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As someone who spent a great deal of time in low speed aerodynamics, stalls in the LIV or other lancair models can be improved greatly with the correct addition of Flow Strips (stall strips). They are not just glue on and the stall is improved but when you correctly apply them the stall will be improved (stall warning plus some prestall buffet) significantly. This is normally done with only a 1 or 2 knot change in stall speed. This normally will not affect the spin charastics.
Jack Webb
L360, LIV
AeroSpace Engineer BSAE
FAA Designated Check airman for C421, C404 & C310
ATP, CFI Airplanes & Instruments, Multi, & Sea
Numerous Jet Type Ratings
Experienced Experimental Test Pilot both multi and single engine aircraft
Former Chief Engineering Test Pilot for a Major Manufacturer
Ohio
From: John Hafen <j.hafen@comcast.net>
To: lml@lancaironline.net
Sent: Friday, June 24, 2011 11:02 PM
Subject: [LML] Re: Airplane needs to be "fixed," Stall Speeds, Wing Cuffs, Vortex Generators for L...
One has to choose between stall strips and a heated leading edge.
For me personally, stall strips would be more applicable for my Cub, which doesn't need them at all. And I have been in inadvertent icing conditions in the IVP and watched the ice curl up like potato chips and blow away. I'll keep the heated leading edge, thank you, rather than a stall strip that I would never use.
And as far as a larger tail??? A. Who is going to spend the additional money to make their IVP look stupid? B. The IVP is tail heavy already -- no one wants to load extra weight aft of the CG. C. Challenged pilots should perhaps fly a different plane.
I love the IVP the way it is. I have never crashed and died. I understand the envelope, and like
it;)
John
(On military pilots and "training" to fly unstable air craft -- I don't think you are accurate on this one. The F-16 is so unstable that it requires 20+ inputs per second to maintain straight and level flight. It is computerized. No human being on earth, no matter how highly trained, can manually fly an F-16 straight and level. The "fly by wire" F-16 is way easier to fly than my IVP. The original side stick didn't move at all, but responded to pressure. Pilots hated it so it was redesigned to move slightly. And the pilots wishes to go a computer that controls the flight surfaces. There is no direct manual connection from the stick to the flight control surfaces. Even in the old F4, the flight control "feel" was artificial -- based on springs, as the hydraulic system supplied 3,000 psi to the flight control surfaces, which came in really
handy over about mach 1.1. You don't need a million dollars worth of training to fly a IVP safely. HPAT, yes.) On Jun 24, 2011, at 11:24 AM, Wolfgang wrote: Military aircraft are unstable to allow better agility. Military pilots get over a million dollars worth of training each to be able to handle their "unstable" aircraft. I don't see that happening for IVP
drivers. There are a couple of things that can be done that don't adversely affect performance or handling. Stall strips and larger tail feathers come to mind. Wolfgang | | Wolfgang states: "If the airframe can't get back in the envelope, then the airframe needs to be fixed."
There are lots of historical examples to the contrary, like the F4 Phantom. Once in a flat spin, the plane was unrecoverable from any altitude. "Stick Forward, Ailerons and Rudder Neutral, If not Recovered, Maintain Full Forward
Stick and Deploy Drag Shoot" were not enough.
Yet the F4 was the work horse fighter for the Navy, Air Force, Marines, and hosts of allies for decades. And it was fast, over Mach II.
Yet, you stayed far far away from "departing" -- high angle of attack, stick one way and the rudder the other.....
Most advanced stalls in IVP are recoverable, given 10,000 feet or so.
But unlike the F4, most of our IVPs are not equipped with Martin-Baker ejection seats.
The F4 never got
fixed. The IVP got "fixed." It's called the "ES," with larger differently shaped wings and fixed gear, that became the Columbia/Cessna.
The "fix" was a series of tradeoffs that IMHO made it a less desirable plane -- slower, fixed gear, non-pressurized.
I'll happily keep the un-fixed version of the IVP myself, thank you.
John Hafen
On Jun 23, 2011, at 9:11 AM, Wolfgang wrote: I, for one, want to be able to recover from an "adverse" condition should I ever find myself in one. Knowing where the edges of the envelope are and how to get beck in the envelope should be required. If the airframe can't get back in the envelope, then the airframe needs to be fixed. Wolfgang ----- Original Message ----- Sent: Wednesday, June 22, 2011 2:12 PM Subject: RE: [LML] Re: Stall Speeds, Wing Cuffs, Vortex Generators for L...
David,
I have no problem with anyone who wants to explore the “envelope” of his/her airplane. However, I take great exception to
you grounding me because I might choose to not get as near to the edge as you.
Lynn Farnsworth Super Legacy #235 TSIO-550 Powered Reno Race #44 Mmo .6
I agree 100% also. If you don’t know what the incipient stall feels like in the stick and the airframe you should not be flying the Legacy or 320’s. (Not knowing this is the single biggest killer of Lancair pilots.)
David T. Legacy
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