"How to Start the B-17 Engine"
Fri Feb 11, 2011 9:27 pm
Just found this on Youtube, may be old to many but I had never seen it
http://www.youtube.com/watch?v=vOl5YpFV ... grec_index
Maybe a B-17 crew member can chime in, what's the deal with the mixture controls? Is it full aft for rich or is there some kind of ground lean they need to go to as soon as the engine starts?
-Tim
Anyone know how embed a video in a post?
http://www.youtube.com/watch?v=vOl5YpFV ... grec_index
Maybe a B-17 crew member can chime in, what's the deal with the mixture controls? Is it full aft for rich or is there some kind of ground lean they need to go to as soon as the engine starts?
-Tim
Anyone know how embed a video in a post?
Re: "How to Start the B-17 Engine"
Fri Feb 11, 2011 9:58 pm
http://www.youtube.com/watch?v=Bl3b8dYFd1Y This video has your answer I believe.
Now a further question, how many warbirds have the "backward" mixture control?
Now a further question, how many warbirds have the "backward" mixture control?
Re: "How to Start the B-17 Engine"
Fri Feb 11, 2011 10:19 pm
Come to think of it, the Tiger Moth (if you consider it a warbird) has the backwards mixture. There's also a little catch on the throttle that pulls the mixture to full rich as you close the throttle.
-Tim
-Tim
Re: "How to Start the B-17 Engine"
Fri Feb 11, 2011 10:32 pm
Don't know if they still do, but French throttles used to be aft for full throttle and all the way forward for idle, one of the items that needed attention and reversing if an airplane was diverted from French to U.S. or Commonwealth service.
Re: "How to Start the B-17 Engine"
Fri Feb 11, 2011 10:40 pm
Backwards is a perspective thing. All the Harvards I have flown have had a proper mixture control. But those silly yanks have mixed it up on their T-6's and SNJ's. The Wright powered DC-3's also have the mixture controls "backwards" from the P&W powered birds. (Comment does not apply to the Super Dc3) And yes, Tiger Moths, Cornell's Chipmunks and a number of others have their mixture controls oriented differently.
FLy safe,
Glenn
FLy safe,
Glenn
Re: "How to Start the B-17 Engine"
Fri Feb 11, 2011 11:14 pm
The B-29 mixture control is backwards to the engineer. Sitting in the FE seat you push the throttles forward for full power, pull the mixture levers towards you for Auto Rich.
Re: "How to Start the B-17 Engine"
Sat Feb 12, 2011 3:42 pm
The Inspector wrote:Don't know if they still do, but French throttles used to be aft for full throttle and all the way forward for idle, one of the items that needed attention and reversing if an airplane was diverted from French to U.S. or Commonwealth service.
I think that this was pre WW2 that they did this.I have got a Jodel which is French built and this has a normal throttle movement.Also I have flown a Cap10c and that has normal conventional movement,as do infact Rhiems built Cessna 152's.
Re: "How to Start the B-17 Engine"
Mon Feb 14, 2011 5:56 pm
The Moosejaw Belle has a "reversed" mixture control.
It is a Fleet built PT-26.
It is a Fleet built PT-26.
Re: "How to Start the B-17 Engine"
Mon Feb 14, 2011 8:22 pm
We had a T-6 or Harvard in A&P school that was backwards. It took a couple of days trying to run the engine on primer only before it was realized. I can still see the two students trying to run it with large belches of flame wraping around their legs from the exhaust because the side panels were off. 
Re: "How to Start the B-17 Engine"
Mon Feb 14, 2011 8:38 pm
There are differences between the Canadian Harvard models and American T-6s.
In fact, we had a discussion with Transport Canada when we were getting one of our birds re-certified and they wanted us to have one airplane with a mixture control working in the opposite direction as the others.
In the end, we were able to keep them all operating the same direction which is rich towards the tail and lean/cut-off towards the firewall.
In fact, we had a discussion with Transport Canada when we were getting one of our birds re-certified and they wanted us to have one airplane with a mixture control working in the opposite direction as the others.
In the end, we were able to keep them all operating the same direction which is rich towards the tail and lean/cut-off towards the firewall.
Re: "How to Start the B-17 Engine"
Fri Feb 18, 2011 3:17 pm
Yes, the B-17 mixture controls are 'reversed' from what is considered standard. And, this can be a negative transfer in the airplane, particularly during an emergency. One must remain deliberate and focused. Particularly, when flying multiple types.
Full forward position is ICO, ....as we move aft...Auto Lean, Auto Rich, and Emergency Rich (the full aft position). ER was removed circa '47, as per a Bendix Service Bulletin that was issued. So, we simply have Idle Cut Off, AL, and AR, positions these days.
Pressure Carbs, essentially all function the same with some nuances. There is no 'ground lean' in the manner in which you refer to it.
After start, the mixtures may be left in either the AL or AR position, as it makes no difference. I usually move to the AL position upon starting , just in case I perceive an engine may be overly primed a bit, as its easier to 'stroke' the mixture control, in and out of ICO rapidly, to clean up the engine for a normal fuel/air ratio for smooth engine idle. This is just a technique.
To keep it most simple, the Pressure Carb's function is thru air pressure metering, and fuel metering. And, without sufficient differential pressures, the carburetors air and fuel chambers do not function. This occurs when the throttle blades are below about 10 degrees with respect to the closed position stops. In this arena of operation, fuel metering is rendered by an Idle Mixture Valve. This is adjustable and set at a desirable fuel/air ratio out at the carb.
At higher elevation airports , say above 4 or 5 K, it may be necessary to position the mixtures between Auto Lean and Idle Cut Off, (moving the brass mixture control plates) since the Idle Mixture setting may be overly rich, causing the powerplants to load up and quit.
Hope that helps.....
Bob
Full forward position is ICO, ....as we move aft...Auto Lean, Auto Rich, and Emergency Rich (the full aft position). ER was removed circa '47, as per a Bendix Service Bulletin that was issued. So, we simply have Idle Cut Off, AL, and AR, positions these days.
Pressure Carbs, essentially all function the same with some nuances. There is no 'ground lean' in the manner in which you refer to it.
After start, the mixtures may be left in either the AL or AR position, as it makes no difference. I usually move to the AL position upon starting , just in case I perceive an engine may be overly primed a bit, as its easier to 'stroke' the mixture control, in and out of ICO rapidly, to clean up the engine for a normal fuel/air ratio for smooth engine idle. This is just a technique.
To keep it most simple, the Pressure Carb's function is thru air pressure metering, and fuel metering. And, without sufficient differential pressures, the carburetors air and fuel chambers do not function. This occurs when the throttle blades are below about 10 degrees with respect to the closed position stops. In this arena of operation, fuel metering is rendered by an Idle Mixture Valve. This is adjustable and set at a desirable fuel/air ratio out at the carb.
At higher elevation airports , say above 4 or 5 K, it may be necessary to position the mixtures between Auto Lean and Idle Cut Off, (moving the brass mixture control plates) since the Idle Mixture setting may be overly rich, causing the powerplants to load up and quit.
Hope that helps.....
Bob