Confused at RMS hardware

[prfesser]

There is a limit to how much propellant can be crammed in an 18x70mm casing, which is why the best you might get out of one is a baby E (full D is more do-able).

I wonder how the market would react to longer 18mm motors, and whether they'd be a viable product. AT used to make 18mm full-E and baby-F motors, many moons ago. Of course there's the problem of shoving them in a low-power kit, most of which are designed to NOT take longer motors.

A solution that might not be prohibitively expensive would be to offer new, longer casings to fit the 18/20 closures (likewise for the 24/40 or 24/60). It *might* be possible to use currently-produced grains, just add a grain or two. Lots of testing would be needed; longer skinny motors, especially in small diameters, are problematic.

 

[mh9162013]

There is a limit to how much propellant can be crammed in an 18x70mm casing, which is why the best you might get out of one is a baby E (full D is more do-able).

I wonder how the market would react to longer 18mm motors, and whether they'd be a viable product. AT used to make 18mm full-E and baby-F motors, many moons ago. Of course there's the problem of shoving them in a low-power kit, most of which are designed to NOT take longer motors.

A solution that might not be prohibitively expensive would be to offer new, longer casings to fit the 18/20 closures (likewise for the 24/40 or 24/60). It *might* be possible to use currently-produced grains, just add a grain or two. Lots of testing would be needed; longer skinny motors, especially in small diameters, are problematic.

I'd love to see more 18mm options, as that's my preferred engine size. All of what you said makes sense and if I can extrapolate and summarize: the return on the investment on a longer 18mm motor system doesn't justify the development.

 

[SolarYellow]

There's someone on this forum who does EX motors that are quite long in 18mm. Nothing commercial I know of.

 

[jmasterj]

I'd love to see more 18mm options, as that's my preferred engine size. All of what you said makes sense and if I can extrapolate and summarize: the return on the investment on a longer 18mm motor system doesn't justify the development.

That's a bingo.

There's someone on this forum who does EX motors that are quite long in 18mm. Nothing commercial I know of.

I think it's @Rocketjunkie.

 

[loopy]

I got a 29/40-120. Haven't used it yet but sold as able to handle from 40 to 120 and in between. Not so?

It can handle E-G loads as advertised. The other comments you're seeing are about the 24/40 and 24/60 cases. Entirely different beast.

 

[Rocketjunkie]

That's a bingo.


I think it's @Rocketjunkie.

Up to 12" long, full F23. 3.5 sec burn

 

[prfesser]

There's someone on this forum who does EX motors that are quite long in 18mm. Nothing commercial I know of.

Yes, RocketJunkie has been making motors for rather longer than I have. He knows what he's doing. The difficulty lies in making such motors commercially. Tom has had a few CATOs, not unexpected in Research motors. But a commercial product probably shouldn't have any CATOs at all in the final testing phase. A few will CATO in consumer hands, regardless...poor handling, starter placement, etc.

 

[n3tjm]

I would love to see a RMS version of the 18mm E45 and F55

 

[Velocity Aerospace]

So I'm wanting to get into reloads. The smaller ones I think are pretty straight forward, and I will probably start there. But in my ambition, I got a 38/600 casing. For my L.1, I changed to using a dms, but for reloads of that size, it comes with a forward seal disk, so how exactly does it work/how is it installed?

 

[tsmith1315]

It goes goes in the forward end of the liner, part #9 here:



From this drawing:
https://d11fdyfhxcs9cr.cloudfront.n...yimages/38-600_i435t-s_assy_1648672965435.pdf

I'd suggest getting familiar with the document linked on this page. There are drawings of most motors, cases, reload instructions, motor listings (matrix), etc

https://www.rocketmotorparts.com/page/aerotech-resources

 

[techrat]

I have the 24/40 and a 29/40-120, and they are both quite useful. For starters, in the 24/40 you can use lower thrust motors I've never heard of before, like a D9 or an F12, which provide interesting, long burn flights for rockets light enough to get off the pad with that lower thrust. I've run plenty of F motors in the 29/40-120, but just bought my first set of G motors for this case, so next month is going to be interesting. After building 5 or 6 motors, you find the process pretty straightforward, although the first few times it seems like a tough job. Eventually the process clicks into place.

 

[Velocity Aerospace]

It goes goes in the forward end of the liner, part #9 here:

View attachment 597885

From this drawing:
https://d11fdyfhxcs9cr.cloudfront.n...yimages/38-600_i435t-s_assy_1648672965435.pdf

I'd suggest getting familiar with the document linked on this page. There are drawings of most motors, cases, reload instructions, motor listings (matrix), etc

https://www.rocketmotorparts.com/page/aerotech-resources

This is immensely helpful. Thank you so much

 

[tsmith1315]

This is immensely helpful. Thank you so much

You're welcome!

