Tripoli Austin - Spring 1999 Launch News

Finally, a launch on the first attempt! Skye Dance XIV roared into the sky Sunday, January 10th, 1999. Sandwiched between 2 windy days, the Sunday weather was perfect; skies were clear with winds of 10 mph at launch time dropping off to near calm by sunset. Over 13,200 newtons were burned in 20 flights during the 4 hour waiver, with most of the flights happening in the last hour when the wind became calm. As usual, several rockets were not flown due to darkness. The average motor flown was 660 newtons, a small J.

Jeff Cook rejoined the high power community at Skye Dance XIV, finally completing the replacement for his trusty and long lost Scarecrow. Jeff showed off his brand new Aerobee Hi, a semi-scale model of the famous sounding rocket by Rocket R & D. Jeff's modifications of the kit include zipper-proof construction, dual barometric recovery, and fiberglassing of the entire rocket. The rocket has a 54mm mount and Jeff uses an Adept RAS2 recording altimeter for data collection. For his first flight, Jeff chose an Aerotech J350. The rocket roared into the sky (on the second Copperhead) and deployed right at apogee. The main charge fired on schedule at 250 feet and the rocket was recovered undamaged. Max altitude was 3,024 feet. For his second flight, Jeff chose a J275, which sent the rocket up to 3,749 feet. Again, everything performed flawlessly and the rocket was recovered undamaged.

Benton Reed flew his Public Enemy Honest John, this time on a J415. The rocket reached a max altitude of 3,718 feet, and landed close to the pads thanks to dual barometric deployment. Rumor has it that Benton has a K550 ready to go for the next flight (uh-oh). Benton also flew his THOY Phoenix on an I211. The rocket deployed right at apogee, but the chute tangled on the way down and did not deploy. The rocket hit hard, but was completely undamaged. Benton builds them strong (and beautiful).

Tom Montemayor put up 4 flights, including his LOC Bruiser on an Aerotech J800. The rocket reached a max altitude of 2,454 feet and deployed right at apogee. Even though the surface wind was almost calm, the rocket landed over half a mile away. Tom also flew Spectra on a Kosdon J450 to 3,211 feet, and his Hawk Mountain Bad Attitude on an Aerotech I435. The 9 pound rocket reached a max altitude of 1,315 feet on the 38/600 blue thunder reload, and landed less than 50 yards away using dual deployment.

Mark Carlson put up 5 flights, including his mighty Skyraider on a K550. The huge 25 pound rocket thundered into the air, and used an altimeter backed up by the motor to deploy it's chute right at apogee. There were a few heart-stopping moments as the big chute streamered, but after several seconds it inflated normally and the rocket landed safely. The altimeter was beeping out 1,390 feet as peak altitude. Mark also flew his PML Eclipse on an Ellis Mountain J330 motor to an altitude of 3,110 feet, and his Arcas on a long burn J135 to 2,895 feet. Mark also suffered a case of the wrong propellant in the reload kit, using an H242 blue thunder reload in his 38/240 motor. Upon ignition, the motor identified itself as a black jack by it's thick black smoke and began staggering up the launch rod. It took over 1.5 seconds to clear the rod and immediately arced over into the wind. Fortunately, the chute deployed right at burn-out (it was a blue thunder delay) and the rocket was recovered undamaged. A puckering flight! Peak altitude was about 30 feet.

Ed Jacoby flew his modified PML Eclipse on a J275 to 3,608 feet. The rocket used an altitmeter for dual deployment, but both chutes deployed at apogee. This produced a longer walk than anticipated, but the rocket was recovered undamaged. Peak altitude was 3,608 feet. Early deployment of the main chute is a common problem with dual deployment systems. Either shear pins, or a tight nose fit is necessary to prevent the nose from falling off while the rocket is descending under the drogue. Fortunately, this type of malfunction does not damage the rocket, it just means a long walk.

