So It Begins, Wildman Blackhawk 98 Build

[Bobrogg]

My Balls 32 project, a Wildman Blackhawk 98. I will be using Fluctus GPS system as prime w/ RRC2+ as backup for electronics and using Rouse-Tech CD3 system for deployment. Valkyrie recovery gear for drogue and mains, the motor will hopefully be a CTI N1100 (availability dependent).

 

[Hobie1dog]

cool, keep the pictures coming.

 

[cwbullet]

Subscribed. I have one of these to build and can't wait to see how you do it.

 

[rfjustin]

O-1100???

 

[Bobrogg]

O-1100???

fat fingered the entry, n1100

 

[Aeva]

fat fingered the entry, n1100

obligatory "O sad"....

 

[tfish]

I saw that and figured it was a '"CTI" Research motor'..it's Balls after all..

Tony

 

[Bobrogg]

Putting the fins on using a small bead of JB weld and using CA at the tips to hold it in place during the cure. Thanks to @rfjustin for this build tip.

 

[Bobrogg]

Coupler build using the leftover JB. Note when I hold the coupler up to the sun and you can see the JB weld coverage under the switch band. I purposely twisted the band around the coupler to get the epoxy evenly spread. I still see gaps and voids, but I think this will be more than enough to hold up under launch.

 

[Bobrogg]

ready for fillets, still debating on using JB weld or proline 4500. I like the JB just because cleanup is so easy, and it doesn't slump during cure allowing you to do all the fillets in one build session.

 

[rfjustin]

ready for fillets, still debating on using JB weld for proline 4500. I like the JB just because cleanup is so easy, and it does slump during cure allowing you to do all the fillets in one build session.


View attachment 633081

4500 for the fillets if you have it.

 

[Bobrogg]

Drat, the carbon fiber I have on hand is not wide enough for a true tip to tip, I do have 6 oz glass that will work but I believe that would be one of the 10 commandment sins in the rocketry world for putting glass over carbon fiber.

Still debating on using west system 105 or aero poxy for the tip to tip. I have the west system here but would need to order the aero poxy.

 

[UPscaler]

Drat, the carbon fiber I have on hand is not wide enough for a true tip to tip, I do have 6 oz glass that will work but I believe that would be one of the 10 commandment sins in the rocketry world for putting glass over carbon fiber.

Still debating on using west system 105 or aero poxy for the tip to tip. I have the west system here but would need to order the aero poxy.

View attachment 633082

You could always do nice big fillets and go without the tip to tip!

 

[Bobrogg]

First of three fillets done today using Proline 4500. I am not a fan of this epoxy because of the mess it can make (user fault). A pro tip, baby wipes are a god sent for cleanup. It will remove the wet epoxy from your hands without having to use harsh chemicals, also really good for post launch motor/rocket cleanups.

 

[ljwilley]

Looks amazing! Keep it up, lots of photos please!

 

[Absouloot]

I think this is more of a community question. I am not at this level of build yet, so I am not sure I understand at what point to you need or want to use a glass from "tip to tip"? Those fillets look really good, and as good as they look, would you still need or want to glass it?

And I second the request for more photos please!!

 

[Bobrogg]

I think this is more of a community question. I am not at this level of build yet, so I am not sure I understand at what point to you need or want to use a glass from "tip to tip"? Those fillets look really good, and as good as they look, would you still need or want to glass it?

And I second the request for more photos please!!

It's done to help with fin flutter at Mach 1 and above as well as helping with a hard landing. A N1100 sims out to Mach 1.5 and a N2500 to Mach 2.1 so tip to tip is really needed.

 

[Absouloot]

It's done to help with fin flutter at Mach 1 and above as well as helping with a hard landing. A N110 sims out to Mach 1.5 and a N2500 to Mach 2.1 so tip to tip is really needed.

Thank you!!!
So... then my next question is, glass from tip to tip versus thicker or stiffer material for the fins? I am thinking maybe the glassing would do more for the entire construction with a stiffer or stronger aft section. I have only assembled one rocket with G10 fins (fillets only because it was MUCH smaller and not going to get to Mach anything!), not sure how G10 would compare to carbon fiber fins! I would think the different carbon weaves could give the fin a lot of rigidity if done right. Or is carbon not used as much just because of cost or brittleness?

 

[David Schwantz]

I know I am just a dumb hick that drives a truck, but I cannot see any prep, sanding, on fins or tube.

 

[StreuB1]

Did you scuff the tube and fins before epoxying in place??

If not, you will want to break/cut them off, remove all epoxy, prep, and start over.

 

[Bobrogg]

Did you scuff the tube and fins before epoxying in place??

If not, you will want to break/cut them off, remove all epoxy, prep, and start over.

Yes, I hit all surfaces with 120 grit sandpaper using my orbital sander and then wiped down with isopropyl, the tubes i sanded just the areas where the epoxy was going down. For the tip to tip i plan on sanding more of the tube as well as the fins prior to putting down the cloth.

 

[David Schwantz]

Glad you sanded surface. I know everyone has their own way of doing prep, and none is really wrong, but I like more coarse grit. Good luck with build and flight.

 

[cbrarick]

subscribed. I'm doing a Falcon 98 for my Balls project

One thing I learned at last year's Balls was that good fillets using a quality structural adhesive make tip to tip unnecessary. A friend went M4.3 before his nose cone imploded, the rocket turned left and came in ballistic. We dug it out of the playa and the fins were still intact. He used DP-420 and no tip to tip.

 

[UPscaler]

subscribed. I'm doing a Falcon 98 for my Balls project

One thing I learned at last year's Balls was that good fillets using a quality structural adhesive make tip to tip unnecessary. A friend went M4.3 before his nose cone imploded, the rocket turned left and came in ballistic. We dug it out of the playa and the fins were still intact. He used DP-420 and no tip to tip.

Yep! That flight was so close to making it. There's a couple of other flights that come to mind under the same principle. Tony Pipe's MD O3400 went north of Mach 4 and folded the coupler, but the fins were still attached after coming in ballistic. Similarly, Steve Heller and Manny Ballestero did over Mach 5 with surface-mount-only fins at BALLS a few years ago and unwound the nosecone.

I've personally gone well north of Mach 1 with only JB Weld and I plan to push that even higher with a 3" M flight in the near future.

 

[cbrarick]

did i miss it or what are you doing for motor retention?

 

[Bobrogg]

did i miss it or what are you doing for motor retention?

I have not gotten that far yet but it will be simple and strong

 

[Bobrogg]

A short post today, winter weather has me preoccupied with household chores. I'm really liking the fillets results but really hate the mess. I did hit the epoxy areas again with the orbital sander prior to the fillets, one more fillet to go and then the focus shifts to motor retention and ebay fabrication.

 

[Bobrogg]

Finally, the last fillet completed. When they say this proline 4500 stuff gets everywhere they are not joking....

 

[Bobrogg]

Sorry for not posting sooner, work has me very busy as of late. here I have completed the tip-to-tip carbon fiber of the fins. two layers used, half fin with a full fin layer used. I learned a lot doing this for the first time and I still have a lot to learn, but I think it will turn out ok in the end. Filler to be applied and sanding to be done. Next up will be the electronics bay build, I just received my Fluctus order from Wildman this week and I now can procced with the build.

 

[Bobrogg]

Mocking up the electronics and Rouse-Tech CD3 component placement. I'll use two batteries, one for RRC2+ and one for the Fluctus system.