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General control line discussion => Open Forum => Topic started by: goozgog on October 06, 2013, 02:33:35 PM
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I promised to report on my progress with the
Ringmaster Biplane after it flew, and since it's
Ringmaster weekend, I'm going to indulge myself,
so here it is.
What this plane is, is two Sterling Jr. Ringmaster
wings attached to a S-1 Ringmaster fuselage and tail.
The bell crank position, L/G position and C.G. are
identical to the S-1. I'm sure I'm not the first person
ever to do this.
I've been pleasantly surprised that , so far, no one
has disputed it's provenance as a true Ringmaster.
Since Matt Kania designed all of the airframe except,
the struts, and wing mounts, I feel it's an honest and
true Ringmaster blend. Not for O/T though!
The good news and the bad news is that it flies
like a Ringmaster. No better and no worse. Several
people have flown it and everyone agrees that it's
a decent flier. Len Bourel completed the full pattern
with it on it's fifth flight (and his first) and that just
about says it all.
Everyone was happy with the LA.25 power but I
think it might be better with an LA.40. I think I can
feel the drag of the second wing. At 30.4 Oz and
400 sq/inch , it isn't heavy, but flying in yesterday's
strong winds, I feel I want more power overhead.
The engine is a LA.25 with a metal back plate and
venturi NVA. The stock OS muffler was included in
the balance calculations and works well.
I changed the prop up from a Master Airscrew 9-4
to a 10-6 and that works better.
The plastic clunk tank is mounted inboard and is on
muffler pressure.
The entire power system is pleasant and reliable.
The lines were 60' - 0.15
Several people seem interested in building a bipe,
so here's a few things that might help.
I used Adobe Illustrator's " Blend/steps/ expand"
function to generate the Jr. Ringmaster ribs. Then I
stuck the printout to the 1/16" balsa and hand cut them.
This is fast and accurate. If anyone wants to build a
Bipe or a Jr. Ringmaster, I can send them a PDF file
to print.
I always build up my profile fuselages but it isn't
necessary for this plane. The important thing is to
get the wing mounts aligned " Zero/Zero" to the
thrust line. This is easy but important.
The separation of the wings is dictated by sitting
the top wing on top of the S-1 wooden "canopy"
and the bottom wing on the bottom of the S-1
fuselage. If anyone is interested, I'll happily send
them a simple drawing of the struts and mounts.
The lead out guides are mounted to the struts and
needed to be adjust much farther forward than
I expected. The picture shows them in the
"too far aft" position.
So that's about it. This is a nice sport plane and
something different for Ringmaster events.
I think Matt Kania would be pleased.
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I like it Keith!!! Wish I had one but I have too many other projects in the assembly line right now. >:(
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8) 8) 8) 8) 8)
Marcus
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Hi Keith!
It looks very good and like it could have been a kit in the Ringmaster line up. It sounds like you might need a bit more power as you say.
Everything about the model is Ringmaster so I do believe it should be a recognized "Variant" with the BOTR!
BIG Bear
RNMM/AMM
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Thanks John and Bill.
This design is so obvious that I'm
slightly amazed Sterling didn't kit it.
They had all the tooling.
Perhaps they tried it but it just didn't
fly well made out of oak. ~>
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Awesome, Glad she is a winner. That is encouraging. Mine is progressing along. 480 sq" and a ST .34 for power. I am hoping that is enough.
Ken
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Hi Keith;
Next time out, try a APC 10-4 and spin that puppy up to at least 10,000 RPM and see what happens. A 10-6 is over proping that engine and it's not getting too it's power band. Might even go to 10,500. Love the airplane, nice blend of te parts. Kind of reminds me of the Over-Easy bipe.
Good luck and have fun with it,
Dan McEntee
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Will do Dan.
I built the entire plane with materials
I already had in my shop.
The Bipe will probably improve with
some adjustments.
Cheers!
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Sounds great that the bipe is working. Like Dan says a 10-6 is too much prop.
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Looking good Keith,Maybee one of the kit guys will like it enough to make a few up.It looks like it will be a barrel of fun.Jeff
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I promised to report on my progress with the
Ringmaster Biplane after it flew...
I think Matt Kania would be pleased.
Does look really nice. With only slightly more wing area than an S-1 it should fly about the same.
Placing the top wing about 2 in. higher might help. Most full size bipes use at least 1 chord length between the wings to reduce drag, esp. in maneuvers.
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Good point Phil.
The mean chord is 6.75" so it would only need .75" more
separation to meet the "rule of thumb" of one chord width.
(11% deviation)
The separation between the wings was dictated
by the height of a S-1 Fuselage. Since the concept
was to build a Ringmaster biplane and not an ultimate
biplane, I decided to go with the Ringmaster dimension.
This is actually a non issue since the plane flies fine.
CONGRATULATIONS to everyone on the 2332 Flights!
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Very Nice, Keith very job !
Cremon - Brazil
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Pat King does a Ringmaster Biplane (and triplane, for that matter).
They're more an "optimized biplane" rather than what you did here, in that Pat made them distinctly Ringmasters, but didn't particularly follow any existing designs.
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Could you please send me the pdf file with the ribs. Mike Stinson.
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Really nice job! H^^
Ya gotta lobe a biplane that stunts!
Good for you!
CB
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It's fun to see this post resurrected from the bin.
The Ringmaster Bipe is alive and doing well with
minimal changes. I took it down to Brodak's in 2014
and several good people gave it their approval.
Greetings to Phil Spillman!
I still prefer an S-1 in winds over 20 mph.
Sorry Michael, but the computer that held the
rib PDF is long gone. The ribs are just Jr. Ringmaster
ribs with two at the outboard tips to sandwich the
struts as the picture shows.
Cheers! - K
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A quick dig through the archives turned up these.