Requesting Feedback on BT80 Angled Tri-Mount Rocket

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DemonicLacky

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Hey guys, I'm new to the forum.

I was hoping for some feedback on a project I've been working on for some time, but kind of need some incentive and feedback to complete.

I thought it would be fun to try working on something a bit different, so I've been putting together a BT80 Angled Tri-Mount rocket. If I finish it, I was going to dub it 'Cerberus' and either watch it CATO... or launch.

The engine shroud fillets were made with a few layers of drywall filler and primer. The primer used (the teal color) is spray putty from an automotive shop (Repco here in Australia). The bulkheads are all card stock purchased from Qualman Rocketry.

I was considering developing the upper fins to be servo controlled, but I've decided against it since It would take about a year of farting about to get anything working.

Currently I'm not super happy with the engine shrouds, as the engine retention rings I have make the bottom of the rocket super ugly. I was considering re-doing the entire thing to have the retention rings hidden away under the shrouds.

Anyway... What do you think?

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DemonicLacky

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Here's the installation of the bottom fins. They'll be glued to the engine shrouds on the inside of the main tube.

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DemonicLacky

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And here's the altimeter that's going to become the new base of the nose cone. It'll be kept in place with plastic screws.

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DemonicLacky

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Oh yeah... Here's the remote detonator I've put together to launch the thing. But don't worry, the detonator sends a coded message to a receiving unit that will be sitting outside the launch area with a cable running to the pad. The detonator isn't really needed, but was made for the 'fun' factor.

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mbeels

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Beautiful work! Looking forward to some launch reports. The "detonator" is quite impressive, very nice looking, did you design it yourself?
 

DemonicLacky

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Yep. All the bits were from AliExpress.com. It's an Arduino Nano with an NRF transmitter. If anyone wants a breakdown on how to build one I can put something up on the forum.
 

BABAR

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Nicely done.

With three engines in the tail it will be a bit tail heavy. Fins LOOK great, size may be a bit small for three motors, recommend simulate in open rocket or do an old fashioned swing test, it may nee some nose weight.

Make sure you have a 12 volt ignition system and clean clips. Wouldn't hurt to dip your starters in Fabritac glue or some other pyrogen dip.

I don't see motor hooks, so you are going for friction fit I assume. For "insurance " consider this.

Looks like you are done painting. Put a single "base" wrap of clear tape around the protruding segments of the motor mounts. This will protect them from peeling off paint and paper.

Friction fit you motors as usual. Add a wrap of tape (clear or masking, clear looks better) overlapping the protruding motor and the mount.

One more tip. Bring a zip lock bag to launch site. Remove the motors from the rocket soon after each launch (I find it easier to get friction fit motors out while they are warm, maybe it softens the tape?) Put the motors in the zip lock (if you have no appropriate trash receptacles on site) immediately , before you pack up your car. My experience has been if I leave motor in rocket and stick rocket in trunk the car is stinky by the time I get home.

Hope you get three straight trails. It's a pretty rocket!
 

mbeels

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My experience has been if I leave motor in rocket and stick rocket in trunk the car is stinky by the time I get home.
That's so true, and my wife is not a fan! (but my son loves "stinky rocket motor" smells)
 

neil_w

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With three engines in the tail it will be a bit tail heavy. Fins LOOK great, size may be a bit small for three motors, recommend simulate in open rocket or do an old fashioned swing test, it may nee some nose weight.
Came here to say the exact same thing.

Build looks great.

Sincerely,
Mind-simmer at large
 

lakeroadster

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Cool design! That fin can is aero awesome.

I swagged the design in Open Rocket... assuming D12 motors? Is the nose cone plastic or balsa? How long is the BT?

DemonicLacky Triple Cluster BT-80.jpg
 

DemonicLacky

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Oh wow. That's epic. Thanks.
  • The nose cone is plastic (liberated off an Estes V2).
  • The nose cone will be a bit heavier than the stock Estes V2, as I'm going to install an insert for the altimeter to go in.
  • The length of the tube is currently 46cm.
  • As per Babar's suggestion, I'm going to add a removable segment between the tube and the nosecone of 7cm to install 3 upper fins.
  • The upper fins might eventually be setup with servo's and a gyroscope to provide straight flight.
  • I've added the rocket's plans as a printable PDF to give you an idea of what I'm trying to achieve.

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