Soldato
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The f1 car sticking to the roof off a tunnel upside down myth.
What Myth would you want to see busted?
- Thread starter Linkex
- Start date
You'd like to see it busted? I thought you believed in GW?
Associate
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Reading this thread is now making my head spin at approximately 100,000 RPM wrt my own freakin neck!
Soldato
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given a tunnel with sides where you could do this and an engine that worked well enough upside down there is no reason why it wouldnt work.
the tricky bit is finding the tunnel, because you'd need a massively long tunnel thats very nearly circular, has a very wide diameter and has no signs or fans on the roof
as long as the car is going fast enough i cant see why it couldnt give itself enough downforce (upforce) to press itself hard enough into the roof of the tunnel to keep it there and critically give itself enough grip to maintain its speed without getting bucketloads of wheelspin
*edit*
seeing that F1 teams claim that their cars can make several thousand pounds of downforce, and the cars weigh a fair amount under 2000 pounds (i dont know the exact figures, but they cant be more than 900kg) i would say that they might just manage it at a very high speed
kinda rests on the real downforce values though
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That position was what I was giving him credit for in earlier posts because it could be true in principle in some theoretical gas-turbine engine that could just do whatever rpm it wants wrt to it's non-rotating case. That's why I threw the speed limited piston engine into the mix. But now Glacus has revealed it is just a major fundamental lack of understanding/inability to add two opposing angular velocities together.
Glacus what do you have to say about my simplified example in post 69?
Sorry thread/everyone - I'm suffering from bad 'someone on the internet is wrong'. Not normally affected. Should just go and have dinner.
They aren't right at all.
You don't need to know inner workings of hellicopters. You need to know very basic workings of an engine and some basic physics that's it.for the simple version. If you expand it to what would actually happen, you need to know much more details.
- wrong, the engine casing is mounted to the body, but the internals or an engine, can very very much move independent of the body of the helicopter.
Otherwise you are saying that you can't have a car engine ticking over with no movement.
- above explains. Engine casing is attached, not internals, the blades are directly connected to the internals, not the casing. So they are independent.
-yes rpm does dictate speed. But is irrelevant. You don't even need to be thinking about this.
-well for that you need to go into far more detail than the basic myth. A quick google suggest helicopter blades spin between 250-500rpm, it is very unlikely the helicopters frame could stand those huge forces it is not designed to take. But this is outside the basic concept.
A helicopters blades do not rotate freely, they are driven. If the drive shaft is rotating the blades at 100RPM but the drive shaft is being rotated at 100RPM in the other direction, the blades will not be moving relative to the air.
Lol
The drive shaft is not being rotted in the opposit direction.
Here is where you are going wrong. What's rotating it, in the other direction.
Certain parts of the internals are on bearings but not all of them. If they were all on bearings then there would be no way for the forces from the engine to be transferred to the drive shaft as everything would freely rotate relative to each other.
EDIT: You have agreed in an earlier post that if the turntable was rotated when the blades are not being driven, the blades would rotate at the speed of the turntable. Why do they not just remain stationary relative to the air while the helicopter + turntable rotate below them?
Associate
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You're getting yourself confused between the helicopter/turntable and aeroplane/treadmill scenarios.
On an aeroplane, the wheels (affected by the treadmill) and the engine and wings are completely independent hence why the aeroplane takes off as normal.
On a helicopter, the body and blades directly affect each other. If uncorrected, the blades on a helicopter actually spin the helicopter body itself around. That's why you need a tail rotor to counteract this force. The tail rotor is not designed to be strong enough to overcome a turntable with equal force to the total force generated by the engine/blades hence why the helicopter would be unable to take off.
Soldato
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looks like you need to understand the basic working of a car engine then. the only reason a car engine can stay at idle without the car moving is the clutch. every single learner driver in existence will know that the car rolls at a few mph while idle.
same applies for a helicopter, but this time the blades will be going round very slowly and i really doubt they'd gove any lift
as for the 250RPM, i am pretty sure that every single helicopter in existence will have a gearbox of some sort to reduce the speed of the engine down by some. before you say so its unlikely to be a car gearbox with 5 speeds and reverse, just some cogs to slow the rotation down so the blades get to a decent speed at the engines optimum power
Good god, this is such fail.
In an engine you have pistons, these move and rotate a crankshaft. It makes no difference what forces the Engine as a hole is experiencing, as the pistons are still moving up and down and rotating the propshaft. So no, there is no direct link of force between the crankshaft and engine.
Actually I didn't agree to that. But that would be sort of correct. But this is totally off topic and isn't related at all and even more complicated. Bearings aren't 100% resistance free and if you've ever tried to bump start a car, you realise how much resistance an engine produces when being turned over when off.
Not that helicopter uses a piston engine, but the basic physics is the same for when engine is running.
Glacus - with respect you're talking utter nonsense now. Your mocking tone doesn't help given the hole you're digging. Keep it simple - address this...
your confusing yourself,
You are saying an engine is directly linked to the chassis. So regardless of clutch, the chassis should move. A clutch only disconnects propshaft, it doesn't disconnect the whole engine. This is what you are saying not me.
This again is totally irrelevant to the question.
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Caporegime
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This is amazing
The other stuff where everyone's getting all 'spergy about things they don't understand? Not so much.
Man of Honour
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So why did their greatest enemy concede victory?
Digging a hole, I'm really not. You are as blind as the people who think a plane does not take of on a runway. A twisted logic though not enough knowledge. Yours is the same, you believe you are right, but you really aren't.
Again you need to look at where the forces are directly linked.
Cars tyres rotate, a conveyer belt moves and is in direct contact with tyres. Therefore forces are directly link, they cancel each other out and car stays stationery.
On a plane the force comes through the engine and into the prop, which moves air and pulls plane forward, the conveyor belt is in contact with the tyres. No directl link between forces. Plane moves forward and takes off. Only real difference is wheels move twice as fast.
On to helicopter. Turntable is linked to helicopter boady. Engine internals can still operate and connected to blades. No dirt link between forces. Blades can still spin.