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  #21  
Old 02-23-2020, 02:11 PM
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Quote:
Originally Posted by LeeR
I would be intetested in whether anyone has more information on the MRC Tracker motors.

Don't hold me to this, but I think I remember reading that some folks said there was no difference performance wise in the Trackers and the regular motors. I also think I remember some other folks arguing they produced more smoke. It makes me think that they at least eventually just slapped the label on some regular motors and threw them in the packaging with the fake nozzles. I only had the regular motors. They had a dirty yellow/brown smoke and seemed weaker to me than the equivalent Estes motors.
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  #22  
Old 02-23-2020, 02:38 PM
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Quote:
Originally Posted by tbzep
Don't hold me to this, but I think I remember reading that some folks said there was no difference performance wise in the Trackers and the regular motors. I also think I remember some other folks arguing they produced more smoke. It makes me think that they at least eventually just slapped the label on some regular motors and threw them in the packaging with the fake nozzles. I only had the regular motors. They had a dirty yellow/brown smoke and seemed weaker to me than the equivalent Estes motors.


Thanks! I forgot to mention that I’ll try a few of these next time I go out, fly the equivalent Estes motors for comparison, and I’ll takes some pictures.
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  #23  
Old 02-23-2020, 04:57 PM
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Quote:
Originally Posted by LeeR
I would be intetested in whether anyone has more information on the MRC Tracker motors. I bought about 12 packs on clearance at our Hobby Town around 1990-91, for about $1. The store tag shows $3.65 for a pack of B6-4s, dated 8-28-89. I also have A8-3, B4-4, and C6-5 packs. I have not found much information in my searches.

I remember using a few, and they worked perfectly, but not much recollection beyond that (that was ~30 years ago!).

I thought there were no igniters, then noticed two were taped onto one of the motors. To use, the leads were inserted thru the tiny hole in the black plastic “fake nozzle”, the tip dropped into the motor, and then black nozzle was pressed into a small recess in the motor’s nozzle to secure the igniter, and finally the red plastic cap snapped into the black nozzle to hold the leads firmly in place, and separated. Note the glass beads on the igniter hold them separated, and allow spreading of the ends of the leads without concern for the leads near the tip. Quite ingenious.


Since they are made in Germany and the nozzles look just like the quest Weco motors, I think they are Weco. The German labeling may be under the paper. Are the casings a little short?
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  #24  
Old 02-23-2020, 08:57 PM
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...and slightly smaller in diameter. The few Weco-made Quest motors I've had have all been very loose fits in motor mounts.
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  #25  
Old 02-24-2020, 07:19 AM
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Quote:
Originally Posted by BEC
...and slightly smaller in diameter. The few Weco-made Quest motors I've had have all been very loose fits in motor mounts.

Yes, they were so loose that the ejection gases leaked by and burned the puny blue motor tubes of our schools' E2X rockets. Too bad, because the delay was perfect for that rocket. A8-3 is way too short, and A8-5 a little too long.
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Old 02-24-2020, 05:04 PM
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Quote:
Originally Posted by Gus
Thanks, Bob!

Really well told! Thanks.

I believe the German motor manufacturer was Weco.

One more thing. Bill told me several times what an impediment shipping costs were to bringing in the Chinese motors. Even a huge shipment of motors took up just a tiny fraction of a standard shipping container. It wasn't possible to share a container with non-rocketry items and the fireworks folks were so huge they had no need to share containers. So Quest had to pay for a whole container even though using just a small part of it. I can't recall what percentage of the actual cost of bringing in a pack of motors was due to shipping but I know it was huge.

Steve


What he said Bob!
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  #27  
Old 02-24-2020, 06:23 PM
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I did a test fit of one of MPC tracker motors in a rocket with an engine hook. It seemed a bit short so I measured it. It was 69mm long. My Estes motors measure 70mm, so not a huge difference, but noticeable.

The diameter of the motors was interesting. The MPC was 18mm, the Estes 17.6mm, both fit fine in the test rocket.

The biggest difference was casing thickness. I did not measure, but I did take a picture. The Tracker had a much thinner casing. The Estes motor is a B6-6 manufactured in 2019.
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  #28  
Old 02-25-2020, 07:57 AM
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Quote:
Originally Posted by LeeR
I did a test fit of one of MPC tracker motors in a rocket with an engine hook. It seemed a bit short so I measured it. It was 69mm long. My Estes motors measure 70mm, so not a huge difference, but noticeable.

The diameter of the motors was interesting. The MPC was 18mm, the Estes 17.6mm, both fit fine in the test rocket.

The biggest difference was casing thickness. I did not measure, but I did take a picture. The Tracker had a much thinner casing. The Estes motor is a B6-6 manufactured in 2019.

Was the 18mm thickness including the "Tracker" wrap? There is usually some naked motor at the very end. Measure the diameter there and see what it is.
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  #29  
Old 02-25-2020, 10:53 AM
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Quote:
Originally Posted by tbzep
Was the 18mm thickness including the "Tracker" wrap? There is usually some naked motor at the very end. Measure the diameter there and see what it is.


Yes, the diameter was measured at the middle, over the wrap. But I did not measure the end, where there was bare casing showing. So I remeasured everything this morning.

My digital calipers burn thru button cell batteries in about 6 months, so my measurements are with a good old analog dial caliper. I’ll list measurements in inches, and converted to metric in (mm). I got slightly smaller reading today on Tracker. I may have not measured accurately the other day. I measured in several locations along the wrapper, and today’s measurement was consistent.

I also remeasured the Estes motor, since I had randomly grabbed a motor from a container of 5-6 B6-6 motors the other day. Turns out the measurement was different, and I measured another, which was slightly smaller — must have been the one I previously measured. Several more motors measured show variations of .005” or so, which is certainly to be expected on wound paper casings, vs. a machined or molded part. Listed below is a median value for the Estes motors. This is also very close to the measurement on a 2008 motor I measured.

TRACKER diameter

with wrapper .699” (17.8mm)

w/o wrapper .677” (17.2mm)

ESTES diameter

.695” (17.7mm)

Conclusion: These motors from MRC and Estes fit equally well into a rocket of mine with a BT-20 motor tube.
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  #30  
Old 02-25-2020, 11:24 AM
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Quote:
Originally Posted by LeeR

TRACKER diameter

with wrapper .699” (17.8mm)

w/o wrapper .677” (17.2mm)

ESTES diameter

.695” (17.7mm)

Conclusion: These motors from MRC and Estes fit equally well into a rocket of mine with a BT-20 motor tube.

That fits with the standard MRC motor and the Quest labeled ones being loose. I guess Quest used thinner paper. The tracker had the same casing as the standard MRC motor with the nice rounded end, plus the adhesive wrap. I still have a few standard ones around the house somewhere.
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