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Author Topic: Does the Ringmaster s-1 need offset rudder?  (Read 5043 times)

Offline aba183210

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Does the Ringmaster s-1 need offset rudder?
« on: January 04, 2016, 03:57:04 PM »
Good afternoon.

Yesterday a new Ringmaster (original size) was maidened. It flew Ok but I noted that there was some slack in the lines in high maneuvers and tended to fly with the outboard wing a bit high.

My instructor suggested offsetting the rudder but then I have seen ringmasters without it; in fact, the plans call for no offset.

Later I also found a slight warp in the outboard wing.

I already added 1 oz wingtip weight, but the leadouts aren't adjustable (I bought this arf from RSM).


Offline Tim Wescott

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Re: Does the Ringmaster s-1 need offset rudder?
« Reply #1 on: January 04, 2016, 04:21:31 PM »
Don't add offset to the rudder.

I don't know how much of a detriment the non-adjustable leadouts will be, but flapless planes don't seem to be as sensitive to that as flapped planes are.  If they come out in the stock location then it'll probably affect your line tension on the high lines and in overheads -- but not loops.

Get the warp out.  If you can see it flying with the outside wing high, then when you're feeding in up-elevator (for a loop or just high flight) it'll tend to fly in on you.

If you can go inverted, to so, and see how it is relative to level.  If the outside wing is always toward the canopy (i.e., if it's low in inverted flight and high upright), then the wing is warped and you need to work it out, whether you can see the warp or not.  If the outside wing is always away from the ground (i.e., high in both upright and inverted flight) then you need more tip weight.

If you already had whatever tip weight the plans called for and you added 1oz more, then it's way too much, and you must have a monumental warp.
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Offline Dane Martin

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Re: Does the Ringmaster s-1 need offset rudder?
« Reply #2 on: January 04, 2016, 05:10:45 PM »
Like Tim says, the warp is the biggest issue. Rudder offset won't do anything that you would need to worry about.
 The leadouts don't need to be adjustable. I got plenty that are fixed that do very well. The measurement should be about 2 1/8" back from the LE. If it's the ARF, that's probably correct and i wouldn't worry about that.

Other than that, make sure it's flying fast enough.

Offline Phil Spillman

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Re: Does the Ringmaster s-1 need offset rudder?
« Reply #3 on: January 04, 2016, 08:48:50 PM »
Hi You might want to sand or carve a slight airfoil into your rudder on the inside of the piece, toward the pilot, to mimic the idea first introduced in the green Box Nobler by GMA, I've done this on many of my profile planes and think it has helped in the flying of the units! Is it really necessary? Probably not! But I like the idea!

Phil Spillman
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Offline Bill Little

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Re: Does the Ringmaster s-1 need offset rudder?
« Reply #4 on: January 05, 2016, 09:48:38 PM »
I agree with Phil.  Almost all my stunt planes have an air foiled rudder.  Some it is on the plans, some not.  Just a flat airfoil, with the flat side facing the outside of the circle.  Don't know how much effect it has, but I like the way it looks! LL~

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Offline BillP

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Re: Does the Ringmaster s-1 need offset rudder?
« Reply #5 on: January 06, 2016, 11:03:06 AM »
My original (notched leading and trailing edge) Ringmaster flys straight and true on all maneuvers with 1/4" rudder offset and 1/16" engine offset...Fox 35, 60' x .015 lines.     
Bill P.

Offline Tim Wescott

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Re: Does the Ringmaster s-1 need offset rudder?
« Reply #6 on: January 06, 2016, 04:35:27 PM »
My original (notched leading and trailing edge) Ringmaster flys straight and true on all maneuvers with 1/4" rudder offset and 1/16" engine offset...Fox 35, 60' x .015 lines.     

OTOH, my S-1 flies straight and true with zero-zero offset.  I think my personal high point is 475 points, with (IIRC) 15 appearance points (it's pretty dented up).
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Offline BillP

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Re: Does the Ringmaster s-1 need offset rudder?
« Reply #7 on: January 07, 2016, 08:39:11 AM »
OTOH, my S-1 flies straight and true with zero-zero offset.  I think my personal high point is 475 points, with (IIRC) 15 appearance points (it's pretty dented up).

Since you quoted me...The OP asked about rudder offset so my response was to let him know adding it doesn't automatically make a plane fly like crap...and it can help with line tension. He may not be able to trim in desired line tension with "zero-zero". I've flown with the entire vertical stab broken off and seen no difference too but I don't build them that way but to each their own.

~~>If points have anything to do with it I get 476 + 16 for flying cl 5 yrs longer than your age  **)     
Bill P.

