B-17 Carb Ice Issues

[WB_FlashOver]

Good day and Happy New Year,

Today a couple friends and I decided to go on a bomber mission from Biggin Hill, UK to Peenemunde, Germany. Two of us were in our hardstands for about 20 minutes before attempting to start engines. When ready the engines would not start or would start and die. We tried Auto Start with same results. We determined that our carburetors were frozen solid. We exited the game, relaunched and immediately hit auto start and all was good so long as we kept the intercoolers on hot and around 4 on turbo dial. After flight I went back to Biggin Hill and reloaded ASP4 and then loaded the Tracer option in LINDA while monitoring Eng1_Carbice_Factor. Please see video below.

I don't think the carbs should be icing up prior to engine start.
Roger

[alan CXA651]

Hi Roger.
I found ASN on occasions played hell with any A2A aircraft in different ways , i came to the conclusion that ASN got a weather update from the nearest weather station that was corrupt , then ASN converted this corrupt weather to the sims weather via simconnect , which in turn corrupted any A2A aircraft i was flying at the time , on the B17 it seemed to effect the engines , on the P51 it made the controls hyper sensative .
This mainly happened on weekends , bank holidays in UK , when some weather stations go off line for servicing , and i might only get part of a weather update from that station , which then caused the corruption .
A2A aircraft rely on simconnect so they get effected more than some aircraft , this theory is just an educated guess , as i could never get conclusive proof of this , but i have not used ASN for ages , and all my A2A aircraft have been perfect since , apart from the usual A2A ware / tare, and occasional failures , more so when on a 91st bomb mission and i have the pucker module active , when flak can damage the B17 .
regards alan.

[WB_FlashOver]

Thanks for the reply Alan, I've had AS mess with my sim too. However, this is not an AS issue. I have been working on a modified Crew Report (Shift + 2). I have Carb Ice and Body Ice on it. In order to verify that it is reporting these items I created custom weather using P3Dv4 weather engine. I can verify through this process that carb ice develops in the B-17 carbs without engines running but does not develop in carbs on my other A2A planes until I start engines, i.e. Comanche, Connie, P-51, etc.

Cheers
Roger

[WB_FlashOver]

I'm curious if anyone has been able to confirm this issue? My testing is done at Bandon (S05) but that should not matter. Below is the weather I have created to induce icing, no AS used. I can switch to the Connie, P-51, Comanche, etc and ice only forms if engines are running. The B-17 however will have 5% carb ice within seconds without engines running.







Thanks much
Roger

[FireRescue85]

Hey Roger,

This has been an issue since it’s inception. I fly in the northeast, where we have snow for 7 months out of the year, and if I don’t keep turbos on 4+ while starting, within seconds the carbs ice and I can’t start it. As far as a real B-17, I’m not sure how fast they were susceptible to carb icing while starting, so I can’t say if it’s accurate or not.

-Scott

[WB_FlashOver]

Hey Roger,

This has been an issue since it’s inception. I fly in the northeast, where we have snow for 7 months out of the year, and if I don’t keep turbos on 4+ while starting, within seconds the carbs ice and I can’t start it. As far as a real B-17, I’m not sure how fast they were susceptible to carb icing while starting, so I can’t say if it’s accurate or not.

-Scott

Thank you, Scott, for the reply. Today I got curious and fired up FSX-SE (glad I did not uninstall it yet ) to see if carb icing happens without engines running there as well. Well... ... blow my dress up, it does. I never caught that in over 1300 hours. So after a few minutes of practice I found the trick to starting the old girl in this type of weather. As you say 4+ on turbos will warm the carbs quickly once engine is started. Intercoolers hot. Mixture on Rich seems very helpful as mixture on Auto-Rich requires many pumps on the primer but Rich only requires 2, maybe three pumps. I let the plane sit there for about 10 minutes at which time I had 85% carb ice. I Used the method above and they all started promptly and carb ice went away within minutes. I still say there is an issue that carbs ice up when engines are not running but now that I have a work-a-round I'm all good. None of the other A2A planes will develop carb ice until engines are started and then you have watch them closely.

Cheers
Roger

[FireRescue85]

Roger,

I’m curious if it’s due to the fact that it’s an early project from A2A, so maybe their carb ice coding isn’t the most advanced? I know the 377 has a carb heat switch, so icing isn’t as noticeable (flip the switch when temps are cold and forget about it lol)

-Scott

[GL_64]

In a related issue, I handover control of cowl flaps and rpm etc to copilot. But I keep getting Carbs Overheating message.

What am not doing properly ?

Thnx.

[WB_FlashOver]

Turbos have a huge effect on carb temps. It is a balance between throttles, Intercoolers & Turbos. Sometimes you have to pull turbos back and increase throttles while managing the intercoolers to keep them cool. Carb filters can have an effect on carb temps too but you need to manage them by the book. If the Co-Pilot is handling Intercoolers then the trouble I've run in to is that he fiddles and diddles with the levers constantly and cannot get them right. If you can get a control to run them yourself I'd recommend that. Maintaining proper temps in the carbs is a constant battle in the B-17, whether they be hot or cold.

Roger

[GL_64]

Thnx for that.

Think it's time to read the manual