The International Cessna^® 170 Association

Will the tails on the A and B models --vert, horizontal, elev, rudder -- interchange ?

Rudder and vertical stabilizer to the best of my knowledge are the same between models.

The elevators and horizontal stabilizers are completely different. Next time you have an A and B next next to each other examine them carefully. The first thing you will notice is the trim tab is completely different. Then you may notice the shape of the counter balance area and the trailing edge of the elevator on the B model is flatter than the A model. The stabilizer itself looks the same and probably has some common parts between models inside but the hinges and their locations are different and not interchangeable between models. Additionally the A model elevator is not a balanced surface and the B model is.

Now I happen to know that the entire horizontal stabilizer and elevator as a unit is interchangeable between models as far as fit and function goes. Legality is another issue.

Don't feel bad not knowing all this. 8 out of 10 170 owners, even long time owners I talk to don't know this and never noticed.

N9149A wrote:...The elevators and horizontal stabilizers are completely different. ...
Now I happen to know that the entire horizontal stabilizer and elevator as a unit is interchangeable between models as far as fit and function goes. Legality is another issue. ... .

While the A-model horizontal stab. and elevators might be fitted to a B-model fuselage... they do not have identical characteristics. The reason the B-model has a different elevator (yet the same vertical and rudder) is because the major change from the A-model was the much larger flaps on the B. When those larger flaps are fully deployed they create a much larger down-wash and significantly alter the angle-of-attack of the horizontal and elevator. The B-model's elevator is more effective than the A-model in order to accomodate that.

(If one were to locate such an airplane...i.e., one which appeared a B-model with an A-model's horizontal and elevators.... I imagine it most likely is an A-model with B-model wings, instead of a B-model with A-model tail... regardless of what the dataplate may indicate.)

Of course George is right in his detailed explanation of the differences and why they where made. I know of at least one A model not including mine with a B model elevator and have heard of a few others but not seen them.

I wouldn't consider and wasn't thinking in terms of putting an A model elevator on a B model but rather the B on an A. To be honest I'd not consider any swap unless there was just no A model elevators available for the A model and no repairs where possible. Having flown both elevators on their respective models the difference is not enough to warrant the work.

Thanks. I had the same question, because I was about to buy a B model elevator that would not fit my A model stabilizer.
Donovan