C-130A Fuel System

[Wombat]

A models without -II mods could hold: outboards= 8,400 lbs by SPR, inboards= 7,600 lbs by SPR. The A does not have a 3% airspace filler neck as for B and on, so can be overwing filled to overflowing. Full SPR is 32,000lbs. Full over the wing is 34,000lbs. The pylons are ex-C123 units of 450 US gals for a total of 3,000lbs each. Max fuel is 40,000lbs.

The wing is plumbed for active "1,200 gal combat external" tanks that were self sealing in the lower half, but were only installed on -II when needed. The "toy" tanks feed into the inboard tanks via the dual float control valve.

The feed logic for the feed method for the -II tanks was to use the internal fuel before you enter a combat zone, select the externals via the square switches on the fuel control panel, hit the Wing Tank Purge button then fly on external fuel only. The purge air pressure was vented via the vent valves. The combat logic was that the wing is a very large target where as the pylons present a smaller target to aim at. The tank purge system was removed and the purge hole sealed. The purge system and external tank info is available in the older manuals for " reference only".

As with other systems, the A model went through a lot of changes during production due to some systems being outdated by the time the B was introduced. It is a technically "dirty" aircraft.

Edited January 23, 2009 by Wombat
Addition of further reference info

[tristar]

The "A" model was originally designed to have 4 large pylon tanks like the E model but the stress on the wing was so great and the weight was enough to put the acft overweight.

the tanks were never put on but a look at the fuel panel will tell the tale.

There are switches for external tank to engine but no tank. Switching the valve to Ext tank to eng will cause a promp flameout of the engine..found that out in Buenos Aires..wanted to spend the nite..and did.

The two 325 Gal pylon tanks were an add on that just bearly gave you an hour of extra flying time and no tactical landing work could be done if there was any fuel in the tanks.

The A model fuel panel is one confusing panel until you work with it a while. If you ignore the external tank to engine switches and just use the crossfeeds , you will be ok and someone thought that the acft had not bladders in the tanks and they were right. Only the gunship versions had the bladders or foam in the tanks.

[ang012]

In the 80s we took one of our planes out to a res. base just south of kansas city to have some fuel work done.They had a A model there that had a aux tank fuel bladder in. They were pulling it out to do work on it and the paratroop door windows were the square ones. It had a regular camo paint job and with the ramp open it looked like a regular cargo plane.

[bischoffm]

I don't remember the gunships having any bladder tanks, but they did have foam and extenals. Hose clamps to hook them to the aicraft with no fuel indication. The only way you knew they had fuel after you hung them was during the leak and transfer checks!! they did not add much distance, but did give the crew enough fuel to do several touch and goes after we got to the DM, what fun!!!

[steve haigler]

The C-130A model had pylons, rule of thumb on preflt. for proper distribution was 617( why 617? because that was the capacty) more in outbds. than inbd. On in flt. use the main tank cap. had to be below I believe 5800# before the flow could start. If flow could not be established activate the leading edge de-ice for possible ice in fuel line from the pylon.

The 3 pylon switches were above the engrs. head. 2 for pump on and 1 for flow.

Steve

[JayTee46]

C-130A Pylon wing tanks outboard of #1 and #4 Engines fuel capacity was 450 gallons each, each tank had a filling cap which you removed and filled by nozzle hose.