Building a Bigger Big Daddy Akavish

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Roger Smith
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We can rebuild him. We have the technology. We can make him better than he was. Better...stronger...faster.

Last November, our launch of the Big Daddy Akavish went astray when a hole opened up in the side of the Aerotech motor. Hopping back on the horse, we launched the Akavish in March on a CTI motor and ... the motor came apart resulting in a rather hard landing for the furry rocket.



Since a spider-themed rocket should have eight legs, not three, we decided a rebuild was in order.

We decided to make the new Big Daddy Akavish a little bigger.

I'll post major progress updates here, but you can follow our progress in greater detail in the Bigger Big Daddy Akavish Build at RocketReviews.com.

-- Roger
 
Getting Started

The fuselage of the Akavish is made from 11.4" diameter tubing from Public Missiles Ltd. I cut a section about 16" long using my table saw. I cut two centering rings and started to glue one of the rings into the tube before I realized that I shouldn't do that yet!




Fortunately, I realized my mistake before the glue dried.

-- Roger
 
Internal Structure

Next, I cut out pieces from the MDF and from a 1" square dowel to use to create the structure inside the Akavish. These parts form channels where the legs slide in.

I cut a 1 1/2" square dowel to create eight cubes. Into each cube, I drilled a hole then used a tap to create a thread in the hole. I used a die to add corresponding threads to eight long mop handles.



The cubes are attached to the top of a channel allowing a leg to be screwed into place.




Cool, huh?

-- Roger
 
Assembling the Inside

I assembled the internal pieces, adding covers to the channels for the legs and gluing everything to the lower centering ring and motor tube.




I added some strips of fiberglass over all the edges to reinforce the bonds.

-- Roger
 
This is going to be pretty unique.

I think we are all waiting a bit to see what the heck is going on before we comment, lol.
 
I think we are all waiting a bit to see what the heck is going on before we comment, lol.

Hmmm ... I guess that it's not looking much like a rocket (or even a spider) so far. :)

Just wait .....

-- Roger
 
Altimeter Mounting

Obviously, this rocket is not going to have a standard electronics bay, so I had to devise a different way to mount the altimeter.

I used the table saw to rip two strips of wood. The saw was also used to cut thin slots in each of them. A piece of G10 slides into the slots.

I mounted the altimeter and a battery holder on the piece of fiberglass.




I attached the altimeter sled to a bulkhead. On the other side, I added a terminal strip where the e-match for the ejection charge will be hooked up.

-- Roger
 
Assembling the Fuselage

I cut holes in the bottom of the bodytube for the legs. I used a reciprocating saw to cut out the slots. It worked okay, but left rough edges. I installed a toggle switch between two of the holes. It'll connect to the altimeter. Then, I glued the insides into the body tube.




Then I added the top centering ring. The altimeter slides into a hole in the ring and is secured with a couple of wing screws.



Uh oh! I just noticed that the triangles are pointing the wrong way! They must have printed them upside-down in the tube.

-- Roger
 
Cool stuff Roger!

Thanks!

It's a little silly, but the way the altimeter mounts appeals to me. I think it's cool.

I came home from work one night after having assembled the altimeter holder the previous night. I was excited to finally see it work. I changed out of my work clothes then went into the garage. I tried sliding the altimeter into the hole and ... it didn't fit. I had measured something wrong. Ugh!

I had to cut the bulkhead off and make a new one with the altimeter sled mounted a little off-center. That's why the screws are a little askew. But, it still works well. And, it's pretty cool. :)

-- Roger
 
Tomorrow's post is going to be really cool! :)

-- Roger
 
I had to cut the bulkhead off and make a new one with the altimeter sled mounted a little off-center. That's why the screws are a little askew. But, it still works well. And, it's pretty cool. :)

-- Roger
I say odd-roc's shouldn't be perfect :)
 
Aha! Now It's Starting to Look Like ... Something

I realized a while ago that the way I have the legs attached isn't going to work by itself. The legs are going to take some punishment on the way up and, especially, when the rocket lands. So, I tried out some ideas for reinforcing the attachment. Most of the ideas were too complicated. Then, while getting something out of our trailer, I noticed the rubber "tarp straps" that I use like bungee cords to hold things in place. Aha!




The rubber straps help hold the legs in place while offering a little springiness. I had to order more wing screws. I only had a couple left. You can also see how the "rail button mount" slides into the body and is attached with a bolt. Being able to take the rocket apart will make it much easier to transport.

Okay ... I guess that it is finally time to test fit the body and legs and see what it looks like ....




Oh my, it's a little bigger than I thought it would be. :)

-- Roger
 
Okay ... this thread has now caught up with my progress in the Bigger Big Daddy Akavish build.

The other day I ran out of fiberglassing epoxy, so I ordered more from US Composites. They are located not far away, so I received the epoxy yesterday, just a couple of days after ordering it. I also ordered some threaded inserts for attaching the rail buttons and some wing screws from McMaster Carr. The inserts arrived just after I clicked the button to submit my online order. The wing screws were shipped from Chicago and should arrive today.

