Thrust to Weight Ratios

[titanic3]

Just a question that popped into my head the other day.

1. If a plane had engines capable of exceeding 1:1 thrust to weight ratio, does that mean they can simply point their nose 90 degrees up and climb without fear of stalling out? I would imagine that gravity and less dense air at higher altitudes would eventually cause the plane to stall out. But assume that the atmospheric conditions stays the same, would it still be able to go up and up?

2. Were there any planes during WWII that could do this? Besides the Me-163, because it is a manned rocket, not a real plane.

[Drano]

A five ounce bird could never carry a three pound coconut! It's a simple question of weight ratios!   

[curry1]

Just a question that popped into my head the other day.

1. If a plane had engines capable of exceeding 1:1 thrust to weight ratio, does that mean they can simply point their nose 90 degrees up and climb without fear of stalling out? I would imagine that gravity and less dense air at higher altitudes would eventually cause the plane to stall out. But assume that the atmospheric conditions stays the same, would it still be able to go up and up?

2. Were there any planes during WWII that could do this? Besides the Me-163, because it is a manned rocket, not a real plane.

1. Yes theoretically they could point their nose up and accelerate indefinitely except for the drop of engine performance at altitude.  So if the atmospheric conditions stayed the same, yes, it could go on forever.

2. No WWII plane could.  Thrust to weight ratio of 1:1 is pretty impressive and not all modern fighters have it.

[Karnak]

2. Were there any planes during WWII that could do this? Besides the Me-163, because it is a manned rocket, not a real plane.

Me163 cannot do that either.  Best sustained it can do is, IIRC, 70 degrees.

[titanic3]

1. Yes theoretically they could point their nose up and accelerate indefinitely except for the drop of engine performance at altitude.  So if the atmospheric conditions stayed the same, yes, it could go on forever.

2. No WWII plane could.  Thrust to weight ratio of 1:1 is pretty impressive and not all modern fighters have it.

Me163 cannot do that either.  Best sustained it can do is, IIRC, 70 degrees.

  Thanks for clearing it up guys.

[moot]

You don't need lift if your thrust overcomes gravity.

[titanic3]

You don't need lift if your thrust overcomes gravity.

This is slowly coming to me but...does that mean that:

1. Hot Air Balloons and blimps are able to "fly" because their LIFT overcomes gravity, but has no self-thrust, relying on wind/currents? (Or using small propellers/engines)

2. Rockets/Missiles have no lift, but has enough THRUST to "fly".

3. Airplanes produce both LIFT AND THRUST. Being the heaviest of them all.

[Karnak]

A fixed wing aircraft going straight up is not producing any lift.  It is relying just as much on pure thrust as a missile.

[moot]

Titanic it's only as complicated as it seems because that's the engineering challenge presented by beating gravity - making what you want from what you have, economically.  That means we can't just strap a Saturn V engine to anything.  It's why modern private planes are so light, IE efficient in lift compared to EG warbirds.

It always comes down to the net forces acting on any body.  To fly you have to somehow beat gravity.  Whether by throwing stuff out the back the way you'd throw a rock from a small raft on still water, or by moving thru air fast enough that you have a net upwards force from the air moving against the surfaces you designed to produce just that effect.

[hitech]

1. Yes theoretically they could point their nose up and accelerate indefinitely except for the drop of engine performance at altitude.  So if the atmospheric conditions stayed the same, yes, it could go on forever.

If it is a prop plane or helicopter, the thrust will drop off with vertical speed regardless of altitude.

Simple trivia/ physics question.

When a plane is in a steady state climb does it need more lift than if it is flying level?

HiTech

[FLS]

No. It paradoxically needs less lift since the thrust supports part of the weight.

[shdo]

The first modern jet to have a T/W > 1 was the F-15 Eagle.

shdo

[nrshida]

So it is unnecessary to push to zero G on the accelerometer in a vertical climb to reduce lift induced drag on the wings to nothing?

[FLS]

So it is unnecessary to push to zero G on the accelerometer in a vertical climb to reduce lift induced drag on the wings to nothing?

You're describing a zoom climb, not a steady state climb. Reducing drag is good but you need lift for a steady state climb.

[nrshida]

Let me rephrase the question then: will I zoom higher by pushing to Zero G or by leaving in on 1?