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Author Topic: Mid engine canard  (Read 11467 times)

Offline Wolfgang Nieuwkamp

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Mid engine canard
« on: August 31, 2016, 03:00:45 PM »
Own design, electric mid motor.

As long as the motor runs, see video  [url]http://myalbum.com/album/pygoyWSQBOZ9/url]

But when gliding, the canard stalls.
Comments welcome,

Wolfgang


Offline Tim Wescott

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Re: Mid engine canard
« Reply #1 on: August 31, 2016, 04:24:58 PM »
Picture?  Show the glide?

What leads you to believe that the canard stalls rather than believing that the thing doesn't just have a normal pitch-down on loss of power?
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Offline Matt Spencer

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Re: Mid engine canard
« Reply #2 on: August 31, 2016, 06:49:46 PM »
But Canards CANT stall .  ;D

Online Brett Buck

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Re: Mid engine canard
« Reply #3 on: August 31, 2016, 08:28:00 PM »
But Canards CANT stall .  ;D

   Huh?  Magic relieves you of the laws of physics when the smaller wing goes first?

   Brett

Online Brett Buck

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Re: Mid engine canard
« Reply #4 on: August 31, 2016, 08:32:44 PM »
Own design, electric mid motor.

As long as the motor runs, see video  [url]http://myalbum.com/album/pygoyWSQBOZ9/url]

But when gliding, the canard stalls.
Comments welcome,

  I really couldn't make much useful out of the video, aside from you needing to do something about the engine, it sounds rather dire!

     Brett

Offline Wolfgang Nieuwkamp

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Re: Mid engine canard
« Reply #5 on: September 01, 2016, 07:08:11 AM »
The gliding angle is about 15°, even with full up (elevator 45" down). That convinces me that the canard is stalled (not the wing!).
As long as the canard is in the propeller slipstream, it is effective.

The strange motor sound during level flight is caused by ny motor speed regulating system. The accelleration sensor based system tries to keep the line tension (more corruptly: the centripetal acceleration) at around 3g. If too low, the speed is increased a little. Next measured after 8 ms, If too high, the speed is decreased with the same amount. Tim, this is an integrating regulation, correct?

The video was taken using a 2 blade propeller, with a 3 blade one the sound is much more pleasant.

Hope the picture will show:
[img]http://myalbum.com/photo/FfAQjYtkqi9v/1k0.jpg/img]

Thanks for the comments,

Wolfgang



 

Offline Tim Wescott

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Re: Mid engine canard
« Reply #6 on: September 01, 2016, 09:34:25 AM »
   Huh?  Magic relieves you of the laws of physics when the smaller wing goes first?

   Brett

Section IV, subsection 37, paragraph (A), Unusual Planforms, of International Standards for Model Aviation Aerodynamic Analysis clearly states:

"Aircraft that do not conform to the usual monoplane layout, with a single main lifting surface ahead of a single, smaller stabilizing surface, may be analyzed using magical thinking, as long as you can make it sound convincing. This rule specifically applies in the case of biplanes and other multiplane lifting surfaces, flying wings, 'flying lawnmowers', asymmetrical aircraft, and canards." (my emphasis)

There.  Now you know.

The gliding angle is about 15°, even with full up (elevator 45" down). That convinces me that the canard is stalled (not the wing!).
As long as the canard is in the propeller slipstream, it is effective.

So the prop is ahead of the stabilizer.  Could you please post some pictures?

Just because the shallowest glide angle is steep doesn't mean the canard is stalled -- it just means that it's generating insufficient lift for the conditions.  Have you tried moving the CG back?  I assume this is going to be an interesting balancing act, as having the elevator so close behind the prop is going to really crank up the sensitivity when the motor is running.

The strange motor sound during level flight is caused by ny motor speed regulating system. The accelleration sensor based system tries to keep the line tension (more corruptly: the centripetal acceleration) at around 3g. If too low, the speed is increased a little. Next measured after 8 ms, If too high, the speed is decreased with the same amount. Tim, this is an integrating regulation, correct?


