This topic is open to collect technical opinions, publications, achievements and suggestions on this rather exciting aeronautical theme:
better known as:
* ADAV (vertical take-off and landing aircraft)
* VTOL (vertical take off and landing)
To give you a quick overview of the subject:
* planes are the most efficient in cruises; they fly much faster than helicopters with less energy expenditure
but they require long take-off/landing runways and do not hover
* Helicopters are the most efficient in manoeuvres, they take off from a reduced surface, can hover, make "chip jumps".
but they are fuel sinks and don't fly as well (in speed) and require mechanically very complex rotors.
Aeronautical engineers have been working on the subject for a long time, with more or less success: here is a small anthology and state of the prior art
* ADAV: French wiki
* VTOL: english wiki
recently the multirotor drones (often quadri) make the sector rebound, in particular by the electronic control of the device and the electric motorization, but they inherently have the defects of the helicopter (except that of the complex monorotor).
A first important question to ask in the design of a convertible aircraft is: where should the propellers be placed in airplane mode?
beforehand they should not be placed at the tail of the aircraft because there is a lot of turbulence there and the propeller works poorly there.
* at the wingtip?
* in the middle of the wing?
* on the nose ?
In an ADAV/VTOL, the question of placing rotors on the wings is serious, because by rotation of their axis of thrust, they will become thrusters in airplane mode.
And as Macro rightly said...
Macro wrote:Moving the propellers away from each other and from the body of the aircraft should probably limit the phenomena of disturbances of the airflows in suction of the said propellers. In addition (noted on my son's self-made four-engine drone) with the lever arm increases the maneuvering precision of the machine increases, but its reactivity (liveliness to change direction) decreases it is a story of compromise (from the moment the flows are no longer disturbed) if the beams are lengthened too much, the weight increases, the machine is more precise to stabilize but less reactive and loses load capacity, assuming that we keep the same management (case of my kid's drone) of engine regulation
Looking forward to reading you.