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engine data help

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adam(at)foundationcap.com
Guest

Posted: Wed Jul 19, 2006 8:00 pm Post subject: engine data help

Guys:



I need to develop a power-setting table for an M14P.  The commonly available data is summarized below.

Power       MAP        RPM        %

takeoff       34           2900        99%

Nom I        33           2400        82%

Nom II       32           2050        70%

Cruise I     29           1860        64%

Cruise II    26           1730        59%



Unfortunately, in order to get the "percent power" function to work correctly on my avionics, this isn't  enough data for developing a power-setting table. Does anyone happen to have a diagram showing engine power as a function of manifold

pressure and RPM?  I could only find some less useful charts in the maintenance manual that make no mention of manifold pressure, and the RPM is engine RPM not propeller RPM.



all help welcomed,



Adam

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george(at)gesoco.com
Guest

Posted: Thu Jul 20, 2006 4:57 am Post subject: engine data help

The engine data in the maintenance manual is all I have. The table data you

quote  is what we use for a Yak-52. (and other M14P applications).  The

Maintenance manual data is in engine rpm. The fuel flow is in grams per

hp-hr and Kg per Hr.



George Coy

President

Gesoco Industries Inc.

629 Airport Rd.

Swanton, VT 05488

TEL 802-868-5633

FAX 802-868-4465

Web Site www.gesoco.com

e-mail George(at)gesoco.com

Franklin County Airport (KFSO)



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n395v

Joined: 10 Jan 2006
Posts: 450

Posted: Thu Jul 20, 2006 5:00 am Post subject: Re: engine data help

M14P Power Chart

Power chart from the M14P manual. RPM is for the crankshaft not the propeller (multiply crank RPM by .658 to get prop RPM). Note that these are the sea level, standard day, settings.

Rating	HP	RPM	%	Fuel Consumption

Grams/HP/Hour	Fuel Consumption

Gallons/Liters per hr.	Blower Outlet Pressure (mmHg)

Take Off	360	2900	99%	285-315 	37.7- 41.7 Gal

141.7 - 157.9 Liters	125 - 15 (surplus)

885 - 870 mmHg or 34.8 - 34.2" Hg

Nominal 1	290	2400	82%	280-310	29.8 - 33.0 Gal

112.8 - 124.9 Liters	95 -15 (surplus)

855 - 840 mmHg or 33.6 - 33.0" Hg

Nominal 2	240	2050	70%	265-300	23.4 - 26.5 Gal

88.6 - 100.3	75 -15 (surplus)

835 - 820 mmHg or 32.8 - 32.2" Hg

Cruise 1	.75 of N2	1860	64%	210-230	13.9 - 15.2 Gal

52.6 - 57.6 Liters	735 mmHg +/-15 28.9" Hg (absolute)

Cruise 2	.6 of N2	1730	59%	215-235	11.4 - 12.4 Gal

43.2 - 46.9 Liters	670 mmHg +/-15 26.4" Hg (absolute)

To convert grams per horsepower/hour, first convert grams to pounds/HP (1 gram = .0022046 pounds).

Thus 285 grams * .0022046 = .628311 pounds * 360HP = 226.2 pounds/hour / 6 pounds per gallon = 37.7 gallons per hour. 315 grams * .0022046 = .694449 pounds * 360HP = 250.0 pounds/hour /6 pounds per gallon = 41.7 gallons per hour.

The Blower Outlet Pressure (boost) is always confusing. What they mean by "surplus" is that pressure OVER standard atmospheric pressure, which at sea level on a standard day is 760 mmHg (29.92" of Hg). So add 125 mm (the max SURPLUS) to the 760 = 885 mmHG. The minus 15 would be 870 mmHg. Therefore the manifold pressure at max takeoff power or 2900 RPM will be between 885 and 870 mmHg or 34.8 to 34.2 " Hg as read on your manifold pressure gauge on a standard day at sea level. 

Thus the Blower (boost) increases the manifold pressure over standard atmospheric pressure at this power setting approximately 5 inches of Hg. 

