DMS or RMS?

[secretagent]

Mostly fly CTIs here and haven’t had issues, but I often get DMS motors when they are on sale, and even used an M1350DMS for my L3 certification. There are some case-compatible loads (I currently have an AT M1297 loaded into a CTI 75mm case that I’ll fly in 2 weeks) so that you can play with both.

The DMS motors cost a little extra but at the 38mm size it’s fairly negligible; you may want to start with those.

 

[WizardOfBoz]

@Andrew Brown I really like the graph. But I suspect that two years has made a signficant difference.

My problem is that I'm trying to figure out a cheap (or at least the cheapest) way to get a J into my Super DX3's 38mm mount for an L2 cert attempt. Also, I want to fly a couple of H flights to 1) ensure that my electronics work, and 2) satisfy the guy who will approve my L2 flight if successful (he was wearing a "My spirit animal is a Cranky Turtle who Slaps People" tee shirt at the launch last weekend). I have an Aerotech RMS-29/360 case and the reload adapter kit, so I could use AT 240 or 360 motors for the "H" flights. I think that I'll go with an H180 in the RMS tube, and a slightly larger single use as well for the two "pre L2" flights.
For the "J" I think I need to use a 38mm, right? Saturday Ken (Performance Hobbies - thanks Ken!) sold me an I565 Vmax (video to follow - the rocket is on the pad one second and then just dissappears!) which was fun (video to follow). I borrowed a CTI motor case for that. Much easier to use than the AT RMS stuff, but both are manageable.
Anyway, I want to keep my 4.5lb, 4" rocket as low as possible while using the J motors. OR predicts about 4000' for most of the J motors. Any specific J recommendations?

 

[Rschub]

The Aerotech J270 is a DMS motor, it needs a delay tool, but otherwise very simple to use. Bonus, you can hang the casing on your wall with LEVEL 2 CERT written on it after the flight.
I have a thread elsewhere where I added drag plates to keep my rocket low. Weight and drag are really the only 2 variables you can change to affect altitude. All "J" motors are in a similar total power range, the different "flavors" just change how quickly or slowly that power is delivered.

 

[boatgeek]

@Andrew Brown I really like the graph. But I suspect that two years has made a signficant difference.

My problem is that I'm trying to figure out a cheap (or at least the cheapest) way to get a J into my Super DX3's 38mm mount for an L2 cert attempt. Also, I want to fly a couple of H flights to 1) ensure that my electronics work, and 2) satisfy the guy who will approve my L2 flight if successful (he was wearing a "My spirit animal is a Cranky Turtle who Slaps People" tee shirt at the launch last weekend). I have an Aerotech RMS-29/360 case and the reload adapter kit, so I could use AT 240 or 360 motors for the "H" flights. I think that I'll go with an H180 in the RMS tube, and a slightly larger single use as well for the two "pre L2" flights.
For the "J" I think I need to use a 38mm, right? Saturday Ken (Performance Hobbies - thanks Ken!) sold me an I565 Vmax (video to follow - the rocket is on the pad one second and then just dissappears!) which was fun (video to follow). I borrowed a CTI motor case for that. Much easier to use than the AT RMS stuff, but both are manageable.
Anyway, I want to keep my 4.5lb, 4" rocket as low as possible while using the J motors. OR predicts about 4000' for most of the J motors. Any specific J recommendations?

If you don’t have a case for the J in hand or available to be borrowed, then DMS is almost certainly the cheapest route to L2. When I checked, the J motors were all the same price, so pick what speaks to you. Of course, if you’re planning on flying J’s later, a case may be worth it.

 

[WizardOfBoz]

Thanks, guys. I'm trying to navigate the cost (for which one might have to be flexible) and availability (which, if the motor isn't avialable, I have to choose an alternate). The other thing is that I could buy a CTI case, but when are they restarting production for hobby motors? But frankly, although I enjoy big powerful J motors, I've really enjoyed the smaller HPR (e.g. H180 for the DX3) and larger MPR (e.g. a G80 for my Estes Argent). So buying a full set of AT or CTI 38mm mounts is not going be a good investment.

I've got to figure out kdenlive software so that I can edit my I566 launch video down to a manageable few seconds. Seriously, it seems like the rocket is there one second and it just disappears....

 

[Ronz Rocketz]

I've heard that CTI have had reliability issues. Could this be why they're limited availability now? (Just asking questions...)

I had the 38mm H130W and 29mm I200W shipped to Hawaii with no hazmat. Some vendors will ship a G80T DMS with no hazmat but most only allow the LMS motors to be shipped without hazmat.

