tonyc

My Feedback: (4)

I looked at the specks for the GP Pitts and the GP Christen Eagle. The Pitts has 0 degrees top wing incidence and the Eagle has +5. Is that right?

I thought that they were basically the same planes.

tonyc

Flyfalcons

Found the specs, kind of odd. Not sure if that is by design or a typo - I don't have my wings together yet so I can't verify it. I don't think they would make a change like that without reason.

deputydog

The difference in incidence between the wings is like adding toe in on the LG. It makes the plane fly straight. I too have not gotten that far on mine yet. i'm still waiting for a new top wing from Tower![&o]

JLB

My Feedback: (2)

Where did you find the specs?

Tired Old Man

My Feedback: (1)

Something is really wrong here. I've been flying bipes for about 30 years now and +5 on the top wing is unheard of. If the tail plane is at zero to 2 degrees negative or positive, and the bottom wing is at zero, there is no way that the top wing should be at +5 degrees.

Set up with the positive, it will probably pitch hard to the canopy in knife. It may help some with slowing the plane for landing, but I don't know if the trade off would be worth it.

I would certainly get in touch with Great Planes to confirm the incidence parameters.

Texas 3D

My Feedback: (16)

has anybody contacted Great Planes about this ? What is the latest status on this ?

Flyfalcons

I sent an email to Great Planes about it, plus a minor manual correction. I asked if it is a typo, and if it isn't then why it was changed from what the Pitts had. Hopefully they'll come back sometime today.

Airbike

My Feedback: (6)

Hiya,
What specs are you guys refering to?
I've looked over the manual but didn't notice anything regarding setting up the wing incidences. Basically, it said that the cabane and interplane struts would set the incidences correctly if assembled per instructions.
I haven't started assembly yet so I can do any mods required.
Ryan, any reply from GP?

Flyfalcons

I got an automated reply but followed the instructions on getting a human to read my question, since it wasn't answered in the automated reply.

Here is where I found the specs:
http://www.gpmd.com/cgi-bin/wgpinf100p?&I=GPMA1217

basmntdweller

My Feedback: (9)

Just a guess, But I'd bet they accidently left out a decimal point. i.e. 0.5! My past experience with biplanes would suggest that the wing incedences are reversed as well. I'd want the top wing at -1.0 and bottom wing at +.5. This would then be like toe-in on a car. As specified it's more like toe out.
I'd be curoius what GP says if you ever get a direct answer.
Later,,,basmntdweller

OVER WORKED

I don't work for Great Planes and as such take this for what it's worth. For biplanes that have a positive stagger, adding incidence to the top wing assures it will stall first. This is very important since the center of lift for the front wing will be far ahead of the C.G.. If the bottom wing was to stall first and the top was still flying such as in a flair for landing, the result would be unpleasent at best.

tonyc

My Feedback: (4)

The +5 is from Tech notes at Tower hobbies. Here it is directly quoted.

Incidences: Stab: 0 degrees
Bottom Wing: -1
Top Wing: +5
Engine: 2.5 degrees down, 1.8 degrees right

The reason I would like to know is that I am starting on a scratch built Eagle form Pilot plans. Almost the same size is the GP Eagle.

Except for the +5 degrees they look to be about the same.
Is the 2.5 degrees down on the motor ment to off set the +5 on the top wing?

I bet its a 1/2 degree + on the top wing.

tonyc

Bax

My Feedback: (11)

We did some checking. There's a "typo" in the tech notes. Correct incidence for the top wing of the Great Planes Christen Eagle should be +0.5 degrees.

We'll make sure it's corrected.

Texas 3D

My Feedback: (16)

Great !
Thanks for clarifying this Bill