The Quest X-15: This is a "Sport-Scale" (not true scale) model of the famous X-15 rocket-powered research plane. This particular kit appears to be newer than other Quest X-15 kits described here: It is a few inches longer, and a recommendation by Quest to only use the A8-3 or A6 motors. (Mine is definitely too heavy to fly on an A8). I chose to paint my particular model gloss blue (not the historically accurate black).
Above is the modified configuration, with the payload section in white checkers.
Below is the "stock" kit.
My kit came out pretty heavy as I used a full-sized can of Rustoleum 2X paint trying to get a smooth, glossy finish. Apparently light coats of this paint leave the finish in something like an orange-peel texture, cool but not good for low drag. I discovered heavy, thick coats that would run with normal paints made for a smoother, glossy finish. But by then, there was so much primer and paint on this model that it almost doubled the weight of this kit. In MHO, Rustoleum2X (from Home Depot) sucks for flying models. I wish I would have used the ridiculously expensive yet lighter Testors stuff at $5 for a tiny 3-oz. can. Still, people comment on the nice, glossy finish.
Above: a look at the tail. Below, a closer look at the payload section.
This was only recently added, after the X-15 had a lot of flights already.
SPECIFICATIONS
Series Number: 18
Number of Stages: 1
Stock Length: 18.75"
Iris Payload Length: 3"
Total Length, tip-to-tail: 21.75"
Diameter: 1.378"
Wing Span: 6.25"
Stabilizer Span: 5.38"
Stock Empty Weight: 95 grams
Iris Payload Additional Weight: 13.6 grams
Total Dry Weight: 108.6 grams
Liftoff Weight Range: 134.3 - 139.6 grams
Motor Diameter: 18 mm
Motor Length: 70 mm
Motor Retention Method: Clip
Payload Interior Length: 2.5"
Payload Interior Diameter: 1.3"
Payload Volume: 3.32 cubic inches
Altimeter Capable: Yes
Recovery Method: 14" Plastic Parachute
Typical Descent Speed: 9 mph
Recovery Protection: Nomex
Shock Cord Mount Material: Kevlar
Wing/Fin Material: Balsa Wood
Launch Lug Size: 1/8"
Kit Brand: Quest
Completion Date: Sept. 2011
FLIGHT LOGS
2011, October 2: Penn Manor, Breezy, cold, drizzly
B6-2: Maiden Voyage of the X-15! Launched at a 15 degree angle into a moderate wind but she didn't weathercock very much at all. Only made about 100 feet it seemed. Good 2-second delay for this heavy bird. Even though Quest provided what seemed to be a reasonably long shock cord, the heavy plastic nose cone snapped back and took a nasty bite out of the leading edge of the right wing.
Shame I didn't photograph this model before flight. Good recovery but since it was only about 50 degrees F, the parachute sort-of froze stiff and never fully deployed. Landed close by in the grass. I expect this will fly better on a C6-3.
2011, November 6: Penn Manor, Breezy
C6-3: First C flight for this rocket. It flew well and had a nice recovery. I packed some dog barf in some wadding for this flight. When it landed, I asked myself "what's this odd black thing sticking part-way out of the tube?" Closer inspection revealed it was a Nomex cloth I installed and I completely forgot about it! Duh.
Appeared to go more than 200 feet, so I'll say 220 at least. (I should put an altimeter in this.) I wouldn't want to fly this on anything less; maybe I'll try a D10 because I built it tough enough. Although a B6 made for an OK flight, for fun flying it's just too heavy (3.4 oz) for anything smaller than a C.
2011, December 4: Penn Manor, Steady 10 mph wind
C6-3: I had high hopes for this seriously heavy X-15. Previous flights in winds demonstrated it will fly well anyways. I ignited a C6-3 that burned for 2.1 seconds, accelerating 1.9 Gs and peaking at 6.8 Gs. It reached a speed of 89 mph, still fighting the winds and remaining straight up. There was a 3.1 second coast time and it still kept going up despite the winds!
It then reached its apogee of 437 feet - much higher than anticipated. After dropping back to 413 feet the parachute ejected, descending under a good chute at 12 mph. The X-15 landed 28.5 seconds later. Since this model doesn't have a payload, the Altimeter was clipped to the nosecone and it survived OK, but for some reason I did not get a number for the time delay between apogee and ejection, all other numbers seemed correct.
