Messerschmitt AG. Augsburg Speed Measurements on Airplanes With Specially Treated and Standard Production Surfaces Test Report Nr. 109 11 L 42 Date 9.7.42 Copy 3 Dept. Flight Testing GroupPerformance 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. Test- Procedure: 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. Flight: Aircraft: Werk nr. Registrations: Engine: Serial Nr. Test stand- power Ps: Propeller 3,5 13 438 CC + ZM 77 265 13.15539 2 13 439 CC + ZN 76 861 13.16288 1,4 13 440 CC + ZO 76 854 13.16798 6 13 442 CC + ZQ 76 875 13.15429 7 13 448 BC + VK 25 562 13.16836 8 13 496 BC + VS 25 554 1322 13.17406 10,11 13 500 BC + VW 25 516 1283 15.4538 9 13 506 BJ + WC 26 592 1283 15.4518 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. 13 438 Putty 198, Flying paint 7109 W.Nr. 13 439 Putty Finish 199 W.Nr. 13 440 Putty Finish 199 (Probe) W.Nr. 13 442 Putty 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. Pilot: Schmid Date of Flights: 1.7 – 6.7.42 Test Procedure: 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. Results: Flight Vw Vn Vnk Remarks 2 323 (520) 321 (517) 323 (520) Paint easily cracked 3 322 (518) 327 (526) 329 (529) Böig 4 319 (514) 326 (525) 328 (528) 5 321 (517) 327 (526) 329 (529) Wiederholung v.3 6 323 (520) 326 (525) 328 (528) 7 319 (514) 320 (515) 322 (518) 8 323 (520) 322 (519) 322 (519) 9 321 (517) 323 (520) 323 (520) 10 321 (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 FEV/EK/Go.
Posted on: Tue, 04 Jun 2013 22:26:34 +0000
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