19 votes

Can we add treadmill-like structures over the airplane surfaces to reduce friction, decrease drag and producing energy?

You can't reduce friction with machines. The nature of machines is that everything you do adds inefficiency. A moveable wing surface adds weight, complexity, and additional losses. Even if you did it ...
Tiger Guy's user avatar
  • 6,803
9 votes

Can we add treadmill-like structures over the airplane surfaces to reduce friction, decrease drag and producing energy?

Can you reduce friction by making a surface frictionless? Yes. Will that reduce drag? Most of the drag comes from lift. Without lift, the airplane falls out of the sky. Most of the rest of the drag ...
david's user avatar
  • 733
6 votes

Can we add treadmill-like structures over the airplane surfaces to reduce friction, decrease drag and producing energy?

Let's be honest here... From an engineering point of view, this is totally impractical and could never work with anything like current technology. Consider that the surface of an aircraft is not a ...
rghome's user avatar
  • 161
5 votes

Why modern diesel engines have low compression ratio?

Diesel engines with turbos have a lower compression ratio. Also the compression ratio has been lowered generally to help reduce the nitrogen oxide emissions. The better fuel delivery control and spray ...
Solar Mike's user avatar
  • 15.6k
5 votes

Can we add treadmill-like structures over the airplane surfaces to reduce friction, decrease drag and producing energy?

Air on a wing or aileron or any airfoil does not slide on the surface of these, a very thin layer of air (boundary layer's contact surface) sticks to the surface and moves at the same speed as the ...
kamran's user avatar
  • 22.2k
2 votes

What is the impact of energy control in an AC in terms of cooling and power consumption?

Inverter ACs are more efficient because a compressor running all the time at 50% is more efficient than a compressor that runs at 100% half the time. This is because the 100% compressor has maximized ...
Tiger Guy's user avatar
  • 6,803
2 votes

Why modern diesel engines have low compression ratio?

For NA engines it was found that the extra thermodynamic efficiency was eaten up by the mechanical efficiency and pumping losses.
Greg Locock's user avatar
1 vote

How to calculate the optimum heat absorption rate of an object?

You face a complex problem and have three likely choices for the approach to solve it. The first is to do experiments on what you define as your measure of effectiveness versus flame size. Perhaps you ...
Jeffrey J Weimer's user avatar
1 vote

How to calculate the optimum heat absorption rate of an object?

You need to quantify both competing factors. This can be done empirically without too much difficulty. Determine the rate of heat loss from the water to the environment vs temperature. Simply start ...
Drew's user avatar
  • 1,931
1 vote

Can we add treadmill-like structures over the airplane surfaces to reduce friction, decrease drag and producing energy?

Unless the treadmills are independently powered, which they aren't according to your description, then they will only move if there is friction with the airflow to make them move. If we pretend there ...
Liamlah's user avatar
  • 11
1 vote
Accepted

What is the efficiency of Solar energy run turbines? Are they better or worse than Solar PV cells?

Less than 31.25% when going to electricity per wikipedia. (If you just needed heat for heating a room, it's a different story- 80% is not unheard of, but you'd be doing well to get half that into ...
Abel's user avatar
  • 1,333
1 vote
Accepted

What would be the efficiency of dielectric elastomers if these were made with copper wire instead?

Copper works hardens, then fractures. Don’t think this will last long.
Solar Mike's user avatar
  • 15.6k
1 vote

Do wind turbines placed on the sides of roads, powered by vehicles traversing the roads (traffic turbines) actually work?

I think that this idea will not result in an overall improvement in energy efficiency of human civilization. I have personally experienced, walking across and near a large road, that there is a wind ...
Kevin Reid's user avatar
1 vote

If it is more fuel efficient to mechanically inject gasoline into a high compression cylinder, why is it not done?

You are correct, and I apologize for the confusion. The auto-ignition temperature of gasoline is indeed higher than that of diesel [1]. I appreciate the opportunity to clarify and provide a revised ...
Todd Takala's user avatar
1 vote

If it is more fuel efficient to mechanically inject gasoline into a high compression cylinder, why is it not done?

First of all, a frame challenge. Saying that it isn't done is just wrong. Fuel economy in gasoline engines implies a big, sophisticated turbocharger installation. It works best with maximum volume, so ...
Phil Sweet's user avatar
  • 4,696
1 vote

If it is more fuel efficient to mechanically inject gasoline into a high compression cylinder, why is it not done?

Gasoline (Petrol) and Diesel are different fuels and perform best in different engines. Gasoline is best lit by a spark. Its autoignition is too imprecise to be used to start combustion. It would be ...
Tiger Guy's user avatar
  • 6,803

Only top scored, non community-wiki answers of a minimum length are eligible