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P3D v4 Pratt & Whitney R-985 Oil Usage

tgycgijoes

tgycgijoes

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I created this gauge to represent Oil Quantity check in the preflight for the Spartan Executive modifying with permission Bob Kellogg's Fuel Quantity Gauge. I couldn't get it to work and neither could Bob this weekend. It is supposed to show full quiantity and then with colored bars reflect oil consumption by the R-985 Pratt & Whitney Radial Engine. If it can be made to work it can also be added to any other aircraft in P3D that uses this engine like the DHC-2 Beaver and the Gee Bee racer if someone desires. Thank you in advance for your help, we are stumped.
 

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Checking back her after five days, I see that 58 of you have looked at this but I have not had any replies. The XML variable IS in the SDK so it must be possible to do this I assume. I just don't know how, and Bob Kellogg said he couldn't figure it out either. Tom Gibson created these for the four engines of his DC-6. I am not savvy enough though to modify them to work with a single P&W R-985.
 
The SDK indicates it's a percentage and not an actual amount. Has anyone tested this var in 64-bit? Also, this var doesn't exist: ENG1_OIL_CONS_NORM.
 
For the Stearman and for MSFS, I had a XML script to compute the consumption of oil in fonction of some parameters: rpms, time of flight, etc...
Theses datas can be read in the technical manuels so for P3D i could be possible to do the same with XML.
 
To the best of my knowledge, no FS-based sim has ever provided a variable that gives you oil burn per engine. I can't speak for MSFS202x but neither the aircraft.cfg file nor the aircraft.air file in the other sims ever provided a method to define oil burn. If you can't get the existsing gauge to work, the best option is to start again from scratch.

As Lagaffe says, you have to compute your own oil consumption to reduce the percentage shown by the sim during flight. I did this for the Wright R-2600 series where oIl burn information was taken from the relevant Curtiss-Wright manuals. As they only give burn by volume, that had to be converted into percentage burn. The resulting percentage reduction was set on the sim using SimConnect. However, this requires the use of a C/C++ gauge.

The better alternative is to completely ignore the percentage values provided by the sim and use your own variable to track oil use depending on the engine power output. This gives you the ability to calculate oil burn either by percentage or by volume, depending on your preference. It also means that the calculation should be (relatively) easy in XML as you have complete control over the maths vs. flight parameters. The very simplest way to do it is to get the amount of oil burned vs rpm specified by the engine manufacturer; for example, the R-2600-11 has the following specifications:

Max allowable oil consumption at normal rated power: 17qts/hr
Normal rated power: 2300rpm

Max allowable oil consumption at maximum cruising: 13qts/hr
Max cruise: 2050rpm

Treat it as a linear slope, so if the RPM is set to 2175 then the engine will burn 3.75qts after 15mins, 7.5qts after 30mins and 15qts every hour. Note that this is maximum allowed oil consumption, but I've never found an engine manual that gives minimum oil consumption. I'd reduce the maximum figure by no more than 10% if you want a 'good' engine. Or randomise it on a per-flight basis.

[Edit] For anyone else: Pratt & Whitney R-985 Operating Manual.
 
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https://en.wikipedia.org/wiki/Wright_R-2600_Twin_Cyclone

Yikes... that is a lot of oil per hour at max RPM's.

I'm guessing the Radial Cylinder Head temps and Cowl Flap use should limit being able to achieve / maintain that.

Now I know why we always saw so much exhaust smoke contrail Effects in detailed legacy FS2Kx user aircraft.


One might wonder how many less bombs WWII aircraft carried due to oil weight / consumption on long flights.


