Bluefin Tuba 4"

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Parts showed up today. Rocketry Warehouse was kind enough to send me, along with a 60" airframe and nosecone, some offcuts they would normally throw away. One man's junk is another man's fincan.

Leah is full of excitement about this new project. Our plan is to fly it at TCC Dairy Aire two weeks from today. She helps me sort the parts, clean them and clamp them. We tack fin pairs with 30-minute epoxy, then make fillets out of RocketPoxy. First time using this stuff. These are the inside fillets. I hope the visible ones come out nicer.

Ari.

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You had me a "Tube Fin". Subscribed.

Looking forward to seeing this bird fly at Dairy Aire.

Every time I see Leah, she's grown another foot. Encourage her to play basketball or volleyball. There may be a full-ride scholarship at the other end.

BTW, nice color tubing from Rocketry Warehouse. It's definitely in keeping with the theme.
 
Well, it's a tube, and it's blue :=)

Ari.
 
Very nice, I can't wait to see this at DA. What motor are you looking at for the first flight?
 
Really interesting Ari, I hope to see it fly at TCC.

A question: will you be using some sort of physical attachment for the rings (like PEM nuts), or only adhesive?
 
Thank you for your encouragement guys. I'm thinking about a large L or a small M for TCC.
A question: will you be using some sort of physical attachment for the rings (like PEM nuts), or only adhesive?
I am yet to experience a flight failure that I can attribute to adhesive failure.

Ari.
 
This rocket, like its older siblings, can take a wide range of motors.

BFT 1.5" uses paper tape for motor retention. BFT 3" uses a screw-on AeroPack retainer. BFT 4" uses an AeroPack MD retainer. My measurements suggest that its upper lip must sit 10 3/4" from top of the fuselage. Luckily, Home Depot makes these disposable yardsticks that are exactly 10.75" long.

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While I have a stick that tells me how far to push the retainer, marking the tube to show where to put epoxy prove a bigger challenge. I use 3 pieces of masking tape 10.75" long to mark my distance.

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Epoxy is in place. I put epoxy in a relatively narrow ring. When I push the retainer in, it smears this ring as wide as I need it.

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Before pushing in the retainer, I remove masking tape. Tape reduces tube's ID enough that it's hard to push retainer in smoothly. Red object in foreground is a flashlight. Much easier to see inside the tube with it.

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All in, exactly 10.75"

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I dig this build so much--Leah looks like she's having a fantastic time!


Later!

--Coop
 
Thanks Coop!

Today I made and fitted an adapter for the casing I'm planning to fly at DA. Aeropack sells similar devices in anodized aluminum. I have a pretty long gap to cover, and it would require several of their extenders together to get to full length. I bought a piece of 3/8" all-thread, two coupling nuts and two set screws from Lowes and made an adapter that fits my casing exactly. My project suddenly turns into metal shop with cutting and drilling and tapping! I expect to make similar adapters for each casing I fly. They are cheap enough (about $6) that I can keep one for each motor without having to adjust them for a particular flight.

This is a 3" casing in the photo, so in addition to vertical adapter, you can see black 75-to-98 adapter rings on the casing.

Ari.

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Very nice! I'm currently building an " Ari special ". A 3" version of the Bluefin. It is dual deploy with a 54mm MMT. You have some great ideas!!! Keep up the good work.
 
Very nice! I'm currently building an " Ari special ". A 3" version of the Bluefin. It is dual deploy with a 54mm MMT. You have some great ideas!!! Keep up the good work.

I'm glad you're enjoying my threads. I try to keep my rockets simple, e.g. I avoid separate MMTs and associating centering rings; I simply make mine MD :=)

Ari.
 
Blue pigment for RocketPoxy arrived today (RW somehow neglected to include it with the rest or my order) and I laid external fillets. I like this color much better than black. It surprised me how much blue pigment I need to use--about 4 times as much as black, and the color is still a little pale.

In any case, I have fillets on all fin pairs now, and I have one of the pairs on the fuselage.

I mixed more epoxy than I needed to glue the pair of fins to fuselage, so I started on the AV bay. I'm trying an idea with a Kevlar strap instead of all-thread. I epoxied one side of the strap and tacked bock rings in place with the remaining epoxy in my pot. Color match appears better in the photo than in real life.

Ari.

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All the fins are on and I put on a fillet between two fin pairs. Three more fillets to go. I feel that I botched this one--I was trying to reflow it with a heat gun like RocketPoxy instructions tell you and overcooked it. Maybe I can cover it up with a cosmetic layer tomorrow.

AV bay is coming together nicely. Both ends of the strap are in. Need more complete fillets around the inside of the plywood rings.

Ari.

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Are you using launch lugs?Where would you install them if you do?
 
I use rail buttons. You can see where they go on the 1.5" and the 3" versions. Launch rail passes through one of the fins.

Ari.
 
Very nice build so far! I really like the color of the airframe! Looking forward to seeing more of this build!:)
 
Need to order some blue tube so will get 2 lots of these and a few other bits.

I've had a read but must of missed it.

How long are the tubes for the fins?

How far up from the bottom of the rocket are they?

The body is just one full length.

In thinking of only doing a 54mm MMT in a 3". I can use an Aeropack 3" to 54MM tail come then. I have Aeropack 54mm, 38mm and 29mm adapters. Flying L3 in the UK ain't cheap and only 1 place too really.

I would still build it super light like you, have Titebond II and the moulding trims.

I'm not sure if the Aeropack adapters would be putting it over weight and need nose weight then.
 
Pete, thank you for your kind words. Implementation is the most sincere form of flattery! I think you're asking about the 3" BFT. If you are, I encourage you to post in that thread. The short answer is that the numbers matter very little. I make my fins "a little longer than diameter." For 3" BFT, they are 3.75" long. For 4" BFT, they are 5" long.

Looking forward to your build thread!

Ari.
 
All the fins and fillets are on.

Leah and I put the stickers on today.

Ari.

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All dressed up and nowhere to go. DA launch rained out. While I'm figuring out where BFT4 might fly, I have to store it somewhere.

Ari.

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BFT4 flew and recovered today at TCC on AT L1520. Everything worked, including my glow-plug deployment initiation.

Ari.

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Photos of the first flight, one from Scott Yow via watermelonman and two from SCrocketfan.

Ari.

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