Wing dihedral?

[Paul Taylor]

So I’m flying a Hangar 9 PT 19 to get reacquainted with the stunt pattern after a Hiatus.
This is the first plane I have flown with dihedral. It might be the lose nut at the handle but it seems this plane drops like a brick after engine quits and does not “float” in. Could this be a result of the dihedral?

[Dan McEntee]

So I’m flying a Hangar 9 PT 19 to get reacquainted with the stunt pattern after a Hiatus.
This is the first plane I have flown with dihedral. It might be the lose nut at the handle but it seems this plane drops like a brick after engine quits and does not “float” in. Could this be a result of the dihedral?

   I haven't flown mine in a while and it needs a recover job, but I recall that it had the glide angle of a large , flat stone! dihedral doesn't affect glide, only stability. Lots and lots of model airplanes and full size aircraft have dihedral and polyhedral and they glide quite well, some even thermal! It's got dihedral in the wing to get the lead outs up to the vertical CG position so it will track correctly in level flight, because the wing is so low in the fuselage

  Type at you later,
   Dan McEntee

[Dennis Toth]

Paul,
Usually, if they drop fast after the power quits it is nose heavy. Try a little clay on the tail and see if this helps. Some ships even if the CG is per plans need additional fine trimming to get the smooth power off glide. Other thing to check is that there is no upthrust in the engine/motor alignment.

Best,   DennisT

[Ken Culbertson]

There is much discussion about the vertical CG.  I am not asking about it's importance, I get that.  But I am at a loss as to how to find it!

Ken

[Jim Hoffman]

There is much discussion about the vertical CG.  I am not asking about it's importance, I get that.  But I am at a loss as to how to find it!

Ken

Assuming no dihedral.
Hang it by the leadouts
Use a plumb bob or a laser to define vertical.
Stand in front of the airplane.
Looking at the LE from the nose.
Compare center line of LE to gravity.
Adjust vertical CG or leadout exit until leading edge is parallel to gravity. 

[Ken Culbertson]

To find vertical CG, hang the model by it's lead outs and use a plumb to check for a true vertical.  Usually all it take to correct this is by moving the lead outs (the slider actually) up or down in the tip, so it hangs straight.

Thanks, I am headed for the shop now.

Some will see the humor in this but the vertical adjustment of the leadout slider is the one thing that I have never made *adjustable*.  For that you need a surgeon, or maybe just heavier wheels!

[Jim Hoffman]

I have seen leadout guides with vertical adjustability.

It was on a high end war bird stunter with dihedral

[Steve Helmick]

I'd say it's CG or flap related. IF the flaps are UP with the elevators NEUTRAL, it's the flaps!  Steve

[Paul Taylor]

This is the Hangar 9 ARF. No flaps.
I did have to add nose weight to get it to settle down a bit. I just took a SWAG at the CG. I have no planes so not sure where it should be. 😜

[Steve Helmick]

This is the Hangar 9 ARF. No flaps.
I did have to add nose weight to get it to settle down a bit. I just took a SWAG at the CG. I have no planes so not sure where it should be. 😜

Ahhhh....I've never seen a Hangar 9 ARF out here. Didn't know they were flapless. How about that!  Steve

[Ken Culbertson]

I have seen leadout guides with vertical adjustability.

It was on a high end war bird stunter with dihedral

If they it was horizontally adjustable as well and fit into the wing,  I am interested to see what they look like.

Ken

[Steve Helmick]

If they it was horizontally adjustable as well and fit into the wing,  I am interested to see what they look like.

Ken

Paul Walker had vertically and horizontally adjustable L.O. guide on his Miss America P-51 Mustang. Saito era stuff...about Y2K. I don't recall studying it, but I'd guess that there were vertical slots at each end of the slide plate to allow raising the whole plate. Last I saw, he went back to the old "eyelets in holes with a slot between just big enough for the leadouts scheme". But you never know what that guy will try next!  Steve

[Dennis Toth]

Paul,
CG for non-flapped ships is generally around 15 -18% of the average wing cord back from the leading edge at the average cord (you can project this over to the root to make balancing easier). Ted Fancher had a general rule that the starting balance point is whatever % the tail area is of the wing area back from the leading edge of the average cord.

Best,   DennisT

[Paul Taylor]

Thanks I will see if I can adjust the CG.
Not much I can do about adjusting the leadout. 😫

It’s the yellow plane in the photos.

PS- If anyone every saw Dan and Mike flying two up doing the pattern at Brodak’s those were the same plane.

[Chris McMillin]

Paul,
Lead it with your flying hand to a slight descent as soon as it quits and fly onto the ground with a little speed, it's a draggy model being a profile and the lines and stuff need energy to keep going. The floaty model landings you see are really guys slightly whipping it to a nice smooth landing. If worried about a rough field, stop leading it when it is one inch high and let it slow down there, not at 8 feet or something. They are tethered vehicles, like powered kites, your handle actions do make a difference.
Chris...