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Author Topic: Line length  (Read 668 times)

Offline richardm

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Line length
« on: October 05, 2018, 03:40:10 AM »
Well I never

Just posted on a couple facebook pages pictures and a few specifications of running gear of my new ringmaster, actually, my second.

OS FP20 9X4 apc and 62' .012 lines

Never had so much attention, do I keep posting about line length to get friends? S?P

Serious am I that far off whack cause the plane seemed to fly OK on its first test flight, early engine cut due to split clunk line but wingover, loops in and out, horizontal eight, all good tension, could whip after the engine cut.........

Is there a formula?


Offline James Holford

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Re: Line length
« Reply #1 on: October 05, 2018, 04:49:56 AM »
It was me that responded to your post. Wasnt intentionally trying to be rude.  Was just concerned about the motor size and prop used at that line length.

 But if you are maintaining good line tension especially with .012's being better than .015's in this setup. Keep on keeping on :)

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Offline Jim Mynes

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Re: Line length
« Reply #2 on: October 05, 2018, 06:05:07 AM »
Iíd like to see some discussion on the topic as well. A couple of guys I fly with hook 68 foot Spectra lines on a .15 powered Jr. Flite Streak, I tell them shorter lines are better, and they ask all the why questions.
I donít know why, I donít have the answers, but the Stunt community Ďhive mindí agrees that 68í is for bigger planes.
I only use stainless, so I have no experience with Spectra. My Ringmaster gets 58í lines, .40 sized planes get 60í lines, and Iím just starting to dip my toe into larger planes on 64í lines. I believe thatís typical, and it seems to work well, but I donít know the physics behind it.
I have seen the light, and itís powered by a lipo.

Offline Ken Culbertson

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Re: Line length
« Reply #3 on: October 05, 2018, 07:32:01 AM »
It has been my experience that the lines need to be long enough to reach the handle. y1

Seriously, I think it is very much a function of your flying style and capabilities.  Longer lines let you fly faster and make the maneuvers larger.  You have longer flats in the squares, etc. but the trade off is more line drag producing yaw in corners, weight in the overheads and the plane is further away from you lessening your visual accuracy.  I have flown on 65' all of my life but I am planning to drop to 60' for next season.  It is the visual part for me.  I am farsighted and I could actually see more clearly at 65 than at 60 but as my age exceeded my line length that started to change and I now find the plane easier to see clearly at 60 so I am going to adapt.

I will leave it to the ones that really know what they are talking about to tell you more.

Good luck - Ken
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Online Tim Wescott

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Re: Line length
« Reply #4 on: October 05, 2018, 07:38:20 AM »
Well I never

Just posted on a couple facebook pages pictures and a few specifications of running gear of my new ringmaster, actually, my second.

OS FP20 9X4 apc and 62' .012 lines

Never had so much attention, do I keep posting about line length to get friends? S?P

Serious am I that far off whack cause the plane seemed to fly OK on its first test flight, early engine cut due to split clunk line but wingover, loops in and out, horizontal eight, all good tension, could whip after the engine cut.........

Is there a formula?

I've since converted it to a carrier plane, but I have a Ringmaster that came out of the delivery room at 32 ounces, with a 20FP and an APC 9x4.  It flew great on lines that were 60' eyelet to eyelet (so, pretty close to 62' by the rulebook -- I'm not sure how you're measuring your lines).  Having the long lines let me fly it faster and open up the maneuvers, both of which (I believe) helped me to avoid the Dread Ringmaster Stall -- the plane has done some hairy octagonal loops, but it's also done some pretty nice round loops, and square maneuvers with long enough flat sections between the big soft "corners" to score decently.

I've gotten as much as 475 points with that plane in Classic, when I wasn't nearly as good a pilot as I am now.
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Offline James Holford

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Re: Line length
« Reply #5 on: October 05, 2018, 07:48:42 AM »
I fly my Ringmaster with a .25LA and 9x5APC on 58'. Just what im comfortable with.

Heck I fly my now 40oz Twister with .46LA on 58' lol. I know it would perform just fine on 60'. Maybe even 62'. I just like it at 58' altho I may benefit from going to 60'. Might try one day.

As long as the line tension is there and it flies fine. Fly her til she fallas apart.


