54mm min dia Build Thread

[tfish]

I'm building a new 54mm min dia rocket. My old one has a few flights on it and is getting pretty beat up. My old Rocket was 'mostly' your typical glass over cardboard sort of thing. It was to short for the new longer 54mm motors on the market. So the new Rocket will be about 9" longer and should be about 52" long and be able to take a 30" long motor. I willl be using carbon fiber and some G-10 on this new rocket.

I figured it might help some one if I started a build thread on it.

I was able to lay up one of the body tubes yesterday. I used a long 54mm motor as the mandrel. Over that I placed 2 layers of 2 mil mylar as a release. I then used 3 layers of 5.7 oz carbon fiber, high temp epoxy, then over that I placed 2 layers of peel ply. Working all the excess epoxy out as I went. The finished tube is strong and is fairly light. The tube is 24.5" long and weighs 147 grams. I hope to lay up one more tube today and hope to get to laying up the nose cone in the next few days.

Tony

 

[Reed Goodwin]

That looks very neat, clean and professional. Good job! I look forward to seeing the rest of the build thread.
Reed

 

[dragonshiprider]

Thanks for starting this thread.It may come in handy down the road with my own CF VB Extreme 54 build.

 

[tfish]

Here is a photo of the second tube all rolled up. The green masking tape keeps the epoxy off the motor case and holds the mylar in place. The black line is to let me know where the carbon fiber started. I start with a piece longer then needed..in this case 21" wide and then cut off the extra at the line once I get three wraps on. Yu can see the carbon fiber under the peel ply.
Tony

 

[tfish]

Here are both tubes next to a K700 case. The second tube weighed 150 grams.
Tony

 

[tfish]

A close up of the tubes.when you apply the peel ply work out the extra epoxy with a gloved hand working from the center out to the ends as your wrap the peel ply on. The extra epoxy oozes out the pores of the peel ply. When you remove the peel ply there is a very minute texture to the tubes. That's is why they don't have a glassy smooth finsih. I wished I would have weighed the the carbon fiber before I started to know how much epoxy it took. I started with 125 grams of epoxy and had some left over plus what ooozed out.
Tony

 

[tfish]

Here is the mold for the nose cone. The design is sort of like a Von Karmen. It's design came from research done on a group project. A wooden plug was turned and a mold taken from the plug. John Cokers method was used for the mold.
https://www.jcrocket.com/nike-asp.shtml
I plan on doing it a bit different then how John does it. Carbon fiber is hard to get it to hold the shap of the mold. So I'm going to use one layer (maybe two) of carbon fiber and let it get rubbery. Then trim it down to the edges of the mold. The remaining (2?) layers will be fiberglass (which I find easier to work with) will be added and the mold halves put together while it's still wet. So that there is not a 'major' cold joint holding the halves together. The shock cord attachment will be placed in the tip of the nose cone (the green loop looking thing in the photo) The silver part in the mold..on the shoulder area..is some of that silver tape stuff. These body tubes came out a tiny bit smaller ID then the test pieces. Hopefully the tape will make the shoulder just right.
Tony

 

[Felix]

Nice Job T fish!
What I use for laminating Body Tubes is shrinkink tube(the RC Stuff for wrapping battery packs) instead of peel ply. Laminate your body tube as usual, then pull the shrinking tube over it (the shrinking tube shouldn´t be too big, just that big that you can easily pull it over the body tube without touching the cloth) and then shrink it from the middle to the outside. This way, the shinking tube will squeeze out all excess epoxy, the cloth will be saturate better as the hotter epoxy has a lower viscosity and air bubbles will be squeezed out, just like with vacuum bagging.
When the epoxy is cured(don´t wait too long, as it will be harder to remove the shrinking tube then), carefully heat up the shrinking tube with a hairdrayer and make a small cut on one end with an exacto knife. This way, the shinking tube can be peeled of and you get a smooth, shiny finish without the expenses of vacuum bagging.
Maybe this is interesting for you.

Felix Nimtz

 

[Rockdale]

Hi Tony,

How did you cut the tubes so nicely and squarely?

John R

 

[tfish]

Felix, I tried the shrink tape and did not like it..or did not know how to use it right. I did see soom of the stuff you're talking about. Looks interesting. I kinda like peel ply..the minute dimples are not a problem for me..

John R..long time no see..I use a 'metal chop saw' ..makes nice clean even cuts.