Offline Motorman

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Re: Does the Ringmaster s-1 need offset rudder?
« Reply #8 on: January 07, 2016, 10:19:10 AM »
I always put a little right rudder in just to make sure it's not going the wrong way. 1/16th - 1/8th is just fine.


MM

Offline Tim Wescott

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Re: Does the Ringmaster s-1 need offset rudder?
« Reply #9 on: January 07, 2016, 10:41:12 AM »
Since you quoted me...The OP asked about rudder offset so my response was to let him know adding it doesn't automatically make a plane fly like crap...and it can help with line tension. He may not be able to trim in desired line tension with "zero-zero". I've flown with the entire vertical stab broken off and seen no difference too but I don't build them that way but to each their own.

So the OP knows that he's got a lot of different ways to succeed!

~~>If points have anything to do with it I get 476 + 16 for flying cl 5 yrs longer than your age

Aaagh!  I'm doomed!
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Offline Terrence Durrill

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Re: Does the Ringmaster s-1 need offset rudder?
« Reply #10 on: January 07, 2016, 11:14:27 AM »

    As primarily a sport flier, I have always built the Sterling S-1 Ringmaster kits and I constructed all of them according to the plan recommendations.  I built my first one in 1955 and since that time have built another 5 or so.  I just like the way they look and I really don't think rudder offset affects the flight characteristics one way or the other.  The old S-1's just seem to last forever, baring a direct midair collision.    y1     D>K     H^^

Offline JoeJust

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Re: Does the Ringmaster s-1 need offset rudder?
« Reply #11 on: January 07, 2016, 11:30:40 AM »
All that effects the flight of a RM with a canopy or a rudder is that either really can screw up an otherwise perfect inverted landing.  Now how can a guy like me with far fewer than 8000 posts ever have a sensible answer to the original question? LL~
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Offline john e. holliday

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Re: Does the Ringmaster s-1 need offset rudder?
« Reply #12 on: January 07, 2016, 12:17:05 PM »
I have Ringmasters with rudder offset according to plan and some with out.   I do put a washer under the front engine lug also.
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Online Brett Buck

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Re: Does the Ringmaster s-1 need offset rudder?
« Reply #13 on: January 07, 2016, 12:26:25 PM »
 I just like the way they look and I really don't think rudder offset affects the flight characteristics one way or the other.  

   It's far less sensitive to offset than other designs because it's very short-coupled and the fin/rudder has an aspect ratio of about 1:2. There are usually so many more other things going on (like, the leadout being in the wrong place and space much too far apart) that this is a very minor effect.

    Brett

Offline aba183210

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Re: Does the Ringmaster s-1 need offset rudder?
« Reply #14 on: January 09, 2016, 06:08:18 PM »
I do thank you for your replies.

When was just learning to fly CL, the rudder of the Flite Streak Trainer came off but it did not make one bit of a difference in line tension or flight characteritics. The rudder had the 3/8 in offset as called for in the plans. I made a new rudder, with no offset at all, and the plane responded just the same.

As for the Ringmaster, I did straighten the warp as much as I could by using the heat gun, and put just a bit of offset engine thrust by using very thin washers; I left the rudder untouched. The result was that the line tension is much better now, even though I note that at times the outboard wing tends to "hunt," especially in windy conditions. This was the same behavior that my Magician exhibited, too.

One thing I note is that the Ringmaster I have takes twice as long to take off compared to the Magician, but does track like it's on rails.

It was not a monumental warp-it was just a tiny bit...but as I am aware, in CL, a tiny bit can make a lot of difference.

Today I was practicing some wingovers to get a feel of the plane. When my instructor test flew it last week with the recommended elevator throws (about 15 to 20 degrees), it was barely enough to save the plane from diving into the ground in an inside loop. He increased the throw of the elevator and now the plane responds well, like the Magician. I have yet to loop it with the new changes.

The plane completes a lap in 5 seconds, and the RPM is about 11,000. By performing some calculations, I found out that the speed of the plane is about 50 mph.

« Last Edit: January 09, 2016, 06:43:04 PM by aba183210 »

Offline Mike Keville

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Re: Does the Ringmaster s-1 need offset rudder?
« Reply #15 on: January 09, 2016, 08:33:51 PM »
Doesn't really need rudder offset.  What it DOES need is a longer control horn.  Learned that one from Bart Klapinski.  Makes a world of difference.
FORMER member, "Academy of Multi-rotors & ARFs".

