Ye Olde Rocket Forum

Ye Olde Rocket Forum (
-   Projects (
-   -   Semroc SLS Laser-X semi-clone (

5x7 11-12-2019 04:40 PM

Semroc SLS Laser-X semi-clone
1 Attachment(s)
I built a Laser-X in the 70’s and it’s a favorite rocket. The SLS Laser-X was always a kit I was interested in but I waited too long. Recently Erockets started to clearance most SLS parts and I was browsing through and the SLS Laser-X motor mount in all its laser cut glory was there, for a song. The motor mount includes 12 display coolant vanes, four centering ring spacers and two centering rings, one with eight notches to interface with the spacers and motor mount locking tabs, the other with 12 slots for the ‘coolant vanes’ and four notches for the spacers. The tremendous intricacy of these laser cut parts around a 29 mm tube and the low price kept me coming back and to look at the picture.

5x7 11-12-2019 04:58 PM

1 Attachment(s)
I downloaded the SLS Laser-X instructions from the old Semroc site and looked at what parts were available at e-rockets. All the parts were available except the baffle disc and the full length main tube. The baffle could be omitted from the build, since shorter tubes were available I felt I could piece it together but that would require some modification of the interlocking fin tabs. I ordered the parts, most critical were the Large tubes in unusual diameters, the nosecone, transition, Laser cut fin set, the interchangeable motor mount, and the instructions. I got the parts and realized how neat it would be to be able to use interchangeable mounts which Semroc designed specifically for this rocket. I posted here to see if anyone had an LT-225 14” or longer and Chas came through and I bought it from him. In addition, he had a 225 bulkhead I could drill to make the baffle and included that also. I got vinyl decals from Stickershock since erockets no longer had them. The only minor issue with the decals is there is a white border around each decal, so I’m going to try to find a white that matches.

I decided to make up a complete kit before starting so I cut the tubes and slotted the main tube. Here are the main kit parts without recovery system.

5x7 11-12-2019 05:02 PM

2 Attachment(s)
As I mentioned the SLS Laser-X had two other interchangeable motor mount kits available, one a quad 18 complete with decorative cooling vanes, and a plain Jane dual 24 mm mount. Looking at reviews, folks have had a lot of fun with the cluster mounts. Erockets had some of the specific parts for each of the cluster mounts, the spacers for the 24mm dual mount and the cooling vanes and spacers for the quad 18mm mount. Erockets also had plain interchangeable mounts and rings for the 225 tube for both 29 and 24 mm mounts and other various parts to make the specialized interchangeable mounts. The key to making these are the centering rings from the 29mm mount to use as a pattern for the notches in the other parts and then Chas sent me copies of the instructions for these which was critical because the quad 18 is complex and the dual 24 has an unexpected placement of the spacing ribs revealed in the instructions.

5x7 11-12-2019 06:25 PM

3 Attachment(s)
The twin 24 mm mount is simple, but the fin set came with 12 additional cooling vanes that were also included with the main motor mount so I decided to extend the mount tubes to allow at least four decorative cooling vanes to be added. The pics are the mount spacers from Erockets with dual 9-225 rings from Erockets, marked (incorrectly) for notching, after (correctly) notching, and and a dry fit after notching. This mount will use long engine hooks that accomdate 95mm motors.

5x7 11-12-2019 06:51 PM

3 Attachment(s)
The other interchangeable mount is quad 18mm. Although the spacers and vanes were available, the specialized rings were not. The fwd ring is just a 115-225 interchangeable. So I picked up a set of those, and a 115-175 for the mid ring to attempt to cover the tubes and provide the notches needed by the other spacers. The aft ring that centers the four 18mm tubes still needs to be completed. This mount will use a threaded wood insert betwwen the tubes so a bolt can be used for retention. The 115-175 does not extend past the edges of the tubes so I have some other options on the way.

5x7 11-12-2019 07:09 PM

1 Attachment(s)
Last, Erockets also had a 24mm interchangeable mount for the four fin 225 tube on clearance and it should work with the Laser-X. I got some additional cooling vanes so plan to mount a section of 29mm tube on the 24 mm tube and I’ll mount the Cooling vanes on it so it will look ldentical to the 29 mm mount when installed.

PaulK 11-16-2019 07:19 AM

I might have an original water-slide decal set for this, if you're interested. The last time i built one of these, I made my own decals to match the 1969 catalog illustration.

My favorite flight combo is 4xC6-3, though the Estes 29mm BP motors make for a good flight too.

5x7 11-17-2019 08:48 AM

Originally Posted by PaulK
I might have an original water-slide decal set for this, if you're interested. The last time i built one of these, I made my own decals to match the 1969 catalog illustration.

My favorite flight combo is 4xC6-3, though the Estes 29mm BP motors make for a good flight too.

If you find the decal, I would love to buy it, it would solve the white border of the vinyl decals and the wrong color of the Experimental decal. Please let me know if you locate it.

What do you think of the launch lug size? I have some 1/4” lugs I can substitute.

PaulK 11-17-2019 08:39 PM

1 Attachment(s)
I found the decals. If you can use them, I’ll mail them to you NC, just pm your address. It’ll be nice to see them put to use. A couple notes, though: they’re original Semroc (Pre-eRockets), and are laser printed. This gives them a dull sheen, and easy to scratch, so must be clear coated before use (I recommend liquid decal film). They’re printed on clear decal paper, so will *only* show up well on white.

5x7 11-18-2019 05:13 AM


All times are GMT -5. The time now is 01:54 PM.

Powered by: vBulletin Version 3.0.7
Copyright ©2000 - 2020, Jelsoft Enterprises Ltd.