Vehicle: Airplane: Landing
Hover Landing Gear   (+2)  [vote for, against]
VTOL Undercarriage for Non-Rolling Liftoff & Touchdown.

Fixed wing flight is the fastest way to travel across long distances, and is the most efficient form of flight, producing 10X the lift of rotors. But fixed wing flight requires a long runway for a long rolling takeoff and long rolling landing, in order to transition from standstill to flight velocity with sufficient lift, and vice-versa.

Instead of landing gear that's primarily designed to roll, we need landing gear whose primary purpose is to lift the fixed-wing aircraft off the ground to transition it to forward flight (and vice-versa, to transition it from forward flight to standstill on the ground)

We will use the usual combustion engine to power our usual fixed-wing forward flight, to travel from departure point to destination point. But we will use electric motors to power our hovering VTOL "landing gear", which consists of rotors. This is because electric power can more easily provide distributed power to multiple points on the aircraft, to help it hover for transition purposes. Electric power has low storage density, but we expect our takeoff & landing to be of brief duration, as contrasted with the longer duration of the forward flight travel from departure point to destination point, which will be done by standard fuel-powered combustion engine.

The electric power could be supplied by a dynamo/generator attached to our combustion engine shaft, supplemented by a not-too-heavy battery. Takeoff procedure would obviously require starting the main combustion engine to provide current to power the electric rotors.

The main transit portion of the flight would use a regular axially-aligned propeller driven by the combustion engine. But the rotors used for the takeoff & landing portions of the flight could themselves be cycloidal rotors. Cycloidal rotors are able to modify their thrust axis dynamically (see link)

Just as regular landing gear can be retracted into the body of the aircraft during transit, likewise these liftoff & touchdown rotors would also be retracted during transit.

Finally, even though this landing gear is not meant for rolling takeoffs or landings, it would have some small token wheels to facilitate ground towing. An aircraft so equipped would however typically be expected to hover out of or into its parking spot.
-- sanman, Sep 22 2024

Cycloidal Propellers https://www.youtube...watch?v=Io9N5IoIjcE
[sanman, Sep 22 2024]

Tail Sitter Aircraft https://www.google....zoAeJMw&sclient=img
Tail Sitters re-appear as a concept every now & then. Maybe it's time for the next round... [neutrinos_shadow, Sep 22 2024]

Light Fast Prop Aircraft https://youtu.be/NMckIYT35Yo
useful for test development [sanman, Sep 23 2024]

Cri Cri https://www.youtube...watch?v=knb3qNq-Uho
smallest twin-engine plane [sanman, Sep 23 2024]

Air One eVTOL https://www.youtube...watch?v=C6cecREUD0s
no combustion engine [sanman, Sep 23 2024]

SkyFly eVTOL https://www.youtube...watch?v=mstVqcT6T4k
[sanman, Sep 23 2024]

2 Modes of Takeoff for SkyFly https://youtu.be/1tIhvq5qmEY?t=553
(@ 9:14 pivots back on tail) [sanman, Sep 23 2024, last modified Sep 24 2024]

Fixed-wing Aircraft with Vertical Rotors https://youtu.be/TFxm1ChRL94
[sanman, Sep 23 2024]

Not a Zebedee spring, then?
-- pertinax, Sep 22 2024


Perhaps you could design the aircraft to take off and land on its tail, thereby eliminating the whole thing, or replacing it with a retractable tripod.
-- Voice, Sep 22 2024


How about separating the two? (Has been proposed before).
Obviously keep the capacity for a rolling take-off & landing, but an independent "vertical lift unit" that gets the plane to altitude & speed, then disconnects & flies back to the airport to pick up the next. Catching for landing would be more tricky, but if a rocket can land on a barge at sea, I don't think it's an insurmountable problem.
-- neutrinos_shadow, Sep 23 2024


@ neutrinos shadow: I used to think that Seaplanes were the most efficient way to go - especially for larger aircraft - because then you're just sliding across the water and don't need any undercarriage, plus lakes and oceans have lots of room for takeoffs and landings. But then I read that the hull reinforcement required adds too much weight penalty compared to regular hulls and landing gear.

But regarding your suggestion - maybe an air-hockey table instead of a runway?

Still, I'd like the idea of VTOL to lift off from anywhere and set down anywhere. I think ditching the wheels for VTOL rotors should make it doable -- just start out test development using a very lightweight minimalist fixed-wing airframe to make VTOL easier. Then over time you can eventually perhaps evolve to doing VTOL on bogger and heavier airframes.

See links for interesting small fixed-wing aircraft.
-- sanman, Sep 23 2024


@ Voice: See that link to video of SkyFly showing 2 Modes of Takeoff @ 9:14
-- sanman, Sep 23 2024



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