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Hans S

Fly by wire?

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There's lots of tinkerers, Long-ez strakes on a Cozy, forward hing canopy, air conditioning, retractable gear, not to mention the vast amount of unstock engine configurations.

 

There's a whole EFI group out there building fuel injections for everything, hit and miss til it works. I'm not one of those, but I find the idea interesting. I like to learn things even if I don't plan on using them.

 

**Long-ez strakes on a Cozy----I think you meant "Longer strakes on a Cozy. In this case. Cozy guys are looking for some more elbow room in a sort of cramped cockpit. I like the idea of the wider canopy myself.

 

**Forward hinge canopy: There are all kinds of things that people are trying to do with this---mostly keeping the canopy closed in flight---not sure about the getting out part.

 

**Airconditioning---it is hot in the cockpit in the summer while taxiing around. Most think this is a waste of time---one guy has it as a requirement to satisfy his spouse (either its cool or no plane----sounds like a requirement to me).

 

**Retract gear: people want to go fast---I think it is a red herring---and introduces a whole lot of minuses---but whatever. Mostly it looks cool

 

**Unstock engines: People are hoping for cheaper alternatives than our Lycosaurs

 

**"nonstock" fuel injection---people looking for better engine performance---and at a cheap price.

 

**FBW on an EZ---you got me---don't get it---not sure what we are solving. The planes fly great and are reliable. Maybe you are looking for an autopilot---I get that part. There are all kinds of things that you could do on a homebuilt autopilot that would be truely useful and much safer to develop.

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Disclamer: I have no intention to do a FBW setup.

 

Some advantages/or not of a FBW as I see it. No particular order.

 

1. Stability Augmentation

2. Fly with a Game Pad controller. Like Nintendo.

3. Autopilot

4. Different capabilities for different flyers. slow controls compared to, "snap" it's there

5. Switch for which side is flying. Pilot/Co-pilot cut-out.

6. No need for hard mounted joysticks/armrests. More room. Fold away armrests, thinner.

7. Unplug and put away.

8. How's someone gonna steal it with no controls? Pad/joystick double as key.

9. Long enough cord or jack in the back for back seat flying.

10. Something different.

11. No linkage in plane to be in the way, snag, or become wiggly.

12. Makes wing removal quicker, just disconnect a plug. Ease of cramming more planes into a single hangar.

13. Automatic take-over if someone tries to do something beyond the planes capability.

14. Future big brother: implement to main control so tower takes over and keeps you in pattern.

15. Reads bios, if you are out-cold (sleep, heart attack, too high no O2) plane takes over and can be landed remotely.

16. Actuation could be electro-Hydraulic or all electric stepper motors.

17. Weight and redundancy? It was pointed out we don't fly large planes, how heavy would the primary and secondary system actually need to be? What does the hydraulic speed brake actuator weigh? Could be controlled using a laptop/tablet which has all the other engine and flying goodies in it.

18. System self-diagnoses. If one actuator goes bad, or both primary and back-up go bad on a surface, system automatically tries to compensate using other surfaces for balance.

19. The software is pretty much there with the simulator software already available.

 

Again, I have never worked on a FBW. This was a curiosity more than anything else.

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I guess it goes under stability augmentation but the list shoud include improved pilot ability to control an inherently unstable aircraft.

 

Also I would definitely consider a mechanical linkage as one of the redundant systems in this thought experiment.

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Also I would definitely consider a mechanical linkage as one of the redundant systems in this thought experiment.

Probably, if you lost your electrical or popped a breaker/fuse, it could be a tad bit stressful. Goes back to the redundancy issue. When is it enough. Of course, the current system works too and has for quite a while.

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15. Reads bios, if you are out-cold (sleep, heart attack, too high no O2) plane takes over and can be landed remotely.

Just imagine the kids with a notebook in the back seat: "Your computer has found a new device [COZY IV], press 'enter' to configure"...

