Kawasaki Ki-100

[Vincenzo]

What japanese docs talking of trouble with boost?
For british trial is not only a boost difference there is a difference also in rpm (british trial 2900 rpm 250 mm Hg, engine specs 3000 rpm 350 mm Hg (the boost can up until 500 for take off, idk also if for wep or injection)

[JoeB]

Originally Posted by Vincenzo

What japanese docs talking of trouble with boost?
For british trial is not only a boost difference there is a difference also in rpm (british trial 2900 rpm 250 mm Hg, engine specs 3000 rpm 350 mm Hg (the boost can up until 500 for take off, idk also if for wep or injection)

It's not 'trouble' it's just difference. The Japanese had no such thing as WEP, for example. Engine specs according to who? I don't know the exact specs but it's a fact the Japanese official best speed for that plane was less than 400. I mean that's the whole discrepancy we're discussing. If the Japanese had posted an official speed equal to the highest in Western trials or estimates, we wouldn't be discussing it right? Aren't you missing something basic here, or am I?

Joe

[Vincenzo]

Originally Posted by JoeB

It's not 'trouble' it's just difference. The Japanese had no such thing as WEP, for example. Engine specs according to who? I don't know the exact specs but it's a fact the Japanese official best speed for that plane was less than 400. I mean that's the whole discrepancy we're discussing. If the Japanese had posted an official speed equal to the highest in Western trials or estimates, we wouldn't be discussing it right? Aren't you missing something basic here, or am I?

Joe

nakajima book.
it's knew japanese data was for plane with homare-11 engine. japanese have not wep terminology sure, all other don't use wep word, but like climb and combat setting for british or combat and take off setting for germans.

[Shortround6]

In some cases the American WEP was just, WAR ENERGENCY POWER. it was not to be used for take off, or climb or for ANY REASON out side of a combat zone. Any use of combat power was to be noted in the log book as more frequint maintainece would be required after a certain amount of time at WEP. In many cases small wire "tell-tales" were place across the throttles that had to be broken in order use the WEP settings.
Other countries may or may not have had similar restrictions on max power settings but if they didn't then the power settings are not strictly comparable.

[vanir]

American engine settings aren't strictly comparable to European or Asian anyway. Theirs were NACA developed during the thirties for the purpose of increasing the normal range of combat aircraft. The normal cruise setting for American fighters is the economy setting for European types, the WEP is often not even listed in operational guidelines and there is a separate 5-10 minute take off setting (WEP is a 5min setting). Climb and combat is still the 30 min setting, but max continuous is also the cruise setting in Europe, whilst in the US it is stated in operational guidelines this setting will not return the listed normal cruise range.
Effectively it bumps the normal cruise range of US fighters on paper, though its purpose was to culture pilots to use lower cruise settings during normal flight. The effect is that a European pilot will get much less range out of an American fighter if he flies it like a European fighter (which may be more appropriate in a European combat environment).
American WEP settings are also a bit of hack and slash. For the F-series Allison it was given by the company as 52" and later increased to 56" although 60" was unofficially sanctioned and recalibrations and engine overspeeding were performed in the field "for extended periods"

Therefore for engine comparisons the International Rating became the standard at this time rather than maximum listed output, which varied by doctrine as well as engine type. It is the 30 minute setting, regardless of where the engine was made and how many take off and WEP settings and grades it has.
For warbirds there is a mixture of maximum claimed outputs and International ratings given for various aircraft, which does rather confuse things tremendously.

For the P-40 series for example, the International rating is invariably given in warbird publication. Actual take off performance is more like 1350hp and up with a WEP of 1550hp and up. Totally changes the perspective of this type's low altitude performance (very, very tough under 10K ft in any role).

For the Spitfire you'll have maximum take-off/WEP (+18lbs or 66"Hg for 5-10min, Merlin XX onwards) ratings given at optimal altitude (about 3100ft).

So two aircraft which perform very similarly under 5000ft are stuck with published figures of ca.1050hp and 1550hp respectively for comparison. No wonder everybody underrates the P-40 and overrates the Spit.

Happy to be corrected on any points, I'm not that much of an expert.

