How important is the wingtip washout on the Great Planes PT-20? Can it be flown accurately and safely without this washout?

A straight wing like on that trainer is resistant to tip stalling anyway. So yes, if it's built flat it will fly fine.

I agree, don't worry about it

I disagree, build the wing as intended, It is what gives the airplane its delightful flying characteristics.

Yes the washout seems considerable but the very simple step to apply it during construction spelled out on the plans is easy and should not be left out unless you want just another OK but not so nice flying small trainer.

Here is my PT-E which is a slightly lightened version of the PT-20 which I built dunno maybe eighteen years ago as a first more or less modern electric. I still fly it a few times a year and its wonderful albeit with a much improved outrunner.


John

+1

Don't modify unless you really know what you are doing. The designers of these planes test and modify them to have them to fly so the average pilot can handle them. When we start to modify them for looks or what ever, it starts to change the behavior on how the aircraft operates. When ever I took a ARF, Kit or RTF and made changes to make it more scale looking, I can say that about 70% of the time my planes became a little harder to fly.

If you're a new pilot, I wouldn't do it. If you have a hand full of years in this hobby and you want to experiment- go for it. And if it doesn't fly well then I'd redo the wings the way the directions wanted you to have them in the first place. JMHO


Pete

I'll take the middle position... if the wing is all ready built without the washout... go ahead. If it is yet to be built, follow the plans and include the wash out.

I'll go that route too. If you're just looking to save the step of putting in the washout, then go ahead and build it like the manufacturer suggests. But if the wing is already framed up and you forgot to do it, don't worry about it.

Hi MinnFlyer,

We've taken different positions on washout in the past...

http://www.rcuniverse.com/forum/m_92...tm.htm#9339065

My position comes from owning two fairly similar Cubs (Goldberg Anniversary and World Models) and a 1.20 size Taylorcraft. The Goldberg (kit built with generous washout) is the far superior flier compared with the World Models (ARF, having no washout) in regards to potential for tip stalling. The Goldberg will practically not tip stall whereas the World Models had a nasty history of it.

The World Models was tamed somewhat by adding simulated washout by trimming the barn door ailerons up slightly at lower throttle settings. The trim adjustment has kept the plane off the rebuild bench. The same is true for a Taylorcraft... the simulated washout reduces its tip stalling character.

Washout is a great tool to produce better flight manners (greater tip stalling forgiveness) for planes that generally are not asked to do outside maneuvers. For the experienced pilot who is generally aware of his flight window, washout might not be of significant value... but to those who might struggle to be attentive to that flight window... washout can be a savior.

That washout is the difference between being able to wheel a low/slow deadstick into the wind and not stall or having to take what you can get.

Even full scale F-16's and F-15's have washout, so I think it may have a lot of benefit that far outweighs the slight penalty's. If you can put it in, then put in what the instructions specify.

Full scale Cubs have washout.

I've had constant chord wings that were excellent without washout, but since it's for training, I'd go with the experience of the guy who has one and use the washout.

This plane already has a fairly stall resistant airfoil and light wing loading. Sure, the washout will reduce any tip stall tendencies even further, but it's not like the thing is going to snap sideways on a landing approach without it.