How to flatten a battery on a c172
 

Hi, Long time listner, fist time caller,

I am having an arguement at work. I believe that on a C172 the flap motor will draw less current than the beacon and all avionics on.

If the flap motor was the only thing running, it would flatten the battery slower than if the beacon and all avionics were on.

The avionics that are on are: GPS, 2 x VHF, and transponder.

My arguement is that if all those things are on plus the beacon, the battery would drain quicker than if it had to power the flap motor.

Look forward to the replies. :)

For one check the Circuit breaker for each item, i'm pretty sure the flap motor when running would draw more current that the beacon and standard avionics ( i.e a transpnder and vhf ).

How do you propose to keep the flap motor running ?, when the flap reaches the selected position, it will stop ( microswitches ), therefore no current flow.

So someone is pulling your leg.

Could you go down to Repco and get me a long wait, cheers champ:}.

And a box of short circuits... :ok:

Get me some Round Tuits and half a kilo of mag drops cheers

Prop wash has also run out, more please.

Actually the flap motors are somewhat notorious (in earlier models) for continuing to hum away and either burn out, or give you 40 degrees when you least expect it!!! Some have no cutout at all, so you can leave it whirring away, so if you are the instructor, it is an excuse to nudge the student about situational awareness.......

Also a reason why lowering (electrically powered) wing flaps in a turn can be dangerous, but then I assume everyone already knows why?

If your a/c has pop type c/b's look at the amp rating for each circuit - that should give you a clue as to what draws more juice! The really old fuses from really old cessnas might not give you as much info about its' electrical system.

Oh, and the POH/operators/information manual might also reveal the electrical system in detail........and you might be surprised what draws a lot and what doesn't (or not of course).

Hope you win the bet?

Hmmm...

I believe Repco also sell Left Handed Screwdrivers...

TT

while your there can you get me a nine inch populating tool?

Such faith. These have never failed?

1723KG. I see where you're coming from with your original question. As Mr Proach says the cb's will tell you the draw for each item. Just add them up and there's your answer.:ok:

Fly it over SYD during APEC & the RAAF will do the rest!:ok:

Fly it over SYD during APEC & the RAAF will do the rest!:ok:

I just fell off my chair! What a classic comment!! :}

Buster...you are one funny bas:mad:tard!

OK time for a CORRECTION

Circuit breakers are not an indication at all of the current draw. yes it can be said on a big load you will have a bigger breaker however the circuit breaker is NOT there to protect equipment, it is there to protect the wiring. Otherwise the wires become the fuses:eek: and we all know where that ends up:{.

So think about it a bit closer, depending upon the actual load, the cable run, the environment of the cable, there will be a wire/cable size selected, then a CB is selected to protect the cable. There could be 5 x 3 amp devices powred by a cable with say 30amp rating, and a 20amp breaker.

Its a common misconception, so I am glad for once I can contribute something useful on here!

J

PS some strobes and electric DG's T&B etc draw some serious current! So you never know....the instantaneous current could be higher.....but if the motor runs on and on it will burn out possibly, and flatten the battery! So is it instantaneous current you are arguing over???

Go get a DC tong tester and measure it! its not hard is you have the tools! More trivia for you, the heating element demister in the windscreen of my race car draws about 7.1 amps @ 12vdc......that is more than I expected! Must get warm hey!

Must tell that to Mr Boeing and Mrs Airbus...

Cessnas don't have flap asymmetry switches.

try looking at the ELA (electrical load analysis) which is supposed to be kept in the front of the aircraft log book

Okay, I meant for drivers of lighties there Centaurus.............

And yes, the c/b's would only be an indication of loads.........

And just how easy would it be to shoot down a C172? :E

Wake turbulence???

MR. PROACH

While I haven’t flown a lighty for a while, I did fly a lot for many years and I don’t recall any of them having any requirements, restrictions or recommendations in their POH about the extension or retraction of flaps in a turn. This is one of those little wives tales that has been handed down from generation to generation of flying instructors and GA pilot as fact. Fact is it’s BS. Flaps are rated for all regimes of flight specified in the POH, period.

Let Kiwi Chick fly and it will fall out of the sky itself. :E

(what's wake turbulence? the ****e i fly through every time I turn through 360?" :ok: :ok:

Doesn't wake turbulence tend to move downward with time? You must be descending in your 360° turns....:p;):E

MR PROACH

Shooting down a 172 from an F/A-18 might be a nigh on impossible trick, but I reckon a Blackhawk chopper with a door gunner might have a good shot at it (so to speak).

Especially if you don't care where the bullets that miss the target end up...