Aero modelling?

Question

Aero modelling is a very interesting hobby where you get a chance to fly your own air plane using remote control . However, aero modelling has its limitations and the plane a person usually flies and controls is not exactly the same as the real life plane.

The question I want to ask is, using the most sophiscated equipment available, eg, very accurate millers, cutters or even grinders, is it possible for us to construct a miniature version of a fighter aircraft to be used for aero modelling?

Can we create a miniature F16 or F15 aircraft that is exactly like the actual aircraft except in size? This craft should also be able to fly at Mach 2 and it should be able to manoveour well, like the actual fighter craft. It will also use fuel and it should be able to mid air refuel using a miniature mid air fuel tanker.

Of course, it is controlled by remote control by the user.

Answer 1

This is the same problem encounted by professional aerospace companies (Boeing, Lockheed Martin, NASA etc). They have a lot of trouble getting a scale model to accurately behave in the wind tunnel. The reason is as follows.

In aerospace science, there is a value called the "reynolds number", abbreviated Re.
Now, you can take a semester on the applications of this and why it is necessary. Just note that this value is very important in calculating the properties of airflow. This value is highly dependent on size, velocity, and viscosity ("thick - stickiness") of the airflow.

This is where we run into problems with constructing a small aircraft. To say it plainly, because this value is heavily dependent on the size of the aircraft, this value will be very different from what a large plane would experience. Additionally, since the velocity is tied into this number, Mach 2 on a scale model is not the same as Mach 2 on a larger model.

In order to accurately scale a model, you need to match both Reynolds numbers and Mach numbers. This is very difficult. This is why it is not possible to have an aero model completely act like the real thing, in scale.

Now, there are certain conditions where these huge companies have been able to accurately model scale aircraft. However, their wind tunnels utilize special gasses or employ cooling in order to accurately scale to the performance since this allows the testers to change the speed of sound in the wind tunnel air as well as the viscosity.

On top of this we must concern ourselves with the powerplant. There simply isn't anything small enough and strong enough to propel an object that fast with exception to maybe rockets.

Answer 2

There are people making jet powered model aircraft, however, making a scale of a modern fighter may be beyond the average aero modeller. Most modern fighters are unstable, and even with the fastest computers available, i would think it impossible to make them "fly by wire" due to the effect miniaturising would have on the aerodynamics.

You may be able to approximate the charactaristics though.

Mid air refueling is hard enough when you are up there, without having a tiny plane and having a boom operator help you out, so i doubt that would be acheivable.

Answer 3

Even beyond the safety, range, and vision limitations of a scale model, airfoils at a scale are not simply scaled down versions of the 1:1 image. Since the air molecules and airflow are still at 1:1, scale aircraft wings require corrections to overall form. Scale wind tunnel test craft often reflect this misshappen correction.

So if you are set on something literally being an exact scaled down version of the 1:1 object, the physics do not suppor this.

Answer 4

The only problem with these high performance models is the limitations of keeping visual contact with it and the control radio range. They have some very fast (200 + mph, but not Mach2) jet powered models and mostly they just fly circles because if they go in a straight line for 2 or 3 seconds they are out of sight. Pretty cool to watch but a VERY expensive hobby.

Answer 5

Anything's possible with the right amount of money. The technology to make something so sophisticated but on a miniature scale is economically unfeasable.

If they can, however, make, those miniature Mars rovers, a miniature F-16 is possible.

I suspect a miniature propulsion system is the biggest hurdle

Answer 6

haha mach 2 with a radio controlled model, are you crazy?? 200mph is the standard with jet powered models.. It wouldn't be logical to scale down an airplane and expect its speed to be the same anyway..

Answer 7

Are you on drugs buddy? LOL