getting a missed part into an otherwise completed rocket

[Nic Rosenau]

Okay, I know that all of you are building the high power rockets, but I'm hoping that you remember enough of your early days in rocketry to help us out here.

I decided that the rocket building area needed a bit of organization and while cleaning up, a little cardboard ring suddenly materialized. I recognized it immediately as the engine block from the Razor that my 6-3/4 year old son built for last month's cancelled launch. (I can also now clearly recall the exact series of events that led to it being left out.) The rocket is now fully assembled (other than this rediscovered part), and it's not going to be easy to get that little ring properly seated inside the engine tube. My boy suggested we ask for help/advice, so I agreed to email this list while he went to bed.

We're attempting to devise a tool (currently working with four chopsticks and a toothpick) to get it down the top of the rocket and push it into place. Does anyone have any advice on a good way to do this. I recall that Stine mentions witnessing the results of this particular error in his Handbook of Model Rocketry, so I'm sure that my boy is not the the first person to do this. We're hoping we can learn from someone else's experience.

My husband noted that there is a small tab on the top of engine clip which he thinks might be sufficient to hold the motor in place without the engine block. Being the mom and also the more fretful of the two of us, I think that if the Custom Rocket Company included an engine block in the design of the Razor, it's necessary for the rocket to launch successfully, so we should get it in there somehow.

If we fail to get the engine block properly and securely installed is the resulting failed launch going to dangerous or just disappointing? Would it be safer if we just scrapped this rocket altogether? My son did build a second rocket this month (the Estes Shuttle Express), so he won't be without a rocket on Saturday if we scrap it -- although he will be quite disappointed.

Thank you so much for your assistance. And my apologies for my long winded manner -- I am aware that verbosity is my curse!

-- Nic Rosenau

[Michael Koppelman]

I think that could work. Since that is the thrust ring, you could slide it in with no epoxy and then put a bunch of epoxy around the top edge, so that it holds firm under thrust. The retainer clip alone will probably not hold the motor in, which means your 'chute might not come out. If all else fails just drill a hole above the motor and put a bolt through it to keep the motor from moving forward.

Good luck!

M.

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[Steve Anderson]

Try a long wood dowel purchased from your local hardware store. Maybe the block can be installed from the nose end of the rocket? Without seeing it this is the best advice I can give.

[Nic Rosenau]

Thanks, Michael and Steve. We were able to place it using a dowel (actually the wooden handle of a fancy bottle opener that was just the right diameter) and then applied glue around the top. The minivan is packed and ready for the drive, so we'll see how it works soon.

-- Nic

[davmach1]

Probably the best advise is to do nothing. You are correct thinking
that the top of the engine hook is enough to hold the motor both
directions. As a matter of fact I have built kits that didn't have a
thrust ring in the MM tube at all just the engine hook. The second
best advise would be to put a few wraps of very narrow tape around the
base of the engine to act as a thrust ring. This has been proven to
work on motors up to O class. Sorry this was a little late but
hopfully it will help you out next time you run into this problem and
trust me you will.

Dave Leininger