[paradoxguy]

Originally Posted by vanir

Interestingly flight testing of the Fw-190D returned nowhere near the level of admiration that it received from Luftwaffe pilots. It was stated by American test pilots as pretty rough particularly in terms of overall finish, with heavy handling, but considering the circumstances again, was certainly competitive with late war Allied types and that much was impressive at least. IIRC the overall impressions were of a backyard hack with surprising performance for a backyard hack, where the test pilots had expected something far more refined.

Everybody who few a Ta-152 was pretty impressed though, except the Focke Wulf test pilots who found it fell short of calculated expectations at extreme altitude, plus any aircraft of this era experienced a wide variety of technical difficulties operating at such altitudes in the first place. But very, very strong from 7000 metres to excess of 10500 metres, and not altogether a slouch at lower altitudes either.

Definitely I also have a distaste for presenting calculated figures as any reflection of actual flying characteristics whatsoever. The opposite should be strenuated.

Thanks to everyone who contributed to this thread, it's been educational about the Ki-100 specifically and flight testing in general.

Vanir-I was intrigued by your comments about the impressions of American test pilots of the Fw 190D and how the airplane seemed much more crude than expected. I have also read that American fighter pilots who were able to fly the Dora were not highly impressed with it and generally felt the P-51 and P-47 outperformed it. As you stated, these opinions certainly stands in contrast to expressed opinions of many Luftwaffe fighter pilots of the Fw 190D-9. Their opinions seem to contrast sharply also with Eric Brown's opinion of the Fw 190D-9 in his article "Flying the Fw 190: Kurt Tank's Butcher Bird" (October 2000, Flight Journal). Below is his concluding opinion of the Dora from the Flight Journal article; he even prefaces the Fw 190D-9 section with "The fabulous D arias":

The Dora 9 was one of the finest piston-engine fighters I have ever flown; it ranks among my top five with the Spitfire XIV, the Grumman Bearcat, the Hawker Sea Fury and the North American P-51D Mustang IV. It had all the handling qualities of the A-series, and its performance was outstanding. Top speed was 426mph (685km/h) at 21,500 feet (6,500m) and 357mph (574km/h) at sea level. Initial rate of climb was 3,500 feet per minute, and its service ceiling was 40,000 feet. With an MW-50 water/methanol injection, it reached a speed of 453mph (730km/h). Seven hundred Doras were produced, but a shortage of pilots and aviation fuel during this period (the fall of 1944) meant that the Dora's full military potential was never utilized.

I find interesting also that Brown's cited top speed (with MW-50 boost) of 453 mph and service ceiling of 40,000 feet are significantly higher than many sources on the Dora. In fact, I recall reading that some Fw 190D-9's were delivered without MW-50 boost and their top speeds were no more than 360 mph, perhaps suggesting that the commonly cited top speed of 426 mph was achieved with MW-50 boost. Brown doesn't state whether he actually measured these performance figures or is quoting them from another source, but since he was a test pilot flying the Dora, I wonder if this would suggest he actually measured or helped measure these parameters. Certainly if he derived these figures personally, they suggest the Fw 190D-9 had a notably higher performance than commonly thought.

Anyway, just some more proverbial food for thought. I'm also in the chorus of those who agree with Vanir that calculated performance figures should not be taken as any indication of a plane's true characteristics.

[20317]

i dont understand why absolutes are always referred to when describing a planes value.

i understand the Ki-100 was well armed, agile and had a reasonable turn of speed.

when i see max performance figures quoted, i always wonder how many combats occurred at those top speeds..... and how much the less tangible qualities of the fighter resulted in its reputation.

[paradoxguy]

Originally Posted by 20317

i dont understand why absolutes are always referred to when describing a planes value.

i understand the Ki-100 was well armed, agile and had a reasonable turn of speed.

when i see max performance figures quoted, i always wonder how many combats occurred at those top speeds..... and how much the less tangible qualities of the fighter resulted in its reputation.

