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How many gallons to taxi, runup, and takeoff?


salty

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How long does it take you in minutes from start up to lift off?  I see people take 30 mins to do their thing and others are started and airborne in nuclear alert time frames.  

As a general rule of thumb though probably not enough to matter, figure 3gph unleaned.  

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My IO550 burns two gallons per hour while leaned on the ground... Measured with a FF gauge...

Full throttle departure is a 28 GPH affair... but only lasts a minute...

Start= 4gph

Leaned on ground, 1000 rpm = 2gph

run-up = 1700rpm for a minute

Your POH will have some numbers similar to this where they will say plan for 2 gallons or so....

O360 numbers will be similar while being leaned on the ground, and 20 gph at full throttle?(Guessing)

Having a FF gauge is a great device to have.

Best regards,

-a-

Edited by carusoam
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If you are leaning from start up and only idle and taxi at about 900 to 1000 rpm you will likely only burn 1 to 2 gallons on the ground.  

With the io-360 I burn about 18 gph on take-off, but lean continuously on climb so I find I burn about 11 gph average for the first hour on a normal climb out to 4 to 5 K agl and then leaned to 9 gph.

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Short Answer:  If the engine is cold and I am going to have to wait for the oil to come up to 90F before I do my magneto check, I plan on 1 gallon for STTO (start, taxi, takeoff).  If the engine was warm, I plan on 0.5 gallons.  And I think that is pretty conservative.

Long Answer:  Leaned on the ground I burn about 2 GPH.  If it takes me 9 minutes to warm the engine and taxi, that is .3 gallons.  I do not do a full rich magneto check and I don't spend a lot of time (probably 30 seconds with the engine run up) so something like .5 minutes at 6 GPH.  That's 0.05 gallon.  I'm up to .35 total so far.  If you watch a video of a Mooney takeoff, the ground roll is usually less than 15 seconds.  Let's say it takes 30 seconds to get airborne, gear up, flaps up, and up to climb speed.  That's 0.5 minutes at 18 GPH.  That is 0.15 gallons.  Total is now 0.5 gallons.  I would have to spend an extra 15 minutes on the ground at 2 GPH to burn that extra half gallon.

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I'm in Florida so warm-up time is pretty short. I wait until 100deg for runup and seem to consistently take 7 minutes from turning on the avionics master until the start of the flight (subtracting flight time from start-up time in the "Flight Timers" section on the GNS530). According to my fuel totalizer, I burn less than 2 gallons when lean on the ground, but I go full-rich for run-up. 

I compute things a bit differently and developed this habit prior to getting my fancy engine monitor. My F carries 32 gallons of usable per side. When run dry, I can get between 33-34 gallons in the tank. I try to get 3 hours on the tank that I started on first. Whether it means I switch tanks after an hour and a half or just run it for three hours and switch, but I know if I make 3 hours on the side I warmed up and climbed out on that I have that much safely remaining on the other side. I don't include time on the ground in flight time; you burn more on the climbout; and I was surprised to see as high as 17GPH on takeoff and initial climb when I got the fuel computer. 

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Warm-up times have been cussed and discussed on this forum in the past.

My POH defines "warm enough" as being able to push the throttle forward to takeoff power without the engine stumbling.  There is no minimum oil (or CHT) temperature for takeoff listed in the limitations, or text.

I live in a warm climate, so I'm probably a little lackadaisical about warm up, but I'm interested in where the various minimum oil temps for takeoff come from.

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1 hour ago, Antares said:

I'm guessing "airspeed alive, instruments in the green" from our primary training has something to do with it. 

But that's already on the takeoff roll. Why do people sit on the raml, burning gas, before they start moving? Even in West-by-God, Uncontrolled Virginia, I could cold start and be leveled off at 7500, power set, leaned and chatting with my wife in less than 15 minutes.

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