During initial construction I managed to JB-Weld the motor retainer backwards (even after double-checking). Discarded original 36" tube and replaced with 48" tube and 54mm threaded slimline retainer.
Initial rocket length: 83.5"
First flight (2014-09-13, I215) resulted in ~1.5" zipper on lower BT due to ascent separation. BT cut 1.5" shorter. Renamed "Bumbl-B mk II".
mk II rocket length: 82"
Second flight (first as mk II, 2014-09-13, I65W-P) resulted in ~1" zipper on upper BT and ~15" zipper on lower BT due to failed drogue charge (bad e-match). Cut upper BT 1.25" shorter and lower BT another 15" shorter. Renamed "Bumbl-B mk III".
Lower BT had to be cut below the original hardpoint anchor as zipper ran down to the hardpoint. Replaced with Aero Pack M54E retainer (drilling 5 holes for motor ejection bypass). Upper and lower BTs epoxied together at coupler (no longer separates). No longer capable of carrying electronics other than inside nose cone.
mk III rocket length: 65.75"
Thirteenth flight (tenth as mk III, 2015-03-21, I245G-12) resulted in 2.6" zipper on lower BT due to late AT motor eject. BT cut 2.6" shorter. Renamed "Bumbl-B mk IV".
mk IV rocket length: 63.125"
Fourteenth flight (first as mk IV, 2015-04-04, I357T-12) resulted in significant airframe damage due to very early AT motor eject. Lower BT zippered down to coupler from mkIII repair. Additionally the Slimline motor retainer was crimped during landing, had to be hacksawed off rocket. Rocket finally rebuilt March 2016, with two new airframe sections and new avionics bay coupler to replace damaged piece and restore original dual-deploy design. AeroPack M54E used to replace original Supermount during mk III repair now used for motor retention. Renamed "Bumbl-B mk V", used name "Return of Bumbl-B" on first flight card but name was not announced.
mk V rocket length: 82"
Fifteenth flight (first as mk V, 2016-04-02, I225FJ-P) resulted in ~18" zipper of lower BT due to failed apogee chute deployment (36" chute stuck in airframe). New BT section zippered entire length, down to coupler from mk III and mk V repairs. Rocket is awaiting rebuild once again (mk VI).
| Flight Date: | 2015-03-21 |
| Rocket Name: | Bumbl-B |
| Kit Name: | Giant Leap Rocketry - Firestorm-54 {Kit} |
| Flyer's Name: | Will Ferry |
| Motors: | I245-12 |
| Expected Altitude: | 2,657.00 Feet |
| Wind Speed: | 5.00 mph |
| Launch Site: | Tripoli Central California |
| Actual Altitude: | 2,638.00 Feet |
Successful ascent, motor ejection deployed parachute late. Chute ejection around 82 mph caused 2.5" zipper in airframe.
Flew with AltimeterThree and AltimeterTwo, zip tie holding altimeters to upper eye bolt broke at deployment, altimeters lost.
Flew with Eggtimer TRS @ 919MHz. Data recording stopped at 16.7s (ejection event), appears to be momentary power loss or reset of Eggtimer. Automatically rebooted to flight mode around landing time. Good visual on flight, but still used GPS coordinates to find in field.
Flew with Mobius ActionCam.
OpenRocket sim for flight suggested 11.4s optimal delay, with experience on all my AT delays being short I replaced the default -M (10s) delay with the -L (14s) delay (RDK-13PLUS), drilling -2s to achieve a 12s nominal delay. The actual ejection event occurred at T+16.2s, 14.8s after burn-out. Rocket estimated descent at around 120 ft/s at ejection caused zipper, loss of altimeters, and apparent power-cycle of Eggtimer TRS.
Final flight in the "mk III" configuration, airframe will be cut below zipper and rocket will return as "Bumbl-B mk IV".
| Stage | Motor(s) |
|---|---|
| 1 | I245G-12 |
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