Until now, I'd never even heard of the Krushnik Effect.

Are you making this up?

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Never trust an atom. They make up everything.

4 out of 3 people struggle with math.

Chemically, alcohol IS a solution.

NAR# 94042
SAM# 0078

Great reading rocketguy, and beautiful Centuri Sat V!

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I plan ahead that way I don't have to do anything right now.

Oh by the way, I'm not here just for the "olde" rocket discussions.

chk pg 37 of the Nov 69 Model Rocketry (pg 39 of the pdf)

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David Stribling
NAR 18402 SR
But it is rocket science!
Get yer Barrowmans here

Thanks! Keep us posted on your build, I am really curious as to how different the new Estes model is to the Centuri version.

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David Stribling
NAR 18402 SR
But it is rocket science!
Get yer Barrowmans here

Thanks Randy. I think if I recess it 2 1/4" it should eliminate any serious interior burning.

I built the Sat V kit 2001 a few years back and I set that one up with a trippe 24mm mount, also recessed to 2 1/4" and that one has flown with no interior burning so I think that's probably a good compromise placement. I've never launched that 2001 version with an RMS motor though...

__________________
I plan ahead that way I don't have to do anything right now.

Oh by the way, I'm not here just for the "olde" rocket discussions.

Will do rocketguy!. I'm hoping to make some good progress on it this week, as long as I can pickup the adhesives I need.

__________________
I plan ahead that way I don't have to do anything right now.

Oh by the way, I'm not here just for the "olde" rocket discussions.

My son built his first run 2157 kit and had issues with the third stage wrap. He printed off a new paper shroud with the correct dimensions to match the wrap. The original Centuri kit had much thinner plastic wraps and the body tubes are just a hair different from Estes. That combination seems to have made a considerable difference.

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I love sanding.

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.

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'Til next time,

Mike Toelle

NAR 31692 L1

SAM 0373

[QUOTE=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.

Sounds right.

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

I think it's not talked about too much because 99% of the rockets being flown all have the engines at or below the bottom of the bt. I have only seen it happen once to another flyer who set his rocket about a half inch off the blast plate. It didn't go anywhere and burned about 75% of the rocket before it was extinguished.

Randy
www.vernarockets.com

The first time I heard that term used, I thought they were talking about the Russians pranging a satellite launcher...


Bill