Purpose of LMS motors?

I don't really understand. Why do LMS (Aero-Tech) motors exist?
Like why would someone spend an extra 4 bucks just to assemble a SU motor?
https://www.buyrocketmotors.com/aerotech-g77-redline-29-mm-single-use-loadable-motor-system-lms/

Assembled, they’d likely require Hazmat shipping.

https://www.apogeerockets.com/Rocke...?cPath=7_265&zenid=dpmobh8e71icjunsm7b789nsp1

Chris



Sent from my iPhone using Rocketry Forum

The reloadable version of this requires hardware at a cost of ~$80 msrp (https://www.buyrocketmotors.com/aerotech-rms-29-120-motor/). The LMS has everything you need at about a fifth of that cost including the reload. It's single use of course so you discard it after launch but if you're looking to fly only a few times or risk losing the hardware on say MD flights then it's a good choice. These are also appealing if you're looking at clustering.

Also, an assembled ready to go version of a similar motor (say a G79W) requires HAZMAT shipping, which is $32 (FedEx) plus actual shipping. Call it $20 for shipping to wherever so $52 to ship a single use version versus a fifth of that for USPS Parcel Post.

I can't answer for LMS, but I have a new DMS H219T-14A to use on a L-1 certification flight attempt. I already had a 38-480 RMS casing, but this saves me from buying a 240 or 360 casing to fly one H for one cert. So for high power the single use makes sense by economics. Most people recommended cert with an H on here. I don't own any MPR motors or rockets yet.

The other nice thing about LMS is being able to adjust the delay before assembly. I like to fly the F27, but it's only available as -4 or -8, so when I can get them, I'll get the F27-8 LMS, which I can drill to anything less.

dpower said:

The other nice thing about LMS is being able to adjust the delay before assembly. I like to fly the F27, but it's only available as -4 or -8, so when I can get them, I'll get the F27-8 LMS, which I can drill to anything less.

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Great point!

Andrew_ASC said:

I can't answer for LMS, but I have a new DMS H219T-14A to use on a L-1 certification flight attempt. I already had a 38-480 RMS casing, but this saves me from buying a 240 or 360 casing to fly one H for one cert. So for high power the single use makes sense by economics. Most people recommended cert with an H on here. I don't own any MPR motors or rockets yet.

Click to expand...

The DMS H219T is a great motor. I flew it 2 times in a LOC Mini Magg.

Andrew_ASC said:

I can't answer for LMS, but I have a new DMS H219T-14A to use on a L-1 certification flight attempt. I already had a 38-480 RMS casing, but this saves me from buying a 240 or 360 casing to fly one H for one cert. So for high power the single use makes sense by economics. Most people recommended cert with an H on here. I don't own any MPR motors or rockets yet.

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So why don't you think you won't be buying a 38/240 or 38/360 case in the future? When you start flying L1, you will want to have some options so you can "fly the field" based on weather and wind conditions. Might as well open that wallet and get those now.... That will give you a good taste of HPR.

Or pick up the Reload Adapter System (RAS) for the RMS-38 cases, then the 38/480 case can also fly 38/360 and 38/240 loads, and you can pick up the 38/720 case to do those loads as well as 38/600. So it gives you the ability to fly more loads with fewer cases, at least until you wish you had more cases because you want to have more motors built before the launch.

dpower said:

The other nice thing about LMS is being able to adjust the delay before assembly. I like to fly the F27, but it's only available as -4 or -8, so when I can get them, I'll get the F27-8 LMS, which I can drill to anything less.

Click to expand...

You absolutely can adjust single use motors. You just have to temporarily remove the powder.

In my experience the LMS costs the same as single use. I think you're comparing it to a G77R reload for the 29/120 case ("High Power Style"). In this example LMS has the advantage over SU of being available. Might even come with a Copperhead.

The LMS have advantages and disadvantages similar to RMS except cost breakdown .. except LMS requires epoxy too plus mine called for CA on the thrust ring (just use tape, it's better than gluing yourself to the case). I did it once due to just having bought another case yadda yadda.

If you'd be interested in a CTI, see if your vendor has Certify with Us. Once you're certified you can't do it again at that level.

chrisudy said:

Assembled, they’d likely require Hazmat shipping.

https://www.apogeerockets.com/Rocke...?cPath=7_265&zenid=dpmobh8e71icjunsm7b789nsp1

Chris



Sent from my iPhone using Rocketry Forum

Click to expand...

THIS ^^^

AT does all kinds of little tricks to prevent their motors from requiring Hazmat shipping, LMS vs DMS is one of them. By making the grains smaller and packaging them separately they avoid Hazmat shipping, though you do have to put the one-time use motor together. It's silly really... if it caught on fire it wouldn't matter if you had one big grain or two smaller ones, but that's how the shipping regulations work. They've started doing this with some of the HPR RMS reloads, too... the non-Hazmat HPR reloads are extremely popular.

Off topic. Handeman you have a valid point especially to adapt a rocket to field conditions. I will look into Loki H class hardware in a 38-360 size and also a RAS for Aerotech casing. Planning on a 38/720 eventually. Loki ships pellets in 38mm sizes to certain I motors that avoids hazmat charges. I started HPR with the 38/480 AT setup I got used on a deal. Originally I bought that size as a spare for the student project out of pocket and to L-1 with. Just started another full semester of classes. If I could've got controls lecture this semester and thermal component design I could graduate by this summer but not enough profs teaching these classes. No one wanted to teach thermal component this spring. I'll either need a JLCR or a H class motor casing eventually. Already have a HAM license and a TeleGPS. Right now I think I am not flying enough yet to put a casing to good use and the DMS H is subbing that need temporary.

Loki doesn't have a 360 size case. USPS shippable motors are available in the 120, 240 and 480 cases, though.