Actual Fuel Burn Rates

[GDGR]

I'm sure I am about to beat a dead horse. But, what does everyone get as an actual Fuel Flow rate? I haven't installed my EDM-900 as of yet, but have been meticulous in keeping fuel records, and flight hours on the aircraft. 

Current amounts are: Using Flight (Tach) Time:  8.65 GPH 

                                     Using Airframe (in Flight) time only: 9.77 GPH

Typical flights are under 10,000 ft, usually between 6500-8500 ASL. depending on the MP at altitude, I'll run POH numbers in the 70-75% range which typically shows a Fuel flow of approx 10.5 GPH. 

Am I really using a Gallon (or two) less per hour than expected? 

[Oldguy]

Airspeed for that info?

Any engine monitor at all right now? 

Trying to run LOP or ROP? If you are running 2 gph less than the POH at 70-75%, you may be running your engine in a spot where you would avoid with a full monitor, although conventional wisdom is you are at the edge of an altitude where you probably cannot get your engine in the red box/fin.

[GDGR]

3 minutes ago, Oldguy said:

Airspeed for that info?

Any engine monitor at all right now? 

Trying to run LOP or ROP? If you are running 2 gph less than the POH at 70-75%, you may be running your engine in a spot where you would avoid with a full monitor, although conventional wisdom is you are at the edge of an altitude where you probably cannot get your engine in the red box/fin.

Airspeed is +/- 138 kts. There's a UBG-16 in the plane now, and I"m running 50 ROP. 

[Oldguy]

1 minute ago, GLJA said:

Airspeed is +/- 138 kts. There's a EI G2 in the plane now, and I"m running 50 ROP. 

What I usually read here is the 50 ROP area is not somewhere you want to run your engine for longevity, but I have been known to interpret things incorrectly, so I will let others more knowledgeable ( @M20Doc , @kortopates and others) chime in on this.

[Shadrach]

34 minutes ago, GLJA said:

Airspeed is +/- 138 kts. There's a UBG-16 in the plane now, and I"m running 50 ROP. 

WOT? that is on the slow for a stock F.  I’d expect ~10kts more. I plan for ~140kts when running 25 LOP.

[GDGR]

2 hours ago, Shadrach said:

WOT? that is on the slow for a stock F.  I’d expect ~10kts more. I plan for ~140kts when running 25 LOP.

You and me both.... it is what it is. 

[gsxrpilot]

I'd post data from my flight to Oshkosh, but that would just be mean.  And besides, it's a turbo so not apples to apples.

Can you download the data from your UBG-16? Does it have FF on it? If so, you can upload it to SavvyAnalysis and share the link. The collective here can dissect the data and tell you how it compares to the rest of the cohort.

[GDGR]

3 minutes ago, gsxrpilot said:

I'd post data from my flight to Oshkosh, but that would just be mean.  And besides, it's a turbo so not apples to apples.

Can you download the data from your UBG-16? Does it have FF on it? If so, you can upload it to SavvyAnalysis and share the link. The collective here can dissect the data and tell you how it compares to the rest of the cohort.

Paul, it's a 30 year old POS UBG-16. It shows EGT and CHT, and that's about it. Which is why I have an EDM-900 going in eventually. 

[gsxrpilot]

You'll LOVE the EDM-900. 

We're already flying the most efficient four-place airframe ever certified. A good engine monitor will ensure you get the most efficiency out of the engine as well. It's a match that can't be beat.

[Ragsf15e]

5 hours ago, GLJA said:

I'm sure I am about to beat a dead horse. But, what does everyone get as an actual Fuel Flow rate? I haven't installed my EDM-900 as of yet, but have been meticulous in keeping fuel records, and flight hours on the aircraft. 

Current amounts are: Using Flight (Tach) Time:  8.65 GPH 

                                     Using Airframe (in Flight) time only: 9.77 GPH

Typical flights are under 10,000 ft, usually between 6500-8500 ASL. depending on the MP at altitude, I'll run POH numbers in the 70-75% range which typically shows a Fuel flow of approx 10.5 GPH. 

Am I really using a Gallon (or two) less per hour than expected? 

I track mine vs Hobbs time.  10gph.  I usually run 100 rich of peak but high altitudes, like 10-11, so fuel flow is about 10.5-11.  Ground time brings that down to 10 gallons per hobbs hour, almost exactly.  Yours seems pretty dang close.

[carusoam]

28gph full rich departing...

15gph ROP cruise @10k’

12gph LOP cruise @10k’

WOT IO550 Numbers...  

Best regards,

-a-

 

[Cyril Gibb]

22 hours ago, GLJA said:

Airspeed is +/- 138 kts. There's a UBG-16 in the plane now, and I"m running 50 ROP. 

IAS or TAS?  WOT or not? RPM? Ram air open?

 

 

[GDGR]

On 8/2/2019 at 8:32 AM, Cyril Gibb said:

IAS or TAS?  WOT or not? RPM? Ram air open?

 

 

TAS, with zero wind. WOT and at 75% power, based on POH numbers. So, depending on altitude will determine MP and respective RPM. 

Ram open or closed doesn’t matter really. 75% power is 75% power. 

[M20F]

16 minutes ago, GLJA said:

TAS, with zero wind. WOT and at 75% power, based on POH numbers. So, depending on altitude will determine MP and respective RPM. 

Ram open or closed doesn’t matter really. 75% power is 75% power. 

What are you leaning to?  How are you deriving TAS (the zero wind comment raises question). 

[spectre6573]

At 12000 running 18-18.8 at 2500 I am at 7.5-7.9 at 135kts at 60ish% power

at 10000 running 20 at 2500 I am at 7.8-8.3 at 138kts at 65% power. 

