C172 Trainer Engine Start

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jsearl_98
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C172 Trainer Engine Start

Post by jsearl_98 »

Just started using the C172 Trainer - very impressed so far. One problem, I cannot manually start the engine. I am (I think) following the start procedure correctly but the engine only cranks over and doesn't fire. Also have used engine heater. Auto-Start is fine.

Any ideas please?

Thanks
John Earl

Tomas Linnet
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Re: C172 Trainer Engine Start

Post by Tomas Linnet »

Hi and welcome to the world of Accu-Sim

First , please make sure your new C172 is updated if you use FSX or FSX Steam. If you are using P4Dv4, you should be good. Here's the update: https://a2asimulations.com/forum/viewto ... 29&t=57819

Make sure to preflight the aircraft and also note the default fuel and load manager won't work for the A2A addons. Use "Shift +4" for the correct one.
Make sure the fuel cut off knob is in before attempting to start.
The start procedure is in the manual make sure to have the mixture in idle cut off and don't prime to much. The fact that auto start is working suggests it's pilot error :D it happened to me as well so don't worry to much about it
Kind Regards
Tomas

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LZ-WIL
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Re: C172 Trainer Engine Start

Post by LZ-WIL »

Hi John and welcome to the forum,

I would recommend as a start to get acquainted with the 172 manual provided by A2A. The aircraft is very accurately modeled and should be treated as the real thing.
Do you prime the engine before start? Is everything OK in the flight hangar "Shift+7" menu? These are few of the things you should check if the engine refuses to start in the normal way.

Cheerz,
Will
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Oracle427
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Re: C172 Trainer Engine Start

Post by Oracle427 »

Fuel, air, spark.

First is to make sure you have fuel.
1 Is the fuel selector set to both?
2 Is the fuel cutoff knob pushed in?
3 Is the throttle open? I find it needs about 20-25% which is a bit much IMO, but that's what it takes for this one.
4 Did you prime for about 3-5 seconds with a cold engine by turning on the fuel pump. moving the mixture all the way forward, counting and then pulling the mixture back to cutoff? The fuel flew gauge should have registered some movement and the pump sound should have changed slightly as it took in fuel.

For air, as long as the throttle is open to at least 20% you'll have enough for a start.

Then you need spark.
1 Turn the key to the start position and crank the prop about 5 blades at which point you should hear the engine fire.
2 Without a moment's hesitation when the engine fires, promptly push the push mixture all the way forward to get fuel flowering into the engine. If you delay, the engine will fall to start and will need to be reprimed by following the above steps.

Don't overprime as that will prevent the engine from starting due to a bad fuel/air ratio. In sim, you will need to followa flooded engine start procedure or go to the maintenance hangar to fix it. IRL, that can also result in an engine fire and/or damaged exhaust components.

A hot engine calls for trying a start without priming. If it fails to start, try a little priming.

I don't believe Accusim simulates vapor forming in hot fuel lines in recently flown aircraft, if it did I'm sure there would be a lot more complaints about difficulty in starting fuel injected aircraft! LOL

Hopefully this helps. The biggest problem I had was trying to find the right throttle position. IRL, I barely open the throttle by moving it forward at most 1/4". That amounts to maybe 5% of the travel. In sim, you need to open it substantially more for a start.
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Lewis - A2A
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Re: C172 Trainer Engine Start

Post by Lewis - A2A »

Hello John and welcome to the forums,

I see the community have the basics covered. So long as that auto start works everything from a technical pov is good so it'll be just something you are missing or something that needs a slight tweak, be it little more prime or a little less etc. The engines all dynamic, its an actual combustion engine simulate under the hood so you have a bunch of things happened that can mean just like in reality a few extra crank over a checklist may sometimes be needed.

thanks,
Lewis
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jsearl_98
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Re: C172 Trainer Engine Start

Post by jsearl_98 »

Thanks for all the replies.

