Kosdon 3" 10,000 ns or N Motor?

Okay, I totally dig Kosdon stuff and have a decent recollection of his more exotic designs like the 54mm L-3000, 4" O-10,000, that 29mm J something or other; for example. However, here and there I've read about 3" N motor or a 3" 10,000 ns casing. I guess I must have totally missed this animal over the years but I'm dying to know more. Anybody know what the story is on this like what kind of reloads were available, the casing length, and any other bits of information that a Kosdon motor geek would like to know???? I'd probably pass out if I saw pictures . Thanks in advance!

There was a M3400 Slow and a M5100 Fast for that casing according to the price list I have from Kosdon.

A while ago I spent some time and effort, for historical purposes, to round up as much Kosdon data as I could to create motor files. I messaged a bunch with Jim Rosson, and he never mentioned anything about this.

Frank had some cases that never had a certified load for them. Also, some were very low volume i.e. the 2.5" cases- Jim told me that there were only a few of them made.

I cannot confirm the motor you mention, but it would not surprise me to learn of something like this.

I burned a 2.5" L1600 in a 25# 6 X RAMJET, took off like a scalded cat. I borrowed the case and paid for the fuel. It was sure something

nraymondb said:

There was a M3400 Slow and a M5100 Fast for that casing according to the price list I have from Kosdon.

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Thanks for the tip. A 3" nearly full M-5100 sounds like a mean motor. Just dug this up on Derek's site:



Too cool!

pyrobob said:

Thanks for the tip. A 3" nearly full M-5100 sounds like a mean motor. Just dug this up on Derek's site:

Too cool!

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That's what I was going to post.

Steve Heller flew a Kosdon 10k on Saturday with an EX load.

Anybody know if Kosdon's reloads had inhibited grains, differing core diameters (I would imagine so), etc.?

Kosdon motors rocked. Helped move rocketry to FG as they had a bad habit of shreding card board rocket kits.

pyrobob said:

Anybody know if Kosdon's reloads had inhibited grains, differing core diameters (I would imagine so), etc.?

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I think some of them had different core diameters. I remember seeing a Kosdon motor with the grains numbered so you got them in the right order for just this reason.

Many of the longer Kosdon motors used stepped cores and AMW did the same as well in their longer motors. AMW did a great job in their instructions making sure the person assembling the motors put them in the correct order.

Preston

markkoelsch said:

I think some of them had different core diameters.

I remember seeing a Kosdon motor with the grains numbered so you got them in the right order for just this reason.

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Kosdon East had a N3400 green gorilla and a M4000 skidmark for the case as well. The M3400 has four slow grains bottom two inhibited. The M5100 was four grains , bottom two fast inhibited, 1.188 cores ,inhibited on one end. top two grains slow 1 inch cores.

I would bet a MD M5100 would be as challenging as a MD N5800

Some years ago, I've met an Italian rocketeer at a launch in Germany. He had a nice carbon fiber 75mm minimum diameter rocket with him. He mentioned that he intended to launch it on a 75mm Kosdon N. Never having heard of a 75mm N before, I asked if he meant an M and he confirmed that he was talking about an 75mm N. Unfortunately, I don't have any further information. I don't have met the guy again, either.

Reinhard

The M5100 was four grains , bottom two fast inhibited, 1.188 cores ,inhibited on one end. top two grains slow 1 inch cores.

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Eric,

I know nothing about the M5100, but knowing what I know about motor design, I would more likely believe that the fast propellant was at the head end and the slow at the bottom end. Otherwise, having fast propellant at the bottom in an already erosive motor would cause the bottom to burn out even faster, leaving the top end to tail off for some time after the bottom burned out, leaving you with a longer burn time and far less average thrust than 5100Ns.

For a very long time I have wanted to scale up my own 54/4000 to the 76mm N size, and I have even planned out a shippable 98mm ~50% O.
Kosdon for sure set a high bar that I have long been wanting to hurdle. I just need the business to grow more in order to fund these.

Scott you are completely correct. I had a brain fart , or two many beers? All grains are fast in the 5100. I was still thinking about the 3400 top end.

Got one of these cases sitting around....how much of a collectors item is it?????

I flew this case last week with my own load. I'd post pictures but I'm on my phone - check the Verrukt thread in the HPR forum.

I was playing pickup basketball with some college friends of mine in Goldsboro, NC in October of 2010 when the three of us walked across the street to Ken Allen's house. Ken had a shed overflowing with vintage stuff and gave me a deal I couldn't refuse on a Kosdon 3" 10k case. The next month, I made a 10 grain low solids load for it and flew it in Mike Harris's Standard ARM at Bayboro, NC. It was awesome and one of the cooler successes of my early motor making career. It then moved from apartment to apartment, state to state with me as I moved on to composite cases until last week, when I needed a cool Black Rock project I could whip up in a week and it was there staring at me. Kosdon made the load with two fast grains up top and two inhibited slow grains on the bottom with a 1.25" core and a 1.25" nozzle. The proportionally identical L3000 and O10000 were made the same way.

Two different propellants is the right way to counteract erosivity in this motor, but I only had time for one mix so I just made the grains gradually increase in length as they neared the nozzle end. This time did 4 grains with 1.25" core on the top 3 and 1.375" on the bottom grain with a 1.175" nozzle and lit it in the middle of grain 3 to soften the erosive spike at startup, as I did on the first motor. Check the Verrukt thread for pictures and video, but took my fincan to 33k in the mid M3 range. Cool little motor, fun for a project when the time is right. It'll probably be another 5 years before I make another load for it, but when the time comes, it'll be sitting there.

Steve Heller
Houston, TX

What's the TPL of this motor?

51.75

pyrobob said:

Okay, I totally dig Kosdon stuff and have a decent recollection of his more exotic designs like the 54mm L-3000, 4" O-10,000, that 29mm J something or other; for example. However, here and there I've read about 3" N motor or a 3" 10,000 ns casing. I guess I must have totally missed this animal over the years but I'm dying to know more. Anybody know what the story is on this like what kind of reloads were available, the casing length, and any other bits of information that a Kosdon motor geek would like to know???? I'd probably pass out if I saw pictures . Thanks in advance!

Click to expand...

I'm 8 years late to this party.

I have the complete hardware that you mention, and I may also have a load. I don't know if you ever wanted to buy this or were posting for information only.

My personal email address is attached.
Removed

I very much miss Frank. We've had some fun times together.
Jim

ZEDL1 said:

I'm 8 years late to this party.

I have the complete hardware that you mention, and I may also have a load. I don't know if you ever wanted to buy this or were posting for information only.

My personal email address is attached.
Removed

I very much miss Frank. We've had some fun times together.
Jim

Click to expand...

Send your email to him by conversation or PM. Removed to avoid spambots.