I am happy with the speed because I found I only gain a couple knots or three with 50 ROP and a fuel burned that is 8.5-9.2 gph. The fuel burn isn’t worth the speed gain and I am doing long flights of 5+ hours.

I try to run at peak EGT and 65% power. I do have a JPI900 and have about 65 hours tweaking it and learning what works best for me. 

[GDGR]

18 hours ago, M20F said:

What are you leaning to?  How are you deriving TAS (the zero wind comment raises question). 

Lean to 50 ROP. I have an AME that is anti- LOP. That, and the CHT's typically stay below 380 that way. 

When I say "zero wind", I mean I'll fly one direction, then 180 back and use the average, which works out to usually 138 kts at 75% power. 

Settings are usually:

7500' - 22 MP 25 RPM (Ram closed) 72% from POH 144Kts expected , 24 / 24 (Ram Open) - 74% from POH  146kt expected

10,000' - 19MP 26 RPM (Ram Closed) 65% 141 expected , 21 MP 25 (Ram Open) 68% 146 expected

 

TAS is based off of GPS.  

 

[Hank]

26 minutes ago, GLJA said:

TAS is based off of GPS.  

My GPS gives groundspeed, unless I go to a back screen and enter altimeter setting and OAT. Such is life with steam gauges . . .

[GDGR]

21 minutes ago, Hank said:

My GPS gives groundspeed, unless I go to a back screen and enter altimeter setting and OAT. Such is life with steam gauges . . .

You would be correct.... Brain freeze there. I meant GS. 

[Hank]

Just now, GLJA said:

You would be correct.... Brain freeze there. I meant GS. 

The groundspeed envelope for my C, at altitude with pretty much the same power settings and IAS [usually 140-145 mph], is 68-186 knots. According to my owner's Manual, I should expect 158-164 mph [137-142 knots]. So neither GroundSpeed nor Indicated Air Speed is any good for determining performance.

Thus the need to determine True Air Speed. Without scrolling, clicking and hoping to get everything right [my OAT is in ºF but the GPS wants it in ºC], there's a quick way to estimate TAS:  just look at your Airspeed Indicator and add 2% for every 1000' shown on your altimeter.

For 144 mph at 7500 msl, that would be 2 x 7½ = 15%, so 144 + 15% = 165.6 mph with a calculator, or 144 + 14 + 7 + a smidge = 165+ using my head. Close enough.

Try this and see how it compares to your Performance Charts.

Another neat thing about 7500 msl--the 15% conversion is also the same as mph-->knots, so 144 mph indicated at 7500 is also 144 knots True Air Speed.    Makes the math easy.

[M20F]

28 minutes ago, Hank said:

So neither GroundSpeed nor Indicated Air Speed is any good for determining performance.

He is using a two way GS calculation “I mean I'll fly one direction, then 180 back and use the average, which works out to usually 138 kts at 75% power“ to determine TAS which Erik or somebody can explain the % of error versus a three way but you can derive TAS through ground speed.  

[1964-M20E]

8.5 to 9.0 GPH at 9000 to 11000 feet LOP, WOT, 2 hour plus flights.  When it comes to 1 hour flights 10GPH.  This has been proven to myself over many flights and many years.

With 54 gallons on a long flight I plan for 6 hours of engine running time that is before the engine stops making noise.

As for flight time the most I have done or will plan for is 5 hours with 9 to 10 gallons remaining.   I run the first tank for 1 hour or 10 gallons then I run the second tank dry so all remaining fuel is in one tank.  If I know I will be shooting an approach at my destination with IMC approaching my minimums then I will make a planned stop 1 to 2 hours before my destination to top off the tanks and revaluate my plan.

[skydvrboy]

2 hours ago, GLJA said:

Lean to 50 ROP. I have an AME that is anti- LOP. That, and the CHT's typically stay below 380 that way. 

I'm puzzled by this statement.  First, why would anyone who knows how our fuel injected engines operate be anti-LOP?  I assume an AME is someone know knows about these engines?  Second, why run your engine that hot?  Engine performance charts will show that your CHT's would be cooler at peak, and even cooler LOP.  Just this weekend I was cruising 25 LOP at 8500' (60F OAT) and my CHT's never got above 350.

[Ragsf15e]

^^^what he said.  50ROP is the worst place to be.  100 ROP or 20 Lop would both be cooler.  Lean of peak is usually much cooler.

[Bob_Belville]

I fly an E, IO 360.

I have 64 gallon bladders and a 930 EDM.

I just flew from Klamath Falls OR to Stow MA. in 4 legs. I fly at 2350 rpm, full throttle and 8.2 gph. Cruise is usually 140 ktas.

From Garmin Pilot Logbook.

Klamath Falls to Grand Canyon with a brief stop: 5.5 hours, 664 nm, 47.5 gal.

Grand Canyon to KPWA (Oklahoma City) 5.7 hours, 736 nm, 47.3 gallons.

KPWA to KMRN (Morganton NC) 5.7 hours, 794 nm, 50 gallons.

MRN to 6B6 (Stow MA) 4.6 hours, 650 nm, 39.3 gallons.

Total 21.5 hours, 2844 nm, 184.1 gallons.

That’s 8.56 gph avg. (The first hour is typically 12 gallons climbing to 9000’.)


Sent from my iPad using Tapatalk

[Cyril Gibb]

11 hours ago, GLJA said:

When I say "zero wind", I mean I'll fly one direction, then 180 back and use the average, which works out to usually 138 kts at 75% power. 

Two way 180 degree average will only be correct if you have 0 crosswind component.