I am toying around with swapping an engine into an existing model and would like to get it as accurate as possible. Is there a reference (or references) you all would recommend explaining the config files and how they relate to the "real world"?

Rick

On this note, I have a nice C150 I would like to add just a little more kick to without drastically upsetting other performance factors.
Would swapping in the default C172 or C182 do the trick? I'm only looking to boost the cruising speed by 25-30kts. It's currently at around 90, and I would like to  have it at 120 or so.

They didn't seem that different really, except for the lines I've posted here, the rest of the engine data in the .cfg was identical. Maybe I want something in between these two then? The one I'm wanting to use is only a 4cyl. also, I figured that would be reasonably realistic, at least within the bounds of do-ability. I think engine swap was the wrong terms to think in, it's more like a cylinder bore job.
Would a 6cyl even fit under the hood of a 150?

This is the engine section of the C150:

[piston_engine]
power_scalar=1.00000
cylinder_displacement=50.00000
compression_ratio=7.0000
number_of_cylinders=4
max_rated_rpm=2750.00000
max_rated_hp=100.00000

And this is from the default FS9 C172

[piston_engine]
power_scalar = 1.0                              //Piston power scalar
cylinder_displacement= 90.0                     //Cubic inches per cylinder
compression_ratio= 8.5                          //Compression ratio
number_of_cylinders=4                           //Number of cylinders
max_rated_rpm= 2700                             //Max rated RPM
max_rated_hp= 180                               //Max rated HP

Ok.. here's what I'd do:

Swap the key engine elements...

Add 150lbs to both the empy weight, and max weights, but leave the CG alone (pretending that your sandbag is the perfect weight, placed perfectly)...


Increase the prop MOI slightly and and icrease its fixed pitch by a few degrees (this would be the custom prop you'd probably need)(the extra HP would run wild on the light, 150 prop)

Test and tweak     if it's only a little bit harder to fly, I'd leave it like that...  

Lastly, edit the paint-job to have "EXPERIMENTAL" posted clearly near both doors..  And edit the panel bitmaps with a similar warning..

Flies like a dream, and got the little bit of extra speed! Thanks for the help. I think it's even easier to land now also.

Brett_Henderson wrote on Dec 11^th, 2008 at 7:05am:


The paint shop is WAAAY ahead of the mechanics on this project.

http://i34.tinypic.com/2e4wy93.jpg

I'm not a pilot, so this all an exercise for my entertainmentand I am looking to replace the the AEIO-360-A1D configuration for an AEIO-540-K1A5.

I made changes to cylinder displacement, HP and compression ratio. I also changed the pitch range of the prop so that it does not run over 3K. I have adjusted the aircraft weights by an additional 137 lbs and will be looking at the aircraft body model later to look for the additional 10" I'll need for the length of the motor. I was considering reducing the fuel available to offset the engine weight.

It's a wild ride as it is... throttle touch has to be light or it runs away with you. The IAS pegs at 230 and will fly there a LONG time before the craft comes apart. The "never exceed" speed in the reference is 210 so it feels unrealistic. Can I bump this so that overspeed causes tragic results sooner? What else? How is fuel consumption calculated?  Should I change props? Stay with the constant speed or change to a fixed pitc? Two blades? Three? Where can I adjust for the effects of torque in the config file? Will Luke and Laura ever find true happiness together?



Here is where I am so far, I really appreciate you taking the time to look.  Happy flying!

Rick




[piston_engine]                                 //                          LYC AEIO-540-K1A5
power_scalar = 1.0                           //                          Six-cylinder air-cooled horizontally opposed engine
cylinder_displacement = 130             //90                       Bore: 5.125 in
compression_ratio = 10                    //original: 8.7          Stroke: 4.375 in
number_of_cylinders = 6                  //6                         Displacement: 541 cu in                    
max_rated_rpm = 2700                   //original: 2700        Weight: 440 lb
max_rated_hp = 322                        //200
fuel_metering_type = 0
cooling_type = 0                                
normalized_starter_torque = .32       
turbocharged = 0                  
max_design_mp = 0                  //29.9
min_design_mp = 0                  //9
critical_altitude = 0
emergency_boost_type = 0
emergency_boost_mp_offset = 0
emergency_boost_gain_offset = 0
fuel_air_auto_mixture = 0
auto_ignition = 0
emergency_boost_duration = 0
max_rpm_mechanical_efficiency_scalar = 1
idle_rpm_mechanical_efficiency_scalar = 1
max_rpm_friction_scalar = 1
idle_rpm_friction_scalar = 1

[propeller]                                       //                    Hartzell 81HC-C2YK-4CF/FC7666A-2 constant speed prop
thrust_scalar = 1
propeller_type = 0
propeller_diameter = 6.1
propeller_blades = 2
propeller_moi = 3.4
beta_max = 50     //original: 65
beta_min = 15     //original: 15
min_gov_rpm = 405
prop_tc = 0.01
gear_reduction_ratio = 1
fixed_pitch_beta = 25
low_speed_theory_limit = 77.1402982083445
prop_sync_available = 0
prop_deice_available = 1
prop_feathering_available = 0
prop_auto_feathering_available = 0
min_rpm_for_feather = 700
beta_feather = 88.5
power_absorbed_cf = 0.9
defeathering_accumulators_available = 0
prop_reverse_available = 0
minimum_on_ground_beta = 1
minimum_reverse_beta = -14
rotation = 1

Gotcha on the displacemen and thanks for the link!
The FAA Type Certified Data Sheet for these engines lists them as:

6 cylinder, - horizontally opposed air cooled direct drive,with fuel injection,
tuned induction, downdraft cooling and bottom side exhaust ports."

http://rgl.faa.gov/Regulatory_and_Guidance_Library%5CrgMakeModel.nsf/0/FFAE5A2BB...


Look forward to your other thoughts and will make some changes when I get home.


Rick


(edit for better link)

So I'm fiddling with the cfg file and reading more about the engine and the 130mm question kept nagging at me.
your explanation of 90x6 = 540 is perfectly reasonable to me. But the data sheet on the AEIO-540 engine is:

"Bore and stroke, in.  -  5.125 X 4.375"     5.125 in = 130.175 mm


Color me puzzled...