FLYBOYJ
"THE GREAT GAZOO"
Not nitpicking but you did have Composite Groups in the AAF during WW2 where several different types of aircraft were operated at the squadron level within the group.
XP-39 and the Claims
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Not nitpicking but you did have Composite Groups in the AAF during WW2 where several different types of aircraft were operated at the squadron level within the group.
drgondog
Major
Very True Joe - that said composite operations were almost always a.) very early in the war on places like Guadalcanal where they fought with what they had, r b.) during transition - say from P-47s or P-38s to Mustangs. Mid war in CBI and Pacific, there were still mixed P-39/P-40 and P-40/P-38 composite groups with mixed squadrons. Logistics and spares and 'interchangeability of pilot and parts' nightmares.
drgondog
Major
As I read through this the one over riding thought about the XP-39 is that it was not a very good fighter as built. Kelsey wrote the specs but he was very disappointed in the performance and room for growth into a viable high altitude capable Pursuit aircraft. It was "the Small Solution' compared to the XP-38. It was always cursed with marginal stability, short range and crappy altitude performance (Allison issue, however).
Bell just never did develop either experimental or production aircraft considered better than average (except by 1943 VVS standards) - nobody even claims that either the X-1 or X-1A were 'great'. That changed with Bell Helicopter due largely to Bart Kelley post WWII.
Bell just never did develop either experimental or production aircraft considered better than average (except by 1943 VVS standards) - nobody even claims that either the X-1 or X-1A were 'great'. That changed with Bell Helicopter due largely to Bart Kelley post WWII.
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- #44
GregP
Major
Hi guys,
I'm sure the composite groups were operated but, as stated above, not for long periods. When transitioning types, there is almost always a small overlap. But they wouldn't want the overlap to last for longer than necessary unless there was a specific reason for retaining the old type. I'm sure they might retain a different type as a squadron hack or some other reason. The U.S.A. used several German and Japanese types as squadron hacks or the "commander's plane," including the A6M5 Model 52 Zero that the Planes of Fame now flies. It was a commander's plane for some time on the west coast after the war, but they did that during the war, too. Some U.S. and British units operated Seibel Si.204s during the war when they became available as Luftwaffe fields were overrun. I'd bet some might have wanted to operate enemy fighters, but it would be too easy to get shot down by friendly fire if you were in an armed aircraft and the war was still in full swing, friendly markings notwithstanding.
I'm really not trying to make this into a life story of the Bf 109E or F timeline. Just saying that combat aircraft have a lifespan, and they aren't usually retired until that life span is used up or some other operational reason takes an older aircraft out of service. And ... I did say usually. There are exceptions to almost any rule, even when we don't really want exceptions. I'd think the E's could have been retired by the end of 1942, but probably not ALL of them. We have had several speakers and visitors at the Planes of Fame who said they flew P-39s into late-war, but I'm sorry to say I don't recall the units involved. It didn't seem important at the time ...
I'm sure the composite groups were operated but, as stated above, not for long periods. When transitioning types, there is almost always a small overlap. But they wouldn't want the overlap to last for longer than necessary unless there was a specific reason for retaining the old type. I'm sure they might retain a different type as a squadron hack or some other reason. The U.S.A. used several German and Japanese types as squadron hacks or the "commander's plane," including the A6M5 Model 52 Zero that the Planes of Fame now flies. It was a commander's plane for some time on the west coast after the war, but they did that during the war, too. Some U.S. and British units operated Seibel Si.204s during the war when they became available as Luftwaffe fields were overrun. I'd bet some might have wanted to operate enemy fighters, but it would be too easy to get shot down by friendly fire if you were in an armed aircraft and the war was still in full swing, friendly markings notwithstanding.
I'm really not trying to make this into a life story of the Bf 109E or F timeline. Just saying that combat aircraft have a lifespan, and they aren't usually retired until that life span is used up or some other operational reason takes an older aircraft out of service. And ... I did say usually. There are exceptions to almost any rule, even when we don't really want exceptions. I'd think the E's could have been retired by the end of 1942, but probably not ALL of them. We have had several speakers and visitors at the Planes of Fame who said they flew P-39s into late-war, but I'm sorry to say I don't recall the units involved. It didn't seem important at the time ...
