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Now that I am Level 1 Cert should I switch to reloadable motors instead of DMS?

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ridnharley

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Could I save money going with reloadable motors or are their disadvantages?
Stick with DMS or not?
Going for Level 2 Cert soon.
 

o1d_dude

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I am L2 and prefer DMS whenever possible so there’s that.

If you launch regularly, have short lines at the pad, and easy retrievals, go for the RMS reloads.

I have none of those so the DMS allows me to get two, sometimes three flights at a launch.
 

heada

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Branch out. Look at RMS, CTI, Loki... Lots of options and lots of reasons to try different things.
 

OverTheTop

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Choose whatever makes sense for you :). Personally I only fly reloadables in HPR due to the fuels available.
 

Dudeman247.

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I fly both but more reloadable. There is more cost up front with buying motor casings as you probably know.
 

Chad

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one thing about having hardware, if you ever want to get into making your own research motors at least you'll have motor hardware and assembly experience.
 

AeroTech

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It’s nice having options. There are applications for both.
 

BABAR

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I’m L-0, but I am surprised no one has pointed out that it certainly must hurt more in the wallet if you lose a rocket with a reloadable motor case, or if a flight ends reaaaaalllly badly......... I guess with high power rockets and all their telemetry you don’t lose them as often?
 

tsmith1315

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I can confirm that ballistic return from 8k' will not damage 54mm AT hardware. Even when nothing else survives but the fins.
 

Mike Haberer

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In my analysis there are enough AT DMS engines in the 29 (10), 38mm (12) and 54mm (8) sizes that reloads aren't a terribly good value, especially if you are flying the larger engines in those classes on smaller airframes - if you lose a rocket you lose the hardware and there go your meager savings. The best reason to fly reloads in motors smaller than 75mm is if you want to fly propellants that aren't available in DMS load (but you still have choices with DMS - White Lightning, Blue Thunder, Redline and Dark Matter, so pretty good). If I go 38mm reloads, I'll do Cesaroni - brain dead simple. Any other form factor and reload assembly is pretty similar - go with whatever your club uses the most (more helpful hints) or your on-site vendor (if you have one) carries in inventory (most options available). Once you get to 75mm and above, your DMS options get a lot smaller (there are only 2 DMS motors at 75mm and 2 at 98mm) so reloads are almost a given, plus you're spending a lot of bucks and probably have trackers in your birds so losing the hardware is far less likely.
 
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afadeev

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Could I save money going with reloadable motors or are their disadvantages?
Stick with DMS or not?
Going for Level 2 Cert soon.
Nothing wrong with flying either RMS or DMS motors, and your decision should NOT be based on the L2 flight timing.

As you start planning ahead, you will figure out what are the most likely motors sizes and diameters that you will be building and flying (e.g.: 29mm G's & H's, or 38mm H's & I's, or 54mm J's & K's). Then collect the reload prices for both, and you will figure out that you will be financially better off buying a RMS case to go for the types of motors you will be flying more than 2-3 times.
Even then, you may prefer the simplicity, and lower risk of financial hit when flying out-of-sight-high with DMS motors, and there is nothing wrong with that.

A fellow forum member JLebow worked out this graph.
There is something very wrong with these graphs - RMS vs. DMS cost break-even is usually around 2-3 flights, not 10-25 !
 

Flyfalcons

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I like to fly both, depending on selection and cost difference. One huge benefit to DMS over reloads is prep time on the DMS is minimal, and clean up time is zero.

And yes @afadeev, depending on the motor used, the the DMS version may be only minimally more expensive than the reload, resulting in a considerable number of flights to tip the economic argument towards reloads. On Wildman, the J350W is 73.99 vs the J270W and J435WS at 79.99. If you can find a 38/720 full motor hardware for twelve dollars then let us know.
 

Theory

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IMHO reloads add an additional dimension to the hobby, one that I very much enjoy.

Also, reloads give the end user ultimate control over the assembly of the motor.

the only motor related failure that I’ve experienced in the last few years was a SU motor
 

Buckeye

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There is something wrong with the graphs, but the answer is not 2 or 3 as the crossover point!

From Wildman: the J350W is 73.99 vs the J270W and J435WS at 79.99. 38/720 full motor hardware is $130 (or $104). By my math, the cross over is 22 (or 18) flights, a far cry from 35.

