Gamma Ray

The Gamma-Ray was my first Quest kit. It features a translucent red payload tube, three swept fins, and plastic nose cone and transition section. The fin stock is pretty thick and sturdy, and I like the Kevlar shock cord supplied with the kit.  I painted it high-gloss metallic red with silver (stick-on) decals. I also added extra silver foil stickers to really make this model shine.

I had to add a lot of nose-weight to balance this model on a string stability test, but now it flies very well -
very straight.  The nose-weight was glued in to the tip of the plastic nosecone, so I still have full use of the
payload bay. The payload tube has vent holes added for a barometric altimeter.

It can get pretty far up there with B and C motors. I bought this kit cheap as part of a package deal on eBay, didn't give it much respect. But it consistently flies well and it is growing on me. I would recommend this model, but defiantly string-stability test it with a C motor and add nose-weight as necessary, or you might be very sorry you didn't.

Its light enough to fly very high, but the supplied 14-inch parachute is too large unless you really pack the ounces into the payload.  Even with a 18 gram payload and a 1-1/2 inch spill hole cut into the chute, it still descends at only 5 mph, allowing the wind to take it pretty far. The material Quest uses for parachutes also seems very light but too stiff, and often it will not unfurl even when plummeting down at about 30 mph.  I now use a 12” Estes parachute.

This Gamma-Ray currently has the lead in number of flights flown in my fleet. That alone should be a good
endorsement of this model.

I could probably get more than 803 feet if I try a C6-7 in this. This rocket has flown higher than the Woolworth Building in NY, and the Mellon Bank Center in Philadelphia.

SPECIFICATIONS

Series Number: 14
Number of Stages: 1
Length: 17.38"
Lower Diameter: 0.787"
Upper Diameter: 0.930"
Fin Span: 4"
Stock Empty Weight: 47.8 grams
Liftoff Weight Range: 71.8 - 79.3 grams
Motor Diameter: 18 mm
Motor Length: 70 mm
Motor Retention Method: Clip
Payload Interior Length: 2.25"
Payload Interior Diameter: 0.92"
Payload Volume: 1.5 cubic inches
Payload Tube Material: Translucent Red Plastic
Altimeter Capable: Yes
Recovery Method: 12" Plastic Parachute
Typical Descent Speed: 7 mph
Recovery Protection Method: Wadding
Shock Cord Mount: Kevlar
Noseweight Mass: 10.2 grams
Number of Fins: 3
Fin Material: Balsa Wood
Launch Lug Size: 1/8"
Glue Used: Titebond III
Paint Used: Testors
Kit Brand: Quest
Completed: Dec 1, 2010

FLIGHT LOGS

2011, May 29: Indiantown Gap, Light wind

A8-3: First Flight: Perfect Flight, although not very high. Altimeter was not charged, so not onboard. Altitude was estimated at 99 feet.

B6-4: Perfect Success. Onboard altimeter. First B flight for this model was definitely high enough even with all the nose-weight. I imagine a C would be spectacular. Did not drift very far at all. Reached apogee at 360 feet.

2011, July 2: Indiantown Gap, Light wind

C6-5: Perfect flight and recovery. Sailed out of sight for awhile. Altimeter read 803 feet - wow.

A8-3: Perfect flight and recovery. Somehow, this model never gave me any trouble - it must be the metallic finish!  Apogee was 112 feet.

2011, September 3: Indiantown Gap, Light to moderate wind

B6-4: Good first flight of three test flights to demonstrate repeatability of altimeter. This flight measured 390 feet. Good recovery.

B6-4: Wind picked up to about 10-12 mph for the second of three flights to demonstrate the repeatability of the altimeter. The rocket weather-cocked a lot during coast and by the time ejection fired, the rocket was horizontal at 326 feet according to the altimeter. Good recovery. This pretty much shows that the wind is a much greater factor in affecting height than any altimeter error which may exist.


This series of tests would have been more informative in zero-wind conditions.

B6-4: Third test flight to observe the repeatability of altimeter. A good flight but not as high as first flight, at least wind didn't turn rocket sideways during coast to apogee this time. Good, safe recovery. Altimeter read 361 feet.

2011, October 8: Penn Manor, Light wind

B6-4: The Gamma-Ray never gave me any trouble - until this day. The sky was clear and calm. I cut a spill hole in the parachute to see if I could get it to drift a little less this time. It certainly didn't drift! (Read on)

The motor burned for 1.2 seconds and propelled the craft to 72 mph.  Peak acceleration was 7.7Gs with an average of 2.7Gs. You would think with that kind of speed and acceleration this model went up a few hundred feet at least, but the altimeter read 6 feet. Six! I could have thrown it higher than that!