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FLYBOYJ
"THE GREAT GAZOO"
Greg - composite groups were operated in one form or another throughout the war. I believe there were 8 or 9 of them, the most famous was the 509th Composite group, operated Silverplate B-29s and C-54s. The 342nd Composite Group operated for over 2 years and operated at least 4 different types of aircraft. 342nd Composite Group (USAAF). Composite groups operated in the post war and I believe there were a few operated during the Korean War.
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- #46
GregP
Major
Hi,
So, that seems like a deliberate decision to operate a composite group for a specific reason, not an across-the-board haphazard mix of aircraft. I'm sure heavy bombers take many heavy spare parts and having some tramspoprts makes keeping everything running a LOT easier than waiting for somebody else to fly them in.
When I was in the Air Force at Ellsworth in South Dakota, we had a B-52 wing, but we also operated KC-135s and had two semi-permanent T-33s. The B-52 and KC-135 mix makes good sense, and the T-33s were not really often-used, but enough to see them every once in a while.
So, that seems like a deliberate decision to operate a composite group for a specific reason, not an across-the-board haphazard mix of aircraft. I'm sure heavy bombers take many heavy spare parts and having some tramspoprts makes keeping everything running a LOT easier than waiting for somebody else to fly them in.
When I was in the Air Force at Ellsworth in South Dakota, we had a B-52 wing, but we also operated KC-135s and had two semi-permanent T-33s. The B-52 and KC-135 mix makes good sense, and the T-33s were not really often-used, but enough to see them every once in a while.
FLYBOYJ
"THE GREAT GAZOO"
Exactly, but I think some of the Composite units in WW2 existed more out of operational necessity rather than a strategic plan. In the case of the 509th, the supporting C-54s made perfect sense considering what the Group's primary mission was.
Shortround6
Major General
Some of this depends on the theater and the time. In the SW Pacific you were going to get composite groups/wings because you didn't have enough of any type of aircraft.
Two 3 squadron groups each with mixed aircraft or 3-5 understrength groups each with one-two squadrons of identical aircraft?
This was pretty much the situation in NA after Torch with composite wings, not enough groups with identical aircraft to form a wing unless it was a two group wing.
How low you can go depends on the aircraft (and personnel) as trying to operate at squadron level with different types of aircraft (P-40s and P-38s) isn't going to work well in the air, maintenance and supply being a whole different tissue. However certain models of different aircraft are somewhat interchangeable. P-40Ks and Ms? Or P-40Es and Ks ? certain P-39s or even some P-38s could be plugged into a squadron without much disruption. Certain planes could not, P-40F&Ls not only have to be kept separate form other P-40s for maintenance reasons but trying to fly a mixed squadron above 15,000ft would be horror show.
Same with th e109s, you might be able to mix Fs & Gs at certain times but Es and Fs are not going to work in the same squadron, their flight characteristics are too different, A fighter group might very well have several squadrons of FGs and one of Es for a period of time however.
Two 3 squadron groups each with mixed aircraft or 3-5 understrength groups each with one-two squadrons of identical aircraft?
This was pretty much the situation in NA after Torch with composite wings, not enough groups with identical aircraft to form a wing unless it was a two group wing.
How low you can go depends on the aircraft (and personnel) as trying to operate at squadron level with different types of aircraft (P-40s and P-38s) isn't going to work well in the air, maintenance and supply being a whole different tissue. However certain models of different aircraft are somewhat interchangeable. P-40Ks and Ms? Or P-40Es and Ks ? certain P-39s or even some P-38s could be plugged into a squadron without much disruption. Certain planes could not, P-40F&Ls not only have to be kept separate form other P-40s for maintenance reasons but trying to fly a mixed squadron above 15,000ft would be horror show.
Same with th e109s, you might be able to mix Fs & Gs at certain times but Es and Fs are not going to work in the same squadron, their flight characteristics are too different, A fighter group might very well have several squadrons of FGs and one of Es for a period of time however.
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- #49
GregP
Major
I'm not too sure about the mixed operation being difficult. Here is a clip of the Planes of Fame Airshow in 2012 with two P-51s (Merlin variety) and our P-38. They didn't seem to have any trouble. Two four-bladed Merlins and two three-bladed Allisons together. Of course, they weren't in a combat situation, either. But Steve Hinton (in the P-38) wasn't babying the Allisons.