If the increment is constant then it's sorta-kinda integrating control.  True integrating control would have you calculate the throttle as:

<throttle now> = <last throttle> + <integrator  gain>(<target accelerometer> - <accelerometer reading>)

If you have what I think you have it'll adjust slower than it could for large speed errors, and it'll always oscillate around the correct value instead of settling in to a constant value.  For a large enough increment the constant seeking of the throttle will cause the system to consume more power than if it settled out to a fairly constant value, but that effect may be washed out by the necessary throttle changes in response to maneuvering.

Given the various lags in the system, I expect that you could get snappier control with a proportional-integral controller, but if you do that then tuning will almost certainly be harder than with integrator-only control (and based on the tuning parameters that Igor exposes on his system, I suspect that's not what he does).
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The problem with electric is that once you get the smoke generator and sound system installed, the plane is too heavy.

Offline john e. holliday

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Re: Mid engine canard
« Reply #7 on: September 01, 2016, 11:28:46 AM »
Several years ago I built Richard Sarpolous Blue Goose canard to prove to some individuals that they were not thinking straight.   First flights took some getting used to with tail out front.  It was also sensitive to the controls as he showed them.   I putt longer control horns on and added nose weight.   I have a witness that has seen me put it through several AMA patterns when the air and engine run were right.   It landed like a dream.   

So I thought I could improve on it by building a Ringmaster variant.  I left off the trailing moving surfaces on the main wing.   Only the forward elevators move.  Draw back is there is no air going over the surface to keep the nose up.  Will correct that with a skid as it is still a little sensitive.  I have witnesses to this as it will go okay if hand launched.  It lands okay also if you keep the speed up on landing.   So far it has not stalled like I think a plane stalls by dropping the nose.   It will not glide like a normal stunt plane, but is a lot of fun to fly.
I was always taught to respect my elders, but it keeps getting harder to find one.
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Offline Wolfgang Nieuwkamp

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Re: Mid engine canard
« Reply #8 on: September 01, 2016, 12:14:16 PM »
John,

many years ago I also built a similar canard, and it did fly well, powered by a Fox 45.
Built a similar one, with electric power, but could not get it stable. So I tried an original layout, with a mid engine.

Tim,

a nice article on aircraft with 2 lifting surfaces can be found in    http://soartech-aero.com/SoarTech-6.pdf   on page 100 ff. I used Fraserīs reasoning for my layout. The pdf of Fraserīs article was too large to upload…..
The algorithm you suggested is somewhat difficult to implement in my old microprocessor, Microchip 12f675, but thanks anyway.

Hope the attached picture now shows.

Regards,

Wolfgang

Offline Tim Wescott

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Re: Mid engine canard
« Reply #9 on: September 01, 2016, 12:40:23 PM »
Tim,

a nice article on aircraft with 2 lifting surfaces can be found in    http://soartech-aero.com/SoarTech-6.pdf   on page 100 ff. I used Fraserīs reasoning for my layout. The pdf of Fraserīs article was too large to upload…..
The algorithm you suggested is somewhat difficult to implement in my old microprocessor, Microchip 12f675, but thanks anyway.

Hope the attached picture now shows.

Regards,

Wolfgang

Aw c'mon.  It's got 35 easy-to-use instructions.  And doing math in assembly is fun.  If you're sampling at 125Hz there should be plenty of time to do the calculation.  I'd implement the integrator gain with a shift -- trying to do multiplies on that chip would be a bear, and changing gains by factors of two usually gets you in the ball park.  If you want to get more precise, you can multiply by any factor of 2 times 1, 1.25, 1.5 or 1.785 with just shifts and either one add or subtract.

I'm not arguing with the layout -- just saying you should try moving the CG back and see how it glides.
AMA 64232

The problem with electric is that once you get the smoke generator and sound system installed, the plane is too heavy.

Offline Wolfgang Nieuwkamp

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Re: Mid engine canard
« Reply #10 on: September 01, 2016, 01:24:25 PM »
Tim, where can I find more assembler tricks? Multiply/divide by multiples of 2 is already used, but the other factors are new to me.

Regarding the CG, I will make a new firewall as far back as possible, around 7 cm back-
I am also considering to use a slotted flap elevator, but that will be a winter project.

Offline Wolfgang Nieuwkamp

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Re: Mid engine canard
« Reply #11 on: September 01, 2016, 01:25:57 PM »
Tim, where can I find more assembler tricks? Multiply/divide by multiples of 2 is already used, but the other factors are new to me.

