Comments on: What would happen if you made a Cessna airplane redline on the airspeed?

By: pa28_180flyer

pa28_180flyer — Thu, 13 Nov 2008 22:31:59 +0000

TK...ever heard of a spin??/ At full throttle and a full spin. if you do not take corrective measures real QUICK, you could reach in excess of 150 and more very rapidly!
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By: tk

tk — Thu, 13 Nov 2008 21:58:59 +0000

I believe you are refering to the red arc on the air speed indicator.

The Cessna you are refering to is likely the C172 with a red arc starting at about 150 knots.

I am doubtful that you could ever exceed 150 knots flying straight at the ground with full throttle.

The c-172 has way too much drag and far too little power to go above 120 knots in most variants in normal operations, full throttle and level flight.

However, if you were to get to a theoritical 215 knots you would most probably bend the wings when you encounter turbulence. Hence the do not exceed yellow arc on your speed indicator for smooth air and the top of the green arc for turbulent air. If you operate within these boundaries you will not bend or break the machine. At 215 knots you will likey break the plane, bend a wing, deform the airframe, maybe break off an wing if things go way wrong. In short…..don't abuse your airframe.
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By: al b

al b — Thu, 13 Nov 2008 21:18:59 +0000

If you were to do this you are venturing into unknown territory and you could end up in DR.G's morg. the red line is the maximum speed that the aircraft is designed to go, surpassing that speed could cause structural problems, depending on circumstances of course, but generally not a good plan.
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By: kurimaw

kurimaw — Thu, 13 Nov 2008 21:07:59 +0000

aircraft breakage due to excessive stress receive to the wings and propeller……..

resulting to a fatal crash
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By: silent_assassin@btinternet.com

silent_assassin@btinternet.com — Thu, 13 Nov 2008 20:42:59 +0000

What normally happens is, when you reach a speed thats far to fast the aircraft starts to shake (bit like turbulance) then as the speed gets faster and faster the shaking becomes more violent. When it gets to this stage you need to slow the hell down (idle throttles, little bit of flap and try to climb a little bit) the speed should drop rapidly. When you are at a safe speed again, then retract the flaps and set the nose on the horizon indicator and increase your throttle to about 50-60% to get a nice cruise speed. If you start to stall at all, then don't panic just open the throttle, retract the flaps and go into a very very shallow desent.
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By: mike b

mike b — Thu, 13 Nov 2008 20:05:59 +0000

you could rip the wings off
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By: helipilot212

helipilot212 — Thu, 13 Nov 2008 19:48:59 +0000

Drag increases with the square of the velocity. Exceeding the VNE of an aircraft MAY do permanant deformation to structures and MAY result in a catastrophic failure. Most aircraft have about a 25-50% margin of safety on such things as VNE.
But if you came back with an airplane that had exceeded a 150kt VNE by 65kts…..I wouldn't fly it until it was throroughly examined and even then i'd be trepidatious
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Pilot..ATPL – Helicopter and Fixed wing

By: Ram

Ram — Thu, 13 Nov 2008 19:34:59 +0000

Redlining usually applies to the engine speed, not airspeed.

Abuse of the engine will lead to engine failure.

However, overspeed in an airplane can be catastrophic as well.
The stress induced by the air on the airplane will literally tear it apart.

Remember that aerodynamic resistancce goes up faster as you go faster!

So the difference between 110 and 100 far exceeds the difference between 50 and 40.

Hope that helps
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By: aedesign

aedesign — Thu, 13 Nov 2008 18:55:59 +0000

You could cause permanent deformation of the airplane structure, and/or propeller (and subsequently, engine).

At velocities up to and beyond Vne, the aircraft's wings are producing a lot of lift. So much so, that they could actually cause the wing structure to permanently deform. Even if they do not deform, it will cause a great deal of damage in terms of fatigue life.

That is why they say you can only fly in the "yellow" arc in smooth air. The wings are producing a lot of lift, and if you hit some turbulence that increases your angle of attack, you could easily produce so much lift that the wing structure will deform.

At that great of a speed, you will also be causing a huge stress-load on the propeller. Since the prop is fixed to the engine, you will also be over-stressing the engine. At your example speed of 215 knots, you would surely cause permanent damage to the prop and engine (assuming a fixed pitch prop).
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