Scratch-built Swarm Clone

[John Kemker]

I'm seriously considering building a scratch-built Swarm clone. I've got someone laser-cutting fins for me and I'm looking at options for nosecones, airframe, MMTs, etc.

At one point, I was considering building it all out of fiberglass, but the price was well over $500 for parts. I'm not real keen on cardboard tubing. That leaves phenolic kraft paper tubing and Blue Tube. I'm familiar with phenolic, having built rockets from it in the past. Not familiar with Blue Tube, but it looks promising, coming in at less than half the cost of FG.

I'll probably buy parts a bit at a time, until I have everything together.

For those that have used Blue Tube, is 'glassing the airframe useful for something that will probably only see a 1750NS K and 12 X G motors? or, would it be a bit overkill?

 

[cwbullet]

I'm seriously considering building a scratch-built Swarm clone. I've got someone laser-cutting fins for me and I'm looking at options for nosecones, airframe, MMTs, etc.

At one point, I was considering building it all out of fiberglass, but the price was well over $500 for parts. I'm not real keen on cardboard tubing. That leaves phenolic kraft paper tubing and Blue Tube. I'm familiar with phenolic, having built rockets from it in the past. Not familiar with Blue Tube, but it looks promising, coming in at less than half the cost of FG.

I'll probably buy parts a bit at a time, until I have everything together.

For those that have used Blue Tube, is 'glassing the airframe useful for something that will probably only see a 1750NS K and 12 X G motors? or, would it be a bit overkill?

Glassing Bluetube is overkill. It will shrink and swell so be prepared.

 

[John Kemker]

Glassing Bluetube is overkill. It will shrink and swell so be prepared.

Okay, so no glassing.

 

[teepot]

I like Blue Tube. Easy to cut with my miter saw. Tough as diamonds. It's original use is for artillery shells, IIRC. That is why it is in short supply. The only down side it is heavy. But that's why it is so strong.

 

[bad_idea]

Glassing Bluetube is overkill. It will shrink and swell so be prepared.

I thought taming that dimensional change - at least taming its maximum - was why people glassed it.

 

[Neutronium95]

I used to be a Blue Tube diehard, until one of my rockets warped a bit. If you live in the desert, you might be fine, but if you live in a humid area, look out for distortion. It's not just bending that's a concern, I've also heard of couplers swelling, and fitting fine one day, but needing tons of sanding to fit at the launch site.

I don't think that any of the intermediate tube materials between cardboard and fiberglass are very compelling options. Regular cardboard is great, provided you stay within its limits. Blue Tube is fine, except for the dimensional stability issues. Quantum tubing has enough stories that I won't touch it. Kraft Phenolic tubing is too brittle. I used it once, for my Jr. L1 and won't use it again. And while I've heard that Canvas Phenolic is great, it's almost as expensive as filament wound fiberglass.

If you're planning on glassing it, just go with cardboard or phenolic as the base tube.

 

[loopy]

I used to be a Blue Tube diehard, until one of my rockets warped a bit. If you live in the desert, you might be fine, but if you live in a humid area, look out for distortion. It's not just bending that's a concern, I've also heard of couplers swelling, and fitting fine one day, but needing tons of sanding to fit at the launch site.

I don't think that any of the intermediate tube materials between cardboard and fiberglass are very compelling options. Regular cardboard is great, provided you stay within its limits. Blue Tube is fine, except for the dimensional stability issues. Quantum tubing has enough stories that I won't touch it. Kraft Phenolic tubing is too brittle. I used it once, for my Jr. L1 and won't use it again. And while I've heard that Canvas Phenolic is great, it's almost as expensive as filament wound fiberglass.

If you're planning on glassing it, just go with cardboard or phenolic as the base tube.

Quantum isn't bad as long as it's not really cold. lol

 

[John Kemker]

Food for thought...

Thanks, guys! I appreciate the feedback/info. Dunno if LOC makes a 6" cardboard tube, though. Might have to run part of it 'glass, then the rest cardboard.

 

[jmasterj]

Dunno if LOC makes a 6" cardboard tube, though.

They do not.

 

[John Kemker]

They do not.

I didn't think so. So, maybe a fiberglass or glassed phenolic airframe with cardboard for everything else.

 

[mrwalsh85]

I don't understand everyone's apprehension to cardboard. I do like fiberglass, but I also enjoy building with cardboard tubes - whether glassed or not.

 

[John Kemker]

I don't understand everyone's apprehension to cardboard. I do like fiberglass, but I also enjoy building with cardboard tubes - whether glassed or not.

Not particularly averse to cardboard, but I like the ruggedness and ease-of-finish (less sanding) of fiberglass.

