30 July, 2017

30 July, 2017.

After a busy week, we have a range report from the 23 July launch at MDRA.  We made a total of 5 flights. Jenn (she’s the model holding the ALS-72 on the site here) and I arrived at the field about 9:40.  The weather was Maryland Summer: add in a bit of Old Bay and you could have steamed us like a blue crab between the heat and the humidity.  Winds were light–this side of 10MPH.  and we got our site set up in short order.  She’d never been to a launch before, and as she’s going to be leaving us to move out to Nevada with her beloved, Paul,  she figured that if she was ever going to see a launch, this was the time to do it.  She was a big help in prepping, setting up and tearing down camp, and keeping an eye on the rocket when the sun got in my eyes.  We’re going to miss her.

Pem-Tech Kraken

0.4lb recovery weight.

Jolly Logic Altimeter Three
Jolly Logic Chute Release, set at 200′.

Our first flight of the day didn’t go as well as we would have liked.  In attempting a different packing technique for the Jolly Logic Chute Release with our BLS-15 in small airframes, we found it to be a delicate balancing act between sufficient bulk to release the stock rubber band, and thinly-packed enough to exit the airframe.  We erred too far on the first option.  Apogee was 476′, and the chute never cleared the airframe.  Landed at ~40 FPS with a core sample.  The chute release was found to have been open–so the method WOULD have worked, if it’d cleared.  Gah.

Conclusion: Revert to prior technique, change bands for small chutes.
Rocket status: under review, likely flyable.


Pem-Tech King Kraken

3.28lb recovery weight

Jolly Logic Altimeter Three
Jolly Logic Chute Release, 300′

Our Pemberton Technologies King Kraken waking up the neighbors on a Sunday morning.

Clearly, if you have a sub-optimal LPR flight, the appropriate response is to fly a motor 10 times as powerful.  The CTI H-123SK is a fair motor for the King Kraken.  Normally, she flies on 3-grain I motors at this field (the CTI I-180 or -212) but for testing purposes and availability, it’s a lot more cost effective to fly on H’s.  We had this 2-grain 38mm sitting around doing nothing, so… why not?  The Jolly Logic Altimeter Three was not turned on for this flight because the author of this flight report was an idiot and forgot to press “record” while in bluetooth range.  We’d flown this chute in this rocket before at around this weight, so we were expecting a gentle descent.  The chute release performed flawlessly, and it recovered gently, close to the pad without damage.

Conclusion: still a great chute for this weight class, if using dual-deploy.  The flier may want to consider a BLS-36 for apogee deployment, depending upon field size, because with a BLS-42 popped at 2, 500+, you may land in the next county.

#3: Pem-Tech King Kraken

Mark X prototype
3.28 lb recovery weight
Jolly Logic Altimeter Three
Jolly Logic Chute Release, 300′

The 29mm H-226 is a fun little motor to fly.  We ran an adapter, and prepped as normal.  The Mark X prototype chute was packed the night prior, so it was a

King Kraken, CTI H-226, Mark X prototype, Chute Release

simple affair to cut the delay, throw in the step-down, load the motor, heave a couple handfuls of dog barf, attach the chute and close her up. Mark X is a 36″ diameter, 12-gore prototype of a chute we are not yet offering for sale.  The Mark X prototype was designed to correct the helicoptering noted in the Mark IX version, as well as increase performance slightly.  The launch was an unintended drag race with another flier.  LCO goofed and flipped a switch wrong, so we got no photos of liftoff.  We did, however, get the descent pics, which, for us, is the main thing anyway.  Apogee was 2041′, and the rocket descended with bound chute at a nominal 54FPS.  Landing was at 16 FPS, and the descent under inflated main was stable and pulseless.  We would have liked to have seen it come in a smidge slower than the 16FPS –that was the ultimate goal.  As it turns out, our Cd is still around 1.7–which is good, but not quite where we would want it.

Conclusion: better in that it did not helicopter and was a pulseless, stable descent.  Still want to see the descent rate slower.  Mark XI will be coming soon.

#4: Pem-Tech Bucky Jones, Space Cadet

BLS-30, Horizontal Recovery
2.5lb recovery weight
Jolly Logic Altimeter Three
Jolly Logic Chute Release, 300′

Bucky Jones, CTI-H-135, BLS-30, Chute Release

We love flying this rocket.  The 4-grain H-135 white motor is perfect for this little slab of retro SF goodness–gives it a nice kick in the ass to get it off the pad, sends it about a half-mile up, and has the horizontal recovery to protect its swoopy fins.  I’ve honestly lost count on how many times I’ve flown this rocket on this motor combination.  This was, however, the first time we used the chute release with it.  I wondered how it would work with the bound parachute and the horizontal system.  Apogee was 2,180 feet, and it landed at 13 FPS.

Conclusion: The chute release method of dual-deployment with horizontal recovery worked okay in this instance, but the horizontal tether did become entangled around one of the fins.  The bound chute did not have the drag necessary to keep the line taut to prevent entanglement.  We were lucky.   In the future, we may work on figuring out a way to have a drogue in-line with the main–but there is limited space to work with.

The Bucky Jones, Space Cadet typically recovers very slow on a BLS-30 –around 13 FPS.  I know: crazy.  But it has been consistently this speed.  It can’t be hitting THAT many thermals, and the horizontal recovery can’t be adding THAT much drag.  Maybe it’s magic?


Scratch-Built AIM-54c Phoenix

Our scratch-built AIM-54c Phoenix leaving the rail.

6.25lb recovery weight.

Raven 3
Jolly Logic Altimeter Three
Jolly Logic Chute Release, 300′

Since this model spent a couple of months in the tree and I had to pay to get it back, I have resolved to fly the Hell out of this thing.  It owes me.  The 6XL 29mm I-243 white motor gives a nice flame-to-rocket ratio, and gives this thing enough rail speed to fly

Our scratch-built AIM-54c Phoenix, weighing 6.3 lb in this photo, is landing under a BLS-48 main canopy at 12 FPS.

straight.  This marks the fourth or fifth time this motor had been used in this rocket, so we expected a  straight launch leading to a low flight to ~1,500 or so with a landing speed of  “slow.”  We were not disappointed on all accounts.  Apogee was 1,432 feet, descending at 57 FPS under bound chute to 300′, with the BLS-48 exceeding any reasonable expectations and setting down 6.25 lb at an unbelievable  12 FPS.

Conclusion: Perfect chute for this rocket

AIM-54c Phoenix, CTI I-243, BLS-48, Chute Release

While flight #1 could have went better, it was not without learning something in the process: go with the first method, and use even smaller rubber bands than that which are supplied.  Now that we understand that, we’ll accept the bit o’ crunchiness to the Kraken and move forward.  Flights #2-#5 were fantastic, and Jenn got to see firsthand the special brand of rocketry that is MDRA.  We left shortly before the thunderstorms rolled in and drove back to PA in the vomiting down rain.


Can’t wait until next month!