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3stoogesrocketry

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Probably no more than a couple hundred per year. I guess it is possible to sell two versions.

If you’re using this for an upper stage you are going to friction fit or use some other means, with no thrust ring at all so the aft end of the motor will fit into the booster tube, right?

Mine will
H13 thrust rings- My opinion: sell with the thrust rings. This will result in fewer issues, toasted rockets, and warrantee complaints from inexperienced users. Those who want to use the motor in a fashion that requires no thrust ring will know how to remove it.

The caveat, however, is whether selling with a thrust ring will delay the time to market... does a thrust ring mean that it would have to be re-certified? (yes, I'm salivating already).

Does cutting / grinding / sanding a integral thrust ring that is glued in with the nozzle turn said motor into a ex motor ?
 

Dugway

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I ran into an issue last weekend where I had to sand three SU Aerotech motors with integral thrust rings in order to fit them in a cluster mount. Reload casings work fine since the thrust rings have two gaps 180 degrees apart, I guess for using a wrench or something. I wish that all single use motors had the same thing, two "flat spots" in the thrust ring on opposite sides of the case.
 

emckee

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I ran into an issue last weekend where I had to sand three SU Aerotech motors with integral thrust rings in order to fit them in a cluster mount. Reload casings work fine since the thrust rings have two gaps 180 degrees apart, I guess for using a wrench or something. I wish that all single use motors had the same thing, two "flat spots" in the thrust ring on opposite sides of the case.
But then what do you do in the case of a 7-motor cluster like the Loc Ultimate? Should thrust rings have flat spots every 60 degrees (this would allow close positioning for side-by-side clusters as well as hexagonally-close-packed arrangements)?

My opinion: It's not reasonable to ask the supplier to develop a product that fits every possible application or use scenario for something that is mass marketed - there are just too many unforeseeable permutations. That said, if the manufacturer can offer tips/recommendations so that the end user can modify the motor without compromising the design parameters, that might be ideal.

And FWIW, I'm dealing with the clustering arrangement issue myself... putting 7 DMS or reload cases in close formation is a bugger.
 

boatgeek

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I would say no.
...That said, if the manufacturer can offer tips/recommendations so that the end user can modify the motor without compromising the design parameters, that might be ideal.
Hear hear! The best way to make a modification not be EX is for the manufacturer to tell you that it's OK to do it. A simple line in the instructions like below would make all of these mods fly under standard (vs. EX) rules.

"The glued on thrust ring may be completely or partially removed if required. The flier should take care to not damage the case tubing below the thrust ring. If more than [X%] of the thrust ring is removed, the motor will require other means of retention."

Obviously, Legal (and Engineering) will need to wordsmith this, but it would cover most of the situations discussed above.
 

emckee

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ok, now that I'm thinking more on the it, I like the idea of an aft closure that is essentially a hex shaped thrust ring rather than the current circular one. I'm not sure about the machining cost delta vs a round one, but it would eliminate the need for special "wrenches" for closure tightening - anyone could tighten a closure with a standard wrench or get a better grip by hand. No more stuck closures.

The caveats, however, bear consideration: (1) users could over-tighten the closures with wrenches and potentially strip threads. (2) the hex shape would concentrate the force of the motor more locally on the MMT. Cardboard tubes might not hold up (or would wear out earlier), though FG would probably be fine.

Aerotech - have you considered this?
 

kbRocket

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Please no thrust ring on the H13 unless removal is permitted (1) without making it a research motor, thus limited to Tripoli L2+, and (2) without being disqualified from Tripoli records. A long burn H would be an awesome high altitude minimum diameter candidate.
 

AeroTech

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I think the negatives outweigh the positives on this one.

ok, now that I'm thinking more on the it, I like the idea of an aft closure that is essentially a hex shaped thrust ring rather than the current circular one. I'm not sure about the machining cost delta vs a round one, but it would eliminate the need for special "wrenches" for closure tightening - anyone could tighten a closure with a standard wrench or get a better grip by hand. No more stuck closures.

The caveats, however, bear consideration: (1) users could over-tighten the closures with wrenches and potentially strip threads. (2) the hex shape would concentrate the force of the motor more locally on the MMT. Cardboard tubes might not hold up (or would wear out earlier), though FG would probably be fine.

