LOC Comet - Custom project for LDRS 37

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ThirstyBarbarian

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Last year I started a thread about ideas for an upscale of the Estes Silver Comet. https://www.rocketryforum.com/showthread.php?140705-Silver-Comet-Upscale

Well, today LOC Precision shipped me a custom LOC Comet! It's a 5.5" diameter, 60" tall, 3-fin, retro sci-fi design inspired by the Silver Comet and the rockets from early sci-fi movies, books, magazines, and art!

It should be arriving soon, and I'm planning to make this a build thread.

One of my local clubs is hosting LDRS 37 in May, and I want to have a special project to fly when I'm there. The LOC Comet will be it! I invite you to participate in the thread --- there may be some techniques I need help with. And, if you want to see the rocket in person, come out to LDRS in Central California this May 16 -20. https://ldrs37.org
 
Background:

I've always liked the retro-future look of rockets from pop-culture sci-fi of the 50's and 60's and earlier. When I returned to rocketry as a BAR, the first kit i built was a Silver Comet that I had picked up at a clearance sale a few years earlier. I like the retro-future style of that rocket, and it's inspired me to attempt similar 50's sci-fi looks on other rockets, like my Pod Rocket kit bash of the Mega Der Red Max.

Here is a Silver Comet. (Not mine, just a pic the from internet.)

silvercometside.jpg

And here is my Pod Rocket I built in retro-future style out of a MDRM kit:

MDRM-P-Finished1.jpg

There aren't really very many HPR kits with this kind of look to them, so if you want one, usually you have to kit-bash an existing kit or make something from scratch. I started to wonder what it would take to make something in this style form existing HPR kits on the market. The Estes Silver Comet kit is basically just a modified Estes V2 kit. It's a V2 kit with a swoopy fin pattern and a special nose cone molded with a canopy detail. It seems like it would be easy to kit bash an upscale comet-like rocket from any of the many HPR V2 kits on the market --- just cut a new set of fins, like Estes did. The other thread was about ideas for how to do that.

I thought about just ordering a V2 from a company like LOC and cutting the fins myself, but I am not really equipped to do that, so I kind of shelved the idea for about 8 months.

Now with LDRS coming, I decided this was going to be my LDRS project. I wasn't sure what kind of custom services LOC could provide, so I sent them an email outlining my project and asking if they could cut custom fins and custom tail cones, and they got back to me right away eager to help out!
 
Jay at LOC Precision helped me with this project and was great to work with!

One of the first questions was what size kit to work with. I considered a 7.5" kit but settled on a 5.5" diameter kit. 5.5" yields a kit about 60" tall from tip of nose cone to tip of fins. That's something I can store and can fly on my existing hardware. The 7.5" kit would end up over 7 feet tall, and would take some pretty big motors! Maybe if this one works out, we can go bigger later...

Jay asked for a fin design, and I sent him one. And I also asked if he could slot the tail cone for 3 fins, instead of 4. I think 3 fins looks better on this kind of sic-fi rocket and makes the paint schemes work better than they do for 4 fins. This is one of the reasons this rocket is not really a true upscale Silver Comet, but something unique.

Jay said that there would be 2 challenges for them to handle on their end. First, they usually laser cut fins in 1/4" Baltic birch. But the long, swoopy fins might not hold up very well, so he recommended 3/8 plywood instead. (And I should still probably glass them.) He said he would need to do some experiments to see if the laser could handle the 3/8 cleanly. And the second issue was that their CNC was set up to slot tail cones for 4 fins, and he would need to change a few things to slot for 3 fins. It was just a couple days later that he had all the technical challenges worked out, and we were good to go!

I sent him my choices for a few other items to finalize the order:


  • Nose and tail cones -- I decided on their longer 5.5" cones instead the shorter ones. This is another departure from the Silver Comet original and another reason this is really custom rocket, not a true upscale. Their long cone is longer that the upscale of the Silver Comet would be, and their short cone is shorter. I think the long cones and shorter midsection of airframe tubing will make for a more gracefully curving rocket, so I actually think I will prefer it. And of course the LOC nose cone does not have the molded canopy detail, and I think I will also prefer making my own design for the canopy with paint or decals, along with a different paint scheme overall.
  • Motor mount -- I selected a 38mm mount, because it will work with my existing hardware, and i think there will be plenty 38's that will work with the rocket, but the rocket could be built with a 54mm mount.
  • Electronics bay -- I decided against it. Everything I have ever flown has been motor eject, and I don't tend to fly very high or aggressively, especially with rockets I put a lot of work into detailing. Plus, the main feature of the rocket will be its looks, and I don't need more breaks in the tubing.
  • Rail guides -- 1500 series rail buttons
  • Recovery -- 60” chute, 18” x 18” fire resistant blanket, 25’ tubular nylon with sewn ends, 2ea 4’ tubular nylon from Ubolts to main tubular, 2ea Ubolts, 4ea quick links
  • Motor retainer -- LOC was out of 38mm Aeropack, so I will buy it separately.