Regarding the CG, I will make a new firewall as far back as possible, around 7 cm back-
I am also considering to use a slotted flap elevator, but that will be a winter project.

Offline Tim Wescott

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Re: Mid engine canard
« Reply #12 on: September 01, 2016, 02:06:03 PM »
Tim, where can I find more assembler tricks? Multiply/divide by multiples of 2 is already used, but the other factors are new to me.

I can't remember the name of the method*, but it's based on the fact that when you subtract a number you generate a string of ones:

In C-ish pseudocode:

0.75 = 1 - 0.25 (y = x - (x >> 2));
0.875 = 1 - 0.125 (y = x - (x >> 3));
1 = 1
1.125 = 1 + 0.125 (y = x + (x >> 3));
1.25 = 1 + 0.25 (y = x + (x >> 2));

Then you repeat, shifted up one:

1.5 = 2 - 0.5
1.75 = 2 - 0.25
2 = 2
2.25 = 2 + 0.25
2.5 = 2 + 0.5

Then

3, 3.5, 4, 5

Then

6, 7, 8, 10

Etc.

Multiplying by a fixed number is easy; if you want to have a user-configurable gain then you probably want to have some sort of a mantissa + shift arrangement (8-bit floating point!  Wow!) with the assembler equivalent of a switch statement for the four possible mantissas.

You could also stick to just 2 or 3 for the mantissa -- going in steps of 1, 1.5, 2, etc. is really good enough for most practical work.

* edit: Booth's Algorithm.  Here's the Wikipedia page
« Last Edit: September 01, 2016, 02:28:39 PM by Tim Wescott »
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The problem with electric is that once you get the smoke generator and sound system installed, the plane is too heavy.

Offline Wolfgang Nieuwkamp

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Re: Mid engine canard
« Reply #13 on: September 03, 2016, 09:49:57 AM »
Thanks for the algorithm. It would take a lot of space of the limited memory (and a lot of programming time), so I will stick to shift right/left…..

Offline john e. holliday

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Re: Mid engine canard
« Reply #14 on: September 03, 2016, 07:43:47 PM »
Now I remember why started skipping over some of the stuff the late-great Wild Bill Netzband used to write. 
I was always taught to respect my elders, but it keeps getting harder to find one.
Today I broke my personal record for most consecutive days lived.
John E. "DOC" Holliday
10421 West 56th Terrace
Shawnee, KANSAS  66203
AMA 23530

Offline Igor Burger

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Re: Mid engine canard
« Reply #15 on: September 06, 2016, 01:30:53 PM »

Given the various lags in the system, I expect that you could get snappier control with a proportional-integral controller, but if you do that then tuning will almost certainly be harder than with integrator-only control (and based on the tuning parameters that Igor exposes on his system, I suspect that's not what he does).

No, it is really not what I do :-) ... mine timer is feed forward, not feed back, so it is not PIDsomething at all :- )) ... simply it adds nose up and that is all :- ))

The biggest problem of such stuff is good tuning of proper filters, otherwise it reacts to improper things, for example if you try pull handle during flight, my algorithums calculationg "nose up" is confused and model will react by pulsing. But it will certainly not add power over head and so accelerate before descending - that is reason why it is not feedback system. It (PID) is not tunable if you do not have enough power (so it tends to wind up) and enough power will be too heavy. So it works only "somehow" - and that "somehow" is question of proper tuning :- )) so well working regulation is more about proper coefficients = hard work, not programming skill :- ))) ... I am programmer, so I did not have probles with it, anyway I spend 4 years testing until I tol myself "done".

I have here around 2 other friends trying do similar timers, but they still did not not get reliable feedback system fo far. I told them what they do wrong, but hard heads are hard heads :- ))))))))) 

Offline Tim Wescott

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Re: Mid engine canard
« Reply #16 on: September 06, 2016, 02:20:57 PM »
No, it is really not what I do :-) ... mine timer is feed forward, not feed back, so it is not PIDsomething at all :- )) ... simply it adds nose up and that is all :- ))

The biggest problem of such stuff is good tuning of proper filters, otherwise it reacts to improper things, for example if you try pull handle during flight, my algorithums calculationg "nose up" is confused and model will react by pulsing. But it will certainly not add power over head and so accelerate before descending - that is reason why it is not feedback system. It (PID) is not tunable if you do not have enough power (so it tends to wind up) and enough power will be too heavy. So it works only "somehow" - and that "somehow" is question of proper tuning :- )) so well working regulation is more about proper coefficients = hard work, not programming skill :- ))) ... I am programmer, so I did not have probles with it, anyway I spend 4 years testing until I tol myself "done".