 

I believe the US Department of Ultra-Nationalistic Fervour is pushing for a similar device for airliners.

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<snip--with comments>

 

1. Stability Augmentation-----this is probably one of the main reasons for FBW in aircraft----none needed in EZs

2. Fly with a Game Pad controller. Like Nintendo.----ok

3. Autopilot-----not sure I get this. Most of the FBW systems that I am familiar with have a separate autopilot

4. Different capabilities for different flyers. slow controls compared to, "snap" it's there----ok---but when you have added a FBW system to remove weight and complexity in the aircraft (not applicable here), you can then get the added benefit of taming some of the flight regime over a very large operating envelope---very fast to very slow. All the Ezs have a very small operating range----and if the controls were too slow or too quick, you would be in the wrong aircraft.

5. Switch for which side is flying. Pilot/Co-pilot cut-out.-----An Infinity stick can be switched by the pilot to isolate all the buttons on the other stick without using FBW---which is really the issue when you have a newbie flying and hitting the buttons on the stick that you don't want him to touch. The simpler solution in a Cozy is to slap the guy next to you and tell him to get off the stick. For those with a guy in back---shake to take, push to pass.

6. No need for hard mounted joysticks/armrests. More room. Fold away armrests, thinner.----You will always want your armrest in both the Cozy and Longez---so making it foldable won't help. In my Cozy, the original builder made the armrests quite smaller to give extra "butt room." I can't imagine needing all that butt room---the real issue is around the shoulders and head. But the loss of much of the armrests also lost all my map storage that was supposed to be there.

7. Unplug and put away.-----ok---but as you look at this from a "systems approach"---is there a better way to solve this? Like a main battery disconnect in a location only known to you-----or some other feature that would disable the aircraft?

8. How's someone gonna steal it with no controls? Pad/joystick double as key.----yep, they won't be flying it out. Heard a story once of someone breaking into a Longez hangar and using a chainsaw to saw off the nose to that the instrument panel.

9. Long enough cord or jack in the back for back seat flying.

10. Something different.-----this is not a good reason to do it

11. No linkage in plane to be in the way, snag, or become wiggly.----yes (maybe)---but you trade those minor (and pretty much non-issue type problems) for more serious problems

12. Makes wing removal quicker, just disconnect a plug. Ease of cramming more planes into a single hangar.----Cozy and Longez flight control disconnects can be accomplished in 30 seconds---maybe a minute if someone distracts me. I would highly not recommend removing the wings to park---unless long term--like over the winter or something. From a systems approach, the flight control system is not the issue----it is the removal of several siliconed plates and 6 large bolts---some of which you need to be a little acrobatic to get to.

13. Automatic take-over if someone tries to do something beyond the planes capability.----ok

14. Future big brother: implement to main control so tower takes over and keeps you in pattern.----ok

15. Reads bios, if you are out-cold (sleep, heart attack, too high no O2) plane takes over and can be landed remotely.-----ok

16. Actuation could be electro-Hydraulic or all electric stepper motors.

17. Weight and redundancy? It was pointed out we don't fly large planes, how heavy would the primary and secondary system actually need to be? What does the hydraulic speed brake actuator weigh? Could be controlled using a laptop/tablet which has all the other engine and flying goodies in it.

18. System self-diagnoses. If one actuator goes bad, or both primary and back-up go bad on a surface, system automatically tries to compensate using other surfaces for balance.-----very true! But you just caused this problem by going to electric actuators and/or hydraulic to begin with. By the way, the software for that kind of system is very complex----also, on bigger aircraft, you have more control surfaces and engines to help compensate.

19. The software is pretty much there with the simulator software already available.----don't believe this is true---but not my expertise

 

<snip>

 

On a go-kart, I would never put in power steering. It may be cool, the latest thing, and different----and that is what all the big cars have so it must be good----but the fact of the matter is that the steering forces on a go-kart don't warrant using power-steering----not to mention the added complexity and weight.

