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Thread: fuel burn comparisons or wishes?

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    Member tboehm's Avatar
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    Default fuel burn comparisons or wishes?

    We have had a few different threads going compairing planes and their abilities but I thought that it might be interesting to see some thoughts strictly on fuel burns. What do you want or like for your plane? What is the highest payload capacity for the lowest burn rate. At what burn rate do you find things becomming cost prohibative for the cost conscious flyer. What do you gain or lose having the STC for auto fuel? Any additional thoughts along this line of thinking?

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    Well, it depends on the mission (how many times do you hear that )

    If you are flying for fun, boring holes in the sky, then fuel burn is a major consideration.

    If you are going from point A to point B, then MPG is more important than GPH.

    My plane burns about 7.5-9 GPH in cruise depending on OAT (winter or summer) and altitude. I typically cruise at about 100 to 105 knots because of a climb prop.

    That's about 13-14 mpg.

    There are planes that burn upwards of 14 GPH (ouch!), but fly much faster doing it. They meet or exceed my MPG. Are they any more expensive to fuel? Not really, if you are traveling somewhere.

    In the end, IMO, fuel burn is pretty far down on my list of considerations when buying a plane. I'd be more concerned about recurring and potential unplanned maintenance costs of a big-bore aircraft engine compared to something smaller.

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    Your funny, you did write cost conscious flyer? If you really look at it , it cost about the same to carry wt. a given distance if you gross out the load in every plane you compare. This changes if you don't use your plane to its design limit.also the diference is taken up in the performance diferences required to haul the load(short field, mountains, etc). your question can't be answered, way too many varribles.

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    A beaver is too much burn for me right now.
    Ten years ago a 150 cub burnt too much for me.
    Directly proportional to your paycheck.

    Call an engine rebuilder and see what they say about autogas. May stop u from burnin it. Did me.

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    You don't want to fool with autogas, the last thing you want to put in your airplane is a fuel that has ethanol in it. Alcohol mixes with water and its not a good thing as far as airplanes go. As for fuel burn, its how much I want to haul and how far I have to haul it. While a Super Cub my have a low gph burn, the cost of fuel per pound of stuff can be high because you can't carry much. While a PA-32-300 @ 15 gph may sound a bit on the high side but you can in most case fill the tanks, the pilot and about 900 or so lbs give or take a little so the fuel burn per lbs of stuff would be a bit lower because you can take more. On the other hand you are not going to go in a Six where a Super Cub can go. Its one of the reasons why the farther away you are from things like reasonable sized airports, the prices you pay either to get there or to have stuff shipped goes up and some times way up. Airplanes are not cheap, to own or to fly, they never were. You have to look real hard at what your needs really are vs gee it would be so cool to have one of those.

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    Member tboehm's Avatar
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    Some of the point are well stated and I have to agree. Maybe I didn't word things very well but it would be interesting to hear what folks are getting and if they did anything to get it. Or. I own a M6 and it gets X but I would rather have a M5 because it gets X or my plane has a 160hp in a X and it burns X and has X abilities but I want to but a 180hp in it and it would do to this...

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    I put a big motor on my 180 and flight plan for 16gph. That's about $65-70 per hour just in gas. I could throttle back and save fuel but that defeats the fun of the big motor so I run it hard. I still can't wipe the smile off my face.

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    i got a 185 and am in the same boat as mr pid, love the power and plan on 16 gal/hr, I love this plane!!

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    Member algonquin's Avatar
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    my C-180 burns 14.5 gph at gross, I averaged it over the trip up from the east coast this spring. Flown at varring alt.s 2000 to 11,000. The other side is light you can throtle back to 12 gph or so. I would guess that the 520 conversion is better on fuel/speed/load but the 30-40,000 to convert or the price diference to buy a 185 doesn't off set the price, unless you need the power for the mission. Sooo I do beleive we have returned to the original point of departure, so to speak.

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    There is fuel burn per hour and then there is fuel burn per mile if you are actually going someplace.

