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Blue Tube Mega Vector Force

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ActingLikeAKid

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So it looks like my 38mm Minimum Diameter project is a bust. This means I get to build something else.... And I really think I'm going to go for this project I've had my eye on for a while: Upscaling the Vector Force with Blue Tube. OpenRocket says that pretty much the sky's the limit -- I should be flirting with a mile-high flight, I should be close to breaking the sound barrier; if I pass my L2 and can stuff a J in there, I can do both in one flight.

Before I jump in, does anyone see anything problematic with this? I may have posted this before, can't remember.

Here's a great thread with pictures of what the original Estes product looks like:
https://www.rocketryforum.com/showthread.php?25751-Estes-Vector-Force

I built one and utterly destroyed the finish (that's when I found out that enamel REALLY MEANS DON'T TOUCH FOR 48 HOURS) and got so frustrated I found a second one and bought it and built it. It's now one of my favorites - a perennially fun LPR bird that flies dead straight.

Here's what it ought to look like:
vectorforce.jpg

...and here's the OpenRocket for your consideration.
There are some details missing (like fillets and other minutae) but ... thoughts? If I have TTW fins, do I need to glass them as well, or is that overkill? I was thinking about making the transitions out of pine (maybe glassed?) or having a friend with a 3d printer knock them out. Would plastic or pine hold up to transonic/supersonic speeds?

Initially I had envisioned this as having a 29mm MMT, but I figure that I have more flexibility with a 38 -- I can always toss an adapter in there. So the original was 38mm (with 29mm mmt) to 29mm to 18mm for the upper body. Now it's 54 -> 38 -> 29, which means that a: I can build the whole thing out of Blue Tube and b: I ought to be able to find a nose cone pretty easily.

View attachment mega vector force54.rkt
 

MikeyDSlagle

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Awesome. I have an Estes Vector Force I have yet to build.

I would definitely go with the 38MMT. Aerotech motors are roughly the same price for 29mm and 38mm in the same impulse range. And CTI has a good offering of 'J's for the Pro38 case. Loki kas some 38mm 'K's, but it would probably be as long as your arm.

I have yet to fly anything bigger than a 'G' so all I have done is look at numbers and buy cases and it looks like 38mm is a good place to be. Longer burn times than 29mm but don't break the bank like 54mm.

I can't answer as to whether you should glass anything or not, haven't try for mach yet.

Mikey D
 

ActingLikeAKid

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Awesome. You'll enjoy the VF. I did mine in matte green with red transition, fins, and NC. Has a very "80's Soviet Missile" look to it.
 

BDB

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I think this sounds great. You shouldn't need to glass blue tube. I would think that the biggest issue with transsonic/supersonic speeds would be fin flutter. I'm guessing that the 0.152" plywood fins would need reinforcement. But this is new territory for me too. Time to figure out FinSim.
 

sl98

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I recently finished an upscale Vector Force with cardboard tube (BT70 to BT60 to BT 55) , 1/8 plywood fings & 29 mm MMT. Also set it up for dual deploy. Unfortunately , I haven't had a chance to fly it yet. I used a cardboard tube from an igniter to run the main charge through the balsa transition. Hopefully it flies as well as the LPR version.

ImageUploadedByRocketry Forum1476115882.436590.jpgImageUploadedByRocketry Forum1476115895.583026.jpg
 

ActingLikeAKid

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I recently finished an upscale Vector Force with cardboard tube (BT70 to BT60 to BT 55) , 1/8 plywood fings & 29 mm MMT. Also set it up for dual deploy. Unfortunately , I haven't had a chance to fly it yet. I used a cardboard tube from an igniter to run the main charge through the balsa transition. Hopefully it flies as well as the LPR version.

View attachment 303099View attachment 303100
Nice!! Good luck!
 

ActingLikeAKid

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OK, the build is officially on. I have a friend cutting the wings and putting together transitions for me; I just need to go shopping for Blue Tube. Trying to decide whether it's worth it to have them CNC the fin slots or if I should DIY with Dremel. My gut says to go with the former, pricey as it is -- it's one less thing to screw up, right?
 

Tonimus

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Why screw it up yourself when you can let someone else do it for you?
 

ActingLikeAKid

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OK, what am I forgetting? I've got the fins, transitions, and nosecone coming.

Ordering Blue Tube airframes, recovery harness, parachute, blanket, centering rings, motor retainer, and rail buttons. Am I forgetting anything?

I'm getting excited. This thing is going to look super cool.
 

MikeyDSlagle

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You mentioned airframes - how bout MMT.
Quick links
Rivets or screws if you intend to make it easy to disassemble.
You probably have those, but just covering some basics.
Extra 5' of 1/2" tubular kevlar...and send it to me. :D
 

ActingLikeAKid

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You mentioned airframes - how bout MMT.
Yup, some of the 29mm tube becomes MMT, some becomes airframe
Quick links
Always Ready doesn't sell them, think I can get them local.
Extra 5' of 1/2" tubular kevlar...and send it to me. :D
Heh. Actually I'm getting a nylon harness that I'm using as a shock cord, then I have some old Kevlar that I'm using to go down to the MMT.
Think it's time to pull the trigger on this!!!
 

ActingLikeAKid

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Let me try that again...
and no, I'm not making a 12-foot rocket (though wouldn't that be awesome?) I got the long sections of Blue Tube so I can use the remnants for other projects (also for "OH NO THAT'S NOT WHAT I MEANT TO" insurance). 3d printed NC and transitions. Going to get an aluminum rod to secure the first upper section, still deciding on what to do for the tip-top section. May glue it; may put some pins in so I can cram a GPS up there.
IMG_3514.jpg
 

Banzai88

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Cool. Are those solid or hollow prints?
 