 

I can just about guarantee you that an aircraft designer would have much rather gone to a full mech system---but he had way too many other problems to solve which made FBW look attractive. Our problems are way too small to make that jump---and get some of the side benefits that you mention.

 

The other thing you have to worry about on a hyd or FBW system is to make sure that you get some sort of feedback through the stick. Your stick needs to feel wiggly when really slow and tight when fast. You also need to pay attention to stickforce per G----if too light, you may easily overstress your aircraft.

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Hans,

You might post your ideas to the Canard (Marc's) Mailing list, if you want some feedback.:) There are a lot of very accomplished Canardians there and they might have input for you. Maybe you are getting responses via private messaging...don't know. I personally think you are way out there...but I'm not that experimental in my canard control goals...

...Me. Give me a couple of MGL Odyssey's and a trio autopilot, servos for pitch and roll trim, custom stick grips and I am good to go.

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Hans,

You might post your ideas to the Canard (Marc's) Mailing list, if you want some feedback.:) There are a lot of very accomplished Canardians there and they might have input for you. Maybe you are getting responses via private messaging...don't know. I personally think you are way out there...but I'm not that experimental in my canard control goals...

...Me. Give me a couple of MGL Odyssey's and a trio autopilot, servos for pitch and roll trim, custom stick grips and I am good to go.

Since it was mainly my curiosity about others innovations, I won't sleep over it either way.

 

Yes, people have emailed me off line, basicly in a nut shell, they have pointed me to look for "true" experimental sites.

 

As stated by an email I received (I left the name off);

"Canard Zone for the most part is very close minded. Most think that following a much used/followed plan and learning to do some fiberglass work puts them above others and puts them in the "experimental niche". Most do not want to learn anything about their plane other than it flies. Modifications, of any kind, are almost always attacked, with little thought of the potential benefit of new technology. Most of the innovators left this site a long time ago because of this. When they show up at Osh or RR it becomes a "wow", then people want to know how it was done so they can implement it also, this is after berating it to death when originally asked about on this forum. Quite honestly, there are way to many Devil's Advocates here. Good luck."

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Keep in mind that while you may have this in hand, others may be put in danger trying to impliment the same modification as a result of the untested theories that are published on the web.

 

Example: An inovator in the sky diving community came up with three modifications to the parachute container (pack) back in the late 70's.

 

One is still used today and was a significant advancement in safety. The other two resulted in many tragic fatalities and many more reserve parachute activations.

 

It's a bad when you only get enough time for only one 'Aw sh!t!'

 

Develop ........ test .......... THEN publish.

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What can I say to your post?

The majority of guys that ARE BUILDING canards are guys that want a fast plane that flys well and gets great performance per pound of fool put into it.

The vast minority of builders are out there to try something in between very experimental and minor customizing.

There are some who want to be on the edge.

When you have actually built for a year, and felt the effort of the work, which is substantial, and have 4 years left to finish..., maybe you will feel a bit different about turning it into a ''what if'', ''maybe this will work'' kind of airplane.

To put the spin on it that we are a bunch of curmudgeons without any vision here, is not real accurate. I guess you feel the guy's that you prefer to hang with are a cut above us. No problem. One chooses to listen, to one who agrees with oneself.

Good luck in such endeavors, ones survivability odds are at odds with some experimenters desires.

I will go on record as one who read your long list and felt it was frivolous invention of needs. But then MY invention of the Cozy Boys seats and slanted IP panel and other work has been met by some with raised eyebrows, so maybe you just gotta do what satifies YOU and its good.

Oh well, blame it on the curmudgeon in me.

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Since it was mainly my curiosity about others innovations, I won't sleep over it either way.

 

Yes, people have emailed me off line, basicly in a nut shell, they have pointed me to look for "true" experimental sites.

