Fuel Burn

[I Я Instructor]

... is there any database on the Internets with piston aircraft average fuel burn? Say you want to know what a 172 or 182 burns per hour or small twins etc.

TIA

[767]

ooops, nvm.... misunderstood your post.... nope i dont know any sites.. sorry

[Invertago]

For guesstimating fuel burn on aircraft you can figure about 5-6 gal / hour per 100hp in cruise configuration. Use this information when surfing the internets to satisify curiosity and looking at airplanes... please don't use it for flight planning purposes

Oh, and it is for avgas lyco / continental engines, turbines and diesel engines are way different.

[mathewc]

Just download the POH from different manufacturers (i.e. Cessna, Piper, Diamond...) and compare.

[Hedley]

Since pilots haven't a clue what BSFC is ...

Here's the easy way to do it. On takeoff, with
a 300hp engine, you'd better be seeing 30 gph
fuel flow on your totalizer, at full rich mixture,
or you're gonna fry your exhaust valves.

Running it at 66% power for cruise is 2/3 of 30 gph
which is 20 gph at 200hp. You'll do a bit better
than that (esp if you're fuel-injected) and leaned
out correctly.

Let's look at a 172 with 150hp. Knock off a zero,
you're going to be 15 gph in climb, at 10 gph in
66% cruise. Maybe slightly better than that, if
you bother to lean it - most people don't - or if
you use a lower power setting for cruise.

Remember: the hp the engine is producing,
knock off a zero, and that's your gph at rich mixture

I am truly amazed that barely any pilots are aware
of this basic fact of internal combustion four-stroke
engines. It takes gasoline to make power.

[Time 2 Vent]

Check out www.planequest.com (go to the operating costs page)... This website has many different aircraft and composes statistics for operating costs such as fuel burn, insurance, hangarage etc. All the numbers are submitted by owners / operators some of them will change based on your current situation / location for the most part the numbers are in the ball park(again type dependant and who is operating them.. private or commercial).

[Invertago]

Since pilots haven't a clue what BSFC is ...

Base specific fuel consumption is not something covered in most ground schools, I know about it because I'm always trying to put together my perfect dream home built aircraft that when I can afford it I'll build. So... I'm always trying to compare ideal engines out there so when I do buy a kit, I'll have a clue about what I'll power it with.

Small diesels are around the 0.35-0.45 lbs/hp/hr, on a good day your lyco will get around 0.45lbs/hp/hr. Small turbines typically pull in around 0.6 lbs/hp/hr.

BSPF is more of a lets compare engines and not something really important as far as basic flight training, and you'll never see it on a TC written exam as those are just about memorizing random trivia.

Anyhow Cranky Pants aka Hedley probably just woke up on the wrong side of the bed so don't mind him. BSFC is basically a useful tool for comparing engine efficiency. Best take your fuel burn #s from the POH.

[Hedley]

Base specific fuel consumption is not something covered in most ground schools

It oughta be covered in Commercial - certainly ATPL - groundschool.

Sure a PPL might not have a clue what a four-stroke engine is,
or how a carburetor or magneto works

But a CPL/ATPL sure as heck ought to!

P.S. It's actually:

http://en.wikipedia.org/wiki/Brake_spec ... onsumption

I actually think you should know about things that can
kill you, but I'm perhaps a tad old-fashioned that way.
Perhaps I can start wearing gel in my hair?

signed, Cranky Pants

[Invertago]

Brake, my bad, I had brake on my mind but the fingers decided to type base. 10 fingers/thumbs, only one mind to keep track of them, so schieet happens. As for things that can kill you, I plan on continuing my learning for the rest of my life, but being that I can't learn it all, there are much more important things to save my life then BSFC. 20min of exercise daily will likely do more prolong my life more then a solid knowledge of BSFC. In terms of flying, I'd say a good course on weather would benefit pilots a lot more then studying engine efficiency. I also think that running out of fuel enroute is more an issue of decision making, planning and too high risk tolerance then it is of a lack of BSFC knowledge. Know the engine you are flying, knowing a/c and engines that you don't fly is just gravy really.

PS. Gel wont fix bad hair from wearing a headset all day

[Hedley]

running out of fuel enroute (has nothing to do with) BSFC knowledge

Paraphrased your statement somewhat.

A while back, I jumped into a funny old WWII-era aircraft. No checkout,
of course. Sigh. No performance charts, either. Ha ha.

What I did know was:

1) it would probably cruise at just over 100mph
2) it had 24 gallons of fuel
3) it had a 160hp radial engine

and that was it. But because I had a clue about
BSFC, I knew that it would burn about 16 gph in
climb, and 11 gph in cruise. So, if I flew 1.5 hours,
that should be around 17 gallons burned, leaving
7 gallons reserve.

