ThunderBeast II, 2-Stage build thread

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smashburn

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I've really been wanting to build a large 2-Stage project for a while. Every few years or so I try to build something large and extreme, though this time it has been 8 years. The last one was the Proton M Group Project with NCR in Colorado, a 3-stage, 18 motor mount beast with a stunning array of electronics. It was an amazing and incredibly challenging project. Not totally successful, but safe and mostly recovered intact and rebuildable .. always a good thing on extreme projects.

For this one I've scaled the complexity back and gone with a straightforward 2-stage approach. It'll be 10" diameter, 14' tall, 4 fins design. I'll have a 4" MMT in the Booster with a 3" in the Sustainer. I'm debating adding some 38mm MMTs around the 3" for effect, we'll see. I'll use 10" sonatube for the body, 1/2 ply for the fins, styrofoam for the nosecone, all fiberglassed. Final weight will of course determine final motors, though trying to keep it light. It will be low and slow for the most part, but quick enough off the pad to be very stable. Definitely no mach speed issues. Should be another fun one! Here's a rough design:

Beast-10in-2stage.jpg
Here's a shot of the Proton M from 2012 with some of the amazing team from Northern Colorado Rocketry!
16729361_10155829237298275_7942347658842836946_n.jpg

Steve Mashburn
tahomarocketworks.com
Tacoma WA
 
You need more power!
Use a 4" central with four 54mm "effect" motors.....

Have fun!
I probably will upgrade .. I always seem to 'build up' .. I can always adapt down if the situation calls for it. Unfortunately more power comes with a cost $$. o_O

Thanks!
 
Got the sonatube and fin material. Started cutting centering rings/bulkheads with my awesome router jig. Also did some layout for the fins and motors, 3" w/ 4-54's for the sustainer .. maybe :)

Will have the fiberglass, epoxy & MMT's this week and can really get things going.

Let the fun begin!!

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Got to working on the fins. These are the smaller sustainer fins. I cut them close and then bolt them together. My handheld belt sander does a great job squaring them uo to each other. Next step will bevel the edges on the router table. Then sand to clean up. Looks like I likely won't have a launch to fly this at until the October OROC launch. So I have plenty of time to do it right. Will likely fiberglass them just in case I ever want to go 'faster', not something I usually do.
 

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Got both Fin Assemblies done and glassed another Sona Tube. Should finish the 3rd tube this weekend and get them sanded. Then it'll be time for the faring coat to make them pretty and smooth. Can't wait for that so I can then slot the tubes and really see how this it going to look .. and start working on the Interstage Coupler! Also have to design and build the nosecone .. I'm thinking going Conical since I almost always go Ogive .. time for a change and it should look pretty cool!!

The Simms are looking great using a CTI 98mm M3400 to CTI 75mm L851 configuration. Staging at 1000', 400 mph and apogee at 9900'. Of course everything depends on the final weight, I'm hoping for around 100 lbs on the pad.

IMG_1532.jpgIMG_1535.jpgIMG_1537.jpgIMG_1538.jpg
 
I've really been wanting to build a large 2-Stage project for a while. Every few years or so I try to build something large and extreme, though this time it has been 8 years. The last one was the Proton M Group Project with NCR in Colorado, a 3-stage, 18 motor mount beast with a stunning array of electronics. It was an amazing and incredibly challenging project. Not totally successful, but safe and mostly recovered intact and rebuildable .. always a good thing on extreme projects.

For this one I've scaled the complexity back and gone with a straightforward 2-stage approach. It'll be 10" diameter, 14' tall, 4 fins design. I'll have a 4" MMT in the Booster with a 3" in the Sustainer. I'm debating adding some 38mm MMTs around the 3" for effect, we'll see. I'll use 10" sonatube for the body, 1/2 ply for the fins, styrofoam for the nosecone, all fiberglassed. Final weight will of course determine final motors, though trying to keep it light. It will be low and slow for the most part, but quick enough off the pad to be very stable. Definitely no mach speed issues. Should be another fun one! Here's a rough design:

View attachment 422184
Here's a shot of the Proton M from 2012 with some of the amazing team from Northern Colorado Rocketry!
View attachment 422185

Steve Mashburn
tahomarocketworks.com
Tacoma WA
Smashburn
Tell us about the Proton M shot, please.
 
Slotting the first tube on the sustainer (2nd stage). Love this part! Will push the motor/fin assembly 3" up into the body to allow for the InterStage Coupler from the Booster. This is going to be pretty Beastly!

IMG_1561.jpg
 
What kind of plywood did you use for the fins? My daughter and I are starting to work on a sonotube project too.
I used the 1/2" sanded stuff from Home Depot this time. Not the best and is only 3 ply, but works ok. I used the same for the bulkheads and centering rings.

