I got one of the new ones and the only difference I noticed is the shaft threads are different than my old one. My tru turn spinner adapter will not fit the new one. Have not flown the new one yet but on the bench (after considerable break in per instructions) it turns the exact same prop at the exact same RPMs as the old one. My "old one" is the second generation.
Hi Chris,
On my engine the furnished prop nut would only thread onto the shaft a short way nor would other 1/4-28 nuts do any better. Clearly the shaft threads weren't cut completely. I contacted Brodak about it and he checked the engines remaining on hand and discovered they were all that way. He then re-threaded the shafts of the remaining engines and forwarded one to me along with a prepaid return label allowing me to return it at no personal expense. I expect a call to John would get you the same offer.
By the way, maybe everyone else knows this but I was also unable to thread the provided nut onto the long threaded shaft that secures the front and rear halves of the muffler together. As with the crankshaft I was able to get the threads started but, even with what I felt was excessive torque, was never able to get the shaft completely through the nut. I encountered the same problem with the muffler assembly with the second, replacement, engine. Fearing a reprise of the crankshaft threading problem I sent both muffler shafts back when I returned the original engine explaining my concern.
One of John's employees responded to my email on the subject advising the nuts for the muffler shaft are "lock" nuts and require extra torque to install; further advising both units I returned were normal examples. FYI, These are not lock nuts such as the ones we're used to seeing stateside with the synthetic locking material in a "bulged" backside of the nuts but, instead, appeared to have been "crimped" on the "back side" perhaps distorting the threads so that they are difficult to install/remove. Since this is my first Brodak .40 I've no idea whether the muffler assembly or the unit itself differs from earlier manufacturing lots.
I had hoped there would have been some mention of this unique "shaft/nut" assembly in the instructions and just reread them to determine if I'd missed a note about it. Unfortunately, there is no mention of the assembly procedure for the muffler. If you hear anyone having a similar problem point this out to them. I haven't received my muffler shaft/nut back from Brodak yet but my memory tells me you can see the difference between the front and back side of the nut via the obvious tiny distortion to the back side of the nut. The shaft would not thread into that side but would thread a turn or two from the other side before encountering resistance from the "crimp". Note that my experience was that I was unwilling to apply enough torque to overcome the resistance so you might also find yourselves having to apply a bit more than is generally comfortable with a small machine screw (it is approximately the size of an American 4-40 but I didn't attempt to thread a 4-40 nut onto the shaft...again, thinking it might have been a problem similar to the crankshaft.
Please note that my use of the word "crimp" is strictly a means of making the point and is not a word used by anyone at Brodak in my correspondence with them. There is, no doubt, a technically correct term identifying this type of secure fastener.
Ted Fancher
Topic: Brodak 40 (Read 2411 times)