Ellis Mountain

I have been doing some archival work while enjoying "social distancing", and my attention has been drawn to the www.thrustcurve.org and TMT archival data at my disposal for Ellis Mountain. I realize that they (he) has not produced any motors in several years, but several aspects are interesting. The archival data do not describe any designation that would indicate that EM produced more than one propellant type. Can anybody confirm that, and, if so, what was that propellant? I notice that the burn times were unusually long compared to other motors from other manufacturers, and the average impulse figures were very low. Does anybody have any real information about the nature of his propellant?
p.s. I am finishing up a project that will combine and cross-check every data-base of certified hobby rocket motors. This project was begun in an effort to comply with NFPA 1125 section 8.3: Listing of Certified High-Power Rocket Motors and Motor-Reloading Kits. Lots of work in the dusty old archives of the interweb, but the end result is coming soon. Stay tuned.

Alan Whitmore
Chair, TMT

I know he also had a blue propellant; the K600 single use motor used it.

I've flown Ellis motors. He did have only 1 type of propellant that I know of. Think my 68-10 but with a good amount of larger AP particles. I don't know if he used a burn rate inhibitor.
Will be looking forward the the motor data

If I remember correctly, Ellis advertised a "Thors Hammer propellant", slow burning. That was back in 2002-2003 approx. That's the only thing I ever saw listed.

Roy

Robert Ellis had two propellant formulas, regular and fast. I don't know how many he had certified with the fast. He also had another very fast propellant being tested as a G4 glider motor. (I visited his shop often from 2004-2006 when I lived 20 miles from "Ellis Mountain".)
Most of the variation in the motors were done though grain design using the same propellant.
Ellis also made Aerotech propellant under contract after the AT Vegas fire.

I have a couple of J330 Thors Hammer reloads that were gifted to me with a case. I plan to use this summer.

I also visited Bob in his shop before he passed, and I even have his propellant mix sheets. He had two main propellants - Thors Hammer and Thors Hammer Fast. Thor's hammer was the one he used most often. He used oxamide as a burn rate suppressant to help get his slow burn rate. He also had at least one other that was used for military contracts he had that was never certified for consumer use.

He was a very interesting guy, I wish I had interviewed him on tape. While mixing and casting propellant he'd tell stories of his time in the military. He had been a navy SEAL in Vietnam and while he never went into great detail, it was clear he saw and did some very dangerous things. He was a big guy and had one speed - amble. I still have a fair number of his 29mm H50 and H101 motors which are really great performers. (Although they now have to be flown under research rules.)

I think he was unfairly tagged after the Aerotech fire when he made propellant for them and it had issues due to the very different environmental conditions he operated under. He lost a lot of money when AT declared bankruptcy and never really recovered from it, which just added insult to injury. He also really pushed the edge of very high L/D motors, and they could be temperamental, especially if you didn't follow the instructions on ignitor placement.

Bob was also a very good machinist. He'd be working on something, take a break, and come back after a while with a newly machined part custom made for that task at hand. He just had that mechanical knack for figuring things out. I learned a lot from him and think of him every time I mix propellant and of course when I fly one of his motors.


Tony

I may have some old video. We flew the L-600 i think it was in a few of the old 5.5" kits. Fun motors, and I only remember the 1 propellant type as well. The videos are on a VHS from back in 98-99 ish. Not sure how to even get it copied anymore.

The L600 used the fast version of Thor’s Hammer. Nearly all of his other motors used his regular Thor’s Hammer propellant. Thor's Hammer used oxamide and a high percentage of 400 AP for it's slow burn rate. Thor's Hammer Fast still has 400 AP, but the percentages are pretty much flipped from the regular mix, and of course, no oxamide. Since this isn't the research forum, I'll leave it at that. But he did have two very distinct propellants.


Tony

I loved his long burn motors. Still have a few single use F,G and H motors. But only one J330 reload left.
Sad day when he passed away.
Mike

Alan Whitmore said:

I notice that the burn times were unusually long compared to other motors from other manufacturers...

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I always assumed that most of these were moonburners, is that not the case?

mikec said:

I always assumed that most of these were moonburners, is that not the case?

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No, all the ones I flew are BATES grain motors. His H50 and M1000 are good examples, 5 sec and 7 sec burn times, respectively, but not moon burners. As I posted above, it was his formula that allowed him to get the longer burn times.

Actually I never quite got the name of 'Thor's hammer' for a long burn propellant. Thor's Thunder would maybe have been more appropriate.


Tony

https://web.archive.org/web/20040608121910/https://www.geocities.com/ellismountain/

Tony - the other one

tfish said:

https://web.archive.org/web/20040608121910/https://www.geocities.com/ellismountain/

Tony - the other one

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Man do I LOVE the WayBack Machine!!!

Man, I miss these motors.

manixFan said:

Bob was also a very good machinist. He'd be working on something, take a break, and come back after a while with a newly machined part custom made for that task at hand. He just had that mechanical knack for figuring things out. I learned a lot from him and think of him every time I mix propellant and of course when I fly one of his motors.
Tony

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I have his black anodized 38, 54, and 75 mm cases that he made that now a days use KNSB.

High Desert Rocketry said:

I have his black anodized 38, 54, and 75 mm cases that he made that now a days use KNSB.

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My first L2 cert was on his J330. Nice motor. Still have the casing. Once I recert L2 I think I will take a sugar trip. Should be a good ex casing.

PatD said:

My first L2 cert was on his J330. Nice motor. Still have the casing. Once I recert L2 I think I will take a sugar trip. Should be a good ex casing.

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Used the 75mm many times till I blew out the divergent section of his graphite nozzle at BALLS. Now I use stainless steel that lasts forever with KNSB propellant.

manixFan said:

and I even have his propellant mix sheets.

Tony

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Do you want to share?

manixFan said:

I even have his propellant mix sheets.

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Ditto. That is a piece of his history that should be shared.

Why did no one pick up his long burn motors and start producing them?

I was a big fan of the 54mm SU L330. I think I flew three of them between 2005-2008. They made for some really cool flights in 3" lightweight rockets to 12-14K' at Lucerne.

Got my L1 on a H275. Not sure if that was the "fast" propellant - all I know is the delay was extra long. Should have been 10 seconds and was closer to 14. Was an awesome flight but just about gave me a heart attack. Lawdy did I ever love that propellant but those delays were all a little suspect lol.

Didn't the "11 seconds of terror" story in that originated at one of the Danville, IL launches involve a Ellis Mountain J of some sort?

DAllen said:

Got my L1 on a H275. Not sure if that was the "fast" propellant - all I know is the delay was extra long. Should have been 10 seconds and was closer to 14. Was an awesome flight but just about gave me a heart attack. Lawdy did I ever love that propellant but those delays were all a little suspect lol.

Didn't the "11 seconds of terror" story in that originated at one of the Danville, IL launches involve a Ellis Mountain J of some sort?

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I thought it was an Aerotech I65.

DAllen said:

Got my L1 on a H275. Not sure if that was the "fast" propellant - all I know is the delay was extra long. Should have been 10 seconds and was closer to 14. Was an awesome flight but just about gave me a heart attack. Lawdy did I ever love that propellant but those delays were all a little suspect lol.

Didn't the "11 seconds of terror" story in that originated at one of the Danville, IL launches involve a Ellis Mountain J of some sort?

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The H275 was after the Aerotech fire . They produced motors for Gary . They where basicly single use H220 Blue Thunder motors.

cavecentral said:

I thought it was an Aerotech I65.

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Correct . Never play with ignitors inside motors with the ends not shorted together.