Friction Fit: 18mm versus 13mm

[mh9162013]

I'm thinking about building my first friction fit rocket that uses 13mm engines (I've previously used an engine hook or retainer ring). I assume that the process of friction fitting a mini motor (Estes BP) is pretty much the same as the 18mm engine (Estes BP). I also assume there aren't any different approaches when friction fitting smaller engines, but maybe I'm wrong?

For example, do some of you feel like you want your 13mm engine to feel "tighter" inside your rocket compared to an 18mm engine that's been friction fitted?

Or do any of you think it's easier/harder to get a 13mm friction fitted motor stuck in the rocket?

Basically, just curious as to whether friction fitting a 13mm motor is any different than an 18mm motor.

 

[waltr]

Not much different than 18mm motors. Just needs to be tight enough not to eject but still be removed.

 

[goose_in_co]

Basically, just curious as to whether friction fitting a 13mm motor is any different than an 18mm motor.

No difference in my opinion, other than you will need less tape.
Basically the engine has to have a tighter fit than the nose cone so that the ejection charge pressure will blow off the nose cone and the wadding and recovery system because that is the easier escape of pressure than your friction fit motor.

 

[BEC]

Even friction fitting 6mm motors (MicroMaxx) is pretty much the same except for the amount of tape you use….

 

[mh9162013]

Thanks for the replies everyone!

 

[BABAR]

YMMV, however I find that Immediately AFTER the flight removing the motor is easier than waiting for it to cool or get home. I also pop them in a ziplock for the trip home(unless I can let them cool and there is a nearby trash receptacle.)

Keeps them from smelling up the car.

 

[mh9162013]

I also pop them in a ziplock for the trip home

Me too.

After a launch, I set them on the ground (making sure there's no fire risk) and let them cool, before putting them in the plastic bag.

 

[PDawg]

I've friction fit 18mm, 24mm, and 29mm motors, didn't notice anything different about any size.