I'd prefer the 7 ply Aircraft or Cabinet grade plywood but have not found a local source for it yet. When I lived in Atlanta I found a great source where I could buy 1/2 sheets for a reasonable price .. it can be overly expensive. It definitely needs to be smooth on both sides.

Depending on how big the fins are you might get by with 3/8". Also, if you are going Mach, 700 mph +, you might have some other things to consider .. I never go that fast.

As you can see, I like big fins and I can not lie! I might have used 5/8" on these, I don't remember. It flew perfect!

Steve Mashburn at Freedom Launch 2007-2505.JPG
 
I used the 1/2" sanded stuff from Home Depot this time. Not the best and is only 3 ply, but works ok. I used the same for the bulkheads and centering rings.

I'd prefer the 7 ply Aircraft or Cabinet grade plywood but have not found a local source for it yet. When I lived in Atlanta I found a great source where I could buy 1/2 sheets for a reasonable price .. it can be overly expensive. It definitely needs to be smooth on both sides.

Some years ago I bought a type of plywood underlayment at Menards. I don't recall the brand but it was 1/4" 5-ply, actual was closer to 3/16" thick. One side was guaranteed clear, but the other side was clear or almost so on the sheets I looked at. I've used it for centering rings and fins for several rockets. It may have been the stuff they call PlyFloor ($20 for a 4x5' sheet, baltic birch), but I'm not sure. Anyway, two sheets glued together would give 10-ply, a bit over 3/8" thick.

Best -- Terry
 
If there is a Rockler near you, they should have 30" x 5' sheets, maybe even 5x5's of birch plywood. Not as cost effective but still good product.
 
Some years ago I bought a type of plywood underlayment at Menards. I don't recall the brand but it was 1/4" 5-ply, actual was closer to 3/16" thick. One side was guaranteed clear, but the other side was clear or almost so on the sheets I looked at. I've used it for centering rings and fins for several rockets. It may have been the stuff they call PlyFloor ($20 for a 4x5' sheet, baltic birch), but I'm not sure. Anyway, two sheets glued together would give 10-ply, a bit over 3/8" thick.

Best -- Terry
Thanks Terry, appreciate the idea, I'll give it a look. Really sweet getting input/feedback from a "legend" .. one of the great aspects of this hobby! Thanks for all you've done over the years!
 
If there is a Rockler near you, they should have 30" x 5' sheets, maybe even 5x5's of birch plywood. Not as cost effective but still good product.
Thanks Mike .. I do have one up by Seattle, but as you said it is a bit pricey. Ill still check it out next time I'm up there.
 
Smashburn I remember that rocket....I think I loaned u a 7600 case to fly a M-2200 skid in it at O'burg years ago...that was a hairy flight!
 
Smashburn I remember that rocket....I think I loaned u a 7600 case to fly a M-2200 skid in it at O'burg years ago...that was a hairy flight!
Yea, one of my favorite projects ever .. it flew perfectly and the Skid really added to the effect. Thanks for the loan, I loved that Orangeburg group!! Toms commenting was priceless too! “Catch Air .. Catch Air!”
02B5D69F-DC38-4C14-8B94-8943460960CE.jpeg
 
Not much free time lately, works been crazy, but got some more done on the Beast. Slotted both stages and started on the couplers/ebays.

BF3B13D0-1051-4AED-8CCE-0CA4496E7B66.jpeg
 
Got both Fin Assemblies done and glassed another Sona Tube. Should finish the 3rd tube this weekend and get them sanded. Then it'll be time for the faring coat to make them pretty and smooth. Can't wait for that so I can then slot the tubes and really see how this it going to look .. and start working on the Interstage Coupler! Also have to design and build the nosecone .. I'm thinking going Conical since I almost always go Ogive .. time for a change and it should look pretty cool!!

The Simms are looking great using a CTI 98mm M3400 to CTI 75mm L851 configuration. Staging at 1000', 400 mph and apogee at 9900'. Of course everything depends on the final weight, I'm hoping for around 100 lbs on the pad.

View attachment 424898View attachment 424899View attachment 424900View attachment 424901

Im curious how you fiberglassed the sonatube. One or multiple layers and the weight of cloth and type of resin that you used.

I’m scratch building a 6” diameter x 80” from already sturdy tube with 3/8” fins. I feel one wrap (of 6oz?) made it noticeably stiffer. Compression strength seems fine as I’m leaning more conservative on thrust and just trying to get it off the pad safety. But I have not tested for ejection charges. Have you or anyone else had issues with over pressure during deployment?

sebastian
 
Im curious how you fiberglassed the sonatube. One or multiple layers and the weight of cloth and type of resin that you used.

I’m scratch building a 6” diameter x 80” from already sturdy tube with 3/8” fins. I feel one wrap (of 6oz?) made it noticeably stiffer. Compression strength seems fine as I’m leaning more conservative on thrust and just trying to get it off the pad safety. But I have not tested for ejection charges. Have you or anyone else had issues with over pressure during deployment?

sebastian

Hi Sebastian!