The Master Motor Matrix shows you all Aerotech & Quest motors, the main numbers you need to know, the RMS case needed (if required), any special closure requirements (extended, plugged, small hole) for that reload, and whether is requires hazmat shipping. A lot of information in one place!

Your 38/600 is a great case. Aaaand, if you purchase a 38mm RAS, that will allow you to fly 38/480 and 38/360 loads in your 600 Ns case. That's like 18 more motor choices available beyond the 5 offered for the 38/600 alone! It simply replaces the single-piece forward closure with a two-piece closure/thread ring and some spacers to move the seal disk+closure down against the fuels grains.

 

[Kane]

This is immensely helpful. Thank you so much

+1 on getting the RAS. Once you start collecting more cases, you'll see it allows you to get away with only having every other or every third case size.
Also, regarding the forward seal disk that came with your 38/600, the seal disk is not used for every reload that goes in that case. Be sure to check the reload assembly instructions.

 

[kjhambrick]

The RAS is new since I left and then returned as a REBAR.

In the olden days, I had to have one of each of the RMS Motor Systems that I wanted to Fly.

I like the RAS but one thing I liked about having one of each casing was that I could prep the motors at home in my shop before leaving for a launch -- one less thing to do on the field to fly the rocket.

But I am still going to get a 38mm and 54mm RAS

-- kjh

 

[SolarYellow]

I like the RAS but one thing I liked about having one of each casing was that I could prep the motors at home in my shop before leaving for a launch -- one less thing to do on the field to fly the rocket.

You can still do that. It just lets you use one case for multiple different reloads.

 

[Antares JS]

This is immensely helpful. Thank you so much

Just be very careful to remember not to throw your seal discs away when cleaning out the case between flights.

 

[waltr]

Just be very careful to remember not to throw your seal discs away when cleaning out the case between flights.

I've almost done that and know a few people that did that.
I put a piece on masking tape on the case after loading with the re-load in it and "Disc Seal" to remind myself.

 

[kjhambrick]

I've almost done that and know a few people that did that.
I put a piece on masking tape on the case after loading with the re-load in it and "Disc Seal" to remind myself.

Good idea, @waltr, and BTDT ...

Fortunately I put my launch site trash in a bag and haul it home with me.

I figured out that 'something was missing' when cleaning cases the next eve at home.

Fortunately I found my seal disk in the ashes of a 38mm J-motor in the 'big' outside trash can.

What's REALLY killing me is I used to have a Dr Rocket RMS 38/1080 motor system, including a seal disk and I have not been able to find it in my old rocketry boxes.

I've not opened and inventoried all the boxes yet so there is hope.

But I've got an unopened J570-14W in my magazine and my 1.9 inch Vulcanette REALLY wants a hot ride to 12k ft

I REALLY need to find that 38/1080 motor !

-- kjh

EDIT: grammar

 

[waltr]

funny the Seal disc has come up. I know I ordered a 38mm seal disc with last reload order. Now I can't find it.......

To the OP:
Just follow the instructions that come with the reload. Most important is identify the O-rings and where they go.

 

[tsmith1315]

But I've got an unopened J570-14W in my magazine and my 1.9 inch Vulcanette REALLY wants a hot ride to 12k ft

Come on over and fly with us, you can use my case.

 

[kjhambrick]

Come on over and fly with us, you can use my case.

Now that is a GREAT idea Tim !

We've got VERY scary dry conditions in Central TX.

So dry that I've decided to not even fly Estes Motors at the elementary school with the girls.

Seven year old Ellie gets it but three year old Evie does not understand why she can't fly her rockets --- it's killin' me to tell her 'no'

I've already decided if I can't find my RMS 38/1080 I should replace it with an RMS 38/1320 Case and a 38mm RAS System ...

But then again, maybe it's about time for a long road trip to Central GA ...

-- kjh

 

[loopy]

Good idea, @waltr, and BTDT ...

Fortunately I put my launch site trash in a bag and haul it home with me.

I figured out that 'something was missing' when cleaning cases the next eve at home.

Fortunately I found my seal disk in the ashes of a 38mm J-motor in the 'big' outside trash can.

What's REALLY killing me is I used to have a Dr Rocket RMS 38/1080 motor system, including a seal disk and I have not been able to find it in my old rocketry boxes.

I've not opened and inventoried all the boxes yet so there is hope.

But I've got an unopened J570-14W in my magazine and my 1.9 inch Vulcanette REALLY wants a hot ride to 12k ft

I REALLY need to find that 38/1080 motor !

-- kjh

EDIT: grammar

When I moved in December, I lost my 38/360 case. Looked EVERYWHERE for it. Went to a HPR launch in the spring with my LOC Nuke Pro Maxx. went to load the motor into the rocket...and found my 38/360 case.