Mid power mach buster.

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Well-Known Member
Oct 11, 2002
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For awhile I've been wanting to do this. And if some of you guys are interested ? I'll do some post on how to build one of these things. Step by step. For now I'll just post the roc simms file on it Then you an give it a look and see what type of rocket I'm talking about. If I an keep this thing around 7oz. done. It should do some where around 800mph. On the G-125-15 And I know there would'nt be to many of them motors left. But on the G-104 this rocket will still leave the pad with some blinding speed. :D
HMMMMMMM this got my attention let us know how it gose and keep us posted. Sounds cool
I would increase the sweep angle on the fins in this design to be greater than 45 degrees (its now at 43 degrees) to keep the leading edge of the fins out of the shock wave generated at the fin body tube junction. You should check these fins using the fin flutter Excel spread sheet at:


Look under Fin Flutter, the link to the spread sheet is at the end of the article.

Bruce S. Levison, NAR #69055
I'll glass my tubes from the start. I've found out. That by doing this It comes out with less wrinkles or bubbles. I tryed to come up with the best and fastest way to do this. Most of the time I can fiber glass a tube in just a few min. But this is what works best for (Me) I hope some of you will beable to use this method. Frist step is to sand the tube down with some 220 grit. This removes most of the glassine. And I think it helps the epoxy bond better with the tubes. Then I'll draw a line running the lenght of the tube.
once I have this done . I'll use a ruler to mark the glass and cut it out. This tube I'll use two wraps of 3oz. cloth. once it's done. I think it could handle a flite on a g-80-10 or the g-64-10. the glass will help when it's still doing 100' per second when the chute deploys.
The best way I've found out to hold the glass on the tube. Is with spray glue. You'll want to spray a real lite coat. here's a pic. Of the best glue I've found to do the job. With this the epoxy will bust the bond of the glue. The 3m. Glue is to good and you won't get a good epoxy bond with it.
after having sprayed a lite coat on the tube. I'll start by laying the glass out on the line and I always cut the length of the glass alittle longer than the tube. most of the time I will let it over hang by a 1/2" or more on both sides. letting the glass hang down in front of the tube. As I roll the tube I run my hand from side to side pressing the glass down. You'll see when you get a wrinkle. Just pull it up and start over. If you leave these in. When you sand the tube. You'll get groves in the glass. So this is where or what will give you a good glassing job.
When you come around to where the second layer starts. Flip the tube over. And let the glass hang down. Spray a lite coat of the glue on this part. flip it back over and finish wraping the glass.
once you have this part done I just cut the extra off. Hang it up with a coat hanger and apply the epoxy. Hope this will help .
The last few days I've been work on this rocket. And I have it where I'm about to start with the primer and painting of this projet. In order to cut back on all the pictures that I took of this build. I'll just post a few of them. And if there is any of you that want more on somthing that I did or how. Just ask and I'll try and explain it or post a picture. After the epoxy dryed. I sand the tube down with 80grit . Then I took the nose one and put a wrap of making tape on the shoulder. This holds the cone tight in the body tube. While I cut it to get the shoulder length where I wanted it. Then I cut the upper tuber to mount the cone and coupler in. This makes it look like its seamless. What got me doing this, is how many rockets have you looked at. That you can always see where the nose cone ends and the body tube starts. Just never have like it. Makes them all look like kits. And I wanted somthing diffrent. When I mount the nose cone in the body tube. I'll use some JB. Quick weld. This drys in about 10min. And it bonds real good. I'll take a razor knife and drill some small holes into the shoulder this will make little rivet. when you apply the JB. weld on the inside of the body tube. heres a few pitures of how it was done. and one with the parts ut for the project.
picture of how the cone was done useing
JB. weld. I'm going to add weight to the nose. So its just that much less I'll have to add by useing the jb. weld to put it togather.
and this is how it looks with the couple installed. In the frist piture with all the parts. You can see the holes drilled into the shoulder for the JB-weld
the motor tube used was the PML 29mm. Then I'll take a spent single use motor case and cut this for the motor stop. I know most people dont have a lathe to make ther own motor retainers. Before I got my lathe I used masking tape and duct tape to hold the motors in. When you install the motor tube leave enough room that you can take a small strip of the duct tape and wrap it real tight around the motor tube. And the shoulder of the motor case. So you would install the motor block to where it will leave the motor hanging out the tube by 1/4" Then I just use CA. glue to tack the shock cord to this. Here a picture. Like they say a picture is worth a 1000 words.
Next I'll just glue a few sticks togather. And measure where I need to put the epoxy in the body tube. So I get enough to hold the shock cord.
After having done this. I cut the fins out and slot the tube useing the dremal tool. by cutting out like I did. I get the fins to go down through the motor tube. And I'll just cut them alittle bigger for that.
When I install the fins. I just take some masking tape run it down the inside of the tube. This stops the fins from falling through. I use 6min epoxy. when it's set up enough I just cut off the waste. I'm not going to worry about the fin filets at this point. I just want a good glue joint,
This one will show what it looks like after I've cut the extra or waste from the tube. When I epoxy the fins in. You just have to wait long enough that a knife will peel it away.
rocket ready for primer and paint. Right now the weight of this rocket is 4oz. Myself I don't think thats to bad for a 29mm mount with two wraps of 3oz. fiber glass cloth. And 22" long. G-10 fins on top of that. You might say mini high power rocket:D
Very nice!

You've given me the bug! I will get the lathe turning again and make a similar retainer to yours. Should be cool!