MMX AGM-12B Bullpup

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Peartree

The basis for this model was John McCoy’s MMX plan sheet found on the MMX Yahoo group. I made a few modifications to John’s plans because I didn’t know where to find all of the parts and I don’t have the tools to make my own. I can’t turn nosecones so I went shopping and found one that looked darn close from Fliskits. I also did not have a tail cone and could not find anything commercially made that would work. Instead I used the available dimensions and fabricated the large and small diameters from balsa and cut a paper transition using the transition tool found on EMRR.

MMX Bullpup Parts (small).jpg

In the picture you can see the tail cone and engine mount as well as the other parts ready for assembly. I did not have ready-made centering rings, so I made those too again using the CR tools on EMRR. A caution here, these things are seriously tiny. Balsa simply will not let you cut it this small and hold together. Each piece had to be papered on both sides AND coated with thin superglue in order to be shaped and sanded. This was a lot of work and from now on I will spend the money to buy these parts whenever possible. The fins are also a little difficult to work with because of their size, but papering both sides allowed me to work with them without major hassles.

After assembling the rocket and many, many coats of Testor’s paint (sand, paint, repeat), I took the plunge and tried my hand at making my own decals. John McCoy had the format on the MMX Yahoo group but acquiring the needed materials, adapting the plan to use what I had available, learning how to print on decal paper, sealing it and then getting everything applied was a definite challenge for a first-timer. I thought it turned out pretty decent.

MMX Pullpup2 (small).jpg

I actually finished this for the Cleveland regional (GLRMR) this Spring (2008) and entered it in the Sport Scale competition (again, my first time). I did pretty well but didn’t have the nose weight right, it went unstable off the pad and I didn’t have time to fix it. A few weeks later, I entered it as my sport scale entry in the Columbus regional (MMRR). This time with an additional gram of nose weight, it flew fine and I came home with third for sport scale against Patrick Peterson and Chan Stevens from QUARK. I felt pretty good.

For a tiny model, I spent a lot of time getting things right and honestly both times I entered it, the judges were a bit surprised to judge something so small. Some details just were not done. Sanding fin profiles would have been just about impossible at the time but since then I picked up a set of tiny files that might help on the next MMX project. Overall, I had a great time building and flying this model and I’m sure that I will be building more of these wee beasties in the future.

MMX Bullpup Size (small).jpg
 
that's a pretty good down scale, down scales are more difficult that up scales, especially with decals. Good work
 
Great looking job John!
Glad The One-Page plan was of help.
Micro Scale does have it's unique challanges. did you add the fin tip folds? a simple thing that can add a lot to flght points as it introduces the roll of the real vehicle and model alike.
Also the tail-cone really isn't a ture cone as the full size vehicle has sort of a clamshell oval back there. I turned mine to the rough dimensions than hand filed & sanded in the high spot ridges. If you do this kind of detailing it's important to point out these type details to the judges in your data packet under construction notes, as well;)

You can never complain if you Place in the metals:) great to hear it was scored well.

Centering Rings:
OH man!!1 I just purchased my second 100 T2+-T3 laser cut centering rings from Fliskits... They are FANTASTIC!!!
but, If you don't want to purchase the currently available Wonderful selections from either Fliskits or Totally Tubular, which are mostly laser cut fiberboard.
I'd suggest using Heavy cardstock for your centering rings. I've used the backs from paper pads, file folders and even sho-card for cutting rings with compass type circle cutters. Wood is just not aa good idea even in 1/64 or 3/64th lite-ply you'll be working yourself to death!! ;)

Just as a side note for next time: you'll find it's not nearly as difficult to turn your own parts out of Basswood as it is in Balsa. even if your using a bench mounted hand drill as your lathe. One of the many "Home Shop" projects and demos I've done for my club was on "Home Made Lathes" using a cheapy hand drill as the starting point motor. I've since turned some pretty darn tiny parts on this 1/2" plywood/ hand drill comtraption. If your interested drop [email protected] a line I'll try to find and upload you the demo file and How-to pics for making your own:)

Launch stability with micros is always a challange, because of differences in material density and other factors you can build two identical micro models, one well fly just fine while the other will go unstable. I've also had Stable models in 5 -8mph winds wind up unstable in 12mph breezes??? it's almost maddening!!!! I've started posting "Swing TEST Before Launch" on all my micro plans. as changing the mass by our choice of materials slightly can really affect the flights.
My Bull-Pup 12B has about 8 flights in various wind conditions, It has so far been stable in all but one where the breeze was kicking up to almost 20mph at the time the button was pushed.

Great job, keep up the great micro work...... OH! don't forget Naram-51 has Peanut Sport Scale slated for next year as well:)

Circle cutters-a-sm_beam, and 2 compass types.jpg
 
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