Aerotech - have you considered this?
 

tollyman

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Hello, I have an Aerotech 54mm 2560 case and I just bought the RAS for it. The RAS comes with an ejection style floating forward closure the required spacers and a threaded ring to hold it all in place. If I needed to have a plugged/threaded forward closure, could I use my existing plugged/threaded closure in place of the threaded ring. I would not put any charge in the well for the floating forward closure. I know there is a plugged/threaded floating forward closure but I if I dont have to buy it id rather not. Thanks
 

mikec

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If I needed to have a plugged/threaded forward closure, could I use my existing plugged/threaded closure in place of the threaded ring.
That won't work. The closure sits below the spacers and the standard closure won't do so, hence the need for the floating one.

You can use the regular closures if you don't use the spacers, of course, but then you're not using any part of the RAS.

Instructions here: http://aerotech-rocketry.com/upload...54-2800 Reload Adapter Instructions v2019.pdf and http://aerotech-rocketry.com/upload...0_reload_adapter_instructions_rev_1-16-20.pdf
 

tollyman

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That won't work. The closure sits below the spacers and the standard closure won't do so, hence the need for the floating one.

You can use the regular closures if you don't use the spacers, of course, but then you're not using any part of the RAS.

Instructions here: http://aerotech-rocketry.com/uploads/1ec96b6c-f224-4be8-b024-9332a430af6c_ 54-2800 Reload Adapter Instructions v2019.pdf and http://aerotech-rocketry.com/uploads/68330901-7fba-4dbd-9bf5-3cdb7de473ba_ 54-2800_reload_adapter_instructions_rev_1-16-20.pdf
My idea was to use both the floating forward closure and the standard closure. The standard closure would simply replace the threaded ring that usually holds the spacers and floating closure in place. Using the standard closure and the floating closure is where my question rests.
 

Jmhepworth

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My idea was to use both the floating forward closure and the standard closure. The standard closure would simply replace the threaded ring that usually holds the spacers and floating closure in place. Using the standard closure and the floating closure is where my question rests.
That makes me curious. I doubt it’s been tested, but I can’t think of a reason why it wouldn’t work. Wondering what AT will say.
 

3stoogesrocketry

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My idea was to use both the floating forward closure and the standard closure. The standard closure would simply replace the threaded ring that usually holds the spacers and floating closure in place. Using the standard closure and the floating closure is where my question rests.


That will work . I did one 2 years ago exactly as you described.
 

rocketace

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I cannot speak for 54mm, but looking at my 38mm I would not recommend it. The standard closure does have a lip that stick out further than the threads on the RAS closure. You could get it on, but it won't fully thread. For the 38mm AT does make a threaded RAS closure, maybe they do for the 54mm as well.
IMG_6319.JPG
 

GalantVR41062

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I also have the 54 RAS and the thought crossed my mind with a MD bird to fly it this way also.

20200917_220241.jpg


I do not have any 54mm loads for this case but I have a G69n loaded in my 38/240 case and tried my threaded forward closure. The closure does not thread in all the way as Rocketace showed.

20200917_215749.jpg
 

AeroTech

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Correct, it won’t thread in completely because the portion of the closure below the threads is already a part of the floating closure. You are duplicating function when you use both closures. For the RAS concept, we split a standard closure into two pieces from a functional standpoint.

I also have the 54 RAS and the thought crossed my mind with a MD bird to fly it this way also.

View attachment 432098

I do not have any 54mm loads for this case but I have a G69n loaded in my 38/240 case and tried my threaded forward closure. The closure does not thread in all the way as Rocketace showed.

View attachment 432097
 

tollyman

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Correct, it won’t thread in completely because the portion of the closure below the threads is already a part of the floating closure. You are duplicating function when you use both closures. For the RAS concept, we split a standard closure into two pieces from a functional standpoint.
From what I can tell on the 38, there are more threads on the standard closure. So that begs the question, even with threads sticking out, would it be okay to fly in that configuration? The idea is that I don't want to buy another forward closure if I have, but it needs to be threaded
 

mikec

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even with threads sticking out, would it be okay to fly in that configuration?
Define "okay". Will it work? Probably. If there's an issue and the case is damaged, could you request warranty replacement? No. Is it certified for use at a non-research launch? Not really.
 

AeroTech

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I agree with this comment.

Define "okay". Will it work? Probably. If there's an issue and the case is damaged, could you request warranty replacement? No. Is it certified for use at a non-research launch? Not really.
 

DeeRoc29

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Balsa Machining lists an I75WS under Aerotech DMS on the HP motor page. I don't see a reference to this motor anywhere else. Is it a real motor and if so what are the specs,?
 

Maxwelljets

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Balsa Machining lists an I75WS under Aerotech DMS on the HP motor page. I don't see a reference to this motor anywhere else. Is it a real motor and if so what are the specs,?
I think that's just a typo. The motor is actually the I175WS.
 
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