herkyjerky

First, each flight deck fuel quantity indicator sends a one wire resistive signal to a relay. This signal is called the rebalance signal, I think. This relay is controlled by the SPR master switch. When the SPR master is off, the rebalance signal for each gauge goes to a summation unit. The summation unit, located in the left hand hog troth, has a pot for each tank signal that is adjusted during the totalizer calibration. Each of the pot output signals are added together. The output from the summation unit goes to the total fuel indicator. When you turn the SPR master switch to any other position than off the relay energizes and sends the rebalance signal to the SPR fuel gauges, so you can refuel the airplane and not have anyone in the flight deck. When the SPR gauges are working, the totalizer is inop and the "SPR ON" light on the fuel panel comes on. And that's it, I hope this sheds some light on the totalizer thing.

Thanks! Now I just have to figure out the equivilent readings from those POTS and I should be in buisness. (After they are calibrated)

Anyone have any idea what kind of signal feeds the fuel totalizer on legacy fuel quantity systems? (Not the BF-Goodrich digital type systems)

The individual tank gauges do the work reading the capacitence probes, but they send a single wire signal to the totalizer.

My first guess was DC linear voltage since that is popular for those types of applications, but I can't find anything on haystack or the TO/specs that says what it is.

Thanks in advance!

(Trying to debug and read the signal for an international customer I'm working with at the moment)

At 14 mil a pop AMP is double what Boeing said it would cost (7 Mil) Most H-Model modernizations cost anywhere from 3-8 million based on the complexity. The US (and other gov) are not dumb, they know what other cockpits cost and that 14 mil is kind of a rip off. (Which is why you don't see alot of people lining up to get this mod)

Nat. Guard programs especially do not like the risk/cost of going to AMP.

On top of all that, the J-Model is not fully CNS-ATM compliant, late, and completely owned by Lockheed. (So upgrades come in blocks and 100 mil price tags) Right now the users of the H-models are kind of stuck between a rock and a hard place as "other" options would involve deviating from the congress spending on AMP and J.

Oh what fun politics are :-D

Noticed a gauge and a guarded switch on the lower left of the center console. What's that for?

EDIT: Whoops! Need to look closer...

Sorry that was confusing for a second. That's one of the older models, that panel appears to be a radar control of some kind. This bird still had a boob tube monitor and joystick :-) I'll find a higher rez pic and see if I can find that sucker.

Don't know what that photo is doing in this thread, but thanks, it's a neat photo. Although the instrument panel has a lot of new toys for the pilots, the FE's panel looks exactly the same as it did the last time I was in a Herc cockpit -- December 1995 doing a ferry flight from Luanda to La Paz.

Don R.

That is a Canadian Herk :-) And those toys are older then i am haha.

As for the FE panel, it's hard to beat it's design, functionally it is one of the better laid out things I've ever seen in any aircraft. (Just my personal opinion.)

This bird has since retired, need to look at my other pics I forget which tail number this was.

:-)

EDIT: Found it!