INTRODUCTION TO UNMANNED AERIAL SYSTEMS: APPLICATIONS AND REGULATIONS 4. What is

Question

INTRODUCTION TO UNMANNED AERIAL SYSTEMS: APPLICATIONS AND REGULATIONS

4.    What is Bernoulli’s equation and why does it matter to UAS

5.    How does size commonly cause a design difference between manned and unmanned aircraft?

8.    What are the benefits of a “conventional design” (conventional wing and tail)?

9.    What is meant by “pusher” and “tractor” in the context of aircraft design?

10. What are some advantages and disadvantages of a flying wing?

11. Are large or small rotors generally more efficient?

12. What are the disadvantages of a helicopter over a multi-rotor?

13. What are the four strokes of the Otto cycle?

14. What are the benefits of a two-cycle engine?

15. What are the main components of a gas turbine engine?

16. What are some disadvantages of using a gas turbine on a UAV?

17. What is the difference between a fixed pitch and constant speed propeller?

18. What’s JATA and what can it be used for?

19. What are the basic requirements to get an FAA remote pilot certificate?

Explanation / Answer

4) Bernoulli’s equation:

Answer:

Bernoulli Equation. The Bernoulli Equation can be considered to be a statement of the conservation of energy principle appropriate for flowing fluids. The qualitative behavior that is usually labeled with the term "Bernoulli effect" is the lowering of fluid pressure in regions where the flow velocity is increased.

Bernoulli's principle is a seemingly counterintuitive statement about how the speed of a fluid relates to the pressure of the fluid. Many people feel like Bernoulli's principle shouldn't be correct, but this might be due to a misunderstanding about what Bernoulli's principle actually says. Bernoulli's principle states the following,

10)Answer:

Advantage is obvious: There is only one wing to build, no fuselage and no tail section. But this wing has now to fulfil a lot of other functions, now that fuselage and tail are missing. Unfortunately, the necessary compromises make for a long list of disadvantages:

11)Answer:

a few largerengines is generally more efficient than having more smaller engines.

13)Answer:

The power produced by the Otto cycle is the energy developed per unit of time. The Otto engines are called four-stroke engines. The intake stroke and compression stroke require one rotation of the engine crankshaft. The power stroke and exhaust strokerequire another rotation.

14)Answer:

benefits of a two-cycle engine:

Two-stroke engines have certain advantages. They produce more power and more compact than the four-stroke engine, and they are lightweight and less costly. On the other hand, some fuel gets wasted in a two-stroke engine, decreasing its efficiency.

In the case of two-stroke engines, for every two strokes of the piston inside the cylinder, one power stroke is produced. In four-stroke engines, power is produced once during four strokes of the piston. For the same size engine, the power produced by the two-stroke engine is more that the four-stroke engine. Ideally the power produced by the two-stroke engine is double that of the four-stroke engine, but in actual practice it is only about 30% more than four-stroke engine. Also, since the power produced by the two-stroke engine is higher, these engines are small and compact in size.

Since there are no valves in the two-stroke engine and only ports, they are cheaper and require less maintenance. With two-stroke engines, the torque produced on the crankshaft is more uniform because the power is produced during every alternate stroke of the piston.

1) When the inlet valve of the engine is opened for intake of the air-fuel mixture, the exhaust valve is also open. Although there is deflector between the inlet and exhaust areas of the engine, some fresh air-fuel mixture always escapes through the exhaust area. Thus part of the fuel that would have produced power goes wasted. This increases the fuel consumption and reduces the engine's overall efficiency.

2) The two-stroke engine does not operate with the same efficiency at different speeds. When the carburetor's throttle valve is partly opened, the air-fuel mixture taken inside the cylinder is not sufficient to drive out all the exhaust gases, leaving some of the exhaust gases inside the cylinder even during the combustion stroke. This causes non-uniform burning of the fuel and inconsistent efficiency at different speeds.

15)Answer:

The gas turbine is made up of the following components:

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