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PostPosted: Sat Sep 30, 2017 9:55 am 
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Airman

Joined: Fri Sep 29, 2017 5:16 am
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Yes Nick, I have tried it at varying throttle settings including full open and various priming periods.

https://youtu.be/mSaowhT0JbM I have uploaded the video to Youtube. Dont know if the forum will strip out the link. We shall see!

Regards
John Earl


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PostPosted: Sat Sep 30, 2017 10:09 am 
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Thanks for the video John - it really helps. I reckon you're priming for too long (about 18 seconds in that vid) and flooding the engine. If you go to the hangar immediately after your attempt to start, it should show you if this is the case.

Try this:

Mixture cut-off
Fuel pump on
Mixture full rich
Count to five!
Mixture cut-off
Fuel pump off
Then mag switch to start...

Cheers,
Nick


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PostPosted: Sat Sep 30, 2017 10:13 am 
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Airman

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Ok Nick, I will try it again.

Thanks
John Earl


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PostPosted: Sat Sep 30, 2017 10:16 am 
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Okay - let us know how you go. :) The only other thing I can think of is water in the fuel, but that would presumably be shown in the hangar and you should certainly see it if you've completed the external pre-flight checks.

Nick


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PostPosted: Sat Sep 30, 2017 12:13 pm 
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Yes, that is definitely over-primed, though it still ought to at least attempt after some serious cranking.

Recall: pump on, then with the mixture lever, push it in for a couple of seconds to introduce fuel, then pull it back out, then pump back off. So, pump on - mixture in - one...two...three... - mixture out - pump off.

-Esa


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PostPosted: Sat Sep 30, 2017 1:27 pm 
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Location: Typically hanging around N07, 12N, KLDJ, KCDW
That is seriously overprimed. It is 5 seconds at most, as Nick noted that was 18 seconds of priming!

The checklist steps are not being followed in the correct order. The steps do need to be performed in sequence or else the results will not be correct.

The throttle needs to be opened before priming. Then the pump is turned on, then the mixture is opened, count to 5 seconds, then close the mixture and then turn off the pump.

The fuel injection system on these engines is a constant flow type and not a metered pulse. You want to get just enough fuel in the intakes to start, but not let it pool up or keep flowing continuously into the intake even after the pump is cut off.

It also appears that the throttle was moved open while priming. That will further increase priming fuel flow and you don't want that here. The the throttle is pulled back out, but I'm not sure if it was left partially open. The engine will not start with a throttle that is closed. Lastly, do not most the mixture forward until the engine actually starts. That will flood the engine and cause a fire. Fires are simulated in A2A, though I'm not sure if it simulates a fire due to overpriming. I've seen it happen IRL and it doesn't take too much excess prime before fuel starts pouring out the exhaust pipe.

I'm sure the start will be much easier once the priming is reduced and the steps are followed in the correct sequence.

_________________
Flight Simmer since 1983. Private Pilot
Paramus Flying Club http://www.flyingclub.org


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PostPosted: Sat Sep 30, 2017 1:35 pm 
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Airman

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Ok Guys, hands up I was flooding the engine. By reducing the priming period to strictly between 3 & 5 secs the engine fires ok.

Thanks for all the help and time taken by those who replied.

Regards
John Earl


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PostPosted: Sat Sep 30, 2017 1:36 pm 
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Chief Master Sergeant
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Location: Typically hanging around N07, 12N, KLDJ, KCDW
Good to hear. In cold weather you may find it takes a tiny bit more prime and in hot weather or with an engine that still shows as hot on the gauges you may no prime or just a little for a start.

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Flight Simmer since 1983. Private Pilot
Paramus Flying Club http://www.flyingclub.org


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PostPosted: Sat Sep 30, 2017 1:51 pm 
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Thanks. There is obviously more to this simulation than at 1st meets the eye. I need to have patience and perseverance!

Regards
John Earl


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PostPosted: Sat Sep 30, 2017 1:56 pm 
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Location: Typically hanging around N07, 12N, KLDJ, KCDW
It is the closest one that we have to reality IMO. The airplanes even develop a little personality as they wear and tear if you just do oil changes and repair broken parts as you discover them.

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Paramus Flying Club http://www.flyingclub.org


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PostPosted: Sat Sep 30, 2017 2:12 pm 
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Glad to hear you cracked the manual engine start John. And, yeah, these wonderful recreations of 'simple' little GA aircraft have plenty of depth in terms of the flight model, engine simulation and avionics functions.

Welcome to the forums here and don't hesitate to post if you have any more issues or questions. :wink:

Cheers,
Nick


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PostPosted: Sat Sep 30, 2017 2:30 pm 
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Airman

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Thanks Nick. Even at 70 years old, I still have a lot to learn!

Regards
John Earl


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PostPosted: Sat Sep 30, 2017 2:40 pm 
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John, it was my granddad who really got me into the MS flight simulators back in the mid 1990s, and he said much the same thing. Though he's been gone a few years, he was an electrical and mechanical engineer in the British Army and I often think these simulations would be right up his street. :)

All the best,
Nick


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PostPosted: Sat Sep 30, 2017 2:57 pm 
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Airman

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They sure would Nick. I too was an E&M engineer and its something about the complexity of the simulations available to a humble PC user that appeals to our engineering psyche!

I have also, finally got around to doing something I have been meaning to do for years and that is taking PPL lessons. I fly a C152 but the feel of the A2A C172 simulation is very similar to the real world C152, even to the time it takes for the oil to reach operating temperature. I don't have a force feedback yoke, so when I say "feel" I mean the way the simulation responds to control inputs.

I don't have a grandson old enough yet to enjoy MSFS, but I have got my nephew interested! He is a P3D student but I wont hold that against him!

Regards
John Earl


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PostPosted: Sat Sep 30, 2017 3:37 pm 
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That's interesting to hear John - I'm pretty confident you're going to enjoy getting to grips with the A2A sims in that case.

And best of luck with the PPL training. I'm not one of them, but there are quite a few real world pilots including some CFIs/CFIIs who are members of the community here. Maybe it's something I'll be able to pursue one of these days, but in the meantime there's FSX/P3D! :wink:

Regards,
Nick


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