Questing regarding lifting horizontal stabilizer. - Page 2

rocketman1988 · #11 10-25-2018, 06:00 PM

You also need to realize that the aerodynamic loads are distributed loads across the area of the stab. Lifting at two discreet points would act more like point loads.

Yes, you could argue that the ~75lb was distributed across the surface covered by the hands but that area is far less than the area of the stab.

I also think you are probably fine. This is mainly for discussion's sake.

Also, I had a 1957 C-172. On the last annual, we found a crack running from the edge of the center lightening hole in the forward stub spar of the horizontal stab. After some research, we found that this was not uncommon, there was an approved FAA mitigation, and the likely cause was pushing the tail down to raise the nose gear and move the airplane.

kismet · #12 10-25-2018, 07:31 PM

Bummer that this happened, but it seems nothing was tweaked or otherwise damaged. I'll keep an eye on things and likely won't experience anything catastrophic as I fly within the Utility Category (waiting and saving my pennies for a Giles...) and inspect fairly often.

If something does happen, that tow guy will sure feel bad as I did give him some grief over just picking the ****ing plane up. More strength than sense in that guy.

sblack · #13 10-25-2018, 07:49 PM

If 75 lbs was going to damage your stab you would have crashed a long time ago. But he still should NEVER touch a plane anywhere without asking. I have seen guys scared to pull on their prop, not thinking that it yanks the plane around the sky with 100s of lbs of thrust. People don't generally have a feel for the loads on the various parts of an airplane.

Scott Hersha · #14 10-25-2018, 07:51 PM

If you want to ease your mind about this, go up and do some stalls - after you?re sure there?s no deformation or cracking....... better yet, go up with someone else in their RV, any RV, and have them hold the plane in the stall after the break. Keep the wings level with the rudders, and have a good altitude margin. While holding it in the stall, take a look at the HS. That thing shakes like a wet dog. The first time I saw this was with Bill Benedict in the RV8. It looked like the tail was going to come off - and they do this demo countless times to show how controllable the airplane is even in a stall. That tail plane moves up and down, rapidly, and it?s a noticeable amount. It?s designed to handle these kind of loads.

That being said, I know you won?t allow anyone to help move your airplane in that manner again. Hand pressure in the wrong place can deform the skin, bend a rib flange, and put shear stress on , or loosen rivets attacking the skin, which of course carries part of the load. If you can?t see anything wrong, I?m sure you?re fine, but check with the experts in Aurora to be sure.

xavierm · #15 10-26-2018, 08:57 AM

People almost always want to help with something when you are giving someone a ride. I always let them know that I will move the airplane myself
and/or give them something to do before they find something to do to be 'helpful'. Watching to make sure I don't hit anything when pulling the airplane out, or pushing it back in the hangar is a good 'stay out of the way and be helpful' activity.

kismet · #16 10-26-2018, 10:21 AM

Yup, he's the 20th or so passenger I've flown with. Usually they are obedient but since he's finishing A&P school he probably had the confidence to go ahead and lift the tail. Bold move, though.

kismet · #17 10-26-2018, 10:29 AM

Not a good idea, but shouldn't hurt it. They lifted their RV-6 with Mike Seager, except with two folks: one one either side lifting with two hands at the inner and second-to-innermost nose ribs.

Time to let it go and wait for the next ding to occupy my mind. This is all hopefully increasing my intestinal fortitude for when my time to build comes up.