29 mm Mean Machine

I guess that makes it a Meaner Machine:dark:.

I am well into the build of my Estes Mean Machine with a 29mm motor mount. I used the core from a roll of aluminum foil for the motor mount tube. It is a perfect fit. I used the stock centering rings just re-cut for a larger motor tube. Since the aluminum foil tube is not purpose built and I began to have doubts about its structural integrity I wrapped it in a single layer of 2 oz fiberglass cloth.

After gluing and filleting the fins I noticed that there is a ton of side-to-side flexibility in the fins. When I put some side pressure on the fins the body tube flexes allowing considerable side motion of the fin. I used a 12" long motor mount tube with only two centering rings, one close to each end. Next time I will add a third ring just behind the leading tip of the fins to stiffen the body tube from inside. I am also going to tip-to-tip glass the aft section of the body tube and fins. I recall a thread in here about somebody's 29mm Mean Machine disintegrating under the load of a G71R.

Lessons learned so far:

• Glass the body before gluing on the launch lugs :gavel:.
• Bonding resin is meant to be used in a well ventilated area, not my dining room:bangpan:.
• There is a reason why the Estes kit places the centering rings close to the fins:confused2:.

I didn't glass mine and it flew fine on an F20-7. The mods I made were:

* 29mm motor mount (from Apogee, I think)

* put a baffle in the first tube coupler

* broke it at the second coupler and put foamcore bulkheads in that coupler to form a payload bay. I left off the "quick connect" that came with it and just used another CT-60 coupler instead.

* replaced the chute with nylon

Flew straight as an arrow, and deployed perfectly - pity I lost it in the woods!

The thread about it is here:

https://www.rocketryforum.com/showthread.php?t=8534&highlight=machine

Having not done it, I'm not the biggest expert. However, I have build a successful short, BT60, 29mm rocket (without glass or any extreme reinforcement) and have shredded a long BT-50 rocket on a composite D. So, that experience says the smallish MM fins will be OK, the MMT will be OK, but buckling of the airframe may do it in. Make sure all the sections are well aligned! Couplers are often the weak point in airframes, but I don't know if this holds true with Estes components.

I have heard of a successful 29mm MM but don't remember the construction details. I look forward to your results!

Mine worked fine on an F20 and did not buckle - I just made sure all the tubes were straight and the couplers seated properly. Oh yeah - I did paper the fins with Avery Label stock and extended the label stock about 1/2" past the fin over the fillet. As I said, the flight was arrow straight with no wobble.

I think John Coker did his mean machine with a 29m & dual deploy.

gpoehlein said:

Mine worked fine on an F20 and did not buckle - I just made sure all the tubes were straight and the couplers seated properly. Oh yeah - I did paper the fins with Avery Label stock and extended the label stock about 1/2" past the fin over the fillet. As I said, the flight was arrow straight with no wobble.

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I hear ya', but try it on a G64, etc.

Sgt Blowfly said:

I think John Coker did his mean machine with a 29m & dual deploy.

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https://www.jcrocket.com/meanmachine.shtml

rstaff3 said:

https://www.jcrocket.com/meanmachine.shtml

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That is awesome!

There is so much unallocated space int he body tube which is just screaming to be used for some sort of payload. I like the mid-body coupling. The Mean Machine I built in my previous rocketry career (1985) was built as one solid piece. This bayonet coupling just opens so many possibilities.