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First MPR with an NCR Laser Hawk

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TangoJuliet

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After 25+ years out of model rocketry, I'm jumping back in with both feet and building a North Coast Rocketry "Laser Hawk" that I bought from Apogee. I was fairly active in LPR in my teens and even competed in some NAR competitions. When I got out as a young adult re-loads were just coming onto the scene and I have no experience with them.

The Laser Hawk is designed for a 29mm motor (F-G) single-use motors, but there is no retainer ring or clip. I'm considering buying a re-load casing. I've looked at some of the info regarding Aerotech re-loadable motors on the Apogee website, and I understand that the aft closer acts as the stop, but what retains the motor in the engine tube at ejection? And... they're listed as 29/60, 29/100, 29/120, and 29/40-120, etc. I assume the second set of numbers is the length of the grain(s) that the case will hold. So does that mean if I bought the 29/40-120 I have more re-load options than just the 29/60 or 29/100? Is my limiting factor the length of my motor tube in the rocket? I'm so confused :confused2:. Help me to understand, please.
 

dhbarr

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After 25+ years out of model rocketry, I'm jumping back in with both feet and building a North Coast Rocketry "Laser Hawk" that I bought from Apogee. I was fairly active in LPR in my teens and even competed in some NAR competitions. When I got out as a young adult re-loads were just coming onto the scene and I have no experience with them.

The Laser Hawk is designed for a 29mm motor (F-G) single-use motors, but there is no retainer ring or clip. I'm considering buying a re-load casing. I've looked at some of the info regarding Aerotech re-loadable motors on the Apogee website, and I understand that the aft closer acts as the stop, but what retains the motor in the engine tube at ejection? And... they're listed as 29/60, 29/100, 29/120, and 29/40-120, etc. I assume the second set of numbers is the length of the grain(s) that the case will hold. So does that mean if I bought the 29/40-120 I have more re-load options than just the 29/60 or 29/100? Is my limiting factor the length of my motor tube in the rocket? I'm so confused :confused2:. Help me to understand, please.
29/40-120 is a hobby case with lots of loads.
29/60 & 29/100 are mid/high casings with completely different loads.

They are entirely incompatible. If you are just getting started w/ reloads, 40-120 is a great place to start.

The motor casing can be retained with a hook or screw type retainer, or almost any other method ( e.g. tape, tailcone )
 

TangoJuliet

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Thanks. I think I saw something about a screw-type retainer ring that can be JB welded onto the motor tube. I'll look a little deeper into that. Tape just doesn't sound like the best option for these larger, and more expensive motors.
 

dhbarr

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Thanks. I think I saw something about a screw-type retainer ring that can be JB welded onto the motor tube. I'll look a little deeper into that. Tape just doesn't sound like the best option for these larger, and more expensive motors.
Estes has a plastic one, Aerotech's is the least expensive aluminum one, Aeropack is well-regarded AFAIK.
 

Bat-mite

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Aeropack's 29mm Type L retainer is recommended by Apogee for this rocket.
 

samb

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Tape ain't pretty. Tape ain't sexy. Tape just works. Is there any guidance in your Laser Hawks instructions about retention ? One thing I will add is when I came back to the hobby, my best resource for learning about composite motors and reloads was my local rocket buddies. If that option is available to you I would suggest seeking out a club near you. TRF is a good forum with lots of knowledgeable posters. But nothing beats hands-on training with someone who's done it before IMO.
 

samb

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Didn't see this mentioned yet but the reloads for 29/40-120 case, along with 24/40 and 18/20 are referred to by Aerotech as HobbyLine because they can be sold in hobby shops and flown without FAA clearance or national hobby rocketry organization certification. The other cases you listed are used for high power reloads that are flown with the proper certifications and airspace clearance. The 29/60 is an oddball that up till now hasn't had many reloads available. Aerotech has been saying this will change for some time now
The number to the left of the slash is the diameter of the case in millimeters. The number(s) to the right is the maximum total impulse for the case. The 29/40-120 has a range because you can buy reloads from E to G making it a very popular case.
 
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TangoJuliet

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Unfortunately, there isn't a club local to me, I've already checked. The nearest one is at least a couple hours away in the Florida panhandle. The next is 3+ near Birmingham.

There is no mention at all about motor retention in the instruction manual. Besides Apogee, who else might carry the Aeropak retainers? The local HTUSA has mostly Estes kits and single use motors, and some Aerotech motors, but not in 29mm. I'm pretty sure I've left enough of the motor mount tube exposed to add a retainer ring. It's actually more exposed than it's supposed to be. Not by much, but the mount slipped during the epoxy cure and I didn't catch it in time. No biggy, but I'll need to notch the fin roots to get the right fit again when I mount them.
 

crossfire

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Most all rocketry vendors will carry aeropack retainers. Just check out their web site for a dealer near you. Or you can order right from them.
 

dhbarr

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From pg. 7, Flight Preparations:

"
□ Install the motor into the motor mount until all but the
last ½” in exposed. Endure the motor is snug in the
motor tube, and that it will not move forward or aft.
Using ¾’ wide masking tape, wrap the aft end of the
motor and the motor tube to secure the motor in place.
It is critical that the motor be firmly retained. If the
motor is loose, it may blow out at ejection, causing the
model to crash.
"
 
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TangoJuliet

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I just realized, I'm missing a page or two from the instructions. :sad: The page(s) that refers to attaching the "booster" tubes.
 
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