Carb Heat Command

[chumley]

I read somewhere (can't for the life of me remember where) that to ensure Carb Heat is always switched on to circumvent the P3D fault it can be linked to the raising of the undercarriage.

I currently have a lever (axis) on my TQ6 controller set to raise and lower the gear.

Is it possible to link the Carb Heat function to this action on my controller and if so could you point me in the direction of how it is set up

Thanks

[Pete Dowson]

I’m not at home at present but will send methods when I return, but meanwhile can you tell me what “the P3D fault” is? You seem to be assuming it is general knowledge and is not going to be corrected.

It would be helpful if you could find where you read this advice, as it seems very strange to me.

Pete

 

[ThomasAH]

It is not specific to P3D, but already present in FSX, too.

Some links:

https://www.avsim.com/forums/topic/375838-the-carb-heat-bug-for-fuel-injected-engine-fixed-by-payware-aircrafts/

http://www.prepar3d.com/forum/viewtopic.php?t=12379

https://www.avsim.com/forums/topic/364421-icing-or-why-engine-slow-down/#comment-2282713

https://www.avsim.com/forums/topic/408841-question-to-the-carenado-c337-owners/#comment-2676149

and various others. I must admit that it took me some years to find out about this bug, too :)

[Pete Dowson]

2 hours ago, ThomasAH said:

It is not specific to P3D, but already present in FSX

Thanks for the links. This, from one of them, seems to contradict the idea that it is a "bug", and it is from a contibutor whose opinions I value:

Actually, it is not and never has been a 'bug' per se. Even fuel injected engines require an air source, and unless you have some way to heat the air intake, you can and will have ice formation.

I'm not sure why you'd want the switch operated by gear up, but if you'd programmed this in the FSUIPC axis assignments using the range part on the right, why not simply reserve a small part of the area representing the movement towards "gear up" as an other zone which is assigned to the so-called Carb Heat switch?  (i.e. have three zones instead of one or two).

The control assigned to the 'H' key by default is actually known internally in FSX and P3D as "Anti ice toggle" (applicable to jets as well as props, like "Pitot heat toggle", which is Shift+H) and that's what you need to assign to. As it's a toggle you'd need that range applicable to both up and down passage through it.

Pete

 

[ThomasAH]

4 hours ago, Pete Dowson said:

Thanks for the links. This, from one of them, seems to contradict the idea that it is a "bug", and it is from a contibutor whose opinions I value:

Actually, it is not and never has been a 'bug' per se. Even fuel injected engines require an air source, and unless you have some way to heat the air intake, you can and will have ice formation.

While this is mostly true, this type of icing happens more easily on fuel injected engines in FSX than other sources suggest, e.g. https://www.pprune.org/archive/index.php/t-334977.html

(this mentions icing in air intakes, too, so this matches what N4GIX wrote in the linked P3D ticket)

 

I have seen this problem (bug or not) very often in FSX, and with both engines of e.g. a Carenado 337H always losing power at exactly the same time.

[chumley]

17 hours ago, Pete Dowson said:

Thanks for the links. This, from one of them, seems to contradict the idea that it is a "bug", and it is from a contibutor whose opinions I value:

Actually, it is not and never has been a 'bug' per se. Even fuel injected engines require an air source, and unless you have some way to heat the air intake, you can and will have ice formation.

I'm not sure why you'd want the switch operated by gear up, but if you'd programmed this in the FSUIPC axis assignments using the range part on the right, why not simply reserve a small part of the area representing the movement towards "gear up" as an other zone which is assigned to the so-called Carb Heat switch?  (i.e. have three zones instead of one or two).

The control assigned to the 'H' key by default is actually known internally in FSX and P3D as "Anti ice toggle" (applicable to jets as well as props, like "Pitot heat toggle", which is Shift+H) and that's what you need to assign to. As it's a toggle you'd need that range applicable to both up and down passage through it.

Pete

 

Thanks for the advice.

The reason I thought about the 'gear up' link was that the icing event and subsequent power loss happens at varying altitudes depending on the temperatures and ca be a problem when traversing mountains as I do in NZ given the aircraft loses power and descends eventually until it reaches a point at which icing stops then the engine roars to life and climbs again sadly too late sometimes.

I figured that if I turn on Carb Heat when the gear goes up and off when it comes down that would stop me forgetting.

[Pete Dowson]

16 minutes ago, chumley said:

I figured that if I turn on Carb Heat when the gear goes up and off when it comes down that would stop me forgetting.

Okay. Or you could od as real pilots and have a Check List, of course. ;-)

I need one with my 737, otherwise there's always something I've forgotten!

Pete

 

[ThomasAH]

I have pressing H on my checklist, too ... together with things like which program to start first or which USB cable goes where :)