#101
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Quote:
__________________
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 |
#102
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Nope.
The ejection charge blows all at once and is finished. It can be much stronger than what you are used to. The continued burning/roasting is the "Hibachi Effect" and is from the delay afterburn. It is like a road flare inside your rocket. Google it. https://www.google.com/search?q=hib...lient=firefox-b https://apogeerockets.com/education...ewsletter28.pdf https://www.youtube.com/watch?v=b-8gsP2xI2M Play it slow and stop it several times near the end. Quote:
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-Fred Shecter NAR 20117 (L2) Southern California Rocket Association, NAR Section 430 |
#103
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It's that "hibachi effect" to which I was referring. It's cooked the insides of several of my LPR models that I put D10s or D21s into.
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Bernard Cawley NAR 89040 L1 - Life Member SAM 0061 AMA 42160 KG7AIE |
#104
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Quote:
__________________
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 |
#105
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The hibachi effect is caused by drilling fixed length delays from the ejection side rather than the motor side.
Just Tech Jerry |
#106
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Yep. We always drilled ours and inserted the hole facing the propellant grains our EX motors.
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I love sanding. |
#107
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Well...if it's from drilling delays then what is going on with D10s and D21s? Whatever you choose to call the effect, they will burn a BT-20-based model through in one or two flights and bubble the paint on a BT-50-based model after one or two flights.
In any event, one hopes that the Q-Jets aren't quite so prone to burn the insides of the models they are used in as the Aerotech D10/D21 do.
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Bernard Cawley NAR 89040 L1 - Life Member SAM 0061 AMA 42160 KG7AIE |
#108
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Why would anyone use a D10 or D21 in anything BT-20 or 50 based rocket unless it is a fire-and-forget flight ? Not likely to get it back unless the field is huge.
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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, TURMOIL, FIASCOS, and HAVOC ! |
#109
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I haven't actually flown anything BT-20-based on a D10, but I have flown something (Estes Astrobeam) that had a Bt-20 stuffer tube. The second use of the D10 burned it through. It's too bad because the D10 was what that heavy thing really needed. O at least a C5-3. After that I built an original BT-60-based night flyer with a 24mm motor mount that is better lit and lighter than the Astrobeam.
I've also flown a Nova Payloader on a D10 several times. It goes to about 1700 feet on one (while carrying an AltimeterOne) and it's really quite a satisfying flight on a large enough field (and with a reefed 'chute). But the paint bubbled just above the motor mount after the second such flight and I didn't do it more than a couple more times. That particular model was retired after its 75th flight due in large part ot the body getting really soft there just above the motor mount. It would have retired sooner if there had been more D10 flights. I'd have to go back through the log books but I think there were three or maybe four over its active lifetime. I get the opportunity to fly at a field big enough for such stuff several times a year.
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Bernard Cawley NAR 89040 L1 - Life Member SAM 0061 AMA 42160 KG7AIE Last edited by BEC : 04-18-2018 at 11:51 PM. |
#110
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If (hopefully not jinxing us here! :-) ) the Quest motors do still have the "historically hot" ejection charges, a possible fix could be to "paint" those prone-to-softening portions of the body tube (and/or stuffer tube) with something like a thin, wicking CA, epoxy, or polyurethane glue, or with polyester resin (it stinks until it cures, but it's as hard as stone once it does).
__________________
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 |
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