Rocketry Planet

We are very pleased to announce new motor certifications from two manufacturers.  At the final test session prior to the start of LDRS week, held on the 20th of June, we certified four new motors, one from Gorilla Motors, three from Loki Research.

From Gorilla, we have certified the first of two new loads for his 75-3500 case.

The L425WC-PS is a 31% L, in a Moon-Burner geometry with Jim Harris's very smooth, aluminized propellant.  The Thrust profile is an immediate rise to 173 pounds, dropping to 135 lbs, with a flat line to the 2 second point, then a straight line to 0 at the 8 second point.

Total Impulse  3372 Total NS (32% L)
Max Thrust 172.96
Average Thrust 424.18 Average
Burn Time 7.95 seconds
Propellant Weight  1837 g
Total Weight 3742 g

Loki Research is continuing its return to the certification process with a vengeance.

First off is the final sparky motor of the first half of the year, the G69SF-17A.  This motor is not your typical G Sparky as it uses Jeff's LifeSaver style 1X1 grain geometry, utilizing two of these grains in his 38-120 NS case for a 33% G.

Total Impulse  106.1 (33% G)
Max Thrust  99.6
Average Thrust 87.17
Burn Time  1.589 sec
Propellant Weight  63 g
Total Weight  239 g

Next up is the first of a set of two monster motors.   The M3000LW-PS is Jeff's first certified motor in his unique 75-8000 snap-ring case.   This 74% M motor starts with a 1050 lb rise at start, with a regress to 850 lbs at the .5 second point.  This motor then has a slight rise from that point to 875 lbs at 1.2 seconds. The curve returns on a straight line to zero at the 3 second point

Total Impulse  8924.3 NS (74% M)
Max Thrust   4752.19 N
Average Thrust  2920.9 N
Burn Time  3.059
Propellant Weight  4350 g
Total Weight  7166.7 g

Last but by no means least, is the second biggest motor we've tested in the past few years.  The N3800LW-PS motor is a 25.6 pound (11611 g) motor in Jeff's new 98-12500 (4" X 41") case.  Many will be familiar with this motor as it was the "N's" in the April Saturn V launch by Steve Eves.   This motor ignites to 1000 lbs, with a short flatline at that point to .7 second point, where it then progressively rises to the max point of 1120 lbs at the 1.5 second point, then pretty much a straight drop to zero at the 3.248 second point, with a "knuckle" at the 600 pound point at 2.84 seconds.

Total Impulse  12490.28 NS
Max Thrust  5148 N
Average Thrust   3850.82
Burn Time  3.249
Propellant Weight  6124 g
Total Weight  11611 g
 
We wish great success to both manufacturer's and congratulate them on these new motors.

Our next test session is preliminarily scheduled for the first part of September as it is HOT here in Texas right now and the test field crop of corn is drying out fast.!

H. Paul Holmes
Chairman, Tripoli Motor Testing

Reader comments:

#1 Re: Article: TMT announces new motor certifications for Loki, Gorilla

Awesome

Another sparky G motor, I might just have to check this one out.

Donaldsrockets on 06-25-2009 12:38 PM

#2 Re: Article: TMT announces new motor certifications for Loki, Gorilla

Quote:

Another sparky G motor, I might just have to check this one out.

Yeah, and without certification drama either.

ddmobley on 06-25-2009 12:43 PM

#3 Re: Article: TMT announces new motor certifications for Loki, Gorilla

What makes you think there was no drama?

The current rules where a motor can fall in between "model rocket motor" and "high power model rocket motor" are a bit silly in my opinion. The Loki G motor initially had this problem. It wasn't a "high power" motor because the propellant weight was under 62.5g and the average thrust was under 81Ns. It wasn't a "model rocket motor" because it emits sparks. To get it certified, I had to add propellant to get the weight up to 63g. If ATF permits were still required, I'd be screaming, but since ATF worries are gone, it doesn't matter so much.

Loki on 06-25-2009 01:13 PM

#4 Re: Article: TMT announces new motor certifications for Loki, Gorilla

Quote:

What makes you think there was no drama?

My bad! I guess I was projecting hopefulness.

Quote:

The current rules where a motor can fall in between "model rocket motor" and "high power model rocket motor" are a bit silly in my opinion. The Loki G motor initially had this problem. It wasn't a "high power" motor because the propellant weight was under 62.5g and the average thrust was under 81Ns. It wasn't a "model rocket motor" because it emits sparks. To get it certified, I had to add propellant to get the weight up to 63g. If ATF permits were still required, I'd be screaming, but since ATF worries are gone, it doesn't matter so much.

I agree. It is a no-man's land where there are no defined rules to follow.

Unlike when a motor's certification has expired. A while ago.

And we recertify them ... based ... on ... what? Rules?

ddmobley on 06-25-2009 02:58 PM

#5 Re: Article: TMT announces new motor certifications for Loki, Gorilla

I've forgotten all the details from the previous time this arose, but why is the sparkiness of a motor treated differently than, say, the under 62.5g G motors with average impulse over 80 NS?

rstaff3 on 06-25-2009 03:14 PM

#6 Re: Article: TMT announces new motor certifications for Loki, Gorilla

NFPA sets the rules to what is a model rocket motor and what is a high power rocket motor. The other motor (CTI G69 Sparky) didn't meet any of the requirements to be a high power motor but it produced sparks and NFPA says that a model rocket motor can't produce sparks. This puts the motor in limbo between high power and model. To fix this, you add propellant mass to bump it past the minimum for a high power motor (like the AT G75 or G33)

NFPA should be fixed to correct this. I think they should remove the sparky part of the limitation to a model rocket motor but I could also agree to a "catch-all" that promotes motors that don't meet the model rocket motor limits to be treated as high power motors similar to G hybrids.

-Aaron

heada on 06-25-2009 03:34 PM

#7 Re: Article: TMT announces new motor certifications for Loki, Gorilla

Thanks for the response. That should have been obvious. Now, where the heck are my car keys?

rstaff3 on 06-25-2009 05:21 PM

#8 Re: Article: TMT announces new motor certifications for Loki, Gorilla

Quote:

Now, where the heck are my car keys?

Your life must be like mine.

SecretSquirrel on 06-25-2009 05:30 PM

#9 Re: Article: TMT announces new motor certifications for Loki, Gorilla

LDRS is gonna be wild! There are so many new motors! I'm pumped, I leave for NY on Monday morning, right after a couple days of launching at our home launch here in Lethbridge, Alberta

Dipstick on 06-26-2009 02:00 AM

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