 |
 | Home | Contact Us | FAQ | Search & Site Map | Link to Us |
 | Sign In | Join | Other 45 Sites in Network |
| HomeDiscussion Groups General ModelsRailroadsRocketsRadio Controlled Air ModelsHelicoptersLand ModelsWater ModelsModelGeeks.com Contact UsLink To UsSearch & Site Map |
Model Forum / General / Rockets / December 2007opinions on first time mid-power motors?
My Loc/Precision Norad is about done, and I'm thinking about launching it. I don't know what to do for a motor yet though. The engine tube is 29mm, and I'm looking at the aerotech stuff. It might be nice to go with a reloadable that I could use in other rockets as well, but the price difference is quite high. If I were to go with a single use, I still can't derive much difference between the econojet and the standard line. Also, while talking motors, whats the best way to secure them at this level? I read something that said some masking tape around the aft end would do, but if I go reloadable, I'd be afraid that the ejection charge might blow the motor out the back of the rocket. Roadrunner makes some affordable single use. As far as retention, you can take a metal coat hanger and fabricate a hook with a loop at one end. Use a T-nut and a small machine screw to hold it all in place. Hope this helps J > My Loc/Precision Norad is about done, and I'm thinking about launching > it. I don't know what to do for a motor yet though. The engine tube is [quoted text clipped - 8 lines] > would do, but if I go reloadable, I'd be afraid that the ejection charge > might blow the motor out the back of the rocket. > Roadrunner makes some affordable single use. How are those Roadrunner motors? How do they compare to the norm of AT? Ted Novak TRA#5512 IEAS#75 >> Roadrunner makes some affordable single use. > [quoted text clipped - 3 lines] >TRA#5512 >IEAS#75 I've seen a few. They worked fine. I don't remember anything exceptional with them - just like Aerotech. I've seen the "G" in action, pretty cool little motor for the price. > > Roadrunner makes some affordable single use. > [quoted text clipped - 3 lines] > TRA#5512 > IEAS#75 >My Loc/Precision Norad is about done, and I'm thinking about launching >it. I don't know what to do for a motor yet though. The engine tube is [quoted text clipped - 8 lines] >would do, but if I go reloadable, I'd be afraid that the ejection charge >might blow the motor out the back of the rocket. Masking tape works but I suggest that you stick with positive motor retention. Types that I used successfully are the Kaplow clip, Acme, & PML. Rocketry Planet and Info Central have a decent amount of information and pictures. Loc makes a 24-29mm adaptor that works well. I is useful some of the smaller 24mm motors. Make sure that you have a thrust ring or some way to prevent the motor for flying up through the rocket. Phil J., If you expect to be in the hobby for a while, the reloadables get inexpensive rather quickly. The Aerotech "Reloadable Motor System 29/40-120" is capable of being reloaded with motors from E to G range is about $70 for the case, and will be paid for in about a half dozen launches. For example, F50's (single use) are $19 at HobbyLinc, and F52's (reloads) are $10. In seven launches, you have paid for the case and then the case just keeps getting cheaper. The G64 and G71 reloads are $10.70 each, and the equivalent single use are between $20 and $26. I really like building the motors with reloads. It finishes my ownership of the rocket, and you gain a lot of experience for when you go into the high power. I have a 29mm case, two 24mm cases, and an 18mm case in the hobby sizes (and a nice range of 38mm high power cases). Use some sort of clip to hold it in. Even a wood screw throught the aft center ring with a big washer to overlap the motor lip is better than tape, especially for a reloadable. I'd use a blind nut or tee nut on the back, myself, but you have to do that before the motor mount is glued in. It eliminates the possibility of pulling the wood threads apart when the big ejection charge goes off. You could even use two or three if you want. Lastly, the econojets are just a marketing thing. The F20 has a total impulse of about 60Ns, opposed to a full F (like the F25) of 80Ns. Still, RockSim estimates a rocket the size of the Norad to reach 670 feet on an F20 and leave a 6 foot rod at a respectable and safe 46 feet/second. Choice is yours.  SignatureTom Koszuta Western New York Sailplane and Electric Flyers Buffalo, NY > My Loc/Precision Norad is about done, and I'm thinking about launching it. > I don't know what to do for a motor yet though. The engine tube is 29mm, [quoted text clipped - 8 lines] > would do, but if I go reloadable, I'd be afraid that the ejection charge > might blow the motor out the back of the rocket. > J., > [quoted text clipped - 45 lines] > > - Show quoted text - Econojets are a shipping thing. They have 30 grams of propellant so they can be shipped USPS by apoproved shippers (without HAZMAT fees like UPS). Small clarification below. > J., > [quoted text clipped - 19 lines] > big ejection charge goes off. You could even use two or three if you > want. Actually you just have to put the nut in before the aft centering ring is glued in, not before the motor mount is glued in. > Lastly, the econojets are just a marketing thing. The F20 has a total > impulse of about 60Ns, opposed to a full F (like the F25) of 80Ns. Still, [quoted text clipped - 14 lines] >> would do, but if I go reloadable, I'd be afraid that the ejection charge >> might blow the motor out the back of the rocket. |
Reply to this Message |
 Sign In
 Join
 My Latest Posts My Monitored Threads My Blog My Photo Gallery My Profile My Homepage Start New Thread Enable EMail Alerts Rate this Thread
|
©2008 Advenet LLC Privacy Policy - Terms of Use
This website includes both content owned or controlled by Advenet as well as content owned or controlled by third parties.