Still, 22 (or 18) flights is a sobering high number to justify hardware purchases. The hardware ROI was much better years ago, I think. More DMS options are becoming available these days. If I was just starting out, I would focus on DMS for a while.
 

John Kemker

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In my analysis there are enough AT DMS engines in the 29 (10), 38mm (12) and 54mm (8) sizes that reloads aren't a terribly good value, especially if you are flying the larger engines in those classes on smaller airframes - if you lose a rocket you lose the hardware and there go your meager savings. The best reason to fly reloads in motors smaller than 75mm is if you want to fly propellants that aren't available in DMS load (but you still have choices with DMS - White Lightning, Blue Thunder, Redline and Dark Matter, so pretty good). If I go 38mm reloads, I'll do Cesaroni - brain dead simple. Any other form factor and reload assembly is pretty similar - go with whatever your club uses the most (more helpful hints) or your on-site vendor (if you have one) carries in inventory (most options available). Once you get to 75mm and above, your DMS options get a lot smaller (there are only 2 DMS motors at 75mm and 2 at 98mm) so reloads are almost a given, plus you're spending a lot of bucks and probably have trackers in your birds so losing the hardware is far less likely.
So, not disagreeing with you, but let me give an alternate perspective:

Since the casings are not cheap, I tend to take more care to ensure that I get the rocket back, at least the casing portion of it. Therefore, the concern about "there go your meager savings" becomes a moot point.

I will disagree with the Cesaroni decision: Higher costs due to HazMat fees for the 38mm reloads, as opposed to the non-HazMat fees of Loki or even AT reloads in that size. Cesaroni just doesn't make economic sense unless you're always buying on the field. Even then, you're paying for *someone's* HazMat shipping, even if it's the dealer's. Cesaroni costs become comparable once you get past 38mm, as everything above 38mm requires HazMat, no matter who manufactured it.

Some of us flew back when reloads were the main game for the average flyer. Sure, we'd fly the occasional H125, I65 or K250, but the costs compared to buying reloads for your hardware were prohibitive. Evidently, those costs have dropped to meet the market demands. (Or, reload costs have risen, take you pick.) The main reason you flew single-use was because the particular thrust profile you were looking for didn't exist in a reload. (Had a K125 98mm SU that I was going to fly in a minimum diameter rocket with a Nike-style fiberglass fin can and about the size of an EZI-65. Project was on the back burner, then lost it in the divorce. /sigh Ain't nobody to blame buy myself.)

Getting back into the hobby, I chose Loki because I prefer the snap-ring style hardware and the 38mm reloads are mostly non-HazMat shippable.
 

Ez2cDave

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Could I save money going with reloadable motors or are their disadvantages?
Stick with DMS or not?
Going for Level 2 Cert soon.
A couple of quick questions :

(1) What is your monthly budget for Rocketry ?

(2) How often do you plan on flying HPR rockets ?

(3) For you , personally, are there any advantages to DMS over Reloads, considering there are a larger number of re-loadable motors to choose from ?

Dave F.
 

OverTheTop

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I’m L-0, but I am surprised no one has pointed out that it certainly must hurt more in the wallet if you lose a rocket with a reloadable motor case, or if a flight ends reaaaaalllly badly......... I guess with high power rockets and all their telemetry you don’t lose them as often?
Yes, that happens occasionally. I have lost two significant rockets over the years. About $2k in hardware total. Running DMS would not have saved me the majority of the cost.
 

voltzwgn

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Another factor no one has mentioned is the waste factor.......... I'm becoming more and more aware of the amount of plastic and trash that I generate. Just got my L1 last weekend and used DMS motors more for the ease (isn't this part of the reason for we generate so much trash?) than anything else. But certainly looking at RMS in the future, I may be mistaken but it seems there is less trash generated by the RMS motor? Hopefully someone will correct me if this is a mistaken assumption.
 

Dustin Lobner

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I did L1 and L2 on DMS and will be doing L3 on a DMS as well. When I look at the cost delta of DMS vrs. hardware + reload, it's hard for me to justify the hardware for how little flying I'm realistically able to do. If I end up buying hardware sometime, it'll likely be for experimental things.

Great thing is that we have choices!
 

Eljay

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There's nothing wrong with using both. I show up at a launch with pre-loaded RMS cases and usually a few DMS motors as well for my "stretch goals" that I'll only do if the weather is good, lines are short etc.
 
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