The frustrating thing is, I have done everything that was suggested in the various replies before I posted. I read the manual, pretty well from cover to cover, and certainly the areas that covered the engine, fuel, start procedures etc. etc.

I have been to the maintenance hangar, (after a few failed start attempts) performed a complete overhaul and got the report "...excellent shape." The plugs are not fouled, the battery is fully charged and there is a total of 14 gallons of fuel in the tanks, fuel shut-off is in (on), fuel selector set to both. I have followed the start procedure (its not rocket science after all), Master Alt and Batt On, Mixture control - full in 100%, run fuel pump for 5 seconds. Note a deflection on the fuel flow gauge. Fuel pump off, Mixture 0%, throttle 20%, crank engine (key to "Start") until battery is exhausted. But yet the engine stubbornly refuses to fire.

So if I'm doing something wrong (which I am perfectly willing to accept), I for the life of me can't see what it is.

Regards
John Earl

(PS I downloaded the update also.)

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Oracle427
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Re: C172 Trainer Engine Start

Post by Oracle427 »

Does Ctrl-E work?

You should hear a brief little rumble when the engine catches. It's not the same as being in there with all the vibration when the engine starts to catch, but it sounds about right.

Also confirm that you are using the shift-4 screen to manage fuel.
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Nick - A2A
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Re: C172 Trainer Engine Start

Post by Nick - A2A »

Hi John,

One other little question which may help us: what's the outside air temperature and do you use any add-on weather software? (OK - 2 questions! :wink:)

Thanks,
Nick

jsearl_98
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Re: C172 Trainer Engine Start

Post by jsearl_98 »

Yes I use shift 4 for loading fuel, and auto-start on shift 3 works fine. I am not using any weather add-ons and ambient is around 15C.

I did a video of my start procedure but its to big to post as an MP4 file. A WMV file doesn't seem to have sufficient clarity.

Regards
John Earl

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Oracle427
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Re: C172 Trainer Engine Start

Post by Oracle427 »

Nothing can be attached to the forum irrespective of size. You will need to upload the video to a file sharing site and share a link or embed from there.

A bit of a head scratcher.
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Nick - A2A
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Re: C172 Trainer Engine Start

Post by Nick - A2A »

Yeah, strange you're having problems John as it does sound as though you're carrying-out the procedure correctly. A video will certainly help to tell though. Assuming you're starting 'cold and dark', 5 seconds of priming should work fine at 15°C OAT, but you could always try varying the amount of time that you prime for, just in case you're flooding the engine.

However, if the engine is flooded, it should show next time you visit the maintenance hangar.

Nick

jsearl_98
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Re: C172 Trainer Engine Start

Post by jsearl_98 »

Thanks Nick. I shall persevere. There has to be a solution.

Strangely, I had a similar problem with a Merlin engined Lancaster. Never could get those beasts to fire up except by using Ctrl + E.

And before the conspiracy theorists cry "Ha - Ha", it was FS2004 and on a different PC!

Regards
John Earl

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AKar
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Re: C172 Trainer Engine Start

Post by AKar »

Do you use some button to engage starter, or drag the key with a mouse? Looking at the problem from a real engine point-of-view, if it doesn't even attempt to catch, just about the only thing that comes to my mind is that the mags fail to fire.

-Esa

jsearl_98
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Re: C172 Trainer Engine Start

Post by jsearl_98 »

Drag the key with the mouse. That is the impression I get - that the engine is not firing - there is no indication of the engine even kicking into life.

Regards
John Earl

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Nick - A2A
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Re: C172 Trainer Engine Start

Post by Nick - A2A »

Any chance you can find somewhere to upload that vid John? If auto-start is working and you checked the condition of the mags in the hangar, it seems to rule out any simulated components failures so to speak. Also, have you tried starting it with the throttle well open (say at 50 or even 100%)? Though this obviously isn't recommended in the real thing, it should help to rule out the issue being the throttle position.

Thanks,
Nick

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