Question on 15 gal tip tanks for the Piper Comanche single

[Jerry Fitzgerald]

Looking at installing OSBORNE, formerly Brittain Industries tip tanks and found that the STC is only for 15 gals per tip yet the Beech and Navion gets 20 gals per tip. Anyone know what reason for the smaller tanks?

I am guessing the wing span may be longer therefore the extract 5 gals may have caused some structural concerns with the FAA.

A friend thinks they only tested 15 gal tanks but why would Brittain do that?

Decades ago but hope someone can answer the question.

[William Hughes]

Can't answer your question, but I recently installed these on my 1960 PA-250. I am probably backward rationalizing the decision but it is really nice to have that extra fuel.

[N3322G]

Jerry,

The previous owner of 3322G, my Hall of Fame Mom, Marion Jayne pursued trying to get the 20 gallons approved for Comanches but testing, etc was cost benefit prohibitive so she got the 15 gallon tip tanks, 19.4 gallon wet wings and 10.2 gallon nacelle tanks added to the existing 30 gallon mains and 15 gallon aux tanks for the 1992 world race. With FAA approval for 90 days to be 30% over gross, a 72 gallon ferry tank was added on the spar for the 1994 world race.

I still fly 22G and have seen nothing out of the ordinary for the Twin.

FYI. I've seen 'Dolly Parton' 100 gallon tip tanks on two different Beech A36s.

Hope this answers your question and provides a bit more about extra fuel tanks. IMHO extra fuel is the best speed mod.

[Matt Bogard]

I'm very happy with my tip tanks. The extra 200lb gross weight increase is great, as is the extra range. I love that I can ferry fuel to places like Chicago and Oshkosh where it's more expensive rather than filling up to get home.

[Jerry Fitzgerald]

Thanks!

I fly to the Caribbean and could use the extra 5 gals/tip but guess I will be happy with the additional 15gals/tip.