Bill,
I'm making sure I know what you mean that's all.
The tests presented on Mike Williams site were carried out with a underperforming batch of engines, hence the results. Lutz notes this on William's site as-well. Sorry for not addressing this earlier, guess I thought I already had.
As to the physics, again they dispute what Caldwell claims. But tell me what effect does an increase in power with a decrease in drag and no change in weight normally have on an a/c's performance? I understand you have a good understanding on aerodynamics so this should be easy really.
Finally let me point out that it is Caldwell's claim I don't believe.
Soren - the comments about the underperforming engines are made by Hermann in this report... which is why I went to the discussion regarding 2.02 ata and best theoretical results based on wind tunnel drag numbers.
As you noted, I DO understand the physics of increased power even with
same drag (no evidence of 'decreased drag other than artificially covering engine gaps and wheel covers - neither of which would exist in the field).
You seem to be sliding into old habits of sarcasm?
I also understand that calculated results are rarely attained in flight test because wind tunnel models are exceptionally clean in contrast to operations... ditto engine performance from one airplane to another which is why aircraft are generally picked at random - at least in USAAF and USAF tests.
So Hermann points out that the properly performing Jumo 213A would yield 70-100 hp more than the October 1944 test results - but would NOT attain the best 'theoretical' results which uses all the optimal factors never achieved by a production Fw 190D-9 according to him (and the caveats I cited in the above thread). He also pointed out that the -12 propeller seemed to boost the performance over the -9 prop.
Back to Caldwell as you didn't seem to finish your thoughts on him. I didn't read that as 'his words', but as a reproduction of a diary compiled by III./JG54 pilots recounting their experiences with the D-9 in December-January operations.
In other words Caldwell was not 'claiming' anything, just presenting other's words. You may have a more complete source to references which refutes the operational observations of those pilots. I haven't seen such but doesn't mean they don't exist.
Back to Mike Williams reproductions of Hermann's reports and comments - Is Hermann incorrect, are the flight tests and theoretical max performance incorrect?
There is a difference between the two (underperforming engines cited versus theoretical) in the 13-20 mph range for boost and surface condition similarities - but in every case that I read, 1900 hp Jumo 213A in 1.85ata and Max Take Off/War Emergency Power, was the cited 'max' conditions for the tests.
Do you have operational evidence that was exceeded in combat for the Dora 9?
Last - the below tests in March 1945 clearly state that the D-9 below was a production aircraft tested with properly adjusted engine..so I would think this series of data should meet objective scrutiny?
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E-Stelle
Rechlin Flight Performance Fw 190 D-9
with Jumo 213 A. Erpr. Nr.9003
Teilber.2.
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2 March 1945
Summary.
Flight performance of the Fw. 190 D-9 (production version) is given. Speed at altitude was flown with Serial Nr. 006. Various aircraft were checked at 3,000 rpm during continuous testing. Speeds reached 323 to 329 mph (520 to 530 km/h) at sea level and 388 to 395 mph (625 and 635km/h) at 21,325 ft (6.5 km) (about full throttle height, depending on engine adjustment). With 3250 rpm, speeds reached 335 to 342 (540 and 550 km/h) at sea level and 401 to 407 mph (645 and 655 km/h) at 21,653 feet (6.6 km). With 3250 rpm and a take-off weight of 9,480 lbs (4,300 kg), rate of climb was 3,329 ft/min (17.0 m/s) at sea level and 392 ft/min (2.0 m/s) at 33,465 feet (10.2 km).
I. General information.
Airplane model : Fw 190 D-9 W. –Nr.210006
Aerodynamic Wing Area : F = 18,3 m2
Wing span : b = 31,32 ft (10,46 m)
Wing aspect ratio : R = 6,0
Engine : Jumo 213 A (B-4 fuel)
Engine power permissible for 30 min : 3250 rpm
Engine power for continuous operation : 3000 rpm
Air Intake : external scoop without filter
Exhaust system : plain blow back stacks
Pitot tube installation : Bruhn 5 d
Propeller : Heine, 3 blades, compensating core, D = 3,5m, t/D = 11,5%
Aircraft condition:
Standard version with ETC 504 (without wheel cover).
Engine: without gap gasket
Surface: standard, primed and sprayed
Armament: 2 mg 131 in the fuselage with 475 rounds
: 2 mg 151 in the wing with 250 rounds.
Antennas: for Fu G 16
" Fu G 25
" equipment
and directional loop cover.
Take-off weight: 9,590 lbs (G = 4350kg) (after n.J.190.213-045 v,31.7.45)
Fuel contents: 141 gallons (640 liter), of which 25 gallons (115 liter) is in the supplementary fuselage tank.
10,229 lbs. (4640 kg), if flown with 300 liter drop tank.
II. Performance tests.
Speeds were ascertained from dynamic pressure tests. Calibrated measuring instruments were used. The interesting Va-area was reached by flight measuring on the test range.
The rates of climb were measured with a carbon recorder.
III. Results of the tests.
The results are on graphs 5 to 9. The level speeds were reached with different engine rpms. It is remarkable that speeds were around 9 mph (15 km/h) higher in the past with Serial Nr. 006 at 3000 rpm (see report of 15.11.44). The current speeds were reached after installation of a new engine, correct engine adjustment, and with the standard propeller. Performance shown in the report of 15.11.44 was determined, through continuous testing, with an unadjusted engine and a D-12 propeller. The speed loss is therefore from engine and propeller differences (D 9 and D 12 propeller).
1.) Level Speeds. They are shown on sheet 5 and apply to a nominal weight of 9,259 lbs. (4200 kg). The V curves are drawn in throughout the entire speed range, so that one can read off the associated Va at each height to each Vw. Sheet 6 shows the dependence of the airspeed on the flying weight and sheet 7 the influence of a 66 gallon (300 l) external tank on the speed.
Example:
Search: Speed at 26,246 feet with a weight of 9,700 lbs, 66 gallon drop tank height, and 2300 rpm.
Given: at 19,685 feet and 9,259 lbs, as per sheet 5, without tank, Vw = 334 mph (538 km/h), Point I: Va = 252 mph (406 km/h ) Weight influence: (as per sheet 6) Va = 252 mph (406 km/h) with 9,259 lbs (4.2 kg) register, point II, draw parallel up to 9700 lbs (4.4 kg), gives new Va (point III). (Δ Va = -6) km/h
Va = 400 km/h
External tank loss (as per sheet 7, Fig.b, point IV: (Δ Va = -20) km/h
380 km/h
The final Va = 380 km/h is registered on sheet 5 (H = 6 km.) Point V and perpendicularly under V on H = 0 km, in the example looked for Vw = 506 km/h read off, point VI.
2.) Climb performance.
It is shown on sheet 8 for 3000 rpm and 3250 rpm
Va climb SL - 22,966 ft Va = 174 mph
26,247 ft Va = 168 mph
29,528 ft Va = 163 mph
32,808 ft Va = 158 mph
3.) Radiator flap test flight.
The influence of the radiator flap position on speed (with empty drop tank) was determined at 6,562 feet with 2700 rpm, (see sheet 7, Fig.e). The entire opening was divided into 10 equal parts, "0 = completely down" and "10 = completely up". The test shows that the speeds are greatest with a 2,3 radiator flap position (approx. flush), i.e. the speed loss is lowest. If possible, level flight should be flown at this position.