That might refer to the airstream over the tailplane being disturbed or blanked by the mainplane at high AoA. Especially noticable in T tails like the Boeing 727 or the Piper Tomahawk. Can make spin recovery difficult.
John Martindale 29 Jane Circuit TOORMINA NSW 2452 AUSTRALIA ph: 61 2 66584767 email: johnja...@optusnet.com.au website: www.members.optusnet.com.au/johnjanet/Martindale.htm ----- Original Message ----- From: "D F Lively" <riksh...@interl.net> To: "KRnet" <kr...@mylist.net> Sent: Friday, April 14, 2006 9:11 AM Subject: Re: KR> Horizontal stab stall > John: > > It seems to me there was an issue called the "Secondary Stall" that my > instructor said was potentially very dangerous but that was 43 years ago > and > beyond a vague recollection I recall little of the issue. My training was > in > Cessna 150s. > > Don > ------------------------------------------------------------------------ > > Martindale Family wrote: > >> Hi Bill, >> >> Please elaborate on the Aerospace Department's conclusions. >> >> Seems to me a pitch up would occur in these circumstances only if the >> aircraft had its weight behind the CoG and that component is in excess of >> the lift available from the tailplane under forward stick. Obviously I'm >> missing something here and why isn't it reported from other Diehl wings >> currently flying. I agree, whatever it is it is potentially dangerous. >> Critically, does the nose actually drop at the stall itself after the >> pitch >> up immediately prior it? >> >> Cheers John >> >> John Martindale >> 29 Jane Circuit >> TOORMINA NSW 2452 >> AUSTRALIA >> >> ph: 61 2 66584767 >> email: johnja...@optusnet.com.au >> website: www.members.optusnet.com.au/johnjanet/Martindale.htm >> ----- Original Message ----- >> From: "countryhomeprint" <countryhomepr...@bellsouth.net> >> To: "KRnet" <kr...@mylist.net> >> Sent: Friday, April 14, 2006 6:47 AM >> Subject: KR> Horizontal stab stall >> >> > KR-netters >> > >> > After consulting with the Aerospace Department at Mississippi State >> > University concerning the pitching up of my KR-2 upon stall approach, a >> > probable cause has been reached. The Horizontal Stabilizer is stalling >> > prior to the wing stall. This may be caused by the longer wing by Dan >> > Deihl. This creates a very dangerous condition. There are three ways to >> > prevent this condition. (1) Increase the stabilizer area by increasing >> > by >> > several inches the length of the stab. The standard flat stabilizer is >> > only about 50% as efficient as a stabilizer with a true airfoil which >> > leads to the 2nd method of prevention. (2) Change the stab airfoil to a >> > true airfoil which will increase the efficiency of the stab. And (3), >> > Don't stall the aircraft, keep the airspeed well above stall. >> > It has been noticed that some KR-2 builders constructed a true airfoil >> > rather than the flat stab shown in the plans. Maybe it should be noted >> > to >> > other KR builders to do the same. >> > You guys who have true airfoil stabs, where did you get your plans, >> > technical info., etc. I would like to change my stab to a true airfoil. >> > >> > Maybe if I put Armorall on my horizontal stabilizer my problem will be >> > solved. >> > >> > I'm still finding dingle berrys after that close call. >> > >> > Bill Page >> > boliverp...@bellsouth.net >> > _______________________________________ >> > Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp >> > to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net >> > please see other KRnet info at http://www.krnet.org/info.html >> >> _______________________________________ >> Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp >> to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net >> please see other KRnet info at http://www.krnet.org/info.html > _______________________________________ > Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp > to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net > please see other KRnet info at http://www.krnet.org/info.html