Obviously an altimeter error, although the static vents were inspected and not blocked. Looked like about 300-400 feet, so I called it 360 based on an average of four previous flights with this motor. All the other numbers from this flight were either absent or outrageous.

After ejection, the rocket came down fast under a plastic wad. For some reason the crinkly-plastic chute didn't open. I was careful packing it - I even packed it a second time because it just didn't seem right the first time. As it was falling I expected that this wasn't going to end well for the Gamma, but at least I'll get an interesting descent speed if the altimeter survives. But I got nothing, the data was blank. The rocket, with its thick fins landed in the grass intact, but I'll call this test flight a total failure. NOTE: Same problem, altimeter triggered by acceleration - not pressure - problem now corrected!

2011, November 25: Penn Manor, Moderate wind

B6-4: Good flight and recovery. Haven flown this before with an altimeter, I expected a flight to the mid to 300's in altitude. The actual apogee of 381 was a bit of a surprise on this cool, breezy weather. What I didn't know was that the Gamma was capable of reaching 98 mph and acceleration of 14.6 G's. She coasted for 4.3 seconds and ejected at 354 feet and took another half second to reach 381 feet.

Normally a slow descender, I added a 1-1/2 inch spill hole to the supplied Quest parachute, so she descended at a faster 5 mph, and the landing was only a few hundred feet away. I had to wait over 45 seconds before it was safely back on firm soil.

A8-3: I thought I'd send the Gamma up again with a smaller motor. This flight peaked at 13 G's but only to reach a top speed of 47 mph. Losing that bit of speed, it coasted another 2.2 seconds before reaching an apogee of only 99 feet and began to descend in its arc for another 0.6 seconds.

The ejection fired on time when it descended only 7 feet from apogee. The ejection charge sounded very powerful. It then drifted down under a full canopy for a 13.8 second flight.  Inspection revealed the body tube above the fins almost split along a spiral seam and the body tube was a bit soft in that area. It apparently was a very powerful ejection charge.

2012, April 1: Penn Manor, 5-10 mph winds, gusty

A8-3:The A8 fired for about 6/10 seconds; propelling the rocket to 46 mph. Acceleration was 3.4Gs and peaked at 8.4Gs. It then coasted for 2 seconds to an apogee of 99 feet, hardly affected by the wind gusts. The apogee, speed and acceleration were lower than normal for this model on an A8-3. After apogee it coasted an additional 1.3 seconds while falling 19 feet before the ejection fired.

The plastic parachute ejected but did not open, and the rocket fell at a fast 27 mph, for a flight time of only 6.1 seconds. I had hoped to test the new spill hole I added to the 'chute to reduce the slow descent. It was not very cold, about 50 degrees F. It landed in the grass undamaged though. The ejection charge was a bit late, at 3.3 seconds.

B6-4: Ideally, a B6-6 is best for this light rocket, but in the stronger, gusty winds I expected a lot of
weather-cocking and a lower apogee, so I chose the -4.  After the A8 flight failed parachute deployment, I thought a B6 would give it plenty of time to open, but not so.

This second attempt at testing the 1-inch spill hole in the parachute did not work either, even though it was above 50 degrees F. The B6-4 motor burned for 8/10 seconds, accelerating the rocket at 5.4 Gs, peaking at 14.6 Gs. It reached a top speed of 98 mph. These typical performance numbers exactly matched a B6-4 flight five months ago. No strong gust arrived, so this rocket continued straight up during the 4 second coast. Still rising, the ejection fired a bit early at 366 feet, and stopped the rocket at an altitude of 375 feet 6/10 of a second later.

Again the parachute failed to open up, and the rocket fell the 375 feet at 22 mph, landing in the grass undamaged 15.8 seconds after liftoff, instead of the expected 45 seconds.

2012, May 26: Indiantown Gap, 5mph wind

C6-7: It was time to try for an altitude record with the Gamma Ray Payloader, now that its parachute issues seemed to be resolved.  I sent it up last year to just over 800 feet on a C6 motor, but it only had an altimeter on board and I couldn’t see it at altitude to judge the best delay.

For this flight, it also carried an accelerometer to measure speed and ejection timing, which I estimated from lower flights that a delay of 7 seconds would be optimal.  The weather was hot and humid, perfect conditions for maximum altitude.

The launch was uneventful and successful, with the acceleration peaking at 14.9Gs.  The 2 second burn averaged 3.8Gs, plenty to prevent any winds from altering its vertical flight path significantly.  At motor burnout, it reached a speed of 167 mph. The motor’s delay was short – only 6 seconds and the ejection fired at 882 feet while still rising. In another 3/10ths of a second it reached a peak altitude of 897 feet, having gained an additional 15 feet while the new Estes parachute deployed fully.




It then descended at a safe 9 mph, and remained aloft for a total flight time of 69.5 seconds, the Gamma Ray’s longest recorded flight.

