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Author:
Steve Baughman

Web Posted Aug 27
© 1999
All Rights Reserved.

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DARS LAUNCH - BATF LEUP - LDRS XVIII NATIONAL LAUNCH

Austin, TX - This is the fourth of our regular series of online updates designed to help keep viewers informed of XRV program development and spread the word about significant launch events. Since the last update, XRV-series rockets were launched six more times, with two of these flights using the XRV Mk IV booster and four flights on the new Mk V booster. This brings the total number of flights in the XRV development program up to thirty-nine, with the total burned impulse now equivalent to 58,282.1 Ns since July of 1998.

XRV MK V REACHES 10,000 FT ALTITUDE AT DARS LAUNCH IN WINDOM

	The author and fully armed Mk V ready for a break in the clouds.  Photo by Andy Meadows

In order to test the recent version 0.5 avionics software upgrades in the XRV's Telemetry Microcontroller Unit (TMU), we scheduled two flights at a Saturday launch event sponsored by the Dallas Area Rocketry Society at the Wells brothers' launch site in Windom, Texas on July 17. After catching a Texas Rangers game in Arlington the previous night with rocket engineers Al Davis and Mike Hudgeons and a good night's rest at the five-star Chez Davis Resort, we began the caravan to Windom.

After searching the miles-wide launch area, we found the range head in a new location due to the crops present at the traditional site, and were pleased to find very low winds all day long with gusts to 5 mph and triple-digit temperatures. Though only a one day event, a respectable group had assembled to enjoy some vertical motorsport prior to the big LDRS launch in Kansas, still a couple of weeks away.

The XRV Mk IV was used for our first flight of this event, and was armed with the the new verion 0.5 avionics software, which allows 30 seconds of hi-res (20 Hz) ascent time. We selected a fast burning K1100T motor for what would be the 34th flight in our test program, and as is typical with this configuration, the Mk IV left the pad quickly enough to spoil any chance of snapping a decent launch photo. The avionics registered an acceleration of 16.7 g's, velocity of 413.7 mph, and an altitude of just under one mile. More importantly, the new avionics software was confirmed to be working exactly as designed. The rocket was recovered undamaged approximately 1/2 mile downrange.

The XRV Mk V reached 644 mph and 10,066 feet altitude on flight 35.  Photo by the author

With high confidence, we loaded up an Aerotech L850W motor for flight 35 in the XRV Mk V. Though the sky was cloudy, we waited for a window between the clouds and managed to launch straight up into the blue for a full 4.6 second burn. After burnout at a top speed of 644 mph, the rocket began a coasting ascent for an additional 21.5 seconds and reached over 10,000 feet in altitude by T+25.10s, at which time the avionics deployed the drogue parachute for the descent phase.

Memorably, just as the rocket arced overhead at 10,000 ft., a previously unseen commercial airliner could be seen passing directly above it at 30,000 ft., and the juxtaposition of these two aerial vehicles made for a fascinating exercise in depth perception.

With Mike Hudgeons acting as base radioman, and with Al Davis behind the wheel of his launch recovery vehicle (LRV), we vectored about 3/4 mile away to the general area of the landing zone to which we had tracked the descent visually. I hopped out of the LRV and proceeded to track down the rocket using it's XLF-3 radio transmitter. The signal indicated that we had slightly overshot the landing site and we backtracked a hundred yards or so to find the XRV in some fairly deep weeds.

The Mk V was recovered fully intact and undamaged, so it was declared ready for continued testing on an even larger motor in a couple more weeks, at the national rocket event known as Large and Dangerous Rocket Ships, or LDRS.

Flight data:  Flight 34  Flight 35 

BATF APPROVES APPLICATION, GRANTS LOW EXPLOSIVES USERS PERMIT

	The BATF LEUP expands your legal rights to work with larger amounts of AP propellant.  Graphic by the author

After a lengthy application review process, in July the Bureau of Alcohol, Tobacco and Firearms granted our official Low Explosives User's Permit (LEUP), expanding our legal entitlements with regards to the purchase and storage of ammonium perchlorate (AP) propellant compounds. Approval of the permit hinged on our ability to provide adequate storage facilities in the form of an approved Type IV explosives magazine, and thankfully we were able to negotiate a workable solution with a third party who maintains explosives storage facilities of the proper specification.

