Carburator heat in the cessna 152 (MS2020)

[nantelp]

Hi,

I am using PFC quadrant single prop high performance (see picture) 

and I would like to change the middle arm (Prop rpm) to act as  the Carb Heat axis. I have tried to create a user config quadrant in PFCcom64, by defining the Throttle in axis 1, the Carb Heat in axis 3 and the mixture in axis 5.

The axis 3 is not getting recognized. If I try to define it in FSUIPC7 with the axis assignment, I do not find any axis name CarbHeat, not sure what should I use?

I also discovered  that if you assign for example aileron to the first axis and you then want to clear this axis because you made a mistake, you cannot assign the none value anymore. So to clear the user config that you do not want, you need to delete the entry in the PFCcom64.cfg.

Thanks

Pierre

[Pete Dowson]

3 hours ago, nantelp said:

I would like to change the middle arm (Prop rpm) to act as  the Carb Heat axis.

Carb heat is either on or off. Are you seeing an adjustable heating on the aircraft? It's basically just an on/off valve which is opened to send hot air to prevent carb icing, or de-ice it when it gets iced.

So you want a switch, button, or keypress assigned to it, 

Pete

 

[nantelp]

Hi Pete,

In MSFS 2020 for the cessna 152 the heatcab is a axis that goes from cold to 100% see attach picture

So i was trying to configure it as an axis. 

Pierre

[Pete Dowson]

7 hours ago, nantelp said:

So i was trying to configure it as an axis. 

How interesting.

Is it available as an axis in MSFS itself? It has never been so through SimConnect, so if it is in MSFS then it's yet another control they've not yet implemented an interface for. It would need requesting via Zendesk.

Pete

 

 

[nantelp]

Ok I have summitted a Request #68728 Cessna 150 heatcab a axis. With the following text:

In MSFS 2020 for the cessna 152 the heatcab is a axis that goes from cold 0% to 100% see attach picture. Is it available as an axis in MSFS itself? It has never been so through SimConnect, so if it is in MSFS then can you implemented an interface for it? With the interface I would then be able to assign a axis from my quadrant to be use as the heatCab . I can configure the Throttle and the mixture but not the heatCab.

and the picture

Hope they understand? 🙂

[Pete Dowson]

2 hours ago, nantelp said:

In MSFS 2020 for the cessna 152 the heatcab is a axis that goes from cold 0% to 100% see attach picture. Is it available as an axis in MSFS itself? It has never been so through SimConnect

I've been thinking about this since your original message, and two thoughts occurred to me.

On jet aircraft there's an "anti-ice setting, and looking through the list of controls there's one called ANTI ICE SET. Now most "SET" controls are actually usable as axes. So, since the function of Carb Heat it to prevent or remove Ice, I wondered if that might work? Worth a try. Of course, like many other controls, it might not be connected up inside MSFS (yet).

There's also Pitot Heat, but that is to prevent the pitot tube blocking and giving causing wrong airspeed readings, so I doubt that would be used for carb heat.

Pete

 

[nantelp]

Ok I will try that later today

Thanks again

Pierre

[nantelp]

Hi Pete,

When I was creating the user config in the PFC menu see picture. 

 

I discovered  that if you assign for example Throttle2 to the second axis and you then want to clear this axis because you made a mistake and you want it not to be configured. You cannot assign the none value anymore. So to clear the user config axis 2, you need to delete the entry in the PFCcom64.cfg.

I do not think it was the case in version 6?

Pierre

[nantelp]

Hi Pete,

I did the test and when I assign to INTI ICE SET I can push the heat cab in from 100% to 0% but I cannot pull it back to 100%, with my middle blue arm on my quadrant . I need to use my mouse for that. I have include my profile,  PFC and FSUIPC7 ini files for reference. 

Cessna 152.ini

PFCcom64.ini

FSUIPC7.ini

Pierre

[Pete Dowson]

On 10/17/2020 at 3:01 PM, nantelp said:

I discovered  that if you assign for example Throttle2 to the second axis and you then want to clear this axis because you made a mistake and you want it not to be configured. You cannot assign the none value anymore. So to clear the user config axis 2, you need to delete the entry in the PFCcom64.cfg.

I do not think it was the case in version 6?

The only change in my PFC drivers to work with MSFS is to recognise FSUIPC7 so that it links to it correctly. Otherwise it has been unchanged for many years. The main change in the last 5 years was to make a 64-bit version to work with FSUIPC5 on P3D4.

Pete

 

[nantelp]

I just check and it is the same in version 6, not a big deal .

Pierre

[Pete Dowson]

20 hours ago, nantelp said:

I can push the heat cab in from 100% to 0% but I cannot pull it back to 100%

Does Anti Ice Set work for it if you assign in FSUIPC instead? I can test tomorrow just using a button assigned to Anti Ice Set with parameter 16384 and another the same but with parameter 0.  Those are the values I'd expect to produce 100% and 0% respectively. I'm wondering if it might be yet another MSFS bug.

If you enable Axis and Even logging in FSUIPC, does the FSUIPC log show the anti-ice events at all?  You might also check via PFCcom64 logging.

Just for my education, please tell me, when would you use partial carb heat, eg 50%? What would be the purpose? it seems to me you either want the hot air on the Carb to prevent or remove ice, or off because it isn't needed. I always thought it would just be an on/off setting.

Pete

 

[nantelp]

2 hours ago, Pete Dowson said:

Does Anti Ice Set work for it if you assign in FSUIPC instead

That what I did, I assigned the set using the axis in FSUIPC. The axis doesn't show in the even log 

FSUIPC7.log

Quote

Just for my education, please tell me, when would you use partial carb heat, eg 50%? What would be the purpose? it seems to me you either want the hot air on the Carb to prevent or remove ice, or off because it isn't needed. I always thought it would just be an on/off setting.

