Bluefin Tuba 3"

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It's easy enough to replicate this rocket (that's the whole point of this design), but the replica won't have the neat flight log on its side.

Ari.

IMG_3475.jpg
 
[video=youtube_share;PID50SJbhIg]https://youtu.be/PID50SJbhIg[/video]

Pretty much the same angle as the previous video, but I'm a bit further away. I can send you the un-cut (and un-youtubbed) version if you want it.
 
Yup. Pretty much the same story :=(

Thanks for posting the video Robert.

Ari.
 
I guess it's oddly fitting that this thing successfully flies on G, H, I, J, K, L, and M motors and is then taken down by a D motor. Major bummer, but easy enough to build another one to do it all over again!
 
Dang!

Sadly, it looks like it's time to retire the BlueFinTuber 3.0 with full rocketry honors. BFT flew the entire range of motors from black powder to M-class...a serious and prodigious accomplishment.

I suggest hanging it from the ceiling of your rocketry workshop/area.

That being said, you can always build a new BFT 3.0 v2 and add any modifications that may have occurred to you over the original's flight history.


I'm looking forward to your next tube fin rocket, Ari.
 
It's a shame the smallest motor flown crashed this rocket . But think it will fly again
 
OhhhhNooooooo! I really do not think this will be a setback as much as a challenge to rebuild.

I have been thinking about this rocket popping Mach. My thoughts are that the size of the tubes themselves may be the reason it survived. The 3" tubes would be a lot less flexible than, say, 4".
 
Salvage-1 said:
OhhhhNooooooo! I really do not think this will be a setback as much as a challenge to rebuild.

I have been thinking about this rocket popping Mach. My thoughts are that the size of the tubes themselves may be the reason it survived. The 3" tubes would be a lot less flexible than, say, 4".
Click to expand...

I wonder what stress difference there is on airframe diameter . My thinking is bigger diameter the more area for stress load . But I see your point . The smaller airframe would load less due to the smaller area
 
You should post plans for the Bluefin Tuba --- that wide a motor range is really impressive. I want one.
 
chris m said:
I wonder what stress difference there is on airframe diameter . My thinking is bigger diameter the more area for stress load . But I see your point . The smaller airframe would load less due to the smaller area
Click to expand...

Yes, the smaller fins on Ari's Tuba would in theory, resist the compression stress a lot better than 4". On my 4" I will be inserting couplers into my fins to thicken and strengthen them. Hopefully, that will help. I also feel that it helped alot that Ari 'punched' through the Mach transition instead of coasting through it. With a 4" design, the weight is a little problematic. I am looking at around 25lb fully loaded. Ari's was a little lighter.

There is so much to be learned from Ari's flight. Trying to reproduce it with a 4" design would only be an extension of his accomplishments.
 
Thank you for your compliments Dan. As the man says, simplificate and add lightness. The very features that you are adding to increase strength are increasing your mass--to a point where you feel that your rocket is at a disadvantage. As for "punching" through Mach, BFT flew on the slowest-burning commercial M available. When the same motor ripped the fins off a Magnum in 2013, the consensus was that it took too long to transition through Mach :=)

Ari.
 
Yes I see where you coming from Dan . Hoping to be at mid west power and will see how a 4" does . But will not push it like ari did . I do have a 10" planned for my L3 . Should be fun
 
iter said:
Thank you for your compliments Dan. As the man says, simplificate and add lightness. The very features that you are adding to increase strength are increasing your mass--to a point where you feel that your rocket is at a disadvantage. As for "punching" through Mach, BFT flew on the slowest-burning commercial M available. When the same motor ripped the fins off a Magnum in 2013, the consensus was that it took too long to transition through Mach :=)

Ari.
Click to expand...

I was going to say...I looked at your data and the BFT3 spent a LOT of time in the transsonic regime.


Sent from my iPhone using Rocketry Forum
 
Ok, welp, I just ordered the parts for a Bluefin Tuba 54. That's an impulse range I'm likely to fly more often. Cost of airframe + NC, ~$60.
...and I just realized, five minutes after sending the money, that I have no plan for motor retention. Hmm, maybe time to brush up on lathe skills...
 
Zeroignite said:
Ok, welp, I just ordered the parts for a Bluefin Tuba 54. That's an impulse range I'm likely to fly more often. Cost of airframe + NC, ~$60.
...and I just realized, five minutes after sending the money, that I have no plan for motor retention. Hmm, maybe time to brush up on lathe skills...
Click to expand...

Are you planning on motor ejection or electronics? Are you planning on adapting down?

I used an Aeropack retainer on BFT 3" and paper tape on BFT 1.5". Especially with electronic deployment and plugged (tapped) closers, I'd feel very confident using tape even on 3" version, and certainly on 2". With motor acting as recovery attachment point, the worst that can happen is rear ejection.

Another thought I entertained and rejected was gluing the fins to extend 1/2" or 3/8" below the fuselage. I would drill each fin in the side that faces the motor, put a t-nut or a clip nut in, and use 6 machine screws (one through each fin, pointing toward the nozzle) to hold the motor. Upside is cheap and lower drag than Aeropack. Downside is undoing 6 screws between flights.

