Fly-by-wire and gliders

We have not seen much performance increase with new gliders for couple of decades, other than increased wingloading. I wonder if anyone has run the numbers for glider with FBW steering. I'm thinking of flapped glider with multiple moving segments of flaps (independent servos) and very small rear fuselage/tail, possibly with only minimal elevator (like Genesis2). Designed stability would not be issues as FBW brain would keep nose pointed to where you want all the time, glider could be aerodynamically unstable like modern fighter. Rudder authority would not be issue as yaw could be partly controlled with outboard flaps acting as spoilers, possibly airbrakes could be done with flaps only, FBW would adjust for configuration changes. Probably rudder pedals could be "optional" as FBW could keep "yaw string" centered. No need for control lines or flap mixers. Power for FBW and servos would need few bigger lithium batteries.

I'm visioning glider flying into thermal, where you just press "auto-thermal" and enjoy scenery.

Auto-Thermal scenery would have been enjoyable yesterday, where the strongest lift was frequently towards the wall of granite.
Jim

On Thursday, October 30, 2014 12:20:10 PM UTC-5, krasw wrote:
We have not seen much performance increase with new gliders for couple of decades, other than increased wingloading. I wonder if anyone has run the numbers for glider with FBW steering. I'm thinking of flapped glider with multiple moving segments of flaps (independent servos) and very small rear fuselage/tail, possibly with only minimal elevator (like Genesis2). Designed stability would not be issues as FBW brain would keep nose pointed to where you want all the time, glider could be aerodynamically unstable like modern fighter. Rudder authority would not be issue as yaw could be partly controlled with outboard flaps acting as spoilers, possibly airbrakes could be done with flaps only, FBW would adjust for configuration changes. Probably rudder pedals could be "optional" as FBW could keep "yaw string" centered. No need for control lines or flap mixers. Power for FBW and servos would need few bigger lithium batteries.

I'm visioning glider flying into thermal, where you just press "auto-thermal" and enjoy scenery.

I would hazard a guess that you haven't flown an older ship against a newer ship if you believe that the only difference is wing loading. The older airfoils "went to worms" with rain or bugs, or if you pulled a wee bit too hard in the thermal.

FBW is not going to boost glider performance. Glider performance comes from laminar flow and lack of separated flow much more than from reduced stability and a computer working to keep you pointed where you think you want to go.

And, there are certain sailplanes that already let you sit back and enjoy the scenery while thermalling. And they don't require FBW. Unless you consider the 7 x 19 cables that are hooked from the control surfaces to the pilot input devices. :-)

Just my two cents worth.

Steve

On 10/30/2014 1:20 PM, krasw wrote:

I'm visioning glider flying into thermal, where you just press "auto-thermal" and enjoy scenery.


Is that what you really want? Whats the point? Why not just pop in a
National Geographic blu-ray on your 80" plasma and enjoy the scenery on
the couch?

Luke

On Thursday, October 30, 2014 12:20:10 PM UTC-5, krasw wrote:
We have not seen much performance increase with new gliders for couple of decades, other than increased wingloading. I wonder if anyone has run the numbers for glider with FBW steering. I'm thinking of flapped glider with multiple moving segments of flaps (independent servos) and very small rear fuselage/tail, possibly with only minimal elevator (like Genesis2). Designed stability would not be issues as FBW brain would keep nose pointed to where you want all the time, glider could be aerodynamically unstable like modern fighter. Rudder authority would not be issue as yaw could be partly controlled with outboard flaps acting as spoilers, possibly airbrakes could be done with flaps only, FBW would adjust for configuration changes. Probably rudder pedals could be "optional" as FBW could keep "yaw string" centered. No need for control lines or flap mixers. Power for FBW and servos would need few bigger lithium batteries.

I'm visioning glider flying into thermal, where you just press "auto-thermal" and enjoy scenery.

Windward has at least one Duckhawk flying with auto-flaps...

Condor?

Ernst

I have worked with "Freedom's Wings International" for a few years now...(Flying for Pilots with Disabilities.)

Our gliders are fitted with "hand control" for rudder. The problem arises that the pilot must let go of the rudder control, to deploy the spoilers.....the spoilers are "notched" so they stay put, and the pilot goes back to rudder quickly....but a change in spoiler setting repeats the process...

After seeing a Duckhawk with electric flaps, and electric landing gear...I figured it would be nice to configure a glider with electric spoilers....Then there would be no need to take the hand off the rudder control....just push a button, or slide switch or whatever!

Of course radio controlled model gliders have everything fly by wire!


Cookie

One of the main issues with FBW is that there is relatively little in the way of off-the-shelf components of the right size and power to build the control systems out of. What OTS components are available from the world of sailplane-sized UAVs tend to be priced commensurately the low volume and specialized applications for which they were designed--which is to say, really freakin' expensive.

If somebody wants to jump into the market and make a line of high-reliability, low-power, servos and sensors and such, along with a networked FMS to run it all, I'm sure they could build it into quite a business in ten or twenty years or so.

While I am not looking forward for any automatic controls, I agree with the OP that FBW will significant improve performance. I believe the lost of performance due to inaccurate pilot input, un centered yaw string (heavy foot), non optimal flap position (I estimate I am flying in non optimal flap position maybe 30% of the time especially when doing a lot of transitions), flying too slow/too fast etc hurts performance more than the difference in glide performance between modern gliders.

Ramy

so... You want to eliminate all the things that make soaring challenging?

Dan Marotta

On 10/30/2014 6:04 PM, Ramy wrote:
While I am not looking forward for any automatic controls, I agree with the OP that FBW will significant improve performance. I believe the lost of performance due to inaccurate pilot input, un centered yaw string (heavy foot), non optimal flap position (I estimate I am flying in non optimal flap position maybe 30% of the time especially when doing a lot of transitions), flying too slow/too fast etc hurts performance more than the difference in glide performance between modern gliders.

Ramy