You touched on the central themes of my original question that started this thread. The published performance parameters of the Ki-100 are not very impressive, such as speed and combat ceiling, but it was well-regarded by its pilots, so I was wondering what qualities made it so, such as maneuverability, ease of flying (especially with the lower average of training and proficiency by late-war pilots), protection, etc. In fact, some sources indicate it was held in higher regard by its pilots than the Ki-84 Hayate, whose published performance parameters significantly exceed the Ki-100 (speed, climb) and whose renowned butterfly flaps supposedly made it very agile. As you pointed out, if the Ki-100's reputation is justified, I suspect its less tangible qualities are key.

[vanir]

Originally Posted by paradoxguy

Thanks to everyone who contributed to this thread, it's been educational about the Ki-100 specifically and flight testing in general.

Vanir-I was intrigued by your comments about the impressions of American test pilots of the Fw 190D and how the airplane seemed much more crude than expected. I have also read that American fighter pilots who were able to fly the Dora were not highly impressed with it and generally felt the P-51 and P-47 outperformed it. As you stated, these opinions certainly stands in contrast to expressed opinions of many Luftwaffe fighter pilots of the Fw 190D-9. Their opinions seem to contrast sharply also with Eric Brown's opinion of the Fw 190D-9 in his article "Flying the Fw 190: Kurt Tank's Butcher Bird" (October 2000, Flight Journal). Below is his concluding opinion of the Dora from the Flight Journal article; he even prefaces the Fw 190D-9 section with "The fabulous D arias":



I find interesting also that Brown's cited top speed (with MW-50 boost) of 453 mph and service ceiling of 40,000 feet are significantly higher than many sources on the Dora. In fact, I recall reading that some Fw 190D-9's were delivered without MW-50 boost and their top speeds were no more than 360 mph, perhaps suggesting that the commonly cited top speed of 426 mph was achieved with MW-50 boost. Brown doesn't state whether he actually measured these performance figures or is quoting them from another source, but since he was a test pilot flying the Dora, I wonder if this would suggest he actually measured or helped measure these parameters. Certainly if he derived these figures personally, they suggest the Fw 190D-9 had a notably higher performance than commonly thought.

Anyway, just some more proverbial food for thought. I'm also in the chorus of those who agree with Vanir that calculated performance figures should not be taken as any indication of a plane's true characteristics.

Cheers. I've faced the Brown argument on another forum before and having looked up the articles for context (as I too thought they seemed a little loose) and concluded a few things:

Brown himself possibly flew the D-11 that was later shipped from England to the US (where it can be viewed today), which at the time nobody actually knew was anything other than a D-9. It is fitted with a different engine, the Jumo 213F (essentially a 213E with MW50 substituting the intercooler). This aircraft of course has two stages on the three gears and above 10500m can get up around 730km/h according to German documents. I doubt very much Brown would've risked destroying the engine by pressing the aircraft to its absolute limits in this fashion (which would've required a dedicated intention and ground support for the purpose), but definitely would've been quite impressed flying this aircraft.

Brown is obviously quoting German documentation for his extrapolated figures (converted to imperial measurements). It isn't until more recently, with a flood of new documentation and common interest that the sheer content and variety of figures which are available for the Dora have been recognised to actually range in everything from calculated figures to flight testing of Ta152 prototypes, and context, references and data gathering technique is best recognised when publishing them, or they aren't necessarily very accurate.

The 213A was put into Doras using C3 fuel, B4 with laderdruck, B4 with two different MW50 systems and just B4 fuel. A 213EB and 213F engine was used, and the project began to run into the Ta152C project, so you have Ta152C fitted with a 213 and Doras fitted with a DB-603. There are calculated figures for just about all of them, flight testing for some, others were interim layouts or transient projects, some were just cancelled. The documentation can be a little all over the place.
In most cases you have to consider a specific Dora tail number and speculate on the fitment and performance of that particular aircraft. It can be a case by case basis.

[paradoxguy]

Originally Posted by vanir

Cheers. I've faced the Brown argument on another forum before and having looked up the articles for context (as I too thought they seemed a little loose) and concluded a few things:

Brown himself possibly flew the D-11 that was later shipped from England to the US (where it can be viewed today), which at the time nobody actually knew was anything other than a D-9. It is fitted with a different engine, the Jumo 213F (essentially a 213E with MW50 substituting the intercooler). This aircraft of course has two stages on the three gears and above 10500m can get up around 730km/h according to German documents. I doubt very much Brown would've risked destroying the engine by pressing the aircraft to its absolute limits in this fashion (which would've required a dedicated intention and ground support for the purpose), but definitely would've been quite impressed flying this aircraft.