Here are some pics Jay sent me during the process of prepping the parts.

Nifty shot of a centering ring and MMT in the tail cone.

centering-rings.jpg

Tail cone with 3 slots.

slots.jpg

Dry fit of the 60" LOC Comet compared to a 28" stock Silver Comet.

dry-fit.png
 
Very nice Thirsty, watching with interest. Have you given any thought to siming this beatie ? I did see an .rkt file for the Estes kit on Rocketreviews

https://www.rocketreviews.com/unknown-silver-comet.html

Thanks! I will check out the file. I have OR, not Rocsim. I remember trying to sim the Silver Comet in OR a few years ago, and it didn't support the tail cone or the fin shape. Maybe there are some upgrades now, and it will work. I'd definitely like to be able to sim it for flight profiles, motor selection, and estimating delays. And it would be great to get a good CP estimate so I can be sure it is stable with the final CG.
 
FedEx tracking says the kit will arrive on Feb 15, so it looks like my sweetie pie is going to have to get me something else for Valentines Day, and she better make it something GOOD!
 
FedEx tracking says the kit will arrive on Feb 15, so it looks like my sweetie pie is going to have to get me something else for Valentines Day, and she better make it something GOOD!

Maybe she can get you a Aeropack retainer...
 
I seriously like the look of the LOC Comet. I wonder if LOC will offer it as a kit. I bet it would be popular. And good call on the 38mm mount. A nine grain J575 would give it a nice ride.
 
Jay at LOC Precision helped me with this project and was great to work with!

One of the first questions was what size kit to work with. I considered a 7.5" kit but settled on a 5.5" diameter kit. 5.5" yields a kit about 60" tall from tip of nose cone to tip of fins. That's something I can store and can fly on my existing hardware. The 7.5" kit would end up over 7 feet tall, and would take some pretty big motors! Maybe if this one works out, we can go bigger later...

Jay asked for a fin design, and I sent him one. And I also asked if he could slot the tail cone for 3 fins, instead of 4. I think 3 fins looks better on this kind of sic-fi rocket and makes the paint schemes work better than they do for 4 fins. This is one of the reasons this rocket is not really a true upscale Silver Comet, but something unique.

Jay said that there would be 2 challenges for them to handle on their end. First, they usually laser cut fins in 1/4" Baltic birch. But the long, swoopy fins might not hold up very well, so he recommended 3/8 plywood instead. (And I should still probably glass them.) He said he would need to do some experiments to see if the laser could handle the 3/8 cleanly. And the second issue was that their CNC was set up to slot tail cones for 4 fins, and he would need to change a few things to slot for 3 fins. It was just a couple days later that he had all the technical challenges worked out, and we were good to go!

I sent him my choices for a few other items to finalize the order:


  • Nose and tail cones -- I decided on their longer 5.5" cones instead the shorter ones. This is another departure from the Silver Comet original and another reason this is really custom rocket, not a true upscale. Their long cone is longer that the upscale of the Silver Comet would be, and their short cone is shorter. I think the long cones and shorter midsection of airframe tubing will make for a more gracefully curving rocket, so I actually think I will prefer it. And of course the LOC nose cone does not have the molded canopy detail, and I think I will also prefer making my own design for the canopy with paint or decals, along with a different paint scheme overall.
  • Motor mount -- I selected a 38mm mount, because it will work with my existing hardware, and i think there will be plenty 38's that will work with the rocket, but the rocket could be built with a 54mm mount.
  • Electronics bay -- I decided against it. Everything I have ever flown has been motor eject, and I don't tend to fly very high or aggressively, especially with rockets I put a lot of work into detailing. Plus, the main feature of the rocket will be its looks, and I don't need more breaks in the tubing.
  • Rail guides -- 1500 series rail buttons
  • Recovery -- 60” chute, 18” x 18” fire resistant blanket, 25’ tubular nylon with sewn ends, 2ea 4’ tubular nylon from Ubolts to main tubular, 2ea Ubolts, 4ea quick links
  • Motor retainer -- LOC was out of 38mm Aeropack, so I will buy it separately.

Here are some pics Jay sent me during the process of prepping the parts.

Nifty shot of a centering ring and MMT in the tail cone.

View attachment 338141

Tail cone with 3 slots.

View attachment 338142

Dry fit of the 60" LOC Comet compared to a 28" stock Silver Comet.

View attachment 338140

Very nice. The Silver Comet is one of my favorites also. I can see one of these in my future also, but I really want to go bigger.


Steve Shannon
 
Very nice. The Silver Comet is one of my favorites also. I can see one of these in my future also, but I really want to go bigger.

