75mm DMS Single-Use Motors

Aerotech just posted this on their Facebook page under motors approved by CalFire:

75mm DMS Single-Use Motors
M1350W-PS (P/N 13135P) White Lightning

Anyone find this interesting?

Yes, I believe this will encourage more to go for there lvl 3.


TA

Yes, to lower the barrier to entry to Level 3; not having to invest in hardware will be a pretty big deal to most people especially if you don't plan to fly Level 3 motors often. I held the casing/nozzle assembly not long ago and it's pretty nice. I'm not sure of the total impulse but it will probably be comparable to the M1297. The price point, like the rest of the DMS line, should be very competitive and will likely push Level 2 guys to reconsider or go ahead with a Level 3 attempt. There are always exceptions, but I presume this is the targeted niche.

Just posted an entry on ThrustCurve.org; now who will be the first to make a thrust curve for it?

I saw this yesterday as well... I'm an avid prowler of their Facebook page and I'm quite sure they haven't made any announcements of this motor (and the H550ST) being certified. Of course, I could have missed something, but I'm pretty sure of that. They've made some general development posts about the H550ST and a couple of vague, non-descriptive posts about the 75mm "M" motor but no official cert announcements, and they're usually really good at keeping the FB page current...

Instructions for the 75mm DMS

https://www.aerotech-rocketry.com/u...2637e_75mm DMS Instructions 5-20-14 Small.pdf

Tony

JohnCoker said:

now who will be the first to make a thrust curve for it?

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Done.

I spoke with Gary Rosenfield at Mudroc. He said that this was coming. Can't remember exactly, but there may be more 75's coming.

I have all of the data for it from Pail Holmes. I will make files for the new H and the M this weekend.


Mark Koelsch
Sent from my iPhone using Rocketry Forum

Machined aluminum tapped forward bulkhead. That's an interesting piece.

tfish said:

Instructions for the 75mm DMS

https://www.aerotech-rocketry.com/u...2637e_75mm DMS Instructions 5-20-14 Small.pdf

Tony

Click to expand...

Anyone hear about the price yet?


TA

I know it might be asking a bit much but if they could keep it at, or around $250 like the M-1297 under $300, it would be a game changer for the lvl 3 crowd. It would push me over the edge.


TA

no price set yet..

but here is some more info on the M

https://aerotech-rocketry.com/uploads/65f78a00-dd5e-4366-a872-95927bbedc31_AT M1350W SU jun 19.pdf

Tony

Some 75 mm full L's would be a nice addition.

4kids49 said:

Some 75 mm full L's would be a nice addition.

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Last I heard that was in the works. A Dark Matter version if I recall.

thobin said:

I know it might be asking a bit much but if they could keep it at, or around $250 like the M-1297 under $300, it would be a game changer for the lvl 3 crowd. It would push me over the edge.


TA

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There might be hope, seeing how the smaller motors compare surprisingly well on cost. The J270W DMS is only $2 more than the J350W reload for a small 38MM J motor. Who knows how much the aluminum bulkhead adds to the cost though.

Amazing idea for cost effectiveness.


Sent from my iPhone using Rocketry Forum

Hope AT will price the DMS close to the RMS 75/5120 list price , and not at the RMS 75/6400 pricing - although that would still be a deal considering the investment in AT or others 75mm hardware .

This and the new CTI M1101 White are both under 5200ns , brand new baby M motors .

Kenny

Biggest thing I see is AT supplying an igniter for an L3 motor :O

End users gluing in bulkheads?

tfish said:

no price set yet..

but here is some more info on the M

https://aerotech-rocketry.com/uploads/65f78a00-dd5e-4366-a872-95927bbedc31_AT M1350W SU jun 19.pdf

Tony

Click to expand...

Something doesn't seem quite right- I think there is an error in the propellant mass. For 1.97 kg of propellant to produce 5178 N-s would require an Isp of 268 s for that propellant. The (roughly) equivalent M1297W has 2.681 kg for 5417 N-s, an Isp of 206.

Additionally, for 4.808 kg loaded mass, that implies the casing/etc mass to be 2.83 kg. That just seems awfully heavy, even figuring in the aluminum bulkhead. For the M1297W, the case/etc mass is only 2.03 kg (4.708 loaded).

David

Wizard said:

Something doesn't seem quite right- I think there is an error in the propellant mass. For 1.97 kg of propellant to produce 5178 N-s would require an Isp of 268 s for that propellant. The (roughly) equivalent M1297W has 2.681 kg for 5417 N-s, an Isp of 206.

Additionally, for 4.808 kg loaded mass, that implies the casing/etc mass to be 2.83 kg. That just seems awfully heavy, even figuring in the aluminum bulkhead. For the M1297W, the case/etc mass is only 2.03 kg (4.708 loaded).

David

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You're right. That is very odd... I would expect the single use to have significantly less empty mass (and total mass, too).

It has to be a math error as there is no way the Isp = 266 s.

The 75 mm AT RMS M1297W appears to be the same motor as the 75 mm AT DMS 1350W with an Isp = 199 s. If I had to guess, the propellant weight in the M1350W should be 2670 grams not 1970 grams (flip the 9 into a 6) and with the propellant bore and the nozzle throat several thousands larger than the M1287W

https://www.thrustcurve.org/simfilesearch.jsp?id=982

https://aerotech-rocketry.com/uploads/65f78a00-dd5e-4366-a872-95927bbedc31_AT M1350W SU jun 19.pdf

Bob

Anyone hear anything on the grapevine recently about price or availability of the M1350 DMS?

I had asked one of the Vendors if he knew the price..he said yes, but couldn't share because it had not been announced yet .

Kenny

If I were a betting man, I would say $339 and 6 weeks out...........

Is there any way to do; head end ignition on these motors?


JD

JDcluster said:

Is there any way to do; head end ignition on these motors?




JD

Click to expand...

Why?

JDcluster said:

Is there any way to do; head end ignition on these motors?


JD

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Based on the way they are made, no. Forward closure's already installed with delay grain and all I'm quite sure.