 

As stated by an email I received (I left the name off);

"Canard Zone for the most part is very close minded. Most think that following a much used/followed plan and learning to do some fiberglass work puts them above others and puts them in the "experimental niche". Most do not want to learn anything about their plane other than it flies. Modifications, of any kind, are almost always attacked, with little thought of the potential benefit of new technology. Most of the innovators left this site a long time ago because of this. When they show up at Osh or RR it becomes a "wow", then people want to know how it was done so they can implement it also, this is after berating it to death when originally asked about on this forum. Quite honestly, there are way to many Devil's Advocates here. Good luck."

I have read many times about Canardzone being closed minded----and the experimental "cert" should allow us to cert. How about these mods?:

-Want more fuel capacity---so lets just not put in that extra piece at the back of the strakes. Forget the guys at canardzone----who needs to know about CG? I am sure the plane will be stable.

-I want a new airfoil. Don't know anything about aerodynamics---but this is experimental right?

-I want to change the location of the canard and change its AOA---don't know anything about static and dynamic stability---or aerodynamics---but I am ok with that.

 

 

You need to realize when you are out of your realm and not go there.

 

There are MANY modifications within the average canard builders realm. On my Cozy--not built by me:

--unique canopy latch system---it is ok

--electric nose gear---I am 160 lbs, fly almost always solo up front----and the nose is way to hard to lift without electric nose gear---good mod

--electric pitch trim. On my Longez, the mech pitch trim was outstanding and easy to operate. The pitch stability was awesome. I could never quite trim the Cozy to where I wanted it with the mech system. The electric pitch trim is on the stick---and I can dial how fast it spins (slow for cruise and fast for in the pattern). Good mod.

--armrests thinner (giving up the map pockets) and the center armrest removed. Since no center armrest, no place for lever throttles---push pull only. Don't like the mod. Does not give you more room---unless you have a very wide butt----and I rather liked the levers in my Longez instead of the push pull cables in my Cozy.---bad mod

--underwing sumps removed ---sumps in R/C armrests. Aircraft also has the capability to feed off of both/ left/ or right. Good mod---I like it.

--experimental electronic ignition and fuel injection. I like it.

--"wing" fuel drains attached under the sumps which are in the armrest. Zero knobs sticking out of the plane. Cool idea---but I would have preferred the drains in the normal upfront position. With the plane parked on its nose, the water won't be collecting where my drains are. I have to stand it up and give it time to drain to the new low point. Don't like it that much.

--headrest not per plans---really opens up the aircraft between the front and back. However, without the copilot "triangle" there is no good place to mount a gas strut to give a nice firm closing pressure as well as to keep the canopy open. I do have a gas strut---just no down pressure---and due to geometry, even a little bit of wind will overpower my strut and slam down the canopy. Not a good mod

--Part of the "not sticking anything out in the windstream program", I have no step to get in. No a problem for me---but a lot of people have a difficult time getting in without it. I could use the electric nose gear to stand up the plane with people in it---but I don't.

--Landing and taxi light at the wingtip strakes---I love them

--electric speedbrake. With the armrest mods, the only thing left was electric speedbrakes. The bad news is that I could have a really bad day if it got stuck down----impossible with the mech system

 

Mods that I did not know about but found out later:

-stainless steel hardlines to the brakes. This was ok---but the ID was too small (smaller than plans) which severely limited the braking action. Took me a long time to find that brake problem.

-breather tube smaller than plans (caught that one right away). The builder did not---did an engine out landing when he blew his nose seal. His fix was to put in a "overpressure valve." The before and after mods were dangerous-and I immediately changed it out.

--nose gear upper attachment was modded with "ace hardware" type screws instead of the ones specified in the plans. I exceeded the shear strength of the installed screws while raising the gear on the ground with people aboard. It was not the one time raising---but several years of use. Installed the proper screws.