2012, February 5: Penn Manor, Steady 10 mph wind
B6-2: On this fairly windy and cold day, I could count on this rocket to fight the winds and fly upwards and not disappoint. I was not sure if the cold would keep the parachute from unfolding or not, as my previous flights this day had all came down under a plastic wad. I was using a B6-2 in case it arched over a lot. This is its first B6 flight with an altimeter. It burned for 1 second and accelerated to a peak of 6.5 Gs, averaging 2.3 Gs during the boost. After that it reached a speed of 48 mph and coasted for 2.1 seconds to 138 feet, where the ejection charge fired.
It coasted another ten feet for another half second and then the parachute opened all the way at 148 feet. It descended at 7mph and landed quite close after 14.7 seconds. It looks like this model could fly with a B6-4 even in strong winds. The large body tube size meant that I could pack the parachute loosely, and I think helped it deploy in the 40-degree temperature.
2012, April 1: Penn Manor, 5-10 mph wind, gusty
I ignited the C6 which burned for about 2 seconds. It accelerated at a peak of 5.2 Gs, and averaged 1.8 for the burn. During this time the model slowly rolled and wavered in the gusty winds aloft as told by the wavy smoke trail, but it remained going up during the boost phase. This pushed the model to 87 mph as expected and then coasted for 3.1 seconds to an altitude of 336 feet, less than expected. During the coast phase it turned rapidly and surprisingly DOWNwind while still moving very fast.
As it started down it lost 57 feet and the upper winds took it far downwind before the slightly late ejection occurred 2.1 seconds later at 279 feet. The parachute opened well but again not completely and the model descended at a somewhat fast 17 mph. It landed safely without damage several hundred yards downwind after a flight time of 18.1 seconds. I call this a successful flight.
2012, June 10: Halifax, near calm
This model then reached a top speed of 56 mph. The actual delay was a full second short and occurred at 127 feet. After 1/10 second it reached an apogee of 149 feet (one foot higher than the previous flight) with the parachute still in the tube. The rocket continued down for a nervously long time with only the nose cone out.
Eventually the ‘chute was pulled out in the turbulence and it opened.The model descended at 12 mph and landed about 50 feet away. Flight time was only 11 seconds. As I expected, flights with this model would be much more impressive with a C6 motor, B6’s are hardly worth the effort.
C6-5: This is the last scheduled “test flight” of this model before it moves on to the role of sport flying. This flight will be used to verify that the C6-5 is the best motor for calm flying. After ignition this model gave some impressive numbers for acceleration compared to the previous two C-powered flights. Average acceleration was 2.5 Gs, and the peak was 8.8 Gs. Burn time for the motor was about normal at 1.9 seconds.
The model broke the 100 record with a top speed of 104 mph. It then coasted for 3.7 seconds to an apogee of 346 feet. Ejection came 7/10 seconds after apogee when the rocket fell 8 feet from apogee. With a good parachute deployed it descended at 9 mph, reaching ground about 200 feet from the launch pad. Total flight time was 30.1 seconds.
2012, June 30: Indiantown Gap, Erratic winds
C6-3: By now the wind was strong and persistent, making flying anything high or slow a one-way mission to a bad place. But I knew this Quest X-15 could handle it. She’s heavy and seems to just brush-off wind gusts like a brick lighthouse.
It had a good 2 second burn, and although it rocked and quivered, it continued straight – really straight up. It accelerated at 7.1 Gs peak, and 2.1 Gs average. After motor burnout, moving at 91 mph, it still kept going straight up for another 3.8 seconds! At 372 feet the ejection fired early, and 4/10 seconds later it peaked at 391 feet apogee. It probably could have used a -5 delay even in this wind.
The parachute popped out, but it looked a little funny and was falling in an odd way.
After about two or three seconds, the parachute appeared fully open. Apparently it got a bit tangled in the Nomex protection sheet until the winds opened them up. The descent was a normal 9 mph, and the flight time was 31.7 seconds. It landed about 240 feet from the pad due to drifting in the stronger winds. This is a good flight to end a long, hot and windy day.
The X-15 was modified with a 3-inch payload bay. Now the rocket can fly with the expensive altimeter safely tucked away from the strong shocks of the ejection, and I don’t have to rely on that single wire clip to hold tight. Furthermore, I get to see first-hand how much the added payload can affect the flights of these rockets, since I have a lot of flight data for this rocket without the payload bay.
