Guys,
There are as many options to do it as there are opinions. I have a fleet of nitro riggers (and one mono) and have used the same method for over 12 years. Rarely do I break a shaft or bend the tubing. Here is what I d use. There are two long brass tubes used. One is 1/8" larger than the shaft itself and that is for the strut tube. Then the next size up is used for the stuffing tube that is glued permanently into the hull. The strut tube fits tightly into the stuffing tube. Then I use, as shaft bushings (instead of shaft bearings), a brass tubing that fits tightly over the shaft and fits into the strut tube. Therefore you actually need 3 sizes of brass tubing, all that fit into each other. I do not use telfon strut tube liners. This is the method that Andy and John Brown uses and has been the way Roadrunners have always been initially set up. However, I do not believe that any specific way is the right and only way. Comes down to personal preference in the end.
Most racers use 3/16" (.187) shafts for 20's and 40's. Then use 1/4" (.250) for 60's, 80's, 90's & 100's. Some use 3/16 for 60's but I have seen a number of broken or twisted shafts from it. In my opinion, 1/4" for a 40 is overkill, not needed, and adds excess weight. Besides, a 3/16' shaft can spin a faster revolution than a 1/4" generally speaking. Have seen some 10's and 20's use 1/8" (.150) shafts as well. I never use one that small as the rpm's on the 20's are too high for racing. I have no confidence level with that small a shaft.
John