 

 

 

Mods I wish I had:

--Wider canopy

 

Frivolous mods:

--retract gear on EZs. 5K+ bucks, increase risk to your engine and spar (unless not mounted to the spar), lost gas, no gain in knots (compared to well faired gearlegs on an EZ). But hey, it looks cool!! The heavy iron guys don't put on retract gear to look cool---they actually need it.

--airconditioner. For the guy who has it----it was needed---I understand.

 

Best mods on my Longez that I did:

--Big engine (O320). More speed, lots more climb, shorter airports, higher ceiling, better carrying capacity----at the expense of more gals/hr. Absolutely loved it. This involved a reworked engine mount and a replacement of the upper extrusions. Joe P showed me how to remove the old upper extrusions and replace them with a larger vertical web---and how to match drill them. Dave R welded up the mount for me. I was out of my element here---and got lots of good advice from people who knew what they were doing.

--Downdraft cooling. I hated everything updraft about my Longez. Downdraft solved many many problem. GREAT mod!

--front mounted brakes. Did not even know I had a problem until I did this. Boy did the braking action get better! But I did this mod not for the great gain that I got, but the beefed up mount that I needed for the big engine did not permit the master cylinders to be mounted as per plans.

--aluminum instrument panel. Loved it.

 

What would you say if I were pursuing doing a movable droop nose cockpit so that I could see the runway better--like the Concord. Lots of weight, complexity, etc. I would say that I was a little strange putting a lot of effort to solve a problem that does not really exist. Sure---you are a lot more cocked up on landing than a Cessna---but to warrant upper end performance losses, etc. I guess the guys on the "other forum" would welcome me with open arms. But at least with my droop nose concept, I won't get myself killed----unlike some of the guys out there who are not engineers---but want to play one in real life.

 

One last comment. One thing I really like about my EZ is that it is reliable. The same was not true in the military aircraft I was flying. Those were VERY complex systems---that required lots of maint per flight hour. Be careful when you move from a real reliable system to one that is more complex. Same thought holds true with my electric speedbrake---but in that case, I never deploy it unless I intend to land.

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Canard Zone for the most part is very close minded.

I disagree with that. My impression is that there tends to be more "out there" discussions here than in the email forums, which tend to have more flyers.

 

Most of the innovators left this site a long time ago because of this. When they show up at Osh or RR it becomes a "wow", then people want to know how it was done so they can implement it also, this is after berating it to death when originally asked about on this forum.

Having read post after post here for many years, I have to call BS on this one. Give me just ONE example of someone who had a modification 'berated to death here' AND showed up at OSH or RR with their modification.

 

Innovators are here, reading, lurking, and building. They're building new and improved canards; just not flying cars.

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Hans, I have to agree with Jon. None of what is said below is directed at you, it is to hopefully explain the difference between topics that are relevant and those that are not goinghave a warm reception.

Also there is a difference between naive foolishness, brash ignorance and experimentation based on investigation and considered conclusions.

I would propose to you that some of those who may have told you that the Zone stifles creativity may have a stake in some other venue they are steering you to?

A little history might help...

There have been those who come in like children and take up a lot of bandwidth posing ideas that are absurd....

"Yeah I want to widen it some, about 14" so I can put an aisle down the middle so the pilot can get up and go back the toilet..."

We do get this kind of thing on the forums, the determined newbee is dead serious. How do you propose we address this. This is not T-Ball, everybody is not a winner and everbody does not go home with a trophy. It takes time to give a considered response but it does get a bit frustrating after awhile to back someone up that does not have plans yet and explain why they cannot do this or that.

Things you won't know, cannot know until you are into the teens of chapters is that deviations, changes and mods are the death of projects. You are on your own and there is no hotline to bail you out.

When people are adamant that you not start your project armed with a list of mods you are going to make, they are not trying to kill you dream. They are being compassionate and trying to get you started down a path that will assure your success and safety, not certain failure. Somewhere down the road someone may aquire your failed project, if you were not capable of following the plans, where else did you deviate, make changes or omissions?

