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One I’ve never seen before.

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One I’ve never seen before.

Post  batjac on Sat Nov 04, 2017 11:02 pm

I was looking at an old Sterling PT-19 plan on Outerzone, and it had a drawing for something called an “Auto Magic Bellcrank”.  It took me a couple of minutes to find what the plans were talking about.  But now that I see, this is exciting.  Well, mildly exciting.  I doubt I’ll ever make one, but it’s a great concept.  Kind of an “Around the Pole” on auto-pilot.  Maybe one of Y'all have done this before?






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Re: One I’ve never seen before.

Post  MauricioB on Sat Nov 04, 2017 11:26 pm

batjac wrote:I was looking at an old Sterling PT-19 plan on Outerzone, and it had a drawing for something called an “Auto Magic Bellcrank”.  It took me a couple of minutes to find what the plans were talking about.  But now that I see, this is exciting.  Well, mildly exciting.  I doubt I’ll ever make one, but it’s a great concept.  Kind of an “Around the Pole” on auto-pilot.  Maybe one of Y'all have done this before?






The Mildly Excitable Mark

Hello, do you have the link where is this? ... I have to translate it and understand it, I find it interesting .....
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Re: One I’ve never seen before.

Post  NEW222 on Sun Nov 05, 2017 2:31 am

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Re: One I’ve never seen before.

Post  fredvon4 on Sun Nov 05, 2017 9:46 am

Hummm.... me thinks this may work for my speed plane testing

I guess one big maybe is need to ensure good line tension on longer lines and only fly it on a dead calm day
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Re: One I’ve never seen before.

Post  roddie on Sun Nov 05, 2017 11:28 am

That is a very interesting concept! The pole-height would obviously be a key-element. I wonder if "hunting/porpoising" could be a problem? It states that both lines be exactly the same length.. which is understandable. Why not use a "single-loop" of line.. and provide a central post on the pole-units' "fixed" line-connection part.. similar to a neutral-adjuster on some of the Cox handles? This would provide for "some" trimming of the flight-characteristics.. before choosing to alter the models' balance-point.  Huh...  Huh...  Huh...

I'm terrible with photo-editing.. but here's an image of my idea.. Laughing

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Re: One I’ve never seen before.

Post  MauricioB on Sun Nov 05, 2017 3:25 pm

NEW222 wrote:Hey there Mauricio. Lets try this:

https://outerzone.co.uk/plan_files_02/2024/PT-19_oz2024.pdf

Thanks for the link! and your attention, I just have that plane in my files, but I had not observed in detail and therefore I see this flight proposal ... it will be interesting to study it!
Thanks again, how is your name?
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Re: One I’ve never seen before.

Post  NEW222 on Sun Nov 05, 2017 7:50 pm

MauricioB wrote:
NEW222 wrote:Hey there Mauricio. Lets try this:

https://outerzone.co.uk/plan_files_02/2024/PT-19_oz2024.pdf

Thanks for the link! and your attention, I just have that plane in my files, but I had not observed in detail and therefore I see this flight proposal ... it will be interesting to study it!
Thanks again, how is your name?

It is actually a name I have had for a long time online. It was a name I used when actively into shooting sports years ago. I started out and enjoyed shooting .22 caliber rimfires, and as I was new to it all, I decided NEW222 (new to twenty-two). Hope this helps, or were you wondering my actual name?
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Re: One I’ve never seen before.

Post  MauricioB on Sun Nov 05, 2017 8:54 pm

NEW222 wrote:
MauricioB wrote:
NEW222 wrote:Hey there Mauricio. Lets try this:

https://outerzone.co.uk/plan_files_02/2024/PT-19_oz2024.pdf

Thanks for the link! and your attention, I just have that plane in my files, but I had not observed in detail and therefore I see this flight proposal ... it will be interesting to study it!
Thanks again, how is your name?

It is actually a name I have had for a long time online. It was a name I used when actively into shooting sports years ago. I started out and enjoyed shooting .22 caliber rimfires, and as I was new to it all, I decided NEW222 (new to twenty-two). Hope this helps, or were you wondering my actual name?
The story of NEW222 is interesting! ... but when someone responds to me, when someone takes their time to give me some information, I'm really interested in their real name, you have no obligation, it's simply valuing your person on my part and not be an anonymous to me. Thumbs Up
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Re: One I’ve never seen before.

