4" Madcow Frenzy Motor Mount Question

[TMJ]

I've dry fitted all of the parts, prior to getting the build going, however. I'm confused about the 54mm motor mount tube. It's just a tube. No retaining rings, no 'nothing' on either end of the tube. Madcow instructions say nothing about what 'locks' the motor firmly in place forward/aft? I also do not know just what motor I intend to use, at this point. All I can say is that I'll be going for a level 1 certification. I cannot start on the motor mount until I know just how the motor mount is supposed to work, and what to do to keep the motor in place during flight. The instructions are 'obviously' geared towards those who already know what to do. I'm 'obviously' not one of those persons, not yet! :confused2:
Help, please!

 

[crossfire]

Hi
Most High power motors will have thrust ring on the motor. This will keep the motor from going up through the motor mount tube during the motor burn. What you will need is some type of motor retainer to keep motor from sliding out of the back end of the rocket. I have used Aeropak motor retainers for years. I think MC sells them on their site. There are other brands that also work very well. Just call or email Mike at MC and he will help you out.

 

[TMJ]

Many thanks! Another piece of the puzzle solved! I was curious about that. Any suggestions as to what motor(s) I should seek for using as level 1 certification via this 4" Frenzy? Motors have me stumped, also...

 

[rharshberger]

Many thanks! Another piece of the puzzle solved! I was curious about that. Any suggestions as to what motor(s) I should seek for using as level 1 certification via this 4" Frenzy? Motors have me stumped, also...

What motor brand(s) does your launch site vendor carry? Usually its best to buy what your vendor carries if possible, as they will also carry the casings for the re-loadable motor if thats what you choose. Depending on how heavy you build the rocket, what your launch site looks like, wind, all can help determine what motor is best for that field, rocket, day combination.

 

[TMJ]

What motor brand(s) does your launch site vendor carry? Usually its best to buy what your vendor carries if possible, as they will also carry the casings for the re-loadable motor if thats what you choose. Depending on how heavy you build the rocket, what your launch site looks like, wind, all can help determine what motor is best for that field, rocket, day combination.

***
I haven't gotten to that point, yet. There are three clubs close to me, but I've not yet contacted any of them. At 'this' stage, I'm simply looking to accomplish a solid/functional build. After the build, and joining NAR, and or Tripoly I'll then start looking into the clubs, launch sites, etc., and make a choice.

 

[Banzai88]

I suggest that you start here with watching these videos first, as the info applies to most all cardboard and ply kits:


https://youtu.be/5w0LJ7Hw72w

Watch the whole series, it's worth it. It'll help you make some of the decisions that the kit requires you make BEFORE joining parts with glue. No reason NOT to contact the clubs and visit beforehand, folks there will help you out LONG before you're ready to fly. :2:

 

[DavidMcCann]

It's a 54mm mount, however you can 'adapt down'. if you get an aeropac retainer, you can use their 54-38 adaptor which just slides in and holds a 38mm motor. That's how I'd get my L1.

Motors- they make single use in this size. Personally I'd rather use reloadable hardware. There are three major manufacturers. Aerotech, CTI, and Loki.

Chris has all three- https://www.csrocketry.com

Tim carries AT and CTI- https://www.wildmanrocketry.com (38mm special set- https://www.wildmanrocketry.com/ProductDetail.aspx?product=7128)

both are good places to shop.

I'd either get the 38mm special from AT and go L1 on an I600R and then L2 on a J500G (if you go that way you can do it with just a 720 case )

or get a Loki 38/480 and 38/740 case. The benefit to the Loki system is most of the 480 loads ship haz mat free (a ~$30 surcharge on many larger motor shipments, and all CTI loads.


AT and CTI make some 54mm L1 loads if you want to go that way, but I prefer L2 loads in that size. The 38 are a bit more cost effective.

 

[Tim51]

Good luck with the certification flight. The 4" Frenzy looks a good choice. Are you going to do a build thread?

(Ah - just found your other thread five mins after posting this!)

 

[Exactimator]

Nice choice on your first HPR.

For help with motors, go to thrustcurve.org and use the motor guide. Put in your rocket diameter, weight, and mmt size and it'll give you a list of motors that will work, including max altitudes and speeds.

Your rocket will probably weigh somewhere around 5 lbs built and ready to fly without the motor. You'll need a high initial thrust H or I to get it off the pad with enough speed. For example, a 38 mm CTI H225 white thunder will get it up to about 1,200 feet. A nice easy flight to see from the ground.

When you contact Mike at Madcow about your retainer, also ask him about the Aeropak 54 to 38 mm adapter. That will give you a much large assortment of motors to choose from. And you might notice that 38mm motors have a higher initial thrust than their 54mm equivalents (it has to do with the grain geometry).

Good luck with your cert!

 

[alex_car763]

***
I haven't gotten to that point, yet. There are three clubs close to me, but I've not yet contacted any of them. At 'this' stage, I'm simply looking to accomplish a solid/functional build. After the build, and joining NAR, and or Tripoly I'll then start looking into the clubs, launch sites, etc., and make a choice.

I would tap resources in your local clubs. Most are more than happy to help and can offer support and suggestions that can help you from making choices that later or with experience or those inputs you would not have made. Up to you of course.

 

[nmartin]

im using the aerotech mount for cardboard. It's under the blue tape to keep the rocketpoxy off of it when I install the rear centering ring. I buy the motor mount at the same time as the rocket. I didn't buy one with my first high power and had the same question.

 

[BDB]

I agree with everyone who mentioned the adapter from 54 to 38 mm. As for motors, go with whatever brand your local vendor carries. Or do what I did with a large L1 kit like yours and buy a Loki 38/240 and/or 38/480 case. That way you can fly some great reloads hazmat-free.

Just start running simulations in OpenRocket. For a single deploy L1 flight, you want your launch to be at least 50 ft/sec off the rail, and I suggest trying to keep it around or below 2k ft that way you can easily see everything.

 

[Nathan]

Aero Pack motor retainers are extremely nice but are not cheap. If you want a less expensive option it is easy to build a very functional homemade motor retainer: https://www.rocketryforum.com/showthread.php?11902-Homemade-Motor-Retainers