HISTORY AND MODS:
I got this kit as a package deal on eBay, it was extra cheap, but it had some damage. The main body tube suffered a minor crush, and the 1st stage tube did also. As a result, I had to cut this to be a little shorter than stock, but I was able to take the top few inches of the tube and with a coupler I could use it as a payload bay since I like payloaders anyway. As luck would have, the crush damage to the 1st stage body tube was minor and all under the stage coupler, so the added strength of the coupler made it useable as is.
I made a few minor mods to the kit. As already mentioned, the main body tube is a few inches shorter than stock. I glued in an ejection baffle and tied a Kevlar shock cord mount to this. The Kevlar length was just short of the end of the tube to prevent zipper damage. On the payload tube section I added static vent ports for an altimeter. I glued the fins a bit more forward than the instructions stated, to make it easier to insert/remove the friction-fit engines.
I intend to try to fly this with an under-sized parachute instead of the streamers. I find it easier to pack a quality Nylon 'chute than roll a couple of streamers up, and by varying the diameter, I can get a more controlled descent speed (Aiming for about 15mph.) I flew it with a 12" chute but it came down too slow, so I changed it out for a 9" chute for the next test flight, which also saved 5 grams of weight. I always fly in a large field and the rocket always lands in grass, so I don't expect broken fins.
I also tapered the cuts on the launch lugs, and added 1/8" lugs in case I want to fly it as a single stage. (The kit is supplied with larger 3/16" lugs and therefore requires a larger launch rod.) Because of the dimensional changes, I also had to change the exact location of the decals (not that the instructions were very clear about where they go in the first place!)
On many of my rockets, I placed a small mark between body tube sections so I can quickly orient them when assembling the rocket (nosecone-payload-body tube-stages). For some reason I didn't want to do that with this model, so I glued a small balsa strip that runs from the top of the 3rd stage to the base of the 1st stage when the stages were aligned as I wished. I then cut the strip at the joints, so I have a physical identifier that tells me the stages are all aligned correctly (including the alignment of all three fin sets.) It's a nice little detail that looks "technical", and will positively ID my stages if I ever drag-race another Comanche 3.
STAGING:
The last modification that I did, I apparently did without knowing it. Somehow, the 3rd stage 24mm engine sits aft about 3/16" too far, so it is not closely coupled to the 2nd stage nozzle. As a result, I might have reliability problems igniting the 2nd stage, and if it does ignite, an internal section of the 1st stage body tube will be exposed to pressurized exhaust gasses for a bit and will probably burn through and fail after a few flights. I re-checked all the dimensions of the rocket and reviewed the instructions again, but it all adds up OK. Did Estes make a mistake here? (note: later checking revealed that the 1st stage coupler has a hard to see glue fillet on the aft end that prevents the 24mm motor from going all the way in to ½”. THAT's where the missing 3/16" is!)
The 3rd stage tube is exactly 70mm to fit a C11 or D12 motor, but the motor is forced back by 1/2 inch because of the 1" stage coupler which is inserted and glued exactly 1/2" into the tube. The protruding motor is fine because it allows us to remove the empty casing. The 1st and 2nd stages are supposed to be offset by this same 1/2 inch aft, so they mate closely with the lower stages. I verified the 1/2 inch offset of the 3rd stage coupler, and also verified the 1/4" overhang of the motor in the upper stage and they are exactly as the instructions state. This 1/4" overhang pushes the mid-stage engine out by that same 1/4". So what's wrong? Should the mid-stage overhang by 1/2 inch instead of 1/4"?
Either way the solution is simple. The upper stage and the mid stage will work fine as is, but if I want to use the lowest 24mm booster stage - with or without the mid-stage, I need to add a 3/16" spacer (cut from a used engine casing) to the engine block of the upper stage to keep the motor out a little further, making it a close couple to the lowest stage.
This rocket has flown higher than the Gateway Arch in St. Louis, the Singer Building in NY, and the Washington Monument in DC.
I have flown twelve single-stage models using the C6-5 motor. Of them all, this rocket holds the speed record, having been measured at 133 mph.
I have flown twelve single-stage models using the C6-5 motor. Of them all, this rocket holds the speed record, having been measured at 133 mph.
