Messerschmitt AG.
Speed Measurements on
Airplanes With Specially Treated
and Standard Production Surfaces
 Test Report
109 11 L 42
 Date 9.7.42
 Copy 3
 Dept. Flight Testing

Reason:It should be examined whether by a special treatment (putties, sanding, and special paint) of the entire airplane surface, in the context of a quantity production, an improvement of the airspeed is obtained as compared to normally treated production machines.
4 normal and 4 specially treated 109 G 2 production machines were obtained from the Wiener-Neustäder aircraft factory. An Augsberg pilot conducted test flights over the Wiener-Neustädter test course.
Results:An average speed of 327 mph (527 km/h) for the four specially treated machines and 322 mph (519 km/h) for the four production machines results based on a normal day and 820 ft altitude with a boost pressure of 1,30 kg/cm2 and an average blower pressure of 1,80 kg/cm2.
 An average speed increase of 5 mph (8 km/h) can be obtained through special treatment of the surface.
 A minor change of the absolute values is to be expected with the review of the test course.

Werk nr.
Serial Nr.
Test stand-
power Ps
  3,513 438      CC + ZM 77 265  13.15539
  213 439      CC + ZN76 861  13.16288
  1,413 440      CC + ZO76 854  13.16798
  613 442      CC + ZQ76 875  13.15429
  713 448      BC + VK25 562  13.16836
  813 496      BC + VS25 554132213.17406
  10,1113 500      BC + VW25 516128315.4538  
  913 506      BJ + WC26 592128315.4518  

Engine: DB 605 A     Serial Nr. See above.
Propeller:3-flg. VDM-Adjustable blade
D = 3,0 Serial Nr. See above

Surface:Production machines: Flying paint 7122(Probe)
 Special machines:
 W.Nr. 13 438Putty 198,Flying paint 7109
 W.Nr. 13 439Putty Finish 199
 W.Nr. 13 440PuttyFinish 199 (Probe)
 W.Nr. 13 442Putty Finish 199
  Upon completion above and below with insulating paint IS 238.
 Color creator (Warnecke u.Böhm)
Application technique see tour report from Mr. Hagg from 21.10.41 (putties, Ziehen, sanding, spray.

Condition of
the Aircraft
G2 series with single-wire antenna, without main wheel covers and without pressure-installation. During all flights outside air thermometers on the right upper side of wing in 2/3 of the wing depth; during the flights 1 to 6 and 9 radiator flap indicator staffs (435 mm long, 8 mm of Ø) attached in the center of the radiator flap.
The water radiators were closed by hand during the measurements, i.e. the intake amounted to 54 mm according to the f-kinetics, while the outlet was pushed open to 35 mm.
Date of
1.7 – 6.7.42
The flights were conducted over the Weiner Neustädter test course. The particular points of the test course were demonstrated to the pilot and observer during a familiarization flight. The two runs are under an angle of 46 ° to each other (90 ° desirable).
The approach for route 1 runs across a large part of the city, while the check points at Wöllerdorfer street underpass and Steinabrückler street crossover are quite well located. The course is 21,982 ft. and the path passes over open meadows. The approach for route 2 crosses a small settlement while the approach for route 3 again runs over the city. As the end of the 23,622 ft. long run 3 and the Pottendorfer line is along a very protracted fork the test course crosses perpendicularly behind the one 66 ft tall high voltage line. This is disturbing naturally, also during the approach of route 4. Due to these facts measurements cannot be accomplished with the accuracy such as e.g. that attained at the Augsberg test course. Particularly unfavorable is to stop at the course fork, so that here the danger of a faulty measurement is shown not from the hand, especially with application of all cross winds the tendency was determined, routes 3 and 4 were flown through faster than routes 1 and 2. Unfortunately protocols on measurement of the course or measurement table sheets were unavailable to check the actual length of the course over flown. Nevertheless these factors have no influence on the accuracy of the speed comparisons. The absolute values are provided however with a tolerance of approximately 4 mph. The precise data values shall be given in the next report, after the test course is measured.
The flights were monitored by recorder for altitude, trip, boost and blower pressure.

    2323  (520)321  (517)323  (520)Paint easily cracked
    3322  (518)327  (526)329  (529)Böig
    4319  (514)326  (525)328  (528)
    5321  (517)327  (526)329  (529)Wiederholung v.3
    6323  (520)326  (525)328  (528)
    7319  (514)320  (515)322  (518)
    8323  (520)322  (519)322  (519)
    9321  (517)323  (520)323  (520)
  10321  (517)320  (515)322  (518)
  (Speeds given in MPH, values in parenthesis in km/h)

  Vw represents the true speed on the test day at test altitude with actual engine power, while Vn represents the speed on a Normal Day at 820 ft altitude with 1,30 kg/cm2 boost and 1.80 kg/cm2 blower pressure. With Vnk a speed loss of 2 mph (3 km/h), caused by the radiator indicators, is taken into account.

For average comparison values, 327 mph (527 km/h) at 820 ft altitude and 323 mph (520 km/h) at Sea Level is obtained with specially treated machines. The corresponding values of the standard production machines are 322 (519) and 318 mph (512 km/h). The speed increase thus averages 5 mph (8 km/h).

The treatment of the special surface, requested as per information from Mr. Werksleiter builder WNF, caused a longer working time of 107 hours as compared to 60 hours for the standard production surface. However, in order not to interrupt production within a reasonable time, extensive equipment is necessary. For drying lasting several hours, heating equipment must be developed in order to dry the machines under the hall roof. Due to lack of space another solution to this problem would not be possible.

According to our view the speed gain was caused not so much by the paint application but rather by priming and other significant special treatment, which always is the case with a non production machine. See enclosed paint samples. These do not show a noticeable surface difference.

Augsburg, 15.7.42
  Messerschmitt AG. Flight Testing.     Group:   Performance.            Official in charge: Karstedt

See Table showing sea level performance from above test after corrections and in condition of basic model. (From: Zusammenstellung aller Leistungsmessungen umgerechnet auf Grundausführung, 14.1.44).
Geschwindigkeitsmessungen an Flugzeuge mit sonderbehandelten und serienmässigen Oberflächen

WWII Aircraft Performance   Me 109 G Flight Tests