Sweet deal! Thanks! I'm starting the design process on my L3 now - its based on a Mongoose 98 minimum diameter and would prefer to fly it on the M3400 over the M2505 if possible... could you send me the thrust curve as well?
I'm also planning on flying it on the P98 6GXL but am not wanting to break the waiver on my cert flight so it'll likely follow.

Thanks, Sean S

A mongoose 98 on an M3400?

That should be awesome - my current design will go quite high (5" fairly light, simming to ~18k on the 3400), but a MD 4 inch should be spectacular. When do you plan to fly it?

That's gotta be a Black Rock shot, right Sean? I'm planning to go to one of the BR launches myself next year, though BALLS may be tough due to so many other diversions that time of year (Oktoberfest, hunting, etc.)

I wonder if a perfectly tuned 4" minimum diameter rocket can beat a perfectly tuned 3" diameter rocket for net altitude? I don't think so... I think an N1100 would easily be the motor of choice on the 98mm side. The 75mm KBA M1450 would give it a run for the money. The Pro75 Dual Thrust motor for that casing would probably tack another 5-8K onto things - possibly more.

I never really thought of this until Dr. J talked about it, but I really believe the highest, single-staged rocket you could build today would fly on a 75mm casing in a min-dia rocket...

I doubt it. What about a 4" MD on a Pro98-6xl 75% or greater N motor?

I would guess that a 3" would be the best for an M, but the extra impulse of the N should more than make up for the additional drag. It's definitely an interesting question though.

Chris, I think you are right. Excluding the 6GXL (which I forgot), I don't think the Pro98-6G or RMS98/15360 hold enough propellant given the frontal area of the 4" motor. The 6GXL might work. What we really need is a 6GXL moonburner....

Just some numbers for the 98-6G casing
N1100 altitude record ~ 45 kft
N3180 altitude record ~ 40 kft

The M1450 in AMW75/7600 casing is capable of 40kft.+. A dual-thrust motor for that casing and some higher density propellant should be 5kft more, at least, as suggested by John. I'm working on a Pro75-like commercial program right now. Within that program, we developed a mold for a larger nozzle. Such a nozzle would really work well with this motor.

An N4100 (98-6GXL) sims to 60kft. I think the N2900 (the Classic load) might result in a few more kft.

Jeroen

I to am very interested in the 'bang for the buck' that 75mm gives you in terms of altitude. I also love the long burns. I guess what I'm saying is that if CTI had a moon burner, or big dual thrust 75mm, (i.e P75-6GXL) I'd be the first in line to buy one. (assuming I had a job by then)

Definitely. A dual thrust Imax similar to the M1300 I flew, but with an extra grain or two would be one heck of an altitude motor. An Imax moonburner could be interesting too...

Great discussion! I say we sort this out a bit east of Gerlach, NV next summer???

Jeroen - any chance there'd be a 9KNS 75mm motor in production by then?

JW3DR

I to am very interested in the 'bang for the buck' that 75mm gives you in terms of altitude. I also love the long burns. I guess what I'm saying is that if CTI had a moon burner, or big dual thrust 75mm, (i.e P75-6GXL) I'd be the first in line to buy one. (assuming I had a job by then)

These are in the planning stage right now. We will probably (?) have some slow winter months during which there will be time to develop this. The same casing/motor would be the 9kNs motor that JW is asking about.

Jeroen

It looks like we have our new contest - the USSS - Uber Single Shot Sweepstakes.

Highest altitude, one shot, 6 grain 75mm CTI motor.

$1 to enter and the winner takes the pot. Can be flown anywhere in the US in 2010. Must have photos of the construction / design / flight posted on the net somewhere.

To run a good contest, raise the entry and we'll probably need some sort of recovery rules and/or time limits from lift off to flight line return. Gee, now I need to build another rocket.

Any chance we can get a higher waiver for MHM '10? .... say 50k? I'm designing the Mongoose 98 for my L3 but also for the 98 6GXL - and since we had a successful staging on our recent trip to Black Rock we're hypothesizing a 3 stage Mongoose 98 - 75 - 54 Definitely Black Rock Material. -Sean

Sweet deal! Thanks! I'm starting the design process on my L3 now - its based on a Mongoose 98 minimum diameter and would prefer to fly it on the M3400 over the M2505 if possible... could you send me the thrust curve as well?
I'm also planning on flying it on the P98 6GXL but am not wanting to break the waiver on my cert flight so it'll likely follow.

Sean, We fired the motors for the M3400 certification this weekend. Everything went quite well. I expect CAR to announce it in a week or two. I don't have your email address. Chris has the thrust curve, he can email it to you.

We also fired a 'monster reload' for the 6GXL succesfully. If CAR signs of on it (don't see why not), we have a cool N5700 for you.

Jeroen

Highest altitude, one shot, 6 grain 75mm CTI motor.
$1 to enter and the winner takes the pot. Can be flown anywhere in the US in 2010. Must have photos of the construction / design / flight posted on the net somewhere.

I think that is a super idea!

Maybe we should have 5 competitions: highest altitude for each available motor size (29/38/54/75/98 ) for the 2010 season on any CTI motor (single stage flight, to keep it simple?).

We could contribute some interesting prices.

Jeroen

NOW we're talkin'! That'd be a fun contest...