Aerotech SU motors dimensions wanted

[Arfang]

Good day everyone,

I'm currently designing parts for two MPR/HPR projects and I'm wondering if anyone could provide me with dimensions for Aerotech SU motors. I understand that a 29x124 motor has a 29 mm casing diameter and a 124 mm overall length, but what about the nozzle diameter and length for instance?
I'm particularly interested in G,H and J class motors.

I've attached a drawing to give you an idea of what I'm looking for.

Any help is more than welcome!

 

[tim cubbedge]

AT only makes single use motors up to G impulse. Are you sure you are not referring to RMS or DMS motors?

 

[crossfire]

DMS is single use.

 

[Arfang]

AT only makes single use motors up to G impulse. Are you sure you are not referring to RMS or DMS motors?

You're right, I meant SU and DMS. I was only able to find RMS drawings unfortunately.

 

[Steve Shannon]

You're right, I meant SU and DMS. I was only able to find RMS drawings unfortunately.

The diameter and length of the thrust rings are pretty standardized between companies so they’ll fit in commercial motor retainers, such as Aeropack, Giant Leap, etc. make. So, the dimensions provided by the RMS drawings are enough.
Be sure your motor mount tube is open on the forward end so any length motor will fit.

 

[Arfang]

Thank you for your input. If I understand correctly, the SU and DMS forward closure has the same dimensions as on a RMS for a given motor diameter and the thrust ring is also the same size.

However, from what I can see, they don't have the same nozzle position in regards to the thrust ring. See my attachment below (not to scale).

In other words, what I need is to define an OML for the motor so I can design the remaining parts accordingly.

 

[mikec]

I've never found a source for the precise dimensions of DMS motors.

Many of the DMS motors don't have a protruding nozzle, the exit is basically flush with the bottom of the thrust ring. Others have some protrusion, and the L1000 has a fairly large RMS-like nozzle. There seems to be a lot of variability across the product line (based on a random collection of spent motors I have lying around.)

As Steve says, it's been possible for Aeropack to design something that retains all the motors on the market, and if you just leave the MMT open at the front then it doesn't much matter what that end looks like, grossly.

You'd have to have a good reason to try to spec things more tightly IMHO.

 

[Steve Shannon]

The forward closure is installed inside the case. The OD of the forward closure is no greater than the case.

 

[PBic]

Thrustcurve.org is a great resource for motor length data.

 

[mikec]

Thrustcurve.org is a great resource for motor length data.

Sure, if you don't mind that it may or may not include the length of the forward closure, and never does for the nozzle -- I don't think there's consistency about that. It's completely sufficient for most purposes.

 

[CoyoteNumber2]

AT only makes single use motors up to G impulse.

Are you sure?
https://www.thrustcurve.org/motorsearch.jsp?id=1132

 

[o1d_dude]

I use Single Use and DMS interchangeably.

Thrustcurve.org does, too, in a manner of speaking. See the Motor Guide.

 

[tim cubbedge]

Are you sure?
https://www.thrustcurve.org/motorsearch.jsp?id=1132

A little bigger than what the OP was asking, no?

 

[CoyoteNumber2]

A little bigger than what the OP was asking, no?

My reply was to you.

 

[tim cubbedge]

My reply was to you.

ok. my bad.

 

[Arfang]

Thank you all for your replies. I will take into account that only the casing diameter and overall motor length are fixed values and design accordingly.

 

[cwbullet]

Does anyone have the dimensions of the hex at the forward end?

 

[tfish]

Does anyone have the dimensions of the hex at the forward end?

An 11/16ths socket fits nicely on them..

Tony

 

[tfish]

attached is a pdf of Aerotech 2020 DMS brochure..



Tony