At the Cruise 1 power setting is where you can expect to achieve your best speed and fuel economy. The ".75 of Nominal 2 (240 HP)" = 180 HP at 64% RPM. Fuel consumption at this rating is 210 to 230 grams/hp/hour or 13.88 to 15.21 GPH. That's with a manifold pressure setting of 735 +/- 15 mmHg or 28.35 to 29.52 inches of Hg. So, as a veteran WWII B17 Bomber pilot told me a long time ago, to get the best cruise speed with the best fuel economy, run the engine "oversquare" or make the engine turn the prop and not the prop turn the engine. ie: Lower rpm (in this case 64% or 1860) and higher manifold pressure (28.35 to 29.52 "Hg). In cruise flight, try setting the power to 65% (1880 - 1900 RPM) and 29 "Hg.

M14P Basic Specifications	

Designation -	M-14P

Cooling System -	Air

Number of cylinders -	9, radial, in one row.

Dry mass of basic engine, no accessories, no oil, no mount ring -	214 kg or 471 pounds.

Cylinder order -	Counterclockwise from rear view, #1 at top

Compression Ratio -	6.3

Displacement -	620 Cubic Inches / 10161 cc

Rotation, viewed from rear - crank & prop. -	Left hand.

Propeller reduction gear -	Planetary gears.

Propeller reduction ratio -	.658

Supercharger -	Centrifugal, single stage, mechanical drive.

Supercharger gear ratio -	8.16

Carburetor -	Pressure type.

Start System - 	Compressed air.

Magneto - 	M-9

Max magneto check RPM drop (crankshaft) -	85 RPM (at nominal or first cruise pwr setting)

Compressor -	AK -50A

Oil pump -	Gear, with pressure and scavenger sections.

Pressure and Temperature Limits	

Fuel pressure limits	2.8 to 7.1 PSI, Min. idle 2.1 PSI

Oil pressure, measured at oil pump fitting -	57 to 85 PSI, Min. idle 14 PSI

Oil temp, minimum at engine inlet -	40 C.

Oil temp, recommended at inlet -	50 to 65 C.

Oil temp, max inlet for normal operations -	75 C.

Oil temp, max inlet no more than 15 minutes -	85 C.

Oil temp, maximum at engine outlet -	125 C.

Oil temp, max diff between inlet & outlet -	50 C.

CHT, (#2 & #6 cylinder) Recommended -	140 to 190 C.

CHT, minimum for normal ops. -	120 C.

CHT, min for normal prolonged ops. - 	140 C.

CHT, maximum for prolonged ops. -	220 C. (max continuous CHT)

CHT, max for 15 minutes at TO & Climb pwr. -	240 C. (permissible during takeoff and climb)

Please Note : These numbers are for reference only. Consult your engine operation and maintenance manual for the correct parameters for your engine.

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_________________
Milt

dsavarese(at)elmore.rr.co
Guest

Posted: Thu Jul 20, 2006 5:11 am Post subject: engine data help

The table data that George speaks of is all we have.  If you look on my web 

site, www.yak-52.com on the Power Settings page you will find some 

explanations as well as an additional column for the fuel consumption 

conversion to gallons and liters per hour.

Dennis



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adam(at)foundationcap.com
Guest

Posted: Thu Jul 20, 2006 6:20 am Post subject: engine data help

thanks everyone.  I think I have enough data to build an interpolated curve that will work.

 

Adam



________________________________



Sent: Thu 7/20/2006 6:10 AM






The table data that George speaks of is all we have.  If you look on my web

site, www.yak-52.com on the Power Settings page you will find some

explanations as well as an additional column for the fuel consumption

conversion to gallons and liters per hour.

Dennis



---

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ScottA

Joined: 05 Jan 2006
Posts: 100
Location: Park City, UT

Posted: Thu Jul 20, 2006 7:14 am Post subject: engine data help

No help but curious what instrument you are programming?  What airplane?

Most guys I know of stick with engine RPM instead of converting to prop, but

I do know of a few using prop.

I have not seen any other charts than what you have already found.

Scott



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