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 Post subject: Lewis Have A Question
PostPosted: Mon Mar 14, 2016 9:13 pm 
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If Your Flying the A2A Cub Inverted Can you Hurt the Motor ? Greatengine


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PostPosted: Tue Mar 15, 2016 6:23 am 
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My name is not Lewis but I'm gonna answer anyways if that's ok!? :wink:

Yes you can! When flying inverted the oil pump will not be able to suck in oil and thus the engine will loose the oil pressure. You can argue that the engine will also stall because you won't have a fuel supply either when inverted but due to the windmilling of the propeller the engine will still turn.

So inverted = no oil pressure = engine damage (at least in planes that are not equipment with aerobatic engines which have a dry sump lubrication system.)

Happy flying

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PostPosted: Tue Mar 15, 2016 6:36 am 
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Hi,

Technically it will die out of fuel starvation shortly, since it is a carburetor fed engine and once inverted the fuel level in the carburetor is disrupted.
The main damage may come from the fact, that there will be not enough oil to lubricate the crankshaft and cool the engine, since the plane is inverted the crankcase will be dry. The engine needs to run some time without proper lubrication to start overheating and get damaged.(However this process depends entirely on the conditions: amount of lubrication left, engine rpm and engine cooling) I am sure Mr. Henriques from A2A and other guys that are real world pilots will be able to provide more details on the matter. I hope this explains the basics. :mrgreen:

Cheerz,
Will

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PostPosted: Tue Mar 15, 2016 7:15 am 
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LZ-WIL wrote:
Technically it will die out of fuel starvation shortly, since it is a carburetor fed engine and once inverted the fuel level in the carburetor is disrupted.
The main damage may come from the fact, that there will be not enough oil to lubricate the crankshaft and cool the engine, since the plane is inverted the crankcase will be dry. The engine needs to run some time without proper lubrication to start overheating and get damaged.(However this process depends entirely on the conditions: amount of lubrication left, engine rpm and engine cooling) I am sure Mr. Henriques from A2A and other guys that are real world pilots will be able to provide more details on the matter. I hope this explains the basics. :mrgreen:

I don't think that overheating will be a problem in those circumstances. First of all in a small engine like this the majority of the cooling is done by airflow anyways. Secondly if there is no fuel supply there will be no combustion and without combustion there will not be a lot of heat generated. Of course you'll always generate some heat due to friction but that won't overheat the engine.

The problem if there's no lubrication will be that the crankshaft/crankcase, crankshaft/conrod, piston/cylinder etc. will be not lubricated. Meaning that there won't be a protecting oil film I between the moving metal parts. Actually there will be direct metal to metal contact of moving parts which will actually break your engine. The engine will seize.

Happy flying

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PostPosted: Tue Mar 15, 2016 8:01 am 
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LZ-WIL wrote:
The engine needs to run some time without proper lubrication to start overheating and get damaged.(However this process depends entirely on the conditions: amount of lubrication left, engine rpm and engine cooling)


You are right in this particular case of engine being inverted, no combustion and a lot of aircooling. I was more likely talking in general in this paragraph, if the engine is put to oil starvation that it will start generating more heat than usual. :wink:

Cheerz,
Will

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PostPosted: Tue Mar 15, 2016 10:42 am 
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Yes you're right. A sign of oilstarvation should be rising oil temperatures and sinking oil pressure. Finally the engine won't die due to higher temps though I believe. It'll seize due to a lack of lubrication. At least with those relatively low power engines.

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PostPosted: Tue Mar 15, 2016 11:24 am 
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I think the guys have you covered pretty well, but yes your going to do a bit of bad and wont be flying for too long inverted in a little standard cub.

thanks,
Lewis

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PostPosted: Tue Mar 15, 2016 11:29 am 
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Exactly,

Brutal metal to metal friction without oil lubrication will bring moving parts (crankshaft, pistons etc.) to stand still and engine to a complete blockage.

Cheerz,
Will

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PostPosted: Tue Mar 15, 2016 11:30 am 
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Agreed :wink: :D

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PostPosted: Tue Mar 15, 2016 11:39 am 
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Why on earth would you want to fly inverted in the Cub anyway.

Cheers Chris


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PostPosted: Tue Mar 15, 2016 8:33 pm 
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Piper_EEWL wrote:
My name is not Lewis but I'm gonna answer anyways if that's ok!? :wink:

Yes you can! When flying inverted the oil pump will not be able to suck in oil and thus the engine will loose the oil pressure. You can argue that the engine will also stall because you won't have a fuel supply either when inverted but due to the windmilling of the propeller the engine will still turn.

So inverted = no oil pressure = engine damage (at least in planes that are not equipment with aerobatic engines which have a dry sump lubrication system.)

Happy flying

Thanks Piper for the great answer I figured it would not be so good. Heidi Didn't like it to well. I just wanted to invert to see what action she would have. also I just wanted to invert this cub to see If I could do it I did . but won't be anymore. Thanks for quick answer Greatengine.


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PostPosted: Tue Mar 15, 2016 8:39 pm 
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speedy70 wrote:
Why on earth would you want to fly inverted in the Cub anyway.

Cheers Chris

Hi Speedy 70 I had Heidi Going for a ride so I just inverted to see what she had to say. Also I just wanted to Invert just for the challenge Thanks for answering me. Greatengine.


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PostPosted: Tue Mar 15, 2016 8:44 pm 
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LZ-WIL wrote:
Exactly,

Brutal metal to metal friction without oil lubrication will bring moving parts (crankshaft, pistons etc.) to stand still and engine to a complete blockage.

Cheerz,
Will

Hi Thanks for your great answer After hearing all the problems I won't be flying Inverted in the A2A cub anymore Thanks again Greatengine.


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PostPosted: Tue Mar 15, 2016 8:48 pm 
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Piper_EEWL wrote:
Agreed :wink: :D

Thanks for the answers Greatengine


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PostPosted: Tue Mar 15, 2016 11:53 pm 
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greatengine wrote:
Thanks Piper for the great answer I figured it would not be so good. Heidi Didn't like it to well. I just wanted to invert to see what action she would have. also I just wanted to invert this cub to see If I could do it I did . but won't be anymore. Thanks for quick answer Greatengine.

You're very welcome. Well that's the beauty of the simulator. You can try stuff that would be risky for the plane or your health without jeopardizing either one in RL. The only thing you risk in the sim (at least with the A2A planes) is your hard earned hours on engine and airframe :wink: I tried to loop the B-17 the other day just to see what would happen. It worked! And I didn't break anything. The crew wasn't to happy with this maneuver though 8)

Happy flying

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