> […] flying wing aircraft […] are aerodynamically unstable. They can't be flown by humans […]
RC flying wings are regularly flown by humans without any software in between the input and control surfaces.
RC flying wings are regularly flown by humans without any software in between the input and control surfaces.
It is fine if a fighter jet crashes when the electronics fail. Much less so for a passenger yet.
I certainly hope not.
It may be difficult to achieve the required flight characteristics without software augmentation in a flying wing, even if RC hobbyists can usually fly them manually without crashing. The 737 MAX has raised the question of whether it's a good idea to approve transport category aircraft that require help from software to have acceptable flight characteristics.
MCAS (or another means to accomplish the same goal) was required for the aircraft to meet certification requirements, regardless of whether it was to share a common type rating with the rest of the 737 fleet (so long as it shared the landing gear with the rest of the 73' line, it was going to have this adverse aerodynamic raw result).
> 75 percent of maximum continuous power for reciprocating engines or the maximum power or thrust selected by the applicant as an operating limitation for use during climb for turbine engines; and
Wouldn't that give a stable pitch response because the thrust relative to the center of mass is constant? Also if the MCAS is always pushing the plane out of the given AoA (which seems to be what it's logic is, if AoA > x trim down until AoA < x) would that be considered outside the flight envelope anyways? The stick force curve goes screwy for every aircraft in a stall.
Technically this is definitely not true. Any modern RC wing will use software to do elevon mixing and get elevator/aileron input into the actual mechanical surfaces. It's possible to do this mechanically but software is so much simpler it's a no brainer to just have a servo per surface and do everything else in software.
It may be true in the spirit of this discussion in the sense that most RC wings just do fixed software mappings between inputs and outputs instead of having an on-board computer taking into account attitude/airspeed/etc and adjusting the inputs based on this. That's what's actually needed for aerodynamically unstable aircraft and RC wings generally don't need that, although similar kinds of hardware do exist in the RC world and are used sometimes.
The relevant question is whether there is an IMU providing feedback without which the plane would not fly.
[1] http://ardupilot.org/copter/docs/common-choosing-a-flight-co...
What kind of observations do you have to support your statement?
Ps. Most of them I have seen, and built, has been to play a game where you put a string on your tail and try to cut each others with the propeller. They were airodynamic stable.
However in RC gliders (slope especially) it's not necessary - the plane is made of foam and will bounce off any obstacle with minor damage, and they don't fly at long range. It's quite uncommon in this type of flying.
I've flown flying wing gliders that didn't have a flight controller - they work just fine. They're very aerobatic, though, which is less than ideal for carrying passengers.
The main issue I can see with this flying configuration is that the Centre of Gravity is extremely sensitive. You have quite a lot of leeway with a conventional airframe, but with a flying wing the CoG has to be spot-on or it becomes uncontrollable.
If your reference is simple foam planes this is true. But in high-performance applications like F3F people will run on-board accelerometer based control units that stabilize flight.
The whole discussion is a bit silly though. The standard for toys is clearly not the same as for a passenger carrying commercial airliner, even if sometimes they are very expensive toys...
> "everybody" puts a flight controller between the servos and the receiver these days
This was the point I was trying to address. It's definitely commonplace, but not essential, and the plane is aerodynamically stable without one.
As you might imagine, the scale and operating requirements of _actual_ aircraft introduces complex engineering challenges that aren't present in toys.