Hi,

You guys would never have gotten to the moon....

Seriously, on the end grain balsa.
There is a guy running a DA150 on it. He also says he ran a DA85 single on it. If it can take a single, I think it should be pretty good for what ever I can throw at it.. Apparently the key is to toughen it up with thin CA and cap the engine side with thin ply. I have done this to a hollowed out block and it is lighter than the aluminum standoffs. Will be interesting to see how it works in practice.

On the 4-40s.
When I was flying a lot years ago, I used 6-32s to hold 100cc motors on. Had no issues after many hundreds of flights.
I've run many 100cc motors on the test bench on 4-40s with no problems. Would they hold up to the gyroscopic loads of aerobatics and 3D? I don't know, so I'll wait for some other super genius to figure it out.

Soar,
Why would a ply box be quieter?

Alt and TOM,
Thanks for the links.

p.s. Got a nice present in the mail today. See pic.
The things are so pretty I feel like mounting them on the side of the plane like the pipes on old Corvettes.

Branwell