Big Tail and Floats

[Nathan K. Hammond]

When installing floats on a big tail, do you have to install the aux fins i.e. tombstones or belly fin?

nkh

[rkittine]

If you are putting the floats on via the Type Certificate, the Small Dorsal Fins on the elevator are required. If you are using an STC then it depends on the STC. Bruce Dunhams STC requires them. The reason for the large tail is usually in which way a larger engine was installed - Service Letter or STC. The smnal fins are supposed to come off when the plane is not on floats, but I left the ones on my Chief on for 6 off seasons without any known adverse performance.

Like Bill Pancake, J.J. Frey, the past General Manager at EDO for 45 years, is always willing to take a phone call or an E-mail. Let me know if you need his contact information.

A good place for additional information is http://www.SeaplaneForum.com There are a number of guys there in addition to me, that have Aeronca, Pre-War, Post War and Sedans, on floats.

Bob

[Nathan K. Hammond]

Thanks Bob, I'll mosey over and ask around.

nkh

[rkittine]

NKH,

I think that you will find that part of this is what is legal or was called for, rather then what might or might not actually be a necessity. You will hear from Glenn (cubdriver2 on the SeaplaneForum site), that he never used the fins on his 7CCM Champ (Which I now own) The fin attachment bolts have been on either side of the elevator since I have owned it though. In a strong wind, the added longitudinal stability under way, is comforting.

Bob