Another 3" Minimum Diameter Build. Rockets name: "BoomStick"

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Just got Boomstick back from the paint shop. The color is Wicked Red.

59E050E8-324D-4E07-96F2-19B5A2371603.jpg

Very nice build. Good luck on the flight
 
I've been following your thread very much in very impressed 'watch and learn' mode. A dumb noob question, if I may... Given the layers of CF, how have you avoided any differentiation in diameter between the nose cone and the airframe? Is the NC covered with CF as well?
 
I've been following your thread very much in very impressed 'watch and learn' mode. A dumb noob question, if I may... Given the layers of CF, how have you avoided any differentiation in diameter between the nose cone and the airframe? Is the NC covered with CF as well?

There is a tapered layer of Bondo on the nose cone about two inches from the shoulder up. Makes for a perfect fit. I learned that from Jim Jarvis.
 
for those of us not at a launch today

[video=youtube;PR1BHmKm5Hw]https://www.youtube.com/watch?v=PR1BHmKm5Hw[/video]
 
Here is the 4k res. video of the flight. Be sure to click the gear and set your resolution to 4k if you have the bandwidth.

[YOUTUBE]NcbbB67NEZ0[/YOUTUBE]
 
Nice pics, the flight looked great! I'll have to view the video when I get home, as I am blocked at work. That flame is longer then the rocket!
 
Flight Recap:

Ignition and boost phase were nominal although a bit under powered. I'm definitely going to up the KN in the motor by making it a 6 grain.
Apogee event was on time but something happen to both the main ematches. Both were detached from the connection at the base of the nose.
Also the cable tie had been broke off from around the chute either at apogee or sometime on the way down. Even though the chute was
free to deploy. It did not and stayed tangled between the shock cord, nosecone, and chute protector. So everything tumbled in from apogee.
the result was the airframe breaking in two just above the motor case and the tip breaking off the nosecone.

IMG_7347.jpg
IMG_7346.jpg
 
looking at the rail? in pic 1 vs pic 2 you got some serious whip - what kind of pad were you launching from?
 
The Data:

I had a Raven II flight controller on board. So here is my attempt at data analysis.

Summary Data:

Average PreLaunch Altitude (ft) = Val: 1191.00
Average PreLaunch Axial (Gs) = Val: 1.17
Average PreLaunch Axial Offset = Val: 1.17
Axial Accel (Gs) = Min: -2.72 Max: 74.86
Baro (Atm) = Min: 0.4940 Max: 0.9577
Current Draw (A) = Min: 0.06 Max: 0.13
Flight Count = Val: 7.00
Lateral Accel (Gs) = Min: -2.72 Max: 1.31
Motor Ignition Time (sec) = Val: 0.165
Temperature (F) = Min: 102.28 Max: 103.08
Time (sec) = Min: 0.000 Max: 34.280
Velocity (Accel-Ft/Sec) = Min: 0 Max: 1365
Volts Battery (V) = Min: 7.56 Max: 7.60
Volts Pyro 3rd (V) = Min: 0.00 Max: 0.00
Volts Pyro 4th (V) = Min: 0.00 Max: 0.00
Volts Pyro Apogee (V) = Min: 0.00 Max: 7.60
Volts Pyro Main (V) = Min: 7.56 Max: 7.60
[Altitude (Accel-Ft)] = Min: 0 Max: 19017
[Altitude (Baro-Ft-AGL)] = Min: 0 Max: 17071
[Altitude (Baro-Ft-ASL)] = Min: 1191 Max: 18262
[Velocity (Accel-Ft/Sec)] = Min: -106 Max: 1348
[Velocity (Accel-MPH)] = Min: -72 Max: 919

First let's look at the motor burn. The burn starts with a 12 G spike at ignition .165 seconds and drops back to 10 G's at about 1 second. Then gets progressive back up to 12 G's at the 3 second mark. then the pressure starts a steady regression till burn out at about 5.5 seconds.From my testing with smaller motors this propellent needs a KN of about 300. I was running the larger one at a max of 280 just to be on the safe side. So once the KN dropped this explains the regressive burn as the pressure dropped below optimal.

Burn1.jpg
 
Apogee:

This is when things start to go wrong. From what I can tell the rocket was still traveling at 80mph when the apogee charge blew. This is evident by the huge spike of 75 G's as the 20' of shock cord snapped tight. I suspect this is when the main charge e-matches in the cable cutters got torn loose and the cable tie actually broke from the force. You can see the main voltages drop to zero indicating a open circuit. All the electronics were in the nose along with 1.5lbs of nose weight. So I suspect there was a good bit of momentum developed to cause all of the carnage. Fortunately for me the Eggfinder GPS was functioning perfectly and the rocket was reporting position and altitude back to the ground station.

Apogee1.jpg
 
looking at the rail? in pic 1 vs pic 2 you got some serious whip - what kind of pad were you launching from?

One of the 70's pads at Argonia. Standard Kloudbusters pad. Looks like a welded rebar tripod. 1010 rail. It was a long one. 10'.

I think I weather cocked into the wind too. It was blowing 10 - 12mph. It was a 4 rocket drag race. Only 2 left the pad. Mine and Chris Short's
Both 3" rockets with 75/6000 motors. He had a main at apogee and he landed 2 miles in the opposite direction as mine. In the video you can
see his rocket launch after mine.
 
Recovery:

The Eggfinder was working perfectly up until it hit the ground then nothing. It had the last coordinates on the display so I entered them into the MotionX app on my iPhone and it showed it was in a field a mile South of the launch pad. So I drove over and walked out into the field and sure enough the rocket was right where it said it was. But as I got closer I could see all the damage to the airframe and nose cone. After further examination I found the GPS chip had busted off the circuit board of the Eggfinder. So the next one I build I'll put a piece of clear heat shrink tubing over the GPS chip. From the accelerometer data it appears that it hit pretty hard. There is a 43 G lateral spike and an 80G (MAX G's) longitudinal spike at impact. Enough to bust up my G10 sled that I had build in the nosecone and of course destroy my Eggfinder GPS. It also bounced once as you can see in the graph below.

Impact1.jpg


This concludes my post flight analysis until next years AirFest project. :cool:
 
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