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Author Topic: S-1 Ringmaste  (Read 2063 times)

Offline Bootlegger

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S-1 Ringmaste
« on: February 27, 2019, 03:05:09 PM »

  I have an S-1 Ringmaster, not from a Sterling kit, but aftermarket kit mfg, and my question is where is the balance point/ c/g located?  The model is powered by an O S 25 L A  and on 58' .012 lines.

                  If this is posted in the wrong place please move to correct spot.  Thanks...
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Online Dan McEntee

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Re: S-1 Ringmaste
« Reply #1 on: February 28, 2019, 05:45:53 PM »
   Hi Frank;
    I would have to drag one off the wall to check, but anywhere from the bell crank pivot to the leading edge should get you airborne. Closer to the leading edge for first flights then experiment with tail weight after that. I don't think I have ever seen a tail heavy Ringmaster
   Type at you later,
  Dan McEntee
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Offline Leo Elder

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Re: S-1 Ringmaste
« Reply #2 on: February 28, 2019, 08:25:52 PM »
The plans that come with the RSM kit show the CG 1 3/4 inch behind the leading edge. You'll need tail weight to get it there for sure and it's lively balanced there. I fly mine with OS 20fp on 58' eyelet to eyelet .012 lines also.
You might want to do as Dan suggested and start closer to the leading edge.
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Offline john e. holliday

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Re: S-1 Ringmaste
« Reply #3 on: March 01, 2019, 09:51:31 AM »
As with any plane nose heavy gives you a chance to add weight.  Tail heavy not so good as I found out when I had a plane balanced according to the designer.  Was still learning back then.   But even now I'm still learning things. D>K
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Offline Jim Hoffman

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Re: S-1 Ringmaste
« Reply #4 on: March 10, 2019, 03:16:21 PM »
My Ringmaster CG is 3/4 inch aft of the LE.

Weight is 29.5 oz.
Lines .012 x 55' braided
OS 20 FP
APC 9-4  launch about 10.2 KRPM  lap time about 4.9 sec.
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Offline Gerald Arana

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Re: S-1 Ringmaste
« Reply #5 on: March 10, 2019, 06:32:41 PM »
Quote from: Jim Hoffman on March 10, 2019, 03:16:21 PM
My Ringmaster CG is 3/4 inch aft of the LE.

Weight is 29.5 oz.
Lines .012 x 55' braided
OS 20 FP
APC 9-4  launch about 10.2 KRPM  lap time about 4.9 sec.

Ditto! Mine might be an ounce lighter.........can't remember exactly.

Cheers, Jerry
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Offline wwwarbird

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Re: S-1 Ringmaste
« Reply #6 on: March 10, 2019, 08:17:15 PM »
Quote from: Bootlegger on February 27, 2019, 03:05:09 PM
  The model is powered by an O S 25 L A  and on 58' .012 lines.

 IMO people often get too hung up on "per the plan" CG points. Assuming it's not built heavy as a brick you'll be good to go as is. Take it out and fly it and maybe add a little bit if weight if you decide to, but I doubt you'll feel the need.
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Offline wwwarbird

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Re: S-1 Ringmaste
« Reply #7 on: March 10, 2019, 08:18:41 PM »
Quote from: Dan McEntee on February 28, 2019, 05:45:53 PM
   I don't think I have ever seen a tail heavy Ringmaster

 Only the ones that are balanced per the plan.  ;D
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Offline Jim Hoffman

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Re: S-1 Ringmaste
« Reply #8 on: March 10, 2019, 09:38:34 PM »
Quote from: wwwarbird on March 10, 2019, 08:17:15 PM
IMO people often get too hung up on "per the plan" CG points. Assuming it's not built heavy as a brick you'll be good to go as is. Take it out and fly it and maybe add a little bit if weight if you decide to, but I doubt you'll feel the need.

Don't fly a model with whatever CG it came off the building board.  You risk having an aft CG that might make the airplane difficult to fly. 

Do your best to put the CG in the correct spot, and biased towards nose heavy.  Sometimes that is not what is on the plan.
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Offline FLOYD CARTER

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Re: S-1 Ringmaste
« Reply #9 on: March 28, 2019, 12:07:24 PM »
It has always puzzled my why my scratch-built 22 oz. Ringmaster S-1 balances at the back edge of the leading edge block (built up, of course).  That's about 1" from the LE. Seems like nose=heavy, but it flies fine, and still turns like it should.

Sometimes, theory just doesn't apply.
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Offline pat king

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Re: S-1 Ringmaste
« Reply #10 on: March 28, 2019, 01:02:26 PM »
20% of Mean Aerodynamic Chord is 1.86" aft of the leading edge on an S1 Ringmaster. Starting forward of that is not a bad idea. I would not recommend going to 25% of MAC which is 233" aft of the leading edge. The safest way is to start at about 12% of MAC (.93) aft of the leading edge and move it back until you like the way it flys. If you get to the point the airplane is starting to get unstable you have the CG too far aft. The Ringmaster has a giant elevator, you can make it turn with the CG way forward. Racing airplanes typically have the CG at around 10% of MAC to make them stable.

Pat
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