Please explain to me the rationale for opening cowl vents ...halfway and all the way! The Duke has this functionality, and I need to know when, where, why I should use the cowl vent lever. I did notice that when flying the Duke near Binghamton, N.Y. the other day with real weather (ASA) snow, that my engine died at 5000 ft. and my cowl vents were closed. When I opened the cowl vents halfway, I re-flew the short flight (Wilkes-Barre to Binghamton) and the flight ended in success.Stan

One possibility is to control engine temps, especially on air cooled engines.

Please explain to me the rationale for opening cowl vents ...halfway and all the way! The Duke has this functionality, and I need to know when, where, why I should use the cowl vent lever. I did notice that when flying the Duke near Binghamton, N.Y. the other day with real weather (ASA) snow, that my engine died at 5000 ft. and my cowl vents were closed. When I opened the cowl vents halfway, I re-flew the short flight (Wilkes-Barre to Binghamton) and the flight ended in success.Stan

Hi Stan,Cowl flaps when open help cool the engine. Usually they are open for takeoff and taxi-you generally close them after you level out in cruise, and reopen them after landing or on a missed approach/go around for climb.What you really want to do is monitor your engine temps and open/close them based on recommended engine temperature e.g. sometime in the summer when hot we will leave ours open even at cruise to keep the engine at the recommended temperature.

Please explain to me the rationale for opening cowl vents ...halfway and all the way! The Duke has this functionality, and I need to know when, where, why I should use the cowl vent lever. I did notice that when flying the Duke near Binghamton, N.Y. the other day with real weather (ASA) snow, that my engine died at 5000 ft. and my cowl vents were closed. When I opened the cowl vents halfway, I re-flew the short flight (Wilkes-Barre to Binghamton) and the flight ended in success.Stan

Manual. Page 28. Explains all. Read the rest of it too, saves loads of questions and explains the level of complexity you have bought into.

Thanks for the explanation, guys. I think my fuel flow went down because of not having carb heat on.....does that sound logical?Stan

Thanks for the explanation, guys. I think my fuel flow went down because of not having carb heat on.....does that sound logical?Stan

Considering it is a fuel injected engine it should not be a factor-other than the well known fs carb heat for every engine bug which means it could be a factor... :(

Yes , and that is one thing that isn't covered in the manual... ANY manual. It's another well-known FSX bug.A blocked carb obviously has the effect of reducing fuel flow, but equally the wat the sim works too high CHT or EGT/** can also restrict flow - it's Flight Sims simplistic way of telling you something is wrong.Only other factor that causes fuel flow to decline is incorrect mixture. Are you leaning per the manual?

The Duke uses the carb heat (CH) control to (more than somewhat incorrectly) model the fuel tank vent de-ice control. Check the switches on the lower left of your panel (labeled fuel vents or somesuch) when you tap the "H" key (carb de-ice) on the keyboard. The Duke, as stated above, is fuel injected and thus does not need carb de-ice. Whiners will complain that the carb heat is used incorrectly in the Duke and they are right in some aspects. But using the CH to begin to model things like fuel vent de-ice, having cowl flaps that need to be used properly controlled and cyl head temps that need to be properly monitored moves the Duke far ahead of the many "run of the mill" sims we use today. I've flown the Duke almost exclusively since the day it was first offered, it's the best light twin on the market today, IM (not so) HO.

This information was what I was looking for. I haven't had a GA plane (or any other for that matter) suddenly decrease the fuel flow. I need to look more closely at the manual. I was able to safely land by reducing altitude to around 3000 ft. when the fuel flow went back up to normal.Stan

The Duke uses the carb heat (CH) control to (more than somewhat incorrectly) model the fuel tank vent de-ice control. Check the switches on the lower left of your panel (labeled fuel vents or somesuch) when you tap the "H" key (carb de-ice) on the keyboard. The Duke, as stated above, is fuel injected and thus does not need carb de-ice. Whiners will complain that the carb heat is used incorrectly in the Duke and they are right in some aspects. But using the CH to begin to model things like fuel vent de-ice, having cowl flaps that need to be used properly controlled and cyl head temps that need to be properly monitored moves the Duke far ahead of the many "run of the mill" sims we use today. I've flown the Duke almost exclusively since the day it was first offered, it's the best light twin on the market today, IM (not so) HO.

I think that control was used as a workaround for the lack of channels to address all the engine requirements on the Duke. Sometimes we have to find alternative ways. Good spot though!Kind Regards,Rob Young - RealAir Simulations

Oh yes!! I knew that it was a work around and (again IMHO) a clever one too. I really really like the Duke. I am not exaggerating when I say I have flown nothing else since it was released. I have nearly 100 hours on the Hobbs Meter now. These are all real time hours. While I may not sit in front of the sim 100% of the time, I don't use any time compression. 100 hours means 100 hours. It is my sim of choice.

The Duke uses the carb heat (CH) control to (more than somewhat incorrectly) model the fuel tank vent de-ice control. Check the switches on the lower left of your panel (labeled fuel vents or somesuch) when you tap the "H" key (carb de-ice) on the keyboard. The Duke, as stated above, is fuel injected and thus does not need carb de-ice. Whiners will complain that the carb heat is used incorrectly in the Duke and they are right in some aspects. But using the CH to begin to model things like fuel vent de-ice, having cowl flaps that need to be used properly controlled and cyl head temps that need to be properly monitored moves the Duke far ahead of the many "run of the mill" sims we use today. I've flown the Duke almost exclusively since the day it was first offered, it's the best light twin on the market today, IM (not so) HO.

This solution WORKED for me. I clicked the switches on the lower left panel and turned on the fuel vents. All is well now with the Duke.Stan

To add a little more realism I use the fuel vent heaters while climbing or cruising when ice might form (whenever you use the pitot heat). Because Real Air is using what is normally thought of as carb heat to simulate fuel vent heaters, the vents will never ice up at those times but it's fun to do anyway (am I too easily amused?). You will need to use the vent heaters when descending under trailing throttle however to maintain proper MAP. Like I said before, it's not 100% accurate by any means, but it's better than what anyone else has done. Congrats to Real Air.