Wildman Eagle Claw 4 Winter Project
 

Hi All,

Hopefully you're having fun in your workshop assembling rockets for this spring and summer!!

After successfully achieving our L2 cert last year Nate and I are going bigger and more complicated prior to an L3 cert attempt.

We chose the Widman Eagle Claw 4 as a great kit to test our building techniques and to add more complex electronics.

With the 54mm MMT we hope to go as big as an Aerotech L1000!

Here's what we are trying with this build:

• Redundant dual altimeter triggered ejection charges
• Additive aerospace SMART sled
• Trackimo tracker
• Additive aerospace external shroud for camera
• Mobius 1080HD camera

Matt

Build Progress
 

Hi All,

Only snafu with the kit was a tail cone that was about 4 inches too long. A quick email to Tim and Jackie resulted in their typical friendly and prompt reply and shipment of the correct sized tail cone.

This kit is interesting as it has a 36" MMT that needs to run from the bottom all the way up to beyond the front fins. We had to Dremel out the fin slots a bit to get a perfect fit. Also had to Dremel out a portion of the connector tube that links the tail cone to the booster section. There was some overlap.

We attached an Aeropak retainer to the bottom of the MMT followed by 3 centering rings.

For the recovery cord we've been using nylon strap and using an awl to sew our own loops. After making some notches in the forward centering rings we ran the nylon recovery strap under and epoxied against the MMT.

Matt

Build Progress 2
 

Hi All,

Forgot to mention that before actually setting the forward centering rings and recovery strap we fixed the MMT into the tail cone. We fixed the Aeropak retainer and one centering ring to the MMT and then epoxied it into the tailbone. Epoxied the tail cone connector in place, used the Dremel to widen the fin slots and then moved on to fixing the fins.

We then got to use our new toy: Gorilla Guillotine Fin Jig!!! Wow this fin jig is awesome and easy to use... worth every penny. To keep everything in alignment we

We used Great Planes 30 minutes epoxy and ran internal fillets prior to foaming the fin can with Public Missles Ltd. Adjustable Density Foam.

We played around with the foam as instructed filling solo cups prior to foaming the tail cone. We decided to not add any water just a 1:1 mix of parts A and B. It took a couple of additions, waiting for it to solidify between each pour. The hard part was digging out the overage to make sure the centering ring would sit down evenly on the forward edges of the fins.

This was our first time foaming a fin can and it seemed to work out well. Not sure I would be comfortable using this technique on anything but fiberglass.

Matt

Build Progress 3
 

Hi All,

Ok, with the tail cone fins fixed and foamed it was on to the booster fins. We had a couple of assembly challenges:

• Rail button placement
• Alignment of tail cone fins with forward fins
• Length of the rocket relative to the fin jig
• How to set internal fillets on the forward fins?

I'm sure there's different ways to solve these build issues. Here's how we tackled them:

We first fit the tail cone and booster sections together but not completely. There was enough room in the gap between the two sections to fix a 1515 rail button using a T nut embedded in wood through the tube wall. We did not epoxy the forward centering rings at this time.

When we fixed the tail cone fins using the fin jig we had also dry fit the forward fins in the booster section so they would be aligned. We placed tape across the seam between the tail cone and booster section which was then cut at the seam with a razor blade. By numbering each of the 3 sections of tape we had a way of realigning the airframe tubes for the final assembly.

We then ran a thin layer of epoxy around the tail cone connector tube pushed the sections together and made sure to align the tape markings. We placed the airframe back in the fin jig, dry fit a forward fin and clamped everything in place to ensure a straight and tight fit.

Because we had to widen the forward fin slots a space was left to run epoxy along the centering rings and airframe wall. So, we were able to make internal epoxy fillets without any additional drilling of holes.

Matt

Build Progress 4
 

Hi All,

So the double fin set was not a perfect fit even for the Gorilla Guillotine fin jig, but we made it work.

After setting all of the forward fins it was time for external fillets.

I must say that the fin jig was amazing and the alignment of the tail cone and booster fins appears perfect. I guess will find out when we launch it!

For this bird we went back to our prior method of making external fillets:


We use some heavy grit sandpaper (80-100) to roughen up the airframe and fin areas then use 3M painters tape to mask off the fillet.

• Great Planes 30 minute epoxy
• West systems fiberglass
• Phenolic microballons
• Formula that seems to work for us is 7.5ml resin, 7.5ml hardner, 1 teaspoon fiberglass, 1 teaspoon micro ballons

Epoxy mixture is poured into the fillet area and then smoothed using a piece of 1" PVC soaked in rubbing alcohol. We only allow it to set about 5-10 minutes before pulling off the tape and then smoothing the epoxy with a gloved finger soaked in rubbing alcohol.

Using this technique we were able to get 4 fillets done in about 30 minutes and all 12 cast in 3 days.

The next step is obviously the dreaded sanding. We like to use the 3M flexible 150 and 320 grit sand paper. After fairly aggressive sanding to smooth down the edges we apply a generous amount of Elmers color changing wood filler. The wood filler helps to fill in those gaps and imperfections and is easy to work with. After letting the wood filler set overnight it was lots more sanding to take the filler down to almost nothing.

Cleaned up the booster/tail cone section with a wipe down using rubbing alcohol soaked paper towels and then set it aside to wait for painting weather.........

Matt

Build Progress 5 - AV Bay
 

Hi All,

With the tail cone/booster section assembled we moved on to the AV Bay.

Additive aerospace SMART sled

Perfectflite CF altimeter

Missleworks RRC2+ altimeter

Dual rotary switches

Dual DogHouse Rocketry ejection charge cannisters

I'll post some additional pics when we figure out how to anchor the Trackimo tracker.