Last week, we reloaded a H170M successfully in the dark with a flashlight. I'm very proud of that.

The Aerotech J270 is a DMS motor, it needs a delay tool, but otherwise very simple to use. Bonus, you can hang the casing on your wall with LEVEL 2 CERT written on it after the flight.
I have a thread elsewhere where I added drag plates to keep my rocket low. Weight and drag are really the only 2 variables you can change to affect altitude. All "J" motors are in a similar total power range, the different "flavors" just change how quickly or slowly that power is delivered.

Damn straight. I only had one 38/720 case so my son used the DMS in our drag race. It's kinda hard to mount a used J340M to the wall.

 

[cbrarick]

WizardofBoz: If the J is a bank-buster, then just stay L1. You can have plenty of fun in the H and I motor category.
Getting a merit badge (a L2 you will never fly again) seems to me to be the wrong way to do things. This is clearly stressing you out, and the hobby should never be stressful.

No shame in being "Just L1"

I have lots of friends who are L0 and have a great time with A-C motors, even at large regional launches.

 

[kjhambrick]

My problem is that I'm trying to figure out a cheap (or at least the cheapest) way to get a J into my Super DX3's 38mm mount for an L2 cert attempt. Also, I want to fly a couple of H flights to 1) ensure that my electronics work, and 2) satisfy the guy who will approve my L2 flight if successful (he was wearing a "My spirit animal is a Cranky Turtle who Slaps People" tee shirt at the launch last weekend). I have an Aerotech RMS-29/360 case and the reload adapter kit, so I could use AT 240 or 360 motors for the "H" flights. I think that I'll go with an H180 in the RMS tube, and a slightly larger single use as well for the two "pre L2" flights.

What kind of electronics are you flying ?

GREAT idea to fly a few H-motors before your L2 money shot -- especially if you are flying electronics for deployment.

Not that it matters for your personal journey to L2 but, I really LOVE the AT RMS 29/240 H180W motor and I just bought my first RMS 29/360 H268R last weekend that I am REALLY anxious to try ( I don't remember Redline propellants back when I un-BAR'd in March, 2000 )

For the "J" I think I need to use a 38mm, right? Saturday Ken (Performance Hobbies - thanks Ken!) sold me an I565 Vmax (video to follow - the rocket is on the pad one second and then just dissappears!) which was fun (video to follow). I borrowed a CTI motor case for that. Much easier to use than the AT RMS stuff, but both are manageable.
Anyway, I want to keep my 4.5lb, 4" rocket as low as possible while using the J motors. OR predicts about 4000' for most of the J motors. Any specific J recommendations?

Yes, since your Super DX3 has a 38mm motor mount, 38mm motors are your only option for a J-motor.

If you're flying electronics for deployment then no worries about motor ejection -- just leave out the BP and fill up the forward motor orifice with dog barf and tape it up nice and tight and fly it !

If you can borrow or buy an RMS 38/720 motor then the AT J350W is what I would in my rocket ( and that's what I did fly for my L2 re-cert last fall )

Otherwise, a DMS J270W, a DMS J425R or a DMS J435WS would be good options too.

OTOH, if Loki is available there are some AMAZING 38mm Loki Motors

HTH and good luck !

-- kjh

 

[boatgeek]

I've heard that CTI have had reliability issues. Could this be why they're limited availability now? (Just asking questions...)

This is an absolutely and completely uninformed answer, other than what's on the internet.

With that out of the way... It appears that the hobby business is a very small part of CTI's business, and is likely a hassle. The military industrial complex doesn't want green or red or smokey motors, they just want the same formula the same way and a thousand of them as soon as you can thankyouverymuch. And here's several wheelbarrows of cash. With the conflict ongoing in Ukraine, there's a lot of demand on their defense side. I think that's the most likely explanation for the availability issues. Any business interested in the bottom line would rather sell in large lots of identical items to the government than small lots of many different items to individuals.

I'm guessing that the reliability issues are mainly because the hobby side lost its biggest champion when Jeroen was sidelined by the fire years back. If there's no champion for a small side business then it gets neglected and things like this happen over time.

 

[WizardOfBoz]

@kjhambrick I'm only using the Eggtimer altimeter right now. I built it. It works, apparently. At least I can link to it at home. But at the site, I wasn't able to get it armed. Last weekend I didn't even try. I'll get it working using a G motor

I enjoy building the electronics and I'm currently building the EZ-DD from Eggtimer. Assuming I can get it working using an F40 or G74 or something about that size. If success then I'll get and build the Quantum or Proton flight computer for the DX3 and test it with an H180. If I have two dual deploy flights, and both are successful, I'll be reasonably confident that I can send the DX3 with a J.

