Author Topic: 1/2 size replica of Lauson RSC  (Read 1621 times)

Offline Craig DeShong

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1/2 size replica of Lauson RSC
« on: October 02, 2017, 08:07:17 PM »

(yes- you have to connect the ignition circuit if you expect the engine to run)  :embarassed:

Ive been collecting Lauson air cooled small engines for years, so when I started thinking of what engine I might want to model, my thoughts moved to building a size model of a Lauson RSC591. 
The Lauson RSC, in its many derivatives, is probably the most prevalent model Lauson produced.  Lauson built these engines from around 1937 through shortly after WWII.  My collection includes a RSC591 so I had a candidate easily available from which to model.

I built the model from aluminum bar stock, there were no castings used in the creation of this model.  I have around 700 hours invested in this model. 
The model uses ball bearing main bearings (because the full size uses ball bearings and I was trying to closely reproduce the full size).  The model incorporates a one piece crankshaft, a cast iron cylinder liner and cast iron valve seats and guides, a functioning flyweight governor on the crankshaft (as the original), and a functioning float carburetor.  The ignition is battery-coil, though the points are under the flywheel as the original.

Ive included a few of the more interesting pictures I took during the build process.

1- Cutting fins into the block
2- Cam and valves
3- completed block
4- rings
5- crankshaft with flyweight governor
6- float carburetor
« Last Edit: October 02, 2017, 08:11:18 PM by Craig deshong »
Craig

Offline Admiral_dk

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Re: 1/2 size replica of Lauson RSC
« Reply #1 on: October 02, 2017, 08:51:57 PM »
Nicely executed model  :praise2: - never seen anyone like it before (except for the similarity to a Brigs & Stratton), but then I've never been to the US, so ....

The float is rather small - any problems get it to work as intended (weight vs. size) ?

Oh and welcome here  :)

Best wishes

Per

Offline fidlstyks

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Re: 1/2 size replica of Lauson RSC
« Reply #2 on: October 02, 2017, 09:00:58 PM »
This is Matt from Smokstaks. I think you will find this site interesting and more interest  with your creation. Glad you joined and posted.

Offline Craig DeShong

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Re: 1/2 size replica of Lauson RSC
« Reply #3 on: October 02, 2017, 09:54:56 PM »
Yes Per, getting the float to regulate the gas emitted into the carburetor bowl is a nightmare.  The float is so small that it has very little force to exert.  After MUCH trial and error, I finally settled upon the end of a sewing needle with a diameter of around .035 inches.  This is light enough for the float to lift.  It is lifted into a hole drilled in the carburetor lid with a #68 drill (.031 inch).  The float is the end of a wine bottle cork, treated with gas tank sealant.  Of course, you need to drink the wine before you can use the cork (jeez the sacrifices we make for this hobby  :lolb:).

I need to filter the gas (Coleman fuel) or the fuel delivery system is plagued with clogs.  I've gotten pretty adept at clearing them.

I've used this same mechanism with success on the RSC, TLC, and the VR I've posted recently.
Craig

Offline steamer

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Re: 1/2 size replica of Lauson RSC
« Reply #4 on: October 03, 2017, 12:40:27 AM »
Very nice indeed!   

Dave
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Offline Dave Otto

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Re: 1/2 size replica of Lauson RSC
« Reply #5 on: October 03, 2017, 01:10:17 AM »
Beautiful little engine Craig.

Dave

Offline littlelocos

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Re: 1/2 size replica of Lauson RSC
« Reply #6 on: October 03, 2017, 02:50:45 AM »
Very nicely done.  Love the sound.   :ThumbsUp:

Offline Admiral_dk

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Re: 1/2 size replica of Lauson RSC
« Reply #7 on: October 03, 2017, 07:53:01 PM »
Quote
The float is the end of a wine bottle cork, treated with gas tank sealant.  Of course, you need to drink the wine before you can use the cork (jeez the sacrifices we make for this hobby  :lolb:).

Hmm - if I had helped you empty it, it could have explained why I thought that it looked like a soldered float ....  :noidea:
..... on the other hand that would have removed my excuse for not knowing it's origin  ;)

All modern carburators I've seen, have the needle close to the hinge, giving it a ratio between 1:4 and 1:6 - this helps closing.

Online fumopuc

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Re: 1/2 size replica of Lauson RSC
« Reply #8 on: October 03, 2017, 08:18:51 PM »
Hi Craig, a beautiful model engine.
Kind Regards
Achim