Ari.
 
iter said:
Another thought I entertained and rejected was gluing the fins to extend 1/2" or 3/8" below the fuselage. I would drill each fin in the side that faces the motor, put a t-nut or a clip nut in, and use 6 machine screws (one through each fin, pointing toward the nozzle) to hold the motor. Upside is cheap and lower drag than Aeropack. Downside is undoing 6 screws between flights.

Ari.
Click to expand...

You wouldn't need six... two would do it fine.
 
iter said:
Are you planning on motor ejection or electronics? Are you planning on adapting down?

I used an Aeropack retainer on BFT 3" and paper tape on BFT 1.5". Especially with electronic deployment and plugged (tapped) closers, I'd feel very confident using tape even on 3" version, and certainly on 2". With motor acting as recovery attachment point, the worst that can happen is rear ejection.

Another thought I entertained and rejected was gluing the fins to extend 1/2" or 3/8" below the fuselage. I would drill each fin in the side that faces the motor, put a t-nut or a clip nut in, and use 6 machine screws (one through each fin, pointing toward the nozzle) to hold the motor. Upside is cheap and lower drag than Aeropack. Downside is undoing 6 screws between flights.

Ari.
Click to expand...
Motor eject, altimeter single-event, or head-end DD depending on the flight and the motor. Yeah, in practice I'll probably friction + tape, or do the circumferential screws. If the latter, I'd definitely only use two. Oh, and definitely adapt down using matroshka'd MMTs.

Edit: sweet Jebidiah, this is simming happily on everything from a D24 to a J500. That's just silly.
 
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I"m pondering a BFT 3" of my own and a have a few questions.

1. In your original BFT 38mm thread you started with a standard 48" long Blue Tube and cut the 2" long tube fins from that. How long did make the fuselage and the tubefins. How long is the body tube on the 3" version? I'm thinking to order two length of BT.

Never mind...I found the description. 48" long just as it came from the factory...and two tubes required.

2. Looks like the BFT 3" is a single length airframe without a mid body alt bay. Did you use a Cable Cutter set up and altimeter in the NC?
 
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o1d_dude said:
I"m pondering a BFT 3" of my own and a have a few questions.

1. In your original BFT 38mm thread you started with a standard 48" long Blue Tube and cut the 2" long tube fins from that. How long did make the fuselage and the tubefins. How long is the body tube on the 3" version? I'm thinking to order two length of BT.

Never mind...I found the description. 48" long just as it came from the factory...and two tubes required.
Click to expand...

Right. BFT 1.5" requires one 48" tube. I cut off 6, 2" fins and (taking into account 1/8" kerf) end up with 35 1/4" fuselage. I have no leftovers from this build.

BFT 3" requires two tubes, and I still have part of the second tube.

2. Looks like the BFT 3" is a single length airframe without a mid body alt bay. Did you use a Cable Cutter set up and altimeter in the NC?
Click to expand...

Yes. The altimeter is in the nose cone (this setup: https://www.rocketryforum.com/showthread.php?67266-Nose-Cone-A-V-Bay). I tried Archetype cable cutters; I also made my own from an R/C engine glow plug--this setup melts a rubber band that holds the parachute bungle from unfurling and is a lot cleaner--no powder residue etc. In the desert, I flew the rocket single deploy. The wind was so calm, and the visibility so clear, I decided that I'm testing the airframe, not my experimental cable cutter. So would you believe it, I flew to almost 15,000' with intentional main deployment at apogee.

Ari.
 
Thanks for the information and the link.

It was difficult to tell for sure from the Black Rock pictures but I was pretty sure you had the alt bay in the nose cone. Somehow I'd forgotten about your nosecone alt bay thread.

15K with not dual deploy? You usually do things unconventionally so I would believe it. LOL!

Thanks!
 
o1d_dude said:
15K with not dual deploy? You usually do things unconventionally so I would believe it. LOL!
Click to expand...

That's the honest truth. You can see it in the altimeter logs a couple of pages back.

Ari.
 
It's pretty common to pop your main parachute at apogee at Black Rock. The Honey Badger project did the same thing from 63,000' as it reduces volume required within the rocket.

I'll be deploying my main at apogee on the out here in the East at LDRS when I try for 20k and mach 2. This results in a much smaller volume for recovery in my design.
 
I'd like to have a go at building one.

So 2x 3" tubes needed. What length are the tubes for the fins?

Am thinking of making it with removable motor mounts also.

Did you use Titebond on this one for the fins also or epoxy.

Sorry for all the questions.

Pete.
 
This build is all yellow glue. This is one of the points this build aims to drive home, that you can do it with yellow glue alone.

Fin length is less important. I make them slightly longer than diameter, mostly for mechanical rigidity considerations.

Ari.
 
iter said:
This build is all yellow glue. This is one of the points this build aims to drive home, that you can do it with yellow glue alone.

Fin length is less important. I make them slightly longer than diameter, mostly for mechanical rigidity considerations.

Ari.
Click to expand...

Thanks Ari for getting back too me.

Where did you mount the electronics
 

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