Level 3 Build - Wildman "Extreme Wildthang"

[Golfpro62]

Here is the build thread I promised. It is my TRA Level 3 certification build. After 13 or so years of flying mid & high power I am finally pulling the trigger. I chose the Wildman "Extreme Wildthang" I love the classic swept wing design with a "W" cut into each fin. I have never gone over 10,000 feet or broke mach 1. This rocket will do both easily even on a baby "M". Because of those facts my plan is to make the attempt at Airfest in the Argonia rocket pasture. Even if the wind is blowing 20 mph it would still be a go down there.

Here are the specs:

4 inch diameter
101 inches tall
Weight: approx 15 pounds (no engine), approx 25 pounds (with a CTI M2250 C-Star, or AT M1297 White Lightning)
Avionics: two RRC2 Minis
Recovery: 84" Rocketman standard chute, 24" Rocketman Mach 2 drogue
Tracking: Comm Spec AT-2B transmitter, PR 100 Receiver

I love rockets and one of the benefits is the people you meet along the way, a pretty diverse group who all have the same passion for Rocketry. Over the years I have been lucky to meet some great people who were willing to share their time and knowledge with me, people from all over the nation. Rocket people are always eager to answer any questions and give you a hand. You all know who you are and I wanted to say thank you for all the help along the way and I try to pass it forward.

I will try to move right along with this. Since I am documenting all this for my TAP Members it should be easy for me to cut and paste my way through this. I have lots of pics already so let the thread begin.

 

[Golfpro62]

I pretty much built this kit per the instructions that either Crazy Jim or Tim wrote for these kits. It's hard to argue with the success of these guys and I believe if you follow their lead, these kits are nearly indestructible.

I used West Systems Epoxy through out the build except for tacking purposes where I used either JB Quick or equivalent fast set epoxy. Chopped carbon fiber was used to strengthen the injected internal fillets, and coloidal silica was used for thickening purposes on the external fillets. I will also used JB Weld to attach the Aeropac 75MM Motor Retainer. I forgot to mention in my first post this rocket has a 75mm motor mount in it.

Here are a few pics: one of what was in the box (plus the Aeropac Retainer) Tim must have been running low on tubes - the tubes were natural green and the couplers were yellow, I also included a pic of the Fins, and a sneak peak from test fitting the fins.

 

[Golfpro62]

This kit came with one of the new filament wound nosecones with a metal tip. Since I have recently added a comm spec tracker to the rocketry tackle box I wanted to utilize the nosecone for this task. First up was to permanently attach the metal tip with epoxy. I had ordered an extra airframe & coupler bulkhead, my idea was to create a small electronics bay within the nosecone - just like your standard alt bay assembly. I epoxied them to one end of the nosecone coupler, and drilled a couple holes in them for some threaded rods. I cut a couple 1/4" threaded rods and permantly epoxied them to the bulkhead. Next, I had a full sheet of G10 that I ordered to make a couple alt bay sleds so I cut a 3" by 4" piece and glued a couple igniter wire tubes to the sled and now I have a simple sled to hold my tracker. The antenna will go through the bulkhead hole where you would ordinarily put a eyebolt. Once I had the coupler assembly finished I roughed up the coupler and the inside of the nosecone and slopped some epoxy on the nosecone wall and twisted it in place permanently. I am considering whether or not this is strong enough considering the weight that will be dangling below it. I am thinking about adding 3 small screws to ensure it holds under the pressure - any thoughts?

 

[Eat, sleep, and Fly]

This kit came with one of the new filament wound nosecones with a metal tip. Since I have recently added a comm spec tracker to the rocketry tackle box I wanted to utilize the nosecone for this task. First up was to permanently attach the metal tip with epoxy. I had ordered an extra airframe & coupler bulkhead, my idea was to create a small electronics bay within the nosecone - just like your standard alt bay assembly. I epoxied them to one end of the nosecone coupler, and drilled a couple holes in them for some threaded rods. I cut a couple 1/4" threaded rods and permantly epoxied them to the bulkhead. Next, I had a full sheet of G10 that I ordered to make a couple alt bay sleds so I cut a 3" by 4" piece and glued a couple igniter wire tubes to the sled and now I have a simple sled to hold my tracker. The antenna will go through the bulkhead hole where you would ordinarily put a eyebolt. Once I had the coupler assembly finished I roughed up the coupler and the inside of the nosecone and slopped some epoxy on the nosecone wall and twisted it in place permanently. I am considering whether or not this is strong enough considering the weight that will be dangling below it. I am thinking about adding 3 small screws to ensure it holds under the pressure - any thoughts?