From my understanding the Cessna 152 take is cab air from the front vent (filtered) and when you engage the cab heat  it then takes the air from the manifold (not clean air, un-filtered) but hot. So at 50% you are getting 1/2 clean cold air and 1/2 dirty hot air. So if you need a little bit of hot air to manage ice building in the cab, you use a mix of air input, which is supposedly better for the motor.

Pierre 

[Thomas Richter]

Hi,

MSFS doesn't support for CarbHeat any other than ON or OFF (1 or 0). This is true even in direct setup in MSFS when assigning an axis or button or key. It can be seen that the engine reacts to any setting correct 0 to 100% but those values cannot be set or read via SimConnect.

When assigning an axis in MSFS or as well in FSUIPC7 it works correct to switch CarHeat ON or OFF, axis >half way up or < halfway down. Any value than 100% reflects to CarbHeat=OFF.

Carb air is always filtered, cold air is direct airflow but hot air is re-directed air flowing over the exhaust pipe surface to heat up before entering the carb.

Thomas

[Pete Dowson]

3 hours ago, nantelp said:

That what I did, I assigned the set using the axis in FSUIPC.

No, I did actually mean assign to buttons to send values 0 and 16383, explicitly, in case the axis wasn't getting through with such a range. A button for 0% and another for 100% would show whether the action you couldn't make work with an axis assignment was only because of incorrect values.

Anyway, I see Thomas has already done the testing in MSFS and reported the results for you. (Thanks Thomas!).

Pete

 

[nantelp]

This is too bad, for the Cessna 152 it is important to have the axis to work. I when back to my owner manual and they explain why they do not recommend to

 flying with 100% carb heat. 

17 hours ago, Thomas Richter said:

Carb air is always filtered, cold air is direct airflow but hot air is re-directed air flowing over the exhaust pipe surface to heat up before entering the carb.

Thomas for your info, this is from the owners manual:

CESSNA SECTION 4
MODEL 152 NORMAL PROCEDURES
The carburetor heat control knob should be pushed full in during all
ground operations unless heat is absolutely necessary. When the knob is
pulled out to the heat position, air entering the engine is not filtered.

see document:

Cessna 152 owners manual page 50.pdf

Pete,

I do have a icing push bottom on my Cirrus II and it does work as an on and off. I was just trying to get the blue arm of my quadrant to work. It is important for that plane to be able to increase or decrease the Carb Heat input. 

Thanks

Pierre

[John Dowson]

It may be possible in an actual Cessna, but as Thomas has stated: MSFS doesn't support for CarbHeat any other than ON or OFF (1 or 0).

To support a carb heat axis or values other than on/off, MSFS need to implement this. You therefore need to raise a new feature request with Asobo/MSFS.

 

[nantelp]

Thanks Pete,

Something I do not understand is, I can use the mouse to pull and push the cab heat. The mouse doesn't use an axis? 

Pierre

[John Dowson]

1 minute ago, nantelp said:

Something I do not understand is, I can use the mouse to pull and push the cab heat. The mouse doesn't use an axis? 

That's just the graphics/visuals, not the model. I suspect that the model value would still be 0 (as Thomas says) when the graphics show < 100%.
Do you notice any affect when you have, say, 50% carb heat? And if so, is this any different from 100%?

[nantelp]

Good point John,

If it is well simulated I should see a impact on the power with 100%, according to the manual I should loss about 10% . I will test this on my next flight. 

Pierre

[John Dowson]

1 minute ago, nantelp said:

If it is well simulated I should see a impact on the power with 100%, according to the manual I should loss about 10% . I will test this on my next flight. 

But also test with 50% or 75%. If this is graphics only and not affecting the model, then you should either see no change (i.e. <100% = 0) as we suspect, or (maybe) still see the same as if it was 100%.

[nantelp]

Hi,

I been flying for about 7 hr in -25C and I cannot reproduce a carburetor icing event. The only thing I see is, when I put the Cab Heat at 100%, the RPM goes down about 10000. If I put the Cab Heat at 50% the reduction seem less. But I cannot guarantee that I have a icing issue.

But on thing I learned, is that this software need to mature, so I am going back to P3D v5 until next year. None of the default aircraft are even close to reality. 

Pierre 

[CharlySim]

Hi Pierre,

Due to Venturi effect and fuel vaporisation carb icing can occur even at +2O°C depending on the relative humidity, no need for the outside temperature to be under 0°C.

On C150, 152, ... During the run up checks when the carb heater is On then hot air arrives into the carburetor which causes a drop of rpm (hot air is less dense than cold air) , this shows that the carb heater device works properly. In a real C150 the carb heater is always used like an on/off switch even if it is wired controlled

Does it help you ?

Edited October 30, 2020 by CharlySim

[nantelp]

Yes thanks,

With the last patch they did a lot of work on the C150, so I will see if I can now assign my axis, using the new SDK. If not, well to bad. 

Not a big problem

Pierre

 

[mryan75]

Hi all,

I know I have an account here, but I can't get the password reset email.

Anyway, has anyone figured this out? To clear a few things up: you can get carb ice from around 20 degrees C down to -5 degrees C. Flying around at -20 degrees C will not produce carb ice. In real aircraft it is an axis. If you have a carb temperature gauge you would use it to bring the carb temp above freezing. If you don't have a carb ice gauge (and most small piston singles don't), you would put it full on if you suspect carb ice.

Either way, I'd like to map the carb ice setting to an unused axis on my HC Bravo just because it's more realistic to have it as an axis, even if I only really get full on or full off. That's fine, I just do want an axis. Though maybe one has come to being for carb ice in MSFS since this thread was last active.

I don't see any way to set carb ice at all in FSUIPC7. Any help would be appreciated.