I am well aware that the Spitfire especially could go faster in a dive, it was one of the fastest ever recorded, I just thought that the test would be horizontal. Not an expert but I thought in the true and indicated airspeeds depend on altitude, and also roll rate changed with altitude?
Which is the better airplane?
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MIflyer
1st Lieutenant
Basic data
XF2A-1 950 HP@SL 277.5 mph at 15,200 ft 3711 lb empty 5017 lb loaded
F2A-1 940 HP@SL 301 mph at 17,000 ft 3785 lb empty 5055 lb loaded (B-239)
XF2A-2 1,200 HP@SL 325 mph at 16,100 ft 4131 lb empty 5409 lb loaded
F2A-2 1200 HP@SL 323 mph at 16,500 ft 4576 lb empty 5492 lb loaded
B-339E 1100 HP@SL 313 mph at 13,500 ft 4479 lb empty 6840 lb loaded
F2A-3 1200 HP@SL 321 mph @ 16,5600 ft 4732 lb empty 6321 lb loaded
Note: F2A-3 normal range 965 sm, B-339E normal range 520 sm
XF2A-1 950 HP@SL 277.5 mph at 15,200 ft 3711 lb empty 5017 lb loaded
F2A-1 940 HP@SL 301 mph at 17,000 ft 3785 lb empty 5055 lb loaded (B-239)
XF2A-2 1,200 HP@SL 325 mph at 16,100 ft 4131 lb empty 5409 lb loaded
F2A-2 1200 HP@SL 323 mph at 16,500 ft 4576 lb empty 5492 lb loaded
B-339E 1100 HP@SL 313 mph at 13,500 ft 4479 lb empty 6840 lb loaded
F2A-3 1200 HP@SL 321 mph @ 16,5600 ft 4732 lb empty 6321 lb loaded
Note: F2A-3 normal range 965 sm, B-339E normal range 520 sm
Attachments
The graphic leaves out the fact the roll rates were tested using only 1/4 aileron.
On the Brewster B-239 and the FiAF vs the VVS
Stalin's purges had a little effect on the skills of the VVS first-line pilots because the victims were higher ranking officers. It might have some effect on the tactics and much effect on the way higher echelons worked because many experienced leaders were shot and others became very careful not to do something too independent. It was better to follow orders to the letter.
In fact in June 1941 there were many VVS pilots with combat experience (China, Spain, Khalkhyn Gol, the Winter War).
What caused the significant loss of the skills of an average VVS fighter pilot later on was the massive losses during and after the Summer of 1941.
And the biplanes FiAF Brewster met were mostly I-153 Tchaikas, the most feared opponent during the Winter War. It was slower than B-239 but climbed slightly better, turned much better and rolled faster. Its extreme manoeuvrability and good power-to-weight ratio made it difficult opponent. Already in 1941 Finns also met of course I-16 but also MiG-3 monoplanes.
Stalin's purges had a little effect on the skills of the VVS first-line pilots because the victims were higher ranking officers. It might have some effect on the tactics and much effect on the way higher echelons worked because many experienced leaders were shot and others became very careful not to do something too independent. It was better to follow orders to the letter.
In fact in June 1941 there were many VVS pilots with combat experience (China, Spain, Khalkhyn Gol, the Winter War).
What caused the significant loss of the skills of an average VVS fighter pilot later on was the massive losses during and after the Summer of 1941.
And the biplanes FiAF Brewster met were mostly I-153 Tchaikas, the most feared opponent during the Winter War. It was slower than B-239 but climbed slightly better, turned much better and rolled faster. Its extreme manoeuvrability and good power-to-weight ratio made it difficult opponent. Already in 1941 Finns also met of course I-16 but also MiG-3 monoplanes.
Fighterguy
Airman
Besides such statistics as roll rate, speed, turn radius, rate of climb, etcetera, one should require some of the "soft" stats. Control and instrument layout, crew comfort and ergonomics, and visibility outside the cockpit, for example also factor in. Also, availability and ease of logistical support and maintenance. Being able to keep-em flying and mission capable can make a difference.