Now when I move on to bigger ships Ill of course use the appropriate line length that will help the plane fly to its best capability.

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Offline Gary Dowler

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Re: Line length
« Reply #6 on: October 05, 2018, 08:14:08 AM »
Well I never

Just posted on a couple facebook pages pictures and a few specifications of running gear of my new ringmaster, actually, my second.

OS FP20 9X4 apc and 62' .012 lines

Never had so much attention, do I keep posting about line length to get friends? S?P

Serious am I that far off whack cause the plane seemed to fly OK on its first test flight, early engine cut due to split clunk line but wingover, loops in and out, horizontal eight, all good tension, could whip after the engine cut.........

Is there a formula?
I've been flying planes similar to the Ringmaster for a couple years now. This year I reengined with a OS 20FP and a 9-4 APC and flying on 60' .015's.  Works beautifully , though .012's might be better b

Gary
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Online Brett Buck

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Re: Line length
« Reply #7 on: October 05, 2018, 09:00:54 AM »
Well I never

Just posted on a couple facebook pages pictures and a few specifications of running gear of my new ringmaster, actually, my second.

OS FP20 9X4 apc and 62' .012 lines

Never had so much attention, do I keep posting about line length to get friends? S?P

Serious am I that far off whack cause the plane seemed to fly OK on its first test flight, early engine cut due to split clunk line but wingover, loops in and out, horizontal eight, all good tension, could whip after the engine cut.........

    What is the question, exactly? 60-62' lines are pretty typical for a 20FP powered model, particularly a Ringmaster, which is *grossly* overpowered with a 20FP, running correctly. We got 3.8 second laps with the engine set properly and .015x60.
 
     .012 makes me a bit nervous, but should be OK if they are in perfect shape. Otherwise, you can adjust the line length +-1 foot at a time and see how it works. I would not expect to want to go shorter, just because the lap times will be so fast. It sounds like it is working pretty well as it is, is there any particular issue you are trying to solve?

    In this case, you are just trying to get it in the ballpark, refinement is not a word normally used in association with Ringmasters. Getting the elevator travel and control rates right is the most critical issue in any case, you can't use very much travel at all, and the stock control system rates (to the extent you can figure out what was intended) are vastly too fast. You can handle a bit higher control rates with the 20FP than with a Fox/McCoy, etc, but it's still almost comically slow, maybe +- 3/4" at the TE of the elevator with full handle motion.

     Brett

Offline Gary Dowler

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Re: Line length
« Reply #8 on: October 05, 2018, 10:47:01 AM »
Brett is right about the controls!  I had been trying to fly with controls that were WAY to fast! Couldn't figure why I was having such a hard time flying decently. Fought with it for 2 years thinking I was the problem. Then Mark Scarborough came with me one day and watched. He suggested a drastic slow down in my controls.  I reset things according to his suggestions and wow! What a difference!! A plane that had been hard just to keep level flight suddenly became nimble, but STABLE, plane!!  The problem I thought was all pilot error was 95% trim and control rate! Only had 18-20 degrees of elevator travel, (about the 3/4" Brett said) but this was  plenty for all basic maneuvers.

Gary
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Online Tim Wescott

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Re: Line length
« Reply #9 on: October 05, 2018, 10:55:52 AM »
... Only had 18-20 degrees of elevator travel, (about the 3/4" Brett said) but this was  plenty for all basic maneuvers.

That's good enough to do the pattern!  Of course, entering a serious stunt competition with a Ringmaster is kind of like showing up for a drag race with a lawn tractor, but still.
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Online Brett Buck

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Re: Line length
« Reply #10 on: October 05, 2018, 11:30:42 AM »
That's good enough to do the pattern!  Of course, entering a serious stunt competition with a Ringmaster is kind of like showing up for a drag race with a lawn tractor, but still.

  And, more to the point, adding more elevator beyond that starts hurting the turn rather than helping it. The way to set it is to start out very slow, and speed it up a little at a time, flight by flight, trying to turn as hard as you can, until is starts to stall in the corners. Then slow it back down a notch or two. That will get you all the travel the airplane can handle, without speeding it up to the point you can't fly it, or you stall it.

     People always talk about adding a "bit extra for emergencies" like it is some clever trick, but moving it further that it can tolerate is going to make the emergency worse - or create the emergency in the first place.

