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ACRO E-mail Archive Thread: Pitts Landings - "Slipping" vs. "Carrier" approach

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ACRO E-mail Archive Thread: Pitts Landings - "Slipping" vs. "Carrier" approach


Thread: Pitts Landings - "Slipping" vs. "Carrier" approach

Message: Re: Pitts Landings - "Slipping" vs. "Carrier" approach

Follow-Up To: ACRO Email list (for List Members only)

From: Geryl Mortensen <iloop at Onramp.NET>

Date: Sat, 01 Feb 1997 06:26:58 UTC


  Harold James Hitchcock wrote:
> Lastly, can anyone help here on what may have happened.  Practicing rolls
> following a loop in the Citabria.  I initiated a roll at 140mph with a
> pull up and left aileron.  At the top of the roll, the airplane felt very
> tail heavy to the point that I needed to apply ALOT of back stick.  Roll
> was completed, and flight was terminated.  Instructor has no explanation
> for this.  A check of the plane following the flight revealed nothing.
> Any ideas??

Regarding your gremlin in the Citabria, I would guess that you
accidentally bumped into the elevator trim control.  This happens to
everybody at one time or another.  The effect would have been much more
obvious at high speed, in your case after the loop, you said 140 MPH. 
After the roll, you most likely slowed down trying to figure out what
happened and that would take away much of the stick force that you had
just experienced.  Then you said that you landed, so during the normal
landing, you most likely re-trimed the plane for slow flight so that
when you landed the trim would have been in the correct place with
nothing to find during the post flight inspection.

I solved this problem for the most part myself by installing a non slip
surface to my seat that causes my parachute and me to stay in place.  If
you take a look in a lot of cockpits at contests you will find that many
pilots have some provision that will keep them from sliding around, some
have molded seats, some use the same non slip material that I use in my
Staudacher.  It is easy to find at Home Depot, is usually yellow in
color and is used for putting under a "throw rug."  After I attached the
material to my seat in my Staudacher, I found that the gremlin that you
experienced went away, so did my sore body because I no longer hit the
side of the plane when I stopped a fast roll.

The elevator trim tab is very effective at high speeds, the late Rick
Massegee used to do loops with just his trim tab. When bumped at the
wrong time or if you trim for slow flight say before you enter a spin,
you will pay for it as soon as you pick up speed on the recovery.

I hope this helps to explain away your gremlin. Enjoy the sport.
Geryl Mortensen
Dallas, Texas


© Dr. Günther Eichhorn
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