 

I wish the only determining factor in accepting a ride in a plane was my confidence in the capabilities of the pilot, now that we have a lot of creative builders there is additional criteria to consider.

 

I am sure some are laughing at this because those that know Randi and I know what our plane is like; nothing is unchanged. Let us say that every change made has been done before in some manner, we gave it our own spin and integratd it. There is a huge price to pay for the smallest change. We keep telling our customers, build to plans, put a Lycoming in it, get it done as fast as you can. Is your dream to build a project forever possibly not finishing it or is your dream to fly a really cool plane you built yourself? Go to Rough River and tell me there is a plane there you would not be proud to own, any one of those will be the coolest plane on any ramp at any airport except maybe Rough River or Osh. People have done it in as little as 18 months.

I forget the gentlemans name but the finest Long-ez I ever saw was a newly completed strictly to the plans one, but it was, perfectly shaped, it just had that air about it that was precision in detail. That impressed me more than the others around it with all the nifty mods and goo-gahs. It may have taken longer to refine it to that level.

Some people may get a little impatient when a speculator comes on list and begins discussions that are too far removed from what people a little farther down the road know as reality.

Its not being supressive for example to say "fly by wire in an experimental aircraft is the dumbest idea I have ever heard" Thats pretty much the end of tha discussion unless someone says "hold on, is there anything we can take from FBW that might make a better wing leveler system?" ..thats within the realm of things feasable and safely done by an experimenter.

If you look into it you will find that a good EFIS system with autopilot is in effect a FBW system with mechanical redundancy :D

...Chrissi

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Edge and Chrissi and whoever else,

 

This is my point of discontent, and other's that have emailed me.

 

To say just to build and then modify if needed, what if I get the fuse completed then decide I want it wider? I end up basicly wasting that whole build time as I now have to basicly start from scratch. People have already widened them up tp 12", though I don't know if the King Kozy is actually flying yet, but 6" wider are. They have been down the road so they know better what to do. To just build to plans then go back and redo stuff that could have been built in originally is a waste of time and resources. I'm told by others that there are lots of engineers here and that they think these planes should be modified after built, or the second build. Is it common to measure once and cut twice or the other way around.

 

Even something fairly easy. Forward hinge canopy. I would you build it for side opening then modify it afterwards? It's been done and is easy enough to incorporate during the initial build. Why go back and take the old hinge out and redo the canopy for the added stresses in different areas.

 

I personally ask questions here to find out if someone else has done it and how it worked. As far as this thread about the FBW, it was a curiosity, there are a few sites addressing FBW for small planes, I was just wondering if someone here knew anything about it. I have no desire to use FBW, though it keeps being stated I do. Frivolous or not, I can see for someone else it could be advantagous to have this type of thing.

 

Anyway, I see no need for me to post anything here unless it directly pertains to the plans. Yeah yeah, I hear the clapping .

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Hans:

 

I have been silent while this has gone back and forth. Your last reply:

 

Anyway, I see no need for me to post anything here unless it directly pertains to the plans. Yeah yeah, I hear the clapping .

This statement kind of set me off. I guess the thing newbie's dont understand is all they have invested in this is a few key pad clicks. Most of us have 1,000's of hours invested in these projects and also a few keypad clicks. There are very few totally stock Cozy IV's and very few totally stock canards in general. It takes a long time when you change things. I have a forward hinging canopy, a remote fuel valve, custom rudder pedals and brake cylinders. I have a gull wing door to he turtle deck and I am probably not done yet I will probably do down draft cooling. Most of these mods are considered acceptable to most of the canard community. They took me a whole lot of time to figure out. Especially the fhc and the rudder pedals.

