Wildman Extreme Build Thread

[tagerton]

I am part way through the Wildman Extreme build. Everything is proceeding well.
The payload section is put together, lots of holes have been drilled, and the motor mount is now complete.
The motor mount seems a little on the short side, but I guess it's fine that a motor stick out. The kevlar is going to be very close to the fins. I suppose that's ok.

I am planning on putting a better beveled edge on the fins using a mill. I could alternatively, not. Or I could alternatively CNC a real airfoil on the fins, much like the Space Cowboy. This would involve a radial taper over the whole fin and sharp tips. Decisions.

Anyway here are some pictures.

[fyrwrxz]

Damm! Wish MY garage looked like that!

[DRAGON64]

I'm game, I'll follow along on this build. I have comnsidered many a time getting the Wildman Extreme.

[tagerton]

Damm! Wish MY garage looked like that!

It gets the job done. This is what it looked liked yesterday before I cleaned up.

[tagerton]

Updates:
Motor mount installed, rail buttons installed, lots of holes drilled. All fins are attached. No fillets yet.

I used a rubber mallet to beat the fins in. They were a very tight fit, and as some other Wildman build threads have shown, it is very important to get full contact along the root edge of the fin.

I decided not to try to put a better airfoil on the fins. I would need a nice TiCN or TiAlN or PCD coated carbide end mill and those are expensive. I didn't want to do it an imprecise way, I would rather have the rocket not spin than go 500' higher.

My Telemetrum came in the mail yesterday, and an the Adept DDC22 is on the way for backup. Anyone interested in seeing a Yagi antenna build thread / or should I just post a couple pics here?

-Ted

[tagerton]

In the past few days I have injected the internal fillets. I used Aeropoxy es6209 structural adhesive with a small amount of chopped carbon fibers. The epoxy is a little on the thick side, so I used a heat gun to heat up the body tubes to thin the epoxy. After that, the epoxy flowed evenly down the tubes.

I am going to to do the external fillets next. I am planning on using 1" dia washers to smooth it out. Here's a question: it looks like most people do NOT add chopped carbon to their external fillets. Why is that? Perhaps it doesn't smooth out as well.

The yagi antenna is progressing nicely. All rods are cut and bent. Now for soldering and testing with a network analyzer.

Sorry no pictures today.
-Ted

[Fe Dude]

Build look good.

Any time I used chopped carbon/fiberglass on external filets they tend to not smooth out so well. The fibers make a goopy stringy mess that likes to pull and glob all at once, as opposed to colloidal silica type fillers. (sorry for the technical jargon there )

[tagerton]

Build look good.

Any time I used chopped carbon/fiberglass on external filets they tend to not smooth out so well. The fibers make a goopy stringy mess that likes to pull and glob all at once, as opposed to colloidal silica type fillers. (sorry for the technical jargon there )

That's what I figured. The epoxy did seem a little stringy. I guess no one will see the internal fillets though.
I'll just be using the colloidal silica then for the external fillets.

[CarVac]

Lay peel ply over fiber-filled fillets for better shaping. You can go without it for flexy fibers like Kevlar and thinner fiberglass, but for carbon fillets it's a must.

[tagerton]

The external fillets are done. I used the carbon-paper technique to mark the lines for the fillets. I then masked everything off with masking tape and old notes.
I used a 1" dia washer to shape the fillets. According to various sources, the fillet radius should be 4-8% of the root chord length. The root chord length was 12" which corresponds roughly .5 to 1". Now at the time, I forgot my calculation was RADIUS, not diameter, so my fillets are the smallest that are aerodynamically reasonable. I probably should have gone a bit bigger, but I think it should be fine. My sense is most of the force is actually on the internal fillets, which are plenty large.

The yagi antenna is nearly done. I have posted some pictures. The graph is the output from a network analyzer. The calculations I did for the antenna were spot on. I designed for 434.55 Hz, which is the center channel of the Telemetrum. I will be adding a handle next.

-Ted

[tagerton]

Here are a couple more pictures of the yagi.

[tagerton]

So the fillets look ok. There were a lot of bubbles in them though. It will require a fair amount of sanding and filling for them to look good.

How do you guys avoid excessive amounts of bubbles in the epoxy?

[Fe Dude]

Carbon on the internals is a must, externals just need to look pretty (for me anyhow) any added strength is a nice bonus.

Can't help you on non-bubbly epoxy, but the bondo spot putty works great to fill the pinholes and such. I got mine from an ACE hardware. Its a little smelly, but dries quickly and sands easily.

Any palns for paint?

[tagerton]

Carbon on the internals is a must, externals just need to look pretty (for me anyhow) any added strength is a nice bonus.

Can't help you on non-bubbly epoxy, but the bondo spot putty works great to fill the pinholes and such. I got mine from an ACE hardware. Its a little smelly, but dries quickly and sands easily.

Any palns for paint?

