Ye Olde Rocket Forum - View Single Post - Estes Saturn V Build

Quote:

Originally Posted by DaveR

Having never built a Sat V, I thought your measurement on how much the motor mount was to be recessed was a typo, but after reading further, I see that's not the case. 3 3/8" seems like a lot to me. At what point does the Krushnic effect come into play?

I would hopefully always launch this rocket with enough of a stand-off from the blast plate to not allow a vacuum build-up, which I think is what causes the Krushnic effect with recessed motor mounts, although I've never seen it happen and am not all that familiar with it.

What I am really concerned about is just the burning of the inner lining of the main BT from the RMS motor exhaust. If I recess the mount just a little less I think I can reduce the possibility of that inner burning. Actually I see it a lot on one of my TLP kits, where the mount is recessed and the engine exhaust has charred the inside of the BT.