SPECIFICATIONS
Serial Number: 23
Number of Stages: 1, 2 or 3
Main Body Tube Length: 27"
Mid-stage Length: 2.75"
Booster-stage Length: 2.75"
Length, All Stages Configuration: 39"
Payload Internal Diameter: 0.95"
Payload Internal Length: 2.25"
Payload Volume: 1.6 cubic inches
Diameter: 0.98"
Fin Widths (booster, mid, top): 3.0", 2.6", 2.0"
Sustainer Stage Mass: 60 grams
Mid-Stage Mass: 15.4 grams
Booster-Stage Mass: 14.6 grams
Empty Weight, all stages: 90 grams
Payload Modification Weight: 5.9 grams
Liftoff Weight Range: 89.5 - 186.4 grams
Upper Stage Motor Diameter: 18mm
Mid-Stage Motor Diameter: 18mm
Booster-Stage Motor Diameter: 24mm
Motor Retention Method: Friction
Motor Lengths (all): 70mm
Altimeter Capable: Yes
Recovery: 9" Nylon Parachute
Typical Descent Speed: 10 mph
Recovery Protection Method: Ejection Baffle
Shock Cord Mount: Kevlar
Fins: Paper Covered Balsa
Kit Brand: Estes
Completion Date: Dec. 1, 2011
FLIGHT LOG
2011, December 4: Penn Manor, Steady 10 mph wind.
B6-4: Maiden voyage of this rocket. I loaded it up with a B6-4, and then stuck the other two stages on as I carried it out to the flight line. On this windy day the remarks were priceless, as everybody thought I was about to launch a 3-stage flight and loose this rocket forever. Of course I removed the two empty stages before flight. The B6-4 burned for 0.8 seconds and accelerated this rocket at 4.6 Gs to 78 mph, reaching a peak of 12.4 Gs.
It then coasted for 3.1 seconds still going pretty much straight up before finally arching over to reach an apogee of 233 feet. It then continued for 1.5 seconds (a delay that was over 1/2 second too long) and fired the ejection at the altitude of 194 feet. It descended at 8 mph and landed in 21 seconds. I had hoped for a descent speed of 12 mph for when I multi-stage this rocket, so I guess a 12" chute is a little too much. Maybe a 10? Excellent flight and a good test before multi-staging this rocket.
2012, March 18: Penn Manor, Moderate wind.
C6-5: Test flight #2 for the 3-stage Comanche 3. This flight was also a single stage mission. After the successful but disappointing performance with a B6 in stronger winds, I tried a C6-5 this time in light winds. Summary in a word: Niiii-ce! During the 2 second burn it peaked at 10 Gs and averaged 3.1Gs. Top speed was 133 mph which allowed it to coast straight up to 660 feet. The ejection charge fired at 5 seconds exactly, but a bit before apogee, so the model stopped at 668 feet. It could have been closer to 700 feet with a -7 I think. The new, smaller parachute opened and it descended at 10 mph, better than before but still a bit slow since I intend to launch it with 2 or 3 stages and don't want it to drift into the next county. Total flight time was 49 seconds.
Although Estes doesn't recommend a -7 for the top stage, this test shows it to be necessary in light winds when it will have the additional speed of a booster or two! I don't intend to multi-stage this in stronger winds. In spite of its bright orange paint, I lost sight of this model. The flight video shows me wandering into the picture looking up, and then turning to ask "Eagle-eyes" if he has seen this model anywhere. As he answered, you could see it landing 4 or 5 hundred feet behind in the grass. After a multi-person random ground search for about 10 minutes, the rocket was found intact. I might want to add a shiny Mylar streamer to the parachute to aid visibility.
2012, June 10: Halifax, near calm.
C6-0 booster, A8-3 sustainer: Continuing the test flying for this new rocket, it was now time to test 2-stage flying. The wind was calm and perfect for test flights. I chose the lowest-power recommended engines for this first multi-stage flight, unsure how high it could really go and whether I would be able to see it.
George pressed the button and the rocket took off. Staging went well and the rocket continued straight up. The peak acceleration for the 2.3 second burn was 12 Gs, about the same as the single stage flights. The average acceleration was 2.5 Gs, not as high as a B6 or C6 single. The A8-3 sustainer fortunately had a long delay, but not long enough, and after a 3.5 second coast the ejection fired at 664 feet (a new high) and the rocket came to a stop at an apogee of 688 feet (also a new record).
Since the rocket reached 129 mph it continued up for another 24 feet in 8/10 second to apogee as the parachute unfurled.
Then the fully deployed nylon chute allowed the rocket to descend at 11 mph to touch down in grass barely 50 feet from the launch pad. Flight time was 45.4 seconds. Both stages were recovered in good condition.
B6-0 booster, A8-3 sustainer: The weather was perfect and there were many more test flights to do with this rocket. I decided the next flight was to directly compare the ability of the B6-0 booster motor to the previous flight’s C6-0. Both flights would use the same A8-3 sustainer. Although Estes did not specifically recommend this motor combination, I had confidence from my experience that the B6 motor has a stronger peak impulse than the C6 motor, so I knew it could handle the task of a booster, especially since the second stage propellant weight was only a tiny A8 motor.