View attachment 127336View attachment 127337View attachment 127338View attachment 127339View attachment 127340

Where did you put the epoxy on the NC tip? If you put it on the internal bulkhead, then you should be able to unscrew the tip, and tap out the bolt. From there, you can screw a 1/4-20 allthread into the tip, and run it to the forward bulkhead of the coupler. Bolt in together, and you are done. If you unscrewed the tip, and epoxied the tip on inside, then I have no clue. :2: Hope this helps, and good luck on the L3!

 

[Golfpro62]

Thank You

 

[MasonH]

Now THAT is a colorful coupler my man.

 

[Golfpro62]

Isn't it though, I think Tim was running low on parts - it was Christmas present from my inlaws and I know he got it out fast so I don't mind. The airframe coupler is yellow too.

 

[stickershock23]

I Dont want to be a pooper. I have one of these and another very similar kit. (madcow Frenxy XL)

THe first on I built I used the bulkhead on the nosecone.. and MAN is it a fight to get my parachute into the upper bay. you can do it but it really has to go in perfect.

I built the Wild Thang second and the only change I made was to ditch the bulkhead. and use an Eyebolt to screw in the tip on the cone. then I tied shock cord right to it. gave me a LOT of extra room. I used that room to fold up the chock cord and stuff it in there. made getting my chute into the payload section much easier!

Now I Know you have a tracker in there. but I just thought I would share that with you! I LOVE my wildthang.... just too cool!


Oh and I got your message about decals for it.... shoot me an e-mail to remind my old forgetfull butt, and we will get you hooked up!

 

[EeebeeE]

One thing for sure...it will be the prettiest L3 attempt to ever fly. Eat a cosmic cucumber for good luck.

 

[Sailorbill]

Scott
Looking at your specifications I am thinking an 84" (7') Rocketman parachute might be overkill, especially in Argonia with an all fiberglass rocket.
His descent rate chart shows that with a 7FT parachute @15lb, 20.38Ft/Sec, 13.89 MPH and @23lb, 25.24Ft/Sec, 17.2 MPH.
In my experience Rocketman under rates his chutes.
Stuffing that parachute comfortably into a 4" tube might be a challenge too depending on what shroud lines you have.

Good luck on your attempt.
I hope to make AIRFest this year and will be looking forward to seeing it fly.

 

[troj]

Looking at your specifications I am thinking an 84" (7') Rocketman parachute might be overkill, especially in Argonia with an all fiberglass rocket.
His descent rate chart shows that with a 7FT parachute @15lb, 20.38Ft/Sec, 13.89 MPH and @23lb, 25.24Ft/Sec, 17.2 MPH.
In my experience Rocketman under rates his chutes.
Stuffing that parachute comfortably into a 4" tube might be a challenge too depending on what shroud lines you have.

We can get that parachute in there. It's all about how it's packed.

Push comes to shove, we pull out a Fruity Chutes toroidal. I happy to know where one of those lives.

-Kevin

 

[Sailorbill]

We can get that parachute in there. It's all about how it's packed.

Push comes to shove, we pull out a Fruity Chutes toroidal. I happy to know where one of those lives.

-Kevin

I figure you can get one in there but it looks like there will only be about 16" of airframe to put the chute, harness and protector in.
I also questioned if it was necessary especially with a fiberglass rocket.
Rich and I have flown quite a few rockets that weighed more than what Ky "recommended" and suffered no damage especially at Argonia.
+1 on the Fruity Chutes Isis toroidal. I know where I can lay my hands on one of every size from 36" to 96". :wink:

 

[stickershock23]

Yeah it can be done. but its gonna be a tight fit! thats why I mentioned I used the nose cone area to stuff my shock cord into.. made it a lot easier.. but again he needs room for tracking device!

 

[troj]

I figure you can get one in there but it looks like there will only be about 16" of airframe to put the chute, harness and protector in.

'tis why, at SLI, I often end up showing teams how to pack their parachutes....

I also questioned if it was necessary especially with a fiberglass rocket.

I'll be honest, I think a fiberglass rocket should be brought down just as slowly as you would any other typical rocket. It's a safety thing.

-Kevin

 

[Golfpro62]

I do also have a 72" Rocketman that I fly in my 4" Mad Dog that may be a better choice for this rocket. It will be solid so I am not afraid of it coming down a little quick.

 

[Sailorbill]

I do also have a 72" Rocketman that I fly in my 4" Mad Dog that may be a better choice for this rocket. It will be solid so I am not afraid of it coming down a little quick.

