often.

Wild_Bill_Kelso · Jun 2, 2023

GregP said:
Engines did NOT break or catch fire frequently. They were and ARE VERY reliable.

I worked the Planes of Fame airshow for 10 years and we flew an average of 50 sorties per day for three days at each airshow. That's 1,500 sorties over 10 years with an average of about 30 WWII aircraft per show. In all that time we had 5 takeoff aborts after engine start. 1 was a flat tire, 1 was a Corsair that couldn't get a wing to unfold (hydraulic valve), 1 was a rough-running R-2800 that was traced to several fouled spark plugs and he aborted at about 50 knots (flew later, after changing the plugs), 1 was an R-1820 that backfired on short final approach and blew out a case gasket (it still taxied in and parked ... pilot error with the mixture), and one was aircraft-related and not a danger to flight ot aircraft, but safe is better than sorry in an airshow warbird.

That's two engine-related failures in 1,500 sorties some 55 - 65 years after these were active military engines. That's 0.13% engine-related issues that happened over 50 years after these were out of service. I'm not saying the military had that performance during wartime, but the engines were VERY reliable. The TBOs were NOT set due to engines that were running badly; they were set so that over 99.5% of all engines being sent it for overhaul could be overhauled and not replaced. That is, the TBO was set so the engine cases could be reused successfully when it came time for overhaul, not for operational issues.

We had zero engine fires. The military had a few, but not many. That's why there are guys with fire extinguishers around every radial at startup. Usually a so-called fire is oil that caught fire due to hot exhaust and it burns out rapidly, usually 3 - 5 seconds, before anyone can even get the extinguisher ready for use. Not always, mind you, but most of the time. I am not working on being around flying warbirds up and close for 18+ years in a row, and I have yet to encounter an engine fire. Not to say they don't happen, just not very often.

Ok, it sounds like you know whereof you speak. But!

I'm going to take a wild guess on some of this so correct me if I'm wrong:

You have pretty much ideal conditions for maintenance - clean, climate controlled buildings out of the elements.
(in WW2, they might not even have overhead cover. Subject to sandstorms, high humidity, torrential rain, snow, baking heat, bone cracking cold etc. etc.)
You have a staff of well educated and / or highly experienced experts who really know the aircraft and engines etc.
(in WW2 some of these planes were brand new and the mechanics were conscripted youngsters barely out of their teens)
You have the benefit of decades of experience and knowledge.
(some WW2 mechanics were experts, but not all by any means, especially in the earlier parts of the war)
You have mostly good parts made to a high standard. In some cases, to a standard that wasn't even available when these were flying in combat.
(in WW2 some parts were not ideal, others had to be salvaged from damaged aircraft etc.)
Same with consumables like fuel, oil, hydraulic fluid etc.
You are also able to keep these consumables clean more easily, due to nice maintenance hangars etc. Not so much sand in the oil.
Your aircraft do not sustain battle damage such as bullet and shell strikes, shrapnel etc.
Your aircraft are also not shooting cannon and machine guns.
Your aircraft are not routinely pushed past the breaking point in terms of high G maneuvers and overboosting etc. (I know you do some in racing)
These aircraft don't routinely fly from high altitude ~ 25-30,000 ft down to Sea Level

The biggest factor I would think would be battle damage, maintenance conditions, and quality of parts / consumables, as well as expertise. Flying very high to very low altitude could also be a significant issue as far as the integrity of seals, lines, reservoirs etc. and the possibility of leaks.

Wild_Bill_Kelso · Jun 2, 2023

Anyway I can tell you that WW2 pilots do describe engines failing and catching on fire before takeoff, during takeoff, and in normal flight. In the Western Desert, if 12 aircraft took off for a mission, it was normal for at least 1 or 2 to have a serious engine or other mechanical problem and have to turn back to base before a shot was fired.

These problems included fires.

GregP · Jun 2, 2023

Never said they didn't have those failures. I said they were not frequent.

