On Oct 17, 2004, at 10:23 AM, Thomas wrote:
I am thinking of buying an Ercoupe and I'm a little concerned about gross weight. I weigh 245 and my wife weighs 185 I have been to flyins and have seen 2 good size adults get out of these planes, but when I run the numbers it doesn't seem to work. Would cross countries be out of the question?
Hi Andy,
Your concern is valid. Your situation is another where you must weigh your real needs (as opposed to unrealistic wishes) and what the right Ercoupe can do.
Ercoupes were built with 65hp, 75hp, 85hp and 90hp. STCs exist to rebuild a 75/85hp engine to be capable of producing 96-97hp or fitting an 0-200 (100hp). They will all cruise 100+ mph.
Don't consider a prewar 65hp coupe. 75hp postwar coupes weighed approximately 803 lbs. with starter, generator, voltage regulator and battery. Allowable gross was 1260#. Initial Rate of Climb at sea level was 530 fpm with a wood prop (560 with a McCauley metal prop). Service ceiling was 14,000 ft. Addition of a second wing tank increased range to 503 miles at 102 mph.
The 75hp 415-D weighed 815 lbs with an allowable gross of 1400#. Initial Rate of Climb at sea level was 550 fpm with the standard (wood) prop and 560 with the McCauley metal prop. Service Ceiling was approximately 12,000'.
The 85hp 415-E weighed 815 lbs. The 415-G weighed 830 lbs. At 1400#, initial Rate of Climb at sea level was 525 fpm, and "useable ceiling" 11,000'. Cruising "leaned" at 5,000', range was 514 miles at 107 mph..
The 90hp F-1, F-1A, A-2, and A-2A weighed 890 to 950 lbs (with metalized wings), the latter three with allowable gross of 1450#. Service Ceilings were claimed from 15,500' to 17,300 and cruising speeds of 117-125 mph. Range was 467 to 516 miles with reserve. Alon claimed a Rate of Climb of 640 fpm.
The 90hp Mooney M10 weighed approximately 950 lbs. Per the Owners Manual, Initial Rate of Climb at sea level with a 7153 prop was 630 fpm, and Service Ceiling (still climbing at 100 fpm) approximately 12,500'. One could cruise 103 mph "leaned" at 12,500' burning 4.2 gph. A range of 453 miles was claimed, even though Mooney claimed a range of 453 miles and considered only 22.1 gal. (of 24 gal. fuel capacity) to be "useable.
If you WANT to fly a coupe, just limit legs on cross countries to the safe range of early 65hp coupes (320 mi.). In another earlier thread I explained how to measure and monitor this accurately. Take off with 15.5 gal. usable fuel and you have 1/2 hour reserve at 4.2 gph.
Look for a 415-D, E or G coupe that weighs 830 lbs or less (or strip the paint, clean out the yuck, old radios, excess upholstery, AN instruments, etc). The plane (830) + fuel (93) + oil (8) + you and your wife (430) from a 1400# gross leaves 39 lbs. for baggage, handheld radio, headsets, intercom, handheld GPS, OSA and transponder. It CAN be done. Better still, find a rag wing bird with a C-90 or 0-200.
Aviation is full of similar compromises and trade-offs. Cross country flights are not "out of the question". Full tanks on takeoff are. If you want a coupe enough to fly it knowledgeably, always remember that the heavier the plane is, the lower the Rate of Climb, Service Ceiling and Range for any given altitude, pressure, temperature and humidity.
Was Fred being a little conservative with his numbers or is this a recipe for disaster?
Fred was ALWAYS conservative with his numbers. That's why Forney was able to get another 50 lbs. gross approved (which benefitted Alon and Mooney).
If you respect the coupe enough to intelligently understand and manage the variables, it will forgive you transgressions other aircraft won't. The things it will not forgive are few and easy to avoid. Just read (and follow) the instructions.
A coupe is more magic carpet than recipe for disaster. Trade-offs should be properly identified and realistically accounted for before operating any aircraft anywhere at any time.
Regards,
William R. Bayne