1.5 hours x 100 mph = 150 statute mile legs

zero wind, of course.

And that's pretty much how it worked out.

I guess if you don't mind running out of fuel,
or all you're ever going to fly is Cessnas and
Pipers with inch-think POH's, BSFC isn't very
important.

[Strega]

Hedley,

How did you figure out your start/taxi/take-off fuel burn for your range calculation?

[Invertago]

I guess if you don't mind running out of fuel,
or all you're ever going to fly is Cessnas and
Pipers with inch-think POH's, BSFC isn't very
important.

When I say refer to the POH, I'm assuming we're talking about a modern a/c with a POH, otherwise then yes, if you feel the need to jump into some ol WW2 era plane, then BSFC can be one of several useful means of figuring out fuel burn. Most pilots out there are in aircraft with a POH. If a newly minted PPL came up to me and asked me to teach me everything I could in an hour, BSFC would not be included as in my view it is way down the priority list, if I had all day to teach him, then sure I'd get into it.

Off topic a bit, I never did understand peoples fascination with classic old airplanes (cool WW2 warbirds exempt) I'd think an old tiger moth would be pretty boring. I'd much rather buzz around in a kitfox. I'd take a Cessna 400 over a Cessna 195 anyday of the week. I'd rather a Pitts over a Sopwith Camel any day. Why is old cool when new does everything better? Oh, and give me a chance in a F16 over a P51 as well. Hope that isn't blasphemy. All shinny old planes do is look cool on calendars (did I piss anyone off yet?)

[Hedley]

some ol WW2 era plane, then BSFC can be one of several useful means of figuring out fuel burn

I get stuck test-flying and instructing a lot of (newly
constructed) homebuilts, and they sure don't come
with inch-thick POH's!

Let's say you're presented with a new 90hp homebuilt
with 16 gallons usable that you're supposed to ferry
to Sacramento. Talk to me about how long you can
stay in the air with a decent VFR reserve.

P.S. Apart from their historical significance, you can
learn an awful lot about aviation from old airplanes -
lessons from now long-dead pilots, engineers and
mechanics. Tradition is a big thing in aviation, which
is notoriously conservative, and for a darned good
reason - lessons we've learned over the decades are
how we stay alive today, and tomorrow.

I guess if the goal in life is to be is a SOP monkey in a
white shirt with gold bars on the shoulder, it doesn't
really matter very much.

P.S. I understand it was an astronaut piloting the
Silver Dart replica in Nova Scotia, for the 100th
Anniversary flight of Aviation in Canada. If you talked
to that pilot/astronaut, I'd wager that he understood
the "old airplane" thing.

[U/S]

You could fill it up, fly for an hour then fill it up again. Next leg fly for two hours and do the same thing. I'm guessing that would give you an aircraft specific fuel burn for your climb and cruise portions. That rule of thumb is interesting I certainly haven't heard that before. Moot point now I have my 4inch manual and and an FMS not to mention 4 bars and a banana for my primate side.

[Cat Driver]

How would one explain the difference between a Cessna 400 series and a Beech 18?

Hedley?

Or between a Tiger Moth and a PC12?

Michael P.?

Or between a Piper J3 and a Kitfox?

I will answer the difference in the J3 and a Kitfox, the J3 looks better, flys better and sounds better.

But to each his / her own we all do not like the same things.

When I was a real serious boozer you should have seen some of the choices I made at closing time.

[yfly]

I guess if the goal in life is to be is a SOP monkey in a
white shirt with gold bars on the shoulder, it doesn't
really matter very much.

P.S. I understand it was an astronaut piloting the
Silver Dart replica in Nova Scotia, for the 100th
Anniversary flight of Aviation in Canada. If you talked
to that pilot/astronaut, I'd wager that he understood
the "old airplane" thing.

Requiring BSFC knowledge at an ATPL level is like requiring knowledge of an astro compass. Very few use it and it is better suited to individuals who require the info rather than everyone. Not knowing either doesn't make an individual an inferior pilot any more than does the of wearing gold bars and adhearing to SOP's.

Now, I had the opportunity to train a former astronaut on a post WW2 piston twin and the first thing he asked was "how much fuel am I going to burn?" Then again, I guess he did wears bars and stripes and pretty much lead the way to SOP's.

Out of curiosity, why does everyone on this forum who asks a question take a beating from some egomaniac?

[Chuck Ellsworth]

Out of curiosity, why does everyone on this forum who asks a question take a beating from some egomaniac?

Good question, but then who decides which ones are egomaniacs?

