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A 170 that won't three-point land?!

Posted: Mon Jun 28, 2010 11:24 pm
by FlyingWrench
I am looking at a ragwing 170 that is nice airplane, but has an issue. The owner said that it will not three-point land. He is an experienced T/W pilot, has owned the ship for 7-8 years, put a many hundreds of hours on it and said when he pulls back on the flare it just stalls, and drops the nose, with the mains touching first. He consequently does all wheel landings. A CFI with 1000's of tailwheel hours gave him a BFR in it and he tried to three point it, with the same result. When I looked at the airplane he mentioned it several times. He is puzzled as well.
I have C-140 with 900 hours t/w time. It comes over the fence, I pull it into the three point attitude, flare and it is a non-event. Wheel landings are also a non-event in my ship.
Is this something the ragwing 170's are prone to suffer from or is this an issue with this particular airplane? It had damage history 30+ years ago, but has all the 337's describing the repairs. It was an extensive fuselage repair on the gearbox and door posts.
Any thoughts out there.

Re: A 170 that won't three-point land?!

Posted: Mon Jun 28, 2010 11:36 pm
by sfarringer
I do 3-point landings most of the time in my ragwing.
I don't experience what you describe.
It's pretty common for my tailwheel to touch first ( so maybe that would be a 1-point??? :roll: ).

Re: A 170 that won't three-point land?!

Posted: Tue Jun 29, 2010 12:39 am
by HA
are the wings and tail at the proper angle of incidence relative to the fuselage

Re: A 170 that won't three-point land?!

Posted: Tue Jun 29, 2010 2:15 am
by pdb
Have you correctly computed your CG using proper weights and arms?

Re: A 170 that won't three-point land?!

Posted: Tue Jun 29, 2010 3:13 am
by cmsusllc
Stock engine and prop? Sounds nose heavy to me. I had the same problem when I bought mine ( o-360, no change- Constant speed prop, +20 pounds way out front ) Carry 50-60 pounds in the baggage and tail wheel will touch first. Check the W/B closely and maybe even put it on a set of scales to see where the C/G really is.
Scott.....53B

Re: A 170 that won't three-point land?!

Posted: Tue Jun 29, 2010 3:17 am
by mit
I would have to fly it and see how it does. My 48 would.

Re: A 170 that won't three-point land?!

Posted: Tue Jun 29, 2010 12:00 pm
by Bruce Fenstermacher
My very first thought was the idea is to touch the ground on all three wheels BEFORE the aircraft stalls. 8) OK I suppose you all knew that. :)

So my second thought (but first constructive one) was it's way nose heavy. W&B is where I'd start.

A simple test would be to load it tail heavy and see if it makes a difference.

Next would be to check wing and stabilizer incidence since there was a repair.

Re: A 170 that won't three-point land?!

Posted: Tue Jun 29, 2010 1:24 pm
by johneeb
Are the Elevator stops set Correctly. The proper deflection angles are in the Owners Manual.

Re: A 170 that won't three-point land?!

Posted: Tue Jun 29, 2010 4:20 pm
by FlyingWrench
The 170 is a stock ship with a C-145. There was a wt and bal. for the airplane, but it was one where they had just kept on revising an old one.
My thought was also about the incidence of the wings and tail.
Thanks

Re: A 170 that won't three-point land?!

Posted: Tue Jun 29, 2010 4:23 pm
by GAHorn
johneeb wrote:Are the Elevator stops set Correctly. The proper deflection angles are in the Owners Manual.
I believe John has the most likely scenario. Check the elevator travel limits. For a ragwing they should be:

28-degrees UP, and 17-degrees DOWN, .... AND.... be certain to check elevator cable tensions.... 30 lbs.

Re: A 170 that won't three-point land?!

Posted: Tue Jun 29, 2010 6:03 pm
by wingnut
Never worked on a ragwing, but another possibility is wing washout. If the struts are not adjusted for proper washout, and if you have zero washout, the entire wing would stall at the same time, rather than from inboard to outboard on flare.

Re: A 170 that won't three-point land?!

Posted: Wed Jun 30, 2010 1:59 am
by 3958v
I would think that wash out could cause the problem that is being described. More wash out could lead to the horizontal stabilizer not being as effective in the up position. If my memory serves me correctly the stall characteristics of the superior ragwing airfoil :D did not need wash out. The less superior 170A wing required 1 deg of negative washout and the truly inferior 170B wing needed three deg. :P I guess after this post I better not go to the convention. Bill K

Re: A 170 that won't three-point land?!

Posted: Wed Jun 30, 2010 12:42 pm
by wingnut
3958v wrote:I would think that wash out could cause the problem that is being described. More wash out could lead to the horizontal stabilizer not being as effective in the up position. If my memory serves me correctly the stall characteristics of the superior ragwing airfoil :D did not need wash out. The less superior 170A wing required 1 deg of negative washout and the truly inferior 170B wing needed three deg. :P I guess after this post I better not go to the convention. Bill K
Hey Bill, your right; no twist on the ragwing. I should have checked first :oops:

Re: A 170 that won't three-point land?!

Posted: Wed Jun 30, 2010 5:44 pm
by n3833v
Hey Bill,
We need you to come just to keep us all straight with no washout. :lol:

John

Re: A 170 that won't three-point land?!

Posted: Thu Jul 01, 2010 3:24 pm
by GAHorn
After this post, I think Bill is all washed-up! :lol: