[XPLANE] DC-6 Supercharger inquiries

[Davidrebolton 42]

Can we get an official update from you guys at PMDG on how the DC-6's update to XP11 is coming along? :) 

With thanks 

[CrashTronic 3]

Hi Dave,

PMDG appear to be focused on the completion of the FSX/P3D release cycle. @rsrandazzo said the PMDG team would evaluate the next steps after they complete the work. Except for a quick code update to get the rudder to move in the correct direction, it is very flyable at low blower settings.

I know this isn't much to go on but PMDG will update when they have more specific information to contribute.

Hope this helps,

 

Mike

[Pilot53 543]

BMEP, MP and Fuel Flow are not just broken in xp11, but in xp10 also.  None of the number even come close to the tables provided, or make any sense at all, while in the p3d version the actual values match the tables much better and make much more sense.  Im hoping they will update xp11, but even the xp10 version is still incomplete in my mind.

[scandinavian13 5,192]

6 minutes ago, Pilot53 said:

BMEP, MP and Fuel Flow are not just broken in xp11, but in xp10 also.  None of the number even come close to the tables provided, or make any sense at all, while in the p3d version the actual values match the tables much better and make much more sense.  Im hoping they will update xp11, but even the xp10 version is still incomplete in my mind.

This is not true. At least not on my system. Given the rampant third party over-reliance on scripting in XPL, I'm willing to bet that it's some other add-on interacting and causing the issue you're seeing.

[Pilot53 543]

8 hours ago, scandinavian13 said:

This is not true. At least not on my system. Given the rampant third party over-reliance on scripting in XPL, I'm willing to bet that it's some other add-on interacting and causing the issue you're seeing.

Ive tried even with stock xplane, and comparing to videos of others on youtube they are experience the same behavior, but I dont think they realize it because very few seem to actually fly it by the book.  Fuel flow is too low during climb and takeoff, and manifold pressure is always too high and bmep doesnt match the books at all.  If you compare the xplane and p3d versions side by side you will see that the engine readings for identical regimes of flight are quite different between the two versions, but the p3d version matches the books much more closely.

[CrashTronic 3]

@Pilot53 can you provide screenshots demonstrating this behavior? I'm on a work trip right now so i don't have access to xplane. Please perform any testing at standard atmospheric conditions. Thanks!

 

Thanks!

Edited September 3, 2017 by CrashTronic
test parameters

[CrashTronic 3]

@deimos256 Thanks, I adjusted my values as well for SFC. I also noticed the mixture control doesn't work in XP11 either, I'm currently investigating why that might be.

Current numbers:

High

Max: 0.684

half: 0.633

 

Low

Max: 0.715

half: 0.553

I tried turning off the FADEC settings in plane maker and in the sim but the programming in the DC-6 still sets the mixture full rich regardless of where the handle is set.

Interesting sidenote: the prop is super sonic at the tips at all times, not due to anything PMDG did but because of the diameter of the prop spinning at higher than 1651 rpm.

 

I tried last night to fly the plane in FSX:SE and I see what many people say about airplanes feeling like they are on rails. I get a much more fluid sensation from X-Plane

 

[CrashTronic 3]

As expected it's more complicated than it appears. mixtures are auto adjusting as the name implies. Further testing in progress.

Edit: nope im just a doofus. It works fine.

[CrashTronic 3]

I have resolved the fuel flow issues in XPLANE 11

Open up the plane maker, go to the engines screen, go to the SFC tab. Set the following values

Altitude: 10,000ft

High Alt Full Power: 0.841666667
Low Alt Full Power: 0.762500000
High Alt Half Power: 0.452500000
Low Alt Half power: 0.452500000

Follow this guide if you need: http://developer.x-plane.com/manuals/planemaker/index.html#creatingtheengines

@Pilot53 @deimos256

[CrashTronic 3]

Or you can open the DC-6 ACF file and remove/replace the following specific fuel consumption