I pressed the launch button and the rocket took off, staging only a hundred feet or so above the launch pad, then continued straight up. As expected, this flight recorded the highest ever peak acceleration of 15.6 Gs and the average for the burn of 8/10 seconds was 5.3 Gs – also the highest recorded. The short burn time only let this rocket reach 96 mph though. This A8-3 also had a long delay let this model coast for 3.6 seconds to 368 feet where the ejection fired. It continued up another 21 feet in 7/10 seconds to an apogee of 389 feet.
With a fully deployed parachute, it descended to the ground at 8 mph for a total flight time of 34 seconds. Even in the extremely large field of grass, it managed to find a landing spot on the stone path in the middle of the field, landing tail-first and nicking the trailing edge of the fins with cosmetic damage, as per Murphy's insistence. It was only about 40 feet from the launch pad.
OK, so not so impressive a flight and just shy of perfect, but valuable data was obtained. Overall I learned after these two flights that contrary to Estes recommendations, an A8-5 sustainer would be better than the A8-3, even with a low-power booster. I also learned that the B6, although a stout booster, just didn’t have the extra burn time to get this model really going, barely making half the altitude obtained with a C6 booster. On the plus side, it keeps staging low where it can be seen better and the booster stage remains fairly close to the launch pad.
B6-0 booster, B6-6 sustainer: I loaded the Comanche 3 up for a third 2-stage test flight.
Experimenting with low-power multi-staging flights again, I wanted to try a larger sustainer this time to compare the A8 vs. the B6 for a second stage. I decided to again use the B6 booster to keep altitudes under control and photograph the staging at a lower altitude.
Scott pressed the button and lit the booster. Ignition and staging went well, and although the specified burn times for the B6 motors is 0.86 seconds each, the Altimeter Two only recorded a 8/10 second burn time overall. Video confirms it was much longer. I do not understand how or why, the rest of the data seemed correct. Again this flight recorded even higher acceleration values, with a peak of 18.9 Gs and an average of 7.4 Gs, both very strong numbers. The rocket reached a record high velocity of 134 mph, although only besting a single C6 motor by 1 mph. Since two B6’s have about the same propellant as a single C6, this data does not show the 2-stage method as doing any better than a single stage, I suppose because the 2-stage has 2X the weight of the motor casing and engine nozzle as well as more fins. I expect a pair of C6’s would be phenomenal.
Whatever the numbers say, the flight went well and the flight path was straight vertical. In spite of the rocket using a 6 second delay sustainer motor, it fired early after only 4.8 seconds. This was the Comanche 3’s fourth-consecutive flight with a delay time less than ideal, which continues to limit this rocket’s altitude potential.
With the parachute deploying it traveled an additional 20 feet up in 7/10 seconds to a peak apogee of 628 feet. This also was not quite as good as a single C6 motor. This shows me that the B6-0 booster, although powerful, again does not sustain long enough to take advantage of its own liftoff strength. The C6 is definitely a more efficient low-power booster.
With a good chute, it descended to a grass landing at 14 mph. It landed only about 25 feet from the launch pad, and the booster literally landed at the base of the launch rod. Again, this was more good data, but not the motor combination I will use often. After three consecutive and successful 2-stage flights, it was time to give this rocket a rest for the day. Future flights will explore the use of both C6-0 and 24mm C11 and D12 booster motors. After that: 3 stages!
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2018, Nov 4: Penn Manor Field, 7 mph winds, 57 degrees F
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B6-4: Not wanting to brave the highest altitudes, I decided to make another low-power, single stage flight. Overall the flight data was fairly similar to the other B6-4 flight seven years ago.
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| The Comanche 3 is operating as a "Comanche 1" today. Here is the boost phase shortly after liftoff. |
It was a very straight and true flight, so that was awesome. It lit up and jumped, with a nice 12.4 Gs of acceleration, and burned for the usual 8/10 seconds. In that time it reached a speed of 74 mph, and the average acceleration was a nice 4.2 Gs, so it appeared as a quick launch.
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| This rocket flew straight and true, shrugging off the turbulent layers of air above. |
I’ve been plagued with short ejection times, and this was short but tolerable. Ejection was at a reasonable 3.4 seconds at an altitude of 251 feet, but it continued up for another 3/10 to an apogee of 256 feet, gaining its last five feet.