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Greg,
What's the difference between babying the motors and not babying them? I'm assuming he flew at the higher of the speeds required for over the top maneuvers while still leaving his wingmen a little something power wise to stay in formation.
Cheers,
Biff
wuzak
Captain
In WW2 the combination wouldn't work so well as the cruise conditions would not be the same for both aircraft.
One would be at less than optimum performance.
One would be at less than optimum performance.
Shortround6
Major General
At a Modern airshow the Merlins are going to be in low gear. (unless your air show is several thousand feet higher than Denver), Likewise the P-38s turbo (if the airshow planes even have them, yours may, some do not.) are going to be idling or near idle. The show has been carefully choreographed and practiced so the pilots know about what throttle settings to use to maintain their formation, On a given day they may need to make minor adjustments. Part of what separates those pilots from the also rans and wannabees.
But airshows at low altitude don't tell us what the planes were going to be doing at 20, 000ft and up or how different planes with different speeds, climb performance, dive speeds and turning radius are going stay together with out the whole formation having to conform to worst parts of each different types flight envelope.
But airshows at low altitude don't tell us what the planes were going to be doing at 20, 000ft and up or how different planes with different speeds, climb performance, dive speeds and turning radius are going stay together with out the whole formation having to conform to worst parts of each different types flight envelope.
I'm skeptical about the 390 mph claim. As others have mentioned, there were aerodynamic and engine installation issues. Moreover, in this time period it was quite common for manufacturers (and governments) to exaggerate performance claims. Also, many claims were based on calculations. Thee were quite a few experimental planes that never came anywhere close to the calculated or specified performance figures. The British were very disappointed with the P-39s that they ordered - I recall reading that Bell eventually admitted their performance figures were obtained with a stripped machine.
It would be SO easy to position your static ports in spots that are low pressure areas at max speed AOA to gain optimistic airspeed readings. While this wouldn't survive rigorous testing (NACA), it could be used to favourably impress potential buyers evaluation pilots. Just the sort of stunt Larry Bell would be attracted to.
Cheers,
Wes
I was one of the participants in the 1970s P-39 tumbling study. And yes it was totally an unofficial and unfunded test. But now everyone involved is either retired or passed on, so no one can get in trouble, but it can be good lesson on how sometimes historic research gets done. At the time I was an aerodynamics engineer at Beech Aircraft involved in new aircraft development and as part of my job I did both flight testing and wind tunnel testing including many spin tunnel tests at Langley. I studied aviation history both as a hobby and to gain knowledge and data for my vocation of engineering. A friend of mine, who was also an aeronautical engineer and history buff, had been doing research on the P-39 stories of tumbling. He had gone thru the old Wright Field reports and noted that they had seen no tendency of the aircraft to tumble, but he also noted that the flight testing was all done with an equivalent full mass of ammunition in the nose and full fuel. He had interviewed several P-39 combat veterans and they had indicated to him that the tumbling occurred on the return from combat missions when the ammunition had been expended and fuel burned off. He asked me if I had at looked at the NACA P-39 spin tunnel test data? I told him yes, but only from the point of view of the effect of the door opening and of the pilot escape path. But I also informed him I had a spin tunnel test to do at NASA Langley in a few weeks and would ask see the P-39 test data while I was there. My NASA friends pulled the P-39 test file for me and the NACA spin tunnel test had been done at a request from the AAF which called out the test requirements. The AAF had only requested testing at full gross weight and that was all that was done. There was no sign of tumbling seen. Now one has to remember that in WWII the Langley tunnels were running 7 days a week, three shifts a day, so there was little time was for exploring outside the formal test request. During a coffee break in the spin tunnel conference room, I brought up the P-39 tumbling. The NASA engineers got interested and also read the file. Now in the 1970's, the offices, hallways, and conference room in the spin tunnel building all had old spin tunnel models hanging from the ceilings. Now it just so happened one of the models hanging in the conference room was the P-39. Also Jim Bowman, head of the spin tunnel at that time was in on the coffee break and mentioned that in WWII he had been an apprentice in the model shop where the P-39 model was constructed. Well as you probably know engineers and wind tunnel technicians are nothing but over aged little boys, thus a plan was formed to refurbish the P-39 model and test it in those other flight conditions. Of course this was all done on lunch hours and coffee breaks! A few check points were made at the gross weight loadings which repeated the original WWII tests. The model was then reballasted to simulate no nose ammunition and low fuel and retested. And with this loading the P-39 model would sometimes tumble.
