RE: MagnumR Maiden Advice
Two reasons actually......
1) you want the ground rpm on the Q500 engine to peak between 19,500 and 20,000, and launch it around 500-800 down from peak. The 9x6 will sorta be running-on-the-governor from the beginning. Not much load there.
2) yes, i have concerns over the 9x6 structure wise. I have no quams turning one at 17,000 - 18,000 or so. If you are seeing 20K peak rpm on the ground, the engine is going to unload up approaching 22K rpm in the air.
In the end, its up to you. That first launch is important.
Be careful.
If you happen to have any of the "older" style D-1 props, like the 9.25x7 or similar, perhaps try that.