Online Brett Buck

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Re: Does the Ringmaster s-1 need offset rudder?
« Reply #16 on: January 09, 2016, 08:57:48 PM »
Doesn't really need rudder offset.  What it DOES need is a longer control horn.  Learned that one from Bart Klapinski.  Makes a world of difference.


  Absolutely. Slowing the control rates down, so you have as little at +- 1/2" of elevator movement with full handle motion, is critical. Even more so than having a good engine.

     Brett

Offline Dane Martin

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Re: Does the Ringmaster s-1 need offset rudder?
« Reply #17 on: January 09, 2016, 09:22:19 PM »
I do thank you for your replies.

When was just learning to fly CL, the rudder of the Flite Streak Trainer came off but it did not make one bit of a difference in line tension or flight characteritics. The rudder had the 3/8 in offset as called for in the plans. I made a new rudder, with no offset at all, and the plane responded just the same.

As for the Ringmaster, I did straighten the warp as much as I could by using the heat gun, and put just a bit of offset engine thrust by using very thin washers; I left the rudder untouched. The result was that the line tension is much better now, even though I note that at times the outboard wing tends to "hunt," especially in windy conditions. This was the same behavior that my Magician exhibited, too.

One thing I note is that the Ringmaster I have takes twice as long to take off compared to the Magician, but does track like it's on rails.

It was not a monumental warp-it was just a tiny bit...but as I am aware, in CL, a tiny bit can make a lot of difference.

Today I was practicing some wingovers to get a feel of the plane. When my instructor test flew it last week with the recommended elevator throws (about 15 to 20 degrees), it was barely enough to save the plane from diving into the ground in an inside loop. He increased the throw of the elevator and now the plane responds well, like the Magician. I have yet to loop it with the new changes.

The plane completes a lap in 5 seconds, and the RPM is about 11,000. By performing some calculations, I found out that the speed of the plane is about 50 mph.




What Brett and Mike said in these previous posts are absolutely correct. Also, 5 sec laps sounds a little slow to me. I would speed that up a bit. I think like 4.2 to 4.6.
Also, with 20 degrees you should have nice corners. Are you nose heavy? I fly with my cg 1inch to 1.5 inch back. 1inch to start, then no more than 1.5 inch back. That with the handle spacing at 3inches.

Online Brett Buck

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Re: Does the Ringmaster s-1 need offset rudder?
« Reply #18 on: January 09, 2016, 09:24:59 PM »
Today I was practicing some wingovers to get a feel of the plane. When my instructor test flew it last week with the recommended elevator throws (about 15 to 20 degrees), it was barely enough to save the plane from diving into the ground in an inside loop. He increased the throw of the elevator and now the plane responds well, like the Magician. I have yet to loop it with the new changes.

    That sounds like it is nose-heavy, maybe severely.  That takes some doing, since I most of them balance at about the rear of the LE wood and fly fine.

    Brett

Offline Dan Berry

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Re: Does the Ringmaster s-1 need offset rudder?
« Reply #19 on: January 09, 2016, 10:18:52 PM »
I was thinking nose heavy as well.

Online Brett Buck

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Re: Does the Ringmaster s-1 need offset rudder?
« Reply #20 on: January 09, 2016, 10:43:24 PM »
I was thinking nose heavy as well.

   The fact that the round loops open up is a pretty classic symptom.

    brett

Offline aba183210

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Re: Does the Ringmaster s-1 need offset rudder?
« Reply #21 on: January 09, 2016, 11:05:00 PM »
When the plane was maidened a week ago, I did recall that the elevators had very little throw. I just consulted an online protractor to measure degrees and now I realize that my degree estimate was wrong-it was about 8 degrees or so. The instructor did adjust the throw and now it is indeed at 20 degrees at full handle now. The plane does respond well and does nice corners into the wingovers with relatively little input.

The CG is indeed where the last posters have stated. It is definitely not nose heavy.

As for the electric setup, it equals a .25 glow engine according to RSM. A 10 x 5 reverse pitch prop is used.. I will increase the RPM.




Offline Motorman

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Re: Does the Ringmaster s-1 need offset rudder?
« Reply #22 on: January 10, 2016, 12:06:45 AM »
Make sure your vertical CG is close to center (thrust line). If you have the (battery) weight hanging down it will cause all kinds of flight problems that you won't see until you try an outside loop. You might also want to cut 1/2" off the tips of your 10-5 to make a wide blade 9-5. 


MM

Offline Don Coe

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Re: Does the Ringmaster s-1 need offset rudder?
« Reply #23 on: January 10, 2016, 06:49:56 AM »
 H^^

Nice thread with lots of good information on the Ringmaster.


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