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-----Original Message----- From: Tim and Martha Briggs [mailto:[EMAIL PROTECTED] Sent: Wednesday, November 24, 2004 6:28 PM To: William R. Bayne Subject: RE: [COUPERS-FLYIN] glide and stalls Ercoupers: My 415G will stall, power off, usually dropping off a bit to the right, when you slow up in the normal manner (power to idle, hold altitude) and pull through the spring tension. If you stop at the limit before the spring tension, it just sinks and never stalls ala original Ercoupe. A power-on attempt to stall feels like I'm laying on my back. It seems to enter buffet but is very difficult to get a clean break power on. I have never tried a "whip stall" or uncoordinated stalls (I have rudder pedals)- although I understand the coupes won't enter a spin even if you are cross-controlled and manage to stall. During my training, I vividly remember banked stalls and spinning in a 172. It was probably the most enlightening lesson I ever had. We did stalls while banked, coordinated and then uncoordinated. If you were banked and skidding around the turn (too much rudder), the normally docile 172 would instantly drop off into a spin when you stalled. If you were banked and slipping,(not enough or wrong rudder input) the stall was docile and you just stalled banked. I have yet try stalling my Ercoupe while banked and skidding or slipping. Exploring that region of the flight envelope just doesn't appeal to me. Maybe sometime with a seasoned CFI or aerobatics pilot. Is there any info out there on how the Coupe behaves in a banked, uncoordinated stall?? Thanks Tim Ercoupe 415G N94413 -----Original Message----- From: William R. Bayne [mailto:[EMAIL PROTECTED] Sent: Wednesday, November 24, 2004 12:16 PM To: COUPERS-FLYIN Subject: Re: [COUPERS-FLYIN] glide and stalls ----[Please read http://ercoupers.com/disclaimer.htm before following any advice in this forum.]---- Hi Ron, I can understand your conclusion based on the information generally available. I will share some additional information I have in Fred Weick's unpublished notes because the "good of the fleet" is better served now than by later publication. "Power On Stall: The Ercoupe can be flown into a power on stall by rapidly pulling the control wheel back from level flight, or from a full power normal climb. This rapid movement of the control wheel causes the energy due to forward speed to be spent in climb, resulting in an angle of attack greater than the minimum flight speed angle of attack. At this angle of attack the Ercoupe wing is stalled and the airplane pitches sharply to pick up flight speed. Even though the wing is stalled in the above maneuver it quickly recovers and the ailerons used in lateral control become immediately effective. Due to the inherent aerodynamic balance of the aircraft and its controllability at high angles of attack autorotation, or a spin maneuver is impossible in a power on whip-stall". Elsewhere it is made repeatedly clear that the condition of "minimum speed" or "minimum flight speed", power on or power off, is created by slowly moving the control wheel back to the stop and allowing both speed and angle of attack to stabilize. Fred continues: "It is possible to stall the Ercoupe by pulling the aircraft into a high angle of attack with a rapid aft movement of the control wheel from any speed above its minimum flight speed. At a high angle of attack in which a smooth flow of air over the wing is broken up and becomes turbulent the center section flow becomes turbulent first, due to the effect of center section fillets. This turbulence moves back over the horizontal tail reducing its down force which in turn causes the nose to pitch down permitting the aircraft to pick up normal flight speed. Due to the fact that the center portion of the wing is most affected by the high angle of attack, the outer portions of the wing panels remain stalled for only a short time. As a result the ailerons regain their effectiveness almost immediately." Fred also stated: "It is possible to stall the Ercoupe by pulling the aircraft into a high angle of attack with a rapid aft movement of the control wheel from any speed above its minimum flight speed." His description of the power-off stall was essentially identical, additionally stating: "SInce the wing panel tips keep within their smooth air flow during a hign percentage of the stall the ailerons are effective in counteracting any roll which may occur as a result of the stall. Power-off stalls should not be precticed close to the ground since approximately 200 feet are required in order for the Ercoupe to get back into a normal gliding attitude" So you can now see that the Ercoupe will NOT "stall" in the sense contemplated by comparison with lesser designs, or as arbitrarily "required" by new Sport Pilot rules. On the other hand there very much does exist the Ercoupe airbourne "whip-stall"! Fred elaborated on this too: "Several accidents have occured because the pilot suddenly pulled the wheel back after a fast landing, and after the plane ballooned into a high angle of attack he pushed the wheel forward to put the plane on the ground again. This caused the wings operating at low speed and high angle of attack to lose their lift and as a result the plane struck the ground with the nose gear taking sufficient impact to cause considerable damage." Clearly this describes an inadvertent and uncorrected "whip-stall" while landing. For any Ercoupe pilot in this situation, know that recovery is not only possible but immediate upon application of sufficient (full) power to reestablish normal flight ASAP. Then the landing may be continued (remaining runway permitting) or a go-around initiated, but the "drop" to the runway with insufficient flying speed is averted as is related damage. The many wrinkled and replaced firewalls on Ercoupes flying today are irrefutable evidence of inadequate pilot instruction or understanding by owners prior and/or present of Ercoupe stall characteristics. The Ercoupe is one of the the most versatile designs of general aviation, and the most forgiving to those who understand and respect how truly unique it is. Every machine that takes to the air has a "dark side" to its operating envelope that awaits the ignorant, the lazy and the careless. Regards, William R. Bayne <____|-(o)-|____> (Copyright 2004) -- On Nov 24, 2004, at 11:50 AM, Harden wrote: > I am new to the Ercoupe. Based on the studying I have done, I have > concluded that the only time the Ercoupe wing quits flying completely > is when the wheels are on the ground! I have concluded that there is > no such thing as an Ercoupe airborne stall. There is only an > accelerating sink rate as the airspeed over the wing decreases and a > partial wing stall starting at the root of the wing is created. > > The diagrams on page 13 of one of the owners manuals I have > illustrates this rather well. > > Ron Harden ========================================================================== == == To leave this forum go to: http://ercoupers.com/lists.htm Search the archives on http://escribe.com/aviation/coupers/ ========================================================================== ==== To leave this forum go to: http://ercoupers.com/lists.htm Search the archives on http://escribe.com/aviation/coupers/
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