HAS ANYBODY HERE FLOWN A KOSDON 29MM J1000?

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One of my favorite urban legends involves this motor. I heard it second or third hand, so who knows if it's really true. Story is that Frank fired this motor and of course it sounds like a gunshot. While walking around the pad afterward somebody finds a 29mm Kosdon grain just sitting on the playa. Frank looks at it and it matches the length and core on the 29mm. The nozzle throat on this motor is pretty huge, but extruding a grain through it in one piece is pretty insane. Out of curiousity, they numbered the grains and fired the motor again. Sure enough, they later found grain #1 on the playa... intact.

Todd Harrison
And people wonder why I've never had the guts to fire it! It's all over in .4 secs (Not 4 secs- that's .4...shotgun indeed!)
 
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And people wonder why I've never had the guts to fire it! It's all over in .4 secs (Not 4 secs- that's .4...shotgun indeed!)

[video=youtube;T437DdmFNPU]https://www.youtube.com/watch?v=T437DdmFNPU[/video]
 
There was another Kosdon motor called "The Safecracker", it was either the 54mm or 2.5" max length fast. When fire someone said "It's dynamite. You could bust a safe open with it!"

I did a few 0.2 second small J motors. They wrecked every rocket they where launched in.

M
 
Can we see the pics of this thing?

Case length would be great, grain geometry even better. Notes about inhibitors on the ends of grains would be the best.

Frank's formulas are out there now. We have the technology...
 
Can we see the pics of this thing?

Snipped ..

I don't have any. We did not take pictures or write things down. We made rockets.
Very little of Frank's info was written down, even for production items, until he made the Aerotech deal. The non production motors are likely never recorded.
For my fast J's they used a lot of 15 micron to get the burn rate.
I have made O and P motor rockets that I don't have a photo of.

M
 
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Pretty sure there's a thread or blog where someone documented the L3000 showing the inhibited grains. It's about as close as I've been to flying one unfortunately :cry:.
 
Pretty sure there's a thread or blog where someone documented the L3000 showing the inhibited grains. It's about as close as I've been to flying one unfortunately :cry:.

Right, that's what I'd like for this 29mm J motor that's being teased. Fyrwrkz says he has a case and several loads, it would be great to document them.
 
I don't have any. We did not take pictures or write things down. We made rockets.
Very little of Frank's info was written down, even for production items, until he made the Aerotech deal. The non production motors are likely never recorded.
For my fast J's they used a lot of 15 micron to get the burn rate.
I have made O and P motor rockets that I don't have a photo of.

M

And that's fine.

I'm specifically asking fyrwrkz to document what he has on hand. Doesn't matter if Frank documented them then, we can document them now!
 
Pyrobob said:
Pretty sure there's a thread or blog where someone documented the L3000 showing the inhibited grains.

Do you mean this one?
https://www.here-and-beyond.com/Projects/KosdonL3000/Disassembly/IMG_5625_resize.htm
I've often wondered if the intention of the poly donuts was to add a layer of cool gas over the nozzle surface, helping to keep it from getting too hot for certification approval, and possibly to decrease erosion of the bottom grain. I can see where inhibiting one end of the bottom grains changes the motor geometry, but those look to be much thicker than what would be needed for simple grain face inhibiting.

One of the reasons I switched to a single use phenolic/graphite composite nozzle for my reloads designed for this case was that just about every new graphite nozzle I fired a load in was cracked in half after the first firing. I am told had similar issues, but maybe not as bad. I'm not sure if this is from thermal shock, resonance or a combination of these or something else.

Mark, can you shed some light here on the reason/s behind the poly donuts?
 
Okay guys-this may take a bit. my computer is so old there are no usable USB ports for my camera. And I lost my phone (camera) at the ROC launch last summer. I know.. I'm an idiot....maybe KenRico can help out.
 
Okay guys-this may take a bit. my computer is so old there are no usable USB ports for my camera. And I lost my phone (camera) at the ROC launch last summer. I know.. I'm an idiot....maybe KenRico can help out.