P acf/_SFC_alt_hi_PRP 10000.0
P acf/_SFC_alt_lo_JET 0.0
P acf/_SFC_alt_lo_PRP 0.0
P acf/_SFC_full_hi_JET 0.0
P acf/_SFC_full_hi_PRP 0.842
P acf/_SFC_full_lo_JET 0.0
P acf/_SFC_full_lo_PRP 0.763
P acf/_SFC_half_hi_JET 0.0
P acf/_SFC_half_hi_PRP 0.453
P acf/_SFC_half_lo_JET 0.0
P acf/_SFC_half_lo_PRP 0.453

This change doesn't address the high blower setting issues when switching from low to high.

[deimos256 2]

I'll give those numbers a try when I get some time. 

[CrashTronic 3]

Just a quick update for the SFC

The Full power High and low SFC should be 0.962. The low numbers stay the same.

This should give much better fuel flows.

Thanks

[CrashTronic 3]

X-Plane 11.10 beta

With the addition of the new aerodynamics and minor changes to the piston code I have reformulated the SFC for the DC-6.

Things of note:

1. The specific fuel consumption values match in sim to POH values at 1200 bhp and 2400 bhp
2. The actual x-plane sfc model appears to follow a (c+x^n)/x rational function where X is power and Y is SFC, however at the power levels concerned a linear approximation is quite adequate for the 1/2 power to full power range with SFC deviating from expected values at lower power values.
3. The fuel flows per engine do not match poh values and deviate from poh as follows (low blower only, auto-rich)
   1. 1800BHP (METO)  -140pph
   2. 1500BHP (Climb)   -150pph
   3. 1400BHP (Climb)   -150pph
   4. 1200BHP (Cruise)  +65pph
   5. 1100BHP (Cruise)  +87pph
4. ACF SFC set values
   1. P acf/_SFC_half_lo_PRP 0.3982
   2. P acf/_SFC_half_hi_PRP 0.3982
   3. P acf/_SFC_full_lo_PRP 0.70225
   4. P acf/_SFC_full_hi_PRP 0.70225
5. X-Plane SFC observed / POH
   1. 1200BHP (Half) - 0.487 (597pph)   / 0.487
   2. 2400BHP (Full) - 0.861 (2067pph) / 0.857
6. I have not tuned the high altitude (hi) SFC values or the Auto-lean.

Edited October 19, 2017 by CrashTronic

[CrashTronic 3]

On 10/18/2017 at 7:23 PM, CrashTronic said:

X-Plane 11.10 beta

With the addition of the new aerodynamics and minor changes to the piston code I have reformulated the SFC for the DC-6.

Things of note:

1. The specific fuel consumption values match in sim to POH values at 1200 bhp and 2400 bhp
2. The actual x-plane sfc model appears to follow a (c+x^n)/x rational function where X is power and Y is SFC, however at the power levels concerned a linear approximation is quite adequate for the 1/2 power to full power range with SFC deviating from expected values at lower power values.
3. The fuel flows per engine do not match poh values and deviate from poh as follows (low blower only, auto-rich)
   1. 1800BHP (METO)  -140pph
   2. 1500BHP (Climb)   -150pph
   3. 1400BHP (Climb)   -150pph
   4. 1200BHP (Cruise)  +65pph
   5. 1100BHP (Cruise)  +87pph
4. ACF SFC set values
   1. P acf/_SFC_half_lo_PRP 0.3982
   2. P acf/_SFC_half_hi_PRP 0.2992
   3. P acf/_SFC_full_lo_PRP 0.70225
   4. P acf/_SFC_full_hi_PRP 0.66325
5. X-Plane SFC observed / POH
   1. 1200BHP (Half) - 0.487 (597pph)   / 0.487
   2. 2400BHP (Full) - 0.861 (2067pph) / 0.857

New Changes to the high alt values. Tested at 19000 low blower auto lean for cruise

[deimos256 2]

These are pretty good numbers.  I'll be sticking with them for the foreseeable future.