The A2A Simulations Community

Hi everyone,

I was flying in -22c and when at 8,000 - 10,000 I turned the filter off as the crew stated, however the problem was because the air is so cold outside I get a warning the carb heat is TOO low so I turn the filter back on to get warmer air from inside the wing but then I get a crew warning saying at that height I sohuld have filter off

So I turn filter on and off and on and off etc

What should I be doing ? Is there a way to get carb heat up when the air is cold outside and you are using ram air.

*I am using the copilots to do RPM/Cowl/Intercoolers
*I cruise with the turn control (sorry I forgot the name) on 4.0 or 5.0

Pretty sure I've missed something to help stop the carb heat going down, tends to be Engine 1 and 2 that falls rather than 3 and 4

Thoughts ?
Thanks in advance everyone.

Increase the turbos in that condition. Run the turbos up to 8.

Paul

Gypsy Baron wrote:Increase the turbos in that condition. Run the turbos up to 8.

Paul

Really ?? at 8 ? isn't that too high and straining the engine ??

More turbo and less throttle to maintain the desired manifold pressure

Styggron wrote:

Gypsy Baron wrote:Increase the turbos in that condition. Run the turbos up to 8.

Paul

Really ?? at 8 ? isn't that too high and straining the engine ??

Not at all. I run my turbos at 8 almost all the time. I have over 1650 hours on my
engines and they are in excellent shape.

The only time I run the turbos below "8" is when I am flying formation and want to use
a click or two on the turbos to adjust my speed slightly.

You definitely want to run the turbos up from your cruise setting when descending
to keep the carb temps from getting too low.

Paul

Gypsy Baron wrote:

Styggron wrote:

Gypsy Baron wrote:Increase the turbos in that condition. Run the turbos up to 8.

Paul

Really ?? at 8 ? isn't that too high and straining the engine ??

Not at all. I run my turbos at 8 almost all the time. I have over 1650 hours on my
engines and they are in excellent shape.

The only time I run the turbos below "8" is when I am flying formation and want to use
a click or two on the turbos to adjust my speed slightly.

You definitely want to run the turbos up from your cruise setting when descending
to keep the carb temps from getting too low.

Paul

Thank you. Ok understood. But the pilot notes and manual say 4-5 so I'm not sure there. Anyway I shall do as you say. I ADORE flying this plane it is fantastic.

I found mine drifts to the right a tad so aileron trim and rudder trim does the trick both at -20% though I thught it was the right fuel tanks but it was only different by around 9 gallons (I wish it was metric!) so that would have been it I think.

thank you again.

I fly in the Northeast, so we have a history of long cold winters. After studying WWII B-17 training films, and doing a little experimentation, I've found that the following works best for me:

Warm up the engines on the ground, I mean really warm. Idle 10-15 min until your cylinder head temp is over 180 and Oil temp is over 50.

Make sure your carb filters are on and have your turbo set to about 5, this will heat up your carbs and stop them from icing over.

Before takeoff (during run up) have the turbo set to 8, intercoolers to warm, and if runway length permits take off at a lower power setting MAP 38". Use 1/3 flaps if needed.

If your carbs are warmed up on the ground enough, I've found that there is only a small drop in temp when you turn the filters off. Make sure you're also reducing MAP to about 34" and keep the turbos at 8. Those settings have kept my carb temp in the mid 20's while OAT was -45.

Hope this helps,
-Scott

FireRescue85 wrote:I fly in the Northeast, so we have a history of long cold winters. After studying WWII B-17 training films, and doing a little experimentation, I've found that the following works best for me:

Warm up the engines on the ground, I mean really warm. Idle 10-15 min until your cylinder head temp is over 180 and Oil temp is over 50.

Make sure your carb filters are on and have your turbo set to about 5, this will heat up your carbs and stop them from icing over.

Before takeoff (during run up) have the turbo set to 8, intercoolers to warm, and if runway length permits take off at a lower power setting MAP 38". Use 1/3 flaps if needed.

If your carbs are warmed up on the ground enough, I've found that there is only a small drop in temp when you turn the filters off. Make sure you're also reducing MAP to about 34" and keep the turbos at 8. Those settings have kept my carb temp in the mid 20's while OAT was -45.

Hope this helps,
-Scott

Hello FireRescue85
Realy ? 10-15min real time waiting for warm ups ?

Filters have to come off when above 10,000 though this was the problem I was having.
I shall heed your advice and try what you say.

Thank you

Yup, it can take a while but it's worth it to avoid damaging the engines. Granted, this is from going from the cold start scenario where your oil temp is well below zero. If you push your engines too hard with cold oil you'll start blowing oil lines due to the extremely high pressure (learned that the hard way before lol).

And like I said, I haven't had any problems keeping the carbs warm with the filters off above 10k as long as they have been prewarmed, intercoolers are to hot, and manifold is set to about 33" with the turbos at 8. It seems like a high turbo setting, but in the extreme temperature it's needed to keep them from freezing. If you have your copilot handle intercoolers, sit in his seat and watch what happens once you get to altitude: He'll keep the intercoolers at 0% until carb temps start to get high, and then he'll crack them to 1%. The air is so cold (sometimes -45C) that the carb temp drops down to 12C within seconds. In short, let him handle the intercoolers to decrease the chance of one accidentally icing up.

Honestly, I watched this YouTube channel to learn how to properly run the engines and deal with emergencies. The channel has a full playlist of actual Department of Army B-17 training films.

https://www.youtube.com/watch?v=mzcP1IYHJmc

FireRescue85 wrote:Yup, it can take a while but it's worth it to avoid damaging the engines. Granted, this is from going from the cold start scenario where your oil temp is well below zero. If you push your engines too hard with cold oil you'll start blowing oil lines due to the extremely high pressure (learned that the hard way before lol).

And like I said, I haven't had any problems keeping the carbs warm with the filters off above 10k as long as they have been prewarmed, intercoolers are to hot, and manifold is set to about 33" with the turbos at 8. It seems like a high turbo setting, but in the extreme temperature it's needed to keep them from freezing. If you have your copilot handle intercoolers, sit in his seat and watch what happens once you get to altitude: He'll keep the intercoolers at 0% until carb temps start to get high, and then he'll crack them to 1%. The air is so cold (sometimes -45C) that the carb temp drops down to 12C within seconds. In short, let him handle the intercoolers to decrease the chance of one accidentally icing up.

Honestly, I watched this YouTube channel to learn how to properly run the engines and deal with emergencies. The channel has a full playlist of actual Department of Army B-17 training films.

https://www.youtube.com/watch?v=mzcP1IYHJmc

Thank you for that. Fantastic set of vintage videos there.
Sounds like I *want* to push the engines hard to cause failures so I can see how it all works. This is a sim after all. I doubt I'll be sitting there for 10 minutes for warmup, I like to get up in the air fast.

I'll set the environment to super cold see how it all goes. This is the beauty of a sim, we can do all these things and even take off from the Apron (which I often do)

I did something similar after watching the training films. I would get up to altitude, and then simulate what I would do for certain emergencies (engine fire, oil pressure loss, engine failure, runaway turbo, etc.). Going through the motions from the training videos until it becomes habit actually helped. I had a fuel or oil leak (can't remember which) that caused a fire in E3. Without even thinking I had the fire out and the engine secure in seconds. It's nice to have the muscle memory there so when an emergency does happen, you're not blindly looking around the cockpit for levers and switches you rarely use.