Yet another Wildman Jr Build for Level 2

[AcadiaRockets]

I am going to build a Wildman Jr for my level 2.
I know, I know, there are a ton of build threads for these but since its for a certification I thought I would park my process; document techniques, ask for help, absorb any advice, here.

I bought this 2.1" kit, a 2.1" WM Eagle Claw Sport and a 2.6 WM V2 at the black Wednesday sale last year.


The thinking being the V2 would be my first fiberglass, and boat tail rocket, the Eagle claw would be 2.1" bigger longer faster, also boat tail, culminating with the WM JR 2.1 as my first 38mm and dual deploy rocket. And here we are. I am also studying for the exam which I would like to take at a club launch a full month before I launch.



I didn't get the WM Jr on purpose for the Level 2 as I thought it would go too high but a years worth of launches gave me confidence that it would be a good candidate, even if apogee will be over 6000ft.
So here goes.
Great kit - Tim has an awesome product. Washed everything in hot water and lots of dawn. Weighed parts and entered into Open Rocket. I am going to do a slim line tail cone retainer to sexy up the aft end a bit.


The biggest learning curve of THIS build will be the AV bay which is all new to me. I started collecting parts and that will be a big part of this build thread I anticipate.

 

[Buckeye]

Nice! No need for "low and slow" on a certification flight. I assume you are good at tracking and plan for a transmitter on board. Yes, the AV bay will be the most time-consuming part of the build.

On the other hand, though, ask yourself how many times you plan to shove a J-K-L motor in this little rocket once you achieve L2? If the answer is not very often, then maybe consider a bigger, Level 2-ish rocket to get more use of your certification.

 

[AcadiaRockets]

Thanks! I have been running a Featherweight setup since before my L1. I have about a dozen flights with that. AND since this build has the same nosecone as the Eagle Claw it all fits already.


I did get a head start on my av bay. I didn't want to publish that yet as to not get ahead of my self. I am using an RRC3, the matching Missleworks sled, Lab Rat pull pin switch. I have charge wells from Dog House, Bulkhead wire retainers from RocketJunkies, and e matches from Wildman. Its still not symmetrical but I will just keep the marginally shorter side aft and marginally longer side forward in the payload side fixed with the new PEM nuts from Apogee.

 

[Sandy H.]

I am going to build a Wildman Jr for my level 2.
I know, I know, there are a ton of build threads for these but since its for a certification I thought I would park my process; document techniques, ask for help, absorb any advice, here.
I bought this 2.1" kit, a 2.1" WM Eagle Claw Sport and a 2.6 WM V2 at the black Wednesday sale last year. The thinking being the V2 would be my first fiberglass, and boat tail rocket, the Eagle claw would be 2.1" bigger longer faster, also boat tail, culminating with the WM JR 2.1 as my first 38mm and dual deploy rocket. And here we are. I am also studying for the exam which I would like to take at a club launch a full month before I launch.

I didn't get the WM Jr on purpose for the Level 2 as I thought it would go too high but a years worth of launches gave me confidence that it would be a good candidate, even if apogee will be over 6000ft.
So here goes.
Great kit - Tim has an awesome product. Washed everything in hot water and lots of dawn. Weighed parts and entered into Open Rocket. I am going to do a slim line tail cone retainer to sexy up the aft end a bit. The biggest learning curve of THIS build will be the AV bay which is all new to me. I started collecting parts and that will be a big part of this build thread I anticipate.

The Eagle Claw Sport is beautiful! Great chute as well. Looking forward to seeing what you do on the Jr.

Lastly, my wife and I greatly enjoyed our driving trip through Maine. You can keep the Moxie, but she loved the blueberries and a particular shop in Bar Harbor that had lemon/blueberry whoopie pies.

Sandy.

 

[Hobie1dog]

I am using an RRC3, the matching Missleworks sled, Lab Rat pull pin switch. I have charge wells from Binder and e matches from Wildman.

All top of the line stuff.

 

[AcadiaRockets]

The AV bay.
As I alluded I started with the AV bay first. Since it was the thing most different from any of the other rocket stuff I had done I wanted to over research this.
I started gathering parts 6 months ago piece by piece. The length and width of Wildmans fiberglass tube was fixed. I wanted to use the MissleWorks RRC3 and the 54mm sled that fit it had #10 all-thread space.