I'm using 1 wrap of 6oz with West Systems Epoxy. After drying, I sand and bit and add a faring compound (West #407) pretty thick and spin it on a rotisserie (very slow rotation, made from BBQ grill rotisserie) so it doesn't run while drying. Not overly concerned about 'perfect' finish, 10' rule in effect. It beefs up the sona tube enough for my projects. Body tubes have never failed. Sand/primer/paint or fly naked. I never glass my fins, use heavy wood already, but do coat them with the Faring coat for a smoother finish. I add a lot of weight this way but that's not a concern for my projects.

Never had issues with ejection charges, and with a 2ft x 1ft area on the bigger ones I use a 'lot' of BP. Though with the outboards and main tubes ranging from 4" to 16" I've had no issues.

Note I never go Mach or anywhere close to it. I like low and slow theatrical flights. So if you are pushing those velocities find someone who has done that as well.

We've had some fairly epic failures (see Titan IV @ Whittakers & Proton @ NCR Colorado) and the body tubes were never the issue.

Good luck, and have fun!! :)

Steve
 
Finally back to work on the 'Beast.

Building the styrofoam nosecone. Turned some junk wood as a tip, mounted it in a 3" tube, and that into a coupler. Will cut rings of foam and shape them, then fiberglass over that. The 3" tube also has a door at the bottom so weight can be added into the 3" tube. We did this on the Delta II and it was a lifesaver because we needed more noseweight once we got it all assembled and motors loaded.

Next is the main coupler for the sustainer. It will have a uBolt, not the eye bolt, that's just for working on it. Will have a couple of RRC2's in there for Apogee and Main (500') deployment.

Last the the Interstage coupler. I prepped it for 8 rods, only had 4 cut so far. It will serve as the Booster nosecone once the Stage Separation occurs and also has RRC2's to deploy the main at it's apogee. The Stages will likely Drag Separate due to the much larger Booster fins, but the Marsa in the sustainer will also ignite a charge to force separation. The Marsa with Tilt Module will ensure vertical flight and proper altitude and then ignite the sustainer motor.

I'm looking at either Rocketober in October (OROC) or Sod Blaster in Sept (Tri-cities WA). To meet their site conditions, I'll launch on a CTI M2505 and stage to a CTI L585 for a combined M Class launch.

Anyone near Tacoma WA wanting to help out is welcome to join in. Guaranteed to learn something new. I will finish the build by mid-may as I'll be ramping up my Hot Sauce Biz for the Summer Markets.

Steve


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Finally back to work on the 'Beast.

Building the styrofoam nosecone. Turned some junk wood as a tip, mounted it in a 3" tube, and that into a coupler. Will cut rings of foam and shape them, then fiberglass over that. The 3" tube also has a door at the bottom so weight can be added into the 3" tube. We did this on the Delta II and it was a lifesaver because we needed more noseweight once we got it all assembled and motors loaded.

Next is the main coupler for the sustainer. It will have a uBolt, not the eye bolt, that's just for working on it. Will have a couple of RRC2's in there for Apogee and Main (500') deployment.

Last the the Interstage coupler. I prepped it for 8 rods, only had 4 cut so far. It will serve as the Booster nosecone once the Stage Separation occurs and also has RRC2's to deploy the main at it's apogee. The Stages will likely Drag Separate due to the much larger Booster fins, but the Marsa in the sustainer will also ignite a charge to force separation. The Marsa with Tilt Module will ensure vertical flight and proper altitude and then ignite the sustainer motor.

I'm looking at either Rocketober in October (OROC) or Sod Blaster in Sept (Tri-cities WA). To meet their site conditions, I'll launch on a CTI M2505 and stage to a CTI L585 for a combined M Class launch.

Anyone near Tacoma WA wanting to help out is welcome to join in. Guaranteed to learn something new. I will finish the build by mid-may as I'll be ramping up my Hot Sauce Biz for the Summer Markets.

Steve


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Interesting project, as for when we would enjoy having you at Sod Blaster IV this year, last year we had an N research and an N Dark Matter, a big two stage is something we have not had flown yet.
 
Interesting project, as for when we would enjoy having you at Sod Blaster IV this year, last year we had an N research and an N Dark Matter, a big two stage is something we have not had flown yet.
Thanks, I like the idea of Sod vs prairie, and Sept should have better weather .. Oct can turn fast.
 
Got the 'Beast outside and set up .. for a little perspective. No motors or chutes and a little framing left to do but weighed in at 43 lbs. Not bad. Still have to finish the nosecone shaping and glassing. I think I might need a bigger shed/workspace!

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Did you end up flying on the CTI M2505 and CTI L585 motor combination? What was your method for sustainer ignition?

My college team has a launch coming up where we're also staging to an L585 and I'm doing some last minute research to try and make sure we have successful ignition...
 
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