I originally thought about a 7.5” diameter, which would have meant a rocket around 7’ tall! That was a bit too much rocket for me, but Jay said LOC could do it, and I’d love to see someone else try it. LOC is making a new motor mount system, which starts with a 98mm hole, and you can use swappable LOC adapters to go to 75mm, 54mm, or 3x38mm. It looks pretty cool, but a bit above what I’m looking for. Maybe if this one turns out nice, someone will be inspired to go even bigger.
 
Maybe she can get you a Aeropack retainer...

Maybe I should send her a link...

I seriously like the look of the LOC Comet. I wonder if LOC will offer it as a kit. I bet it would be popular. And good call on the 38mm mount. A nine grain J575 would give it a nice ride.

I don’t know if they will offer it as a kit, but I agree it would be popular among people with a certain kind of taste in rockets. We’ll see if this build turns out good. If so, even if they don’t list it as a kit, the’ll Have the files and specs if anyone want to do a special order like I did.
 
Thanks! I will check out the file. I have OR, not Rocsim. I remember trying to sim the Silver Comet in OR a few years ago, and it didn't support the tail cone or the fin shape. Maybe there are some upgrades now, and it will work. I'd definitely like to be able to sim it for flight profiles, motor selection, and estimating delays. And it would be great to get a good CP estimate so I can be sure it is stable with the final CG.

Yeah, with OR holding at version 15.3 I think you're in the same boat now. I also think the removal of one fin and small profile changes you made will move your cp compared to that file. Just not sure which way or how much. :blush:
Maybe you can persuade TRFer Cabernut to take a look at this. If I remember correctly he's an OR developer.
 
Last year I started a thread about ideas for an upscale of the Estes Silver Comet. https://www.rocketryforum.com/showthread.php?140705-Silver-Comet-Upscale
Well, today LOC Precision shipped me a custom LOC Comet! It's a 5.5" diameter, 60" tall, 3-fin, retro sci-fi design inspired by the Silver Comet and the rockets from early sci-fi movies, books, magazines, and art!
It should be arriving soon, and I'm planning to make this a build thread.
Excellent. I loved that kit...and like the style of those rockets.
Been thinking of doing the Disney TWA Moonliner for years myself.
 
Thanks! I will check out the file. I have OR, not Rocsim. I remember trying to sim the Silver Comet in OR a few years ago, and it didn't support the tail cone or the fin shape. Maybe there are some upgrades now, and it will work. I'd definitely like to be able to sim it for flight profiles, motor selection, and estimating delays. And it would be great to get a good CP estimate so I can be sure it is stable with the final CG.

OR will likely kick back an error about fins attached to boat tails and delete the fins. I think that was my problem with the V2. You could attach them to the motor mount or a ghost bodytube section and get by. But you would have to redraw your fins. Just guessing. I haven't downloaded the file and looked at.

Nice looking indeed. You likely could get someone to 3d print something for the nose cone detail and just glue it to the side. Maybe even card stock and/or vinyl.

At 5.5" you have plenty of room in the nose for an electronics package. 38mm in that big of rocket leaves lots of room for a donut bay as well. Side access too. You could disguise it as an access hatch.

I have (at least) two ideas for bringing some 50's SciFi style rockets to life. I just always forget when I am looking for something to build.
 
Excellent. I loved that kit...and like the style of those rockets.
Been thinking of doing the Disney TWA Moonliner for years myself.

That Moonliner is a cool design. I remember going to the Tomorrowland section of Disneyland as a kid and being really excited about the rockets!
 
OR will likely kick back an error about fins attached to boat tails and delete the fins. I think that was my problem with the V2. You could attach them to the motor mount or a ghost bodytube section and get by. But you would have to redraw your fins. Just guessing. I haven't downloaded the file and looked at.

Nice looking indeed. You likely could get someone to 3d print something for the nose cone detail and just glue it to the side. Maybe even card stock and/or vinyl.

At 5.5" you have plenty of room in the nose for an electronics package. 38mm in that big of rocket leaves lots of room for a donut bay as well. Side access too. You could disguise it as an access hatch.

I have (at least) two ideas for bringing some 50's SciFi style rockets to life. I just always forget when I am looking for something to build.

I think I should be able to get a good enough sim for purposes of calculating the CP without the boat tail and by approximating the fin shape and area. That will help me balance the rocket and determine if nose weight is necessary. Then I can go back and add the measured CG and final weight as overrides.

For flight sims, the boat tail might add some to the altitude by reducing drag, and I'm not sure how I would estimate that if I can't add a boat tail to the file. I will probably use motor eject, so a good estimate of the delay would be really helpful. If all else fails, I can add a second or two to the delay recommended by the sim without the boat tail and use a smaller drogue and Chute Release to reduce the deployment stress if that turns out to be too long.

