Quote:
Originally Posted by rotorwrench
Wood is very good for structures that are well braced and connected to frame members that hold things in check. If a wood body sets for a long time with no major structural support to keep things is check, things can possibly warp and especially if it sets on uneven surfaces. I'm not saying that is what happened but it certainly could be a possibility depending on humidity conditions and such. Wood can still deteriorate under certain conditions. The Murray and Briggs bodies have a lot of wood structure so that is something to think about.
I have some experience with wood structure helicopter blades. If the helicopter set outside over night where dew and moisture in the air had an affect, it would take 45 minutes to an hour of running the next day to get the rotor system to fly right. If the helicopter was stored in a climate controlled environment over night, it was still as smooth as it was supposed to be. The main rotor blades were tied down to the tail boom when stored outside. The low blade over the tail boom would be heavier the next day due to the dew that had run down to the tip of that low blade overnight. They would slowly dry out when turning the blades at speed. The blades had cloth covering over the wood but it didn't matter. It would still react this way.
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Sounds like a Bell 47? Must have been a very bumpy lateral until all the moisture dissipated and allowed the rotor blades to track properly...
Performed many T/B on Bell's over the years.