Meaner Machine scratch build

[qquake2k]

I've wanted to build a Mean Machine upscale for a while now. I played around with 3" and 4" designs, but the logistics were daunting. A 3" would be almost 12ft tall, and a 4" would be almost 16ft. While either would be very cool, they would be a pain to build and transport. I recently discovered three lengths of 2.56" LOC body tubes. Two are 34" long, and the third is 30" long. I don't remember buying them, and certainly don't remember what I had planned for them. Could have been a Mean Machine upscale, for all I know. Anyway, now they are for the Meaner Machine.

I am repurposing a nose cone from my nephew's crashed rocket. It's a short one, and with the 30" tube, it will work out to a little under 9ft. True scale would be a hair over 10ft, but I'm calling it good. I'll be painting it black and yellow, and the black will be satin instead of gloss. I've also reduced the fins to three, just to be different. It will be zipperless, and separate at the 30" tube, where the 29mm motor tube will be. The other two sections will also be able to separate, just in case I ever need to take it in my car.



View attachment Meaner Machine baffle.ork

 

[qquake2k]

The design calls for three centering rings for the motor tube; a baffle for one of the couplers; a bulkhead for the other coupler; and a bulkhead for the center body tube. I cut out the centering rings and one bulkhead with a 2-7/8" hole saw. I cut the baffle and coupler bulkhead with a 2-3/4" hole saw. As usual, I sized them on my lathe. I drilled eight 5/16" holes in the baffle. I got a few chip outs, but I'll fill those with epoxy. I had to size the baffle separately, because that coupler is a little thicker.

 

[qquake2k]

I wanted the bulkhead that goes into the forward coupler to be thick, because three screws will be screwed into it. So I laminated pieces of 3/8" and 1/8" plywood together, to make it 1/2" thick. I cut the holes for the motor tube with a 1-3/16" hole saw, and sized them with the Dremel. I also epoxied blocks onto two of them for the rail buttons.

 

[qquake2k]

I got the fins cut out of the 5mm birch plywood that I bought at Lowe's.

 

[qquake2k]

As usual, I pinned the fin blanks together with 1/4" dowels, so I could cut and match sand the fins together. I haven't used one before, but I decided to try an Estes 29mm retainer on this build. The price is certainly right.

 

[qquake2k]

I needed to trim the excess epoxy off the forward bulkhead, but the bolt I used to hold it together was stuck in it. I unscrewed it, drilled out the center hole, and mounted it on the lathe.

 

[K'Tesh]

Looks Good So Far!

I'll be watching this one... op:

 

[qquake2k]

Thanks K'Tesh!

 

[Bat-mite]

Cool. A word of advice if it's not too late: long, thin rockets really need longer couplers. Minimize the wiggle room around the couplers, and you'll get a much straighter flight. Have fun!

 

[BABAR]

I've wanted to build a Mean Machine upscale for a while now. I played around with 3" and 4" designs, but the logistics were daunting. A 3" would be almost 12ft tall, and a 4" would be almost 16ft. While either would be very cool, they would be a pain to build and transport. .

I have no experience with high power builds, but was wondering---- can you do high power tall rockets by building the rocket in "reasonably manageable" segments, say 3-5 feet long, that are transported individually and then reconstructed at the launch site? I guess you would need to link up the electronics wiring across the segments, and the couplings would have to be super strong.

 

[chris m]

Yes long coupler say twice as long

 

[chris m]

I would love to do one but to many irons in the fire now

 

[qquake2k]

Cool. A word of advice if it's not too late: long, thin rockets really need longer couplers. Minimize the wiggle room around the couplers, and you'll get a much straighter flight. Have fun!

Yes long coupler say twice as long

Short couplers weren't a problem with Stairway To Heaven.

[YOUTUBE]WzlrhaZLFBA[/YOUTUBE]

[YOUTUBE]ysJSYeztFLk[/YOUTUBE]

 

[qquake2k]

I trimmed a few inches off the long motor tube, for the shorter 30" aft body tube. Sanded the rail button blocks smooth, then epoxied the forward two centering rings on the motor tube. And as usual, I drilled pilot holes in the aft centering rings, for screws to pull it out with.

 

[qquake2k]

I put my signature messy fillets on the two centering rings, and epoxied the motor mount into the body tube.

 

[ksaves2]

Ground test the ejection with that baffle to make sure it works. Me thinks it might be too much of a restrictor to be effective. If you test then you'll be ok. Kurt

 

[qquake2k]

I've made quite a few baffles like this, and never had a problem with any of them. And most have half moon baffles in the forward ends of the motor tubes.

 

[qquake2k]

[YOUTUBE]pFQhXnQwcqY[/YOUTUBE]

[YOUTUBE]jyaBXD8GJOw[/YOUTUBE]

[YOUTUBE]WzlrhaZLFBA[/YOUTUBE]

 

[ksaves2]

I've made quite a few baffles like this, and never had a problem with any of them. And most have half moon baffles in the forward ends of the motor tubes.

Do you use less dog barf with it or just use a chute protector? Kurt

 

[qquake2k]

Do you use less dog barf with it or just use a chute protector? Kurt

I don't use either, if I have the half moon baffles in the motor tube.

 

[qquake2k]

I've made several 4" like this, and one 5.5", my Level 2 upscale Shadow XXL. They all worked flawlessly.

 

[ksaves2]

Thanks for the information. Kurt

 

[qquake2k]

I got the fin slots cut and did a dry fit. The fin tabs were a tad too short, but a little sanding took care of that. Using my handy dandy homemade fin alignment guide, I got the fins epoxied on. Then applied my usual lame but functional external fillets with Titebond no-run wood glue.

 

[K'Tesh]

Cap' I'm lost... If tabs are too short, how does sanding help?

Other than that, Looks Awesome!

 

[Lowpuller]

Nice work!

I make similar baffles, see my avatar!

Where do you get those nice plastic jaw protectors for your vice?

 

[qquake2k]

Cap' I'm lost... If tabs are too short, how does sanding help?

Other than that, Looks Awesome!

You don't sand the tabs, you sand the areas of the fin that will be epoxied to the outside of the body tube. That effectively makes the tab longer.

 

[qquake2k]

Nice work!

I make similar baffles, see my avatar!

Where do you get those nice plastic jaw protectors for your vice?

I've found that the Fin Guide Tool on Payloadbay is handy for marking the baffles. Input the ID of the coupler, 8 fins (or however many holes you want), then add a second circle in a drawing program. Where the circle intersects the fin lines, is where you drill the baffle holes. The center circle is the diameter of the motor tube.

https://www.payloadbay.com/index.php?page=Tools&action=FINGUIDES

I got the soft jaw protectors from Lowe's, but I don't think they have them anymore. They do, however, have them on Amazon.

https://www.amazon.com/dp/B0057PUEZO/?tag=skimlinks_replacement-20



View attachment baffle_drill (2).pdf

 

[K'Tesh]

You don't sand the tabs, you sand the areas of the fin that will be epoxied to the outside of the body tube. That effectively makes the tab longer.

Of course... I wasn't thinking about changing the exposed shape.

 

[qquake2k]

Of course... I wasn't thinking about changing the exposed shape.

It doesn't visibly change the exposed shape, unless the tabs were cut WAY short.

 

[qquake2k]

Got some messy internal fillets put in.