Shortround6
Major General
trouble is, as important as some of those factors are, they are "soft". crew comfort and ergonomics, and visibility outside the cockpit, for example can depend on the size of the pilot/crewman. 5'3" or 6'4". It can depend on the length of the mission, what a pilot can put up with for 1 to 1/1/2 hours vs a 6-8 hour mission.
Control and instrument layout, except for some outrageously bad examples, may not factor into things that much. Many pilots only flying 3-6 different aircraft before going to an operational unit. One might expect a primary trainer to have a different cockpit layout and controls from an advanced trainer (one seldom went backwards) and then an operational aircraft. Few pilots swapped aircraft back and forth. Like a P-47 one day and a P-51 the next and then back to the P-47 the next week.
Standardized cockpits would have been nice but again, most pilots stayed with one type for weeks if not months before switching to a different type of aircraft, some pilots, depending on air force, stayed in the same type (same cockpit) for years. What kind of cockpit fighter "C" had in unit several miles away made no difference to them.
Fighterguy
Airman
Allow me to clarify. I'm referring to individual platforms. I'm fully aware that aircrew don't interchange between aircraft models, outside a unit upgrade (exchanging P-38 for P-51 for example). I'm referring to how easy is the aircraft to operate for the average pilot. In most cases, instrument layout has been fairly standardized. The difference though, say between a Spitfire's control yoke and that of the Me-109, can provide a slight edge in the Spitfire's favor. A bubble canopy provides greater 360 degree visibility than a framed canopy (again, Spitfire vs Me-109), when scanning for potential attackers from the 6 o'clock. A pilot who is provided a simpler, more ergonomic control layout, with room to twist about (not cramped), will have the advantage.
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- #28
MIflyer
1st Lieutenant
When the Aussie Air Force got the F-111C they announced that neither pilots much over 6 ft tall nor ones who smoked would be allowed to fly it. They had too few of them and they cost too much to let people who were not perfect for the airplane fly it.
I wonder about the challenges of operating the engine. On the P-38, P-39, P-40, and Allison Mustang there was not that much the pilot had to do. The single stage single speed superchargers had no controls to fiddle with; it was just throttle, mixture, and prop controls. On the other hand the V-1710's before the P-40M had no automatic manifold pressure limiter; you could blow up the engine just by shoving the throttle in too far at too low and altitude. I recall reading where one P-40E pilot jumped in his airplane when the PI was attacked, shoved the throttle all the way in and desperately tried to build up some speed, get out under the rain of bombs, and gain some altitude. He looked at his manifold pressure gauge wand was horrified; he was only pulling about 10 inches! His engine was shot! But then he realized that the gauge had gone all the way around and passed "zero" again; e was pulling something like 60 inches.
On the later P-38's, after the J model they added a intercooler air control so the pilot could keep the air intake temps to the engine from getting too low, so thatw as one mowe thing for him to do.
On the P-47 the pilot had to adjust the turbo controls so that the "overspeed" warning light was blinking on and off.
On the Merlin Mustang the pilot could operate a momentary switch to kick in the supercharger high speed, for test purposes. For a few they changed it to a regular toggle switch so he could kick in higher boost at lower altitudes.
But in the F4F, FM-1, F6F, F4U and P-61 the pilot had control over engaging the auxillary supercharger and the supercharger speeds. I wonder how much trouble that was?
I wonder about the challenges of operating the engine. On the P-38, P-39, P-40, and Allison Mustang there was not that much the pilot had to do. The single stage single speed superchargers had no controls to fiddle with; it was just throttle, mixture, and prop controls. On the other hand the V-1710's before the P-40M had no automatic manifold pressure limiter; you could blow up the engine just by shoving the throttle in too far at too low and altitude. I recall reading where one P-40E pilot jumped in his airplane when the PI was attacked, shoved the throttle all the way in and desperately tried to build up some speed, get out under the rain of bombs, and gain some altitude. He looked at his manifold pressure gauge wand was horrified; he was only pulling about 10 inches! His engine was shot! But then he realized that the gauge had gone all the way around and passed "zero" again; e was pulling something like 60 inches.
