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Author Topic: Adjusting Incidence on a Tumblng Pigeon DT CLG  (Read 1907 times)
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Sailaway
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« on: August 27, 2018, 05:15:09 PM »

Sorry for the very novice question. But how does one adjust incidence in the CLG with Tumbling Pigeon DT? I see clearly in the DT where the  latter boom pops up. Same as in TLG. I cannot grasp the concept after seeing so many plans here as how the tail incidence is finely adjusted. Appears the 2-56 screw tapped at the TE of the wing will only move the TE of the wing up as the boom is fixed ?? What am I missing here? Thanks in advance and as always for helping me understand this as I am for the right reasons moving to the Tumbling Pigeon DT, mainly to build light.

Cheers.
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danberry
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« Reply #1 on: August 27, 2018, 08:12:42 PM »

Up or down. That's what it does.
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Sailaway
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« Reply #2 on: August 27, 2018, 09:34:03 PM »

but how sir? the 2-56 nylon screw is at the wing Trailing Edge and what appears to me is that the front end of the carbon boom is fixed. So the TE of the wing moves up or down and not the elevator? I am missing something or not reading the plans right? Help me understand a bit further please
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flydean1
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« Reply #3 on: August 27, 2018, 10:02:37 PM »

Lets see now...If you can move the wing TE up and down, why ever would you want to move the elevator.  Most TLG/CLG gliders don't have one separate from the stabilizer.  You're changing the relative angle of the wing relative to the stab.  It works really well, and lasts a long time.
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danberry
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« Reply #4 on: August 27, 2018, 11:09:20 PM »

Yes the wing moves up or down as necessary.   Tiny adjustments have big consequences on a CLG. 1/8 turn on a 2-56 is a big adjustment here. If you run out room needing to lower the TE ….. make some room.
These things fly at less than 1/2 degree decalage. Give or take a foot.
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danberry
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« Reply #5 on: August 27, 2018, 11:10:34 PM »

If we knew where you were, we could likely point you to help.
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Tapio Linkosalo
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« Reply #6 on: August 27, 2018, 11:53:49 PM »

These things fly at less than 1/2 degree decalage. Give or take a foot.

Decalage is the word. Difference in angle between wing and tail. When you adjust the model (e.g. by changing the tailplane), what you essentially do is adjust the decalage. Hence it does not really matter if you adjust the wing or tail angle, the outcome is the same. Move wing trailing edge down does the same as moving the tailplane trailing edge up. And vice versa.
 
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Sailaway
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« Reply #7 on: August 28, 2018, 12:07:03 PM »

Thank you all. This is a new concept for me. But thanks for confirming that the Carbon rod boom is stationary and the entire TE of the wing moves up, however small ( 0.5 degrees or there about) that gives the same effect as up elevator. Just one thinks we have the needed knowledge, then it is great to change the paradigm. Will try out building now.
Cheers and thanks again.
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ram
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« Reply #8 on: August 28, 2018, 02:49:06 PM »

the entire TE of the wing moves up, however small ( 0.5 degrees or there about) that gives the same effect as up elevator.

It's the opposite effect.
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flydean1
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« Reply #9 on: August 28, 2018, 02:57:26 PM »

Note reply from Ram. 

Also from DanBerry.  If we knew your location, we might get you to someone who can save you a lot of frustration.
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mike
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« Reply #10 on: August 28, 2018, 03:04:56 PM »

I'm confused here.  Please explain 'tumbling pigeon DT'.  I've never heard the term.  I'm familiar with the tip up wing DT often seen on TLGs - mine's in the picture below.  If it had an adjustment screw, it would be screwed through where my fingers are with protruding end resting on the main fuselage.  If screwed further through its threaded hole in the 'wing' part of the fuselage, it would serve to jack the hinge apart, increasing the wing incidence relative to the tail.
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Re: Adjusting Incidence on a Tumblng Pigeon DT CLG
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ram
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« Reply #11 on: August 28, 2018, 03:26:25 PM »

I'm confused here.  Please explain 'tumbling pigeon DT'.  I've never heard the term.  I'm familiar with the tip up wing DT often seen on TLGs - mine's in the picture below.  If it had an adjustment screw, it would be screwed through where my fingers are with protruding end resting on the main fuselage.  If screwed further through its threaded hole in the 'wing' part of the fuselage, it would serve to jack the hinge apart, increasing the wing incidence relative to the tail.


Wing pivots at the front vs the back causing the "tumbling pigeon" action.  There are plans here:

https://www.amaglider.com/?p=view&a=stans-stuff_2016-2017

Rey
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NormF
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« Reply #12 on: August 28, 2018, 03:40:15 PM »

The “tumbling pigeon” effect is a result of the rear of the wing raising instead of the front (as in your photo). The glider tumbles down and does not stabilize or parachute down as in a tip up tail system. An example can be seen in Stan’s catalog. https://amaglider.com/?p=view&a=stans-stuff_2016-2017

Norm

Rey types faster!


