Use of hardwood in the Fairlead Block

[Brian Jackson]

Greeting fellow Bee Brethren,

Quick question:
The GyroBee documentation calls for a hardwood insert in the fairlead block (the part directly under the mast below the tailboom tube) that offsets the rudder cables. What kind of tolerance should I allow for expansion of the wood due to humidity? Or is this not a problem if it's sealed properly with, say, spar varnish? I'd like a precision fit, but don't want to stress the Aluminum casing if too tight should the hardwood want to expand a bit.

Thanks,
Brian Jackson

[Brian Jackson]

One other thing... If there is any tolerance, it should be very small such that the 3/32" rudder cables cannot bind between the hardwood block and the fairlead casing. The fairlead block is designed such that the cables can be easily freed if needed by simply removing the fairlead bolt and sliding the hardwood insert out of the casing. That's why there's 2 grooves in the hardwood rather than thru-holes for the cables. At least that's my best guess.

Thanks,
Brian Jackson

[gyropilot]

The GyroBee documentation calls for a hardwood insert in the fairlead block (the part directly under the mast below the tailboom tube) that offsets the rudder cables.Brian,

I can't answer your question related to the wood swell issue, but I just thought I'd like you know I used white Nylon plastic instead. Pretty much any type of wear resistant Nylon or polyethylene will work. However, with plastic prices the way they are, it'd be *much* cheaper to use wood.

If you care to consider using plastic, you might check out the US Plastics web site (http://www.usplastic.com/catalog/product.asp?catalog%5Fname=usplastic&category%5Fname=75&product%5Fid=4629) for reasonable pricing. Look for part number 47770, which is 2" x 2" natural Nylon bar at $26.10 per foot.

Regards,

John L.

[Brian Jackson]

Thanks, John. It's a bit salty price-wise, but worth checking into. You've done such an amazing job on your Bee that I may follow your lead on this one.

Take care my friend.
Brian Jackson

[StanFoster]

Brian: I would use something else besides wood. Wood will swell several percent its width across its grain....however...it does little movement with the grain. I have to allow for this in my stairways just between the summer cooling and winter heating cycles. Its all in the humidity. Something inorganic like plastic sound much better to use.

Stan