Sorry for badgering you here and via PM...as has been expressed in the thread this is a relatively rare and "legendary" motor. It's likely not a J motor nor is it some super efficient marvel of engineering, but it is nostalgic and will be fun to see. The only way more will be made is through cloning from your pictures/information.

Pictures would be cool, but data would be even cooler. Any chance you can provide the following grain information?

Grain #; Grain Length; Casting Tube OD and ID; Grain Core Diameter; Inhibitor thickness

Also, if you can get a nozzle throat that would be awesome. I now have the means to make such a casing and may be interested in cloning these for people if there is an interest. If that's the case (no pun intended), I'll likely need a Kosdon 29mm bulkhead to clone. Maybe I'll give Kenny a call.

Thanks!
 
Dan- no badgering at all, brother-it's a weird motor to begin with. I'd love some 'milder' mixes for it anyway. Back in the day, I paid for a carbon motor tube before they got so cheap, but never had the airframe for it. I'll dig it out (it's been buried for a loonngg time!) and get some specs on it. It was an 'impulse' buy-(pun intended!) but just never got around to it. The only reason I thought about it was Springfest and the EX motor day, but again, I couldn't make the deadline to get a bird together.
 
Well you know where to go if you want to sell them. Only need to figure out Hazmat...
 
Flew a Kosdon I500 once. Or I should say it flew,the rocket stayed on the pad. lol
 
Friendly bump :)

It's so close, yet so far away! If we get the information and someone is interested in a clone of the motor, I will order the tubing and get to cloning the case. Casing, bulkhead, nozzle, nozzle washer, and o-rings for $100. $105 with an external ring.

If you're interested, let me know (after we get the info)!
 
One of my favorite urban legends involves this motor. I heard it second or third hand, so who knows if it's really true. Story is that Frank fired this motor and of course it sounds like a gunshot. While walking around the pad afterward somebody finds a 29mm Kosdon grain just sitting on the playa. Frank looks at it and it matches the length and core on the 29mm. The nozzle throat on this motor is pretty huge, but extruding a grain through it in one piece is pretty insane. Out of curiousity, they numbered the grains and fired the motor again. Sure enough, they later found grain #1 on the playa... intact.

Todd Harrison

I was hanging out with Frank and Ken on the Eldorado (or Lucerne?) Playa at LDRS in 2001 and Frank showed me this 29mm case that was some 3ft long.
He asked me if I was man enough to fly that thing...:y:

John
 
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Were you????
Inquiring minds want to know ;)

JD

I was hanging out with Frank and Ken on the Eldorado (or Lucerne?) Playa at LDRS in 2001 and Frank showed me this 29mm case that was some 3ft long.
He asked me if I was man enough to fly that thing...:y:

John
 
Dan, you and I must be on the same wave length... While reading the newspaper this morning something triggered in my mind the beastly 29mm x 36" long Kosdon motor. Specifically, I was wondering about the number of grains and their geometry. Can hardly wait to set my eyes on this motor!
 
Well, I'm holding off on buying any more 29mm casing stock because I would need to order from a different supplier for the 3 ft. length. Right now I buy from Amazon (free shipping) for a pretty good price at 2 ft. lengths, but I'd need 4 ft. lengths to make these bad boys. If we get the info and someone wants one, I'd start ordering materials to make them up for you guys.
 
Well, I'm holding off on buying any more 29mm casing stock because I would need to order from a different supplier for the 3 ft. length. Right now I buy from Amazon (free shipping) for a pretty good price at 2 ft. lengths, but I'd need 4 ft. lengths to make these bad boys. If we get the info and someone wants one, I'd start ordering materials to make them up for you guys.
I swear Dan, I will dig that puppy out this weekend and get KenRico to help me post pics. This thing is five footlockers and 4 totes down in a ridiculously crowded garage. (the loads are inside-under the baby's crib-nice and safe!)
 
29mm I800...

kosdon.jpg


Tony
 
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