Scott my advice is worth what you pay for it. Sim it with both chutes and above all consult with your TAPS.

 

[Golfpro62]

I will sim it on the 72" and see what I come up with. Today is my oldest sons 21st birthday and my youngest was confirmed this morning so it's been a busy busy day and Dad's still got more to do for both these events. Tonight I will start posting on the Booster section.

Thanks to all of you for the advice and props, looking forward to getting some more done tonight - see you then.

 

[robbdm]

I did my L3 with a Wild Thang last year, ~13,500 on a M1278... used a Top Flight 84" easy fit, have also user 6' Recon chute easy fit built per Wildman instructions. Couldn't jam a Cert 3 large in there.

 

[Golfpro62]

Ok, I am back for a short time. I did sim this on both the 72" and 84" chute and see no reason why I couldn't use the 72" - it still comes down at a nice slow pace and would save me some room although I have stuffed the larger chute in the payload section without any problems, there is plenty of room.

As promised here is the start of the booster section. After test fitting the centering rings, I notched the upper ring to accommodate my recovery harness which will be epoxied to the motor mount. I dry fit all three centering rings, my Aeropack retainer, and all 3 fins taping them in place. If you don't get a nice tight fit for the fins between two centering rings you will end up with one heck of a mess when you start injecting the internal fillets (I learned this the hard way-more than once). For this reason I taped everything in place and tacked the lower 2 rings in place and when I was satisfied I went ahead and epoxied the Aeropack and two centering rings in place using JB Weld and let them dry overnight. Then I fit the top (notched) centering ring in place with a 10' section of 3/8" tubular kevlar running through the notches and down the motor mount approx 5" on both sides, this creates a loop that will run about a foot or so out the end of the booster section and to that I will attach my drogue shock cord (25' of 1/2" tubular kevlar) and drogue chute (a Rocketman 24" Mach II). Tacked the ring in place and finished by adding a good JB Weld fillet. I then mixed up some slightly thickened West Systems epoxy and laid down a good glob where the kevlar would lay down and then encapsulated it and left it to dry overnight.

 

[Golfpro62]

I don't know who invented the technique of injecting internal fin fillets, was it Tim Lehr or Crazy Jim? Who knows, but one thing I am convinced of is that it makes a rock solid rocket and saves a ton of time if you have done the prep correctly and I will never build a rocket without this method again. So, next step was to drill holes for injecting internal fin fillets. Earlier I had marked a spot 5 1/2" from each end of the slots a 1/4" away from the edges. I used a 1/4" drill bit for the job and then sanded the holes until they were free of any debris. If the holes are not clean, it creates issues later when injecting. While I had some 60 grit sandpaper in my hand I went ahead and sanded along both sides of the slots to ensure my external fillets have something to grab onto. I had already sanded these previously but I don't think you can over sand your surfaces that come into contact with epoxy (especially here). After all 12 holes were drilled and cleaned it was time to insert the motor mount. In the picture below you can make out where the top two centering rings are and I marked a spot about 1/4" above the ring. Later, after the fins have been attached and fillets finished, I will drill 2 more 1/4" holes in the airframe and inject fillets for the top 2 rings, then fill in the holes.

 

[Golfpro62]

This rocket will attain mach speed so this part of the build needs to be perfect, we have all seen big motors rip rockets apart - I don't want to see that. I took my time and tried to do it right. This is the fourth rocket I have used this technique on and I think I finally got it right. The trick is to make sure that the fins fit very tight between the centering rings, just a crack will let epoxy seep through and then run out someplace unexpected which also leaves a smaller fillet than it was meant to be. My fit was tight and the JB Weld I used for tacking the fins on is pretty thick stuff and I used it liberally which closed any gaps there might have been. I also taped all the other fins just in case it did seep through somewhere. But, the picture below says a thousand words - a perfect internal fillet! Not one drop out of place.

For each set of fins I mixed up 3 pumps West Systems resin and 3 pumps fast hardener for about a minute and then added some chopped carbon fiber to the mixture, a pile about the size of a dime or even a little smaller. It's amazing how small an amount will expand and to much ruins the mixture. I use a 10 ml syringe for injecting through the 1/4" holes I drilled earlier, one full syringe in both holes and one more evenly in both holes for a total of 30 ml per fin. I did two fins at a time while the rocket is in that position. After the first set was hardened I turned the rocket around and did two more fins and finally the last set. When everything works out perfect, you create a Dam for the epoxy, it is touching the fin, the motor mount, the body tube, and even the centering rings making everything very strong. Now it was time for external fin fillets.