    My little PA-11 with a C-90 burns 4 gallons an hour at low cruise, 5 gallons an hour at high cruise and 3 to 3.2 gallons per hour doing water taxi and pattern work.
    So for float-plane instruction it works just fine. And she will carry two 200 pound pilots, fuel and survival gear for 4 hours with reserves. (legally)
    BUT: she only cruises along at 80-85 mph in cool weather, (on floats) or 70-75 mph at slow cruise.

    So at low cruise I am getting 18.75 miles per gallon.
    at High Cruise I am getting 17.0 miles per gallon, in the CUB.

    My old Super Cub did the same speed while burning 7 to 8 gallons an hour. So it was only getting 10-12 miles per gallon depending on how it was loaded.


    I used to have a C-150 with a 0-320 in it.
    It burned about 8 gallons an hour at high cruise. WITH WAS 135 mph. = 16.8 mpg
    But at 125 mph she would only burn 7 gallons per hour. =17.8 mpg


    I also regularly fly a C172 with a 180 horse conversion (fixed pitch cruise prop). It will lean down to 6.5 to 7.0 gallons per hour at about 99 knots or 114 mph. Which comes out to 17.5 miles per gallon with 3 people in the plane

    On the other hand,,,,
    I have been instructing in another guy's Scout with a 180 horse and a constant speed prop. That darn thing burns gas like there is no tomorrow. 10 to 12 gallons an hour. If we really work on it we can get it down to 9.5 per hour. But it is still only hauling two people (very uncomfortably) and it lands like a sack of potatoes.
    It will cruise at 100 to 110 mph while leaned,,, sometimes....
    So that thing is only getting 11.5 miles per gallon.
    Floatplane,Tailwheel and Firearms Instructor- Dragonfly Aero
    Experimental Hand-Loader, NRA Life Member
    http://site.dragonflyaero.com

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    Algonquin said it right earlier. It costs about the same $ per pound/mile for payload. Therefore it doesn't make sense for a guy with a fishing pole and a sandwich to select a 185 when a Cub will fit the bill, assuming he has the time to fly at 90mph. If you're hauling 1500#? The 185 makes a lot of sense. That's a lot of trips in that PA-11. If time is money? Maybe the faster plane makes sense. If weight is money? Different answer. If you just want to fly around on nice days for the sake of having fun? Different answer again. Pick a plane based on your needs. Then, like most owners, your needs will evolve and you'll be back in the plane market.

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    And now the EPA has announced they have no firm time line for the end of 100LL.... so we all have fuel TO burn.

    My old 7ECA with the O-235-C1 motor burned 8 gph consistently at 85 kts. 12.2 mpg

    The CRJ200 I'm flying now burns 2800pph in cruise at 460 kts. Let's see, that's 418gph at 529mph... 1.27miles per gallon! Or, not counting crew, 63.5 seat miles per gallon. ;-P

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    Quote Originally Posted by BH206L3 View Post
    You don't want to fool with autogas, the last thing you want to put in your airplane is a fuel that has ethanol in it. Alcohol mixes with water and its not a good thing as far as airplanes go. As for fuel burn, its how much I want to haul and how far I have to haul it. While a Super Cub my have a low gph burn, the cost of fuel per pound of stuff can be high because you can't carry much. While a PA-32-300 @ 15 gph may sound a bit on the high side but you can in most case fill the tanks, the pilot and about 900 or so lbs give or take a little so the fuel burn per lbs of stuff would be a bit lower because you can take more. On the other hand you are not going to go in a Six where a Super Cub can go. Its one of the reasons why the farther away you are from things like reasonable sized airports, the prices you pay either to get there or to have stuff shipped goes up and some times way up. Airplanes are not cheap, to own or to fly, they never were. You have to look real hard at what your needs really are vs gee it would be so cool to have one of those.
    Are you sure you've flown Super Cubs with real loads? And, I wonder why no one has yet mentioned engine management and TBOs? There may be still a few things for some of you to think about, maybe ---------

