“Fred, you didn't
show the interesting part - which has got to be the
angled axle for this.”
You don’t know the half of it.
I have made many, many modifications to my Lancair IV including designing and building
my own hydraulically actuated speed brakes and servo controlled cowl flaps
among other things. NONE of those little projects held a candle to my
retracting step. What a bitch.
Everything is at a funny angle. The step swings 45
degrees to the fuselage centreline like the landing gear. An over center locking
linkage moves the step and locks it in the down position. Actuation is
via a lever installed in the door sill and pulled up. This way you can
not close the door with the step down. The lever moves an angled push rod
that connects to a bell crank that rotates a shaft through the fuselage wall to
another bell crank which pushes another angled pushrod to the bell crank on the
step. A sp[ring assists motion and locks the linkage over center. The
step rotates in a plastic sleeve bearing which is bolted to the bottom of the
fuselage landing gear via a complex all carbon bearing carrier that has to
carry the weight and bending moment of a 250 pound passenger jumping on the leg.
Big loads need strong structure. And, of course, not enough room.
Everywhere I had to install something, there was not enough
room. The top pushrod even has to bend around the pilot’s inertial
reel mounted on the side wall.
I took the step to OSH some years ago and made a presentation to the Lancair group. My plea: don’t
try this at home.
What a bitch.
However, every time I step into the airplane, I get intense satisfaction knowing
I made the SOB work reliably. The satisfaction of flying is almost
secondary to having the damn step work. (Just kidding.)
Until a heavy weight passenger cracked the step leg in torsion
while stepping up. A day of grinding off cracked UNI carbon and then adding more BID carbon around the leg (not enough room, remember), plus
a bit of filler bog and a coat of paint, and now it is right as rain.
Lesson for all you starting builders: keep is simple and go
flying. My custom goodies drove my build time up to 6000 hours. I
enjoyed it, but I could have been flying years sooner.
Fanatic Fred