Post  batjac on Sun Nov 05, 2017 10:12 pm

roddie wrote:That is a very interesting concept! The pole-height would obviously be a key-element. I wonder if "hunting/porpoising" could be a problem? It states that both lines be exactly the same length.. which is understandable. Why not use a "single-loop" of line.. and provide a central post on the pole-units' "fixed" line-connection part.. similar to a neutral-adjuster on some of the Cox handles? This would provide for "some" trimming of the flight-characteristics.. before choosing to alter the models' balance-point.  Huh...  Huh...  Huh...

I'm terrible with photo-editing.. but here's an image of my idea.. Laughing


When I was looking at it, I thought it'd be easier to do a capture washer like on a SIG handle, if I were going to do one.

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Re: One I’ve never seen before.

Post  roddie on Mon Nov 06, 2017 3:23 am

batjac wrote:
roddie wrote:That is a very interesting concept! The pole-height would obviously be a key-element. I wonder if "hunting/porpoising" could be a problem? It states that both lines be exactly the same length.. which is understandable. Why not use a "single-loop" of line.. and provide a central post on the pole-units' "fixed" line-connection part.. similar to a neutral-adjuster on some of the Cox handles? This would provide for "some" trimming of the flight-characteristics.. before choosing to alter the models' balance-point.  Huh...  Huh...  Huh...

I'm terrible with photo-editing.. but here's an image of my idea.. Laughing


When I was looking at it, I thought it'd be easier to do a capture washer like on a SIG handle, if I were going to do one.

The Lazy Mark

Yes.. whichever method works. If I'm interpreting the instructions correctly; raising the model (static) above the four-foot top-of-pole height, induces "down-elevator" and below it; induces "up-elevator". An adjustable line-loop would theoretically help to trim the altitude "range" at which the model flies.. because it won't likely hold a perfectly-level line. If there turned out to be a two-foot variance in altitude; we'd want to trim the model to fly between 3 and 5 feet.

Maybe the design takes care of that.. as long as the elevator is level at 4 feet..?? Huh...

I also have to wonder whether line-spacing options at the pole, might help to trim variances in altitude? A 1:1 ratio may not work as well for this application. A "wider" spacing might reduce variances in altitude.. because of increased control-deflection.

Then there's the matter of launching the model. Could it R.O.G. (full-up elevator) and recover to level-flight before going into a wing-over? Maybe it would need to be launched from 4 feet above the ground (pole-height)..

I love this stuff Cool and although it's not U-control, it "is" something that I would have the space to do here at home.
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Re: One I’ve never seen before.

Post  944_Jim on Mon Nov 06, 2017 2:10 pm

This is really not very different from the first few times we all flew C/L. Just like I tried to get my boys to understand.
"Don't move your arm up or down, Junior. The plane will come up to your arm. Don't try to land, Junior. The plane will start down as it slows down. The elevator will start "up" as the plane drops below your arm, and basically land itself."

Yes, the plane needs to be basically trimmed to avoid porposing. And if the lines are different lengths, then yes, the plane will NOT be straight out from the "handle." I wouldn't try to set the lines for a high flight, because there is no real pilot to bring the plane close to the ground from slow speed at engine-off time. I see a potential crash from a high altitude, slow-speed stall coming from that!
Obvoiusly, the post will need to be firmly planted, because as the plane circles, it will try to dislodge the pole. I bet a 5 gallon pail with a post set in concrete would be plenty considering our line pulls.
However, it is a neat way to fly a plane on short lines in limited space.
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Re: One I’ve never seen before.

Post  roddie on Mon Nov 06, 2017 6:20 pm

944_Jim wrote:This is really not very different from the first few times we all flew C/L. Just like I tried to get my boys to understand.
"Don't move your arm up or down, Junior. The plane will come up to your arm. Don't try to land, Junior. The plane will start down as it slows down. The elevator will start "up" as the plane drops below your arm, and basically land itself."

Yes, the plane needs to be basically trimmed to avoid porposing. And if the lines are different lengths, then yes, the plane will NOT be straight out from the "handle." I wouldn't try to set the lines for a high flight, because there is no real pilot to bring the plane close to the ground from slow speed at engine-off time. I see a potential crash from a high altitude, slow-speed stall coming from that!
Obvoiusly, the post will need to be firmly planted, because as the plane circles, it will try to dislodge the pole. I bet a 5 gallon pail with a post set in concrete would be plenty considering our line pulls.
However, it is a neat way to fly a plane on short lines in limited space.

