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  #261  
Old Yesterday, 09:52 PM
Jerry Irvine's Avatar
Jerry Irvine Jerry Irvine is online now
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Quote:
Originally Posted by Shreadvector
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).
I occasionally agree with you.
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  #262  
Old Today, 12:58 PM
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blackshire blackshire is offline
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I wonder if, in haste, some motors were either mis-labled or had the wrong delay charges installed (or if the tolerances [or settings] of the equipment that made/installed the delay charges might have been off).
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  #263  
Old Today, 01:12 PM
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I strongly suspect that my B4-4s are mostly mislabeled B4-6s based on data I have in hand. But a couple of them - one from each of the two date codes I have - have been correct.

Since all the ejection charges have been far more than needed I wonder if there was simply too much specified....perhaps thinking based on other Aerotech products for much larger models.

I agree that tolerances of both delay grains and ejection charges need to be looked at.
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  #264  
Old Today, 01:38 PM
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Shreadvector Shreadvector is offline
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Ejection charge is now under control.

Initial amount was .5 grams.

Combined with the caplug retainer, this is too much for any model capable of being launched with such low thrust motors with 4 or 6 second delay times. in other words, the only models these motors will work in are BT-20, BT-50 and lightweight BT-55 and the volume is too small to withstand a .5 gram blast.

As soon as they got the feedback, they reduced them to .3 grams. i do not have a date code cut-in, but the first date is obviously .5 gram (050118).

Contact them if you need to report delay issues and maybe they can figure out what happened. After all, if they made or cut 1000 6 second delays and 1000 4 second delays and they made and shipped 1500 "-4" motors, and 500 "-6" motors then they should be able to determine what happened. if they made exactly the correct amount for the number of motors made and shipped, then they have to do more root-cause/corrective-action.

Quote:
Originally Posted by BEC
I strongly suspect that my B4-4s are mostly mislabeled B4-6s based on data I have in hand. But a couple of them - one from each of the two date codes I have - have been correct.

Since all the ejection charges have been far more than needed I wonder if there was simply too much specified....perhaps thinking based on other Aerotech products for much larger models.

I agree that tolerances of both delay grains and ejection charges need to be looked at.
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  #265  
Old Today, 03:37 PM
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Good--thank you for reporting their ejection charge mass reduction. The original Quest also had motor problems, which to their credit they quickly corrected. My first Quest motor, an A6-4 (black powder, of course) flown in a Quest Pipsqueak, fired its ejection charge as soon as the propellant burned out, at top speed, which resulted in a Kevlar cord "zipper" of its body tube. The motor either lacked a delay charge, or a void along the side of the grain (or maybe a crack) allowed the flame front to instantly rush forward and ignite the ejection charge. I contacted them and submitted a MESS form, and they replaced my motor pack (and also the kit, if memory serves). I used many Quest motors after that, and never had another one fail.
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  #266  
Old Today, 04:23 PM
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Quote:
Originally Posted by Shreadvector
Ejection charge is now under control.

Initial amount was .5 grams.

Combined with the caplug retainer, this is too much for any model capable of being launched with such low thrust motors with 4 or 6 second delay times. in other words, the only models these motors will work in are BT-20, BT-50 and lightweight BT-55 and the volume is too small to withstand a .5 gram blast.

As soon as they got the feedback, they reduced them to .3 grams. i do not have a date code cut-in, but the first date is obviously .5 gram (050118).

Contact them if you need to report delay issues and maybe they can figure out what happened. After all, if they made or cut 1000 6 second delays and 1000 4 second delays and they made and shipped 1500 "-4" motors, and 500 "-6" motors then they should be able to determine what happened. if they made exactly the correct amount for the number of motors made and shipped, then they have to do more root-cause/corrective-action.


I have contacted them....this was before the 5 flights on Saturday and 9 on Sunday. I was actually expecting a call back today but so far it hasnt happened.

Here are the five flights for which I have onboard data via AltimeterThree. For those who are unfamiliar with the device, it carries a three-axis accelerometer as well as a barometric sensor and the delay time is based on accelerometer data. (Id have had two more but the battery connector was not seated fully inside my other AltimeterThree and it shut itself off during the coast phase on those two flights. I probably did that myself as I had pulled and reconnected it during an attempt to troubleshoot a different issue a few months ago.)

Of these five flights one four second and one six second delay was about right. The other three were all long. Visually, just watching from the ground, all the others were long to some extent. I flew one B4-4 on Saturday in an Alpha III that had a perfect flight profile - so I know it can happen. But so far its not the norm.

The B4-6s ejection charge was so violent it ejected the motor in spite of the motor hook (yet, fortunately, didnt rip the motor tube by pulling down the top of the hook). My son found the casing a few minutes later in the grass....and it was bent a few degrees in the middle as if it were soft and flexible when it hit the ground. That surprised me because these generally have seemed to not be any hotter than an Estes motor on the outside at recovery and not as hot as Chinese Quest BP motors.

The Tripoli cert letters for the As and Bs certainly dont show the delays as running significantly long, which is why I suspect mislabeled motors.
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  #267  
Old Today, 07:13 PM
Jerry Irvine's Avatar
Jerry Irvine Jerry Irvine is online now
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Model rocket motors are allowed to go to 200 degrees C. Estes virgin kraft thick paper cannot ever do that and besides BP burns at half the temperature of APCP. The polycarbonate cases Q uses (insert derogatory term I often refer to Aerotech as), are much thinner, have more than 2x the combustion temperature and are so optimised in material usage they actually made the case 0.006-0.01" bigger OD than useable.

Tech Jerry
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