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| Here we see the Comanche emulating the Nike-Smoke project, where the smoke was used to create a visual indicator of winds aloft. I've seen this all day. The winds were not very strong, but steady, and seen here is the shifting layers of air in the lower 250 feet. |
I still used the small 10.5 inch chute normally only needed for high altitude, multi-stage flights, so it returned quickly enough at 10 mph. Duration of the flight was just 19.8 seconds.
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| Shortly after deployment before the canopy has fully opened and turned the rocket body around. The orange parachute is blocking our view of the fins. It left the wadding and smoke far behind. |
Since this was only the 2nd ever single stage flight with a B6, I can’t say whether this was typical or not, but the numbers were very similar to the other B6 flight, and it all ended well if not a bit muddy, about 80 feet downwind.
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May 25, 2019: Fort Indiantown Gap, Winds 5-10 mph, 70 degrees F
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C6-5: I had to scrub the first flight of another rocket because the shock cord didn’t pass inspection, so I started today’s flying with the Comanche 3, flying single-stage test flights. Although I wanted to fly more two if not three stage flights, the launch location and winds did not allow for safe flights.
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The winds were about 5 or 7 mph, from the south which would send the rockets into the swamp and tree infested area to the north, and the field was filled with tall grass that would have hidden any separated boosters. Therefore I chose to run some more single-stage flights to get a better feel for how the Comanche does with one stage.
The winds were about 5 or 7 mph, from the south which would send the rockets into the swamp and tree infested area to the north, and the field was filled with tall grass that would have hidden any separated boosters. Therefore I chose to run some more single-stage flights to get a better feel for how the Comanche does with one stage.
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This Estes C6-5 motor lit up with the usual flare. It accelerated the rocket with 10Gs off the pad, and burned for 2 seconds. Flying fairly straight up, it averaged 2.8 Gs for the burn, reached a top speed of 123 mph, and coasted for 4 seconds to an apogee of 542 feet.
This Estes C6-5 motor lit up with the usual flare. It accelerated the rocket with 10Gs off the pad, and burned for 2 seconds. Flying fairly straight up, it averaged 2.8 Gs for the burn, reached a top speed of 123 mph, and coasted for 4 seconds to an apogee of 542 feet.
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After turning over a bit, 7/10 seconds later the ejection fired at 4.7 seconds. At this point it was at 536 feet, having dropped only 6 feet.
After turning over a bit, 7/10 seconds later the ejection fired at 4.7 seconds. At this point it was at 536 feet, having dropped only 6 feet.
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.A good but small 10.5” parachute with a spill hole opened up, then the rocket descended at 11 mph to land in the grass to the northeast after a 39.9 second flight. Mission 1 was a success.
Although successful, this flight was much lower than the other C6-5 flight, which gained an additional 126 feet, and the speed was 10 mph slower. Both days had similar winds.
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C6-5: Another flight using the same motor would give me a true 3-flight average of the Comanche 3 on a C6-5. This flight fired off with almost as much peak acceleration of 9.9Gs. The burn was timed a bit longer at 2.1 seconds, and the average acceleration for the burn was almost as much at 2.7 Gs.
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.By all metrics this was a slightly slower burning motor, reaching a speed of 122 mph. I was lucky to get a slightly longer ejection delay also, with 4.8 seconds of delay. This slower burn combined with a longer delay allowed this rocket to reach a peak altitude of 581 feet, a good 39 feet more than the previous flight, but still 87 feet lower than its record.
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The ejection timing still limited its peak altitude since the ejection was at 571 feet, and 4/10 seconds before apogee which was achieved 5.2 seconds after motor burnout. In hind sight a slow burning C6-7 could have done better, but that would have been too long a delay for the first flight.
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I got another good parachute canopy, and the rocket returned at 11 mph. Flight time was 41.1 seconds, this time landing in very tall grass. The length and color of the rocket and parachute made it easy to find as it rested above the ground on the tall grass to the north.
I got another good parachute canopy, and the rocket returned at 11 mph. Flight time was 41.1 seconds, this time landing in very tall grass. The length and color of the rocket and parachute made it easy to find as it rested above the ground on the tall grass to the north.
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B6-4: With three C6 flights, I had a pretty good idea how the Comanche flies with that configuration. Now I wanted to try another low-power flight even though I already had data on two B6 flights already.
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This time the Comanche fired up well, shooting off the pad with an acceleration of 15.4Gs. That was significantly higher than the previous B6 flights. The burn time was 8/10 seconds, making for a typical 4.4G average acceleration. This brought the rocket to a predictable speed of 77 mph.
After a 3.7 second coast, the ejection at 250 feet, a full second early, slowing and stopping the rocket 7/10 seconds later at a final apogee of 257 feet.
