Max_Power

Okay..I've actually got back to my bench after way too many "Real" projects. I'm wanting to finish this Herr Texan so that I can start on what will be my first scratch build and own-design plane. I'm at the point where I'm ready to glue the outboard wings to the center section and the plans call for 1.25 inches of dihedral per side. The socket under the tip in the picture is 1 inch tall. This plane will not have moveable rudder or landing gear and will be just a "Yank And Bank" hand toss type job and I'm trying to keep it light and with a HP balance as far as handling. Would you guys run the 2 1/2 inches total dihedral or would you flatten the wing out some?...To what extent Thanks in advance...Todd

Mr Cox

Since it is a low wing I would keep the dihedral.
I haven't flown that particular plane but I would only remove the dihedral on a highwing plane.

BMatthews

First, it'll look really odd with no dihedral. Not much like the Texan at all in flight.

Second a little won't hurt. If one inch is scale then go with it. But certainly no need to add any more than the scale amount.

ChicaWolverina

Even an Ugly Stik, almost anything other than some Jets maybe all look more balanced and real with even the slightest amount of it... dihedral! IMHO!

And it's our friend, without it, it's like a human that's pigeon in-toed trying to dance, metaphorical speaking.

Even the space shuttle does!

combatpigg

My Feedback: (3)

Yeah, low wingers [especially warbirds] look wrong with either too much or not enough dihedral. It lowers the thrust line and vertical CG, bringing it more in line with the heart of the wing. The end result is a better all around flying plane.
The scale amount, [or thereabouts] works just fine.

Max_Power

Fair enough...as long as noone thinks it will adversely affect the aero performance i'll leave it...Honestly I think I may go 2 inches total as I keep setting it up on the table at 1.25 each and it starts to look like a stuka.....But I guess My other HERR kits fly pretty well so mayne I'll just leave it as suggested.

alcarafa

Leave some dihedral or plane will tip stall in no time when speed decrease to much, I would also add at least 1.5 ΒΊ washout to avoid that tendency specially warbirds have .

Max_Power

Well, I ended up at one inch per side and I think it looks good. Weel see how it flies? I'm starting covering on the wing tonight and drilling the engine mount. I need to fix my scale and try to figure out what this thing is gonna weigh. At least its not green and pink...[img][/img]

joshburns7

My Feedback: (1)

I recently finished a Herr AT-6. I built the plane with the recommended 1.25� and it fly’s great.

jeffie8696

Excellent, love the Herr kits.

Max_Power

Looks nice Josh! What is yours powered by? Todd

joshburns7

My Feedback: (1)

Todd,

I powered mine with an AP .061 spinning a wooden 6x3. I used cheap servos from hobbycity. HXT500's for the elevator/rudder/throttle, and a HXT900 for the ailerons. Building washout into the wing tips is a great idea on this little guy. I balanced the Texan right where the plans indicate. I love taking this plane out to the field because hardly anyone fly's 1/2A anymore.

ChopperMike

And neither do you (with this one anyway), .061 isn't 1/2A!

Sorry couldn't resist! Nice model BTW!




Mike

joshburns7

My Feedback: (1)

True, but my norvel's are currently flying other models. Plus I was affraid an .049 would have trouble pulling this guy around. Any progress?

mike526mp

My Feedback: (1)

Rafa,
why would "some dihedral or plane will tip stall in no time when speed decrease to much"? stall is a factor of angle of attack and the airfoil.

Read more: http://www.rcuniverse.com/forum/m_97...#ixzz0sYPleSYV

MJD

My Feedback: (1)

Nice work on that Harva.. er, AT-6 there Josh! Looks great.

MJD

alcarafa

Airfoil is the matter here not angle of attack, it is due to the reduction of wind flow speed that wing loses lift effect in the center of wing first, not at the tip.

In this case due to the geometry of AT-6 wings it looses lift faster, causing airplane more rapidly to enter stall.

Adding 1ΒΊ to 1.5ΒΊ of washout at wing tips helps a lot to avoid this tendency, so marked in this type of wing.

The fact of adding washout will not prevent the wing at any given time to enter in stall, as wind flow reduces its speed more and more wing loses all lift effect.

Mr Cox

I think you are mixing up washout and dihedral a bit...

alcarafa

Mr Cox my first reply was not correctly explained, what I should 've wrote was..add dihedral per plans and add " X " ammonut of washout..... etc.

The effect of washout in this type of wing has proven to avoid tip stall as fast as it could happen without it .

mike526mp

My Feedback: (1)

stall has no relation to the speed of the air going over the wing, a given airfoil has a critical angle of attack, the only thing that can make the wing stall is exceeding the critical angle of attack, washout twists that section of the wing so that section is at a lessor angle of attack, so the washed out/twisted section of the wing is still flying even though the other is stalled.

Big Al-RCU

I agree with all of the above, but unclear what is the effect of dihedral on tip stall? In a yaw or turn, I can see where it is a factor, but what about straight ahead flight?
al

mike526mp

My Feedback: (1)

dihedral has nothing to do with tip stall

fedorsmith

Hey Josh, I realize this thread is a bit old, but your input would be appreciated. How did you build in washout? Did you just block the aft tips of the wings up a bit while you built?

thanks