Waco wing incidence?  
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Waco wing incidence? - 1/24/2004 12:30:27 PM   
Xrod



Posts: 204
Joined: 11/26/2003
From: Eglin AFB, FL, USA
Status: offline 		I am building a 1/6 Pica Waco and plan to buy an incidence meter to check my setup. The manual does not mention what these numbers should be so I measured directly off the plans and this is what I came up with. Top wing -2 degrees, bottom wing -1 degree, horizontal stab +1 degree. Can this be right? I thought that the top wing should have a greater positive incidence to stall first. Can anyone shed light on this? Can any builders of the Pica Waco tell me what numbers have worked well on thier models? Thanks in advance for any help. Planning to post this under "aerodynamics" as well.
       Post #: 1

RE: Waco wing incidence? - 1/27/2004 2:55:24 AM   
Eddie Fowler


 

Posts: 7
Joined: 11/1/2003
From: Landrum, SC, USA
Status: offline 		Wing Incidence for the waco should be 0 to +1 degree bottom wing.
+1 to +2 degree top wing
1 to 2 degree positive stabilizer
All in reference to the top crutch of the Fuselage being level

I just had to get pica to verify these specs for mine.

hope this helps.

Eddie

< Message edited by Eddie Fowler -- 1/29/2004 10:57:12 PM >

(in reply to Xrod)
       Post #: 2

RE: Waco wing incidence? - 1/27/2004 9:16:54 AM   
El Kapitan


 

Posts: 31
Joined: 6/13/2003
From: Basildon, UNITED KINGDOM
Status: offline 		hi
we have a PICA Waco that is partially finished & has been, shall we say, messed up slightly by the previous attempts to build. we have the manual, but no plans. everything's built (just not necessarily in the right way!)- it just needs putting together and finishing. if someone has a copy of the plans could they take some digital photographs and email them on - many thanks

kevin

(in reply to Eddie Fowler)
       Post #: 3

RE: Waco wing incidence? - 1/27/2004 12:39:37 PM   
BobH


 

Posts: 4420
Joined: 4/1/2003
From: Springfield, VA,
Status: offline 		Why don't you contact PICA and buy a set of plans direct from them? Just wondering..

(in reply to El Kapitan)
       Post #: 4

RE: Waco wing incidence? - 1/27/2004 7:59:42 PM   
Xrod



Posts: 204
Joined: 11/26/2003
From: Eglin AFB, FL, USA
Status: offline 		OK now I am confused! Eddie, thanks for your response. I posted this under another forum and got this response:

Xrod, Because nobody answered this for you I thought I would. As you may or may not know I just finished the design of a 1/5 scale Waco for Kangke, and the wing incidences you list are correct. It's important to have both wings carry about the same loading and with the large stagger of the Waco a couple of problems arise. The upper wing is larger than the lower and the lower wing is in the down wash of the upper, this helps keep the flow over the lower wing. To get them both to stall at approx the same time neg incidence is used in the upper wing. This problem is compounded by the fact you have an under-cambered airfoil {yes a clark Y is under-cambered }. If you use positive incidence in the upper wing it will carry so much of the load that the lower may not do anything, it also has the same effect as moving the C.G. back because you moved the center of lift forward. You will also find that too much positive incidence in the top wing will cause SEVERE pitch coupling to the belly when in knife edge.

_____________________________

Ray Nano
Kangke / Super Kraft / TSI
Tech support. Design team

My measurements were directly off the plans, and thats where I came up with the negative incidences. What do you guys think?
Steve (Xrod)

(in reply to BobH)
       Post #: 5

RE: Waco wing incidence? - 1/28/2004 8:31:10 AM   
El Kapitan


 

Posts: 31
Joined: 6/13/2003
From: Basildon, UNITED KINGDOM
Status: offline 		typical modeller trying to save money. as most of hthe plane is built we don't need accurate plans - so some pics of the plans would be acceptable to aid finishing

thanks

kevin

(in reply to BobH)
       Post #: 6

RE: Waco wing incidence? - 1/28/2004 9:37:03 PM   
OVER WORKED


 

Posts: 145
Joined: 2/11/2003
From: Deer Park, NY, USA
Status: offline 		If you use +2 degrees of pos incidence in the top wing and set the C.G. at 30% MAC, you are going to get knife edge pitch coupling to the gear that may be so severe, it may be uncontrollable with full rudder. This coupling will also happen in level flight, and that should make rudder corrections when landing very interesting.

< Message edited by over worked -- 1/28/2004 9:36:45 PM >

_____________________________

Ray Nano
Kangke/ Super Kraft/ Brison, Tech support/Design team

(in reply to Eddie Fowler)
       Post #: 7

RE: Waco wing incidence? - 1/30/2004 3:32:53 AM   
Eddie Fowler


 

Posts: 7
Joined: 11/1/2003
From: Landrum, SC, USA
Status: offline 		In this discussion there is one factor overlooked. This is the design of the original manufacturer and vintage of the kit being built.

This being said there are many airfoil sizes or ratios if you will, which fall into the category of Clark Y.

With this in mind one would need to refer to the drawings and specs for the specific revision of the model being built.

Also as a note if Model aircraft were built with an exact scaling of the airfoil of the full scale plane over 80 percent of modelers would be unable to fly them.

The figures given to me from Pica is specific to the model vintage of the YMF 3 which I built.