Rick Taylor put up his scratch built Dufus on a core I357 airstarting 3 outboard G80s. The I357 gave the rocket considerable speed off the pad, which was fortunate because the G80s were not in any hurry to fire. They sputtered and chuffed all the way up, and eventually 2 of them fired. The flight remained vertical, reaching a peak altitude of 2,380 feet. Dual barometric recovery brought the rocket back close to the pads.

Other successful flights were put up by Anthony Taylor, Tom Kindel, and James Reimund. All flights recovered successfully and undamaged.

Skye Dance XV took to the skies on Saturday, January 30th (Super Bowl Saturday). The launch was scheduled to start at 1:30, but strong winds caused a 3 hour delay. The first rocket lifted off at 4:30, and when the winds finally dropped off near sunset, there was a burst of activity in the last 30 minutes. Turn-out was small (only 6 fliers) since most fliers didn't think the wind would ever let up.

It was a most interesting launch since EVERY flier had some sort of technical difficulty, ranging from fairly minor to catastrophic. In spite of the high experience level of Tripoli Austin's fliers, the FORCE was not with us for this launch. Maybe it was the Blue Moon....

Mark ("Wind? What wind?") Carlson put up the first flight of the launch, flying his PML Eclipse on an Ellis Mountain J330. This was Mark's sixth flight using the economical Ellis Mountain motor, and it was to be his last using that particular case. The rocket boosted normally, but before the motor burned out we all heard the unmistakable "pop" of a spit nozzle. Mark's dual barometric recovery functioned perfectly, and the rocket made a safe, soft landing. The altimeter indicated a peak altitude of 1,550 feet, much lower than previous J330 flights. Upon reaching the rocket, Mark noticed that not only was the nozzle missing, the aft centering ring was also missing. Inspection of the motor revealed a case rupture which blew through the motor tube and allowed hot gasses to pressurize the area between the motor tube and the airframe, blowing out the aft centering ring. Mark also flew his modified Mini-Mag on an I211 and his THOY Phoenix on an I161.

Jeff ("What happened to Scarecrow?") Cook flew his Aerobee Hi twice, choosing the Aerotech 38mm J350 for his first flight. The rocket boosted fast and straight, and deployed it's drogue chute right at apogee. The rocket descended normally under the drogue for over 20 seconds (certainly a low stress phase of flight), then, amazingly, separated. The fin section fell to earth, while the upper section deployed it's main chute right on schedule at 250 feet and landed safely. Strong construction techniques and glass reinforcement allowed the fin unit to be recovered with no damage. Inspection revealed the failure was caused by a bad weld in the swivel hardware. The weld was covered with chrome plating so the poor workmanship was not visible before the failure.

Since Jeff's rocket suffered no damage, he reconnected the shock cord (without the defective link) and flew again, this time on a J460. The 8.5 pound rocket boosted fast on the Blue Thunder load, reaching a max velocity of 657 feet/second and a max loading of 17 Gs. This time recovery was perfect, with the altimeter indicating a peak altitude of 3,667 feet.

Tom ("Who invited all these kids?") Montemayor was a little worried about the wind, and flew his Hawk Mountain Bad Attitude on an I435 rather than the J460. The rocket boosted straight and true and right at apogee deployed it's drogue chute. Just as the chute deployed, we all heard the dreaded CLANK as the upper and lower sections collided with each other. The barometric recovery functioned perfectly and the main was deployed at 250 feet. The altimeter indicated a max altitude of 1,294 feet. Post flight inspection of the upper section (housing the main chute) reveal a gash in the side like it had been hit with an axe. In fact, it had. The leading edge of the fiberglass fins is as sharp as a razor, and at deployment one of the fins cut right into the upper section. The upper section will need replacement, and a much longer shock cord will be used.