 

[Golfpro62]

Just a question for everybody reading this: Do you all run out of hardener before you run out of resin?

Also, you might see in the background of some my pics this rocket from my childhood: the Starship Vega, man I can't tell you how much I wanted that rocket and how long it took to finally find one. I built that kit 35 years ago and it has never flown once. I saw more than one of these and also a Mars Snooper or two that really looked cool but never saw one survive a launch, so it just sat there looking good. Now I see them here and there but it was a rare find back then.

 

[Eat, sleep, and Fly]

Just a question for everybody reading this: Do you all run out of hardener before you run out of resin?


View attachment 127585

I always run out of resin before hardner :confused2:

 

[dcbertelsen]

Scott,

IIRC, there have been reports of the points of the 'W' snapping off during high speed flights. Are you doing something to avoid this or just hoping for the best?

Thanks for the build thread, I've been following closely. I hope to see this in the air this fall!

Doug

 

[Eat, sleep, and Fly]

Scott,

IIRC, there have been reports of the points of the 'W' snapping off during high speed flights. Are you doing something to avoid this or just hoping for the best?

Thanks for the build thread, I've been following closely. I hope to see this in the air this fall!

Doug

I don't think that there were reports of this, just speculation.

 

[Golfpro62]

Thank you for the concerns, I agree that these must have all been speculation. I have certainly discussed the issue with several folks including my TAP Members. The only news I have received so far is from people who also used this exact rocket or saw it fly for a Level 3 Cert with no problems what so ever. But, having said all that, when I get to the finishing of the fins, I will make sure I am doing what I can to make sure those W's in the fins are as aerodynamic as possible (think airfoil) just in case. The only other thing I would say on the subject is would Wildman Rocketry manufacture and guarantee for life a kit they thought couldn't take that kind of abuse, and then dare to call it "Extreme". Well, maybe we shouldn't answer that question about a guy named "Wildman" and his buddy called "Crazy". I certainly trust what they have designed here and they swear it is a non-issue.

 

[Golfpro62]

Ok, time to move on. It was time for the external fillets so I taped off all of the fins in preparation for the external fillets, just enough to cover up my internal fillet holes and all I could without running into the carved out "W" in the fins. For the external fillets. I mixed 2 pumps each of Wet Systems resin and fast hardener and added some 206 silica to thicken the mixture to the consistency of peanut butter. I spread it on generously the length of the fin and then used a tool (a piece of PVC tube dipped in alcohol) to pull smooth the fillets. After I was happy with the fillets I removed the tape. At this point I decided to drill my booster section vent hole: 1/8" located 22" from the top. Because the epoxy is so thick you need not worry about it running so you can immediately turn the rocket and begin on the next set. Since I mentioned alcohol I should note that during the course of this build I went through almost an entire container of rubbing alcohol and 3 full rolls of paper towels! Building rockets is a messy business.

 

[Golfpro62]

Although West Systems mixed with Silica make a great external fillet, they are a pain to sand smooth and I rarely spend lots of time on this. Usually don't care that much how they look I know they are very strong. Since this rocket will be somewhat on display (at least to you guys) I did want to make it look nicer than my rockets usually do. So, I used some Bondo Glazing Spot Putty, I really like this stuff and will use it again. Just put a dab on my finger and run it down the length of the fillet. It dries in about 20 minutes and then its easily sanded, I used 400 grit sandpaper, then repeated the process until I was satisfied that my fillets were nice and streamlined. It's not perfect but they are no doubt the smoothest and cleanest of any rocket in my fleet. After a coat or two of primer they should look pretty good. While I was working here, it was a good time to install the rail buttons too.

 

[Golfpro62]

Next it was onto something I really wasn't looking forward to - injecting the CR fillets. I was worried about the risk of punching through the tube and damaging the motor mount if not careful and then you have to fill in the holes. Some people attach a cup of epoxy to a dowel and pour it in but I am not that brave. I am worried that if the controlled spill is not perfect you pour epoxy right into the motor tube and honestly, that would suck! Injecting them seemed much more controlled. I took my time and didn't try to force it and I just broke through without even touching the motor mount. I cleaned up the 1/4" holes and injected 10 ml of West Systems with a little chopped carbon fiber mixed in. It made perfect fillets, now I just have to fill in the holes left behind. I used a small amount of JB Quick to fill the holes left behind. It's thick stuff so it stayed in place and covered the hole nicely, it sands very easy and it smoothed out very nice, you can't even tell the holes were ever there and now on to the next step.

 

[dixontj93060]

I've never injected CR fillets--kinda interesting.