MPG

[nels]

I will probably be flying from Cincinnati to Phoenix next month with my friend and instructor so I might finally get enough hours in for insurance requirments. My plane is a 66 E model with the 201 windshield, two blade prop and no other mods. I'm curious as to experiences others have had with similar planes as far as fuel usage on long cross countries. I guess it would be best to assume 10k ft, zero wind, one hour of reserve. It looks like the trip will be about 1400 miles one way. Doing a hipothetical flight plan with no stops says I should use about 100 gal with no wind. That is 14 nautical mpg. The fuel stops, which were not included, should bring that number down to even a lower number. So, real world, how far can you guys go on a tank of gas with no wind consideration, including take off and landing with maybe an hour reserve? Any suggested techniques to improve the mpg will also be appreciated including lop operation.

[TTaylor]

LOP is the only way to go.  I am guessing you can get 144 knots at 9 gph with your modified E, maybe better.   Not sure which tanks you have.  But flying with a 45 minute to one hour reserve you should be able to do nearly five hour legs depending on your tanks. Do you have a fuel flow meter? That is a must with the IO-360.

 

I do a gentle climb (~95 to 100 knots indicated) leaning continually to 100 ROP as I climb and then lean to 9 gph once in cruise. 

 

Things that will help fuel economy:

Less  weight

Plan for winds and pick your best safe altitude (Especially going west).

Fewer stops

LOP cruise

 

I just got back from a trip to California today and averaged 16 nmpg with a stock "F" that only does about 138 knots at 8.6 gph. 

[N601RX]

Glad to see you got your plane back flying!

[nels]

Glad to see you got your plane back flying!

Thanks, it was a long hard battle and a lesson learned!

[nels]

LOP is the only way to go.  I am guessing you can get 144 knots at 9 gph with your modified E, maybe better.   Not sure which tanks you have.  But flying with a 45 minute to one hour reserve you should be able to do nearly five hour legs depending on your tanks. Do you have a fuel flow meter? That is a must with the IO-360.

 

I do a gentle climb (~95 to 100 knots indicated) leaning continually to 100 ROP as I climb and then lean to 9 gph once in cruise. 

 

Things that will help fuel economy:

Less  weight

Plan for winds and pick your best safe altitude (Especially going west).

Fewer stops

LOP cruise

 

I just got back from a trip to California today and averaged 16 nmpg with a stock "F" that only does about 138 knots at 8.6 gph.

My tanks are the standard 52 gal versions. I've done no lop flying but hope to try it on this trip. I might even slow it down some to try to improve fuel consumption/mpg. We're in no real hurry.not sure how much that will help but from what I've read it sounds like about 135 mph is the optimum speed for max mpg(?).

[nels]

LOP is the only way to go.  I am guessing you can get 144 knots at 9 gph with your modified E, maybe better.   Not sure which tanks you have.  But flying with a 45 minute to one hour reserve you should be able to do nearly five hour legs depending on your tanks. Do you have a fuel flow meter? That is a must with the IO-360.

 

I do a gentle climb (~95 to 100 knots indicated) leaning continually to 100 ROP as I climb and then lean to 9 gph once in cruise. 

 

Things that will help fuel economy:

Less  weight

Plan for winds and pick your best safe altitude (Especially going west).

Fewer stops

LOP cruise

 

I just got back from a trip to California today and averaged 16 nmpg with a stock "F" that only does about 138 knots at 8.6 gph.

Not sure what you mean by plan for the winds and pick __"your best safe altitude (especially going west)"

[Hank]

He means check the forecast winds aloft, and select the altitude that provides both adequate terrain clearance (2000' or more in the mountains) and meets MEAs if IFR or radar coverage if not that has most favorable winds. I went to Cody, WY at 127 knots average, and came home at 151; this us a typical wind scenario blowing from the west. When you come back, consider going higher for tailwinds.

Plan we'll, fly safe and have a great trip!

[jkgyr52]

Nels,

 

I have hundreds of ~ 600 nm x-c legs in Mooneys and here are the things I do to improve efficiency:

 

Does your POH have a max range table?  My past E, G,  J , and K models have had really extended ranges at 35-45% power settings. 

 

Try staying on the upwind side of any mountain range for free lift.  Avoid flying close to mountains when on the downwind side.  Fly the valleys.

 

When faced with winds > 10-15 knots it is probably better to stay as low as it is safe.

 

Pick the highest elevation fuel stops. 

 

Plan for the lowest elevation route when going upwind.

 

If your engine runs smooth when LOP, go for it.

 

Carry several plastic old fruit juice bottles to store urine and wash the bugs off your leading edges!

 

Have fun

[201er]

Word of advice: always plan on a headwind

[MB65E]

Hi Nels! Have a great trip! I've had fun out west in a number of airplanes and helicopters! Including our E. With the old engine we did about 140kts with the 201 windscreen and a few other mods. I'd plan on at least 10.5 gph. 3 to 3.5 was good enough for me. Especially when your in west Texas getting slammed by a 35-40 kt head wind. There are usually only 2 ways to get to PHX. 1. Via ELP and 2. ABQ. I would not reccomenned ABQ in the summer. DA's can get pretty hi. I usually go south unless >200hp. Also might point out that stretching mileage out west is really not wise, borderline stupid. To be honest, west of Abline TX/ even Dallas, there are not many places to stop if your short on gas. Good stops out west over the last 5 years have been Liberal KS, Hutchinson KS, gainsville TX, Amarillo Tx TAC air and Buffalo Wild Wings next to the Fairfield, Hobbs NM gas only, Double eagle AEG, 5t6 Donna Anna -gas, marana AZ, Most have good XWind options.

Just my 2c. All good stops if needed.