In flying my model I have the ability to fly at thirty to forty percent power with full up elevator and the use of rudder stop to stop wags the tail no bad tendacies to go crazy on me.

The rudder applied at full power full left slip or full right slip is managable with less than half aileron. there is no abrupt dive or climp moves in dive or in recovery of dive. So if there is something wrong with the setup I wouldn't want to fix it.

Rather than discuss probabilities and possibilities with someone who is asking for help on their problems, I guess the best solution is for them to get the best information from the company that actually kitted their airplane.

Didn't mean to get into a theory match on this one guys. Just tried to help modelers with a bit of info I just had to acquire for myself from the company who kitted mine.

Hope anyone who needs the factory specs for the Pica one fifth scale Waco YMF 3/5 non laser cut kit can use the info.

In most instructions for building models you will see a disclaimer that the prints may vary due to folding or due to atmospheric conditions, it explains that they are to be used as an outline or guide. there are very few prints made from a grade of paper as that of archetectural drawings and the stability is just not there. There are in most cases instructions telling you to sand and fit the wings after assembly in the wing cradle to achieve correct fit or incidence and then fit the bolt down fitting in the fuse at that time.

This should tell you that the incidence should not be measured by the prints but the technical data given in the instructions should be followed to get the proper angle for the flying surfaces as well as the engine thrust line.

If you notice my first post I had only included the setup which had worked out best for my model. You now look back to it you will see I have edited it to include the exact content of the measurements given to me by Mr. Jon Tanger of Pica Enterprise Inc. Miami Florida.

If you need to contact someone at the factory He has been a good source for me.

Best wishes to all

Eddie

< Message edited by Eddie Fowler -- 1/30/2004 10:13:33 PM >

(in reply to OVER WORKED)
       Post #: 8

RE: Waco wing incidence? - 2/4/2004 8:21:51 PM   
Xrod



Posts: 204
Joined: 11/26/2003
From: Eglin AFB, FL, USA
Status: offline 		Gentlemen,
As a follow-up to this thread, I wanted to let you know that I spoke to Jon at Pica Products for clarification of the wing incidence. He stated that the wing incidence should be 0 deg for the bottom wing, 1 to 2 deg for the top, and 1 1/2 deg for the horizontal stab in relation to the crutch. He also said that it should be measured outboard (he said at the W6 rib) of the center section because of the, for lack of a better word, a ducks a** profile on the center section of the wing. Since I used the side view plan to take my measurements, and went with the center section, this explains my faulty measurements. He also said that it's not that critical because the measurement is dependent on how one sands the leading edge. I'm happy to have a solution now, and want to thank everyone for their input.
Steve

(in reply to Eddie Fowler)
       Post #: 9

RE: Waco wing incidence? - 2/4/2004 10:32:09 PM   
TomCrump



Posts: 2243
Joined: 4/7/2003
From: Traverse City, MI, USA
Status: offline 		Steve,

Thanks for the followup. Ive been watching this thread with interest as I have the 1/6 WACO that I will be starting soon.

_____________________________

Tom C

(in reply to Xrod)
       Post #: 10

RE: Waco wing incidence? - 2/5/2004 2:57:16 AM   
Eddie Fowler


 

Posts: 7
Joined: 11/1/2003
From: Landrum, SC, USA
Status: offline 		Steve

I wonder ?

Is your waco a newer Kit?

Is It Fifth Scale?

And I wish to Know the flying traits of the model when you complete it.

The settings are in the same ballpark as mine in the wing settings but the stab settings
are just oposite of what they emailed me for mine.

Mine flys beautifully and the reason I questioned this is because of your listing as negative on the horizontal stab. They instructed me positive and I am flying with no elevator trim in level flight.

I even went back and checked the original email again just Now.

Wonder what the difference is.

Thanks

Eddie

(in reply to Xrod)
       Post #: 11

RE: Waco wing incidence? - 2/5/2004 3:50:36 AM   
BobH


 

Posts: 4420
Joined: 4/1/2003
From: Springfield, VA,
Status: offline 		Eddie, Im not sure but I believe you mis-read Steve's post. He said 0 for the bottom. 1-2 neg for the top and 1 1/2 for the stab. I believe he means that to be 1 1/2 pos.. and only neg for the top wing.

(in reply to Eddie Fowler)
       Post #: 12

RE: Waco wing incidence? - 2/5/2004 4:05:57 AM   
TomCrump



Posts: 2243
Joined: 4/7/2003
From: Traverse City, MI, USA
Status: offline 		Upon rereading this thread, it looks to me that Eddie and Steve have stated pretty much the same numbers.

It looks like Pica is using the same settings for both the 1/6 and the 1/5 scales.

This, of coarse, supposes that I read it correctly.

_____________________________

Tom C

(in reply to BobH)
       Post #: 13

RE: Waco wing incidence? - 2/5/2004 4:37:50 AM   
Eddie Fowler


 

Posts: 7
Joined: 11/1/2003
From: Landrum, SC, USA
Status: offline 		Tom

in re-reading steves post I found that I had read the word deg as neg, I guess I am overworked and I am sorry for looking so stupid in my last post.

Will try harder to comprehend what I read before I post from now on.

Thanks guys

Eddie with dislexia

< Message edited by Eddie Fowler -- 2/5/2004 9:12:25 PM >

(in reply to TomCrump)