I bought the all-thread and a fist full of nylon bushings, regular nuts, acorn nuts, lock and reg. washers and wingnuts.


After measuring the all-thread going from one end to the other, thickness of the bulkheads and enough meat on either end for the acorn nuts on one end and wingnuts on the other - the all thread was dremeled to length.



Problem - The sled fit in nicely but no combination of my nylon bushing on one end or the other put the built in location for the cool rotary switch that came with sled anywhere in the middle "half" of the av bay. There was never more than an inch on one end or the other after the vent band. That would not do. The switch would have to move closer to the middle of the sled negating the dedicated space in the 3D sled.
I had always wanted to use the cool pull pin switch I had seen in bigger rockets.
Once I gave up on using the built in rotary switch I just found a flat location on the back of the sled and screwed in on after backing it with a cut of piece of foam emery board to raise it above the all thread.

Now with pushing the sled all the way to one end and stacking the bushings on the other the pull switch pin goes through the vent band near the middle. Near; one side is still a little shorter on one side of the vent band and that will be the fore end.

 

[AcadiaRockets]

AV bay continued . . .
The bulkheads have a center pilot hole and two for the all-thread.

With those all drilled out the sled and switch oriented well a couple adjustments were made. The sled would not abut the bulkhead as the now not use switch space was in the way. I dremeled away parts of the sled so the sled would clear the charge well nut and/or the bulkhead wire retainers. I hope jamming the one end against the bulkhead isn't bad?

The charge wells. I REALLY wanted to use the cool integrated Dog House charge well and mount kits. I got a couple sizes. Without having done dual deploy before charge amounts was nothing I had experience with. Looking at calculators, others stories, advice, so many you tube videos I still didn't know how big i should expect until I ground tested. So I got the Rocket junkies 3 gram charge wells, and the Dog House designs 1.5 wells. I positioned the 3 gram on the bulkhead and drilled for those then mounted the 1.5. But the hole with fit either if 1.5 grams is not enough. How much powder have other used in Wildman Jr's?

I also wanted to put knurled finger screw leads like big rockets on the bulkheads but it was getting full on the 54mm bulkhead so I decided on the Rocket Junkies Wire retainers to save space.
The av bay was coming together. The 9vt lead I had was 24 gauge so I bought more of that wire to match the wires to the switch. I had never soldered before so I bought a kit on Amazon and learned to tin the ends and soldered the wires to the switch and put some heat shrink over that. I twisted all the wired from the switches and battery and ran them under the board. This was all the newest stuff to learn and I was pretty proud of myself. What else am I missing?

 

[AcadiaRockets]

More AV bay
I don't want to drill the holes on the vent band until I am further along in the rocket unless there is something I am not thinking about that will make the orientation difficult. So I will wait to epoxy the vent band on and drill the holes. I think the two holes for the pull pin will be enough to vent the bay for the RRC3. Tell me if that's bad?


I test fit some ematches and curled them around a pencil to keep it clean looking.
I image I will run the RRC3 with the default apogee and 500ft settings. I got the blue tooth dongle and down loaded the mDACS software and have been familiarizing myself with that.
Also been studying for the Level two written test.


Black powder! Geez! Where to find black powder. My foray into dual deploy could have been short lived If I could not find black powder.
Like I said I have been gathering parts for six month and could not find ANY fffg. Well I COULD buy a 4 pack and pay $60 haz mat. Minimum order with multiple bottles and shipping was hundreds of dollars. Yet I had that in the shopping carts of three stores around the country. I got a couple offers of other club members to share but didn't want to take their valuable stash either. Then my resourceful Prefect found some at a mom and pop shop local to him and saved me. After looking for half a year I had the last thing I needed. Powder acquired!

 

[waltr]

Build is looking good. I would shorten the ematch leads when doing the real install. Strip the wire ends just long enough for the terminal blocks. The wire you cut off is good for making motor igniters.
This WM Jr is about the same size as my LOC 2.2" LOC IRIS. I use 0.8gram BP for the drogue and 1.2gram BP for the main with one 2-56 nylon shear pin on the nose cone. You will want the nose cone held on with a shear pin, maybe 2 of them if the nose cone is more than 100 grams.