 

[mtnmanak]

I have a Swarm - the 6" tubing Jerry used looks very similar to the PML phenolic tubing:

https://locprecision.com/collection...enolic-airframe-tubing?variant=40843611275455
I don't think LOC carries the 6" nosecones for the 6" PML tubing anymore, but I seem to remember that the Wildman FG 6" nosecones/couplers fit in the PML 6" phenolic. I would check with LOC to verify.

You can also get the PML tubing pre-glassed if you are looking for the ultra-smooth finish.

Doing the whole project in Wildman 6" FWFG tubing may actually be lighter than the carboard/phenolic option.

 

[John Kemker]

I have a Swarm - the 6" tubing Jerry used looks very similar to the PML phenolic tubing:

https://locprecision.com/collection...enolic-airframe-tubing?variant=40843611275455
I don't think LOC carries the 6" nosecones for the 6" PML tubing anymore, but I seem to remember that the Wildman FG 6" nosecones/couplers fit in the PML 6" phenolic. I would check with LOC to verify.

You can also get the PML tubing pre-glassed if you are looking for the ultra-smooth finish.

Doing the whole project in Wildman 6" FWFG tubing may actually be lighter than the carboard/phenolic option.

I had a Swarm back in the early 2000s. It was cardboard tubing. NOT phenolic. Pretty ragged cardboard, at that.

If I go phenolic, I'll probably glass it myself. I've been looking at the Soller Composites fiberglass sleeves and their shrink-wrap tube. Of course, I'm filling the spirals, first.

Ken Allen @ Performance Hobbies has an elliptical listed on his site. I'm going to ask him if he's got any stashed away or can lay one up for me. The Swarm I used to have had an elliptical NC, not ogive.

 

[3stoogesrocketry]

Food for thought...

Thanks, guys! I appreciate the feedback/info. Dunno if LOC makes a 6" cardboard tube, though. Might have to run part of it 'glass, then the rest cardboard.

Yazoomills.com

 

[John Kemker]

Yazoomills.com

Almost $80 for 4 tubes at 6" X 24"!

 

[3stoogesrocketry]

Almost $80 for 4 tubes at 6" X 24"!

PML $57 dollars for 48 inches
Fiberglass from Tim $56 dollars per foot
Blue tube $78 dollars for 48 inches.

Have you looked lately what 12x SU G motors and a 1750 NS K motors run lol.

 

[John Kemker]

PML $57 dollars for 48 inches
Fiberglass from Tim $56 dollars per foot
Blue tube $78 dollars for 48 inches.

Have you looked lately what 12x SU G motors and a 1750 NS K motors run lol.

Oh, I know! (1750 NS K is going to cost me $89 for the reload. $200 for the case. I can then make my own reloads.)

I'm still ruminating on this project. Haven't spent any money, yet.

 

[sharkbait]

Oh, I know! (1750 NS K is going to cost me $89 for the reload. $200 for the case. I can then make my own reloads.)

I'm still ruminating on this project. Haven't spent any money, yet.

Please let me know where you are getting 4 grain K’s for $89.00

 

[John Kemker]

Please let me know where you are getting 4 grain K’s for $89.00

1) I never said it was a 4 grain K.
2) If I told you, it might not be available for me.

 

[mtnmanak]

I had a Swarm back in the early 2000s. It was cardboard tubing. NOT phenolic. Pretty ragged cardboard, at that.

If I go phenolic, I'll probably glass it myself. I've been looking at the Soller Composites fiberglass sleeves and their shrink-wrap tube. Of course, I'm filling the spirals, first.

Ken Allen @ Performance Hobbies has an elliptical listed on his site. I'm going to ask him if he's got any stashed away or can lay one up for me. The Swarm I used to have had an elliptical NC, not ogive.

Agree - it wasn't phenolic - just thick cardboard, but it looked a lot like the PML phenolic tubes, albeit rougher, as you noted.

I wish I knew where Jerry had gotten his tubes and nosecones, they were unique. His 12" stuff was actually 12.5", which was nice because it opened up some cool cluster possibilities. The PML and Composite Warehouse tubes are ~11.5". That 1 inch difference prevents a 5 x 98mm cluster. Of the many things I wish I had gotten from Jerry while he was still around, the unique tubing/nosecones are high on my list.

 

[StreuB1]

Normal LOC kraft tubing with a single FG soller sleeve would be cheap, easy to do, and very very strong.

I would go that route.

 

[sharkbait]

Normal LOC kraft tubing with a single FG soller sleeve would be cheap, easy to do, and very very strong.

I would go that route.

No 6” Loc
Would have to go Blue Tube or PML (Loc) phenolic.