Brown is obviously quoting German documentation for his extrapolated figures (converted to imperial measurements). It isn't until more recently, with a flood of new documentation and common interest that the sheer content and variety of figures which are available for the Dora have been recognised to actually range in everything from calculated figures to flight testing of Ta152 prototypes, and context, references and data gathering technique is best recognised when publishing them, or they aren't necessarily very accurate.

The 213A was put into Doras using C3 fuel, B4 with laderdruck, B4 with two different MW50 systems and just B4 fuel. A 213EB and 213F engine was used, and the project began to run into the Ta152C project, so you have Ta152C fitted with a 213 and Doras fitted with a DB-603. There are calculated figures for just about all of them, flight testing for some, others were interim layouts or transient projects, some were just cancelled. The documentation can be a little all over the place.
In most cases you have to consider a specific Dora tail number and speculate on the fitment and performance of that particular aircraft. It can be a case by case basis.

Vanir-

Thanks much for your detailed responses on performance parameters of the Fw 190D-series, including Brown's test reports. Your note provides much greater context for me for the wide variability of recorded performance parameters of the Doras, as well as many other Luftwaffe WWII warplanes, especially the data of the different Fw 190D test hybrids, including early variants of the Ta 152, that are labeled as Fw 190D-9, 190D-12, etc. You also give greater credence to my latent suspicion that Brown was probably citing another Fw 190D-variant when he gave the top speed of the Fw 190D-9 as 453 mph (likely he was quoting the Fw 190D-12).

Perhaps I am expecting too much and/or am not sufficiently aware of the true circumstances at the time, but I am disappointed that Eric Brown did not seem interested in rigorously recording the performance parameter data of the many Luftwaffe WWII warplanes he flew and wrote about. He could have helped develop an invaluable database of performance parameters of WWII German warplanes that would helped debunk a lot of speculation and even myths about the performance of these aircraft. However, I don't want to discount the value of his reports and in fact I thought his written impressions of the Heinkel He 219 Uhu effectively showed that much of its incredible performance parameters did not seem based on fact. I just think he could have done a lot more if he were interested in building such a database.

Taking this idea a few steps further, could the USA and perhaps Great Britain performed a systematic and rigorous test of various Luftwaffe warplanes in its custody and built such a database? They had many Luftwaffe personnel in custody also, including pilots, mechanics, other groundcrew, engineers, and even Kurt Tank and Willy Messerschmitt, who could have helped with the testing and repair (knowing many aircraft were deliberately damaged by its pilots and personnel) of the many Luftwaffe warplanes and their variants available before they were scrapped. Of course, such a programme could have been expensive and not within the US and/or UK military budget and knowing these performance data may not have been a priority at the time. These are just the musings of an armchair WWII aviation enthusiast who always wants more.

PG

[vanir]

I think perhaps the problem with rigorous flight testing of the surviving German aircraft after the war might've been the likelihood of destroying the engine. Allied mechanics were not schooled in maintenance and serviceability routines of German aircraft, particularly the special projects and extreme performance models and at the close of hostilities not altogether too many Luftwaffe personnel were forthcoming in sharing details. Many destroyed their aircraft upon surrender, some would suggest in an attempt to prevent the political grab for technologies associated with the unconditional surrender of a major belligerant nation.

With this in mind some test pilots in England were killed flying German captured aircraft after the war. I think these factors may have put a halt on testing the performance limitations of captured German models, for a regime of technological familiarity instead.
Brown was probably restricted from using MW50 at all, and had capped boost settings for his flights. It's what I would've done had I been in charge. The maximum performance figures can be gained from German documentation, no need to kill pilots postwar over it, and possibly destroy valuable and unique examples of these aircraft.
The documentation at least, in regards to MW50 use on all German aircraft states that it is an extreme emergency system only and should otherwise not be used at all. The maximum safe operation guidelines of up to ten minutes use is muted by a series of warnings that it should in fact only be used for as short a period as possible, no more than one or two minutes with an increased likelihood of engine damage as a result, and has a very highly likelihood of causing immediate catastrophic engine damage if used for more than ten minutes (ie. in eleven minutes you'll be bailing out). This is probably as much caused by the stresses of boosting output some 30% and overspeeding the engine as much as actual cylinder heating.

