Fuel consumption.

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buck82
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Re: Fuel consumption.

Post by buck82 » Thu Mar 29, 2012 7:01 am

Whooops! My bad Wang doodle, sorry about that. I am human after all. Have a good season yourself.
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flyinthebug
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Re: Fuel consumption.

Post by flyinthebug » Thu Mar 29, 2012 1:45 pm

Colonel Sanders wrote:All my numbers are in US gallons, which is what my fuel totalizers indicate.
x2 I was quoting my fuel burn @ 28 GPH as US gal not Imp. I agree with the 1.5 hours for front and centre each and 1 hour for rear. Thats a good rule of thumb.
PS.. I said I used 31/20 for cruise it was 31/19 not 31/20. Most of our trips were in climb phase anyways, so rarely used cruise settings (west coast in the rocks). Once you get above 5000' you can only get 31" MP anyways firewalled.
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letsfly
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Re: Fuel consumption.

Post by letsfly » Mon May 21, 2012 5:01 am

The numbers I use for piston engine is HP / 20 = fuel burn per hour.
Beaver 450/20= 22.5
206 300/20 = 15
185 same as 206
180 230/20 = 11.5

Not quite as simple with the turbine. Have not yet figured out an accurite formula, but over time, maybe!
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rigpiggy
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Re: Fuel consumption.

Post by rigpiggy » Mon May 21, 2012 6:22 am

Turbines being a different animal. A good correlation being the torque used. During the winter, when temps are cold you can hold rated torque to a higher altitude. Your torque/fuel flow/IAS will bee almost the same, as at a lower altitude, however your TAS will be higher at altitude. You will gain some efficiency due to the delta T difference, but FF will remain very similar.
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ZPC2THLgate
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Re: Fuel consumption.

Post by ZPC2THLgate » Fri Jun 21, 2013 11:51 pm

Leaning will only reduce the engine life. Good way to blow jugs.






























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Zopo ZOPO ZP950+ ZOPO ZP950
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Last edited by ZPC2THLgate on Mon Jul 01, 2013 12:25 am, edited 1 time in total.

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iflyforpie
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Re: Fuel consumption.

Post by iflyforpie » Sat Jun 22, 2013 6:06 pm

ZPC2THLgate wrote:Leaning will only reduce the engine life. Good way to blow jugs.
No.

You 'blow jugs' by operating the engine outside of its parameters. Too high CHT, too high MP, too low of fuel grade, or allowing the engine to detonate.

Shoving the mixture full rich will blow jugs faster than leaving the mixture too lean when reducing power.

Also, a mixture that is too rich will foul plugs and cause exhaust valves to stick.

'Babying' your engine will introduce other problems as well. Not pulling enough MP at high RPMs can unseat the piston rings, causing blow by and increasing oil consumption. Running your engine too cool will cause piston slap, because air cooled engines have very loose clearances unless they are at their proper operating temperature.
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geodoc
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Re: Fuel consumption.

Post by geodoc » Sat Jun 22, 2013 8:17 pm

Edit ......................

An engineer friend pointed out to me once that every spark ignition piston engine burns approx. 1/2 pound per H.P. / hr.

Try it, amazingly close.
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Last edited by geodoc on Sun Jun 23, 2013 2:13 pm, edited 1 time in total.

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geodoc
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Re: Fuel consumption.

Post by geodoc » Sat Jun 22, 2013 8:24 pm

Without a doubt, the best thing I have come across for the hows & whys of fuel / air mixture management for air-cooled piston aircraft engines:

http://www.avweb.com/news/pelican/182084-1.html

Read some of John Deakin's other stuff on "Pelican Perch" in AvWeb. Great stuff.
iflyforpie wrote:
ZPC2THLgate wrote:Leaning will only reduce the engine life. Good way to blow jugs.
No.

You 'blow jugs' by operating the engine outside of its parameters. Too high CHT, too high MP, too low of fuel grade, or allowing the engine to detonate.

Shoving the mixture full rich will blow jugs faster than leaving the mixture too lean when reducing power.

Also, a mixture that is too rich will foul plugs and cause exhaust valves to stick.

'Babying' your engine will introduce other problems as well. Not pulling enough MP at high RPMs can unseat the piston rings, causing blow by and increasing oil consumption. Running your engine too cool will cause piston slap, because air cooled engines have very loose clearances unless they are at their proper operating temperature.
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ruddersup?
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Re: Fuel consumption.