Cheers!

Matt

a power sander works well for sanding FG and saves your arm :).
Rex

Hi Rex,

I haven't found a power sander that can safely get into the fillets. I have tried wrapping the SP around a 6-8" piece of PVC. A little soreness reminds you that you put some effort into the job.

Hope your winter is going well.

Matt

Build Progress 6 - Complete load Cg test
 

Hi All,

Aren't you glad we don't live on the East coast right now!!!!

So here's what got done this last couple of weeks:

• Added the forward rail button
• Added about 150g of steel shot to the nose cone tip
• Epoxied the coupler to the nose cone
• Drilled out vent holes and the holes to attach the payload section to the AV Bay
• Test mounted the camera shroud to the payload section

So with pretty much all the build elements done it was time to load up the bird with all recovery gear and a K540M motor in a 54mm/1706 case and test for Cg.

The attached pics show the rocket balancing at the Cg, which turned out to match almost exactly where the OpenRocket simulation estimated the Cg. With the K540M motor it results in about 1.4 calibers of stability. When we move up to a 54mm/2560 motor we'll lose a little and might have to add a little more nose weight.

So now we just wait like everybody else for the 50 degree days when we can start painting in the garage and then land testing the ejection system.

Looking forward to the Bong!!!

Cheers,

Matt and Nate

Hey matt/nate, nice rocket. I built the same about 2 years ago. Mine also came with a long tail cone but I opted to keep it and add a longer MMT & of course Tim sent me a new one immediately.
Biggest motor I have flown in it so far was an L990.
I see you added nose weight. Mine didnt need any - it's very stable without it.!

Eagle Claw 4
 

Hi Tim,

Thanks for the comments! I'm guessing that the rather massive fin area provides plenty of stability and we will launch off the taller 1515 Rails.

Looks like you also mounted a camera and shroud on your payload section.

What did your final loaded weight turn out to be ?

What altitudes did you achieve on the L990?

Cheers

Matt

I initially had 1010 buttons but when I flew the L motor, I had to put the 1515 buttons on it as our away cell only had a 1515 rail.

The fully loaded weight with L990 was 21.0 lbs. No motor, 16.1 lbs.
Altitude on the L990 was 7173'.

I like the camera on the payload as you can see apogee events.

Few comments about deployment - while under drogue the booster spins like crazy. Drogue harness was really twisted. Have seen the same on a few other rockets with the big fins. I ended up putting a swivel on the drogue harness hear the booster which helped significantly but it didn't totally eliminate the twist.

Here is a video with a K780. Look close after apogee & you will see how twisted harness gets. This was before I added swivel.

https://youtu.be/C8xC69LnMUg

Build Progress 7
 

Well a little warm weather in late February allowed for the start of painting. Decided to go with a Red White and Blue theme with gold decals from StickerShock... stay tuned I think this bird is gonna be pretty..

Painting:

• Sanded the entire rocket with 320 grit 3M paper to remove all residues of epoxy or other imperfections
• Cleaned up with a thorough wipe down with isopropyl alcohol (rubbing alcohol) soaked paper towels
• Removed all particulate traces with a gentle rub down with a tack cloth
• Using a sandable auto primer (Plasti-kote)
• After an overnight dry more sanding - this time wet sanding with 320 grit 3M paper
• Two to three total primer layers prior to starting with the color coats
• Plan is for a high gloss finish so using a combination of Testors Lacquer and Rustoleum Lacquer paints
• Applying modest to light lacquer color coats followed by overnight drying and then sanding
• Water wipe down and tack cloth rub down between each cycle of color coat application and sanding
• Using 1500 grit 3M paper on the color coats
• 2-3 color coats with sanding in between prior to application of decals
• Final coverage will be with a clear coat lacquer

Hoping that we are finally hitting consistent 50F+ weather so I can finish the painting this week!!!

In between painting I finished off the AV bay. The last component was to mount the Trackimo GPS tracker. The Trackimo comes with 2 different back plates; 1 with a belt clip the other with Velcro. Added Velcro strips to the AV bay sled and a plastic backing plate so it won't pop off with acceleration at launch.

Next steps.... finish color coat painting, adhere decals, final clear coat painting, weighing and final Cg determination, dry land ejection charge testing.

Will follow Tim's advice with respect to swivels attached to the parachutes.

Have a K540M motor ready for first flight!!!

Cheers all!

Matt and Nate

Eagle Claw 4 Complete!
 

Well finally a nice warm weekend for applying the decals and finish painting with clear coat lacquer.

Decals are from Sticker Shock and they are awesome! Thanks Mark!

Now it's just arranging schedules so Nate and I can test this bird out at an upcoming Woosh launch.

Hope we see you there!



Matt and Nate

Wow! Lookin' spiffy!


Joe

Have you had a chance to launch it yet?

Spring in WI is a drag
 

Hi Tim,

No launches yet. This last weekend was to be the first, but another cold wet and windy weather front scrubbed the launch.

Ejection charge ground testing is complete just waiting for Mother Nature to help out.

Matt

First Flight!!!
 

Finally!!!

A free Saturday, great weather and a launch sponsored by Tripoli Wisconsin Assoc. let us complete our first flight of the Eagle Claw 4.

Set up included redundant altimeters for dual deploy parachute recovery. This bird topped out just over 19lbs so we didn't want to risk a lawn dart.

A few pics are attached below and the video is posted here on our YouTube channel. .

Reached 3636ft and recovery was perfect except for the tree that it landed in. Fortunately we were able to pull it down without any significant damage to the tree!!!

Next launch will be on a K480 (2273 Ns), should be fun!

Matt and Nate

Congrats! Nice boost too!