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This time the Comanche fired up well, shooting off the pad with an acceleration of 15.4Gs. That was significantly higher than the previous B6 flights. The burn time was 8/10 seconds, making for a typical 4.4G average acceleration. This brought the rocket to a predictable speed of 77 mph.
After a 3.7 second coast, the ejection at 250 feet, a full second early, slowing and stopping the rocket 7/10 seconds later at a final apogee of 257 feet.
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I got another good parachute and spill hole, (home-made by the way), and the rocket fell at 10 mph to land in the grass safely. Flight duration was 19.7 seconds. Three flawless Comanche flights and no chance to safely launch multi-stage flights meant that it was time for the Comanche to rest until another time.
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I got another good parachute and spill hole, (home-made by the way), and the rocket fell at 10 mph to land in the grass safely. Flight duration was 19.7 seconds. Three flawless Comanche flights and no chance to safely launch multi-stage flights meant that it was time for the Comanche to rest until another time.
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Sept 21, 2019: Halifax PA, Winds 5 mph, 77 degrees F
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B6-0 & B6-6: I was too worried about risk to send the Comanche 3 up with two stages of high-power C motors, so I postponed the scheduled flight and instead thought I’d get a second test of a lower power configuration. I had hoped to arrive early enough in the day to launch before winds, but couldn’t. Still, I was in the mood for two stages, and with light winds and a large field, today was the day.
After securing promises for someone to track the booster, I gave the go-ahead for launch. The Jolly Logic altimeter recorded a burn time of 9/10 seconds, although I believe their numbers are in error. Three earlier single-stage flights returned expected numbers of 8/10 seconds, and so I would expect a correct timing to be more in the range of 1.6 seconds. This seems to be a regular fault of the Jolly Logic’s detection of two stages, and it may lead to faulty average acceleration calculations.
It recorded a peak acceleration of 16.2 Gs, higher than any B6 or C6 single stage flight, and similar to another B6/B6 flight’s numbers. Since a B6/B6 flight has both more overall propellant, more fins, and more motor weight the peak Gs should be less, not more than a single B6 flight, so I deduce these average acceleration readings are incorrect.
I saw staging occur at about 200 feet or less, and the upper stage continued much further upwards. The two stages of B6/B6 pushed the rocket to 122 mph, pretty good, but not as good as an earlier B6/B6 flight, and about the same as two other single C6 flights.
After a 6.3 second coast, ejection occurred at 575 feet. This was recorded at only 1/10 seconds before apogee, and it gained only an additional 12 feet. After a peak altitude of 587 feet, a good but small parachute appeared. I used a 10” chute with a spill hole to keep it nearby.
So far it was turning out as a perfect flight. It descended at a relatively rapid 11 mph, and landed safely in the grass maybe 150 feet or so away. The distance needed to recover it gave me the confidence to push the next flight a bit higher.
My overall assessment is that for the motor power, I can reach about the same altitude and speeds with a single C6 motor, so there isn’t much motivation to use a pair of B6s on the Comanche 3; Certainly not when I consider the extra effort and cost of a two-stage flight. It may be fun, but the engineering need is just not there.
C6-0 & B6-6: Having the confidence that it would remain in the field based on the previous flight, I chose a more energetic booster for the next flight.
This being a new motor combination, I had no real data to back me up about what to expect. I estimated 1100 feet, but that was nothing more than a guess.
This flight recorded a peak of 12.9 Gs, which might be accurate, but based on my witness of the flight which appeared to climb a bit slow, it may have been an error like B6/B6 flights have shown to be. With a recorded 2.4 second burn time, it might have captured some of the 2nd stages thrust time. In comparison, single C6 flights recorded times of 2, 2, and 2.1 seconds, so this only seems to have detected an additional .35 seconds of an 8/10 burn time of a typical B6 motor.
The average acceleration was 2.9 Gs, which seems in line with other C6 flights. No matter what those accelerations were, this rocket reached a top speed of 151 mph which was easily the fastest this rocket has gone.
I then had a 5.9 second delay time, ejection at 843 feet while still rising, and another 19 feet of travel in 4/10 seconds before the apogee of 862 feet was reached. This was also a new high for the Comanche 3. On top of that (no pun intended), the apogee was nearly perfect with ejection.
After another somewhat fast descent at 11 mph due to the tiny 10” parachute with spill, it was on the ground. It took over a full minute and another ½ second to land due to the height it started from.
I had another raging success for the Comanche and only about 200 or so feet to retrieve the rocket from the soft grass; while the booster was returned to me by a club helper. I don’t know where the booster landed, but I did see it falling nearby.
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