The benefits of holding a federal explosives permit are significant for anyone involved in high powered rocketry, since access to any propellant grain of over 62.5 grams in weight is restricted by the federal government. The LEUP allows for the storage of up to 50 lbs. of restricted access propellant within each Type IV explosives magazine on premises approved by the BATF. Without the LEUP it is illegal to store restricted access motors, period. Also, the permit enables licensees to engage in the interstate commerce of resticted access propellants and motor reloads. It is illegal for a non-permit holder to purchase propellant from out of state vendors or transport propellant across state lines.

Needless to say, without a BATF LEUP we would not have been able to participate in the LDRS event in Argonia, Kansas. To do so would have required either transport of propellant across state lines or purchase of it in another state, both of which are prohibited. As it turned out, the permit arrived with a couple of weeks to spare. We must mention in closing that each of the BATF agents we dealt with at three different offices were very professional, courteous, and understanding of the needs of today's rocketeers. I'd encourage everyone to think twice about handling large amounts of propellant without an explosives permit, and instead go ahead and fill out the federal paperwork to get a permit of your own. You'll be glad you did.

LARGE AND DANGEROUS ROCKET SHIPS XVIII

With a great deal of enthusiasm, and accompanied by Ed "Obi-Wan" Jacoby, we trekked north in late July to attend the 1999 national rocketry meet in Argonia, Kansas known as Large and Dangerous Rocket Ships. In order to fully demonstrate the capabilities of the XRV, we planned four flights over the course of the event, with the final flight suspected to break two miles in altitude and hopefully reach supersonic speeds.

After an overnight pit stop and ceremonial G80W-powered night launch at the Chez Davis resort in Arlington, we arrived at the expansive Kloudbusters launch facility in Argonia on the afternoon of Thursday, July 29 for the first day of the event.

	Austinites Ed Jacoby and Mark Carlson are serious rocket folks and good company.  Photo by the author

There were a surprising number of participants already in attendance, and thanks to our splitting up the 9-hour drive over two days we felt great. We excitedly picked up our registration packets and got to work setting up a suitable base of operations. After a couple of laps we spotted Austinite Mark Carlson, who happened to have some extra space near his campsite and offered to share his space with us for the duration of the event. We wasted no time in setting up our EZ-up sun shelters and breaking out the AP for our first flight of LDRS.

Flight 36 in the XRV test program used a 54mm K550W motor in the Mk IV booster, though with all of the successful flights made in this configuration in the past, it was less of a test flight and more of an exhibition. After prepping the rocket, I looked around and finally noticed that the winds were pretty high. Rumor has it it is like that a lot in Kansas. With only 90 minutes remaining on the Thursday FAA waiver, I knew that the time was right if I was going to keep with my schedule of one flight per day with incremental power increases on each flight. I filled out my range card and headed towards the range head to load the rocket on the pad for flight 36.

Loading up the XRV Mk IV for flight 36.  Video still frame by Ed Jacoby

After some initial confusion on the part of the pad manager, we were directed to an appropriate pad and proceeded to load the XRV Mk IV onto the launch rod. At this time we couldn't help but notice that in spite of the multi-thousand dollar launch control electronics, the launch pads for K-powered rockets were quite rudimentary, offerring no adjustment in azimuth or elevation. They were instead constructed like metal sawhorses or quadpods with a rod mount welded to the top, and thus offered no means of 'pointing the rocket' in any direction other than a region of the sky randomly determined by the shape of the ground the pad sat upon. The pad manager told me that "they wanted it that way". Aside from this minor inconvenience, I found the Kloudbusters to be consummate professionals who knew how to run a big launch properly.

	Flight 36 burned a K550W and reached 5443 feet altitude.  Video by Ed Jacoby

In spite of the concerns about launch pad integrity, the XRV Mk IV launched as expected, enjoying a 12.4g boost and a 19.25 second ascent to an altitude of 5443 feet, at which time the recovery system deployed the drogue parachute for a quick return to the Kansas countryside. The main parachute deployed at 600 feet, and the rocket touched down in a large field of jumbo-sized dry dirt clods which proceeded to batter the rocket parts as they were drug across the field by the high winds caught in the 60" main parachute. As we approached the rocket, it was evident that some repairs would be necessary, as the front of the avionics section was somewhat battered and caved-in with a multitude of dents caused by impacts with the dirt clods as the parts were dragged across the field. With no rain in recent weeks, the dirt clods may as well have been rocks with their hardness and ruthless disregard for my so-called quality workmanship.

