04-04-2011, 10:00 PM
|
 |
Flying since 1977
|
|
Join Date: Oct 2010
Location: Middle TN
Posts: 455
|
|
Quote:
|
Originally Posted by Earl
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.
|
The Krushnic Effect is definitely real. I had an Estes Hercules that kicked the booster motor without kicking off the booster airframe. The A8-5 burnt out the booster motor tube, but the sustainer did not gain much altitude after staging. For this flight, the sustainer motor acted like a delay train, instead of taking the upper stage to the significantly higher altitude that it would have reached if everything had worked normally.  I suspect that if I had used a B or C motor instead of an A8-5, the booster airframe (BT-50) might have been burnt away as well.
__________________
'Til next time,
Mike Toelle
NAR 31692 L1
SAM 0373
|