fiebichpvFebruary 11, 2019, 2:58pm
Shrinking AirBike?
For the past 20 or so years, I have noticed that many of my favorite clothes have been shrinking. Most to the point that I can not wear them anymore and have had to go to progressively larger sizes. This is unfortunate because I really liked my bell bottoms, leisure suit, tie-died & paisley shirts, and puffy ski jacket. Even my winter gloves have had to be exchanged for mittens. Fortunately my flip flops have not shrunk or else I would have to wear old man slippers.
But now what I have come to realize is that wood and steel also shrink...a lot. And it isn't just because it's cold in Kansas during winter. Unfortunately, steel and wood will also shrink during the summer. This is seriously affecting my AirBike. The fuselage cockpit seems to be getting smaller, and the wings are getting shorter. The smaller fuselage is causing an ergonomic problem. The shorter wings result in less surface area and thus less lift causing my takeoff runs to be longer. At the current shrinkage rate, eventually I'll know there is really a problem when I get to the runway's end and still haven't lifted off!
However, there is one aspect of my shrinking AirBike that I have recently been able to compensate for. The control stick. As the plane shrunk, the control stick got closer to the seat which caused a decreased amount of aft stick movement! This is serious because it is more difficult to make a landing flare with only partial stick. I actually have to lean to one side to get the stick back far enough to touch down gently!
Perhaps some of you who have been flying the same plane for a number of years are experiencing a similar unique shrinking phenomenon? Fortunately, I have come up with a solution that you might want to utilize if you also have a shrinking plane.
My solution? I made an offset control stick to replace the original straight stick. Starting with a wooden model to verify the design intent, I then duplicated it in tubular steel. The photos and their titles serve as captions for the process. Recently, I installed the offset control stick and am pleased with its increased movement. I now have more elevator travel and am looking forward to its behavior when flying.
I sure hope this shrinking phenomenon doesn't affect the new stick, if it does, it could get so short that it loses effective leverage! My wife mentioned that my having gained 70# since building my AirBike in 1998 may have some effect. But then, what does she know about airplanes?
Paul Fiebich
Not having all the necessary manufacturing skills myself, I needed to rely on friends to do the welding and machining. Thanks Tom and Steve!
Sorry, the photos didn't come out in the order I had intended. The drawing is right out of the AirBike plans.
For the past 20 or so years, I have noticed that many of my favorite clothes have been shrinking. Most to the point that I can not wear them anymore and have had to go to progressively larger sizes. This is unfortunate because I really liked my bell bottoms, leisure suit, tie-died & paisley shirts, and puffy ski jacket. Even my winter gloves have had to be exchanged for mittens. Fortunately my flip flops have not shrunk or else I would have to wear old man slippers.
But now what I have come to realize is that wood and steel also shrink...a lot. And it isn't just because it's cold in Kansas during winter. Unfortunately, steel and wood will also shrink during the summer. This is seriously affecting my AirBike. The fuselage cockpit seems to be getting smaller, and the wings are getting shorter. The smaller fuselage is causing an ergonomic problem. The shorter wings result in less surface area and thus less lift causing my takeoff runs to be longer. At the current shrinkage rate, eventually I'll know there is really a problem when I get to the runway's end and still haven't lifted off!
However, there is one aspect of my shrinking AirBike that I have recently been able to compensate for. The control stick. As the plane shrunk, the control stick got closer to the seat which caused a decreased amount of aft stick movement! This is serious because it is more difficult to make a landing flare with only partial stick. I actually have to lean to one side to get the stick back far enough to touch down gently!
Perhaps some of you who have been flying the same plane for a number of years are experiencing a similar unique shrinking phenomenon? Fortunately, I have come up with a solution that you might want to utilize if you also have a shrinking plane.
My solution? I made an offset control stick to replace the original straight stick. Starting with a wooden model to verify the design intent, I then duplicated it in tubular steel. The photos and their titles serve as captions for the process. Recently, I installed the offset control stick and am pleased with its increased movement. I now have more elevator travel and am looking forward to its behavior when flying.
I sure hope this shrinking phenomenon doesn't affect the new stick, if it does, it could get so short that it loses effective leverage! My wife mentioned that my having gained 70# since building my AirBike in 1998 may have some effect. But then, what does she know about airplanes?
Paul Fiebich
Not having all the necessary manufacturing skills myself, I needed to rely on friends to do the welding and machining. Thanks Tom and Steve!
Sorry, the photos didn't come out in the order I had intended. The drawing is right out of the AirBike plans.
