Madcow Rocketry AQM-37A JayHawk Questions

[mg444]

Hello -

I'm new to this forum, but not new to rocketry. I've been building rockets off and on for 20 years or so, but this rocket (AQM-37A) is my second mid-power rocket. My first was a Lance Delta by North Coast Rocketry.

Anyways, I have some questions about this Madcow kit. Parts seem to be very good quality but as hard as I try, I don't understand a few things in the instructions (mainly with the nose cone) but will get to that in a bit. First question is the engine mount, and lack of engine retainer. I don't understand the "building a thrust ring with masking tape" part. I have a couple Aerotech composite motors (single use - F26-6FJ) suggested for this kit. Do I need to build a thrust ring? Or, on my Aerotech composite motor, is the thrust ring the black plastic lip around the aft end of the motor? If so, I understand how the motor stays in place while the rocket goes up, but when the parachute ejects, what holds the motor in place? I'm confused...

Second, the nose cone. My plastic nose cone is a lot longer than the pics show. Basically, I understand where part of the nose cone that gets painted black, but there is two rings underneath that which DO NOT fit in the rocket tube body. When I place the nose cone in the tube, it stops at the first ring, maybe a 1.25 inches or so above where you would tie the parachute. Do I need to sand these plastic rings down so my nose cone sits properly in the tube? Or do I need to do something different? Or am I missing the point (which is very possible).

Sorry for the dumb questions... I'm new to mid-power rocketry so I could use some help.

Thanks, Mike

 

[jd2cylman]

Hello -

I'm new to this forum, but not new to rocketry. I've been building rockets off and on for 20 years or so, but this rocket (AQM-37A) is my second mid-power rocket. My first was a Lance Delta by North Coast Rocketry.

Anyways, I have some questions about this Madcow kit. Parts seem to be very good quality but as hard as I try, I don't understand a few things in the instructions (mainly with the nose cone) but will get to that in a bit. First question is the engine mount, and lack of engine retainer. I don't understand the "building a thrust ring with masking tape" part. I have a couple Aerotech composite motors (single use - F26-6FJ) suggested for this kit. Do I need to build a thrust ring? Or, on my Aerotech composite motor, is the thrust ring the black plastic lip around the aft end of the motor? Yes. If so, I understand how the motor stays in place while the rocket goes up, but when the parachute ejects, what holds the motor in place? You'll need to install a Aero Pack Retainer or something similar. Or you can make Kaplow Clips. Google those.. I'm confused... It's OK

Second, the nose cone. My plastic nose cone is a lot longer than the pics show. Basically, I understand where part of the nose cone that gets painted black, but there is two rings underneath that which DO NOT fit in the rocket tube body. When I place the nose cone in the tube, it stops at the first ring, maybe a 1.25 inches or so above where you would tie the parachute. Do I need to sand these plastic rings down so my nose cone sits properly in the tube? Yes, carefully. Or do I need to do something different? Or am I missing the point (which is very possible).

Sorry for the dumb questions... I'm new to mid-power rocketry so I could use some help.

Thanks, Mike

Added bold responses to your questions. As far as motor retainers, there are lots of options. Aero Pack is just one. There is also slim line, Aerotech offers them, as does Estes.
Most new single use motors now have the thrust ring cast in. Earlier ones did not, those you had to add a tape ring. Another option would be to friction fit the motor. Basically just wraps of masking tape spiraled around the motor to keep it from kicking out. Browse around the forum some and you'll find most of the retainers used somewhere. I've got the kit down in the basement, just haven't got to it yet.
Hope this helps a little.

 

[dhbarr]

Question 1, you've got the right idea. Estes motors need the built-up thrustring.

Friction fit is a wrap or two of masking tape around the body of the motor. Add or remove a small bit of tape to get a tight fit.

You can also run a wrap of tape around the aft end, with enough overlap to catch the ring.

There are also a variety of screw-on motor retention methods. I'm not familiar with your particular kit, so I couldn't say further.

 

[rstaff3]

I forget whether I added any extra nose weight to compensate for the rear-mounted hardware.

 

[mg444]

Thanks for the tips everyone. I have everything figured out and I'm in the process of painting now. I will post pics when finished.

-Mike