(Mark) wrote in message om...
Can anybody tell me what a realistic cruising range is for a Seneca
III with long range tanks a a full load (i.e. six people including
pilot)?

Not sure about the III, but my Seneca II POH is as follows:

Assumptions. Max T/O weight. No wind. Max rate climb. 1000fpm
descent. 4.2gal fuel at start, t/o, taxi. 10000ft. standard temps.
45 minute reserve

93 gallons (normal tanks): 550-630nm depending on power setting (75%
to 45%)
123 gallons (long range tanks): 770-880nm (75% to 45%)

Range increases about 5% by flying at 20000ft.

Payload for a Seneca II is about 1700lbs. Which leaves 1140 or 960
lbs depending on short/long range tanks options. Not enough to load
(6) 200lb'ers but better than most.

-Nathan