Even though the new parachute allowed for twice the descent speed of the Quest supplied chute, it still drifted pretty far, but I was pleased that it reached the highest altitude recorded, and also the fastest speed recorded for this model. 100% good flight.

2012, June 10: Halifax, near calm

B6-6: The previous two test flights with a B6-4 motor showed it could use an additional ½ second delay to reach the highest apogee, so I loaded a B6-6 for this flight.  A lot of my recent motors have come up short in delay times, and this particular B6-6 only had a 5.1 second delay.

Liftoff was good with a peak acceleration of 13.5Gs, averaging 4.7 Gs for the 0.9 second burn. Both acceleration values were a bit less than the previous two B6 flights, but it still reached a maximum speed of 96 mph (vs. 98 for the others). Going straight up, the model then coasted for 4.4 seconds to an apogee of 370 feet, very close to the other two flights.

After apogee the model fell for only 7 feet in 7/10 seconds and the parachute deployed. The model then descended at 10 mph to land about 150 feet from the launch pad in the grass.  Total flight time was 28.5 seconds.  A good flight, although post-flight inspection found a broken shroud line on the Estes parachute.

The break was not at the canopy attachment as expected, but in the middle of the string where apparently the line had been frayed and weakened. It did not appear to negatively affect the descent speed, as I tried to cut a spill hole in the previous unreliable Quest parachute to get a faster fall time. 10 mph is ideal for this model for its flights to 800-900 feet.

2013, May 4: Halifax, 5-10 mph wind, 70 degrees

B6-6:  All of the Gamma-Ray’s previous flights with a B6-4 showed that it could use some more delay time to reach higher altitudes, so I made a second test flight using the B6-6 motor.  The old retro-fitted Estes parachute seemed to be sticky and almost impossible to open up with my fingers, so I changed it out for a new 11” homemade purple parachute.

The motor lit well, and the Gamma tore off the pad with an acceleration of 14.5Gs, the motor burned for 9/10 second with an average acceleration of 4.6Gs.  With that, it reached a top speed of 92 mph. It then coasted for 5.6 seconds while still traveling upwards.

At an altitude of 313 feet, the ejection charge fired 4/10 seconds early, and as the parachute deployed it came to a stop at an apogee of 360 feet. It may have reached 400 feet if the ejection wasn’t so short.  The new homemade parachute with its extra-long shroud lines then brought it safely back down at 6 mph, landing softly in the grass at least a few hundred feet downwind. Flight time was 38.5 seconds.  This was the fourth perfect flight for today.

2014, July 20: Gloucester College, 85 degrees, 8 mph winds

B6-4:  I was a bit concerned with the altitude the Gamma would reach in the wind, but I shouldn’t have as the wind shifted to the larger recovery area, and I chose a parachute so small that I thought that even if it doesn’t work, I’ve seen the Gamma fall from many hundreds of feet several times with no parachute and no damage.

I sent it up with a small 10” chute with a spill hole instead of its usual 13.5” chute with spill.  Again I had hoped to test a B6-6, but the annoyingly strong winds held me back to a -4.  In retrospect, a 6 second delay would have worked fine.

The metallic-red rocket fired off with 11.8 Gs and burned for 9/10 seconds, averaging 4.9 Gs for the burn. It reached a top speed of 93 mph – all record low for the B6 motor although the burn time was 1/10 longer.

 

At 352 feet the ejection fired after a 3.2 second delay, and in the next 6/10 second the rocket gained 10 feet to reach an apogee of 362 feet. The small parachute opened cleanly and the rocket began a descent at 10 mph. It landed about 300 feet downwind after a flight time of 27.5 seconds.

2016, April 17: Cross Keys Field NJ, 66 degrees, 34%RH, 5 mph winds, no gusts







 

C6-7:  I’ve waited a long time for a day like this.  Dry air, moderate temperatures, little wind and no gusts, and what pilots refer to as “Severe Clear” skies.  I’ve kept the Gamma Ray on the ground, patiently waiting for a calm day where I could again push it to the maximum.  The ‘ray
has used a C6 twice before, but only once with a -7 delay.

 The first puffs of smoke appear as the propellant lights. It won't be long now, only a fraction of a second!

Shortly after the igniter wire glowed red-hot, she lifted off the pad with 11.6 Gs of acceleration, and burned for 2 seconds.  That was not a strong jump off the pad compared to most other flights.   Averaging a modest 3.4Gs for the burn, it was still enough to get the ‘ray travelling up to 146 mph.
After motor burn out, it coasted for the next 6.2 seconds.  A little short on the delay, but that was all that was needed as she peaked out at 845 feet altitude and dropped 12 feet in the last 1/10 seconds.

