Bumblebee XL - Build Thread

[RAHagen]

So as i'm finishing up my Torrent for my Jr. lv. cert, I'm starting to think about what my next project should be, and my mind came back to a two stage rocket I made about a year ago. *...cue flashback...* It was just a rocket I designed and built with spare parts around the house in a couple days because I had parts to use up. It ended up being a minimum diameter, two stage rocket that was around 15 inches tall and ran on two E motors.



With those motors, the rocket was simulated to go upwards of 4400 ft, so I was pretty sure it was gonna disappear the first time I launched it. When the day finally came, It flew into the glare of the sun and was never seen again. We did, however, find the booster stage impaled in the ground with nice core sample of the Oklahoma soil. The booster now has a permanent spot on a shelf in my room.

[video=youtube_share;2ACdcMHZ0Kw]https://youtu.be/2ACdcMHZ0Kw[/video]

Back story aside, I was thinking that a good next project would be up-scaling this rocket to 29mm and increasing the motor size to one of the Estes 29mm black powder motors like the F15. I could also, sometime later, build a second, slightly longer, booster stage with room for staging electronics for composite motors and be able to use black powder and composite motors interchangeably in the rocket. With the body being 29mm It has enough room to fit my Telemetrum GPS telemetry system inside it so the chance of losing the rocket would be greatly reduced.
What do you guys think? A worthy design?

Rocksim file: View attachment Bumblebee.ork.rkt

 

[codysmith]

I like!!! Make sure to do a build thread!

 

[RAHagen]

I like!!! Make sure to do a build thread!

Thanks! I plan to make use this thread as the build thread. I'm really excited about this rocket. If it works it will fly higher than any other rocket I have ever made. And that includes some G motors! And if I do plan to upgrade it to work with composite motors, if I run it on G motors it's simmed to go around 7000 feet and get to a speed of mach 1.15! Under those stresses though I think the materials I plan on using would fail so I might not end up doing that.

Tonight I got the body tubes cut to size. The sustained body in rocksim is supposed to be 12 inches, but I lengthened it to 13 to keep from cutting the factory edge for a 1 inch cut.

I might not be able to update this thread as much as I'd like with school coming up really quick, my Jr. Lv. 1 certification next Saturday, and the rest of stuff that goes on when school is in session. I'll try to update it as much as I can.

 

[RAHagen]

Well, I finally got around to working on this rocket again! School kinda stopped me dead in my tracks when it came to working on rockets. Since my last post, I was able to cut, sand, and airfoil the fins for both stages.



All in all, it's a fairly simple build. Next up is to glue and fillet the fins to the first and second stages.

 

[RAHagen]

I was able to get the fins attached to the stages.



I've been thinking that the body might be too weak. Do you guys think that fiber-glassing the fins tip to tip would add too much weight to the rocket?

 

[RAHagen]

So since the last time I updated the thread I've filleted the booster and sustainer and filled the spirals in the sustainer with Bondo spot putty.

 

[RAHagen]

Well I thought I might update this thread since I plan on launching this rocket on the thirteenth. Since my last update, I have painted the rocket, turned the nose cone from balsa and finished attaching the recovery system. For the streamer, I'm using a 12" nomex parachute protector. The rocket is so light and the airframe is so small that a fast decent might be necessary to find this rocket. The paint job is an attempt to make this rocket as visible as possible. I haven't have enough successful launches with my telemetrum transmitting telemetry to trust it in a small high-altitude rocket so hopefully I'll be able to find this rocket afterwards...

 

[boomtube-mk2]

Back story aside, I was thinking that a good next project would be up-scaling this rocket to 29mm and increasing the motor size to one of the Estes 29mm black powder motors like the F15. I could also, sometime later, build a second, slightly longer, booster stage with room for staging electronics for composite motors and be able to use black powder and composite motors interchangeably in the rocket. With the body being 29mm It has enough room to fit my Telemetrum GPS telemetry system inside it so the chance of losing the rocket would be greatly reduced.
What do you guys think? A worthy design

I flew a two stage 29mm BP powered rocket at AirFest this past September.

The sustainer airframe was bt 70; why? Because I had one, along with an unused plastic nosecone for it.
It tail-cone’s down to a bt 60 for the booster which intern has its own tail-cone.

It is all lightweight materials yet using the F15-0 the rocket had a nice slow takeoff with staging occurring lower than most of my D12-0 or even C6-0 two stagers.

I think that “15” rating might be a bit optimistic.

 

[RAHagen]

I flew a two stage 29mm BP powered rocket at AirFest this past September.

The sustainer airframe was bt 70; why? Because I had one, along with an unused plastic nosecone for it.
It tail-cone’s down to a bt 60 for the booster which intern has its own tail-cone.

It is all lightweight materials yet using the F15-0 the rocket had a nice slow takeoff with staging occurring lower than most of my D12-0 or even C6-0 two stagers.

I think that “15” rating might be a bit optimistic.

Yeah I've heard that the F15's have a pretty low starting impulse. I'm actually planning to fly it on the new 29mm E's instead because with the F15's it would break the 5000 foot waiver at my local club.