Rigging

tshort · Post by **tshort** » Wed May 23, 2007 3:11 am

I have noticed that while in level cruise flight, my elevators are deflected nose down - significantly.
Enough that the "leading edge" (the outboard portion at the front) of the elevator is probably 3/4-1" up.
Can rigging be done without wrecking the fabric on a '48? My covering is only 3 years or so old and I hate to do anything that would wreck it. I'm not sure if it is a stabilizer incidence issue, wing incidence issue, both, etc.

Thoughts?

T.

15A · Post by **15A** » Wed May 23, 2007 3:27 am

How much weight was in the plane???

Post by **GAHorn** » Wed May 23, 2007 3:45 am

Thomas, this is a common condition on 170s and should be considered normal, depending upon aircraft loading, of course. Mine does exactly the same thing. Don't waste too much time on it.

Post by **Bruce Fenstermacher** » Wed May 23, 2007 1:04 pm

The answer to your fabric question is that the amount of rigging change you may do SHOULD NOT effect the fabric. Now I'm going out on a limb a bit here because I don't know what fabric or paint process was used. But bottom line if there is an issue you probably shouldn't be flying it.

What I mean by this is the paint and UV protection gets brittle as it ages which takes more than 3 years or there is problem. Also you would be amazed how much your wings and fabric flex during normal flight.

I agree with the proceeding comments. Your rigging is probably fine. I would do a weight at balance for the loading you had and see where the CG was. I'm thinking a bit to the rear of the aircraft.

I'm not familiar with how wing rigging on the '48 is accomplished but if you did anything you would need to raise the trailing edge of both wings for the same loading you where running.

Of course if you had an A or B this is accomplished with the eccentric bolts at the trailing edge of the wing. And according to the service manual the eccentrics should be centered unless correcting for a heavy wing.

You only need to make sure your aircraft is with in spec.

tshort · Post by **tshort** » Wed May 23, 2007 2:52 pm

I doubt it was in an aft CG range - there was all of 150lbs of me in the airplane and that's it.
This may be something for us to look at during the annual this year ... I'll talk it over with the mechanic.
Where do I find info on how the airplane should be rigged? i.e. wing incidence, stab incidence, etc.?

T.

Post by **GAHorn** » Wed May 23, 2007 7:21 pm

Since you're a member, I'll send you a copy of the file on rigging.

dacker · Post by **dacker** » Wed May 23, 2007 10:08 pm

I thought that the slight "nose down" elevator in cruise was normal.

Maybe that is why I only see about 115 indicated on my "A".
David

wingnut · Post by **wingnut** » Wed May 23, 2007 10:35 pm

I have noticed that while in level cruise flight, my elevators are deflected nose down - significantly.
Enough that the "leading edge" (the outboard portion at the front) of the elevator is probably 3/4-1" up.

Which is it? If the outboard portion of the elevator (the horn; not George) is up, then that would be elevator nose up,
instead of elevator nose down.

George,
I would also like the file for rigging, since I'm a member now. I've rigged a few and have acheived excellent results, however, I feel I've been re-enventing the wheel.

wingnut · Post by **wingnut** » Wed May 23, 2007 10:37 pm

Somebody wanna clue me in on how to qoute somethin without the whole thang bein that way?

3958v · Post by **3958v** » Wed May 23, 2007 11:00 pm

Your airplane is fine. That is the way Cessna made them. They were made that way so you can still get the tail down for a three point landing with the CG at the foward limits. The 170 has a very large range for the CG envelope. If you notice the 170 has more rear seat leg room than most other four place aircraft. Quote from "Cessna Wings for the World" by William D Thompson "We looked forward to expanding the C.G. envelope to make this an honest "4-place and baggage" airplane. Testing at forward C.G. with power off and flaps down showed inadequate elavator power for a 3 point landing. To correct this the angle of negative incidence for the stabalizer had to be changed to -4 degrees. This of course had to be counteracted in cruising flight with down elavator, creating some drag." Bill was a test pilot for Cessna. By the way its a great book for any one interested in old Cessnas. Bill K

tshort · Post by **tshort** » Wed May 23, 2007 11:33 pm

Thanks for the input.
I actually got my hands on a copy of the book, but have only had time to look at the pictures and read the captions ... sounds like an interesting read!

Thomas

mrpibb · Post by **mrpibb** » Thu May 24, 2007 12:55 am

Uber cruise, note down elevator

doug8082a · Post by **doug8082a** » Thu May 24, 2007 12:23 pm

Hey Vic,

How about a few shots of your 170 for the calendar? I haen't received any pics of straight 170s yet...

Post by **GAHorn** » Thu May 24, 2007 2:15 pm

mrpibb wrote:Uber cruise, note down elevator

Please note that, even with the drag of the elevator rigging...that Cessna is STILL AHEAD OF THAT PIPER!

wingnut wrote:Somebody wanna clue me in on how to qoute somethin without the whole thang bein that way?

Del...before the pic of the Pokey-Piper was posted (pic pokey piper posted ....there has to be a rhyme around here somewhere's...

....)
.... you could have shortened the appearance of your post by editing the quote...in other words, by adding a <enter-return> within the long sentence...as I DID within your post as an illustration.
Of course the Panoramic Pokey Piper picture posted, prevented proper portrayal of that.

The rigging file is on it's way to your email inbox.

Any Member wanting this file should PM or email me. Any non-member may learn how to obtain it by contacting me as well.

mrpibb · Post by **mrpibb** » Thu May 24, 2007 2:24 pm

Yeah but the piper was trimmed for slow flight. As for the calender might have to wait for the paint, and wings to come back.