[Chuck Ellsworth]

Not knowing either doesn't make an individual an inferior pilot any more than does the of wearing gold bars

Gold bars are really useful in Africa and a lot of other foreign places if you want to get things done and be able to get back and forth to your airplane.

and adhearing to SOP's.

Adhering to SOP's if fine as long as you know what to do when there is no SOP for a problem you never had before.....like that crew who landed in the Hudson River.

What we really need to do is get someone to write an article on the difference between an aviator and an SOP monkey.

[yfly]

Adhering to SOP's if fine as long as you know what to do when there is no SOP for a problem you never had before.....like that crew who landed in the Hudson River.

What we really need to do is get someone to write an article on the difference between an aviator and an SOP monkey.

Absolutely true. There is no substitute for knowledge and the ability to use it.

In my experience, there are SOP monkeys, but there are far more good pilots that just lack good guidance and a little experience.

[Chuck Ellsworth]

In my experience, there are SOP monkeys, but there are far more good pilots that just lack good guidance and a little experience.

How true, where the problem really gets out of hand is when the ones who can be good teachers get out numbered by the SOP monkeys, and in the small airplane sector that seems to be the problem.

[mag check]

I guess if you don't mind running out of fuel,
or all you're ever going to fly is Cessnas and
Pipers with inch-think POH's, BSFC isn't very
important.

When I say refer to the POH, I'm assuming we're talking about a modern a/c with a POH, otherwise then yes, if you feel the need to jump into some ol WW2 era plane, then BSFC can be one of several useful means of figuring out fuel burn. Most pilots out there are in aircraft with a POH. If a newly minted PPL came up to me and asked me to teach me everything I could in an hour, BSFC would not be included as in my view it is way down the priority list, if I had all day to teach him, then sure I'd get into it.

Off topic a bit, I never did understand peoples fascination with classic old airplanes (cool WW2 warbirds exempt) I'd think an old tiger moth would be pretty boring. I'd much rather buzz around in a kitfox. I'd take a Cessna 400 over a Cessna 195 anyday of the week. I'd rather a Pitts over a Sopwith Camel any day. Why is old cool when new does everything better? Oh, and give me a chance in a F16 over a P51 as well. Hope that isn't blasphemy. All shinny old planes do is look cool on calendars (did I piss anyone off yet?)

I would say that the most notable difference between old cool aircraft, and new regular aircraft, is that the old planes were designed to perform in a specific way, and no corners were cut.
New aircraft can have all kinds of design flaws, and as long as the aircraft will give prior warning of the problem, then no problem.

Examples would be an old champ, in a full slip, there is not enough elevator authority to cause a stall, as the vertical tail blocks out half the elevator. This was designed that way.

Compare that to a new cirrus, that when found to not be recoverable in a spin, simply gives strong pre stall buffet to warn the pilot. One would think that it would make more sense to find out why it won't recover from a spin, but there is no reg that requires it.

[Hedley]

yfly wrote:

why does everyone on this forum who asks a question take a beating from some egomaniac?

Hedley previously wrote:

Tradition is a big thing in aviation

A better question than "Did my ego get stroked today?"
is perhaps "Did I learn something today?"

I suspect that more than a few people reading this, got
an education in the practical application of BSFC. For
absolutely free. And, you also want your ego stroked?

[yfly]

A better question than "Did my ego get stroked today?"
is perhaps "Did I learn something today?"

I must be having a bad day, I got neither.

[mattedfred]

just read this thread

thanks for the lesson hedley

if i was ever taught what BSFC was, i totally forgot it

[Invertago]

Let's say you're presented with a new 90hp homebuilt
with 16 gallons usable that you're supposed to ferry
to Sacramento. Talk to me about how long you can
stay in the air with a decent VFR reserve.

Ball park 2.5hrs + 0.5 reserve... though my first flight would be about 0.5 hours over some nice fields or the airport followed by a fuel measurement. Few aircraft perform perfect newly built. Also, that leaves me the other 24.5 hours to fly off before I start my ferry flight
My first flight with a G1000 DA40 involved manually tracking the fuel every landing while I built up a level of trust with the computerized fuel gauge. I wanted to be sure it was burning what the computer said it was burning. BSFC is great, but I still think it isn't that important to the average weekend warrior. Astro compasses... very important knowledge if you are a aviation museum curator.


To answer Cats question:

How would one explain the difference between a Cessna 400 series and a Beech 18?
Or between a Tiger Moth and a PC12?

The difference is: Beech 18 is a tool while the Cessna 400 is a toy
Tiger Moth sells calendars, PC12 buys time.
And yes the J3 would be more fun then the kitfox because it won't break if you play hard with it and it can pay for itself.


So... look what a shit storm you started I R Instructor lol.