Mean Machine baffle

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Screaminhelo

Shade Tree Rocket Surgeon
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I finally got started on my Mean Machine and wanted to put in a baffle. My question is , where do y'all prefer to locate it? Lot would be plenty far from the motor if I put it at the first joint and I am wondering if putting it at the last joint (closest to the NC) may introduce a little more of a mass moment than preferred. Are these valid questions here or am I over thinking this?
 
Hi Bill. Thanks for starting this thread. I've got some interest in the answers you'll be getting.

I'm planning on putting a baffle in my 3/4 Mean Machine (bought on ebay some time ago and when it arrived, one of the body tubes was crushed beyond use). I'd like to put the baffle at the first joint and mount the recovery system at the second joint. I think pressurizing the smaller volume of just two tubes instead of all four (or three in my case) will assure more reliable ejection of the chute. It will also make transportation easier especially when I build another kit with all the tubes.

I've seen many example of the recovery break coming at the mid-point and at the nose cone. I have to say the sight of the whole length of the rocket coming down as a unit under the chute is impressive but I've seen lots come back with the NC just dangling a little bit out of the top of the fourth body tube and the chute still inside.

I'll be keeping an eye on this thread to see if anyone has had direct experience with a baffle in the MM. I hope we get some good information.
 
If I had to choose, I would use the second or middle joint. That way you could also incorporate the shock cord mount into the baffle.

Think I would try it like this. <nose cone =coupler

<top tube=second tube= coupler baffle=third tube=fourth tube

Make the nose cone and top tube sealed and separate as one, second tube area is recovery bay.

I've wanted to build a Mean Machine. Just too many other projects going.

Might have to start one after AIRFest.

See ya,
Rod
 
I am using the supplied plastic coupler so that I can break it in half for transport to the range. I may piece it together and check the CG with the baffle at both locations to see how much the baffle location affects the balance.
 
so make the baffle out of 1/8 ply and (CA) glue one piece to each of the plastic couplers. Prudent positioning would allow you to replace them easily if necessary.
 
so make the baffle out of 1/8 ply and (CA) glue one piece to each of the plastic couplers. Prudent positioning would allow you to replace them easily if necessary.

I like the idea! Unfortunately, I have already epoxied the plastic coupling halves in place. Looks like I will just play with the balance and see if it makes a difference worth worrying about.
 
Or use no baffle. I had one plug up after many uses of caps , plugs, and tape.Didnt have enough pop to get chute out on a loc magnum and stuffed it into the ground. I would never use a baffle again.
 
The two I built, I left out that plastic coupler and made a bulkhead out of one of the paper couplers and some foamcore coated with epoxy. I put that in the middle, between the second and third body tubes, so it essentially had a two body tube length payload compartment. I put the baffle (four half moon semi-disks rotated a quarter turn from each other) inside the lowest coupler between the first and second body tube. Even with the baffle there and the chute in the second tube, both flew straight as an arrow (first had a 29mm mount and flew on an F motor). Pity neither came home (first one driftnet over some trees and couldn't be found, second draped itself over a power line).
 
Or use no baffle. I had one plug up after many uses of caps , plugs, and tape.Didnt have enough pop to get chute out on a loc magnum and stuffed it into the ground. I would never use a baffle again.

+1
I have witnessed this happen on more than one occasion in friends Aerotech kits, both times buried it to the fin can. :sigh:
 
I have done baffles before. In my Leviathan, I put it into the coupler. I regretted this as it moved the CG down, thus I had to add nose weight. I imagine that is not a big issue on the MM though. In the MM, I would suggest the half moon type of baffle. But make sure you keep the half moon discs fairly close to each other (compared to putting one disc per coupler), or the system will be less effective.

AT baffles use the "pot scrubber" steel wool which acts like a filter. All filters get plugged and require cleaning/replacement after significant use.
 
I made my baffle and tried it out both fore and aft. Without a motor, the baffle placement changes CG by less than 1/2" so I decided to place it forward. Yes, it may not work but the worst that can happen is a lawn dart. I am willing to accept the risk of failure and learn from the experience.

The wheels are already turning to add a stuffer and boattail to the design. I think that I could end up being a super roc fan.

Here are a couple pic of the finished baffle and the templates I made in Sketchup for the plates.
photo 1.jpgphoto 2.jpg

I can't attach the Sketchup file right now. Send a PM if you are interested.
 
I made my baffle and tried it out both fore and aft. Without a motor, the baffle placement changes CG by less than 1/2" so I decided to place it forward. Yes, it may not work but the worst that can happen is a lawn dart. I am willing to accept the risk of failure and learn from the experience.

The wheels are already turning to add a stuffer and boattail to the design. I think that I could end up being a super roc fan.

Here are a couple pic of the finished baffle and the templates I made in Sketchup for the plates.
View attachment 179859View attachment 179860

I can't attach the Sketchup file right now. Send a PM if you are interested.

Did the baffle in my MM similar to yours and it works just fine.

Here is the build thread:

https://www.rocketryforum.com/showthread.php?56599-Estes-Mean-Machine-w-mods-Build

Cheers!!
 
Thanks for the link! That's pretty much what I plan for round 2. I am actually pondering a stuffer that continues past the QD coupler but if you have had no problem with your set up, the only reason to do it is to see if it works.

I just need to work on my platform so I'll have something to launch from. I got a bunch of .30cal cleaning rods that I plan on using to make a 2 piece launch rod with.
 
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