I recall a sophisticated gauge used in the Grumman Widgeon Twin Wasp Radial... I was always killing the engines.

https://library.avsim.net/search/basic/root/Grumman_Widgeon_VC_radial_engines.zip

https://library.avsim.net/search/basic/root/Grumman_G44_Widgeon_20_Update_Corrected.zip


I wonder if that detail was used in FS2Kx' R-985 for Beaver, Stearman, Grumman Goose, and Spartan engines ? :scratchch

https://en.wikipedia.org/wiki/Pratt_&_Whitney_R-985_Wasp_Junior

https://www.google.com/search?q=FSX+gauge+R-985+Pratt+&+Whitney+Radial+Engine+Oil+quantity&sca_esv=d7358c9ad4b11281&biw=1088&bih=504&ei=XZ2QaajSMrTaptQPrPreyQU&ved=0ahUKEwjo9OOprtmSAxU0rYkEHSy9N1kQ4dUDCBM&oq=FSX+gauge+R-985+Pratt+&+Whitney+Radial+Engine+Oil+quantity&gs_lp=Egxnd3Mtd2l6LXNlcnAiOkZTWCBnYXVnZSBSLTk4NSBQcmF0dCAmIFdoaXRuZXkgUmFkaWFsIEVuZ2luZSBPaWwgcXVhbnRpdHkyBRAAGO8FMgUQABjvBTIFEAAY7wUyBRAAGO8FSMddUPIxWIpAcAJ4AJABAJgB8AGgAeIHqgEFMC41LjG4AQzIAQD4AQGYAgigAoIJwgIIEAAYsAMY7wWYAwCIBgGQBgSSBwUyLjUuMaAH8hWyBwUwLjUuMbgH3gjCBwcyLTEuNi4xyAdpgAgA&sclient=gws-wiz-serp


"In Flight Simulator X (FSX), specifically when flying add-on aircraft equipped with the Pratt & Whitney R-985 Wasp Junior (such as the DHC-2 Beaver or Spartan Executive), the oil quantity gauge typically indicates the remaining oil in the tank, often measured in gallons or a relative "Full to Empty" scale, rather than quart."


https://www.google.com/search?q=FSX+R-985+Pratt+&+Whitney+Radial+Engine+Oil+quantity&sca_esv=d7358c9ad4b11281&ei=uJyQaeiZMfqHptQPqcTb-QM&biw=1088&bih=504&ved=0ahUKEwjo1YvbrdmSAxX6g4kEHSniNj8Q4dUDCBM&uact=5&oq=FSX+R-985+Pratt+&+Whitney+Radial+Engine+Oil+quantity&gs_lp=Egxnd3Mtd2l6LXNlcnAaAhgCIjRGU1ggUi05ODUgUHJhdHQgJiBXaGl0bmV5IFJhZGlhbCBFbmdpbmUgT2lsIHF1YW50aXR5MgUQIRigATIFECEYoAEyBRAhGKABMgUQIRigATIFECEYoAFIlM0BUIwJWIrJAXABeAGQAQCYAa0BoAGAEaoBBDQuMTW4AQPIAQD4AQL4AQGYAhSgAooUwgIKEAAYsAMY1gQYR8ICDRAAGLADGNYEGEcYiwPCAgUQIRirAsICBRAAGO8FwgIIEAAYgAQYogSYAwCIBgGQBgiSBwQxLjE5oAfGXLIHBDAuMTm4B_UTwgcGMi0zLjE3yAfvAYAIAA&sclient=gws-wiz-serp

https://library.avsim.net/search/basic/root/Spartan_Executive.zip

GaryGB
 
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Thank you for all the comments. The SDK DOES have a variable for OIL QUANTITY and Tom Gibson separated a separate guage for Oil Consumed (used).
 
ENG [COLOR=#111111]OIL[/COLOR] [COLOR=#111111]QUANTITY[/COLOR]:indexThe indexed engine (see note) oil quantity as a percentage of full capacity.
Percent Over 100

It's useless because as explained above, it does nothing unless you tell it to.

The [generalenginedata] section has a default_oil_leak_rate which, if triggered by a malfunction, will affect the oil quantity but that's it. No amount of running the engine until it runs out of fuel is going to automatically change the oil quantity otherwise. As for Tom's gauge: calling @tgibson
 
Thank you all for this. There are some things in real life that the flight simulators just do not do. Onto something else.
 
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