Hi Jim, I was hoping for more input on this concept! The "pole"...... Huh... I was thinking the very same thing for maximum rigidity. It could double as a bird-feeder in the Winter..! Laughing

"RTP"-flying has been discussed here.. but not "free-flight" RTP. There's a VERY cool YouTube vid on free-flight RTP using small rubber-powered models that wouldn't place much stress on a center-pole.

I thought about "bracing" a pole with four "guy-wires" and eye-screws spaced 90 degrees apart, having rope-tensioners to keep it taught. I'm certainly not opposed to digging a hole in the center of my yard.. and sinking a 5-gal. bucket to accept a sleeve set in concrete!! The old free-standing cloths-line poles were done similar to that.

I'll likely try to build one of these.. because I really like the concept! I've been thinking on what to use for a "pole"... and a way to improve on the pole-top bearing unit. EMT steel-conduit comes to mind for the pole.. with a hardwood dowel insert-plug at the top. An "axle" for the pole-top unit "could be" a nail.. as illustrated.. but a better solution would be to drill the hardwood-plug to accept a threaded-insert for a machine-screw.

Then there's the "line-holder" fabrication. In my opinion;... it makes sense to spread the line-pull forces 50/50 above/below the pivot-bearing.. as in the original and "simple" concept-illustration. Keeping it simple should be kept in mind.. along with making sure that the unit rotates freely and maintains a constant perpendicular position to the ground. A "fender-washer" over the pivot-plate might help with this.?? (I'm thinking it out in my head as I type.. Laughing )








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Re: One I’ve never seen before.

Post  Oldenginerod on Mon Nov 06, 2017 6:35 pm

Do you have these over there?

We call 'em Star Pickets.  All different lengths.  6' is common, so drive it in 2' and you've got your 4' pole.  It'll be plenty rigid enough.  Would be easy to rig up a bolt-on cap with a pin/bearing attached to the top.  Not too hard to remove when you're done.
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Re: One I’ve never seen before.

Post  944_Jim on Mon Nov 06, 2017 7:27 pm

I think a piece of fence pipe in a bucket of concrete would be plenty. If the pipe/post were sunk in dirt, then the radial pull would eventually well/hog-out the hole. While our little planes don't pull like my kid on the basketball goal, it still is a constant that over time would need to be watched.
Considering the parabolic caps that go on top of fence posts, there is the very top where you could bolt a bearing through its inner-race. Then a plate of plywood could be mounted on the bearing's outer race. And then, just follow the diagram! I bet an old roller-blade wheel could even be pressed into service as the "turntable" that the 2-line "handle" attaches to. They have very low resistance bearings. I know $6 buys a 50 lb sack of concrete, and I know it takes more effort to rock a mailbox in a concrete sleeve out of the ground (thanks neighbor for testing it with your new truck!). If I had enough room for a 50 foot diameter circle, I'd try this with the boys' slabby profile trainer.
I do suspect that the lines would need to be shorter than normal, since we would have to expect some internal friction on the spindle. You would hate to see your creation spin around and wind up the lines of it couldn't break that friction point. We overcome that by using our feet to follow the plane...the plane doesn't really pull us!
My only other concern is wind...what happens if the plane blows in on the upwind side? Again, shorter lines sounds like the best aid by minimizing the time spent upwind. However, thnking of a model on 15 foot lines just makes me feel dizzy...
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Re: One I’ve never seen before.

Post  roddie on Tue Nov 07, 2017 9:25 am

There's two factors that I'd be dealing with. A maximum 35' diameter safe-clearance for a flying area.. and hard-pack gravel soil which would need to be excavated using a pick-axe. A pipe-sleeve set in concrete is my best option for installing a rigid pole. The pole would be secured in the sleeve using a cotter-pin. The pole could be removed and the sleeve capped when not in use.

The "Auto-Magic" instructions state 12-15 foot lines for use with the 4 foot pole-height. Longer lines may not yield enough elevator-deflection without increasing the height of the pole. That line-length would be ideal for the space that I have.

Not to stray too far off-topic.. but a while back; CEF member Ian1954 built a system with a very short "mono-line" for flying a small EP airplane with elevator/throttle control via RC. Pitch was very hard to judge/control, due to high-speed and issues with pole-flex. We brainstormed back and forth via email discussing a pole-top bearing-design to allow "stunting".. and came up with a "bail" (like on a fisherman's spinning-reel) attached to the bearing, which would "swivel" over the pole-top from one side to the other. During this time, Ian found an old illustration for a two-line RTP system having a "single-line" mechanical-control of the models' elevator from outside the circle.

Here's that illustration..



