Flight Log for 26 August 200, 60 Acres Park, Redmond, WA

Overcast appr. 2000' AGL, very light rain sprinkles intermittently, wind 5-7 N tapering to 0-3 variable.
Model Flt 
#
Recovery Type Motor Comments
Cherokee-D (2)
22
12" plastic parasheet w/ spill and vents
Quest C6-5 I didn't have any D12-7 motors left -- and might not see them again, though a recent discussion of kits Estes is bringing back gives some hope they might produce more in the future.  In the meantime, I decided to fly the Cherokee on an 18 mm motor.  Everything about the flight was nominal, except that I didn't have enough rod angle and the rocket drifted back behind the launcher, crossed the line of blackberry brambles at the edge of the field, and landed just beyond the road in the next lot.  No damage, and no problem recovering.
Cherokee-D (2)
23
12" plastic parasheet w/ spill and vents
Aerotech RMS 24/40 D15-7T
I wanted to fly the Cherokee on a D motor, but after stripping the parachute on a D12-5 I wasn't going to try that again.  The solution was found in the same pack of D15-7 reloads I'd used at Monroe for the BBBertha's first flight at that launch.  I loaded up the motor, put the rocket on the pad, and with the Copperhead that came in the motor pack got immediate ignition and the rocket launched with authority.  For whatever reason, it turned a bit just off the rod (I'm thinking rod whip; this is a lot of motor for a 1/8" brass launch rod) and went well upwind, but returned on the field after a little drift.  Recover, clean the reload, and done.
Astron Cobra
10
12" plastic parasheet
3x Estes B6-6
I didn't want to spend the time to build another reload -- though the E18 tempted me, I also didn't want to risk losing the case by recovering off the field.  Instead, I decided to see what I had for the Cobra, and found a fresh pack of B6-6 motors from my last trip to the hobby shop.  I quickly prepped up the Cobra, and started installing the motors -- and found that two motors from the pack of three, all with the same 3D9 date code, were bulged enough that they required extreme pressure to go into the mounts.  In fact, a lesser rocket (say, one built by a child) might well have buckled a tube or had a fin torn off in the process of installing these motors.  As it was, however, I was able (finally) to seat all three motors and attach the retention nut, and then inserted the igniters and twisted their leads.

There was some delay after I pushed the button -- I wonder if my launch key isn't getting corroded and giving more resistance than it should -- but all three motors ignited and the rocket blasted skyward and recovered closer than the previous flights.  As I expected, all three motors slipped easily out of the mounts, the bulge removed when the propellant that produced it was burned off.

My theory is that Estes is using worn tooling to produce motors.  In this case, an oversize tube (which holds the preprinted case while the nozzle, propellant, delay, ejection and ejection cap are pressed into the case) is allowing the cases to bulge enough to be nearly impossible to insert in the stock motor mounts.  It's only a matter of time before this problem, if allowed to continue, leads to motor failures resulting from case debonding or simple case failure.  Even now, there are safety issues with motors that are too tight to install, but might then eject after the propellant burn off loosens them.

Regardless, this was the last flight of the day, and we packed up and left the field.  Next month's launch at this field is our annual contest, 1/2A Rocket Glider and Spot Landing.



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