[RocketsNW] Alphabet Ladder Project Summary

[Bob and Ann Yanecek]

After successfully flying my Dual-75 rocket on a 7%M-1200 last year at
BALLS I came upon the idea of flying the Alphabet from A through
M-impulse over the course of the 2008 season.
Several folks invented their own Alphabet Ladder Projects this year.
Mark Lyons: ‘Monkey Style’ (no particular order).
Ray Stoner: Each rung flown in a different airframe where total impulse
defined the rungs thus allowing clusters.
Marty Weiser: Alpha’s only.
 
My personal goal was to fly sequentially through the Alphabet in minimum
diameter fiberglass airframes.
 
My quest began in March at the Blue Mountain Rocketeers (HYPERLINK
"http://www.bmr615.org/"http://www.bmr615.org/) ‘Spring Fling’ launch.
I decided to go with an 18mm airframe for A-C impulse and quickly
learned(remembered) how small 18mm is when packing a parachute.
With a pad weight of 89 grams the A8-3 motor pushed the rocket to a
simulated 90’ yet still managed to get the chute out and open before
touchdown.
I selected a B6-4 next.  After several igniter issues, I finally got the
motor lit and the rocket boosted to a simulated 309’.
The final push for the 18mm airframe was via C6-7 resulting in a good
flight to a simulated altitude of 878’ putting me up to a total of
1,277’ for the first 3 rungs of my project.
 
I next pulled out my 24mm rocket and loaded up a D12-7.  
The pad weight of 147 grams was a tad heavy (should have used the 5 sec
delay) resulting in a late high speed deployment of the parachute and
tangled recovery.  
As I walked out to recover the rocket I stumbled across the motor which
had spit out and disqualified the attempt.  
I reloaded another D12-7 (no 5 sec delays in my range box) and succeeded
with a good boost and successful high speed deployment.
 
I had to wait 3 weeks before attempting the E-rung at SPARC’s April
launch (HYPERLINK
"http://sparc.rocketclub.org/"http://sparc.rocketclub.org/).
I loaded up an E9-8 and opted to stick with a parachute instead of a
streamer.  
The rocket managed to hang itself in a tree which took all day to
retrieve thus eliminating my plans of additional rungs that day.
 
Another 3 weeks passed before I could attempt the F-rung at WAC’s
Mansfield launch (HYPERLINK
"http://www.washingtonaerospace.org/"http://www.washingtonaerospace.org/
) in early May.
This represented my first reloadable motor (F12-5) and the 5 second
delay was woefully short for the 173 gram rocket (pad weight).  
Deployment occurred at high speed but the chute hung together and
recovery was nominal.
This concluded my 24mm efforts and had me up to a simulated 7,401’ on my
ladder.
 
Next up was 29mm where I had planned to incorporate an avionics bay and
electronic deployment along with measured vs simulated altitude.
I had two different 29mm airframes with MAWD’s located just behind the
N/C and relying on dual deployment with just one break of the airframe
at the fin can/BT joint.  
Theory was that the apogee charge would separate the airframe but not
pull out the main which was supposed to get pushed out when the main
charge fired.
In addition to electronics I also included a Walston tracking
transmitter.  
Multiple design flaws quickly had me regretting the fact that I built
two of these 29mm airframes.
With the avionics bay just behind the N/C, the rocket was way over
stable.  
Couple that with the Walston sitting beside the 9VDC battery which
caused a significant radial offset CG and the rocket experienced extreme
coning during ascent.  
Everything held together, the main stayed in at apogee and was ejected
when the main charge fired as designed, however the nylon chute also
melted closed resulting in a high speed landing (79 ft/sec) which broke
the airframe just behind the avionics bay thus disqualifying the
attempt.  
Luckily, I had my motor eject GTV along with me which I loaded up with a
G25-10 resulting in a good flight with nominal recovery.
Since I already had a second (poorly designed) 29mm rocket with avionics
behind the N/C, I decided to go ahead and attempt the H-rung via H-180. 
Again, boost was extremely squirrelly but the chute stayed in at apogee
and again the chute melted closed when the main charge pushed it out.  
Luckily the rocket landed soft (still fast at 103 ft/sec) and undamaged
so I decided to count the rung.  
Total flight time was 72 seconds.  
Future versions of the 29mm airframe will move the avionics bay back to
just in front of the motor in an effort to bring the CG back closer to
the CP and eliminate the coning problem.
 
Fire In the Sky (FITS) found me back at Mansfield to continue climbing
my ladder.  
I was now up to 17,895’ and flying 38mm airframes.
I selected an I-284 for the I-rung resulting in a clean boost.  
The rocket was dual deploy going drogue-less at apogee then a 36”
parachute for main deployment.
Apogee was at 21 seconds into the flight and then at 91 seconds the main
wiggled out.  
Total flight time was 317 seconds and post flight inspection revealed
signs that the fin can had impacted the upper airframe which I suspect
knocked the main parachute out.
 