I have here around 2 other friends trying do similar timers, but they still did not not get reliable feedback system fo far. I told them what they do wrong, but hard heads are hard heads :- ))))))))) 

The problem for the rest of us is that you're a programmer and a better pilot than almost any of us can hope to be.
AMA 64232

The problem with electric is that once you get the smoke generator and sound system installed, the plane is too heavy.

Offline Gerald Arana

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Re: Mid engine canard
« Reply #17 on: September 06, 2016, 03:00:06 PM »
John,

many years ago I also built a similar canard, and it did fly well, powered by a Fox 45.
Built a similar one, with electric power, but could not get it stable. So I tried an original layout, with a mid engine.

Tim,

a nice article on aircraft with 2 lifting surfaces can be found in    http://soartech-aero.com/SoarTech-6.pdf   on page 100 ff. I used Fraserīs reasoning for my layout. The pdf of Fraserīs article was too large to upload…..
The algorithm you suggested is somewhat difficult to implement in my old microprocessor, Microchip 12f675, but thanks anyway.

Hope the attached picture now shows.

Regards,

Wolfgang


Boy! You sure had me confused with that "Mid" motor comment! Now this post is starting to make sense!

Hey Doc, shouldn't your LO's be just behind the CG like a "normal" plane? Or actually in front of the LE?
Just asking, Jerry

Offline john e. holliday

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Re: Mid engine canard
« Reply #18 on: September 06, 2016, 04:26:18 PM »
The CG seems best if ahead of the main wing. 
I was always taught to respect my elders, but it keeps getting harder to find one.
Today I broke my personal record for most consecutive days lived.
John E. "DOC" Holliday
10421 West 56th Terrace
Shawnee, KANSAS  66203
AMA 23530

Offline Tim Wescott

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Re: Mid engine canard
« Reply #19 on: September 06, 2016, 05:17:27 PM »
The CG seems best if ahead of the main wing. 

Yup.  There's complicated math to figure out where the CG goes.  Then, there's Depron foam or 1/16" balsa with which to make gliders.  Wherever the CG goes to make it fly nice, it needs to be about 1/10 of a wing chord forward of that for a starting point, and then experiment and experiment some more.
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The problem with electric is that once you get the smoke generator and sound system installed, the plane is too heavy.

Offline Wolfgang Nieuwkamp

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Re: Mid engine canard
« Reply #20 on: September 07, 2016, 11:33:10 AM »
If you read the link,  http://soartech-aero.com/SoarTech-6.pdf  after page 100, you will find that it is easy to calculate  where the CG should be: Just 8% of the distance between the MACīs ahead of the NP of both surfaces…..

Offline Wolfgang Nieuwkamp

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Re: Mid engine canard
« Reply #21 on: September 07, 2016, 12:24:45 PM »
igor,

maybe the attached Castle log convinces you that my feedback system works. I agree with Tim that the integrating algorithm could be faster, but until now it works for me.

Online Brett Buck

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Re: Mid engine canard
« Reply #22 on: September 07, 2016, 12:47:56 PM »
I can't remember the name of the method*, but it's based on the fact that when you subtract a number you generate a string of ones:

   That's also how many floating-point units work, even the oddball IEEE 754 types. MIL-STD-1750 floating point was designed to be able to implement it directly as the fastest method (although not th emost precise). Effectively all A/D convertors use something nearly identical implemented in analog and TTL logic. In fact, the design of A/D almost certainly greatly predated Booth working out the general principle.