Excellent information, thanks for posting!
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GregP
Major
Hi Biff,
By "not babying the Allisons," I mean Steve was sometimes pulling 55"+ MAP. Not always, of course, but I'm assuming when they went vertical on the way up from less-than-high airspeed. The P-38 will outclimb the P-51 at lower altitudes, but not likely from low-but-identical airspeeds. I rather doubt the P-51's were babying their Merlins, either when looping from airshow airspeeds. Neither was either type using even full military power in the airshow clip. After all, they weren't exactly flying with 145 performance number fuel. I doubt if anyone in the formation was pulling more than about 1,000 - 1,100 hp.
As for the comment about what it doesn't show (not yours, Biff), what it clearly tells me is the dissimilar aircraft have no problems flying formation. Our fighters cruise to airshows and other public displays together routinely in formation, and they don't have any trouble. We have even had a P-47, P-38, and P-51 information with an F-22, and THEY didn't have any trouble with it, either.
In fact, I have never heard any of our pilots, speakers, or visitors say they had any trouble flying in formation with another aircraft type. Not sure where the notion they would have trouble staying in formation with dissimilar aircraft would even come from.
I'm sure they wouldn't do it for extended periods unless there was a reason to do so, but the capability is certainly there. Liquid-cooled inline fighters would probably have trouble flying for extended periods at 185 mph (plug fouling), but the radials would have little difficulty cruising at 250 - 280 mph except for the extra fuel consumption. They certainly have the ability to cruise with one another for some time, should the need arise, regardless of altitude, unless you happen to be right at the altitude where a supercharger in one of the birds changes gears automatically.
I'd place a bet that Biff flew formation in an F-15 with something other than another F-15 at some point.
Mal H, THANK YOU for posting!
By "not babying the Allisons," I mean Steve was sometimes pulling 55"+ MAP. Not always, of course, but I'm assuming when they went vertical on the way up from less-than-high airspeed. The P-38 will outclimb the P-51 at lower altitudes, but not likely from low-but-identical airspeeds. I rather doubt the P-51's were babying their Merlins, either when looping from airshow airspeeds. Neither was either type using even full military power in the airshow clip. After all, they weren't exactly flying with 145 performance number fuel. I doubt if anyone in the formation was pulling more than about 1,000 - 1,100 hp.
As for the comment about what it doesn't show (not yours, Biff), what it clearly tells me is the dissimilar aircraft have no problems flying formation. Our fighters cruise to airshows and other public displays together routinely in formation, and they don't have any trouble. We have even had a P-47, P-38, and P-51 information with an F-22, and THEY didn't have any trouble with it, either.
In fact, I have never heard any of our pilots, speakers, or visitors say they had any trouble flying in formation with another aircraft type. Not sure where the notion they would have trouble staying in formation with dissimilar aircraft would even come from.
I'm sure they wouldn't do it for extended periods unless there was a reason to do so, but the capability is certainly there. Liquid-cooled inline fighters would probably have trouble flying for extended periods at 185 mph (plug fouling), but the radials would have little difficulty cruising at 250 - 280 mph except for the extra fuel consumption. They certainly have the ability to cruise with one another for some time, should the need arise, regardless of altitude, unless you happen to be right at the altitude where a supercharger in one of the birds changes gears automatically.
I'd place a bet that Biff flew formation in an F-15 with something other than another F-15 at some point.
Mal H, THANK YOU for posting!
wuzak
Captain
Greg, it's all well and good in an airshow setting.
There is a video on the web showing a Sopwith Pup (or Camel, can't recall exactly) flying in formation with a Spitfire. The Sopwith was flying near its maximum speed and the Spitfire was just above stall.
In the WW2 context, the USAAF would often escort their PR Mosquitoes (F-8/PR.XVI) with P-51s (B or D). The range that the missions could take was compromised because the speed at which the Mosquito and the P-51 could achieve that range was quite a bit different.
By speeding up the P-51s and slowing down the Mosquito a compromise was achieved, but the range of the mission was reduced.
And both those aircraft used 2 stage Merlins, though their best altitude range was different, the Mosquito's 70 series engines having a higher FTH than the P-51's V-1650-7s (Merlin 65/66).
wuzak
Captain
Also why escort missions in the ETO were flown in relays.