I'd like to to the dual deploy, as it's interesting and it allows the use of a bigger motor.

Uhh uhh....

 

[4regt4]

Not that it matters for your personal journey to L2 but, I really LOVE the AT RMS 29/240 H180W motor and I just bought my first RMS 29/360 H268R last weekend that I am REALLY anxious to try ( I don't remember Redline propellants back when I un-BAR'd in March, 2000 )

Re: H268R. I've flown several of each H268R and I200W in the same rocket. 2.2" LOC BB X. For some reason, the H268R goes 5-10% higher, even though OR doesn't sim that way. Plus you get a nice red flame!

Hans.

 

[kjhambrick]

Re: H268R. I've flown several of each H268R and I200W in the same rocket. 2.2" LOC BB X. For some reason, the H268R goes 5-10% higher, even though OR doesn't sim that way. Plus you get a nice red flame!

Hans.

I love hearing that since I just bought my first H268R !

 

[Raythain]

WizardofBoz: If the J is a bank-buster, then just stay L1. You can have plenty of fun in the H and I motor category.
Getting a merit badge (a L2 you will never fly again) seems to me to be the wrong way to do things. This is clearly stressing you out, and the hobby should never be stressful.

No shame in being "Just L1"

I have lots of friends who are L0 and have a great time with A-C motors, even at large regional launches.

As a current L0 with aspirations, there are a couple of reasons I can think of to get a L2 merit badge.

1) TRA L2 would cover me if I want to do small research motors. Don’t need to break the bank on custom mixed L3 stuff. As far as I can tell the cost of entry for something like R-candy isn’t going to be cost prohibitive to someone who feels a couple of J motors a month might be too spendy.
2) I’ve heard (and this could be wrong) that you need to be L2 to serve as RSO. If that’s a role someone wants to volunteer in, merit badging for the cert to help the club is something I’d support any day.

Not saying that there isn’t a ton of fun to be had flying the small stuff (I’m loving where I’m at), but there are a couple of perks that an L2 affords that might be valuable if those are your interests. Just my 2 cents as someone looking “up” from the MPR world.

 

[4regt4]

I love hearing that since I just bought my first H268R !

Had to look at my spreadsheets...

The BB X hit 850fps on the I200, and 1020fps on the H268R. Same location, roughly similar temps. Being long, skinny, and not real big fins, that extra speed must have carried it to the higher altitude. Looking closer, the altitude difference was 4%. Just guessing, but a fatter rocket may produce the opposite results.

Hans.

 

[Art Upton]

I'm guessing that the reliability issues are mainly because the hobby side lost its biggest champion when Jeroen was sidelined by the fire years back. If there's no champion for a small side business then it gets neglected and things like this happen over time.

Yes, that ^

Since the fire weird problems have developed with lots of users.

Just with me , I have a H152 2 grain blue motor that the core is not fully cored all the way. If I had not noticed that 'An Earth Shattering Kaboom' would have occurred. I still have that motor.

I have had the other issue where the 38mm motor's nozzle that you screw in blows out and KATOs. I got a warrantee motor on one of those, ASAP on the field from Chris. Thank you Chris.

54mm CTI motors have different issues happening you can search here for. All mine were and the one I have left made some years before the fire.

 

[Art Upton]

Re: H268R. I've flown several of each H268R and I200W in the same rocket. 2.2" LOC BB X. For some reason, the H268R goes 5-10% higher, even though OR doesn't sim that way. Plus you get a nice red flame!

Hans.

I still have two of those H268Rs still in my Stash. But no 29/360 case. Must have lost it in a rocket, thinking the I motor.

I'll wait for a used 29/360 to turn up for sale

 

[kjhambrick]

As a current L0 with aspirations, there are a couple of reasons I can think of to get a L2 merit badge.

1) TRA L2 would cover me if I want to do small research motors. Don’t need to break the bank on custom mixed L3 stuff. As far as I can tell the cost of entry for something like R-candy isn’t going to be cost prohibitive to someone who feels a couple of J motors a month might be too spendy.
2) I’ve heard (and this could be wrong) that you need to be L2 to serve as RSO. If that’s a role someone wants to volunteer in, merit badging for the cert to help the club is something I’d support any day.

Not saying that there isn’t a ton of fun to be had flying the small stuff (I’m loving where I’m at), but there are a couple of perks that an L2 affords that might be valuable if those are your interests. Just my 2 cents as someone looking “up” from the MPR world.

And ...

With your Level 2 ...

3) You can apply for access to the TRF > Advanced Rocketry Topics > [Restricted] Research sub-forum.