The Argonia launch site is absolutely huge.  Aerial photo by Doug Gerrard

No problem. In true motorsports fashion, I immediately set to work 'in the pits' straightening out the dings and strengthening the weakened and fractured avionics airframe tubing with a generous application of cyanoacrilate. Within an hour the repairs were complete and the avionics section was stronger than ever before in spite of the addition of a few charismatic scrapes on the outer finish, compliments of the state of Kansas. High winds, hell - we were ready for Friday.

After a decent night's rest at the Oaktree Inn in Wellington, we arrived at the launch site bright and early Friday. First thing on the agenda was the procurement of a new launch pad from Dave Towers of Ground Support Technologies, which we used for the remainder of the event so as to have some control over the direction of our ascents. Sporting all-stainless construction, the pad offered a very sturdy launch platform and though it required some additional set-up for each launch, we felt that the expenditure was well worth it in light of the alternatives.

	Ground Support Technologies' launch pad provided solid footing for the XRV Mk V.  Video still frame by Ed Jacoby

Friday's flight 37 in the XRV development program was planned with a 75mm K560W motor in mind, and knowing that I had all day in which to fly it, I proceeded with the prep phase in a deliberate fashion. For this trip I had procured a rental cargo van from Enterprise car rentals, and the spacious cargo compartment offered a nice prep area and also doubled as an air-conditioned efficiency apartment in which to hide out from that big yellow thing. The hot sun was providing triple-digit temperatures and causing the Northerners in attendance to melt before our very eyes.

Incidentally, at a large launch event such as this, there are many occasions when rocket parts fall towards the spectator and prep areas, and one quickly becomes accustomed to the shouts of "Heads up! Heads up in the spectator area!". These episodes rarely involve any real excitement, as the rocket is usually under parachute and typically ends up landing in a bare spot somewhere admidst the crowd. In spite of this situation, on Friday we became an unwitting focal point of the launch as a level-1 certification rocket failed to deploy a recovery system of any kind and at apogee, pointed it's nose directly at the top of the Enterprise rental van from a couple of thousand feet up, and began accelerating in ballistic fashion at 9.8 meters per second per second.

An incoming ballistic rocket slammed off the top edge of the Enterprise rental van to everyone's great amusement. The nosecone was buried a foot deep in the ground and resisted removal.  Video still frames by Ed Jacoby

Thankfully, Mark Carlson was watching the action while I was prepping for flight 37 at the back doors of the van. Upon hearing Mark's shouts of "Heads up! Incoming! STEVE, INCOMING RIGHT AT YOU!" I looked up and saw a round dot with fins a thousand feet up, getting bigger and bigger. I could tell immediately that I was in trouble, so I launched myself away from the van in true cartoon character fashion, as fast as my two feet could take me. I'd estimate I pulled 1.7 g's with a max velocity of 25 feet per second. Before I even realized what was going on, the incoming rocket whistled in and exploded off the driver's side top edge of the van with a sickening shatter, and the remains buryed themselves in the ground right outside the driver's door. We then enjoyed fifteen minutes of fame as a hundred rocketeers from around the country came over to survey the damage to our rental van and offer their condolences. After glancing off the top edge of the van, the nosecone had buried itself in the rock-hard dirt down to about a foot in depth, and I am sure that a direct hit would have easily penetrated the sheet metal roof of the van. Maybe next time.

	Flight 37 burned a K560W in the XRV Mk V, reaching 7190 feet and 440 mph velocity.  Photo by the author

With that excitement behind me, I finished prepping the XRV Mk V with the K560W, set up the new GST launch pad, and grabbed the appropriate launch card for flight 37. Though I was hoping for calmer winds than the day before, my hopes were unfounded. The XRV Mk V lifted off in a stiff breeze and on flight 37, enjoyed a 8.43g boost during a 4.1 second burn to a maximum altitude of 7190 feet and top speed of 480 mph. At T+22.65 seconds, apogee was detected by the avionics package and the descent phase began with drogue deployment and eventual main parachute deployment at 600 ft. Unfortunately, the high horizontal windspeed again caused some damage on landing. This time, the booster section buckled slightly on impact, causing a delamination of the fiberglass in a 1" by 6" area around the circumference of the airframe approximately 1/3 of the way up from the nozzle.