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    Quote Originally Posted by BH206L3 View Post
    You don't want to fool with autogas, the last thing you want to put in your airplane is a fuel that has ethanol in it. Alcohol mixes with water and its not a good thing as far as airplanes go. As for fuel burn, its how much I want to haul and how far I have to haul it. While a Super Cub my have a low gph burn, the cost of fuel per pound of stuff can be high because you can't carry much. While a PA-32-300 @ 15 gph may sound a bit on the high side but you can in most case fill the tanks, the pilot and about 900 or so lbs give or take a little so the fuel burn per lbs of stuff would be a bit lower because you can take more. On the other hand you are not going to go in a Six where a Super Cub can go. Its one of the reasons why the farther away you are from things like reasonable sized airports, the prices you pay either to get there or to have stuff shipped goes up and some times way up. Airplanes are not cheap, to own or to fly, they never were. You have to look real hard at what your needs really are vs gee it would be so cool to have one of those.
    I know not everyone on here is in Alaska but where are you getting mogas with ethanol? Not up here?

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    Quote Originally Posted by AK-HUNT View Post
    A beaver is too much burn for me right now.
    Ten years ago a 150 cub burnt too much for me.
    Directly proportional to your paycheck.

    Call an engine rebuilder and see what they say about autogas. May stop u from burnin it. Did me.
    Well mine says stay far away from 100ll and burn as much mogas as I can find. Can't always do that of course but when I can it sure saves on TCP. If you are talking about the bottom end it doesn't know 100ll from moonshine.

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    Quote Originally Posted by Alaskaflyer331 View Post
    Well mine says stay far away from 100ll and burn as much mogas as I can find. Can't always do that of course but when I can it sure saves on TCP. If you are talking about the bottom end it doesn't know 100ll from moonshine.
    Maybe I missed it, what are you flying? Care to share some insights as to what you are getting by using the mogas? Sorry for the ignorance but what is TCP?

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    TCP is an aftermarket fuel additive that guys use to scavenge lead. Old engines were designed to run avgas when avgas had less lead than it does now. Some planes get lead deposits on the spark plugs. On the other hand, airplane engines are designed to have some lead to help their valve seats. If a plane was having lead deposit issues I'd blend mogas and avgas before I bought an expensive can of TCP to add to my expensive avgas. I know guys who blend. Personally I've always used avgas and have never had a problem with lead deposits.

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    Hear, hear!

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    Quote Originally Posted by tboehm View Post
    Maybe I missed it, what are you flying? Care to share some insights as to what you are getting by using the mogas? Sorry for the ignorance but what is TCP?
    The TCP was explained very well by Mr. Pid. As to what I am getting? Just under a dollar a gallon savings to use in other pursuits plus less lead fouling, plus less $ for TCp, without which I couldn't reasonably burn 100LL at all when I have to.

    I fly behind a Franklin engine.

    Opinions about mogas are like, well, you know what. Every pilot has one. I just know for forty bucks savings each tankful I'm willing to risk a few old wives tales. I wager that - considering what my engine was originally designed to run on - mogas is no worse than 100LL and might just be better. I run about every third tank on 100LL due to my traveling somewhere away from home and having to. Engine likes that so far.

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    Quote Originally Posted by Alaskaflyer331 View Post
    The TCP was explained very well by Mr. Pid. As to what I am getting? Just under a dollar a gallon savings to use in other pursuits plus less lead fouling, plus less $ for TCp, without which I couldn't reasonably burn 100LL at all when I have to.

    I fly behind a Franklin engine.

    Opinions about mogas are like, well, you know what. Every pilot has one. I just know for forty bucks savings each tankful I'm willing to risk a few old wives tales. I wager that - considering what my engine was originally designed to run on - mogas is no worse than 100LL and might just be better. I run about every third tank on 100LL due to my traveling somewhere away from home and having to. Engine likes that so far.
    You guys are helping me learn alot and I appreciate it.

    flyer331 - What hp is your Franklin and what do you have it strapped too?

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