Fuel consumption test runs

[Michael Wellenzohn]

I did fuel consumption test runs with 55%, 65% and 75% at 3000 ft and 6000ft as well as 9500 ft (55% & 65%). What did you guys measure or is there a chart to see fuel consumption over altitude for different power settings?

This is how I did it.
1) Set power e.g. 2300 RPM, 20.7 MAP which gives me 55% HP
2) Autopilot alt hold e.g.. 3000ft
2) I lean slowly about .2 gal/2min until the last EGT peaked and runs about 15F LOP stayed with this setting to record speeds and fuel flow. (My injection nozzle restrictors still have a gami spread of about 0.9 gal).

My results are:

55% pwr
3000 ft 9.11 gal/h 134 TAS kt
6000 ft 9 gal/h 140 TAS
9000 ft 9.25 gal/h ? 154 TAS

65% pwr
3000 ft 10.7 gal/h 144 TAS
6000 ft 10.57 gal/h 157 TAS
9500 ft 10.4 gal/h 160 TAS

75% pwr
3000 ft 12.4 gal/h 162 TAS
6000 ft 12.28 gal/h 167 TAS

thanks
Michael

 

[jimgreen]

what unit forTAS? knots?

 

[Michael Wellenzohn]

yes TAS is in knots

 

[paul330]

Some impressively low fuel flows!

I'd have to say that the 55%/9k numbers are an anomaly. Also, is it wise to be running LOP at 75% power?

 

[RV10inOz]

First of all let me deal with an OWT Sad to still be doing this.......but hey everyone learns some day.

There is nothing at all wrong with LOP at or well above 75% power if you are at the appropriate LOP setting. In fact being 50LOP at high power is far better than being 50, or even 100 ROP.

Michael,

First of all....get the GAMI spread sorted first of all. Send your data to John-Paul Townsend at GAMI his email is john-paul'at'gami.com just replace the 'at' with an @ so he does not get spammed. He will sort you out, tell him I sent you, and I promise you will be looked after.

Next thing, do a GPS box test to prove your static is dynamically correct. Refer the search function and look for Kevin Hortons posts for details.

As for your actual power settings when you were LOP.... well they go like this, USGPH x 14.9 = HP, so take that and multiply by 100 and divide by 260 that will give you % power. Unless you have a Dynon or an Auracle I can't be sure the % power is correct.

55% pwr
3000 ft 9.11 gal/h 134 TAS kt 52%
6000 ft 9 gal/h 140 TAS 52%
9000 ft 9.25 gal/h ? 154 TAS 53%

65% pwr
3000 ft 10.7 gal/h 144 TAS 61%
6000 ft 10.57 gal/h 157 TAS 60%
9500 ft 10.4 gal/h 160 TAS 59.6%

75% pwr
3000 ft 12.4 gal/h 162 TAS 71%
6000 ft 12.28 gal/h 167 TAS 70%

The RV10 is an amazing plane, I have about 900 hours on hours and runs like a dream.

Power setting charts....by Advanced Pilot Seminars
________________________________________
Red Box = No Fly Zone
• At and below about 60% power, there is no red box. Put the mixture wherever you want it.
• At about 65% power or so, 100ºF ROP to Peak.
• At about 70%, 125ºF ROP to 25ºF LOP.
• At about 75%, 180ºF ROP to 40ºF LOP.
• At about 80%, 200ºF ROP to 60ºF LOP.
________________________________________


________________________________________
Outside the Box
• At 65% power, use richer than 100 ROP, or leaner than peak EGT.
• At 70%, use richer than 125ºF ROP, or leaner than 25ºF LOP.
• At 75%, use richer than 180ºF ROP, or leaner than 40ºF LOP.
• At 80%, use richer than 200ºF ROP, or leaner than 60ºF LOP.
________________________________________

I would strongly encourage you to take the online course too. http://www.advancedpilot.com/onlinecourse.html

Disclaimer: And just because some smarty pants will try to criticise.....no if you sign up for the online course there is no dollar in it for me!

Any questions, PM me.

 

[Michael Wellenzohn]

Great feedback, thanks to all.
Mike