I had bladders on my 182 and now have them on my Bonanza. Obviously the
best is to leave them full. I never had full tanks unless I was going a
long way, just wasn't going to put up with the decrease in performance
lugging around all that weight. What really hurts the bladders is to be
left outside in the baking sun, second is the temp change associated
with being outside. If there is any condensation as night falls now you
have water on the top of the bladder. This doesn't help bladder life.
The next best thing to keeping them full is an insulated hangar so
there's no sun damage and the change in temp is slow. New bladders now
a days last about 30 years, not keeping them full using the above
methods will reduce that to 25, so go for it. I didn't coat the
bladders with anything.



Mike Rapoport wrote:

I have a Helio Courier with four fuel cells holding 30 gallons each. My
typical flight uses ~35 gallons so I would like to leave the outer (aux)
tanks empty most of the time. I understand that leaving them empty will
reduce their life expectancy. How much should I expect the life expectancy
to be reduced? It there a proceedure to coat the inside of the bladders
with something that would preserve them? Thanks!

Mike
MU-2