    Brett

Offline jim gilmore

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Re: Mid engine canard
« Reply #23 on: September 07, 2016, 04:07:35 PM »
I am Not an aircraft engineer but here is what I thought I kew about canards,s an aircraft.
The canard being the aircraft itself Not the elevator connected to the front of the aircraft, weather it have an elevator and horizontal stabalizer or just a fully rotating elevereon <sp>.
That the wing itself will not stall because the smaller elevator is meant to stall first .
So yes, The elevator may  well stall on a canard.
That is my understanding of the inherent stability of a canard aircraft.
Bear in mind that diheadral works in a similar way to make an aircraft stable.

Offline Tim Wescott

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Re: Mid engine canard
« Reply #24 on: September 07, 2016, 05:06:26 PM »
   That's also how many floating-point units work, even the oddball IEEE 754 types. MIL-STD-1750 floating point was designed to be able to implement it directly as the fastest method (although not th emost precise). Effectively all A/D convertors use something nearly identical implemented in analog and TTL logic. In fact, the design of A/D almost certainly greatly predated Booth working out the general principle.

For the most part, in order to retain my sanity, I view digital logic as a black box with lines coming in from the outside and magic inside.

Unless I need to convince some digital guy that I have an approach that is, too, possible -- then I suddenly find enough competence to convince his manager that I could do it given time.  That usually sparks a territorial response that results in him doing all the skut work to make it happen.
AMA 64232

The problem with electric is that once you get the smoke generator and sound system installed, the plane is too heavy.

Online Brett Buck

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Re: Mid engine canard
« Reply #25 on: September 07, 2016, 08:36:36 PM »
For the most part, in order to retain my sanity, I view digital logic as a black box with lines coming in from the outside and magic inside.

Unless I need to convince some digital guy that I have an approach that is, too, possible -- then I suddenly find enough competence to convince his manager that I could do it given time.  That usually sparks a territorial response that results in him doing all the skut work to make it happen.

  I needed to know how the guts worked for several of my past assignments, including programming processors down to the machine code level, not assembly, literally directly setting the ones and zeros, and generating self-modifying code (which generally unwise but invaluable when you have very tight space constraints). I had the advantage/opportunity to be around for the end of TTL logic as the primary method of operating to very simple flight computers, and also endless free time and lots of paid time to kill with literally nothing else to do.

    You would be surprised at how many "quirks" and errors some processors have in the microcode and similar levels. I know of one processor (Teledyne 1750A) that has about two fullpages of one-line descriptions of instructions that don't work exactly as expected in some conditions. Many of them were discovered by either me or some of my compatriots.

      Brett

Online Brett Buck

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Re: Mid engine canard
« Reply #26 on: September 07, 2016, 10:21:48 PM »
The CG seems best if ahead of the main wing. 

     But his point was that you need the leadouts to be about 3/4" to 1" behind the CG, which means they need to be in front of the wing. You certainly cannot put the CG near the CP of the wing, that's why canards don't fly all that well. Hunt's wing had lots of forward sweep so the leadouts could be in the wingtip.

      Brett

Online Brett Buck

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Re: Mid engine canard
« Reply #27 on: September 07, 2016, 10:33:59 PM »
No, it is really not what I do :-) ... mine timer is feed forward, not feed back, so it is not PIDsomething at all :- )) ... simply it adds nose up and that is all :- ))

   Do you only use one axis of the accelerometer (X/fore and aft)?  I had assumed that you used the X (fore/aft acceleration) and Z (load factor) axes as feedforwards, and the Y just like you used the swing-weight on the mechanical system to control the gross lateral acceleration/speed. The latter would indeed need a very slow filter.

       Brett

Offline Igor Burger

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Re: Mid engine canard
« Reply #28 on: September 10, 2016, 03:26:45 PM »
The problem for the rest of us is that you're a programmer and a better pilot than almost any of us can hope to be.

And that means lot of flying and less time for testing and programing :- )))))))))))))

Offline Igor Burger

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Re: Mid engine canard
« Reply #29 on: September 10, 2016, 03:46:53 PM »
igor,

maybe the attached Castle log convinces you that my feedback system works. I agree with Tim that the integrating algorithm could be faster, but until now it works for me.

