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-   -   Nike Hercules construction (http://www.oldrocketforum.com/showthread.php?t=11603)

jetlag 09-14-2012 07:33 PM

Nike Hercules construction
 
5 Attachment(s)
Well, I decided to take a break from the usual rocket-making and tackle the new Nike Hercules kit by The Launch Pad. I've had the kit for a few months now, and since I have built a Krypton and a Standard Missile by the same folks, I wanted to see how this, arguably one of the most magnificent missiles ever created, would be rendered. It is designed for 29mm engine power.
I did not see a review in EMRR, so I may write one there, also.

Here we go!

The kit comes in a medium-sized box with the Nike Hercules (NH) picture on the front (pic. 1).

The main body tube is made up of 2 x 21.5 inch long BT-60 tubes joined in the middle. Notice I've already epoxied these together with the supplied coupler (pic. 2).

The booster consists of 4 x 13-5/8 long BT-60 tubes. Lots and lots of cardstock shrouds, black carbon centering rings and a former, balsa strips of several sizes, two balsa sheets-3/16 and 1/8 thick, recovery hardware for 2 included mylar oblong parachutes, weights and a big screw eye, and a pointy nose cone.

I have already made the engine mount, which is a simple heavy-walled 4.5 inch long tube for a 29mm engine.

The pictures are taken in my shop, which appears a bit messy, but I assure you, I know where everything is. I build on 9.5 foot solid doors; I need the lengths because I build airplanes, too, out of boxes of lumber, and I have to have FLAT surfaces, as you know!

Hope this is fun!

Allen

Leo 09-14-2012 07:40 PM

Subscibed :D

jetlag 09-14-2012 07:49 PM

3 Attachment(s)
As I said, the 2 x 21.5 inch BT-60 tubes were joined using 30 minute epoxy, and the assembly was rolled back and forth to check for straightness.

Next I had to cut out the heavy paper guide to use on the 4 booster tubes. Here, one has to slice a longitudinal section out of each tube. I made the marks and used an aluminum angle to draw the lines straight. I cut the sections out with scissors, as suggested in the instructions, where they have a 'C' shape.

BTW, the instructions are quite well-written and explanatory. The booklet is 20 pages with 79 steps. I'm gonna try to do this stepwise and hope I don't screw anything up!

Next, I marked the bottom of the tube in a cruciform (4) pattern; these lines go about 13" up the BT and are used as the guides for the 12.5" 1/8 x 1/8 balsa strips that get glued down.
These in turn become the guides for the four booster tubes.
I glued the strips using thin CA; I attached each one a little at a time to ensure they stayed straight. I kept the drawn line to the left each strip for the visual clue.

jetlag 09-14-2012 08:01 PM

You, no doubt, noticed that funny-looking round shiney washer thingy in the first picture above.

This is a carbon centering ring that has 2 heavy (11g each) washers epoxied onto it. I inserted this 10 inches down the main BT from the front and used epoxy to secure it. This little assembled ring has two purposes: It forms the floor of the parachute compartment and adds some of the weight needed to help balance the model. It is not a baffle, so wadding will be have to be used.

That's all for tonight. I'm getting more excited as I go, but reading forward in the instructions shows some rather intricate steps to come.
If I had not been up since 0300, I might go on and glue up the boosters, but we can do that tomorrow.

One more thing about these instructions. There is text (steps) on the left side of the page, while CAD drawings and illustrations are on the right side for clarity. So far, they are fantastic!
I'll get a shot of a page tomorrow, so you can see how nice it is.

Allen

snaquin 09-14-2012 08:42 PM

Allen,

Looks like a very interesting build!

I see now why it's a skill level 5 kit ..... plenty of parts and quite a stack of shrouds to assemble.

(Nice Bomarc in the background of the second image)

:)

.

jetlag 09-14-2012 09:05 PM

Thanks, Steve!
That's my '95ish NCR Bomarc. I fly it all the time! The key to its longevity has been the epoxied triangle stock I used to shore up the Ramjets from the inside of the BT. That, and using AT G80 (or G77, 78 -4) SU engines and 2 x 36 inch parachutes. It would most likely take a small H, but I have never certified for some reason. :rolleyes:

It's a heavy beast!

A-

jetlag 09-17-2012 03:47 PM

the four boosters
 
4 Attachment(s)
Over the weekend, I was able to accomplish a bit more.

I lined up or prefit the tubes I cut to get a good idea of the look and process.

I used Titebond II down the inside edges of the 1/8 x 1/8 strakes and laid 1 tube down, then the one opposite. I used the scotchguard blue tape and rubber bands to make them lay up the right way, then let them dry.
Then the next two tubes were laid down similarly to the first two, and all was banded together.

Pretty straightforward and boring, but they look good.

jetlag 09-17-2012 03:56 PM

Engine mount
 
The mount was assembled earlier with 30 min. epoxy. I needed to run the Dremel on the outside of the centering rings a tiny bit to get the whole assembly to slide into the BT.

Before I glued it in, however, I coated what would be the 3 inches (or so) in front of the mount with thinned 30 min epoxy to protect that area from the vigorous ejection charges I anticipate. I used unthinned 30 min epoxy to glue the mount in, the aft centering ring 3/4 deep from the end. This recesses the mount about 1/2 inch.

I did not use kevlar on the mount; it would be toast after a few launches, as it would be just too close the ejection charge. I really have not decided yet how I will attach it. Plenty of time for that!

jetlag 09-17-2012 04:10 PM

4 into 1... wait, What?
 
4 Attachment(s)
This was a step I was not looking forward to: the dreaded 4 into 1 transition, all made from cardstock.
It is an intricately drawn pattern. Nice to know I can still wield a pair of scissors with the best of 'em!
Also, there are 4 'reinforcement' triangles to be cut. The lines on the patterns show where one must 'score' using a ballpoint pen. I also bent the paper at the lines using a narrow piece of metal, so they would be really straight. I glued in the little triangles; these are part of the flat, straight areas of the transition.
After it was all bent and glued, I was pleasantly surprised at how good it looked.

I placed a 3-inch diam. centering ring in front, and glued in place with the Titebond II; unfortunately for me, I forgot this would soften the cardstock after a while. :mad:

While I was working on the aft end with the funky-shaped, 4-lobed ring, I kinda squished the transition where it had softened. Later here...

jetlag 09-17-2012 04:26 PM

4 lobes
 
4 Attachment(s)
After some playing around with it, I was able to make that 4-lobed just barely fit into aft end of the transition. I turned to find my CA and it popped out. Ok.
Again, got it in place, holding with my fingers, where's the CA, just barely....pop!
Grrr!
Took several tries, but I got it, finally.
I used one-inch pieces of balsa to press 2 sides flat and centered, then hit with CA.
Did the same for the other 2 opposing flat sides. After they were dry, I went around the whole ring with the CA.
Wow, it really looked good, I thought. Then I caught something that looked a bit strange; the front had partially collapsed into the Titebond I had used earlier. Not terribly, but it was noticeable and it had to be absolutely straight.
I pulled on the 2 centering rings to pull out the kink and hit it with CA. It worked! I went all the way around and pulled it out straight again.
The entire transition got a coating of thin CA to strengthen, both inside and out, something the instructions directed me to do anyway.
It finished so nicely, I tried it out on the main BT.


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