My tub and all through chapter 9 is bone stock. I think the main reason that a lot of the canard community bristles at a newbie and his strange new ideas is there lack of commitment. I dont care what you build or how you build it just dont call it a canard or a Cozy IV I plan on building and flying my project. I also want to be able to license it and insure it for a reasonable cost. Modifications to flying surfaces and fuselage changes that make the plane no longer a plans built but a total experimental falling out of the air endanger my project. That makes me bristle I have a lot of time and money invested in this project you have a few key strokes. Go build something then come back and tell me how easy it is to modify and change things. I am a journey man plane builder you are an apprentice expect to be treated as such. STeve Building on

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Hans,

Let me take a different tact specifically about FBW. If you had a joystick with its outputs going to a computer and then feed that thru a 2 axis autopilot (the yaw thing would probably be too hard)---that would probably be a safe and "cool" system to "play" with as long as you kept the mech system in place and had access to the "real" stick----like the cozy stick on the other side----or always flew with a safety pilot in the rear of a Longez----very much like the space shuttle simulator is rigged. I also flew similar systems like this as a student at the Naval Test Pilot School. We contracted services with a company that has a lear jet modified with the real controls on the left and the "computer-electric" controls on the right. The safety pilot could re-dial in the controls to simulate different flight characteristics as well as different stick or yoke configs (such as a non-movable stick like early F-16s). The Air Force has a similarly configured F-16-----variable flight controls in the front, and safety pilot in the rear.

 

I still see no safe way---nor real reason to do this as a full up round aircraft (play thing with safety pilot=yes (and in this config----not really true FBW). But if your looking for some additional things to do in the air, you could probably do that safely.

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If you look into it you will find that a good EFIS system with autopilot is in effect a FBW system with mechanical redundancy :D

...Chrissi

wow, I can't believe I read the whole thing. and Chrissi is right. coupling an auto pilot to the GPS or such is very much FBW. I have made many trips where all I do is sit there and monitor the flight and adjust the trim knobs on the autopilot. I made a flight where the autopilot /GPS was engaged at 100 feet to almost touch down at 50 feet. I could have made the takeoff and landing by using the autopilot trim knob if I wanted to. So I have wires connected to a device that is connected to the flight surfaces. so you could say it is FBW with a stick for back up.

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But Lynn, in spite of your post...YOU are STILL a curmudgeon, according to those who favor extensive modifications. You/we have no vision, no real sense of experimentation. Didn't you get that. Old buddy, YOU are stifling others, you just ARE...we all are.

Rubbish.

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i think lynn should give his #2 plane to the new kid ..lol

it could be a wonderfull 20 year build.

you could call it a

curmudgeon mark4

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But Lynn, in spite of your post...YOU are STILL a curmudgeon, according to those who favor extensive modifications. You/we have no vision, no real sense of experimentation. Didn't you get that. Old buddy, YOU are stifling others, you just ARE...we all are.

Rubbish.

I did not realize we had no real sense of experimention or vision. so the sweat while test flying is just because the heater was left on. now I understand why all the home built accidents I read about every day, those must be the guys from the other forums doing the real extensive mods.

planning mods is easy. building the mods is a bit more difficult. testing to many mods will turn you into a Curmudgeon for sure

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Thoughts on Digital Fly-By-Wire.

 

I've given this idea some brain time, just to see what the complexity would be;

 

In order to keep weight and cost down, I'd probably opt for dual redundancy

(as opposed to triple redundancy on commercial systems).

 

Any descrepencies between the two redundant systems would then need to be resolved by the pilot, (This is the purpose of the third sysstem in commercial systems)

 

Each system would require the following;

 

6 closed loop servo systems; 6 Actuators, 6 position sensors, 6 electronic drivers, input device(s), Attitude gyro sensor package, Pitot Static/Ram pressure sensor package, 1 CPU, FBY software.

 

 

 

ACTUATORS: 6 actuators, one for each aileron, one for each rudder, one for each elevator.

 

The actuators and electronic drive system need to be able to drive the flight controls to full deflection (one end stop to the other end stop) within one second, at full wind loading, say, 260 kts.