Well ... I believe it does "something" as I wrote. I also tried to see such chards but it did not show correlation to maneuver, so I decided to install full set of sensors, including pitot tube, altimeter etc ... and it still did not tell me more then real tests. I was able to see lagg, I saw speed lose, but it did not tell too much. The point is ability to say what it really have to do, it is much less obviouse then one can think :- ))) ... constant speed is not the answer (btw constant to what?) as well as constant line tension etc. It needs simply tuning, testing, tuning, testing, tuning, testing :- )))

Offline Tim Wescott

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Re: Mid engine canard
« Reply #30 on: September 10, 2016, 03:58:02 PM »
(btw constant to what?)

If you have perfect inertial sensors you could make the speed constant in inertial space.
AMA 64232

The problem with electric is that once you get the smoke generator and sound system installed, the plane is too heavy.

Offline Igor Burger

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Re: Mid engine canard
« Reply #31 on: September 10, 2016, 03:59:36 PM »
   Do you only use one axis of the accelerometer (X/fore and aft)?  I had assumed that you used the X (fore/aft acceleration) and Z (load factor) axes as feedforwards, and the Y just like you used the swing-weight on the mechanical system to control the gross lateral acceleration/speed. The latter would indeed need a very slow filter.

       Brett

I use only X (lines) and Y (thrust), means no Z (the lift). From X and Y is calculated fuselage angle to horizont (in 3d). I was surprised, but in math, Z was eleminated :- )) .

Offline Igor Burger

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Re: Mid engine canard
« Reply #32 on: September 10, 2016, 04:08:50 PM »
If you have perfect inertial sensors you could make the speed constant in inertial space.

Well we spoke about it on compuserve many years ago, so some guys will remember ... you must count with wind, it makes problems and differences ... then ... flying high speed overhead when you have limited power for braking just before diving is also not the best situation for good pull-out in wingover (and not only) :- ))

But you are right, it will work well in gym indoors :- )) That is why I have different system for indoors and different outdoor.

Online Brett Buck

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Re: Mid engine canard
« Reply #33 on: September 10, 2016, 09:31:12 PM »
I use only X (lines) and Y (thrust), means no Z (the lift). From X and Y is calculated fuselage angle to horizont (in 3d). I was surprised, but in math, Z was eleminated :- )) .

      I would think you could get even more lead on acceleration by using the Z axis to detect the load factor/lift/drag.

     Brett

Offline Igor Burger

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Re: Mid engine canard
« Reply #34 on: September 11, 2016, 03:02:29 AM »
Probably yes, but I was happy I can keep all in small PIC processor in 16bit math, so I was happy I not need Z :- ))

Offline Peter Germann

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Re: Mid engine canard
« Reply #35 on: September 11, 2016, 04:16:44 AM »
Dear Friends,

While I do respectfully adore, rather than really understand, how far you have gone in automatic power control nowadys, I begin to wonder where this will lead to. Will we, in order to remain competitive, frequently need to have (buy) latest generation power management systems consisting of black boxes being connected to various sensors? If so, how does such a perspective fit into the "keep it simple" paradigm of our sport?
 
Perhaps, instead of pushing automatic power control to the n'th degree, we may want to go one step back by giving the pilot in command throttle authority? After all, power management by the driver is part of the game in aerobatics of all kind and I do not really see a reason why this should not be so in c/l stunt. Possibly not only with electrics, but when using very quick responding modern r/c motors, too, further levelling the playfield.


 
Peter Germann

Offline Igor Burger

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Re: Mid engine canard
« Reply #36 on: September 11, 2016, 04:41:12 AM »
Well, Peter the timer which I use was done on very begin of electric power train. It simply imitates almost exactly what 4-2-4 or piped setup does (I can even show you relation in setup values in timer to physical parameters of piped setup). Since then I did not change it beside small changes allowing to use it with IC engines and carburator (and I told myself not to do it just for the reason you mentioned). So I do not know where your feeling comes from. I would say just opposite, that manual controll will push us to use new devices because it simply gives too much advantage in some maneuvers. That was reason why I always disagreed with remote controll of power train and the only thing which was acceptable for me was EMERGENCY cut off - not the cut off for proper landing approach relative to wind etc - something hard to do with IC. I personally do not see reason for redefining C/L stunt. But may be I am too conservative :- )))

BTW I cannot imagine how to disallow that thing with IC engines as it is its natural property developed during years :- ))