 

[AcadiaRockets]

I would shorten the ematch leads when doing the real install. Strip the wire ends just long enough for the terminal blocks. The wire you cut off is good for making motor igniters.

thanks! that will look cleaner than my coils. And a good source of the right wire!. I bought the igniter materials and have been making them from leftover club launches.

I use 0.8gram BP for the drogue and 1.2gram BP for the main

Glad i am in the ballpark with the 1.5 wells. Only ground testing will tell for sure.

one 2-56 nylon shear pin on the nose cone. You will want the nose cone held on with a shear pin, maybe 2 of them if the nose cone is more than 100 grams.

Now I will weigh everything in the nose cone tonight. It is the Wildman nosecone, with and additional eyebolt replacement in there AND I am putting the Featherweight altimeter in there so the NC will be heavy.

 

[waltr]

Now I will weigh everything in the nose cone tonight. It is the Wildman nosecone, with and additional eyebolt replacement in there AND I am putting the Featherweight altimeter in there so the NC will be heavy.

Seems the Nose will be over 200 gram. I would plan on 3, 2-56 screws as shear pins (may only need two). Then you may need over 1.2gram BP but as you said, Ground test.

I have been putting 2, 2-56 threaded holes in but have only used one screw to hold nose on.

 

[AcadiaRockets]

Nose Cone
I weighed the nose cone and its over 200 grams so two three 2-56 shear pins is what I am hearing?
The nose cone will have the Featherweight GPS in it.


When I did the Eagle Claw which I have not flown yet, I wanted to use the strength of the eyebolt I epoxied into the aluminum tip and be able to use the Lab Rat FW GPS NC mount. The eyebolt does nothing here but give me a convenient thing to hold.

I came up with the rig you see in the Eagle Claw pictures attached. The thinking is on ejection the forces go past the Lab Rat sled and only pull on the aluminum tip. Nothing gets attached to the outside of the eyebolt.


Please suggest if this is a bad idea? Also looking for advice on screws to secure the Lab rat sled inside the nose cone shoulder.

On the Eagle Claw I have allen screws that I just back in and out from the inside.

 

[AcadiaRockets]

While I am on the subject of Featherweight tracker installation and drilling holes. I couldn't find anything definitive in the manual or with a quick search. . . .

DOES the Featherweight GPS need to be vented? Do I need to drill holes for the atmosphere in the nosecone? Its all Satellites yes? No barometric part of the GPS I think? OK for it to be sealed up in there?

 

[waltr]

As far I can tell this is GPS only with no Baro so no need for vent holes.

The cord going past the tracker sled to the eyebolt on the tip is a good idea. Then no stress is put on the sled and you do not need much to hold the sled into the nose cone.

 

[cbrarick]

not certain what weight you have for the nose cone (I'm American so I don't speak metric)
However, my JR was my L2 and I've flown it on almost every motor that will fit that's a I or better
I only have one shear pin in mine and use all thread to the bulkhead

I do have a question - will you have problems with the telemetry if your antenna is right up next to the metal tip?

My simple solution was to take a LOC 2 inch coupler and stiffy tube, glue bulkead on each of them then pin them together with a rivet this makes a nice small compartment you can put your gps in, wrapped in some bubble wrap. On one bulkhead I put a eye bolt for 12" Kevlar, then i move it from rocket to rocket on a quick link

 

[rocketgeek101]

Nice build!

I do have a question - will you have problems with the telemetry if your antenna is right up next to the metal tip?

I have flown my Featherweight GPS mounted right next to a long length of threaded rod. It doesn't care. The metal nose tip certainly won't be an issue on a rocket like this.

Nose Cone
I weighed the nose cone and its over 200 grams so two three 2-56 shear pins is what I am hearing?
The nose cone will have the Featherweight GPS in it. When I did the Eagle Claw which I have not flown yet, I wanted to use the strength of the eyebolt I epoxied into the aluminum tip and be able to use the Lab Rat FW GPS NC mount. I came up with the rig you see in the Eagle Claw pictures attached. The thinking is on ejection the forces go past the Lab Rat sled and only pull on the aluminum tip. Please suggest if this is a bad idea? Also looking for advice on screws to secure the Lab rat sled inside the nose cone shoulder. On the Eagle Claw I have allen screws that I just back in and out from the inside.