4) You can purchase Propellant Grains and EMK's from The RCS Store

NOTE: A Mentor who knows what they're doing and Number 3 are is important before you 'fly off' and explore #4

-- kjh

 

[boatgeek]

4) You can purchase Propellant Grains and EMK's from The RCS Store

NOTE: A Mentor who knows what they're doing and Number 3 is important before you 'fly off' and explore #4

-- kjh

I admit that ever since learning that CTI Pink loads were just a red grain with some blue grains, I've wondered how many other colors one could brew up. That's probably the only way I'd do EX, and I'm not entirely sure I really want to do it.

 

[kjhambrick]

I still have two of those still in my Stash. But no 29/360 case. Must have lost it in a rocket, thinking the I motor.

I'll wait for a used 29/360 to turn up for sale

Same thing happened to my old well-used Dr Rocket 38/1080 ...

But I lost my patience and I am too slow for 'the good stuff' on the TRF > Forums > Manufacturers, Vendors, Sales & Deals > Yard Sale / Wanted sub-forum so I bought a new case from the Sirius Rocketry Online Store ... now I just need a forecast and a site that matches the 11.5k ft altitude TP will reach on an old J570W !

-- kjh

 

[bad_idea]

2) I’ve heard (and this could be wrong) that you need to be L2 to serve as RSO.

Yes, Tripoli requires L2 for RSO and L1 for LCO (see definitions section of the Unified Safety Code). I'm not sure about NAR.

Same thing happened to my old well-used Dr Rocket 38/1080 ...

But I lost my patience and I am too slow for 'the good stuff' on the TRF > Forums > Manufacturers, Vendors, Sales & Deals > Yard Sale / Wanted sub-forum so I bought a new case from the Sirius Rocketry Online Store

Dang it, I forgot you were looking for one, or I would have given you the heads-up on the 38/1080 I just bought from ndrocket. Hope I didn't snipe that one from you.

 

[kjhambrick]

Yes, Tripoli requires L2 for RSO and L1 for LCO (see definitions section of the Unified Safety Code). I'm not sure about NAR.

Dang it, I forgot you were looking for one, or I would have given you the heads-up on the 38/1080 I just bought from ndrocket. Hope I didn't snipe that one from you.

Nope, no worries !

You had already offered to loan me a case when I posted a TRF > [Wanted] - RMS 38/1080 Case thread ( THANKS for the offer, Stephen ) !

But it makes me nervous to fly equipment that belongs to other people -- even more nervious than I already am flying my OWN stuff high and fast

I watched TRF for a while and googled 'used aerotech RMS 38/1080 case' and didn't find a used one but the Price at Serius was pretty good so I bought one back in March ( along with a 38mm Plugged Threaded Fwd Closure that also went missing sometime over the past 20-some years ).

I kinda figured the case and the closure would turn up as soon as I bought new ones

But not yet

-- kjh

EDIT: p.s. You made me look ... I just now saw that you scored the 38/1080 case yesterday ! Congrats !!

 

[SolarYellow]

And ...

With your Level 2 ...

3) You can apply for access to the TRF > Advanced Rocketry Topics > [Restricted] Research sub-forum.

4) You can purchase Propellant Grains and EMK's from The RCS Store

NOTE: A Mentor who knows what they're doing and Number 3 are is important before you 'fly off' and explore #4

-- kjh

L2 also allows you to get creative with tweaking the hardware in mechanically useful and interesting ways.

People who do it talk about cutting and drilling grains as no problem and not a big deal. If true, that suggests that "cloning" some certified loads with components sourced from the RCS store could be a very cost-effective means of flying in the MPR and L1 realms.

 

[Ronz Rocketz]

I took the NAR L2 exam last week. The question came up, when am I allowed to modify a motor, and the answer is when the manufacturer approves. I had to laugh because Karl Baughman from Aerotech was sitting four feet away from me at the time.

 

[bad_idea]

Nope, no worries !

You had already offered to loan me a case when I posted a TRF > [Wanted] - RMS 38/1080 Case thread ( THANKS for the offer, Stephen ) !

Anytime. Any of my hardware I have at a launch that I'm not either using or have loaded to use or have already lent to somebody is available to borrow.

But it makes me nervous to fly equipment that belongs to other people -- even more nervious than I already am flying my OWN stuff high and fast

Worst case is the borrowed hardware becomes yours when it's lost or destroyed.

EDIT: p.s. You made me look ... I just now saw that you scored the 38/1080 case yesterday ! Congrats !!

Yes, I thought I'd get a spare. Losing cases sucks, but especially when you don't have a spare, plus I'm working on multiple rockets to take the 1080 case so may want to have multiple 1080s loaded at launches next season.