Steve (Techno-Wizard) Baughman was ready to have the first successful flight of the day. Steve was flying his XRV MK IV, a highly modified and instrumented EZI, on a J460. This was a landmark flight in the history of this rocket, as this would be the first flight where the onboard electronics fired the deployment charges. Steve doesn't use ready-to-fly altimeters, he designs and builds his own. For this flight, Steve was planning to fire the drogue at apogee (backed up by the motor) and the main at 550 feet. The boost was perfect, riding a hot blue flame the rocket roared to over 3,500 feet. Then, right at apogee, the drogue charge fired. The rocket descended under it's drogue to 550 feet, where the main charge fired and the main deployed. The rocket was descending under a fully deployed main, all was under control, then it separated! Again, (we've seen this before) the lower unit fell to earth. As with Jeff Cook's flight, the failure was traced to a defective swivel which broke open. Effective immediately, I have removed all swivels and other assorted sail boat hardware from my rockets. Until they make titanium, mil-spec swivels, I'm not using them. Anyway, Steve's rocket was completely glassed and suffered no damage.

The next flier who attempted to break our streak of bad luck was Marvin ("Of course I'll get it back") Smith. Marvin had (past tense) a gleaming metallic colored minimum diameter 54mm rocket. The rocket used an ACME fin canister and an altimeter for two step barometric deployment. Marvin chose an I211 for the inaugural flight, and the rocket went screaming into the air. The metallic covering ocassionally caught the sun as the rocket turned over and we could see it sparkling way, way up there. Then......we waited for the apogee charge to blow. Nothing. The rocket made for the center of the earth fast, screaming all the way down. An unmistakable sound of tortured air molecules trying to get out of the way. The 250 foot charge did fire on schedule (about .0000001 second before impact) and got the nosecone off the rocket. Upon impact, the expensive altimeter gave it's life to protect the aluminum motor casing behind it. We were hoping to get an altitude out of the pulverized altimeter, but upon inspection of the thousands of pieces of printed circuit board, pieces of integrated circuits, and PIECES of resistors, we concluded that no information could be extracted from the debris.

In spite of all he had seen, Steve ("I'll get it to light THIS time") Rogers was ready to attempt his level 2 certification flight. Steve chose a long burn J135 motor for his certification flight, boosting a scratch built rocket utilizing barometric recovery. This particular motor had over 5 failed ignition attempts at previous launches; Copperheads, Firestar matches, Davey Fires, all were ignited successfully within this motor but did not ignite the motor. This time, using a robust Firestar, the motor finally roared to life and lifted the rocket into the twilight sky. At 3.5 seconds into the 7 second burn, the motor suffered a blow-by, and the rocket began tumbling end over end with fire coming out both ends of the rocket ("I hate it when that happens"). The shock cord bulkhead failed under the high deceleration and the charred lower section fell to earth, while the upper section successfully deployed at 250 feet and landed safely. Post flight investigation revealed no evidence of assembly error. Both o-rings and the back up ring were still in place at the forward end of the delay insulator and showed no evidence of leakage. The thrust had come through the center of the delay column. Our best guess as to the cause of the failure is a void in the delay column. This void, or bubble, in the delay column could have been up to 1/4 inch in diameter and would have allowed the delay column to burn out while the motor was still thrusting. Though this is not a classic blow-by (which usually means hot gasses getting past the o-rings), it still results in thrust coming out the forward closure.

"It wasn't my fault" is the standard cry you hear from a rocketeer whose expensive rocket has just fallen to earth in pieces. For Skye Dance XV, I think it was a valid claim. Two of our failures involved recovery hardware (swivels and quick links) that had flown previously and looked perfect. One damaged rocket was caused by just bad luck - sometimes the upper and lower sections hit each other when the chute deploys. In another case, you sure can't blame the flier when the motor spits it's nozzle and blows it's case open. In still another case, a perfectly assembled delay column decided to burn completely through in just over 3 seconds, while leaving the o-rings perfectly intact and still concentric. Finally, just because the altimeter beeps continuity, it doesn't guarantee that the ejection charge will fire. The flash bulb may fail to fire, the powder may fail to ignite, or the continuity may be through a short somewhere else.
There is some luck involved in this hobby; even the most skillful and experienced rocketeers have failures. That's why we stress redundancy for certification flights, two totally separate means of deploying chutes. Of course, we do expect a perfectly assembled motor to work properly, and we do expect quick links to hold. You can't make EVERYTHING redundant. Don't be discouraged....we'll do better next time!