Go watch a film of a B-17 wing taking off. 25 - 35 B-17s with 4 engines each and ALL of them usually get airborne without incident ... all 100 - 140 radials. Did they have failures?

Of course. But they weren't "frequent," by any means.

Wild_Bill_Kelso · Jun 2, 2023

Fair enough, and to be sure that is impressive.

But again, are we talking about B-17s in a nicely appointed field in temperate England? Or somewhere in New Guinea, the Solomons, Egypt, Russia, Burma, China, Alaska, etc.

I wonder if you got reliability like that from the B-17s operating in the Pacific or North Africa? Their availability rates weren't that high.

If you like, i can quote some excerpts where fighter pilots and flight leaders mention the routine cases of serious to catastrophic engine failures. As I said before, the rate was often 5-10% or more.

GregP · Jun 2, 2023

Operating from coral runways, I can believe it. Coral screws up everything. Operating in a very dusty environment, I can believe it ... say desert. Dust IS a 4-letter word. Douse it with salt water and all bets are off. Salt water is eating away entire continents. An airplane is trivial by comparison.

Otherwise, it doesn't ring very true. Engines were and are very reliable. Ditto propellers ... unless you scrub the tips in dirt while turning or operate from coral or fail to wash off salt water.

Escuadrilla Azul · Jun 2, 2023

Ovod said:
For what it's worth Wikipedia says:

Kawanishi N1K - Wikipedia

Escuadrilla Azul said:
Sources seems a bit old.

In this book the 343 Ku history is told and claims, IIRC, are balanced against allied loses.

I wil try to found out when arrive home, some hours from now:

Amazon.com

Definitely wasn't 343 Ku (first combat sortie in mid march).

In the HELLCAT vs SHIDEN/SHIDEN-KAI book by Tony Holmes is stated that late in the morning of February 16 1945, the Air Arsenal and Yokosuka Kokutai scrambled a mixed formation of at least eleven fighters (A6Ms, J2Ms and N1K2‑Js) that fought with Hellcats from VF-82 over Atsugi and used dive & zoom tactics developed by tha Air Arsenal over the low flying F6Fs.

Muto (spelled Mutoh also) claimed 4 and VF-82 losed 6 that day. Muto was a China veteran and regarded as a great marksman. He was KIA latter with 343 Ku.

So it seems that a bunch of japanese combat veterans take height advantage over low flying (and probably bound for a ground attack) Hellcats and used D&Z to the full, with the F6Fs pilots trying to beat a hasty retreat to avoid the worst.

The most important thing that time about high speed was to get out of the bad situation ASAP.

Maneuverability seems most irrelevante that time.

Wild_Bill_Kelso · Jun 2, 2023

GregP said:
Operating from coral runways, I can believe it. Coral screws up everything. Operating in a very dusty environment, I can believe it ... say desert. Dust IS a 4-letter word. Douse it with salt water and all bets are off. Salt water is eating away entire continents. An airplane is trivial by comparison.

Otherwise, it doesn't ring very true. Engines were and are very reliable. Ditto propellers ... unless you scrub the tips in dirt while turning or operate from coral or fail to wash off salt water.

Well dust was a major issue in the middle east and on many of the Pacific islands. Coral runways were also common in the Pacific. I'll transcribe a few examples when I get the time.

One weird thing is that they used to clean dust off with petrol at least in some places. Seems a little risky but I admit, I am not a mechanic by any stretch!

GregP · Jun 2, 2023

Petrol works well to clean a number of things on airplanes. Jet fuel and kerosene work great. Was about universal aircraft cleaning fluid in WWII.

Wild_Bill_Kelso · Jun 2, 2023

Figures it was a prosaic kinda thing, I thought it was ... interesting!

Thumpalumpacus · Jun 2, 2023

The other thing is that gasoline is very volatile, especially in a hot climate, meaning that it evaporates very quickly. Just don't smoke while you're using it.

