#251
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Black Shire--Draft horse in human form, model rocketeer, occasional mystic, and writer, see: http://www.lulu.com/content/paperba...an-form/8075185 http://www.lulu.com/product/cd/what...of-2%29/6122050 http://www.lulu.com/product/cd/what...of-2%29/6126511 All of my book proceeds go to the Northcote Heavy Horse Centre www.northcotehorses.com. NAR #54895 SR |
#252
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Just got out a couple of Semroc spacer tubes. They're spiral, but otherwise same as a casing. I think Carl was going to see if spirals could be used for his motors (I told him about the 1972 Estes mini motor experiments). And Carl told me he got them from the same company that does Estes' casings. one is 0.691 +- 0.001. The other is 0.688 +- 0.0005. But yes, I think the Estes tubes may have been 0.685 empty with planned expansion through loading.
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Roy nar12605 |
#253
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The current Quest Q-Jet motors have plastic cases, but as Klima showed, even composite motors can use paper cases successfully. Maybe in the future, Quest could also--not necessarily to replace the plastic-cased motors--make Klima-like motors of different "ratings." Even they might successfully use spiral-wound casings, if a sufficiently tough adhesive (phenol resin, maybe) was utilized.
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Black Shire--Draft horse in human form, model rocketeer, occasional mystic, and writer, see: http://www.lulu.com/content/paperba...an-form/8075185 http://www.lulu.com/product/cd/what...of-2%29/6122050 http://www.lulu.com/product/cd/what...of-2%29/6126511 All of my book proceeds go to the Northcote Heavy Horse Centre www.northcotehorses.com. NAR #54895 SR |
#254
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Quick update from yesterday: I flew five more Q-Jets. The A3-4s had KILLER ejection charges but otherwise worked well. Two of the B4-4s had what seemed to be overlong delays (these both from my first shipment, both dated 050118). The other B4-4 turned in a gorgeous and quite nominal-looking flight (motor dated 052918).
I had no ignition failures and no launches upon continuity testing (our well-experienced club system has incandescent indicators and does fire Q2G2s upon continuity check). I retained the igniters with a tiny piece of 1/16 inch heat shrink tubing, pressed into place with a bamboo skewer with the point clipped off, in each case. Upon revisiting the blue motor tube....now I'm not so sure about what I posted earlier. Some Q-Jets go into the tube that I thought was undersized just fine. More care in measuring and taking notes on my part is in order. I'm going flying with my son and grandson in a couple of hours. I will be flying a Semroc Mini Aero Dart on Q-Jets with an AltimeterThree aboard. That will let me get measurements of delay times and such - and graphs of same. I am suspicious that my first lot of "B4-4s" are really mislabeled B4-6s, especially after that fifth flight yesterday (Alpha III to 554 feet) looked entirely nominal including a deployment time consistent with a 4 second or so delay.
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Bernard Cawley NAR 89040 L1 - Life Member SAM 0061 AMA 42160 KG7AIE |
#255
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I went flying with my son and his son for Father's Day. I flew 9 Q-Jets and of those have good AltimeterThree data for five of those flights and partial data for two more (I'm working the "why" of the partial data with Jolly Logic). Two have delays reasonably close to the marked duration (one B4-4, one B4-6). The others were close to 50% over (~6 seconds for motors marked at 4). Essentially, all the B4s performed as if they were B4-6s save one. The two A3-4s I flew also seemed long, but I don't have onboard data for those two flights.
Good stuff: No misfires - 9 out of 9 went on the first go. I was using an Estes PSII controller with a 3s LiPoly inside for ignition. Strong boosts as befits a motor which comes to near full thrust very quickly. Bad stuff: EVERY ejection charge was violent. Some were downright frightening. This led to failed shock cords, snap back damaged fins and other rocket parts (and this with nice long shock cords that are part kevlar and part an elastic element). "Bonus" delays in most cases - often leading to deployments at high speed headed down. This along with the killer ejections led to quite a bit of damage. Of course some fit issues as we've been discussing, though I was able to do a sufficient job with sandpaper on a 1/2 inch dowel to get a label-less Q-Jet in the Nova Payloader I wanted to when they first arrived. It is now one of the models that needs repair. Much more when I have a chance to look at the data more closely.
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Bernard Cawley NAR 89040 L1 - Life Member SAM 0061 AMA 42160 KG7AIE Last edited by BEC : 06-18-2018 at 02:00 AM. |
#256
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Sure seems to me this first batch of Q-jet motors to reach the public leaves a LOT to be desired in the quality control department. Oversize diameters, "bonus" delays, and "warhead" ejection charges. Hope they have this all sorted out by the time they release the C and D motors.
I really want to try those but DON'T want to be an unwitting "Beta tester" !
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When in doubt, WHACK the GAS and DITCH the brake !!! Yes, there is such a thing as NORMAL, if you have to ask what is "NORMAL" , you probably aren't ! Failure may not be an OPTION, but it is ALWAYS a POSSIBILITY. ALL systems are GO for MAYHEM, CHAOS, and HAVOC ! |
#257
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Black Shire--Draft horse in human form, model rocketeer, occasional mystic, and writer, see: http://www.lulu.com/content/paperba...an-form/8075185 http://www.lulu.com/product/cd/what...of-2%29/6122050 http://www.lulu.com/product/cd/what...of-2%29/6126511 All of my book proceeds go to the Northcote Heavy Horse Centre www.northcotehorses.com. NAR #54895 SR |
#258
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Welcome to the Trough of Disillusionment
I'm quoting this from another forum or Facebook in the context of this topic, and thought it was funny. https://en.wikipedia.org/wiki/Hype_cycle
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-Wolfram v. Kiparski NAR 28643 - TRA 15520 MTMA Section #606 President |
#259
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One of our members flew a B4-4 in an Estes Monarch on Saturday.
He got the motor from Charlie at NSL. I do not know the date code since our club member removed the label for fit. Flight was perfect. Delay time seemed to be very close to 4 seconds - the longest I would estimate was 4.5 seconds. Ignition was perfect using the 3/64" heat shrink tube installed next to the initiator. Ejection charge was perfectly sized. I suspect that this was from a batch of motors produced after the initial feedback provided, as they stated that all motors were now being made with the reduced-to-proper-levels ejection charge. I have no idea why the first batch of B4-4 motors dated 050118 have the 6 or more second delay time. it would be pure speculation to guess that maybe the motors were either built with the 6 second delay installed or mislabeled. I'm itching to buy a very large number of all these motors since I like the performance and initiators.Just waiting to get official word of the casing diameter revision and updated instructions (which will include max liftoff weights for each motor and delay time as well as the info on using the 3/64" dia heat shrink which will be included).
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-Fred Shecter NAR 20117 (L2) Southern California Rocket Association, NAR Section 430 |
#260
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It's not just 050118 motors. One of my flights yesterday was a B4-4 with a 052918 date. Measured delay time (using AltimeterThree accelerometer data): 5.40s. See attached screen shot
Also A3 acclerometer data shows the thrust curve is shaped a bit differently than the package shows - not that that is particularly a problem, they still get to nearly full thrust pretty quickly. Attached is zoom in on one flight's thrust phase acceleration data. Unfortunately so far getting a 4 second delay in a motor marked as such seems to be the exception, rather than the rule. I've had two such flights out of 17 or so I've flown. I have flown one motor marked with a six second delay. It was actually 5.90s.
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Bernard Cawley NAR 89040 L1 - Life Member SAM 0061 AMA 42160 KG7AIE Last edited by BEC : 06-18-2018 at 12:42 PM. |
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