I fly the 520 verson. I'm not sure to understand what is described in the cold starting procedure. It says "full throttle" but, even with the pump running, I have to crank the engine for at least 20/30 seconds and when it starts, the engine jumps to 1500 RPM before I can reduce. Not very good on a cold engine. No priming on a fuel injected engine ?
What is the purpose of the "Alternate air" stuff on the Dashboard ? The pilot guide refers to "Alternator air" but with no further explanations (unless I missed it).
Thanks.
Starting procedure and "alternate air"
- guillaume78150
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Re: Starting procedure and "alternate air"
Use of full throttle is when priming. During actual starting, have it partially opened as usual.
Alternate air control provides air from the engine compartment to the engine induction, bypassing the air filter. No much use in the simulator, I recon.
-Esa
Alternate air control provides air from the engine compartment to the engine induction, bypassing the air filter. No much use in the simulator, I recon.
-Esa
- guillaume78150
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Re: Starting procedure and "alternate air"
Thanks Esa, how priming the Bonanza engine ? Cranking with no ignition ?
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Re: Starting procedure and "alternate air"
just follow the checklist on page 70 in the manual:
ENGINE STARTING
1. Mixture - RICH
2. Prop - FULL
3. Throttle - FULL
4. BAT and ALT switches - ON
5. Check Gear Lights - GREEN
6. AUX Pump - ON until ff goes into the green then OFF
7. Throttle - Cracked ¼†(Clear prop!)
8. Mag/Start Switch - START
ENGINE STARTING
1. Mixture - RICH
2. Prop - FULL
3. Throttle - FULL
4. BAT and ALT switches - ON
5. Check Gear Lights - GREEN
6. AUX Pump - ON until ff goes into the green then OFF
7. Throttle - Cracked ¼†(Clear prop!)
8. Mag/Start Switch - START
Kind Regards
Tomas
Sim: FSX SE
Accu-Sim aircraft in my hangar:
C172, C182, P51 Civ, P51 Mil, B17, Spitfire, P47, B377 COTS,
J3 Cub, T6, Connie, P-40, V35B
A2A Accu-Sim Avro Lancaster Loading:............0.000003% complete, please wait.
Tomas
Sim: FSX SE
Accu-Sim aircraft in my hangar:
C172, C182, P51 Civ, P51 Mil, B17, Spitfire, P47, B377 COTS,
J3 Cub, T6, Connie, P-40, V35B
A2A Accu-Sim Avro Lancaster Loading:............0.000003% complete, please wait.
- guillaume78150
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Re: Starting procedure and "alternate air"
Thanks, but what does "Cracked ¼†mean ?
Re: Starting procedure and "alternate air"
Throttle moved forward 1/4 inch.
Flight Simmer since 1983. PP ASEL IR Tailwheel
N28021 1979 Super Viking 17-30A
N28021 1979 Super Viking 17-30A
- guillaume78150
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Re: Starting procedure and "alternate air"
Clear now.
Thanks !
G.
Thanks !
G.
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Re: Starting procedure and "alternate air"
I get near instant starts by opening the mixture fully, throttle to 25%, run the pump until the needle stops climbing and then cranking. I get a near instant start and 900 RPM idle.
- DHenriques_
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Re: Starting procedure and "alternate air"
There was a 520 engine in the Bo I flew years ago and as I recall the procedure for a normal start was to go to full throttle, start the pump and run it until it peaked then OFF. Then go to 1/4 throttle and start.AviationAtWar wrote:I get near instant starts by opening the mixture fully, throttle to 25%, run the pump until the needle stops climbing and then cranking. I get a near instant start and 900 RPM idle.
Sounds like this is what you might be doing.
Worked fine for us !
Dudley Henriques
Re: Starting procedure and "alternate air"
Regarding starting method of Continentals...
IO-Continentals are fuel-injected engines that feed the fuel into the engine in proportion to the RPM (simply because the fuel pump speed varies with engine RPM), and throttle+mixture positions. Throttle position alters the fuel flow into the engine mechanically as per fuel unit's adjustment, there are no means in place to measure the actual air flow going into the engine. So, given RPM + given throttle position + given mixture position = certain fuel flow, always (not speaking of altitude compensated thingies).
When you run the boost pump, the flow provided by it is obviously unaffected by the engine RPM, so it works when the engine is shut down. What affects the fuel flow into the engine are the throttle and the mixture alone. (This is why you are instructed to go full with it when priming - not really necessary, but this provides most fuel flow. Mixture is defaulted full-rich, which is the starting position.) This is the reason for different handling of the throttle during the startup of Continentals versus IO-Lycomings, which are effectively pressure carburetted engines.
-Esa
IO-Continentals are fuel-injected engines that feed the fuel into the engine in proportion to the RPM (simply because the fuel pump speed varies with engine RPM), and throttle+mixture positions. Throttle position alters the fuel flow into the engine mechanically as per fuel unit's adjustment, there are no means in place to measure the actual air flow going into the engine. So, given RPM + given throttle position + given mixture position = certain fuel flow, always (not speaking of altitude compensated thingies).
When you run the boost pump, the flow provided by it is obviously unaffected by the engine RPM, so it works when the engine is shut down. What affects the fuel flow into the engine are the throttle and the mixture alone. (This is why you are instructed to go full with it when priming - not really necessary, but this provides most fuel flow. Mixture is defaulted full-rich, which is the starting position.) This is the reason for different handling of the throttle during the startup of Continentals versus IO-Lycomings, which are effectively pressure carburetted engines.
-Esa
- guillaume78150
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Re: Starting procedure and "alternate air"
It works indeed differently from the Comanche… Thanks for the explanation.
- Piper_EEWL
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Re: Starting procedure and "alternate air"
That’s mostly because the Comanche has a carburetor and is not fuel injected. You would have to compare. It to the Cessna 182T which has a IO-Lycoming.guillaume78150 wrote:It works indeed differently from the Comanche… Thanks for the explanation.
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Re: Starting procedure and "alternate air"
This constantly floods my engine.. I'm still to find out the proper way I guessDHenriquesA2A wrote:for a normal start was to go to full throttle, start the pump and run it until it peaked then OFF. Then go to 1/4 throttle and start.
Dudley Henriques
- cristi.neagu
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Re: Starting procedure and "alternate air"
Best way I found was suggested on this forum. Mixture full rich, throttle 50%, aux pump on until the needle just hits the green arc (don't delay, be as quick as possible), throttle 10-20%, crank. Works really well.
- guillaume78150
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Re: Starting procedure and "alternate air"
Another trick, Don't let the engine at idle or when taxiing without leaning. Spark plugs are quickly fouled on the Bonanza.
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