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 seem to recall a very general rule of thumb on preventing the Krushnic effect by recessing the motor (i.e., specifically the exit plane of the nozzle) to NO MORE THAN one body diameter. In the case of the Saturn V, that'd be just about 4 inches, so a 3 and 3/8", it would seem by that general rule you'd be ok.

Anyone else confirm this general rule? You don't hear folk talk much about the ol' Krushnic effect anymore.

Earl