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jimmydrummer

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Hey guys and gals!

I'm Jim and I'm new here. I'm a long time rocketeer, and I'm looking to graduate from C-D engine kit builds to my own large MPR custom builds.

What do you suggest as far as getting started? I'm basing my design on a 6ft tall, 6 inch diameter cardboard tube.

What material is best for fins?

Where can I get engines larger than D?

What formulas are available for thrust/weight ratios to make sure the engines I buy will lift my rocket?

Have any of you build models that film launches with onboard camera systems?

All help would be greatly appreciated! I'd love for you all to introduce yourselves, we can be pals!

-Jim
 
I think for your first MPR, although that is where I am myself, you might want to look into a kit. It would have instructions on what adhesives, techniques, etc you should be using. Sorry to break this to you, but that tube with some fins and a basic nosecone would take a large H engine(HPR) to get it safely off the ground. Look for one that is more in the 1.5 inch to 4 diameter range for MPR. For fins, you would want basswood or thin plywood, or maybe fiberglass. You are going to want to be through the wall fin mounting, not surface mounting. You will need to slot, or cut small slits in your body tube so the fins will stay on. For engines, you might want to look on hobbylinc.com. They have great prices. If you are planing on doing very many launches, you may want to look into a reload casing. They cut costs and give you a wider variety of engines you can use. To see if your rocket will take off safely, you can use openrocket. It lets you simulate how your rocket will perform on different engines. I never have mounted a camera on a rocket, but youtube has many, many videos of them. Finally, I'm sorry if I insult anyone, but based on what I've seen, there aren't too many 'gals' on this forum. Welcome to the forum!
 
iirc 'mid-power' rockets can weigh up to 1500g with motor installed...and about the biggest motor one can get w/o being hpr certified is a G80. I too suggest that you start with something a tad smaller than a 6" dia. tube.
rex
 
Thanks guys!

I was worried about certs and registration with a rocket that size. Luckily, I've got smaller tubes. I might build the large one anyway and leave the engine compartment open until I'm certified and registered.

Yinz guys are awesome!
 
Welcome Jim,

If you've done a number of D kits and scratch built rockets, moving up to E- G power isn't that big of step. It takes stiffer body tubes then Estes tubes, basswood or plywood fins instead of balsa, and usually rails instead of rods for launching.

Building a 6" rocket for use with MPR is really a pretty limited rocket. It has to be less then 3 lbs "on the pad" OTP and then a G64W will get you 400 to 450 ft. It would really fly much better on 38mm or 54mm I - K motors. I would pack that tube away in a safe place and pull it out for that L1 or L2 cert rocket.

I would recommend a Binder Design (Thug, Excel Jr., Aspire, etc) or Loc Precision (Aura, Lil' Nuke, Onyx, etc) 29mm kits just to name a few. These will fly great on E-G motors and give you a great feel for how the larger rockets are constructed and assembled. The methods used with these will follow on to L1 and L2 rockets.

Keep checking back here, I'm sure the following posts will list lots more kits available. There are literally hundreds of MPR rockets from dozens of manufactures to chose from.

If you plan to fly a lot MPR, I highly recommend the 24/40 and 29/40-120 Aerotech Hobbyline Reloadable Motor System (RMS) motor casings. Dr. Rocket and Rouse-Tech are licensed to produce the same motors under their own names. Three are more then 20 different reloads available for the 24/40 and 29/40-120 cases in D - G sizes.

Keep asking questions and we'll keep supplying the answers. :D
 
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