On the later P-38's, after the J model they added a intercooler air control so the pilot could keep the air intake temps to the engine from getting too low, so thatw as one mowe thing for him to do.
On the P-47 the pilot had to adjust the turbo controls so that the "overspeed" warning light was blinking on and off.
On the Merlin Mustang the pilot could operate a momentary switch to kick in the supercharger high speed, for test purposes. For a few they changed it to a regular toggle switch so he could kick in higher boost at lower altitudes.
But in the F4F, FM-1, F6F, F4U and P-61 the pilot had control over engaging the auxillary supercharger and the supercharger speeds. I wonder how much trouble that was?
DarrenW
Staff Sergeant
,
Great points MIflyer. From what's written the Hellcat's pilot manual, it was generally an acquired knowledge. While the basic altitude shift points are given in the manual, other engine control settings (such as the throttle, mixture, and propeller governor adjustments) during these shifts for optimum power were 'learned' skills and sometimes varied according to temperature and even from airplane to airplane. There were other precautions as well, such as a dive should never be attempted in the auxiliary low or high blower speed settings. So yes, it wasn't an easy task to manage the supercharged R-2800, but thankfully proper training and enough time would allow the pilot to become proficient with it's use and after a while I'm sure it became "second nature" to him.
Great points MIflyer. From what's written the Hellcat's pilot manual, it was generally an acquired knowledge. While the basic altitude shift points are given in the manual, other engine control settings (such as the throttle, mixture, and propeller governor adjustments) during these shifts for optimum power were 'learned' skills and sometimes varied according to temperature and even from airplane to airplane. There were other precautions as well, such as a dive should never be attempted in the auxiliary low or high blower speed settings. So yes, it wasn't an easy task to manage the supercharged R-2800, but thankfully proper training and enough time would allow the pilot to become proficient with it's use and after a while I'm sure it became "second nature" to him.
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- Thread starter
- #30
MIflyer
1st Lieutenant
DarrenW
Staff Sergeant
Yes it definitely was a mechanical marvel for it's time. And I totally forgot about the Bearcat's lack of auxiliary blower.
You also mentioned the Thunderbolt's turbocharger controls. Could you elaborate on it's operation, as I do not have access to a P-47 pilot's handbook. I assume that it only had a main-stage supercharger just like the Bearcat, correct?
You also mentioned the Thunderbolt's turbocharger controls. Could you elaborate on it's operation, as I do not have access to a P-47 pilot's handbook. I assume that it only had a main-stage supercharger just like the Bearcat, correct?
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- Thread starter
- #32
MIflyer
1st Lieutenant
See the attached. These manual pages are for the P-47N, and say that in that model there is an automatic regulator that eliminates the need for the overspeed warning light.
Shortround6
Major General
Things changed during the war and some later allied planes got single lever controls for the engine.
Some aircraft had linked controls, I believe in many Spitfires shoving the throttle forward past a certain point also moved the mixture control from lean to rich. Pulling the throttle back may not have leaned out the engine but if you pulling the throttle back that much you probably were out of danger and had time to fool with seperate controls.
Some aircraft had linked controls, I believe in many Spitfires shoving the throttle forward past a certain point also moved the mixture control from lean to rich. Pulling the throttle back may not have leaned out the engine but if you pulling the throttle back that much you probably were out of danger and had time to fool with seperate controls.
- Thread starter
- #34
MIflyer
1st Lieutenant
In the book Flying to the Limit it says that the RAF pilots who flew captured FW-190's and BF-109's said they really liked how well the throttle and engine controls worked.
DarrenW
Staff Sergeant
Thanks for the excerpts. So it looks like the turbo-supercharger unit was basically the auxiliary blower for the P-47. I assume that the supercharger lever ('B' knob) controlled turbine speed, while the main supercharger was controlled by engine rpm, correct?
