Main gear toe in

[Bruce Fenstermacher]

Wanted to confirm what people are using or have successfully used for toe in when aligning a 170.

The 100 series service manual does not specify anything for a 170.

It specifies .06" for milk stool models 150, 172, 175 and 182. Milk stool models can probably have closer tolerance as they are steered by the nose wheel and not as critical.

The service manual specifies .012" for the 180 and 185. Chamber for the 180 is .18". I did a search here and there are some excellent posts and one of them mentions .012" but it is hard to tell if that post is specifically for a 170 as it was a copy of instructions from elsewhere and it doesn't specify specifically .12" for a 170. Anyone know where specific info for a 170 is found?

Probably won/t go wrong using the 180 info but I like to use the best/correct numbers.

Thanks

[n2582d]

SLN-56 says the desired toe-in is zero. The tolerance is 0" Toe-Out to 1/16” (.0625") Toe-In for each wheel. The C-180/185 toe-in of 0"-0.12" is total toe-in. Here's a screen shot from the 100 Series '62-'68 Service Manual.

So it matches the C-170 specs above as those are for the individual wheel.
Another data point is the L-19 which is 0"-1/16" for each wheel. This too matches the C-170 specs. but differs in that it calls for the plane to be "loaded to a normal load condition". Here's what the 100 Series Manual says regarding aircraft weight:

Fig. 5-9 C-100 Series '62 and Prior Service Manual
Click to Enlarge

[mschlender]

No toe in

[gfeher]

Gary, would you post a copy of the actual/original SLN-56 in the MX Library? The link to SLN-56 you posted only has re-typed text from the SLN. It would be nice to have a copy of the original SLN in the library.

[Jim Collins]

When I had my first annual at "Blue Skies" in northern Illinois, they raised the tail to level the plane, added weight inside the cabin, measured the tow-in and camber and calculated the shape of a shim to set the tow-in and camber to zero and had a set made using CNC. Now the plane lands very easily. Where as before, landing was a real handful (there was a lot of tow-out).

Jim Collins
N2488D 170B

[Bruce Fenstermacher]

Thanks Gary, it's hard to remember where all the information is located that we have. Even for me.

Also thanks for pointing out that .12" is total toe in for a 180 not for each wheel. I'd missed that point.

It is also nice to know the 170 instructions call for the alignment being done at empty weight which is a lot easier to accomplish that loaded.

After 71 years with cross-wind gear installed, we are removing them from N7A.

Dry fitting the axle with the -23A bolts called for, the -23s are to long. A -21 might be perfect maybe a -22. Also noted that the A model IPC shows the axle bolts with the head toward inside of the gear leg and the B model IPC shows them opposite.

[n2582d]

Bruce,
Glad to help. I know what you mean -- there's a lot of material to search through to find what one is looking for. Sorry to hear you're abandoning the X-wind gear. Those are Uber cool as my kids would say. You’re probably the world’s last holdout - if not for the crosswind gear then for the Goodyear brakes. I see you have the sale pending on your plane. A sad congratulations if that makes sense. Understandable that the new owner might be uncomfortable landing sideways.

When I had my first annual at "Blue Skies" in northern Illinois, they raised the tail to level the plane ... .

Jim, It's interesting that they raised the tail when aligning the wheels. I've always done it in the three point attitude. I couldn't find where it specified one way or another in the '62 and Prior 100 Series, '62-'68 100 Series, and C-185 Service Manual. The L-19 Service Manual however does say, "Check toe-in with the aircraft in a three-point attitude ... ." The engineers here could figure out exactly how much difference one would see in the toe-in alignment between three-point and tail raised. My guess is very little difference.
Gene,
I edited my earlier entry to link a screenshot of the original SLN-56.

[170C]

It was interesting to me the comment Jim made regarding toe out on his plane. Years ago I recall reading that toe in could cause landing our planes become squirrley . Maybe I misread it and it was toe out that could cause that condition.
I have noticed my right main tire wearing quite a bit on the inside while the left hand one hasn't done so. I've reversed the tire on the wheel and will be using the above data to ck my alignment.

[Bruce Fenstermacher]

You’re probably the world’s last holdout - if not for the crosswind gear then for the Goodyear brakes.

Gary, it is a double sad day. Removal of the gear and having to sell the plane in the first place. I know how rare the cross wind gear is. These where installed on N7A in 1949 must before the registration was changed to N7A. Leroy and I might have been able to keep them in service for a few more years but our stock of usable brake cylinders, the Achilles Heal of the system, is down to one and they are side dependent. It makes little sense the new owner would want them and I expected they would come off. Just didn't think I'd be doing it.

In the 12 or so years I've operated the Goodyear crosswind gear and brakes, I've only thought I was going to wipe out runway lights once. That was at a convention fly-out with Jim Wildharber as a passenger. You see you MUST land cross wind gear on the up hill or up wind side (half) of the runway cause the tail is going to swing down hill or down wind. I got caught not picking up on the fact the grass runway we were landing on had a pretty good slant to it after passing the crossing runway. I managed to swerve in and out of the lights coming to rest between them. Jim was impressed. As for the Goodyear brakes, believe it or not I have never had any trouble with them. I don't know if it is because while very similar to the regular Goodyear brakes, they are slightly different. Parts are not interchangeable.

[c170b53]

Frank “Normal” wear I believe usually occurs on the outside ribs of the tire which normally contact the ground first. If you look at the gear in flight they hang in accentuating the camber, so it would be interesting in what you find on that wheel with the wear on the inside. I just rotated my tires this annual on the rims to even out the wear. As for toe-in, there’s a few differing views out there. Ideally I think you want zero toe-in.
I believe some like a small toe-in for directional stability. Some believe, too much and the wheel will want to drive in which maybe undesirable should the gear leg be folding in during a crosswind landing. For that reason, some like a small toe-out, believing it wii assist to drive the opposite high wing down during a crosswind landing.

[GAHorn]

I’m fairly surprised you guys have forgotten this detail, but the Owner’s Manual gives this information under the “Care” section. All three models wheel alignment is specified to have Zero toe-in and Zero Camber at 2,000 lbs in the THREE POINT ATTITUDE.
If you don’t have an Owner’s Manual available, you may download one on the “Member’s Page” of this webstie.

[n2582d]

George,
We all realize that was there. But Bruce was looking for approved data so I referenced a Service News Letter. As a certain moderator frequently points out:

... As a reminder to all: OWNERS MANUALS are NOT approved documents. They were produced by the marketing department. ...

[GAHorn]

SNLs from the period of time of our airplanes were not “approved” documents either.

[n2582d]

According to Cessna S.N.L. 3-31-58 their Service News Letters carry "full CAA approval".

Service News Letter 3-31-58 pg. 1 Click to Enlarge

Service News Letter 3-31-58 pg. 2 Click to Enlarge

[GAHorn]

Gary, that was done retroactively I believe. Note those particular ones were issued in 1958. I have (and gave away entire copies of the early ones at Kelowna convention) the early SNLs that were not approved by anyone but Cessna publications dept. In fact, the second SNL you posted implies that “all service information” previously published was “approved” which might include the Owner’s Manual service information. Certainly the information is the SAME info... therefore it could be said to be “approved”.

My old post regarding the Owner’s Manual not being an approved document is still valid under either assumption.

Edit: Another example is the performance data in the Owner’s Manual. Although it is incorporated into that unapproved manual... the data itself is IDENTICAL to that “CAA Approved” in the AFM. While the entire OM is not approved, it contains approved data.