The Estes C6-7 builds up enough pressure and begins to push the Gamma-Ray upwards.

Don't mind the glider to the left. That's Bruce's rocket waiting for the epoxy to cure on the motor mount.  Later, it flew great!

The ejection was at 833 feet, and the small 10.5” chute with a spill hole opened cleanly. That let the Gamma-Ray descend at 11 mph, just rapidly enough to prevent it from drifting far away.

Well into the 2-second burn, the Gamma-Ray streaks skyward on a column of smoke,

t's altimeter and accelerometer taking measurements continuously.

 

The rocket landed without harm in the grass about 250’ away after a flight duration of 57.7 seconds.  No records were broken, but a satisfying flight that went straight up and very high was completed successfully.

Way, way up there now. Passing beyond 800 feet above the ground,

it is only visible because of the tracking smoke.

 

 

 

C6-7:  Another attempt to push the Gamma-Ray to the “top”.  Seeing both this and other rockets land close by, I was assured there were no strong winds aloft.

Bruce the launch ‘dude’ pressed the button and the C6 fired up quickly.  It cleared the pad but without a lot of energy, peaking at only 12.2 Gs.  The altimeter did record a longer burn though at 2.1 seconds.  During this time the rocket averaged 3.2 Gs acceleration, the lowest of any of the last 10 motors in this rocket.  That was just enough push to get the ‘ray to a top speed of 146 mph – identical to the last flight and bested by only one other Gamma-Ray flight.  This particular motor had a very short delay charge, only 5.5 seconds.





Another low-view of the Gamma-Ray at lift off.  In this one, I captured some burning bits of rocket debris being thrown from the steel blast pad.  At first I thought is was just stray grassy bits, but close examination of the file shows a white-hot core on all those little bits.

 



Just like the last flight it turned over after 5.6 seconds, at an apogee of 860 feet.  The second highest apogee recorded for this rocket in 17 flights.  Just like the last flight the ejection came 1/10 seconds after apogee and a 6 foot drop at an altitude of 854 feet.  That was the smallest drop for this motor in this rocket.

 Here we go again with another C6-7 motor.  Nice flaming tail.

This time the Quest Gamma-Ray flew even higher.

It looked very high like before but this time the wind seemed to hold it a little longer and let it drift a bit longer.  Fortunately it was easy to spot the grayish tracking smoke in the clear blue skies.  The small 10/5” chute and its spill hole kept it in range though while it descended at 11 mph.

A somewhat slower & longer-burning motor this time pushed the rocket even higher than the flight 1/2 hour ago!  The gamma' had its share of parachute woes, but it has always flown well.
 

It landed safely after a flight duration of 59.9 seconds.   Just a 1/10 second more and it could have joined the exclusive 60+ seconds club with its only other member (for this rocket) being a flight from 4 years ago.  Can’t complain.  It flew fast, straight and high, came back without damage about 350’ downwind and didn’t get lost!  That was the Gamma-Ray’s 18th flight.

2016, September 3: Fort Indiantown Gap,

73 degrees, 10 mph wind, gusty.

A8-3: This was to be the second of two flights of the Gamma-Ray with an A8
motor. There were two flights before, but that was without the Altimeter 2 which
measures speed and acceleration. There were two more flights with the Altimeter 2, but
one did not have a good ‘chute, so there was no valid data on return speed or flight
time. A second test would confirm the results of the first test flight. It was windy,
but I wasn’t expecting more than about 100 feet on this flight.

This flight used the same sized 13.5” parachute, but this one had a 10% spill hole and
weighed almost one gram more.


The ignitor burst into flames and the rocket took off with 13.7 Gs, highest of the A8
motors.  It burned for ½ second with an average acceleration of 4.7 Gs, average for the
A8 motor.  It reached a top speed of 34 mph, which was very significantly slower by
12.5 mph for the A8, and in fact the slowest flight ever of the Gamma-Ray.

It then coasted with not too much wind cocking for 2.5 seconds and turned over at an
apogee of 122 feet.  Although it wasn’t a long burn time, it made the A8 altitude
record. Another 7/10 seconds passed and the ejection fired after it dropped 10 feet. I
got a good ‘chute there at 112 feet, and it returned at 12 mph. When the parachute did
deploy properly, this was actually the slowest return speed for this rocket even with
its spill hole. It was sunny, so it may have caught a bit of a thermal boost. It landed
about 80 feet downwind.

With 19 documented flights, the Gamma-Ray now is the 3rd most flown rocket in my
collection (tied with the lost X-15), and the most flown in my born-again era, not
counting my old rockets from the 1970’s. As the first flight of the day this was a
successful though quick 10.2 second flight, and it told me I could go higher on my next
flights with other rockets.

#quest #gamma-ray #rocket #modelrocket