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Hi Cyrus, Fred Weick designed the Coupe under a set of Civil Air Regulations roughly equivalent to today's "Utility" category. When the CAN adopted a later set of Civil Air Regulations roughly equivalent to today's "Normal" category, Fred quite logically expected his 415-C to qualify for operations under the latter without modification. This would have meant an increase in allowable gross weight from 1260 to 1400 lbs. In essence, the CAA did not allow evaluation of Ercoupe against its competitors in terms of safety at the increased weight. That would have been a no-brainer. Instead, it made it fly against itself, i.e. to "demonstrate" that it was NO less safe at all conditions of operation at 1400 lbs. than it was at 1260 lbs. The Ercoupe would have even passed that test with no problem. Unfortunately the CAB unilaterally and arbitrarily required that "aircraft charactistically incapable of spinning (i.e. applicable only to the Ercoupe), be evaluated for operation at the increased weight with four degrees greater elevator movement than approval would be actually be granted for use in the field. The original 13º up elevator proved just fine at 1400 lbs., but the would only approve 9º for rigging purposes. Per Ercoupe Information Letter 1 dated Jan. 1., 1956, "In the opinion of the factory, this limitation seriously affected the landing qualities of the Ercoupe (415-D). For this reason the 415-CD was produced instead. (The CD had the 13º up elevator, but reverted to the 1260 lbs. gross.) Bob Sanders' "solution was the "split elevator" used on the 415-E. The center "cutout" reduced the area of that part of the elevator most subject to influence from "propwash", thusly also reducing the difference in behavior of the coupe between power-on and power-off operation. A huge spring was incorporated in the elevator system that made itself apparent when the pilot sought to access the increased "up" elevator necessary for proper flaring. The instructions instructed the pilot only to use this "extra" movement for this purpose, and not in normal flight. All subsequent coupes (415-G, F-1 and F-1A, A-2 and A-2A) retained this setup. The only time you "stall" a coupe is upon landing. Regards, William R. Bayne <____|-(o)-|____> (Copyright 2004) -- On Nov 24, 2004, at 9:45 AM, Dr. Cyrus Wood-Thomas wrote: > Why did some planes get modified to have extra back elevator, on a > spring loaded resistance device, so that the planes could be stalled? > when do you need to stall a coupe? on landing? ========================================================================== ==== To leave this forum go to: http://ercoupers.com/lists.htm Search the archives on http://escribe.com/aviation/coupers/
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