ActingLikeAKid

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Cool. Are those solid or hollow prints?
Thanks!
Transitions are filled with a "honeycomb"-ish matrix. NC is hollow. Going to try to stuff an Eggfinder in the upper section, as high up as I can.
Same friend is going to fabricate a sort of "super eyebolt" for the lower-upper section - basically allthread with an eye on the end.
 

Banzai88

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Innovative, I like it. Did you print them yourself or use a service?
 

ActingLikeAKid

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Innovative, I like it. Did you print them yourself or use a service?
Thanks! I have a friend with a 3d printer who I think I owe a bottle of Scotch or something ;)

I'm really pleased with my idea for an upper-tube sled. Fancy stuff a-comin'.
 

ActingLikeAKid

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Question for anyone following: Is too much stability a bad thing? According to my initial forays, this thing will have stability of 4-5 cal with a motor in it. Obviously, that means it's prone to weathercocking in a good wind, but other than that, is a super-stable rocket a bad thing?
 

MikeyDSlagle

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Wow. That is stable! Other than the weathercocking your mentioned, I can't think of any reason too much stability is a bad thing. But most of mine are barely 1 Cal off the rail. I've read threads that talk about over stable rockets but can't remember the arguments. Soooo... as usual, I have not helped at all. LOL.

Saturday I hope to fly my Partizon with 3.33 Cal and my scratch built level 1 (finally) Danger Close with 2.64 Cal. Those are the most stable I will have launched to date. I will post reports, but I don't foresee any problems with overstable birds.

Mikey D
 

AdAstraPerAspera

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An overstable bird will weathercock badly if it is slow off the rail. Make sure you launch with a motor with a high initial thrust and you should be good.
 

ActingLikeAKid

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OK, cool. Thanks. Next question: As it's designed, I've got about 15 inches of 54mm BT between the top of the motor and the top of the BT (if I use the biggest J possible in this thing, and I'm hoping to eventually do L2 with it) Is that enough room for a 36" chute+15 feet of cord? I'm thinking I might need more room.
 

Crash-n-Burn

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OK, cool. Thanks. Next question: As it's designed, I've got about 15 inches of 54mm BT between the top of the motor and the top of the BT (if I use the biggest J possible in this thing, and I'm hoping to eventually do L2 with it) Is that enough room for a 36" chute+15 feet of cord? I'm thinking I might need more room.
You need to discount the length of the coupler as part of that available space but 15" is a lot to work with. I think you'll be fine.
 

ActingLikeAKid

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This is now a build thread. Slots from ARR were just a tiny bit short (as I'd wanted) so I dremeled out the lower slots & test fit the fins. Looking good. Ordered Cabot Sanding Sealer and it will be here in a week. Up next: Extending upper-fin slots, lots of test-fitting, grinding CRs to put the harness in them.

Anyone know if the "encapsulate the harness in epoxy" method is OK on BlueTube? I don't see why it wouldn't be, just wondered if anyone had tried it. Don't want to use a u-bolt or screw eye because there's precious little room between the MMT and the BT (mmt is 38mm, BT is 54)

btvf.jpg
 

ActingLikeAKid

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Current build list follows.
1. Sand holes to fit fins
2. Sand one end of 38mm tube to fit retainer
3. Take deep breath and cut BTs to length (38mm both for motor mount & lower-upper)
4. Sand ends of BTs nice & smooth
5. Cut CRs to let Kevlar fit through Cut 2 slots
6. Sand fins (45deg leading, 30deg trailing?)
7. Sand-seal all tubes (but only inside of mmt)
8. Bondo tubes
9. CA top CR in place
10. Test fit with top fins MARK MMT FOR ALIGNMENT. Adjust CR if necessary.
11. CA mid CR in place
12. Test fit with all fins Should be snug. Adjust CR if necessary.
13. retest fit with all fins
14. Score mmt all over. Put swivel on Kevlar, install Kevlar harness with swivel on it. Encapsulate with epoxy. Let cure. Whip top of Kevlar to make loop.
15. Retest fit with all fins
16. Epoxy CRs in place with good fillets on non-fin sides, "spot" fillets on fin-sides
17. Install mmt Test fins while curing.
18. Install lower fins with alignment jig. Double-butter for internal fillets.
19. Install upper fins One at a time, clamp w/straightedges
20. Install rear CR and motor retainer
21. Fillet upper & lower fins
22. Glass fins
23. Build Eggfinder tx
24. Build Eggfinder rx
25. Test Eggfinders
26. Install eggfinders and assemble upper-upper (pins to hold in place)
27. Assemble lower-upper
28. Primer
29. Sand, fill.
30. Primer
31. color coat
32. Contrast coat
33. Clear coat
34. Polish
35. Install recovery system
36. Fly!

Also just for grins & giggles, I upscaled this to see what would happen with a 75mm CTI M motor. 11k feet and Mach 1.5. That would be a fun L3, if someone dropped $1500 and ALL THE FREE TIME in my lap.
 

SDramstad

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Question for anyone following: Is too much stability a bad thing? According to my initial forays, this thing will have stability of 4-5 cal with a motor in it. Obviously, that means it's prone to weathercocking in a good wind, but other than that, is a super-stable rocket a bad thing?
Can you put a few canards up towards the top? That will bring the stability down a bit.
 
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