question for matt

[harv]

hi guys. i was just wondering, does the full scale cap 232 have dehedrial in the wing or is it flat(no dehedrial)??
\




harv

[TonyThomasian]

It looks like it does have dehedrial.... from looking at these pics.... http://www.france-voltige.org/Photos/cap232_paris_1.jpg

http://pierphoto.free.fr/galeriesgen...col/_00003.jpg

http://www.nak.no/motor/foto/cap232-stor.jpg

[harv]

it looks like it does, but very little.

[maeu2003]

its weird seeing my name in the title of a thread. i kinda freaked seeing it.

[Matt Chapman]

the wing has what is called a double taper.
the wing gets thinner towards the tip, so the taper is what is making it look like dihedrail, but the top of the wing is flat across, and the bottom wing comes "up" . Kind of like buildinga wing up-side-down flat on the board. Does that make sence?

[Rolling Thunder]

The wing on the Midwest Cap and Extra are built just like that. I believe the radiowave 300 is also this way.

[Judge]

	Quote: Originally Posted by Matt Chapman
	the wing has what is called a double taper. the wing gets thinner towards the tip, so the taper is what is making it look like dihedrail, but the top of the wing is flat across, and the bottom wing comes "up" . Kind of like buildinga wing up-side-down flat on the board. Does that make sence?

Most all pattern planes back in the 60's and 70's were built the same way. We called it "effective dihedral". Built them just like Matt says, upside down on a flat board.

[Toro]

	Quote: Originally Posted by Judge
	Most all pattern planes back in the 60's and 70's were built the same way. We called it "effective dihedral". Built them just like Matt says, upside down on a flat board.

Bill,

you remember the 60's ?

love ya...

[teryn]

[airfoil] "thickness taper" is what you are referring too (proper terminology). the other taper has to do with the chord.

Dihedral produces a rolling moment in the presence of a sideslide. I am surprised that there is no dihedral on this plane. I wonder if thickness taper still contributes to the dihedral effect.

	Quote: Originally Posted by Matt Chapman
	the wing has what is called a double taper. the wing gets thinner towards the tip, so the taper is what is making it look like dihedrail, but the top of the wing is flat across, and the bottom wing comes "up" . Kind of like buildinga wing up-side-down flat on the board. Does that make sence?

[Matt Chapman]

Dihedral make the plane more stable. Something we don't want in an aerobatic plane. Keep in mind we also fly inverted and ou don;t want to be fighting dihedral while inverted.
On a Cessna the dihedral will allow the rudder to keep the wings level and even roll in and out of turns. On a CAP, Extra, Suke ect. you can't, nor do you want to do that. However; on Extra's, a certified plane the spades are tipped. This will creat a slight movement in roll giving you the ability to keep the wings level, or get out of a spin and return to level. (required for FAA certification)
Just some basic info for those who care.
MC

[teryn]

Matt, you are correct. I thought that there would be between 0 and 1 deg at least to offset the roll instability due to the CG being above the wings. Most low wings have this, but of course we don't want the plane to be too stable for aerobatics. Interestingly, the bigger airplanes like the C-5 and C-17 have anhedral in their wings. The purpose of this is to damp out the so-called Dutch Roll mode instability found on some high wing airplanes.

Are the spades those shovel like things that hang down below the wing? I understand that those add a boost to help the pilot move the ailerons udner demanding circumstances.

[Matt Chapman]

Yup, the "spade" or "shovel" are a form of "power steering" Without them on my plane at red line (240mph) the stick is very heavy. Two hands needed to move it, and only a little is possable. The way my plane is set up, I can move the stick all the way to the stop at red line with just one finger. I have a strong center, but that is easy to get through, and once out, the rest is very easy. The plates are used to assist in stick forces and centering. By changing the incidence on the plate you can change both stick force, stick centering, break out force and even roll rate. Set them up wrong and you can really have your hands full in the push, or negitive "G".

Again, just my 2c....

[teryn]

I LOVE this. I've participated in two recent threads here, this one included, with real, useful, relevant information coming from knowledgable people (who know what they are talking about), not contaminated with conjectures and baseless information. What a breath of fresh air! It is such a pleasure...

wow, I didn't know they were that important and useful. Always wondered, thank you.

[harv]

	Quote: Originally Posted by Matt Chapman
	the wing has what is called a double taper. the wing gets thinner towards the tip, so the taper is what is making it look like dihedrail, but the top of the wing is flat across, and the bottom wing comes "up" . Kind of like buildinga wing up-side-down flat on the board. Does that make sence?

yup, makes scence, ill have to take a look at my lanier and see how it is. hehe.

when flying aerobatics full scale, are the g forces like riding a roller coaster, or higher.

[Matt Chapman]

Teryn....hold on now...please don;t confuse me for a person that knows what their talking about!!
The spades are sometimes also used for dynamic balancing in conjunction with the above issue. My plates are REQUIRED for flight due to balance. If you take off the control pushrod, my airlerons will balance a little leading edge down... 110% balanced. Without this, you could expect control flutter at higher speeds.
more usless information!!
MC
ps...and glad to be part of a useful/interesting thread.