RMS-RC™ 18/20 Motor Case

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dhbarr

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Got one of these hanging around? At the very least I'd like you to weigh it & measure it, but a more permanent arrangement may be preferred :)

Note that my intent is to compare / contrast with an 18/20 and the solid plugged forward closure as well as an epoxied standard 18/20 forward closure.
 

KevinM

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I'm not looking to part with my 18/20, so I went for the measurement option.

My standard case weighs in at 11.9g. (Case, fwd closure, aft closure.) Case with a JB-weld plugged fwd closure comes in at 12.4g.

I wasn't aware there was a solid plugged forward closure for this case.
 

rharshberger

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I'm not looking to part with my 18/20, so I went for the measurement option.

My standard case weighs in at 11.9g. (Case, fwd closure, aft closure.) Case with a JB-weld plugged fwd closure comes in at 12.4g.

I wasn't aware there was a solid plugged forward closure for this case.
There is a manufactured plugged closure, its available from Aerotech's online store and at least one dealer ( I just can't remember who).
 

dhbarr

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Thanks! So only two measurements away or so.

The RMS-RC 18/20 precedes the current RMS 18/20; the plugged forward is milled out of the same blank as the tube.
 

Tonimus

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If the RC 18/20 does not have a delay cavity, it should weigh the same without the aft closure as just the case of a regular 18/20 without closures. The aluminum that makes up the threads on the regular case should be enough to compensate for the end of the RC case.
 

dhbarr

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If the RC 18/20 does not have a delay cavity, it should weigh the same without the aft closure as just the case of a regular 18/20 without closures. The aluminum that makes up the threads on the regular case should be enough to compensate for the end of the RC case.
The few data sources I've found indicate a slightly thicker, perfectly-flat-inside-and-out north end. It also seems the case walls may in fact be somewhat thinner, which is what I'm trying to determine by weight , o.d., and i.d.

There are no forward threads; it is a unibody bulkhead.
 

rharshberger

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Too bad the AT website doesn't have the external dimension drawings for the RMS RC 18/20 like they do for the RMS 18/20.
 

dhbarr

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Too bad the AT website doesn't have the external dimension drawings for the RMS RC 18/20 like they do for the RMS 18/20.
Actually, since the assembly instructions for the old D2-RCT do have some scale drawings in them, it might be possible to get in the right neighborhood. Weight especially might be a SWAG though.

My hunch: the RMS-RC 18/20 is both lighter and shorter in OAL than the modern offerings, both desirable properties for some tiny projects I have in mind.
 

iqsy59

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I have both. I will compare them later this evening...

Cheers,
Michael
 

dhbarr

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I have both. I will compare them later this evening...

Cheers,
Michael
Cool beans! I'm guessing about 3mm shorter and a gram or two lighter than the modern version w/ the new plugged forward.
 

iqsy59

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I have both. I will compare them later this evening...

Cheers,
Michael
I wasn't able to find it this evening. I know it is hiding in one of my boxes of hardware! I will keep looking...

Cheers,
Michael
 

dhbarr

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I wasn't able to find it this evening. I know it is hiding in one of my boxes of hardware! I will keep looking...

Cheers,
Michael
Thanks for being a good sport!
 

dhbarr

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Just wondering if this elusive beastie happened to turn up? :D
 
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