I'm no stranger to field repairs, so that afternoon I immediately set to work. Harold Peebles generously allowed me the use of his on-site machine shop to grind away the delaminated fiberglass with a dremel tool, and on-site vendors had epoxy for sale that I purchased for the repair. I was able to barter some coldies from the Spoetzl Brewery in Shiner, Texas for a suitable piece of 6 oz. fiberglass fabric, and applied two layers to the affected area of the airframe in record time. After some finishing sanding on Friday night, the Mk V booster was again fully structurally sound and almost ready for Saturday.

Two layers of 6 oz fiberglass were applied.  Photo by the author

On Saturday morning, I finished off the repaired area with some touch-up paint and replaced the two checkerboard stickers that were removed to facilitate the grinding operation. After a couple hours drying in the sun, the XRV Mk V booster looked virtually blemish free and was ready to continue with the flight schedule. Saturday marked the arrival of launch recovery leader Marty Baughman, who generously provided a rental car to assist in long range recovery operations. We planned flight 38 of the XRV in the Mk V using a L850W motor, on which it had previously flown only twice before. The XRV flight team was not only ready, but also quite eager to demonstrate the XRV under L power for a national audience.

	An L850W rated motor was employed on flight 38, pushing the Mk V to 645 mph and 9450 ft.  Photo by the author

Using the L-rated motor had an additional benefit. All L motors and larger were launched from the prestigious 'away cell', thereby enabling us to avoid the long lines at the range head that were caused by the huge weekend crowds. We instead drove to the away cell pads immediately after our safety inspection and loaded the rocket at a more deliberate pace. After the countdown, the XRV Mk V tore off into the sky for flight 38 in our program, hitting 11.6 g's and 645 mph during a 24.8 second ascent to 9450 feet. When the drogue deployed, it only took a few seconds of descent for me to realize that the upper level winds were at a direction opposite to the winds at ground level. This meant that the rocket was going to drift far away. Sure enough, I saw the main parachute open just before disappearing over the horizon at least a mile away. Interestingly enough, flight data shows that at T+77.0s, the descending rocket entered a thermal at an altitude of 6574 feet which held it at that altitude for over 10 seconds before letting it continue downward under the drogue parachute.

The XLF-3 transmitter (top) and MNS-20 receiver (bottom).  Photos by the author

We clamored into the recovery vehicle and drove down one of the sectional dirt roads that crisscross every mile in this part of the country. With a landing out of visual range, it was time to resort to the trusty XLF-3 radio homing beacon housed in the nosecone of the rocket. We stopped the car after a half mile or so, broke out our MNS-20 receiver unit, unfolded the 3-element yagi antenna, and got an immediate signal further downrange. We drove for another half mile, stopped, and got another signal in the same direction. We continued to drive up almost to a bermed treeline, but this time no signal was detected on the receiver. Had we gone to far? I pointed the receiver to where we had came from, and again no signal. I knew then that we had not overshot the mark yet, instead the radio transmitter had to be just beyond the bermed treeline with the berm hiding the signal from me.

We parked the car and proceeded on foot, and just past the berm we reaquired the homing beacon from a direction in the middle of an absolutely huge bean field that was hip deep in height. We entered the bean field, walking carefully between rows, and spotted the main parachute about halfway into the field. Again the rocket showed evidence of a rough landing, with the laminate on the top of the booster section being somewhat fractured and creased from impact. It looked relatively minor, so I repacked the chutes and we returned to the range after a successful recovery of flight 38.