The J-rung provided me my first opportunity to fly a research motor so I
went with a DAWG pack MAL 4%J356 resulting in a good flight to 8,650’.
 
While I had a 54mm rocket under construction, it wasn’t ready to fly by
the next launch opportunity (June Mansfield launch) so I opted to go
straight to 75mm and an AMW K365 push.
The flight was nominal to 9,202’ and 248 seconds time of flight.  
Descent under drogue was 58 ft/sec and a comfortable 17 ft/sec under
main.
 
Six weeks later and I was back at Mansfield to attempt the L-rung of my
project.  
For this flight I selected a DAWG pack 3G75 MAL 66%L905.  
Due to an errant piece of duct tape on my tower which managed to catch
the aft thrust ring, the rocket kicked as it exited the tower resulting
in a fair downrange trajectory.  
Recovery was nominal though post flight inspection revealed the motor
case had burned through between the first two grains of the motor. 
Fortunately the burn through occurred late enough that there was just a
small black burn mark on the inside of the fin can extension.  
A very close call resulting in a decision to open up the nozzle a tad in
an effort to reduce internal pressure/temp for future motors in this
configuration.
 
Late September found me back at Black Rock and AHPRA’s annual BALLS
launch (HYPERLINK "http://www.balls17.com/"http://www.balls17.com/).
Since I had succeeding with a 4G75 6%M1200 last year, I decided to skip
the 5 grain configuration and jump to a DAWG pack 6G75 MAL 50%M1950.
The rocket weighed 22 lbs 6.0 oz in the tower and while the motor
performed nominally, the rocket was not up to that kind of push.  
A little over 2 seconds into the boost the fins began to flutter
followed immediately by airframe destruction (it looked as if the rocket
hit a wall).  
Post flight inspection revealed all 3 fins stripped and the airframe
buckled just behind the avionics bay.  
The N/C, avionics bay, fin can extension, and motor hardware were
recovered undamaged.  
The same cannot be said for my ego :-(.
I’m now studying fin design/construction techniques with plans to
re-attempt the M-rung next year.
 
All in all this was a great project that kept me busy and engaged at all
levels of the hobby .
I managed to tally a total of 63,292’ up through the L-rung of my
project, learned a lot and had tons of fun.
Fun is GOOD!
 
Bob Yanecek
 
 

No virus found in this outgoing message.
Checked by AVG. 
Version: 7.5.524 / Virus Database: 270.7.5/1705 - Release Date:
10/3/2008 8:18 AM
 
-------------- next part --------------
After successfully flying my Dual-75 rocket on a 7%M-1200 last year at BALLS I came upon the idea of flying the Alphabet from
A
through M-impulse over the course of the 2008 season.
Several folks invented their own Alphabet Ladder Projects this year.
Mark Lyons: ‘Monkey Style’ (no particular order).
Ray Stoner: Each rung flown in a different airframe where total impulse defined the rungs thus allowing clusters.
Marty Weiser
: Alpha’s only.
 
My personal goal was to fly sequentially through the Alphabet in minimum diameter fiberglass airframes.
 
My quest began in March at the Blue Mountain Rocketeers ( http://www.bmr615.org/ http://www.bmr615.org/
) ‘Spring Fling’ launch.
I decided to go with an 18mm airframe for A-C impulse and quickly
learned(
remembered) how small 18mm is when packing a parachute.
With a pad weight of 89 grams the A8-3 motor pushed the rocket to a simulated 90’ yet still managed to get the chute out and open before touchdown.
I selected a B6-4 next.
 
After several igniter issues, I finally got the motor lit and the rocket boosted to a simulated 309’.
The final push for the 18mm airframe was via C6-7 resulting in a good flight to a simulated altitude of 878’ putting me up to a total of 1,277’ for the first 3 rungs of my project.
 
I next pulled out my 24mm rocket and loaded up a D12-7.
 
The pad weight of 147 grams was a tad heavy (should have used the 5 sec delay) resulting in a late high speed deployment of the parachute and tangled recovery.
 
As I walked out to recover the rocket I stumbled across the motor which had spit out and disqualified the attempt.
 
I reloaded another D12-7 (no 5 sec delays in my range box) and succeeded with a good boost and successful high speed deployment.
 
I had to wait 3 weeks before attempting the E-rung at
SPARC’s
April launch ( http://sparc.rocketclub.org/ http://sparc.rocketclub.org/
).
I loaded up an E9-8 and opted to stick with a parachute instead of a streamer.
 
The rocket managed to hang itself in a tree which took all day to retrieve thus eliminating my plans of additional rungs that day.
 
Another 3 weeks passed before I could attempt the F-rung at
WAC’s
Mansfield
launch ( http://www.washingtonaerospace.org/ http://www.washingtonaerospace.org/
) in early May.
This represented my first
reloadable
motor (F12-5) and the 5 second delay was woefully short for the 173 gram rocket (pad weight).
 