I'm confused here.  Please explain 'tumbling pigeon DT'.  I've never heard the term.  I'm familiar with the tip up wing DT often seen on TLGs - mine's in the picture below.  If it had an adjustment screw, it would be screwed through where my fingers are with protruding end resting on the main fuselage.  If screwed further through its threaded hole in the 'wing' part of the fuselage, it would serve to jack the hinge apart, increasing the wing incidence relative to the tail.

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mike
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« Reply #13 on: August 28, 2018, 03:48:29 PM »

Thanks guys, hi Norm!  Twice beats not at all!
Fully understand now - thanks.
 
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danberry
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« Reply #14 on: August 28, 2018, 07:39:03 PM »

Note reply from Ram. 

Also from DanBerry.  If we knew your location, we might get you to someone who can save you a lot of frustration.


Literally EVERYONE that I know who flies Free Flight is willing to offer help to anyone.

First-person help is the best.
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Sailaway
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« Reply #15 on: August 28, 2018, 08:40:03 PM »

Hi Dan,I am in western New Jersey almost Phillipsburg, bridge across Easton, Pa. Would love to hook up with FF flyers.  But thanks to all of yu at this site for all the support.
Cheers,
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danberry
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« Reply #16 on: August 28, 2018, 09:14:26 PM »

I am wracking my feeble brain thinking of someone closer than NYC.
Coming up blank so far. Bob Sifleet move away from Pennsylvania. I think.
The field at Wawayanda gets used but that isn't real close to you.
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flydean1
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« Reply #17 on: August 28, 2018, 10:01:38 PM »

Maybe someone from DC Maxecuters is around there.  I think they have a website.  Mostly FAC activity but many have expertise in duration Free Flight (Always Capitalize).
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Tapio Linkosalo
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« Reply #18 on: August 28, 2018, 11:50:37 PM »

entire TE of the wing moves up, however small ( 0.5 degrees or there about) that gives the same effect as up elevator.

"ram" already pointed out that it is "the opposite effect", but let me explain that in more detail. What we discuss here is the angular difference between wing and tail. Also called as decalage. Hence, moving the TE of wing down has the same effect as up elevator.
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Sailaway
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« Reply #19 on: August 29, 2018, 10:58:59 AM »

Thanks Tapio. Understood, So as you see my crude drawing, there is enough room to get the TE down for 0.5 degree or thereabouts "Decalage"  effective "up-elevator).

Dan, i will contact Wayanda club in  NY. great guys i had met up many years ago.
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Re: Adjusting Incidence on a Tumblng Pigeon DT CLG
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Tmat
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« Reply #20 on: August 29, 2018, 02:19:11 PM »

You can get more decalage ("up elevator") by sanding the bottom of the wing mount to give more movement down. If required of course.

Tmat
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USch
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« Reply #21 on: August 29, 2018, 02:31:08 PM »

Appears the 2-56 screw tapped at the TE of the wing will only move the TE of the wing up as the boom is fixed ??

I think you got it completely wrong. The wing has to be firmly glued to the green wiggler in your design. The 2-56 screw can be screwed in or out to push on the tail boom and changes the decalage. If you screw "in" (clockwise) you push the tailboom a little down, same as reducing the decalage. Screw "out" (anticlockwise) you increase decalage.

But thinking it again there is something in your design which sounds wrong. The tailboom cannot be fixed as you write, otherwise how could the Dt work. The tailboom has to move in repspect to the wing the get a decalage of about 30-45° for DT'ing. On your design wing, tailboom and tailplane would move together around the alluminum rivet, leaving the relative position of wing and tailplane unchanged.

Urs

PS: might be total B...S... what I wrote  Huh

« Last Edit: August 29, 2018, 02:52:45 PM by USch » Logged

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mike
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« Reply #22 on: August 29, 2018, 03:21:55 PM »

Urs, the green part, and the wing joined to it, pivot around the rivet to raise the TE of the wing - the model then tumbles down. there's no stable descent like a conventional DT.  It puts the wing into a negative angle stall.
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USch
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« Reply #23 on: August 29, 2018, 05:51:35 PM »

Sorry for that !!!
It was clearly a matter of hitting first the keyboard and then switching on the few remaining grey cells  Grin Grin Grin

Urs
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danberry
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« Reply #24 on: August 29, 2018, 06:42:47 PM »

Thanks Tapio. Understood, So as you see my crude drawing, there is enough room to get the TE down for 0.5 degree or thereabouts "Decalage"  effective "up-elevator).

Dan, i will contact Wayanda club in  NY. great guys i had met up many years ago.

Are you a member of NFFS?
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