Post by ruddersup? » Sun Jun 23, 2013 1:47 pm

I think you want to say 1/2 gal per every 10 h.p.
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geodoc
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Re: Fuel consumption.

Post by geodoc » Sun Jun 23, 2013 2:12 pm

ruddersup? wrote:I think you want to say 1/2 gal per every 10 h.p.
oops .......................... it was getting late and skipped the proof read -

meant 1/2 a POUND per HP per hr.
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Starboardwing
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Re: Fuel consumption.

Post by Starboardwing » Thu Apr 21, 2016 2:05 pm

geodoc wrote:Without a doubt, the best thing I have come across for the hows & whys of fuel / air mixture management for air-cooled piston aircraft engines:

http://www.avweb.com/news/pelican/182084-1.html

Read some of John Deakin's other stuff on "Pelican Perch" in AvWeb. Great stuff.
iflyforpie wrote:
ZPC2THLgate wrote:Leaning will only reduce the engine life. Good way to blow jugs.
No.

You 'blow jugs' by operating the engine outside of its parameters. Too high CHT, too high MP, too low of fuel grade, or allowing the engine to detonate.

Shoving the mixture full rich will blow jugs faster than leaving the mixture too lean when reducing power.

Also, a mixture that is too rich will foul plugs and cause exhaust valves to stick.

'Babying' your engine will introduce other problems as well. Not pulling enough MP at high RPMs can unseat the piston rings, causing blow by and increasing oil consumption. Running your engine too cool will cause piston slap, because air cooled engines have very loose clearances unless they are at their proper operating temperature.


I have read through all of John Deakin's engine articles on AvWeb over and over and have become very curious as to how this material relates to radial engines. It seems that the history of running engines LOP actually started in the "heyday of the big radials" (as Deakin puts it) but neglects to mention the specifics about how the big old radials were actually handled. And how is the R-985 any different? I understand we don't have BMEP guages, and engine monitors in the beaver. But I have a sneaking suspicion that the fact that getting to TBO on a beaver is somewhat of an accomplishment means that something isn't right here. Shouldn't proper engine handling be rewarded by longer engine life?? is running LOP on a beaver feasible?

Pie mentions the possibility of running an engine too cool. Is this a concern in the beaver? I recall that I was always weary of CHTs hovering just over 400F, in some cases up to 420F. From what I read from Deakin, one of his remedies would be to leave MP at a higher value on TO, and to decrease RPMs. How does this technique translate to a supercharged radial engine?

Any intelligent thoughts would be greatly appreciated.
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oldncold
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Re: Fuel consumption.

Post by oldncold » Fri May 06, 2016 7:03 pm

dhc 2> time in tanks starting at the front fuel tank> 1hour +20 min // middle fuel tank> 1 hour+ 20 min// rear fuel tank >45min for sure, 1 hour if your technique is spot on . So to have sufficient legal vfr reserve ( day vfr 30 min) you have with all tanks filled 3 hours and 10 min of flying time. + 30 min reserve .

All that have more than a few hours in the ole beav know the back fuel tank is a water + condensation collector so don't get lax in the pre flight. The exp dhc-2 drivers I've ever met made a habit of keeping 5-7 gal in the back fuel tank, as the weather went shit have to sit down on a lake granny gas scenario.

206g models models long range 88 us gal usable block fuel burn at 20us gal /hr x 4 hours you will golden ( beside most of us have to take a pee break after 4hours anyway) less one hour and 15 min if the older model 66 gal useable

If your math isn't so good, a rule of thumb I've used over the years is , 4 gallons for every taxi n take off in a beaver and 3gal for a 206
Wish you safe and memorable season.

so a typical trip in a dhc 2 may look like this: Take 3 and gear plus some supplies for the camp to lake x 80 miles away, drop them off. Pop over to lake y 20 miles from lake x to do camp check. Then pop over to lake z 15 miles from that lake , pick up 4 guys and gear bring back to base. so they can be on the road by noon.

fuel required 4 taxi n take offs (16gal) and approx 195 miles of flying giver or take 20 miles if the outpost lakes are closer or farther on the return back to main base so 2hours 15 min if your beaver is average = 46 gal plus 16gal = 62 gal splash of grany in the rear and good to go
weight n balance on floats dhc-2 typical 1450 -1550 useful load = the 67 gal of gas =402lbs and 3 large fisherman @250lbs 1152 add you @180lbs cuz your in top shape =1332lbs leave ya enough to take some 3 flats of beer and grocery unless your beaver has the up gross to 5400 lbs mtow
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