 

The actual forces (ft-lbs) that are required by the actuators will need to be computed along with any linkage geometry.

 

These could be similiar to high torque stepping motors driving an acme screw, that in turn is connected to the flight control surface.

 

FLIGHT CONTROL POSITION SENSORS: 6 Flight Control Position sensors, these tell the CPU the current position of the flight controls. The CPU then decides how much force ( based on attitude/airspeed) needs to be applied to the actuator to move it to the new commanded position.

 

ATTITUDE and PITOT sensors: Aircraft attitude, speed, and altitude need to be known in order to resolve flight control response issues.

 

i.e: Normally, the pilot cannot muster enough strength to move a rudder to its fully deployed position while cruising at 200kts. We may want to mimic this behavior in our FBY system.

 

The CPU and software need to be generated. This would be a very interesting project, Software needs extensive design, review, and testing.

 

 

EMI Hardning - Don't forget that everything needs to be hardened against EMI , i.e. lightning strike, flying near high power RF transmission towers (TV/Microwave transmitters)

 

*********************************************************************

 

IMHO - This would be a very interesting and challenging project thats within the capabilities of most modern Embedded CPU microcontroller systems. (No, I don't think it'll run on a PIC, but certianly a modern 80251)

 

If I were going to do this, I would find a Flying LongEZ and use it for the research and developement phase. Once it has about a gazillion trouble free hours on it, then I may think about installing it as a stand alone system in a new LongEZ.

 

Would I do this, no. The weight and complexity are overwhelming compared to the plans flight control system. BUT, It certianly is possible :-)

 

Waiter

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If you have ever worked with electronicly controlled servos systems you will know a few things; most have somewhere in them a comparitor circuit. This circuit looks at the balance between what the device is doing -VS- what the input or feedback is saying it should be. If either side of this circuit malfunctions in any way, the other side is going to keep driving until it either gets the balance feedback it is looking for or it hits the end stop. So even if you get a circuit to work and do what it is you want, the typical failure mode is unnacceptible. This is why components like our force trim for the pitch is designed so that you should be able to still fly the plane manually if the trim goes belly up or worse if it goes to the end stop.

For canard aircraft it would be ever so simple to put a linear actuator in as a substitute for the pushrod that goes across the firewall for the ailerons. This would reflex the ailerons up or down together. This would effectively reduce th need for excessive pitch trim at high speeds, would allow the ailerons to be slightly reflexed up in cruise for higher speeds, and for the adventurous, possibly rotate them down slightly (within the limits of the elevators to compensate) to act as flaps. Yes, so simple, somebody may have the faith in circuits and actuators to even try it. If it goes bad, it will kill you. From experience, I do not have faith in any circuit or component that would allow me to do this because I have seen the best circuits and best components designed by cost is no object companies and they still fail with great regularity.

What upsets me more than anything else here? Six, seven years ago I was on the other side of this argument. Nat's favorite epihet to shiney brand new wide eye'd newbies that wantd to widen his design or put bunk beds in the back, whatever, he'd preface everything with "first time builders... yad yada yada" and then to really drive them down he eventually added "that have never flown" or "do not have a license either". Noiw to me this came accross like he was describing something unpleasant on the bottom of his shoe and he would be very happy to get rid of it. In the last couple of years I find myself sounding more and more like Nat. Somebody PLEASE shoot me if I ever preface a reply with "First time builders" for I will surely have crossed the line.

 

So, my advice for would be builders :P is that you can learn a lot by listening and reading all the archives. Every question has already been asked and answered. As for this thread, I am moving on.

Hey Lynn, sorry about that last novel I wrote.

...Chrissi

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Hey Waiter: I've always wondered about the servos in FBW: how do you make them redundant? If one freezes up, then aren't you just eating up battery as 2 servos fight with the frozen one? To over come that, you need some sort of clutch, I guess, but I'm no mechanical engineer, I can't picture it.

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