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Re: Mid engine canard
« Reply #37 on: September 11, 2016, 09:15:43 AM »
Dear Peter,
I think you lead the things in a wrong way.
Control line flying will never lose the old stunt masters which like to use piston engines. I guess you heard about Mr. Dave Fitzerald and since i know him in the top 5 fliers in the world he still use it and more over enjoy it. The problem if we consider as problem has never been electric motors and their power equipment. If we so regulary  base the problems like that i would than say - easy for transportation, especially over the other side of the globe for a contest, more clean, more silent and so on. Never the less at the end lets dont forget that all guys started up with piston engines in the begining. Mr. Bob Hunt changes the things in other direction as design and concept of cl models, and Mr. Igor Burger completed that changed becoming first world and european champion with electric system. Many articles were dedicated to both of them in stunt hanger, many explanation notes and great articles from Mr. Paul Walker....
The fact that something grown up and changed the old style (a little bit ) it doesnt make ot bad and it doesnt make the old un necessary. This is called evolution and exist in every sport, so far conected in industry and production.
The things on which we can stress in F2B are far away from that. Personally i like to see new motivated people, inventors, experimentors. Thats speaks only about that people in CL are not fallen asleep and goes together with the world of communication and technology.
Sincerely Tatyana

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Re: Mid engine canard
« Reply #38 on: September 11, 2016, 11:05:32 AM »
Dear Peter,
I think you lead the things in a wrong way.
Control line flying will never lose the old stunt masters which like to use piston engines. I guess you heard about Mr. Dave Fitzerald and since i know him in the top 5 fliers in the world he still use it and more over enjoy it. The problem if we consider as problem has never been electric motors and their power equipment. If we so regulary  base the problems like that i would than say - easy for transportation, especially over the other side of the globe for a contest, more clean, more silent and so on. Never the less at the end lets dont forget that all guys started up with piston engines in the begining. Mr. Bob Hunt changes the things in other direction as design and concept of cl models, and Mr. Igor Burger completed that changed becoming first world and european champion with electric system. Many articles were dedicated to both of them in stunt hanger, many explanation notes and great articles from Mr. Paul Walker....
The fact that something grown up and changed the old style (a little bit ) it doesnt make ot bad and it doesnt make the old un necessary. This is called evolution and exist in every sport, so far conected in industry and production.
The things on which we can stress in F2B are far away from that. Personally i like to see new motivated people, inventors, experimentors. Thats speaks only about that people in CL are not fallen asleep and goes together with the world of communication and technology.
Sincerely Tatyana

100% YES!!!  :)

Offline Matt Spencer

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Re: Mid engine canard
« Reply #39 on: September 19, 2016, 08:35:17 PM »
 ;D


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Re: Mid engine canard
« Reply #40 on: September 21, 2016, 03:44:23 PM »
But Canards CANT stall .  ;D
Well, I do get your meaning beyond the wording Matt.

When the fore plane does stall it does so long before the main plane should do (loading and CG not withstanding).
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Re: Mid engine canard
« Reply #41 on: March 05, 2017, 10:04:31 AM »
Well, I do get your meaning beyond the wording Matt.

When the fore plane does stall it does so long before the main plane should do (loading and CG not withstanding).
.

I would say it depends on the aspect ratio of the canard WRT that of the wing. 

Canards are, for a preponderance of aerodynamic and mechanical reasons, inherently flawed aircraft, which explains why in the never ending search for speed and performance they have been pretty well kicked to the wayside.
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Offline Avaiojet

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Re: Mid engine canard
« Reply #42 on: March 05, 2017, 10:31:37 AM »
I would say it depends on the aspect ratio of the canard WRT that of the wing.  

Canards are, for a preponderance of aerodynamic and mechanical reasons, inherently flawed aircraft, which explains why in the never ending search for speed and performance they have been pretty well kicked to the wayside.

Are you sure?



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Offline Avaiojet

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Re: Mid engine canard
« Reply #43 on: March 05, 2017, 10:35:33 AM »
Are you really really sure?

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Re: Mid engine canard
« Reply #44 on: March 05, 2017, 12:34:18 PM »
Are you really really sure?



Yes, I'm very sure. 

Canards have some major drawbacks. First, why would you place your wing in wash of the stab? 

