Cessna 337 Skymaster
|Type||External tip tank|
|Added fuel total||39 gallons (19.5 per tank/side)|
|Useable fuel total||38.6 gallons (19.3 per tank/side)|
|Net added span||52 inches|
|Gross weight increase||Total of 4,630 (if gross weight is 4,700, it will stay the same)|
|Dry weight||46.3 lbs|
|Installation time||45-60 hours (with previous installation experience)
For aircraft subject to AD2011-15-11 add 20-30 hours.
|Need to be painted||Yes|
|STC and models covered||
|Flight manual supplement|
|Limits||At weights between 4330 lbs. and 4630 lbs. there must be at least 12 US gallons of fuel in each wing tip tank.|
For aircraft subject to AD 2011-15-11 add $2,100.00
We’ve been selling extended tip tanks for the Skymaster since 1989. They carry 39 gallons total, 38.6 usable. They are fiberglass tanks that bolt onto the end of the wing and replace the factory tip. New holes are drilled in the wing skin and our tank/tip is bolted in place. The overall span is increased by 54 inches which results in a better climb and above 10,000 feet, we usually get reports of an additional 3 or 4 kts in cruise speed. The tank has it’s own filler cap and quick drain valve. We ship the tanks in gray primer so they must be painted to match the wing.
For tank installation the close-out rib is removed and if you have strobes, the transformer is re-located to the inboard side of the rib.
The next step is to run the fuel line inboard to the part of the wing where the strut attaches. The transfer pump is mounted here along with two check valves. The fuel line is then run inboard to the main tank. For rubber cell mains, the fuel enters through a tee fitting in the door post into the fuel line that runs from the mains down to the engine. For metal main tanks, a bulk head fitting is installed in the side or top of the main tank.
Gauge(s) and lighted rocker switches are then mounted on the panel, pedestal or over the doors. Apply the placards, fill out the 337 and you’re finished.
The kit is quite complete including tanks, caps, mounting and plumbing hardware, transfer pumps, check valves, fuel line, wire, switches, gauges, fuses, installation drawings and STC. You supply some PRC sealant if your main tanks are metal.
Local installers complete the job in 45 hours but if you have someone do it that has never done one before, it will probably take 60 hours. It’s not an exotic installation but, done right, it takes some time.