It's a bit involved.. but if the image is enlarged, it's easier to see how it works. A fisherman's "swivel" keeps the single (actuator) line from twisting-up.. and a tension-spring holds full-deflection one-way on the handle-unit. A pulley-system is used on the single actuator-line for smoothness of operation. Note the "control-stick" for the actuator-line outside the circle.
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Re: One I’ve never seen before.

Post  fredvon4 on Tue Nov 07, 2017 1:45 pm

I intend to play "tether car" in the air after seeing this device.... had seen similar before and poo-pooed the concept

BUT I do want to play in the CEF speed challenge ---BUT I simply can NOT fly a plane that fast in a circle safely any more

AND I just have enough space to fly a pure level path and not worry about my power lines with this tether method

As noted a gust of wind WILL cause a loss of plane....more so out on 32' lines vs faster speed/ higher centrifugal force on 15' lines suggested in the original post
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Re: One I’ve never seen before.

Post  944_Jim on Tue Nov 07, 2017 4:01 pm

Wow...that's a cool use for this!

We should be able to use an online calculator for line pulls. What, .75 lb model? Most are 5 oz give or take. Maybe .33 lb?

Ok...if I have this right: 15' radius, 45 mph, 5 oz model pulls right at 2.8 lbs.

And that works out to just a little over 42 rpm...just under 1.5 second laps!


Last edited by 944_Jim on Tue Nov 07, 2017 5:12 pm; edited 2 times in total (Reason for editing : Ran the math online)
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Re: One I’ve never seen before.

Post  roddie on Tue Nov 07, 2017 5:28 pm

fredvon4 wrote:I intend to play "tether car" in the air after seeing this device.... had seen similar before and poo-pooed the concept

BUT I do want to play in the CEF speed challenge ---BUT I simply can NOT fly a plane that fast in a circle safely any more

AND I just have enough space to fly a pure level path and not worry about my power lines with this tether method

As noted a gust of wind WILL cause a loss of plane....more so out on 32' lines vs faster speed/ higher centrifugal force on 15' lines suggested in the original post

Hi Phred, Don't forget.. the OP instructions call for a 4 foot pole. When/if you increase the distance from the pole, the elevator throws are reduced. Maybe you could compensate by presetting "extreme" throws on the models' linkage? The instructions also call for 3/8" of rudder-offset.. and that's for 12-15 foot lines. Lines twice that long may not work.. or may require a much higher pole. I suppose the only way to know is to try it..

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Re: One I’ve never seen before.

Post  Ken Cook on Wed Nov 08, 2017 4:17 am

We have a device from the 50's that allows flying outside of the circle. I have to say it's not for those with little experience. There's just too many factors that usually result in a crash. Here's my flying partner Dan using it with the club trainer, you can hear him mention it's barely controllable. https://www.facebook.com/PhillyFliersCL/videos/vb.513140418756097/992979427438858/?type=2&theater
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Re: One I’ve never seen before.

Post  Mark Boesen on Wed Nov 08, 2017 2:42 pm



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Re: One I’ve never seen before.

Post  MauricioB on Wed Nov 08, 2017 3:20 pm

Mark Boesen wrote:


Hello, that looks very retro! great, has a single line ?, how is it working ?, or the model is already pre-established before starting the flight ??.
Is there a video? That's a novelty for me ..... I could fly my U / C and enjoy them without getting feel sick! Very Happy
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Re: One I’ve never seen before.

Post  Mark Boesen on Wed Nov 08, 2017 9:13 pm

It's from Wen-Mac, c. 1959. Uses two lines to plane, one fixed and other moves with joystick, one line to pylon, wish i had instructions...
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Re: One I’ve never seen before.

Post  crankbndr on Wed Nov 08, 2017 9:27 pm

There are two on eBay now, the instructions are on back of box but can’t get good view of them.

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Re: One I’ve never seen before.

Post  Mark Boesen on Wed Nov 08, 2017 10:09 pm

cool, thanks! looks like up line is attached to joystick and down is looped around top of poll.
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Re: One I’ve never seen before.

Post  Ken Cook on Thu Nov 09, 2017 3:12 pm

Here is a picture of the unit my buddy Dan flies with. He's since redesigned the line attachments. We haven't had a chance to try again. It should be soon. We have flown .35 size planes on it though. https://www.facebook.com/PhillyFliersCL/photos/a.513142608755878.1073741825.513140418756097/993049194098548/?type=3&theater
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Re: One I’ve never seen before.

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