Second, and most importantly, aircraft store fuel and weapons in and under the wings. When you try to drop a bomb or fire a missile, or just burn fuel, the CG on a canard moves around too much.




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Offline Avaiojet

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Re: Mid engine canard
« Reply #45 on: March 05, 2017, 12:54:23 PM »
Yes, I'm very sure. 

Canards have some major drawbacks. First, why would you place your wing in wash of the stab? 

You could say the same for a wing that's forward of the stab. Probably more so.

 

Quote
Second, and most importantly, aircraft store fuel and weapons in and under the wings. When you try to drop a bomb or fire a missile, or just burn fuel, the CG on a canard moves around too much.


On aircraft, the CG is a plus or minus measurement covering a designated area designed into the aircraft to allow for what you mentioned.

Controlled by "trim" input, as, what you're talking about, changes.

Simple decrease in RPM's will require a trim change.

I think the aircraft in the photos deserve some technical and design kudos.

Designed by people who certainly know a great deal about aircraft design.

The aircraft that circled the globe, I don't remember the name it was called, evidently the Conard design was realized for efficiency and usefulness for the purpose it was designed for.

They didn't go traditional and they easily could have.

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Offline Mark Scarborough

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Re: Mid engine canard
« Reply #46 on: March 05, 2017, 01:52:55 PM »
You could say the same for a wing that's forward of the stab. Probably more so.

 
 

On aircraft, the CG is a plus or minus measurement covering a designated area designed into the aircraft to allow for what you mentioned.

Controlled by "trim" input, as, what you're talking about, changes.

Simple decrease in RPM's will require a trim change.

I think the aircraft in the photos deserve some technical and design kudos.

Designed by people who certainly know a great deal about aircraft design.

The aircraft that circled the globe, I don't remember the name it was called, evidently the Conard design was realized for efficiency and usefulness for the purpose it was designed for.

They didn't go traditional and they easily could have.

CB 

Charles, no you are wrong,
on a Canard, the CG is way ahead of the wing, hence if you have wing mounted stors, missles etc, or wing fuel tanks it will dramatically alter the CG, with a conventional setup, the CG is in the wing area, therefore releasing stores, burning fuel will have a significantly reduced affect on the CG.
please also note, we are in a STUNT sectionj of the forum, NOT in a sport section, therefore all answers are by default aimed at stunt airplanes and ther design, if a Canard was such agreat idea, I am pretty sure someone would have done it and we would have seen it at the Nats or at least a major contest.

The Voyager was a canard for different reasons that anything described here, it wa also designed by Rutan who had a thing for canards, the others had inherant problems in the design as well. Yes they were cool, and unique but if they were that great, pretty sure more would have followed in their footsteps,,
so Charles, sorry but you are wrong
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Re: Mid engine canard
« Reply #47 on: March 22, 2017, 08:07:07 PM »
Wolfgang,  I'd go back and check you earlier canard, and the plans for the Blue Goose.  I flew one of those a friend built.  With the flaps fixed and just the canard it flew pretty well, about like a Ringmaster.  Had similar behavior too.  It was easy to stall the canard if trying square corners, but it glided just fine.  I suspect you have a CG problem or the perhaps the swept forward wing puts the CG too far forward, putting too much load on canard when gliding.

The Canela is a pretty plane.  I hope you can get the problem fixed.

If I remember correctly, the Blue Goose had the CG just forward of the wing.  Unfortunately my friend died quite a few years ago and the plane got lost in the shuffle, so I can't check.

Phil C.
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Re: Mid engine canard
« Reply #48 on: March 22, 2017, 09:31:21 PM »
On aircraft, the CG is a plus or minus measurement covering a designated area designed into the aircraft to allow for what you mentioned.

   No. The CG is where the airplane balances, period, and it is a point, not a range. Sometimes an allowable range of CG positions is specified, and it moves around in flight, but at any instant in time, it is a single point.

    Brett

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Re: Mid engine canard
« Reply #49 on: March 22, 2017, 11:11:19 PM »

............ on a Canard, the CG is way ahead of the wing ............

Not always, on full size and non control line aircraft the center of gravity must be ahead that of the Neutral point by factor called static margin which should be between 5 to 15 % of the mean aerodynamic chord.
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