Madcow 4" fiberglass Super DX3 build thread

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got started on the fins, I put on tape as a depth gauge and cut slits on the fin tabs for a strong bound and sanded the sides of the fin tabs as well, I also got the first fin tacked on using 5 min epoxy, I'll reinforce the joint using aeropoxy and fiberglass tape once I get all 3 fins tacked on.
 
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This is fiberglass tape, the same stuff used for joining drywall together, I read someware some one using this on their rocket built, whats good about this is its sticky on one side and you can just put it on with no glue or epoxy.
I also put on the first set of internal fillets, I used talc(baby powder) to thicken the aeropoxy to peanutbutter like consistency.
 
I now got all internal fillets done and the aft centering ring glued on, so far it looks like that the rocket will be ready for Red Glare in April.:headbang::w::
 
Just for fun I put the rocket together with the motor case, retainer, 2 parachutes, shock cords and quick links and put it on the scale, so far it weighs 9lbs, and I still need to put on fillets and paint it.
In other rocketry news, I will soon be getting a 4x upscale of the Estes Ram Jet from K and S rockets, this is my number one favorite kit and I'm very excited about getting this kit
 
I'm pretty much done the build for now, all I have left to do is the external fillets, I'll start on them over the week end, I don't want to feel rushed when I'm doing them, once those are done I'll start the ground testing the following week end, I want to do the ground testing before I paint so I don't mess up the paint and decals.
 
Kehoes23 said:
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This is fiberglass tape, the same stuff used for joining drywall together, I read someware some one using this on their rocket built, whats good about this is its sticky on one side and you can just put it on with no glue or epoxy.
I also put on the first set of internal fillets, I used talc(baby powder) to thicken the aeropoxy to peanutbutter like consistency.
Click to expand...

There is an RC outfit called Rite Wing that uses the yellow version of this wall seam tape to build ultra-strong flying wings... first I have seen it used for a rocketry application; good job. The build looks great, looking forward to a range report.
 
DRAGON64 said:
There is an RC outfit called Rite Wing that uses the yellow version of this wall seam tape to build ultra-strong flying wings... first I have seen it used for a rocketry application; good job. The build looks great, looking forward to a range report.
Click to expand...
thanks dragon64, my thinking was that the epoxy would have a better hold with this fiberglass tape then with the fiberglass cloth, but not sure if it is stronger then the cloth, I also used it for its sticky on one side and that it would be easy to put on in such a tight space, I've also used it on the forward centering ring as well and I'm also thinking about using the fiberglass tape for the exturnal fillets as well.
 
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Meanwhile at home, this came in the mail for me from K&S Rocketry its the Estes Ram Jet 4X up scale I cant wait to start on this but first I must finish the Super DX3
 
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the tools I used for the fillets, forgot to add the tape and paper towels
 
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I used a sharpie to color the pvc tube and rubed it on the fins and airframe to get straight lines then sanded with 60 grit
 
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after the sanding I clean the area with rubing alcohol then put on tape and the fillets.
now that the build is done besides paint and decals I will do the ground testing then paint.
 
With much consideration and my better understanding the math part to find the volume of space for the e bay, I'm going to fill in two of the three 1/4" port holes in the e bay.

Here is my mistake: I have a 4"x8" e bay
So, what I did was this: 3.14x4x4x8 and I got a volume of over 400, only if the e bay was 8"x8"
Now it was better explained to me, what I should have done was this: 3.14x4x8 or 3.14x2x2x8 which would give me a volume of 100 and to stick with the rule of thumb: 1/4" per 100
 
I would go with 3 holes before having 4, you don't want a possible chance of wind blowing through your ebay and setting off charges. Adept says always use a odd number of holes.
gp
 
I hate making a small batch of epoxy I can not get the mix ratio right, I filled in two of the three holes with a small batch of epoxy and it did not harden, it stayed sticky and gell like state, I should have stuck with JB weld to fill in the holes.
The third hole I'm not going to fill in for I need this hole big enough to fit a screwdriver to turn on the altimiters, I just might drill out the other two but not as big, I was thinking 1/8" holes.
 
here are the links to my ground test, the first one failed, I used 3 4-40 pins and 1.2 grams of BP, on the second test I got rid of the 3 4-40 shear pins and moved the vent hole closer to the nose cone and I used tape in place on the shear pins to hold the nose cone, since I was using 4-40 shear pins for both main chute and drouge chute I also got rid of the 3 4-40 shear pins for the drouge and used 2 2-56 shear pins and 1.5 grams of black powder
 
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it looks like that I only got one video up, if you go to my you tube channel you can see the other two videos, my you tube channel is shaggy doo
 
Kehoes23 said:
the first one failed, I used 3 4-40 pins and 1.2 grams of BP, on the second test I got rid of the 3 4-40 shear pins and moved the vent hole closer to the nose cone and I used tape in place on the shear pins to hold the nose cone
Click to expand...

Just curious - - why did you give up on the shear pins instead of increasing the BP?
 
csoechtig said:
Just curious - - why did you give up on the shear pins instead of increasing the BP?
Click to expand...

My thinking was Since the shoulder on the nose cone is 4.5" and a little bit of tape it would be good, but when you brought up the shear pins, I started to think about it and I forgot that I may need to add weight in the nose cone and the tape may not be a good idea and I would have to use shear pins, but this time I'm going to use two 2-56 pins instead of three 4-40, I got cought up in the ejection charge excitement and forgot about the nose weight.
 
Seems someone thought 4-40 shear pins would be excessive and recommended 2-56 previously.:wink:
Looking good. What are your plans for paint?
-Ken
 
new2hpr said:
Seems someone thought 4-40 shear pins would be excessive and recommended 2-56 previously.:wink:
Looking good. What are your plans for paint?
-Ken
Click to expand...
Thanks Ken, the paint will be white on the body and orange on the fins and nose cone, I got decals made from Mark at sticker shock, but I'm not going to disclose them just yet, when I'm done with paint and decals I'll post photos
 
So the build is done the week end is here and the weather is going to be nice so I can now start painting the rocket. :horse::headbang:
 
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the first coat of primer, I realy like fiberglass kits, there are no spirals to fill but I do have some pits and holes to fill.
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the first fillet cover, I used Elmers wood filler, the one on the left was after the sanding, the one on the right is the second coat of wood filler.
 
So, when I was at the auto store the other day picking up spray paint I had a interesting talk with the sales clerk, this is how it went.
Me: finally the weather is nice enough to start painting again
Sales clerk: oh yeah, what are you painting?
Me: high power rockets.
Sales clerk: ???
When I said high power rockets, he looked at me like I had three heads, I guess that was not the answer he was looking for.
Has something like this happen to anyone else? This is the first time it's happen to me and thought I would share my story with TRF.
 
Kehoes23 said:
When I said high power rockets, he looked at me like I had three heads, I guess that was not the answer he was looking for.
Has something like this happen to anyone else? This is the first time it's happen to me and thought I would share my story with TRF.
Click to expand...
Same thing happened to me while I was at an electronics store looking for AV Bay parts.
 

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