On my Shape Shifter Jr (same rocket, different fins) I used two 2-56 shear pins for the nose and that is plenty. I ran a length of threaded rod from the aluminum nose tip to the nosecone bulkhead and 3D printed a sled that slides onto the threaded rod to mount the GPS in the nose. Mine is also an older version of the kit that uses the thicker (heavier) fibreglass components that Wildman used to use. I use 1.5g BP charges for both apogee and main and that seems about right.

 

[AcadiaRockets]

I do have a question - will you have problems with the telemetry if your antenna is right up next to the metal tip?

I set it all out. Looks like the very tip of the antenna is still 7 inches away from the end of the eyebolt.

I am thinking that's good? This is the same setup on My Eagle Claw Sport and even though it has yet to see its maiden flight, I will have flown the Eagle Claw a couple times before this Wildman Jr. level 2 flight happens for proof of concept.

 

[waltr]

Yes, eyebolt and nose tip is plenty far enough away from the telemetry antenna. No problems there.

Other good advice posted about shear pins and BP charge amounts.
The shear pins on the nose is to prevent main deployment when the Drogue charge fires. The worst that can happen is main gets deployed at apogee and rocket drifts farther than planned. Good reason to keep first flights lower and fly the field as if main will deploy at apogee.

Then in the ground tests--Have the nose shear pins in, with everything loaded above the ebay. Test fire the Drogue. What you want is the Ebay + main + nose to eject and stay together in one piece.
What can cause the nose to separate is the cord fully extending with velocity then stopping suddenly. If this happens then the drogue charge is too large.
It does help a good amount to either do taped bundles or braid the cord. This absorbs energy and help prevent the sudden stop when the cord fully extends.

 

[AcadiaRockets]

Motor Mount
I tacked on the centering rings with a drop of CA after determining how far it would have to stick out to accommodate the SlimLine retainer and defining distance between top and bottom of the g10 fins.
With the mm in position I used a G2 gel pen refill to mark through the fin slots where the fins hit the mm.


Then I cracked off the fore centering ring and ground out spaces at 180 degrees for webbing to pass through.
I bought a bunch of yards of 1/2 inch kevlar webbing that is my go to for my Y harnesses. I cut off a length of that to pass through the fore centering ring and just touch the aft ring.


The length is sized so that I have enough hanging out the booster to attach a pinch ring and swivel to attach the One Bad Hawk kevlar 20ft shock cord to.


Positioning the fore centering ring with it 180 degree spots for the harness and avoiding the marks for the fins at 120 degrees I marked a path for the 1/2" kevlar web.
I glued these down with BSI 30 min.

 

[AcadiaRockets]

Nose cone continued
Having epoxied the eyebolt into the aluminum tip I taped the outside of the nose cone and shoulder to make cleanup easier.

I sanded the inside and outside with 80 grip wrapped around a rubber spatula (patent pending). Then BSI 30 min epoxied the surfaces and removed the tape.


I should mention before I did that I slipped the shoulder inside the fin slots and marked the shoulder at exactly 120 degree marks to easily find where to drill the shear pin holes later.

 

[AcadiaRockets]

Installing Nose cone attachment
I showed earlier what I did to the Eagle Claw to accommodate the attachment point while staying out of the way of the Featherweight tracker and Lab Rat sled.


I fished a smaller string down to the eye, pulled though with a coat hanger, tied it to the kevlar I am using for the attachment and pulled it through.



Then square knot, CA drops, and heat shrink tube to hold all that together. Pulled the knot to the top of the nose cone and there ya go!


Lastly i put on a swivel and little piece of heat shrink tube to keep it tidy.

 

[AcadiaRockets]

Rail Buttons and Motor Mount.


I like the Apogee rail buttons. I like that they have the back and they slip inside the button itself. The back it so low profile I can even slip the motor mount past it at an angle when installing.


So the aft button is as far back as it can be without the back touching the aft centering ring. I used a straight edge to line up the fore button which is a caliber clear of the furthest aft the av bay is inside.


Again I like the super low profile of the Apogee t nuts. they don't get in the way of parachutes at all.

I sanded the inside and outside of the fin slots before I actually epoxied the motor mount in.