2012, August 11: Halifax, 6-10mph winds, some gusting
The C6-5 burned for a nominal 2.1 seconds, and the peak acceleration was 6.1 Gs, about one half a G lower than without the payload section. The average acceleration was 1.6 Gs. That was enough acceleration power to get the X-15 flying to 73 mph, more than 10 mph slower than usual. It coasted for 2.7 seconds and then reached an apogee of 251 feet, or about 50 to 100 feet lower than average for a C6 motor. After apogee it lost 27 feet in the last 1.4 seconds before ejection.
This particular motor had a short delay time of only 4.1 seconds, and at 224 feet the parachute deployed and the X-15 descended at 9 mph to a soft grass landing 22 seconds after liftoff. This rocket tends to have a wide range of altitudes and speeds, so a few more comparison flights will show a truer picture of the performance cost of having a payload section.
2012, November 4: Penn Manor, 14mph winds, steady
B6-4: I chose this rocket because it flies well in winds, but because of the wind I limited the motor to
the B6-4. I didn’t take into account the data from previous flights and the added weight of the payload
section, or I would have used a -2 delay.
The motor lit and the rocket accelerated to 7.2 Gs peak, averaging 2.5 for the 8/10 second burn time. This got the rocket to a speed of 43 mph as it struggled a bit with the strong winds, although it still did fly straight. It only reached 99 feet at apogee, which occurred at 2.1 seconds after burnout.
Unfortunately it had a 4 second delay on the motor, so it continued down almost as fast as it went up,
reaching an average speed down of 22 mph. At a mere fraction of a second before impact, the ejection fired
and the chute opened up, but there was no time for the parachute to slow it down. The main body tube drove itself into the ground taking about a 1-inch core sample. The entire flight was over in 5.5 seconds.
The body tube suffered little serious damage, but the end was a bit chewed up. A slight tear in the
parachute on a shroud line showed that it did indeed slow the rocket down a bit before impact, but it was
still an ugly flight and taught me to not choose a motor so casually when it is windy.
2012, December 2: Penn Manor, 7 mph wind, no gusts
C6-3: Having almost lost this heavy rocket on the last flight by using a B6-4 with a too-long delay, I chose the C6 this time with only a -3 delay, believing that this rocket is not bothered by the winds and should have plenty of time to recover.
This was to be the third test flight of the rocket with its new Iris payload section added, with the first test using the C6-5 in calm winds successfully. The C6 fired up and accelerated off the pad while generating 6.5 Gs of lift, averaging just 1.4 for the whole 2 second burn time. During this time it curved far upwind maybe 800 feet or so. It reached a top speed of 63 mph but only 195 feet.
The ejection charge fired quite early after only 2.4 seconds, while the rocket coasted over and up an additional 4 feet to an apogee of 199 feet in the last 4/10 seconds. The stiff Quest parachute opened well and allowed this rocket to return at a safe 10 mph, while drifting down and back to the launch area. After a 17.6 second flight, it came to rest about 75 feet upwind from the launch pad, saving me a long walk.
I can see now that the addition of the Iris payload on this heavy rocket drastically reduces its performance, and seems to alter its stability (making it over-stable) so it is no longer a good flier in windy air. Without the payload section I have made 350 to 450 feet in this degree of wind. I am now trying to work out a method of carrying the altimeter in the rather large and hollow plastic nose cone instead.
C6-3: This was going to be the last flight of the day, and the last of the year 2012. Others have packed up and the remaining club members already declared “last flight”. I had few low-altitude choices left, so I decided to send the X-15 up again for one last flight, making this the fourth and final test flight of the Iris payload.
The C6 motor lit up and burned for 2 seconds. This time I got a weaker peak acceleration of 6.3 Gs, but the average acceleration for the burn was 1.5 Gs. That was enough to push the X-15 to a top speed of 66 mph. Not so great considering this model has flown over 100 mph on a C before. It turned into the wind again but not nearly as severely as the last flight.
This C motor also had a short delay of only 2.6 seconds. The ejection fired at 235 feet but this model wanted to keep flying, gaining an additional 23 feet for an apogee of 258 feet in the last 4/10 seconds. Again the parachute came out of the Nomex cloth and fully opened, letting this model descend at 10 mph.