DarrenW
Staff Sergeant
it's amazing how many different ways engineers sought to give fighter pilots the best combination of engine controls, without making them too cumbersome to operate during stressful combat operations.
Shortround6
Major General
The control may have been linked to the boost.
there was a control box that controlled the waste gate. On early US turbo installations it measured the the pressure in the exhaust system and controlled the waste gate to keep a given pressure, it was thought that this would give an equivalent constant pressure in the intake manifold. Remember that early turbo systems were supposed to deliver sea level pressure to the carb at all altitudes up to around 25,000ft and were not supposed to be used for over boosting the engine.
However, due to water in the exhaust it was found that the 'sensor' often froze during cruise and wouldn't operate properly when the throttle was opened.
ANd with the supply of better fuel (and water injection) it was possible to over boost the engine without wrecking it. A new "control" was adopted that measured the pressure either in the intake manifold or right before the carb (I don'r know which) and then used that sensor input to control the waste gate soe the turbine would spin at whatever was needed to maintain the desired pressure on the intake side.
The pilot doesn't care how fast the turbine is spinning, and in fact doesn't need to know (except if it is going into a danger zone), what he is interested in is how pressure is in the intake manifold.
For example an early P-47 could make 52in of MAP at 5000ft with the turbine spinning 6,800rpm. at 15,000ft 11,800rpm gave 51in map and at 27,800ft 18,500rpm (max) gave 52in map. Set a control so full throttle gave 52in and forget about the rpm.
there was a control box that controlled the waste gate. On early US turbo installations it measured the the pressure in the exhaust system and controlled the waste gate to keep a given pressure, it was thought that this would give an equivalent constant pressure in the intake manifold. Remember that early turbo systems were supposed to deliver sea level pressure to the carb at all altitudes up to around 25,000ft and were not supposed to be used for over boosting the engine.
However, due to water in the exhaust it was found that the 'sensor' often froze during cruise and wouldn't operate properly when the throttle was opened.
ANd with the supply of better fuel (and water injection) it was possible to over boost the engine without wrecking it. A new "control" was adopted that measured the pressure either in the intake manifold or right before the carb (I don'r know which) and then used that sensor input to control the waste gate soe the turbine would spin at whatever was needed to maintain the desired pressure on the intake side.
The pilot doesn't care how fast the turbine is spinning, and in fact doesn't need to know (except if it is going into a danger zone), what he is interested in is how pressure is in the intake manifold.
For example an early P-47 could make 52in of MAP at 5000ft with the turbine spinning 6,800rpm. at 15,000ft 11,800rpm gave 51in map and at 27,800ft 18,500rpm (max) gave 52in map. Set a control so full throttle gave 52in and forget about the rpm.
wuzak
Captain
rpm was, however, the limiting factor on how much boost the turbo could deliver. After a certain rpm the turbine was more likely to fly apart.
Oh, the turbos supplied just above standard sea level pressure at the compressor outlet. That was enough to account for any pressure loss in the ducting and intercoolers, so that the engine see the sea level air pressure.
I don't believe that turbos were used for actually over-boosting the engine.
Oh, the turbos supplied just above standard sea level pressure at the compressor outlet. That was enough to account for any pressure loss in the ducting and intercoolers, so that the engine see the sea level air pressure.
I don't believe that turbos were used for actually over-boosting the engine.
Shortround6
Major General
Not until you got to WEP settings on the P-47, subject to the max rpm limit on the turbine. I would also note that the when climbing the turbine was spinning faster than when flying at high speed in level flight at the same altitudes. It was compensating for the lower ram pressure in the inlet ducts. Something you don't want your pilots trying to figure out when people are shooting at them 
swampyankee
Chief Master Sergeant
- 4,020
- Jun 25, 2013
...but it seems that the USN and USAAF test pilots who flew captured German aircraft did not think that highly of the German's engine control system. Possibly part of this is the sort of snobbery that says Real Drivers use manual transmissions. We know, of course, that Real Drivers must be using crash boxes, not that wimpy synchromesh.