   Note again - this is not about "blocking" the travel of the system to limit it. Never, ever, "block" the control travel for this purpose. You *slow it down*, meaning a given amount of handle motion results in less elevator movement. Maybe a longer control horn at the elevator, a bigger ratio of the bellcrank span to the pushrod hole, or narrow the handle spacing. You are generally better off with adjusting it at the airplane end until it is close, rather than squeezing down the handle spacing, at least to start with. Use as much spacing as you can given the other limitations, and slow down the controls in the airplane. Then use the handle spacing for fine adjustment. Doing it this way reduces the effects of line compliance/"sag", which may not matter all that much on a Ringmaster, but will matter in most other cases.

    Brett

Offline Gary Dowler

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Re: Line length
« Reply #11 on: October 05, 2018, 12:03:22 PM »
My info base on the subject continues to expand.

Gary
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Online Dane Martin

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Re: Line length
« Reply #12 on: October 05, 2018, 12:08:23 PM »
I'd say, OS 20fp, APC 9x4 revved out, and back it down enough to keep it safe. 60' .015 lines.
I had 12's break, but if you're careful with them, it's not a big deal I guess. I think people would like the feeling of control difference between 12's and 15's though. Like a more solid feel.

I've asked the question about line lengths also. It kinda (kinda,in that this isn't by any means a rule to remember) boils down to, pick a known line length and trim your airplane to suit. So if you can fly all the manuevers you can fly on that set of lines, then they're correct. Until you get pretty good then experimentation yields results for things we don't know how to look for at our beginning stages.

Online Brett Buck

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Re: Line length
« Reply #13 on: October 05, 2018, 01:28:18 PM »
I'd say, OS 20fp, APC 9x4 revved out, and back it down enough to keep it safe. 60' .015 lines.
I had 12's break, but if you're careful with them, it's not a big deal I guess. I think people would like the feeling of control difference between 12's and 15's though. Like a more solid feel.

I've asked the question about line lengths also. It kinda (kinda,in that this isn't by any means a rule to remember) boils down to, pick a known line length and trim your airplane to suit. So if you can fly all the manuevers you can fly on that set of lines, then they're correct. Until you get pretty good then experimentation yields results for things we don't know how to look for at our beginning stages.

   I tell everyone to start with the 20FP/25LA with about .015x60-62', because that will be short enough to have line tension and moderate effect on the yaw angle (in case the leadouts are misplaced or not adjustable), and not too short to screw you into the ground when the engine is set correctly.

    The biggest issue, by far, is managing the speed *without* resorting to needling (or attempting to needle) the engine down excessively. FAR too many people equate "2-stroke" = "meltdown" (which it could be in some circumstances with vintage engines), and are afraid to run the engine like it needs to - medium 2-stroke in level flight.

    You can recognize them from on-line posts where they talk about 52' lines, "what happens when the wind blows!?" and "it just runs away!". "Running away" is the way it is *supposed to run*, and if you don't run it that way, you will not get the results that everybody else gets. Set the 20FP/APC 9-4 properly, on a Ringmaster, and I guarantee that wind will be the last problem you have. The wing is an inch thick and you are going 75 mph - wind is not an issue!

   To re-iterate, set the engine (20FP/9-4 APC) by peaking the needle on the ground, that is, as lean as it will go before it starts to sag, then back off richer until you get a *distinct* drop in speed, maybe 5-6 clicks. It should wind up in a medium 2-stroke in level flight, and speed up in the maneuvers. If it ever goes "over the top" lean in the maneuvers (like at the end of the flight), reset the needle 1 click richer on the next flight, until it doesn't. If it ever does more than an occasional misfire into 4, set it one click leaner on the next flight, so it never goes into a 4-stroke, or it goes "over the top" lean.

   Note that I am not giving RPM readings because I don't want you to go by RPM, go by the sound and how it works in-flight. A 20FP will usually be somewhere between 11,500-12,200 on the ground, at sea level, on 10% fuel, but that's not a goal to shoot for. Get it working, THEN tach it to see what it is doing. The "new" 25LA will be substantially faster than that to get the same level flight speed.