And after all the rail buttons were glues in I put a generous amount of BSI 30 min and slid the motor mount past the aft button pushing the epoxy forward to what I imagine is a beautiful fillet on the top of that forward centering ring since I cant see it.
With the motor mount positioned just so that the Slim line mounter mount is lined up I let it dry. Once dry I will slip off the retainer and pop out the aft centering ring to expose the inside to do fillets after the fins are double dipped epoxied.
Still reading over my Level 2 test to prepare for that.

 

[AcadiaRockets]

installing Fins
I still like my Estes fin jig. I use it for my LPR and HPR. I also like the Qualman Rocketry fin alignment guides. Both have their limits but together they are great to be sure they agree.
I have had to make some extra adapters for the Estes tool from 13mm to 18mm, 18mm to 24mm, 24mm to 29mm, and finally 29mm to 38mm. The last was I made spacers with paper towel roll tubes.

Now that the motor mount is in and sticks out the end enough to accommodate the slim line retainer AND nothing is in the way to epoxy the fins in I applied the double dip technique and epoxied the fins in with BSI 30. I did them all at once and let dry over night.

The Estes holds the fins at 120 degrees from a wide angle. The Qualman also holds them at 120 degrees but since the Qualman can't slide down any further it does double duty holding the fins tight against the motor mount.

 

[AcadiaRockets]

Shoring up fin attachment.
Anyone who followed my struggle with expanding foam from the Eagle Claw build to the point I thought the rocket community was hazing me by thinking expand foam was a thing will be glad to hear through practice, OCD steps to the point of performance art and lots of wasted foam I got a technique down.
I will not just photograph this I will video it, as is very fast. Also from the last rocket I know it WILL find any gaps in the fins to squirt out.
So even though I plan to make some beautiful fillets with rocket poxy I made teeny fillets with BSI 30 JUST to seal all the gaps. I will let that cure for a day, sand lightly, then do the Rocket poxy. Then I will do the expanding foam before reinstalling the aft centering ring and then the Slim Line retainer.

Still studying for the written test too.

 

[wsume99]

The routing and attachment of your recovery harness eliminates the need for the eyebolt on your NC so why have it there? Am I missing something?

 

[AcadiaRockets]

The routing and attachment of your recovery harness eliminates the need for the eyebolt on your NC so why have it there? Am I missing something?

Good question. No, you nailed it. I even say in the post its not necessary. I could replace it with a 1/4 lag or even a nylon screw to keep it lighter. The eyebolt was just what I had and its convenient to hold onto. Anyone have any sexy ways to terminate it for quick removal? I may have to switch the Featherweight between rockets fast so the eye is easy to grasp?

 

[wsume99]

Good question. No, you nailed it. I even say in the post its not necessary. I could replace it with a 1/4 lag or even a nylon screw to keep it lighter. The eyebolt was just what I had and its convenient to hold onto. Anyone have any sexy ways to terminate it for quick removal? I may have to switch the Featherweight between rockets fast so the eye is easy to grasp?

Having something to help remove the electronics was the only reason I could see for keeping it. The simplest thing is probably to just leave it as is. If it was my rocket I'd probably plug the tapped hole with a nylon screw and then figure out a way to add a small kevlar loop to the bulkhead so I could pull it out. It wouldn't even need to be a loop. You could just drill a small hole thru the center of the nylon screw and add a short piece of kevlar kite string knotted on both ends. Hopefully that makes sense.

 

[AcadiaRockets]

Having something to help remove the electronics was the only reason I could see for keeping it. The simplest thing is probably to just leave it as is. If it was my rocket I'd probably plug the tapped hole with a nylon screw and then figure out a way to add a small kevlar loop to the bulkhead so I could pull it out. It wouldn't even need to be a loop. You could just drill a small hole thru the center of the nylon screw and add a short piece of kevlar kite string knotted on both ends. Hopefully that makes sense.

Bulkhead stays, The sled needs to screw out for quick swapping. I could use a short lag or nylon screw but them I would need to carry a screwdriver or wrench.

 

[wsume99]

Bulkhead stays, The sled needs to screw out for quick swapping. I could use a short lag or nylon screw but them I would need to carry a screwdriver or wrench.View attachment 541333View attachment 541332

I see. Like I said, the simplest thing is to just use the eyebolt if you want to avoid carrying any tools.

 

[pathtouch]

Looking good! Think you’ll be ready in a couple weekends?