I just pulled the nose from the mold and will post photos tomorrow.

Tony

 

[tfish]

Here is a photo of the mold layed and and the mold halves put together.

 

[tfish]

Here is the nose cone with the flashing removed. The shoulder was a little big but I was able to turn it down to fit.
Tony

 

[rocketkyle]

that looks really good, Tfish! I'm impressed. Hope you weren't planning on using transmitters, otherwise great!

 

[tfish]

Kyle, I am. Just won't have a signal until apogee. And if I don't get a signal (came in hot) it will just save me time not having to go look for it.
Tony

 

[rocketkyle]

o ok, that makes sense. Good luck with the rest of the build!

 

[tfish]

Here are the fins. I started with .065 G-10. The G-10 was sanded with 60 grit and then 'scratched up' with an old saz-al blade. To give the epoxy a place to bite. Then a layer of 5.7 carbon fiber was vacuum bagged to each side. The fins are now .088 thick. Once the fins were cut I used some 220 wet sand paper on a flat surface to give them their 'rough' leading and trailing edges. A .063 drill bit was used to drill a bunch of holes in the root edge to give the epoxy a place to bite. The top fin before beveling. the middle fin after beveling. The bottom fin beveled and 'roughed up' to give the epoxy a place to bite.
Tony

 

[rocketkyle]

Your bevels look really good. i need to get me some carbon fibre!

 

[cherokeej]

Looking good, Tony! I like the way the n/c came out.

James

 

[tfish]

James, yes it came out nice. I like John's mold method better then the way I had been doing it. The nose cone design is from the 100K group project. It's suppose to be the best design/shape for upper mach flights. Once they got the program done it was easy to change it's size, 98mm- 29mm. The hardest part is turning the wooden plug. It's time consuming to get it just right. John's mold making method is really slick.
Tony

 

[tfish]

Here's a photo of the fins 'tacked' on. I used 60 grit to rough up the rody tube and then used a sawz-al blade to roughen it up even more. The fins are done the same way. It just not show up in the photo.
Tony

 

[cherokeej]

Looking good, Tony! I see I've got my work cut out for me if I want my name on that 54mm L record.

Currently rebuilding my Competitor 4. Planning a 3 way drag race with Steve K and Dave R at AeroHot. Just for fun. Lunar-nuts all flying Perforomance kits.

Take care, Tony, and I'll se you at Mudrock...

James

 

[tfish]

Started the fin attachement today. Taped off the area to prevent getting epoxy all over everything. I then wetted out everything. I make fin fillet out of cut up carbon fiber and epoxy..I call it goop. And lay it in place with a stir stick. A thin coat of epoxy over this and then the first layer of carbon. The first layer only goes about 1/2 to 2/3 of the way up the fins. The last layer does go from fin to fin. Work out any extra epoxy. I use my finger to do the final 'forming' to the fin fillet. Once the epoxy gets to the rubber stage I will trim it.

 

[tfish]

for the fillets I use cut up carbon fiber. You want to cut it as small as you can. When it's cut to long it's harder to work with..Like working with a cat's hair ball..(not that I've worked with cat hair balls or anything) You could use fiberglass too. Straight epoxy will crack and keep cracking. Epoxy and other filters arn't as strong..(in my opinion)..the carbon or glass adds strength to the epoxy..if you add to much epoxy to it..it's runny and won't stay in place..to little and it's hard to work with.

 

[tfish]

You have to look close but you can see the fillet in place. It does not need to be perfect. It gets it's final shape at the very end.

 

[tfish]

Here is the first piece of carbon fiber. Before being wetted out. (I had to crop the photo a bunch)..but this piece runs fron 1/2 way up one fin across the BT 1/2 way up the other fin.

 

[tfish]

More photo problems....anyway..here is second and last layer of carbon..before being wetted out.a photo of the front half.

 

[tfish]

and the back half..

 

[flyr98]

Excellent job Tony!

 

[Nate]

that looks fantastic so far. I'm very impressed with your work on the carbon fiber.

that nosecone was absolutley amazing looking.

 

[tfish]

Here is the electronics bay/coupler made from a spent K250. The bottom has a bulkhead glued in place. The electronics board (from my old 54mm min dia rocket) slides between the 2 threaded rods. The 'lid' is bolted on as the the shock cord attachement (which is the same on the bottom) This will be glues into the rocket to keep the exterior 'screw free'.
Tony