    Brett

p.s. again, .012 lines are OK if they are in good shape - but you are flying a 30-ish ounce airplane at up to 75-80 mph, it's not going to pull like a 1/2A. If someone already has those, keep going, but be very picky about the condition of the lines and discard them if they have *any* apparent issues.

Offline Ty Marcucci

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Re: Line length
« Reply #14 on: October 05, 2018, 01:41:22 PM »
It has been my experience that the lines need to be long enough to reach the handle. y1

Seriously, I think it is very much a function of your flying style and capabilities.  Longer lines let you fly faster and make the maneuvers larger.  You have longer flats in the squares, etc. but the trade off is more line drag producing yaw in corners, weight in the overheads and the plane is further away from you lessening your visual accuracy.  I have flown on 65' all of my life but I am planning to drop to 60' for next season.  It is the visual part for me.  I am farsighted and I could actually see more clearly at 65 than at 60 but as my age exceeded my line length that started to change and I now find the plane easier to see clearly at 60 so I am going to adapt.

I will leave it to the ones that really know what they are talking about to tell you more.

Good luck - Ken
« Last Edit: October 05, 2018, 05:25:17 PM by Ty Marcucci »
Ty Marcucci

Offline James Holford

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Re: Line length
« Reply #15 on: October 05, 2018, 02:06:26 PM »
Given Bretts response here... i feel like a idiot for even saying anything lol

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Offline richardm

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Re: Line length
« Reply #16 on: October 05, 2018, 02:21:11 PM »
It was me that responded to your post. Wasnt intentionally trying to be rude.  Was just concerned about the motor size and prop used at that line length.

 But if you are maintaining good line tension especially with .012's being better than .015's in this setup. Keep on keeping on :)

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Hi James all taken in good humor, we don't have a big control line community in New Zealand so discussions like these are great H^^

Offline James Holford

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Re: Line length
« Reply #17 on: October 05, 2018, 02:22:21 PM »
Hi James all taken in good humor, we don't have a big control line community in New Zealand so discussions like these are great H^^
Good deal bud :).

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Offline richardm

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Re: Line length
« Reply #18 on: October 05, 2018, 02:42:43 PM »
I have slowed my controls right down into the range mentioned an am pleasantly surprised with how well it turns

Online Brett Buck

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Re: Line length
« Reply #19 on: October 05, 2018, 05:52:31 PM »
Given Bretts response here... i feel like a idiot for even saying anything lol

   I am sorry, I had no intent to undermine what you said, in any way. Just great minds thinking alike, and one of them overthinking it.

    Brett

Online Brett Buck

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Re: Line length
« Reply #20 on: October 05, 2018, 06:10:03 PM »
I have slowed my controls right down into the range mentioned an am pleasantly surprised with how well it turns

   They can turn better than most people think - mostly because of the way they had been set up in the past, it just immediately stalled any time you touched the controls.  The two primary factors are getting the controls set up properly (very slow rates) and getting a good engine with a low-pitched prop, in that order. Saving weight helps, but not nearly as important as the other two, as long as it is within reason.

    In fact, do those two things, and then it turns so good, it tends to break the wings off! Particularly if you went for the "world's lightest Ringmaster".

     If the engine quits (Veco 19bb, 20FP, 15FP, etc) in a bad position, then it turns back into a Ringmaster, and you are going to have problems. Universal Stunt Hero David Fitzgerald is noted for crashing Ringmasters (other people's, like Ted's) while hot-dogging it for the crowd, and having the engine quit. I have seen it, it won't make a 180 degree turn from inverted at 45 degrees, to upright. David's experiments also conclusively proved it turns better with half the wing gone and the engine running, than both wings intact and the engine stopped. Proof is left to the reader.

     Brett

   

Offline James Holford

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Re: Line length
« Reply #21 on: October 05, 2018, 07:02:36 PM »
   I am sorry, I had no intent to undermine what you said, in any way. Just great minds thinking alike, and one of them overthinking it.

    Brett
Its all good buddy :)

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Offline Gerald Arana

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Re: Line length
« Reply #22 on: October 05, 2018, 07:18:06 PM »
   David's experiments also conclusively proved it turns better with half the wing gone and the engine running, than both wings intact and the engine stopped. Proof is left to the reader.

     Brett

 


Love it! LL~ LL~ LL~

Jerry


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