I wonder how many of the stall spin accidents we hear about happening to seasoned pilots can in part be attributed to out of rig aircraft.

It appears to me as we become more skilled we overcome flying discrepancies, an attribute some of the aircraft's quirks to being the nature of that aircraft.

Awhile back I flew a friends aircraft that he thought flew pretty well. He is a seasoned crop duster pilot.

The wings were so unsymmetrical that as I approached a stall I found myself using a lot of left rudder to keep it from yawing to the right.. This aircraft had over 5 degrees of wash in on the right and seven on the left. It should have one degree, which with loading causes it to theoretically be set at zero. One flap was also low.

After a day of measuring marking and re-rigging it fly's totally different.
The nose stays straight, it just mushes in the stall. And a spin entry is quickly stopped in either direction by normal recovery techniques. With very little rudder needed to keep the nose straight.

I cant help think that any average pilot could have never recovered this
aircraft from a inadvertent spin entry and the results would have been catastrophic.

I just had my Maule rerigged and picked up almost 5 mph in cruise! So, besides the safety aspect, there is a fuel savings to! It would seem like inspecting the rigging should be on the checklist for the annual.

Scout,

I stall every airplane I'm going to fly more than one trip around the patch. I don't give a darn what the owner says. I've had guys tell me how they blow every Super Cub off the planet when it comes to short field work, then gone up to 3,000 and stalled their airplane straight ahead, ball centered and got to 1.5 turns before I could get it sorted out.

"Some" factories, put out mis rigged aircraft with some regularity. I'd re-rig every rag and tube airplane if I bought it new.

Just because you have a little experience is no reason to take for granted the stall characteristics of an airplane. I've seen some ugly stallers of types that are famously gentle in the stall, and these were too, AFTER they were rigged right.

Also, beware of pilots and mechanics who tell you they have a "special" rigging technique for their airplane. That is almost always a disaster waiting to happen. The factorys know how to rig their aircraft-follow their rigging protocols.

And, read Rich Stowell's new book on stall spins. It will help to understand the importance of this stuff.


MTV

Mr Scout-

I think you have a good point. When I bought my 170, it flew hands off in about a 30 second turn I had to hold left aileron and right rudder to fly straight and level. Turned out to be a combination of the eccentric bushings at the rear carry-through spar wing attach point, as well as aileron push/pull rod length which was adjusted with the turnbuckle. That's about all you can adjust on a stock Cessna wing. Rag and tube wings have their washout dialed in with cable tension, right?

I fixed it before I did any stall practice in it in that condition, but I think it might have been a little scary. Trouble is, I evened it up with the trailing edges a bit low, so I'm sure my cruise is less than optimum now.

mtv wrote:And, read Rich Stowell's new book on stall spins. It will help to understand the importance of this stuff.
MTV

I just saw a reference to this book as being something like 500 pages long. How did he get 500 pages on such a narrow topic?

tom

mtv wrote:
Just because you have a little experience is no reason to take for granted the stall characteristics of an airplane. I've seen some ugly stallers of types that are famously gentle in the stall, and these were too, AFTER they were rigged right.
MTV

My point exactly, I think there are a lot of pilots that think if it happens to them they can recover, when in fact the aircraft itself may be unrecoverable no matter what there level of expertise, due to poor rigging.

zane wrote: ... Rag and tube wings have their washout dialed in with cable tension, right? ....

Zane, you adjusted your 170's angle of incidence with the eccentric rear spar attach eccentric bushings.The washout is built into the wing when it is skinned.
Most tube & fabric airplanes have V wingstruts. The spar attach points are fixed. You adjust the AOI of the outboard end of the wing at the upper end of the aft strut, which changes the washout (twist) of the wing.

Eric

zero.one.victor wrote: Zane, you adjusted your 170's angle of incidence with the eccentric rear spar attach eccentric bushings.The washout is built into the wing when it is skinned.
Most tube & fabric airplanes have V wingstruts. The spar attach points are fixed. You adjust the AOI of the outboard end of the wing at the upper end of the aft strut, which changes the washout (twist) of the wing.

Yes, I learned that this last summer during the Great Enlightenment of Cessna Mechanicsmanship (1st annual.) When people would talk about rigging their wings, I always thought they were talking about adjusting the washout, but all the metal wing has after being built is AOI. Nudging the neutral aileron position helped a lot too.

Savannah Tom,

The simple answer is that this is decidedly NOT a narrow subject.

Get it, read it.

MTV

Well said, everyone! I'm just finishing up an "annual" (more like a restoration, almost!!) on a SuperCub that an "expert" pilot had owned and declared "a fantastic Cub".... it was SO far out of rig, it was pathetic!! WAY too much dihedral, totally uneven wings, ailerons at different angles, flaps at different angles, tail feathers twisted....... it's been a total mess!! I asked the last guy that flew it, how it flew and he said it was "fine"...but when I questioned him a bit further, he said, "oh yeah..it DID dive off to the left when you let go of the stick.." He also mentioned that in turbulence it really had a tendency to drop a wing... That's FINE?????? There's much more to an annual than cleaning plugs and signing the log books... if you're getting a $300 annual, you're most likely (not always) getting what you're paying for.... think about it.
The thread on minimum radius turns should get everyone thinking...what would happen if you get into a situation that you had to do a max performance, minimum radius turn???? Is your airplane rigged right, so it can fly predictably and do what you need it to do now???? I'd hate to find out a little too late!
Like MTV said, "The simple answer is that this is decidedly NOT a narrow subject."
JH