GregP · Jun 3, 2023

GregP said:
Operating from coral runways, I can believe it. Coral screws up everything. Operating in a very dusty environment, I can believe it ... say desert. Dust IS a 4-letter word. Douse it with salt water and all bets are off. Salt water is eating away entire continents. An airplane is trivial by comparison.

Otherwise, it doesn't ring very true. Engines were and are very reliable. Ditto propellers ... unless you scrub the tips in dirt while turning or operate from coral or fail to wash off salt water.

Edit: Maybe not quite so reliable with Curtiss Electric props. They DID require some service to keep the brushes clean.

Reluctant Poster · Jun 4, 2023

GregP said:
Petrol works well to clean a number of things on airplanes. Jet fuel and kerosene work great. Was about universal aircraft cleaning fluid in WWII.

Before the rise of the automobile the valuable product from oil was kerosene . Gasoline was a waste product with limited use as a solvent and cleaner. Most of it was dumped into the nearest creek.

special ed · Jun 4, 2023

The kerosene was developed from the oil seeping from the ground in Pennsylvania and used in lamps for lighting, putting the whale oil industry out of business.

Wild_Bill_Kelso · Jun 4, 2023

Alchemists were making kerosene ('white naphtha') in small quantities back to the 13th Century or earlier. They knew of it (as a byproduct of bitumen) back to Classical times.

Reluctant Poster · Jun 5, 2023

pbehn said:
Nothing flies properly with a bird cage, you need a Malcolm hood for top performance. Seriously, regarding the P-51, I dont think the British could have designed it. It needed a fresh approach from people not steeped in an ongoing war and other design ideas. But then for other reasons the Americans wouldnt have ordered the Mustang/ P-51. It required a huge number of events and coincidences to get into service, and almost "missed the bus" on many occasions.

Ironically you need good visibility to get the maximum performance in combat for any aircraft.

pbehn · Jun 5, 2023

Reluctant Poster said:
Ironically you need good visibility to get the maximum performance in combat for any aircraft.

I know, one of the mysteries of aviation is that the scheduled replacement for the Spitfire, the Typhoon and Tornado came out like this.

yulzari · Jun 6, 2023

pbehn said:
I know, one of the mysteries of aviation is that the scheduled replacement for the Spitfire, the Typhoon and Tornado came out like this.
View attachment 724095

It must be good as it had wind tunnel data to confirm the efficiency of the design.

If only it had data on the efficiency of the wind tunnel……

No, wait. There was relevant data. It was from all the other wind tunnels in the world. But then they were made by foreign johnnies so they don't count and there is nothing wrong with a wind tunnel with 90 degree square corners.

drgondog · Jun 6, 2023

pbehn said:
I know, one of the mysteries of aviation is that the scheduled replacement for the Spitfire, the Typhoon and Tornado came out like this.
View attachment 724095

This example needs more context. Such as time of the picture taken, place in production sequence leading to bubble top conversion, experimental example? I don't personally know enough about this airplane.

drgondog · Jun 6, 2023

NTGray said:
Remember that the Zero, which was considered in 1942 to be an amazing plane that outclassed its "inferior" opponents, did not actually do all that well in the real world. The Zero was always a "one trick pony" that had extraordinary maneuverability, but little else (except range, which didn't matter during actual combat). Even though our American pilots were initially impressed by the Zero's aerobatic capabilities, they did figure out ways to shoot it down, and those ways leaned heavily on teamwork, training, and the Wildcat's superior speed in a dive. Those "inferior" Wildcats actually gave better than they got, and the ratio became more and more in favor of the Wildcat with the passage of time, approaching 6:1 toward the end of the Guadalcanal campaign.

Careful while playing with ratios over Guadalcanal - while Foss had high % A6M in his kill portfolio, most of the aircraft downed by F4F there - were bombers.

Maneuverability vs Speed

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