NTHP 14 roared into the sky Valentine's Day weekend (February 13 -14) 1999. Sponsored by the Dallas Area Rocket Society (DARS - www.dars.org), the launch was held at their Windom launch site, about 1 1/2 hours northeast of Dallas. Conditions were ideal; skies were clear, temperatures were in the 60s, and surface winds were virtually CALM. Only two Tripoli Austin members made the 5 hour drive, Steve Baughman and myself, Tom Montemayor.

Tom Montemayor put up 3 flights on Saturday, the first being his scratch built Dynacom, "Unshredable", on an Aerotech L952. This was the same rocket Tom used last year at NTHP 13 to achieve his level 3 certification on an M1419. This year, Tom saved a little money and used the L952, a 98mm full L (5120 newtons) motor. The 7 foot tall rocket weighed just over 30 pounds all up, and utilized 2 step barometric recovery. At 11:20 am Saturday morning the button was pushed and the big rocket thundered into the air. Inital acceleration was low; at T + 1.0 seconds the rocket was only 33 feet high, and at T + 2.0 seconds was only 150 feet high. The progressive motor kept on pumping, and the rocket eventually reached a peak velocity of 744 feet/second. Peak altitude was reached 25.1 seconds after liftoff when the onboard Adept altimeter indicated 8790 feet. The rocket deployed it's 18 inch drogue chute at apogee, and a 96 inch main chute at 750 feet. The rocket landed safe and undamaged slightly less than 1 mile away.

Tom also flew his LOC Bruiser on an Aerotech K550. The 14.5 pound rocket accelerated fast (11.2 Gs), reaching a peak velocity of 616 feet/second at T + 2.1 seconds. Maximum altitude was 3455 feet, where the altimeter, backed up by the motor, deployed the main parachute. The big rocket drifted down slowly, landing safely about half a mile away.

Finally, Tom flew his scratch built Spectra on a Kosdon J450. The 6 foot tall, 4 inch diameter rocket accelerated at 13.4 Gs to a peak velocity of 569 feet/second, and reached a max altitude of 3027 feet. Two step barometric recovery brought the rocket down extremely close, landing between 2 parked cars in the pits, less than 10 feet from Tom's van.

Steve Baughman had a great weekend, launching his Experimental Rocket Vehicle Mark IV (XRV Mk IV) a total of 6 times, 4 on Saturday and twice on Sunday. On Saturday, Steve used every case in his 54mm system, launching the XRV on a J275, a J415, a J800 and a K550. On Sunday, Steve again flew the rocket on a J415 and a K550.

The XRV is an EXTENSIVELY modified LOC EZI, standing in at 6.5 feet tall and weighing 10.75 pounds. The most important modification Steve made to the EZI was to glass the entire rocket. The glassing greatly increases the strength of the rocket and allows it to be flown on larger motors. An unmodified EZI will shred on a J415 or larger motor (I've seen them shred on J275s), but Steve's all glass rocket can easily handle all the 54mm motors, including the high thrust, short burn, Blue Thunders.

Steve also modified the rocket to allow two step recovery. Two step recovery is very important for high flying rockets because it greatly increases the probability of finding the rocket after landing. This recovery technique involves deploying a small drogue chute or streamer at apogee (allowing the rocket to descend fast), then deploying the main parachute when the rocket is close to the ground (usually around 500 feet). Most fliers use commercially purchased altimeters or accelerometers to determine altitude, while others use timers set to the predicted time to apogee.

Steve designed and built his own electronics package for the XRV Mk IV, using an accelerometer and a pressure sensor to determine altitude. Steve samples pressure and acceleration 20 times/second during the boost phase, which allows not only altitude, but velocity and acceleration to be computed with high accuracy. For the K550 flight, the onboard electronics measured a peak acceleration of 10.75 Gs which occured at T + 0.35 seconds. Max velocity was 607 feet/second at T + 2.7 seconds, and the rocket reached a max altitude of 6060 feet at T + 18.3 seconds. The rocket descended under a small drogue to 500 feet where the main parachute was deployed. The rocket recovered safely and undamaged from all 6 flights.

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