Yeah I agree, the outside fillets won't do that much for strength. I've got a decent wood filler that I will be using.

I don't have definite plans for paint yet. I'm thinking about walking into some auto-body shops and seeing if I convince them to paint it. I know a lot of times they have extra paint they would throw away after painting a car that they could easily put on there. If I could pay $50 or $100 to not have to paint it my self it would be worth it. It takes a surprising amount of time and cans of paint to paint a rocket, especially one this big. I've already spent at least $40 on paint for the Mariah rocket I'm building.

For colors, I am considering blue and silver. Those are my school's colors. I'm thinking maybe if I'm 'patriotic' (that's not really the right word), the school will be more willing to support my cause. I'm going to be asking for a lot of supplies for building engines.

[tagerton]

A few updates. The fillets are done and the rocket is ready to be painted.
The Yagi antenna is complete and communicating with the Telemetrum.

I am trying to figure out the payload bay. The central issue is, metal rods parallel to the transmitting antenna will negatively affect transmission performance. That is why I am trying to design a payload bay that does not use significantly long pieces of metal.

The approach right now is to use a 3/4" thick sheet of fiberglass that I will machine down to make lighter. The force will be transmitted through the fiberglass sheet and electronics will be mounted.
There may be better ways to do this. Perhaps somehow transmitting the force through the coupler tube would be best and simply using a piece of wood or thin fiberglass. That would require securing the centering rings to the couplerer.

It sounds like, most CNC owners don't particularly like machining fiberglass, or at least the one I talked to so far.

This may or may not be the best solution. Anyone have any thoughts on payload bays?

Also, I have a 50" parachute for an old rocket (DG&A Armagedon). I believe it is a bit to small and may not be durable enough. Any owners of rockets of this size (11-15 lbs) have any favorite parachutes?

Thanks,
-Ted

[patelldp]

Any owners of rockets of this size (11-15 lbs) have any favorite parachutes?

Yes.
http://aeroconsystems.com/cart/all-p...ite-parachute/

Cheap and effective. Buy 3.

[cwbullet]

Pretty neat sled.

[tagerton]

Yes.
http://aeroconsystems.com/cart/all-p...ite-parachute/

Cheap and effective. Buy 3.

Wow that's a great deal. I will probably be getting those. When you say buy three, that's just for extras right, you're not suggesting I use three parachutes at once?

A single 60" parachute puts a 15 lb rocket at about 28 ft/s at 6000' ASL. That's a tad fast isn't it?

I believe I will also need a parachute protector or some method of protecting the chute from hot ejection gasses.

Does anyone use deployment bags?

[CarVac]

Note: those parachutes are very porous in order to survive extremely high deployment velocities (which they do with aplomb, as evidenced by that pumpkin cannon project a while back), so they have less drag than a typical 60" parachute.

[patelldp]

I have used the 66" mil-surplus chutes for at least 8 years now. My dad's 4" Public Enemy Bull Pup has used this chute in at least 10 flights and it weighs anywhere from 12-14 lbs depending on motor. I have also used the chute on my Competitor 4, and that weighs upwards of 20-23 lbs depending on motor.

I have 4 of them and love them. There are a lot of shroud lines, but they are fiberglass and do not burn. The chute fabric is more like silk than nylon, so it is nice and slick. Pack them well and you'll have a great recovery every time.

Attached is a picture of the chute after recovering my 3" Performance Rocketry Intimidator 3. Rocket weighs about 11 lbs on the pad.

[tagerton]

Perhaps the 72" chute would be best?
http://aeroconsystems.com/cart/all-p...nge-parachute/

[dixontj93060]

Perhaps the 72" chute would be best?
http://aeroconsystems.com/cart/all-p...nge-parachute/

I had one of these before. Unlike the ones suggested by Dan, these are very hefty and need a lot of room to pack. The inflated look is very cool, but you need a ton of room to pack them.

[tagerton]

Ok so it sounds like I don't want that 72" parachute.
Is 28 ft/s too fast for an all fiberglass rocket like this?

Has anyone used L brackets to attach the CR's to the payload bay tube. In other words, the sled would not carry any weight, but the CR's could be bolted to the tube with an L bracket.

[CarVac]

Really you should keep to twenty or less. Otherwise you could, say, heavily dent a car on landing.

[blackjack2564]

"Any owners of rockets of this size (11-15 lbs) have any favorite parachutes?"




Wildman recommends the Recon Recovery 60in. or a Topflight 84in. for this rocket.

[tagerton]

Ok, I will be ordering a parachute soon. I've never launched a dual deploy rocket of this diameter. What is the best/recommended way to protect the parachute and nylon shock cords from the ejection charge gasses? I see nomex protectors for sale and was planning on getting one of those unless anyone has better ideas.

Also, another update: the rocket is off to a car body shop. Shout out to Autosport in Golden, co for just charging me for materials. (although they understandably didn't agree to the flame paint job).

-Ted