It should also be mentioned that according to Dietmar Hermann's series on the Fw190D/Ta152 the Jumo 213 was very famous for one thing above all else, poor reliability. Field mechanics and the manufacturer couldn't even agree on an idle speed. Squeezing 2100hp and up from something that's really going hell for leather producing 1750hp is asking for trouble.

In the South Pacific for example, I know that when flight testing for absolute limitations of Japanese models was important (during continued hostilities), the magazines and radios were removed and captured Japanese fighter pilots were used, escorted by Allied fighters. This was only partly due to language issues with the instrumentation, mostly because nobody wanted to lose pilots finding out the limitations of Japanese fighters the hard way.

[paradoxguy]

Originally Posted by vanir

I think perhaps the problem with rigorous flight testing of the surviving German aircraft after the war might've been the likelihood of destroying the engine. Allied mechanics were not schooled in maintenance and serviceability routines of German aircraft, particularly the special projects and extreme performance models and at the close of hostilities not altogether too many Luftwaffe personnel were forthcoming in sharing details. Many destroyed their aircraft upon surrender, some would suggest in an attempt to prevent the political grab for technologies associated with the unconditional surrender of a major belligerant nation.

With this in mind some test pilots in England were killed flying German captured aircraft after the war. I think these factors may have put a halt on testing the performance limitations of captured German models, for a regime of technological familiarity instead.
Brown was probably restricted from using MW50 at all, and had capped boost settings for his flights. It's what I would've done had I been in charge. The maximum performance figures can be gained from German documentation, no need to kill pilots postwar over it, and possibly destroy valuable and unique examples of these aircraft.
The documentation at least, in regards to MW50 use on all German aircraft states that it is an extreme emergency system only and should otherwise not be used at all. The maximum safe operation guidelines of up to ten minutes use is muted by a series of warnings that it should in fact only be used for as short a period as possible, no more than one or two minutes with an increased likelihood of engine damage as a result, and has a very highly likelihood of causing immediate catastrophic engine damage if used for more than ten minutes (ie. in eleven minutes you'll be bailing out). This is probably as much caused by the stresses of boosting output some 30% and overspeeding the engine as much as actual cylinder heating.

It should also be mentioned that according to Dietmar Hermann's series on the Fw190D/Ta152 the Jumo 213 was very famous for one thing above all else, poor reliability. Field mechanics and the manufacturer couldn't even agree on an idle speed. Squeezing 2100hp and up from something that's really going hell for leather producing 1750hp is asking for trouble.

In the South Pacific for example, I know that when flight testing for absolute limitations of Japanese models was important (during continued hostilities), the magazines and radios were removed and captured Japanese fighter pilots were used, escorted by Allied fighters. This was only partly due to language issues with the instrumentation, mostly because nobody wanted to lose pilots finding out the limitations of Japanese fighters the hard way.

Thanks for pointing out the somber realities of testing foreign warplanes, especially those with ill-defined performance envelopes and at the edge of their performance envelopes. Evidently I didn't realize such testing was a much more risky proposition than I previously thought. I guess I had the impression that flying different aircraft was like riding a bicycle--if one is proficient at riding 10-speed and 20-speed bikes, then he/she should have no problems riding others. In a similar vein, I didn't realize that power boosts such as MW-50 were indeed a real emergency option fraught with risk. Obviously flying different warplane models, especially the high-performance ones at their performance limits, is a wee bit more complicated. (I now recall Eric Brown recounting the death of a fellow test pilot flying the advanced Do 335 Pfeil, which was also lost.)

I feel badly for trivializing the very involved process of test-flying potent warplanes. Thanks again for your edifying response.

PG