Engine Mount

[bkent1@mac.com]

All,

Just had a 18 mm estes engine mount blow out on me and I want to replace it. Had a few questions:

1. Is their any way to put in a retention system with a retainer ring instead of the estes engine mount? Its a BT-60HE body tube (Red Max). I'm guessing this can't be done but wanted to check.

2. Should I go with a 24 mm engine mount so I can try and use D & E engines? I'm guessing that sucker would fly to 700-800 feet. If I do that, is there an adapter that you can slide in and out to use B&C engines (for my daughters).

3. Final question is around shock cords. I'm using 100lb kevlar thread and have been looping it around the estes engine mount. Any better way you know to do it?

Thanks,

Bill Kent

[Doug Sams]

Just had a 18 mm estes engine mount blow out on me and I want to replace it. Had a few questions:

1. Is their any way to put in a retention system with a retainer ring instead of the estes engine mount? Its a BT-60HE body tube (Red Max). I'm guessing this can't be done but wanted to check. There are many ways to add motor retention, but the standard motor hook works well, and there's no ring to lose ;) You can always add a wrap of tape around the motor and hook to keep the motor from slipping past it.

2. Should I go with a 24 mm engine mount so I can try and use D & E engines? I'm guessing that sucker would fly to 700-800 feet. If I do that, is there an adapter that you can slide in and out to use B&C engines (for my daughters). You can make an 18mm adaptor, or use spent 24mm cases as throwaway adaptors.

For the 24mm mount, leave out the forward motor block and use tape thrust rings around the aft end of the motor. This solves the problem of dealing with unequal length motors such as the D12 and E9 (and F32, G37, G55, et al) . Three wraps of 1/4" or 1/2" wide masking tape around the nozzle end of the motor makes a sturdy thrust ring.

3. Final question is around shock cords. I'm using 100lb kevlar thread and have been looping it around the estes engine mount. Any better way you know to do it? I use kevlar, and like you, I loop it around the motor tube behind the forward centering ring and anchor it with a bit of glue.

Doug

.

[Rocket Doctor]

All,

Just had a 18 mm estes engine mount blow out on me and I want to replace it. Had a few questions:

1. Is their any way to put in a retention system with a retainer ring instead of the estes engine mount? Its a BT-60HE body tube (Red Max). I'm guessing this can't be done but wanted to check.

2. Should I go with a 24 mm engine mount so I can try and use D & E engines? I'm guessing that sucker would fly to 700-800 feet. If I do that, is there an adapter that you can slide in and out to use B&C engines (for my daughters).

3. Final question is around shock cords. I'm using 100lb kevlar thread and have been looping it around the estes engine mount. Any better way you know to do it?

Thanks,

Bill Kent

You could get plywood adapter rings instead of the cardboard ones, and, use a beefed up motor tube instead of the blue one.

You could go to 24 mm, make sure it's blanced out correctly. You can also make a removable engine mount for 18mm to 24mm.

You would use a 18mm engine mount tube, with the engine hook as usual, then, use two 2050 adapter rings, they should be the green ones. the removable engine mount would fit inside the 24mm motor tube as if it were a 24mm motor. Estes use to sell these adapter kits years ago.

BMS might sell them.

Good luck with your project.

I haven't used Kevlar at all, there should be others out there with more experience whit that.

[bkent1@mac.com]

Thanks for al the input.

Appreciate it.

BK

[Rocket Doctor]

Thanks for al the input.

Appreciate it.

BK

Check out Balsa Machining Service at the following

http://www.balsamachining.com/CATALOG.htm

I don't know if Semroc has the motor adapter kits, but, you can take a look

WWW.SEMROC.COM

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In the 1992 Estes catalog on page 59, under engine mounts is the following item

Special Purpose Quick-Change Conversion Mount- From "D" Engines to Regular Engines

Product #3154

description EM-2050