Deployment occurred at high speed but the chute hung together and recovery was nominal.
This concluded my 24mm efforts and had me up to a simulated 7,401’ on my ladder.
 
Next up was 29mm where I had planned to incorporate an avionics bay and electronic deployment along with measured
vs
simulated altitude.
I had two different 29mm airframes with
MAWD’s
located just behind the N/C and relying on dual deployment with just one break of the airframe at the fin can/BT joint.
 
Theory was that the apogee charge would separate the airframe but not pull out the main which was supposed to get pushed out when the main charge fired.
In addition to electronics I also included a Walston tracking transmitter.
 
Multiple design flaws quickly had me regretting the fact that I built two of these 29mm airframes.
With the avionics bay just behind the N/C, the rocket was way over stable.
 
Couple that with the Walston sitting beside the 9VDC battery which caused a significant radial offset CG and the rocket experienced extreme coning during ascent.
 
Everything held together, the main stayed in at apogee and was ejected when the main charge fired as designed, however the nylon chute also melted closed resulting in a high speed landing (79 ft/sec) which broke the airframe just behind the avionics bay thus disqualifying the attempt.
 
Luckily, I had my motor eject GTV along with me which I loaded up with a G25-10 resulting in a good flight with nominal recovery.
Since I already had a second (poorly designed) 29mm rocket with avionics behind the N/C, I decided to go ahead and attempt the H-rung via H-180.
Again, boost was extremely squirrelly but the chute stayed in at apogee and again the chute melted closed when the main charge pushed it out.
 
Luckily the rocket landed soft (still fast at 103 ft/sec) and undamaged so I decided to count the rung.
 
Total flight time was 72 seconds.
 
Future versions of the 29mm airframe will move the avionics bay back to just in front of the motor in an effort to bring the CG back closer to the CP and eliminate the coning problem.
 
Fire
In
the Sky (FITS) found me back at
Mansfield
to continue climbing my ladder.
 
I was now up to 17,895’ and flying 38mm airframes.
I selected an I-284 for the I-rung resulting in a clean boost.
 
The rocket was dual deploy going drogue-less at apogee then a 36” parachute for main deployment.
Apogee was at 21 seconds into the flight and then at 91 seconds the main wiggled out.
 
Total flight time was 317 seconds and post flight inspection revealed signs that the fin can had impacted the upper airframe which I suspect knocked the main parachute out.
 
The J-rung provided me my first opportunity to fly a research motor so I went with a DAWG pack MAL 4%J356 resulting in a good flight to 8,650’.
 
While I had a 54mm rocket under construction, it wasn’t ready to fly by the next launch opportunity (June Mansfield launch) so I opted to go straight to 75mm and an AMW K365 push.
The flight was nominal to 9,202’ and 248 seconds time of flight.
 
Descent under drogue was 58 ft/sec and a comfortable 17 ft/sec under main.
 
Six weeks later and I was back at
Mansfield
to attempt the L-rung of my project.
 
For this flight I selected a DAWG pack 3G75 MAL 66%L905.
 
Due to an errant piece of duct tape on my tower which managed to catch the aft thrust ring, the rocket kicked as it exited the tower resulting in a fair downrange trajectory.
 
Recovery was nominal though post flight inspection revealed the motor case had burned through between the first two grains of the motor.
Fortunately the burn through occurred late enough that there was just a small black burn mark on the inside of the fin can extension.
 
A very close call resulting in a decision to open up the nozzle a tad in an effort to reduce internal pressure/temp for future motors in this configuration.
 
Late September found me back at Black Rock and
AHPRA’s
annual BALLS launch ( http://www.balls17.com/ http://www.balls17.com/
).
Since I had succeeding with a 4G75 6%M1200 last year, I decided to skip the 5 grain configuration and jump to a DAWG pack 6G75 MAL 50%M1950.
 
The rocket weighed 22 lbs 6.0 oz in the tower and while the motor performed nominally, the rocket was not up to that kind of push.
 
A little over 2 seconds into the boost the fins began to flutter followed immediately by airframe destruction (it looked as if the rocket hit a wall).
 
Post flight inspection revealed all 3 fins stripped and the airframe buckled just behind the avionics bay.
 
The N/C, avionics bay, fin can extension, and motor hardware were recovered undamaged.
 
The same cannot be said for my
ego
L
.
I’m now studying fin design/construction techniques with plans to re-attempt the M-rung next year.
 
All in all this was a great project that kept me busy and engaged at all levels of the
hobby .
I managed to tally a total of 63,292’ up through the L-rung of my project, learned a lot and had tons of fun.
Fun is GOOD!
 
Bob Yanecek
 
 
No virus found in this outgoing message.
Checked by AVG.
Version: 7.5.524 / Virus Database: 270.7.5/1705 - Release Date: 10/3/2008 8:18 AM