 

[StreuB1]

No 6” Loc
Would have to go Blue Tube or PML (Loc) phenolic.

5.5" isn't close enough?

 

[John Kemker]

5.5" isn't close enough?

Nope. The Swarm has a 3" diameter center motor mount, with 12x29mm surrounding mounts. If you scale to 5.5" OD for the main airframe, the central motor mount becomes 2.75" rather than 3" and the 29mm mounts change to something else, as well. It's a sweet-spot airframe size for the design.

 

[Rocketjunkie]

My Motoreater uses 5.5" LOC tube. It has a 54 and 8 29 mm mounts. Been flying since 1990 and has 75 altimeter flights on it ranging from a single J460 to a K1100 and 8 H motors. I do have to replace the booster body tube every 15-20 flights as it just frays and gets pretty beat up.

 

[John Kemker]

My Motoreater uses 5.5" LOC tube. It has a 54 and 8 29 mm mounts. Been flying since 1990 and has 75 altimeter flights on it ranging from a single J460 to a K1100 and 8 H motors. I do have to replace the booster body tube every 15-20 flights as it just frays and gets pretty beat up.

I've seen the Motoreater up close. I'm familiar with it. However, I'm trying to recreate the USR Swarm.

 

[Rocketjunkie]

I've seen the Motoreater up close. I'm familiar with it. However, I'm trying to recreate the USR Swarm.

Just giving an example. If you want a durable rocket, I've used LOC, glassed PML, Blue Tube, and G1, all in 5.5" diameter.
LOC: works well but needs replacing every 15-20 flights.
Glassed PML: heavier and the phenolic can crack under the glass with rough handling.
Blue Tube: Much more durable but not stable size. Shrinks over time. Any fits with other materials will require lots of sanding. 54 mm Deuce.
G12 fiberglass: Expensive and heavy but the most durable.
If I was building a 6" cluster rocket now I would use a main body of G12 and either all G10-G12 internals or wood and PML motor tubes.
The weight of a fiberglass rocket isn't a problem with all the high thrust motors available. Use a center motor that will give a safe flight and air starting the outboards will give a spectacular flight. Use electronic deployment in all cluster flights. PML and G12 are available in 6". Not sure about Blue Tube. PML is available from LOC.
Fiberglass airframe https://wildmanrocketry.com/collections/fiberglass-1/products/g12-6-0
Fiberglass nose cone https://wildmanrocketry.com/collections/nosecone/products/fnc6-0-5-1vk-fw-mt
Phenolic airframe https://locprecision.com/collection...enolic-airframe-tubing?variant=40843611275455
LOC apparently didn't carry over the PML nose cones which were hand layup in a mold fiberglass.

 

[John Kemker]

Just giving an example. If you want a durable rocket, I've used LOC, glassed PML, Blue Tube, and G1, all in 5.5" diameter.
LOC: works well but needs replacing every 15-20 flights.
Glassed PML: heavier and the phenolic can crack under the glass with rough handling.
Blue Tube: Much more durable but not stable size. Shrinks over time. Any fits with other materials will require lots of sanding. 54 mm Deuce.
G12 fiberglass: Expensive and heavy but the most durable.
If I was building a 6" cluster rocket now I would use a main body of G12 and either all G10-G12 internals or wood and PML motor tubes.
The weight of a fiberglass rocket isn't a problem with all the high thrust motors available. Use a center motor that will give a safe flight and air starting the outboards will give a spectacular flight. Use electronic deployment in all cluster flights. PML and G12 are available in 6". Not sure about Blue Tube. PML is available from LOC.
Fiberglass airframe https://wildmanrocketry.com/collections/fiberglass-1/products/g12-6-0
Fiberglass nose cone https://wildmanrocketry.com/collections/nosecone/products/fnc6-0-5-1vk-fw-mt
Phenolic airframe https://locprecision.com/collection...enolic-airframe-tubing?variant=40843611275455
LOC apparently didn't carry over the PML nose cones which were hand layup in a mold fiberglass.

Thanks, Tom! Your advice carries a LOT of weight! I'll probably go with fiberglass main airframe and main MMT, with phenolic for the outboards.

 

[mtnmanak]

LOC apparently didn't carry over the PML nose cones which were hand layup in a mold fiberglass.

They aren't carrying them all the time, but they are doing some runs of the nosecones once in a while. I got them to make two of the 11.41" nosecones for me last year. I asked Jay about them (and the 7.5" glass nosecones) recently and he said they were working on getting the molds refinished and hoped to have clarity on timing sometime soon.

But, if you want one right now, Wildman is pretty much your only game in town.