Things Left To Do:


  1. Attach rail buttons to the rail button stick holder thingy. I'm also going to add a rail button or two to the body tube. Lining them up and making sure they extend out the same distance is going to be a challenge.
  2. Assemble the motor mount. For the previous Big Daddy Akavish, I just slid the motor in and held it in place with tape around the motor and motor tube. I've planned something much more elegant for this rocket.
  3. Add the head. What's a spider without a head? Like the previous incarnation of the BDA, the head will be made of foam covered with fiberglass.
  4. Add the feet. I ordered foam balls for the feet more than a month ago and the vendor hasn't shipped them yet. Ugh.
  5. Add the recovery system. We have plans for a cool parachute. The motor mount will use an eyebolt at the top. The shock cord will connect to the eye bolt.
  6. Make it furry. For our small Akavishes, Bracha cut hundreds of one-inch long pieces of yarn. She glued one end of each piece onto the rocket. Once all of the yarn was in place and the glue dry, she combed out the yarn to create the fur. We're not doing it that way on this rocket.

This rocket, as with most of my rockets, is turning out to be larger and heavier than I had intended when I started. I was hoping to produce something that would fly on K and L motors, but I think it may be a bit too heavy for a K. It's about 30 pounds now. With the motor, fur, and parachute, it'll be over 40 pounds.

-- Roger
 
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Looking good!!

You and Bracha should line'em all up for a family portrait!
 
Rail Buttons

Today, I added rail button attachments. First I marked the center line on the rail button holder. Then, using the drill press, I drilled small holes on the line. The small holes helped ensure that the larger holes I later drilled were right on the center line. I screwed threaded inserts into holes using a hex wrench.



The rail buttons screw into the threaded inserts and are removable.



I included a rail button attachment on the top of the board so that, when it is installed in the rocket, I can add a rail button on the side of the body tube. I'll have to use a longer screw and add some washers to make the rail button align with the others.

-- Roger
 
Motor Mount

A unique problem for the Akavish is how to handle motors of different lengths. The previous Big Daddy Akavish solved the problem in a simple way. I just let the motor hang out the back of the rocket and I wrapped tape around it to keep it in place. For the new Akavish, I'm doing something a little more elegant.

First, I added a thick centering ring around the 98mm motor tube on the bottom of the body of the rocket. On the other end of the motor tube, I added a thick bulkhead that has a 3/8" screw eye through it.

For a 98mm motor, I will cut a length of 98mm tubing. The tube will slide over the motor. The motor will be inserted into the motor mount and the tube will slide into the centering ring on the bottom of the rocket. I'll just screw the motor into the bolt on the end of the screw eye and it'll hold the tube in place.

For a smaller motor, such as the 75mm motor I plan to use, I'll construct an adapter. I made one for the CTI 75mm 3-Grain case I have.



The adapter consists of a 75mm motor tube and centering rings inside a 98mm tube. At the top of the 98mm tube is a coupler.



The adapter slides into the motor tube. The motor will be inserted in the adapter then screwed into the bolt at the top of the motor tube.

-- Roger
 
The Head

The head of the Akavish is a large foam ball. It comes in two hollow halves. To fit over the body, we had to cut a 12" hole through the ball.

A sat each half ball on the floor then placed a section of the 12" tubing on the top of the half ball.




I used a level to make sure the tube was centered then used a pen to draw a circle where the tube met the ball.




Bracha used a drywall saw to cut the ball halves on the lines.




The two halves of the ball were glued together and then glued onto the body tube.

-- Roger
 
The head looks a little small for the length of the legs. That doesn't surprise me because I had originally planned to cut about 12" off of each of the handles used as legs. But, I decided to hold off on cutting them to see what it looked like. It'll be easier later to shorten the legs than it would be to make them longer. So, I'll wait until we put it all together again to decide.

-- Roger
 
Nose Cone

For the nose cone, we used one of the pieces cut out of the foam ball. I started with a couple of center rings that I had in my big box o' rings. I added a lip around the larger ring by cutting a thin piece of the body tube and gluing it in place. I added a screw eye (actually an eye nut) into a smaller centering ring which I clued on the back of the larger ring.




On top of the rings, I glued the foam piece.




In place, it looks pretty good.



-- Roger
 
That was the second nose cone that I made. The "lip" on the first one was too thick so it didn't look right. I started over and made the one pictured above.

-- Roger
 
I know that you've been waiting on the edge of your seat for an update so ....

Over the weekend, we covered the foam parts with a layer of fiberglass. We cut strips of fiberglass cloth, wetted them in the epoxy, and applied them to the foam "paper mache" style. We used lightweight fabric, but it's overlapped into multiple layers. We left the parts to dry. Later, we'll check to see if there are any areas that need more 'glass.

Sorry. No photos. It was pretty messy. Not something you'd want to see. Sort of like the making of sausage. Everything is going to be covered by a coat of fur, so we didn't worry too much about being neat.

-- Roger
 
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