The model turned south into the wind during the flight, but with the deployment it drifted west instead of north as expected, so it landed a good 150 feet away from the launch pad. The flight lasted 20.5 seconds and was a good success, and a good ending to a very interesting year of rocket flights.
This was the last flight of the year 2012. Thus ends my third year as a Born-Again Rocketeer.
2013, March 10: Penn Manor, 5-15 mph winds, 63 degrees, 18%RH
B6-2: The last time I flew this model with a B6-4 was a traumatic experience. The delay time was so long that it core-sampled the mud, so I have only flown it with a C6 since. This time I was going to try the B6 again, but with a 2 second delay which I thought would work much better.It ignited and took off fine, accelerating at 5.6 Gs off the pad and averaged 2.1Gs acceleration for the 9/10 second thrust burn. This was the lowest acceleration for any B6 motor so far. With that burn, it reached a top speed of 42 mph, a record slow flight for any motor so far. After a slightly long delay of 2.4 seconds, the ejection fired at 89 feet. The X-15 Iris had enough energy to continue climbing for another ½ second, coming to a stop at 95 feet apogee, also a record low. While the parachute deployed earlier than ideal, it was certainly preferable to the other B6-4 flight that deployed about 5 feet before impact.
As usual for this rocket, the rather strong winds didn’t affect the flight too much, and the parachute filled fully and brought the model back at 10 mph. Flight time was only 9.8 seconds. It landed within 50 feet of the launch pad.
2013, June 30: Fort Indiantown Gap, light winds, 70-90 degrees, 50-60%RH
C6-5: The X-15 was going to fly again for a unique test flight. I was about to compete in a 30-second duration contest, and my X-15 with the original Quest parachute was the one model with almost perfect 30-second flights. This was one last test flight to determine if I should use the 3 or 5 delay for 30 seconds.
To get those 30-second flights I had to remove the payload section and store the Altimeter securely in a newly-engineered hollow nose cone, and it was also to be tested on this flight.
The test flight went as well as possible. The motor lit and took the X-15 off the pad with 7.8 Gs, and the acceleration averaged 1.9 Gs for the flight’s 2 second burn. After motor burn-out it flew at 84 mph, coasting for 3.7 seconds to apogee at 376 feet. It then descended 29 feet before ejection at 5.2 seconds.
The ‘chute opened well and the rocket came back at 9 mph. It landed with a flight duration of 32 seconds – probably enough to win 1st place for the duration contest. I then loaded up the exact same motor type and parachute for the official contest flight. The last three flights were 30.1, 31.7, and 32 seconds, a good, consistent average!
C6-5: With the successful test flight, I now had to fly the contest flight. I was only allowed one rocket and one test flight, and this was it. To have a chance with this contest, I needed everything to be about the same as the last flight to hit 30 seconds exactly.
The motor lit, and the X-15 accelerated off the rail at 6.7 Gs, one G less than before. The 1.9 second burn averaged 1.9 Gs, which was good. It hit 81 mph, only 3 slower than last time. It then coasted for 3.7 seconds, just like the last flight also. It reached an apogee of 335 feet, 41 feet lower than before. With less altitude, the parachute had to open a bit quicker this time for me to make the 30 second mark.
Whereas the last C6-5 delayed for 5.2 seconds, this C6-5 only delayed for 4.8 seconds, only 1.1 seconds after the lower apogee. In fact the faster delay helped even out the flight differences, and this flight ejected at 315 feet, only 32 lower than the previous flight. There was still a chance of hitting close to the 30 second target.
The parachute hit the wind and became tangled and twisted to the shock cord elastic, so the canopy didn’t open at all. Instead of falling at 8 or 9 mph to a winning duration, it fell at 15 mph. The flight was over in 20.4 seconds, and my chances of winning was over as soon as the parachute and shock cord started twisting together. In 15 flights I never had a completely un-opened parachute on the X-15 before. Murphy, Hrumph! The bright side: There was no damage to this very tough rocket, just my pride.
2013, August 4: Exton Park, 10 mph winds, apx 72 degrees
B6-4: I was trying out a new field today. Of all the rockets that still needed a test flight, the X-15 was predicted to be the lowest. I wanted to try a lower-power test flight with the new altimeter in the nosecone. Though it was windy, I wasn’t worried about the X-15 since it is a wind-fighter and I expected it to go less than 150 feet up.
