Leading Edge Fuel Tanks

By Bob Stephens

As you will probably be aware from articles in recent editions of this newsletter, I have been considering the problems of C of G in the Zodiac, in particular the HD version. After much discussion with Alan Cozens and Ernest Brown I decided that the installation of leading edge tanks might go part way to solving the problem. My reasoning behind this is that any weight on the rear parcel shelf has a great effect on the C of G. Therefore placing this weight nearer the C of G should hopefully minimise this problem. The only problem here is generally the wing lockers are use for fuel rather than baggage. This is when I remembered seeing a note in Zenair News about the use of leading edge tanks (it so happened at this time I had had a long discussion about this with Alan Cozens). Anyway I dusted off the said copy of Zenair News and wrote to Chris Heinz requesting further details. A couple of weeks later (and $25 poorer) I receive what can best be described as the back of a fag packet design on two sheets oA4. So it was going to have to be an original design with all the associated problems of approval.

The main factors I felt I had to consider were:

Ability to remove the tanks for inspection/maintenance.Ease of installation.Ability to fill the tanks through the leading edge, but without disturbing airflow in this area significantly.

The sketches re-produced below show an outline of what I plan to send to the PFA for approval and hopefully give an indication of what I intend (the actual sketches for the PFA run to 8 pages of A4).

Sketch of the proposed leading edge wing tank

Sketch of the section of wing where the leading edge wing tank will be located (inboard end of outer wing section)

Sketch showing how leading edge tank fits in between the two inboard ribs