	The Aerotech L1120W motor was initially out of spec and required a slight modification to the liner.  Video still frame by Ed Jacoby

Flight 39 on Sunday was to be the culmination of many months of anticipation, as it would push the XRV faster and higher than ever before. Using the Aerotech L1120W rated motor, the Mk V would hopefully break two miles in altitude and perhaps reach transonic speeds. The weather looked bleak for most of the day, and the waiver wasn't opened until early afternoon due to high winds and cloud cover. The 6 lbs. of propellant to be used on this flight fit into a motor case rated at 5120 Ns, but unfortunately there were some problems loading the motor. During assembly, it was noted that the ablative phenolic liner which wraps the fuel grains was oversized in length by about 1/8", which kept the motor closures from screwing fully shut. After some discussion with Jim Turner of Trailing Edge Technologies, we compared the liner to one from another reload and noted the difference in length. Unfortunately the fuel grains were already installed, and their tight fit would prohibit their removal from the liner for use in a correctly sized one.

The final flight of the XRV Mk V was both spectacular and educational for the builder. 688 mph in 2.9 seconds.  Photo by the author

Jim Long provided a hacksaw, and I very carefully cut the excess length from the L1120W liner so that it would fit properly. With a little sanding on the edges the liner fit perfectly and motor assembly was completed. I prepped the ejection charges and I put a few wraps of clear packing tape around the top of the booster section to reinforce the weakened joint at it's top, at the booster to avionics coupler joint. It looked and felt solid. I grabbed the appropriate flight card and we drove to the away cell after being signed off by the range safety officer.

The Mk V was placed on the pad and armed for flight, while we backed away and positioned the recovery vehicle for ease of recovery and quick access to the dirt roads. I readied the radio tracking receiver and watched the rocket through binoculars as the launch control officer counted down and pushed the button.

The XRV Mk V screamed off the pad for flight 39, faster, harder, and louder than ever before. Then, at T+2.50 seconds, the intense airstream pressing on the nose of the rocket caused it to slightly buckle at the booster to avionics coupler section, and so began a hellish cascade of additional failure modes. The slightly misaligned top half of the rocket was ripped away within 0.4 seconds, at a speed of 688 miles per hour, and at T+2.90s the avionics package went dead after it's steel structural members buckled under the force. The front 14 inches of the booster section exploded in the airstream and the fiberglass on the remainder was peeled like a banana as the booster continued upwards to complete a full 5.1 second burn.

	The destruction of the XRV Mk V.  Video by Ed Jacoby

The drogue parachute was exposed to the airstream, and was ripped to shreds by the force of opening. The 1" nylon tubing holding the parts together was ripped at the stitches at the bottom, and the carabiner straightened out the eyebolt at the attachment point to the avionics section. The plywood bulkhead at the bottom of the avionics section was fully ripped out. The deceleration of the drogue shredding caused the upper main parachute section to detach, where the 600+ mph winds could get to work on the 60" main parachute. The forces were such that this section of the airframe was presumed to have disintigrated, as it was never found. The nosecone flew off, and the tracking transmitter was knocked free from it's housing.

In an instant, what was once an intact XRV Mk V was quickly separated into a booster section, drogue parachute and harness, avionics bay, drogue ejection baffle, nosecone, tracking transmitter, forward airframe section, main parachute with harness, and two Nomex heat shields, all incoming separately from about a mile up. To say it was pretty exciting would be an incredible understatement.

Thankfully, many of the important pieces were recovered.  Photo by the author

I tracked the booster through binoculars while Ed and Marty shot off in the rental car to chase down the main parachute, which was drifing away quickly (no rocket!) in spite of it's shredded condition. They found it 1 1/2 miles away. The booster section landed with a thud, and as I walked out to recover it I was helped by Ted Cochran, who had seen some of the parts incoming and helped me track them down. The level of damage was incredible, obviously a major malfunction and fully worthy of the retirement of the XRV Mk V. We were able to find the booster, avionics, nosecone, parachutes and harnesses. Ted even spotted my trusty XLF-3 radio transmitter buried about an inch down in the dirt after I homed in on it with the receiver. The parts tell the whole story, and will forever be in my personal museum.

And that's the story of how the XRV Mk V was totally destroyed after hitting a new top speed of 688 mph on the final day of the LDRS launch. The L1120W motor was the largest that would fit, and so perhaps it was time for a new vehicle anyway. Stay tuned for tales of the new and greatly improved XRV Mk VI.

Flight data:  Flight 36  Flight 37  Flight 38  Flight 39 

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