The motor lit promptly, and the rocket blasted off its 4-foot launch rod. It peaked its acceleration at 8 Gs while averaging 3 Gs for the 8/10 second burn. As the thrust began to fade it began to turn into the stiff breeze about 30 degrees or so.
The rocket reached a speed of 50 mph and then slowed as it coasted for 2.1 seconds where it then turned completely into the wind. The apogee of this flight was 99 feet. After apogee it delayed for another 1.2 seconds while dropping 17 feet.
The ejection fired a bit early after only a 3.3 second delay. At 82 feet up the parachute opened almost immediately, and the rocket descended at 9 mph to a soft grass landing. The total flight time was only 10 seconds.
2014, August 2: Halifax, 5 mph winds, 80 degrees
Quest C6-3: I brought the X-15 along because it is a good backup model
in windy weather, and I could use it to test a bunch of Quest motors. Glad I
brought it, as a questionable decision by the club to set up on the west end of
the field with east winds made high flights a bad idea for today.
As usual with the Quest motors, it took off with a roar and accelerated quickly, but then chugged along with minimal power for a long burn. The X-15 cocked a bit into the wind, and headed directly for the sun, it appeared to reach at least a couple hundred feet. A good parachute brought the rocket back safely, but apparently the altimeter was prematurely triggered (a consistent problem with Jolly Logic’s Altimeter 2), and I had nothing but invalid numbers. I had hoped to burn through three Quest motors to gather average data, but now I would need a fourth flight at least.
Quest C6-3: I flew a Second flight using another C6-3 Quest motor since the first one was falsely triggered. I packed the same motor, same parachute, and the same Nomex sheet into the rocket and used the same launch rod.
This flight seemed to start off as well as the first, but shortly after launch at maybe 40-60 feet it turned sharply towards the northeast and headed out like it was intercepting a target. The winds were fairly light, and generally coming from the south, south east, so that couldn’t explain the erratic flight path.
As the long-burning Quest motor continued to burn, the X-15 travelled farther and farther away down the field, going at best horizontal. By the time the delay charge drew a line of smoke in the sky, you could see the trajectory heading a few degrees downward. This was not going to end well.
As the rocket lost speed, it fell to earth, while probably still moving at least 77 mph (it’s average vertical speed with a C6). The flight path was more like a tight spiral, and the angle appeared to increase to about 10-20 degrees or more toward the earth, and then it fell out of view behind a small rise in the field.
At about that time the ejection was expected, but it was not seen and not heard by us three observers. My best guess is that it drove itself into the deep grass at a shallow angle, before the ejection charge fired. In the deep grass behind a small hill, we were not able to hear the ejection, and the parachute may not have even come out far enough to be seen. Or it may have been destroyed by the impact before the chute could eject. In any event the rocket could not be located even after an extensive search for hours. I suspect it is deeply buried in the tall grass.
The X-15 will likely never be found. The rocket with its thick gloss blue paint, the specially modified payload-capable nose cone, Nomex sheet, new purple parachute, and most sadly that expensive Altimeter 2 will never be seen or used again. Unlike the Bertha which was lost and recovered in this same field, this was not high in a tree, it was right there, but could not be located. So frustrating. And unlike the Bertha which had a tight payload compartment, the Altimeter was not protected from the rain, so it will likely be destroyed before long. It will either rot from the rain, or be chewed up or crushed by an industrial sized lawn mower.
I can only speculate what went wrong, as this model has often flown well even in winds so strong I wouldn’t have flown any other model. Its history of 17 successful flights disproves any theory about instability. I can speculate that the Quest motor’s clay nozzle had cracked or eroded and caused a highly vectored thrust, and in fact I don’t really trust Quest motor quality anyways.
Lesson learned: I have decided to never fly these smaller rockets in tall grass, as this is the second altimeter I lost in tall grass. I will stick to soccer fields and snow-covered fields, but not this low-lying jungle that is hard to walk through and impossible to find rockets in. There are many manicured fields to fly in, so those savannah-type fields are no longer an option for me, as I spent too many hours walking in them and not flying in them.
#Quest #X-15 #X15 #modelrocket
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