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- #60
GregP
Major
Wuzak,
While the normal cruise of a P-51 was about 275 mph, a P-51 didn't have to speed up to cruise with a Mosquito. Mostly the 275 mph cruise speed of the P-51 was to allow it to zig-zag above the bombers to it could stay with them. A P-51D/K had a range of 1100 miles at a speed of 395 mph at 2400 rpm according to the 1944 pilot's manual charts from this forum. Of course, that was not the optimum range for the P-51D/K, but it COULD do it. The 275 mph was the best bomber escort cruise. Heck, it can go 1,500 miles at 370 mph at 2,500 rpm with 269 gallons of fuel on board.
P-51 Cruise Speed = 395 mph TAS
Perhaps I am misreading the manual.
The typical Mosquito wasn't going to do that. Normal cruise was about 295 mph and could go to 325 mph and later 360 mph or so. Yes, it could go faster, but not at cruise speed. Anything over 340 mph was getting into shorter ranges unless you had a specific type, like maybe a 1945 NF. Mk 30. It COULD cruise at 364 mph at 27,500 ft, but max speed was 397 mph at best altitude and the range at 360 mph wasn't all that great. There really weren't all that many Mosquitos that could hit much more than low 400 mph.
The F Mk. II could hit 358 mph. The NF Mk. XV could hit 408 mph or so. The B Mk. IX could hit right at 405 mph. The FB Mk. VI could hit 368 mph or so. The IV could hit 367 - 380 mph depending on the exhaust stub. The PR Mk. XVI could hit 401 mph. These are all maximum speeds in FS gear and optimum altitudes. Any MS gear speed was 15 - 20 mph slower. Yes, it was a fast, amazing airplane, particularly when cruising into hostile airspace, but not faster than a P-51 if the P-51 wanted to fly that fast.
I'll give you this, the Mosquito at optimal cruise was faster than a P-51 at best range cruise. But unless the mission was farther than Berlin and back, the P-51 had plenty of speed and range to stay with a Mosquito. Of course, there wasn't as much room in the P-51 cockpit and the P-51 engine-out performance was nowhere NEAR the Mosquito's.
While the normal cruise of a P-51 was about 275 mph, a P-51 didn't have to speed up to cruise with a Mosquito. Mostly the 275 mph cruise speed of the P-51 was to allow it to zig-zag above the bombers to it could stay with them. A P-51D/K had a range of 1100 miles at a speed of 395 mph at 2400 rpm according to the 1944 pilot's manual charts from this forum. Of course, that was not the optimum range for the P-51D/K, but it COULD do it. The 275 mph was the best bomber escort cruise. Heck, it can go 1,500 miles at 370 mph at 2,500 rpm with 269 gallons of fuel on board.
P-51 Cruise Speed = 395 mph TAS
Perhaps I am misreading the manual.
The typical Mosquito wasn't going to do that. Normal cruise was about 295 mph and could go to 325 mph and later 360 mph or so. Yes, it could go faster, but not at cruise speed. Anything over 340 mph was getting into shorter ranges unless you had a specific type, like maybe a 1945 NF. Mk 30. It COULD cruise at 364 mph at 27,500 ft, but max speed was 397 mph at best altitude and the range at 360 mph wasn't all that great. There really weren't all that many Mosquitos that could hit much more than low 400 mph.
The F Mk. II could hit 358 mph. The NF Mk. XV could hit 408 mph or so. The B Mk. IX could hit right at 405 mph. The FB Mk. VI could hit 368 mph or so. The IV could hit 367 - 380 mph depending on the exhaust stub. The PR Mk. XVI could hit 401 mph. These are all maximum speeds in FS gear and optimum altitudes. Any MS gear speed was 15 - 20 mph slower. Yes, it was a fast, amazing airplane, particularly when cruising into hostile airspace, but not faster than a P-51 if the P-51 wanted to fly that fast.
I'll give you this, the Mosquito at optimal cruise was faster than a P-51 at best range cruise. But unless the mission was farther than Berlin and back, the P-51 had plenty of speed and range to stay with a Mosquito. Of course, there wasn't as much room in the P-51 cockpit and the P-51 engine-out performance was nowhere NEAR the Mosquito's.
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