Classic Designs > Classic Planes

4" Bellcranks, are they necessary in Classics??

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Ron King:
When I built my first Oriental, after returning to the hobby, I calculated the angular deflection of the 3 inch bellcrank versus the 4 inch bellcrank. I determined where I needed to drill the push rod hole based on these calculations to make the control systems equal and built the plane with a modified 3 inch bellcrank.

To this day, I cannot tell the difference at the handle when I'm flying. The controls in my classic Oriental move the same as the controls in my big ship. I want and need this similarity because I don't want to waste time getting reacquainted with each plane.

My .02,

Ron

phil c:
the biggest thing I see is that using a larger bellcrank gives you the OPTION of slowing down the controls and, even bigger, reducing the pushrod and bearing loads.  If you use the exact same geometry on a 3 in. bellcrank setup and a 4 in. bellcrank setup the 4 incher puts a lot less load on the pushrods.  Also, as Tom points out, the smaller bellcrank reacts faster to a standard 4 in. handle and going to an adjustable handle with the lines attached outside your knuckles makes the control forces you feel go way up.  The overhang between the handgrip and the lines is just another lever- the longer it is, the harder it is to move the controls.  The old EZ Just got it almost exactly right for most people with only an inch or so of overhang.

Leo Mehl:
In the 60's we used very fast controls which meant that we had to stay at a constant attention during maneuvers. The total leadout pull from neutral was about one inch or less. I have built two classic planes lately and I went from an inch to about 2". What a difference this made as far as flying a classic plane. I have seen some of the Orientals that Don McClave has built and he still makes his controls fast. In any case the classic plane flys better with slow controls. Also most classic planes have shorter tail moments. y1 y1 y1 y1 y1

doug coursey:
don still used 2 3/4 inch bellcranks in his stuka stunt with 45 degrees of flap and elevator....i know its old but i had to post this because im building a stuka stunt and going with an Okie 3 1/2 inch bellcrank. the wing is on the small side 47" wing span. 

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