I'm leaning toward getting some vinyl cut for this project. Add a flight canopy, some portholes and hatches, some lettering, and other details. It's going to be a pretty big rocket, so it's big platform for design, and some nice details would really add to the look I think.
 
This looks like fun Eric. I know you already ordered it, but I'd think long and hard about adding a 54mm mount. AeroPack makes some great adapters for 54/38 and you can always adapt down, but you can't go up. 5.5" x 60" is perfect for a 54mm. There is a LOT more variety of motors available in 54mm too, long burn, skids, colors, etc.
 
This looks like fun Eric. I know you already ordered it, but I'd think long and hard about adding a 54mm mount. AeroPack makes some great adapters for 54/38 and you can always adapt down, but you can't go up. 5.5" x 60" is perfect for a 54mm. There is a LOT more variety of motors available in 54mm too, long burn, skids, colors, etc.

It does look like there are some great 54mm motors out there. Maybe I’ll regret it, but the package is passing through Salt Lake last I checked, so it’s pretty much a done deal. I’ll get to 54mm motors eventually, and electronics eventually, but for now, I’m trying to spread out my investment in the hobby a bit and use what I have.
 
It does look like there are some great 54mm motors out there. Maybe I’ll regret it, but the package is passing through Salt Lake last I checked, so it’s pretty much a done deal. I’ll get to 54mm motors eventually, and electronics eventually, but for now, I’m trying to spread out my investment in the hobby a bit and use what I have.

Great thread Eric! OH, and if you trim down the fin tabs....a new motor tube and rings would get you that 54mm :)

Can't wait to see her take shape! Have fun dude!

Jay
 
That's cool!

I love how responsive the manufacturers in this hobby are to custom requests. Keep up the good work, LOC! (and any other manufacturer paying attention to customer service!)
 
Great thread Eric! OH, and if you trim down the fin tabs....a new motor tube and rings would get you that 54mm :)

Can't wait to see her take shape! Have fun dude!

Jay

Thanks, Jay! I’m looking forward to getting this kit in my hands. I’ve been checking the tracking number daily, watching it make its way my direction. Looks like it’s coming on Thursday.

For everyone reading this thread, JAYatLOC is (you guessed it) Jay at LOC — the guy who helped me with this kit. Jay was very helpful and moved this custom order along very quickly, solving some issues on their end that hadn’t come up before, like the 3-slot tail cone. If you have some ideas for custom changes to LOC kits for a special project, I’d encourage you to ask them about it, because this turned out way easier than I thought it would be.
 
Hey Eric,

Cool thread, great idea, sweet rocket you're brewing there!

Can't disagree with the 54...but that 38 will be just fine regardless! The longer and thinner the tube, the faster the burn for a given impulse...lots of thrusty 38mm options out there!

Looking forward to reading along!
 
Well, I hate to volunteer to be cursed, but you can always adapt down. [emoji16]

LOL!

I think the kit will arrive tomorrow, so I will take a look at what I get and weigh everything. If it looks like it will be any heavier than my Warlock, then maybe I'll go for the 54mm. The long, swoopy fins may need some fiberglass to withstand landings, so this could end up heavier than most of my rockets.

And I do like the looks of some of the longer burning 54mm CTI loads...
 
I'm pretty sure Buck Rogers would agree that a long burn skid with lots of sparks is the proper motor for this project. Try finding that in a 38mm.

END OF DEBATE. LOL!

LOL!

I think the kit will arrive tomorrow, so I will take a look at what I get and weigh everything. If it looks like it will be any heavier than my Warlock, then maybe I'll go for the 54mm. The long, swoopy fins may need some fiberglass to withstand landings, so this could end up heavier than most of my rockets.

And I do like the looks of some of the longer burning 54mm CTI loads...
 
The kit has arrived form LOC Precision! It's time for the big reveal!

The box.

IMG_3608.jpg

The parts!

IMG_3610.jpg


They laser engraved this centering ring. Kind of a nice touch.

IMG_E3614.jpg


I'm not even sure what these rings are for. Looks like spares.

IMG_E3617.jpg


This recovery setup is going to be the most robust one I have ever had on any of my rockets. Two u-bolts in the forward centering ring, two heavy-duty quick links connect two 4-foot tubular nylon harness pieces to the u-bolts, other ends of the harness attach with another quick link to the 25-foot tubular nylon shock cord, another quick link attaches the chute, and there is an 18-inch chute protector.

IMG_E3616.jpg


Custom fins!

IMG_3619.jpg


Tail cone slotted for 3 fins!

IMG_3618.jpg


My baby is big!

IMG_3613.jpg


They threw in a t-shirt!

IMG_3615.jpg


How it stacks up next to the G-Force and the Warlock

IMG_3620.jpg
 
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