 

[cbrarick]

1) TRA L2 would cover me if I want to do small research motors. Don’t need to break the bank on custom mixed L3 stuff. As far as I can tell the cost of entry for something like R-candy isn’t going to be cost prohibitive to someone who feels a couple of J motors a month might be too spendy.
2) I’ve heard (and this could be wrong) that you need to be L2 to serve as RSO. If that’s a role someone wants to volunteer in, merit badging for the cert to help the club is something I’d support any day.

don't think you're going to save money making ex 38mm motors - you won't! In fact, you will probably spend more then a commercial load.
1. You need all the chems and they don't come in a one 38 mm motor's worth
2. You need processing equipment
3. You need liners and casting tubes, these can be difficult to source and costly, especially if you have them shipped.
4. You need O-rings and hardware, which most commercial flyers don't have (except you can use Loki)
5. You desperately need a motor - i don't care if it's rcandy or APCP, you can't learn safety off the internet.

EX is never a "Cost savings" but is something we do to have fun, learn, and make things that aren't commercially available. I personally make 3 and 4 inch motors and use my scrap for 54's I've completely gotten out of making 38's as they are a pain to pack.

 

[Art Upton]

54mm was my start in making a few motors. I joked that my first 54mm J motor cost $795 as that was the costs to get into it, casting kits with mandrels and stuff.

I did it for a little bit, but really working with chemicals was not for me. I sold the mixer and fixings.
It was fun for awhile.

Edit: things CATO from time to time also , and take out your MULE rockets.

 

[Raythain]

don't think you're going to save money making ex 38mm motors - you won't! In fact, you will probably spend more then a commercial load.
1. You need all the chems and they don't come in a one 38 mm motor's worth
2. You need processing equipment
3. You need liners and casting tubes, these can be difficult to source and costly, especially if you have them shipped.
4. You need O-rings and hardware, which most commercial flyers don't have (except you can use Loki)
5. You desperately need a motor - i don't care if it's rcandy or APCP, you can't learn safety off the internet.

EX is never a "Cost savings" but is something we do to have fun, learn, and make things that aren't commercially available. I personally make 3 and 4 inch motors and use my scrap for 54's I've completely gotten out of making 38's as they are a pain to pack.

I may not have been clear - not suggesting that it would be cheaper to make L1/L2 equivalent motors, that’s obviously a non-starter.

My point was more that if someone wanted to make their own little rcandy motors (like A, B, C impulse little) then a use case exists for the merit badge TRA L2. I shouldn’t have talked cost, that was tangential and distracting from the point. And maybe even at that small the required overhead would be costly enough that it wouldn’t be accessible for someone who doesn’t want to spend $150 a launch in motors.

And hard agree on point 5. Much better to learn from someone who’s done it before than to risk blowing something irreplaceable up. And a TRA L2 can open access to some places to make connections (like the TRF Research sub-forum).

Not trying to pick a fight, more thinking that each flier’s reason to cert a given level may be about something other than “I want to regularly fly these impulse motors.” And those two points (RSO and EX access) are specifically gated behind an L2 cert.

 

[AeroTech]

CTI no matter what is ALL Hazmat, none have been certed in the states for exemption.
There are many 29mm AT non-hazmat RMS reloads.

DMS is like CTI without the need to worry about loosing a case.
RMS provides non-hazmat in lots of the 29s and just a few 38s.

There was a time most everyone had at least a 29mm RMS 180 case

CTI started having problems after their fire with CATOs and now supply chain issues. [War related, but to more extent than ATs supply]

Currently I am flying from my "stash" I have had for some time on both brands of motors.

List of motors and reloads that qualify under limited quantity (LQ) hazmat-free shipping:

https://s3.eu-west-1.amazonaws.com/...h limited quantity 05-22-24_1716403043913.pdf

 

[Ronz Rocketz]

List of motors and reloads that qualify under limited quantity (LQ) hazmat-free shipping:

https://s3.eu-west-1.amazonaws.com/static.fw1.biz/Templates/170652/myimages/aerotech limited quantity 05-22-24_1716403043913.pdf

So the ones on green (including the G80T at 62.5g) has no hazmat but needs the LQ sticker on the package? Is there anything else the vendor needs to do when shipping?

Is this an ongoing updated list? Apogee mailed me the I200W reload to me the other month with no hazmat.

 

[bad_idea]

Is this an ongoing updated list? Apogee mailed me the I200W reload to me the other month with no hazmat.

I think this list gives the additions to the no-hazmat offerings that are due to the new way of packing and shipping. The I200 was already no-hazmat.