New answers tagged ultralight
3
Centrifugal clutches are mainly used to provide a compliant connection between the engine and prop to absorb power pulse peaks, as well as allow the engine to be automatically disconnected from the drive system at idle.
The big bugaboo of reduction drives over the years has always been torsional resonance resulting from the flywheel - the prop - being ...
2
In addition to xxavier's answer, a clutch makes it easier to maually start the engine (without the prop load) and easier to idle (for the same reason). There is also a safety benefit as well:
If you have ever seen a video of someone desperately hanging on to a groundlooping Piper Cub that was hand started with the prop, at too high a throttle setting, you'...
2
If I remember correctly, the 4-stroke Rotax engines include a sliding clutch to protect the crankshaft from shocks in case the prop accidentally contacts the ground.
0
The main point is to maximize the thrust that can be attained with the power available. Having a given power delivered by the engine at at given angular velocity, you should match that angular velocity to an optimum propeller. Thrust is obtained by accelerating a mass of air, and that's precisely the rôle of the propeller. Imagine you have a propeller that ...
1
An airplane uses propeller pitch change to achieve the effect of changing gears.
Engine RPM is held constant, the pitch of the propeller is used to take a bigger bite of the air with each revolution, loading down the engine more the same as changing gears does on a car or motorcycle.
So the question becomes: Is it worth the weight to make the prop pitch ...
1
A gearbox is not a useful addition. Some aircraft have geared propellers, but that's a single, fixed gear.
The engine has to be able to turn the propeller when it's in the highest gear you'll use, so that determines how much power is required.
In a car or motorcycle, the lower gears are used to match engine speed to wheel speed, allowing the vehicle to ...
1
The best suggestion I could give you is to abandon your project. There are no realistic consideratoins in it.
The engines you planned to use are just 10 Hp. These are moped engines and they generate their maixum power at lower RPM's. These engines are designed to operate at ground level, wherein majority part of these engines are run at low RPM's and at ...
6
You will need a fixed landing gear and a braced wing to keep your mass at your target of 40 kg. Expect a maximum L/D of not more than 10, maybe even 8.
You say that the flight mass will be 100 kg. The weight will be 980 N. 1/10 of that is 98 N. To arrive at a power from that will need a few more heroic assumptions. Your wing loading is probably 12 to 15 kg/...
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This has been done, but here are some things you'll need to consider.
Air-cooled motorcycle engines are designed to produce short bursts of peak power, and to be as light as possible. Lightness is an advantage for any airplane engine, but having an engine designed for brief bursts of high power is not. An aircraft engine has to operate for long periods at ...
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According to the manufacturer, it has a range of 1,300km.
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