Retaining F size Engine's

[Commanche3]

I just received my first F sized engine's my question is on my Super Bandit the motor mount doesn't have a thrust ring do you just friction mount the engine?


Thanks
Kevin

[Shreadvector]

What brand of F motor (or "engine" - there are no moving parts, so it's really a motor)?

Aerotech motors come with a molded thrust ring on the nozzle end of the newest single use motors OR they have a cardboard ring that you epoxy onto the nozzle end of the casing of semi-new motors. Older motors had no ring and they expected you to:
a) install in an Aerotech kit with appropriate thrust ring and spacer and metal motor clip.
or
b) install using a thrust ring formed by wrapping masking tape aroound the ozzle end of the casing so that it butts up against the aft end of the body tube. Then retain with more masking tape overlapping the butt joint OR use a metal clip OR use another "positive motor retention" method. Do a web search for that term on the web or on The Rocketry Forum.

[Bazookadale]

Follow Fred's advice above - avoid friction fitting a composte motor because they get hot enough to melt some types of tape which would bond the motor inside the tube.

[tbzep]

Even with friction fit, it would be better to add a thrust ring of some type for peace of mind. You will still need use a retaining clip or friction fit for motor retention during ejection. However, you can't use just any brand of masking tape. Like they said, cheap masking tape will melt and form a really strong bond. You might even go to the point of destroying the motor mount tube to remove the spent motor.

After all these warnings, you can still friction fit with tape for motor retention at ejection with 100% success. Go to the automotive section of your local dept. store or go to an auto parts store and buy 3M Scotch brand masking tape. This stuff won't gum up under heat under normal conditions. It's thicker so fewer rounds will be needed, but it's more expensive. Stay away from the cheap Manco or any off-brand stuff. The Manco mess will sometimes get gooey and stick a small Estes motor, so you can imagine what would happen with a larger F burning three times as long.

[Initiator001]

Kevin,

I have a Hawk's Hobby Super bandit kit which is built and awaiting a time when I can finish painting it.

The Super Bandit uses a removable/changable motor mount much like large Semroc models. The motor mount tube is only 2" long.

I plan on flying the HH SB on AeroTech Econojet motors which have either molded thrust rings or a glue-on thrust ring. That will take care of the boost pahse of the flight.

In order to retain the motor in the mount, I will be wrapping a tape ring around the forward end of the motor where it exits the front of the motor mount tube. This will keep the motor from ejecting out of the mount. This may seem a little strange/different but it has worked for me in the past. :)

Post some pictures when you have finished your Super Bandit.

Bob

[Commanche3]

Initiator001 my motor mount's are both 5". I bought both 24mm and 29mm and there both the same length.

[tbzep]

In order to retain the motor in the mount, I will be wrapping a tape ring around the forward end of the motor where it exits the front of the motor mount tube. This will keep the motor from ejecting out of the mount. This may seem a little strange/different but it has worked for me in the past. :)



Not strange at all. It's a great solution for a short removable mount. :)

[Doug Sams]

In order to retain the motor in the mount, I will be wrapping a tape ring around the forward end of the motor where it exits the front of the motor mount tube. This will keep the motor from ejecting out of the mount. Where possible, I use this technique on the 2nd stage of BP stagers. I cut the 2nd stage motor tube short to allow for it. The tape ring forces the 2nd stage to separate with the 2nd stage motor thus avoiding fried boosters.

Doug

[Initiator001]

Initiator001 my motor mount's are both 5". I bought both 24mm and 29mm and there both the same length.

Kevin,

Hmm, I guess Hawk's Hobby changed the 29mm motor mount for the Super Bandit.

My SB has the 5" motor tube on the 24mm mount but my 29mm mount has a 3 1/2" long piece of motor tube. I bought the SB and extra 29mm mount at NARAM-49 this past summer.

Which motor mount do you plan to use for your first flight?

Bob