# ThunderBeast II, 2-Stage build thread

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#### smashburn

##### Well-Known Member
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:

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

Steve Mashburn
tahomarocketworks.com
Tacoma WA

#### FredA

##### Well-Known Member
You need more power!
Use a 4" central with four 54mm "effect" motors.....

Have fun!

#### smashburn

##### Well-Known Member
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 .

Thanks!

#### smashburn

##### Well-Known Member
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!!

Last edited:

#### smashburn

##### Well-Known Member
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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#### smashburn

##### Well-Known Member
Some more fin work on the sustainer .. love the smell of Epoxy in the morning!

#### smashburn

##### Well-Known Member
Got home early and was able to finish up the fin assembly, for the most part. Still going to add some braces, eye bolts for deployment, etc but looking good so far. Next up the Booster fin assembly!

#### smashburn

##### Well-Known Member
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.

#### steveh.jae

##### Well-Known Member
TRF Supporter
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

#### smashburn

##### Well-Known Member
Smashburn
Here's a link to the project. Unfortunately all the photos are missing as that website no longer exists. I think I have them somewhere backed up .. it's a pretty good read anyway.

#### steveh.jae

##### Well-Known Member
TRF Supporter
Here's a link to the project. Unfortunately all the photos are missing as that website no longer exists. I think I have them somewhere backed up .. it's a pretty good read anyway.

Thanks!

#### smashburn

##### Well-Known Member
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!

#### BDB

##### Absent Minded Professor
What kind of plywood did you use for the fins? My daughter and I are starting to work on a sonotube project too.

#### smashburn

##### Well-Known Member
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!

#### prfesser

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 #### mrwalsh85 ##### Well-Known Member 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. #### smashburn ##### Well-Known Member 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!

#### smashburn

##### Well-Known Member
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.

#### blackjack2564

##### Crazy Jim's Gone Banana's
TRF Supporter
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

##### Well-Known Member
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!”

#### smashburn

##### Well-Known Member
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.

BDB