Also for JKgyr52. I never thought about the efficiency of using a higher elevation airport for fuel stops. I guess that works if RW. Requirements are met. I guess I just try and stay low most of the time.

Fly safe!

Matt

[MB65E]

Oh and call the airport to check for gas. Don't ever use the chart for fuel purposes!!!!!!!!!!!!

Still ugggg... And if your in any thing French or anything with an odd fueling port make sure you bring your own fueling nozzle! I have pumped 85 gal of jet A thru a funnel by myself! I Kept the funnel too!

[garytex]

With a Jpi or similar, and familiarity with the red box, and your willingness to slow down 5 or 10 mph you should see near 20 mpg statute running lop at altitude. Try around 8.5 gph.

Gary

[Z W]

What's wrong with 14 NMPG?  In a straight line?  At 165 MPH?

 

As others have posted, you can do a little better by flying high and reducing power settings (RPM, throttle, and mixture) as much as you can tolerate.

 

Myself, I hate watching my groundspeed decrease.  I like to go fast.  

 

You're in the most efficient 4-place piston single, except for maybe a J or K model, depending on some other factors.

[Shadrach]

Planning for 10gph will keep you out of trouble. If you run Peak or LOP at altitude you should do much better. If you're well instrumented then you can use can really dial in max range per tank, if not, stick with 4.5hr legs, max. I have 64 gals usable in my F and I do 5.5 hour legs when on solo XCs. I always land with >10 gals on board. I conservatively figure my max no wind range with reserves at around 800NM. In an E I would suggest you limit yourself to 650nm until you get to know the nuances of the plane...

[TTaylor]

Nels,

 

All the comments above are good.

 

I guess I would add that while MPG is good, Cost per mile ($PNM) is probably a better way to look at the numbers.  Pure mpg may cost you more because of the hourly cost on the plane as well as the fuel cost.  I estimate that my hourly cost is about $30 per hour dry (This does not include insurance, annual or hangar, never calculate the real numbers or you will stop flying ) for engine, prop, tires, oil, etc.  So now you factor in your hourly cost with cost of fuel per hour to figure your best flying speed.  I tend to use about 8.5 to 9 gph as the range where I get best economy with reasonable speed (we are flying Mooney's!). 

 

Have fun on the trip.

 

Tim

[flyboy]

Ladies and gentlemen, we have a winner,

 

The best advice ever given on this or any other forum. (Drum roll please)

 

TTaylor from Logan Utah with:

 

 "never calculate the real numbers or you will stop flying  "

 

I plan on 10 GPH at 150 MPH = 15 MPG in my old M20B with an O360, perhaps someday I will hang an IO360 and that will improve things.

[nels]

Thanks for all the input. This should be a fun trip, I hope to learn some about my plane on the way out and back. I do want to try lop but don't want to try it if I'm at 3500 ft but if I go up around 6.5 I'll give it a shot.

We may work our way back home via Denver. I have two kids out there and my daughter wants me to baby sit her fifteen lb dog while she and her husband are on vacation. A little concerned about hauling the dog back to Cincinnati since it's never been on a plane. Also from Phoenix to Denver is a lot shorter going over Albuquerque than going way south to Demming then heading north again. It was mentioned that the short route is hazardous in the summer. What about in January? What are the particular problems taking that route?

[DrBill]

I too plan on about 15mpg at 10K + but got >20MPG to OSH and back. 2400 and 24inches, 10-20 LOP. I planned for 3.5 hr first leg and shorter 2nd leg. I have a 3 hr bladder. We would look for airports with cheap gas (airnav.com). All flying was done IFR and we skirted CHICAGO around the south - southwest route. Get over 10K and enjoy the speed and lean cruise if the winds work for you.

BILL

[aaronk25]

Thanks for all the input. This should be a fun trip, I hope to learn some about my plane on the way out and back. I do want to try lop but don't want to try it if I'm at 3500 ft but if I go up around 6.5 I'll give it a shot.

We may work our way back home via Denver. I have two kids out there and my daughter wants me to baby sit her fifteen lb dog while she and her husband are on vacation. A little concerned about hauling the dog back to Cincinnati since it's never been on a plane. Also from Phoenix to Denver is a lot shorter going over Albuquerque than going way south to Demming then heading north again. It was mentioned that the short route is hazardous in the summer. What about in January? What are the particular problems taking that route?

Just figure out what mp you would have at 6.5 at wide open and reduce your throttle to that value at 3,500 and lean it to LOP. Your engine will think it's at 6.5.

[201er]

Just figure out what mp you would have at 6.5 at wide open and reduce your throttle to that value at 3,500 and lean it to LOP. Your engine will think it's at 6.5.

But your wing and prop won't! Generally any altitude that gives you 27"MP or less is a no-brainer for LOP ops. Just bring prop back to 2500RPM or less and mixture below 10GPH and you're in the ballpark. Use EGT to optimize that.

[garytex]

The place to learn Lop ops is at 8500 and up. Unless it's really cold you can't get enough oxygen in your engine to hurt it with fuel above 8500 feet. So when you get up high start fiddling with the red knob until you find a speed and vibration level and fuel flow that makes you happy.

Gary

[aaronk25]

But your wing and prop won't! Generally any altitude that gives you 27"MP or less is a no-brainer for LOP ops. Just bring prop back to 2500RPM or less and mixture below 10GPH and you're in the ballpark. Use EGT to optimize that.

I get it but people new to LOP opps get anxious at seeing the MP high at lower altitudes and besides if your not in a hurry pulling back to 25" or 26" and running 20 LOP will yield better mileage than running full throttle and say 50lop. Obviously once at 4500 or above wide open.

Just my thoughts.