Reflexor and autopilot
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ryan goodman
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To much friction.
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ryan goodman
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What's the approximate linear throw of that mod?
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Mike Dwyer
There are many systems for Reflexor. My control for it takes more pressure than I'd expect a servo to handle. I also don't see it as a good elevator control. For instance, in flight I like to reflex the ailerons full up. This makes you have to go forward on the elevator. Now you've reduced the lift on both wings. I go 4 mph faster due to this. Yes, I have to use the elevator trim to remove the need for forward pressure on the stick but that's a very small price to pay for extra speed. On Sun, Nov 1, 2020 at 12:53 PM Cody <cody.craig1985@...> wrote: What's the approximate linear throw of that mod? |
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I found a small throw linear actuator that drives .75" with 30 ft/lbs of force. Does not move or freespin if power is lost. I think it weights 12oz? On Sun, Nov 1, 2020, 14:48 Mike Dwyer <q200pilot@...> wrote:
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ryan goodman
I'm sure that would handle the physical aspect of manipulating the control. But the issue... And what sparked my interest in the idea, is that reflexor is pretty freaking limited in it's use in aviation. At least as far as I know. So I can imagine there are many of any autopilots that know what to do with it.... If there are, I'd love to integrate it.
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ryan goodman
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Anthony P
For instance, in flight I like to reflex the ailerons full up. This makes you have to go forward on the elevator. Now you've reduced the lift on both wings. I go 4 mph faster due to this.This is very interesting. Does this suggest a change to the angle of incidence for one or both wings? Does it suggest a thinner airfoil? Maybe a C.G. shift? Is there precedence for flying faster (when straight and level) with the control surfaces out of alignment with the airfoil or not in their neutral position? |
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I see the same phenomenon as Mike reports. This is the result of minimizing the overall induced drag for both wings while still providing the necessary lift for level flight.
At high cruise at low AOA, the main wing essentially is flying at very minimal lift, but still inducing a significant forward pitching moment, thereby moving most of the overall lifting load to the canard. The canard is flying fast enough to provide essentially all the lift for the entire airplane. This reduction in loaded lifting area is not unlike commercial jets that effectively halve their lifting surface from the landing configuration to the cruise configuration.
The taildragger Q is extremely slick, so the increase in speed and RPM produced by forcing it to a lower AOA is sufficient to maintain level flight at this higher speed. The tri-gear version has to fight more parasitic drag, so more horsepower is required to keep it level, but the same characteristics are observed if you can add a little more throttle. I have a tri-gear and have tested and documented this. Of course, with similar horsepower, the taildragger will always outpace the tri-gear. The conventional Q2XX drivers will never miss the opportunity to tell you this 😊
To do what Mike suggests depends on your decalage (relative angle of the main wing with respect to the canard). With different decalage angles you may require up reflexor (Mike’s case), neutral reflexor, or even down reflexor (my case) in order to reach this optimum cruise angle. You will have to experiment. As Mike mentioned, the forward stick pressure can be significant. This is mostly because you are fighting the sparrow strainer’s down force.
Cheers, Jay Scheevel, Tri-Q2 N8WQ, 120 hours
From: main@Q-List.groups.io <main@Q-List.groups.io> On Behalf Of Anthony P
This is very interesting. Does this suggest a change to the angle of incidence for one or both wings? Does it suggest a thinner airfoil? Maybe a C.G. shift? |
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When I first started my flight testing way back in 1986, I could tell that something was wrong with my angle of incidence between the front and rear wings. So what I did, was to raise the front of the Canard a half an inch. It took me 1 week from the first cut to the paint job. I think a lot of aircraft have this problem. When I fly fast, my ailerons are faired into the wing. Sam On Mon, Nov 2, 2020, 7:10 AM Anthony P <solarant@...> wrote: For instance, in flight I like to reflex the ailerons full up. This makes you have to go forward on the elevator. Now you've reduced the lift on both wings. I go 4 mph faster due to this.This is very interesting. Does this suggest a change to the angle of incidence for one or both wings? Does it suggest a thinner airfoil? Maybe a C.G. shift? |
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One of the QAC newsletters indicated that the factory recommended increasing the angle of the canard 1 degree for all new construction. This was recommended for the GU canard, but was issued about the time that they released the LS1 canard. The same recommendation was never made in the plans for the LS1 canard (nor the GU) and was never put into the QAC newsletter for the LS1 either, but my measurements of the factory N81QA prototype with the LS1 (from photos), show that it was set up with 1 degree of increased angle on the canard compared to the plans, so I think they carried that practice over to the Q200. Essentially, N81QA was set up very similar to your airplane, Sam.
Cheers, Jay
From: main@Q-List.groups.io <main@Q-List.groups.io> On Behalf Of Sam Hoskins
When I first started my flight testing way back in 1986, I could tell that something was wrong with my angle of incidence between the front and rear wings. So what I did, was to raise the front of the Canard a half an inch. It took me 1 week from the first cut to the paint job. I think a lot of aircraft have this problem.
When I fly fast, my ailerons are faired into the wing.
Sam
On Mon, Nov 2, 2020, 7:10 AM Anthony P <solarant@...> wrote:
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My elevators fair in high speed as well. I did add 1 degree in the LS1 canard when installed.
The Reflexor does not have to be used, it just refines the controls. It does however add a couple knots if reflexed up with elevator rolled down a little.
Jim
N46JP Q200
Sent from Outer Space
From: main@Q-List.groups.io <main@Q-List.groups.io> on behalf of Jay Scheevel <jay@...>
Sent: Monday, November 2, 2020 8:24:46 AM To: main@Q-List.groups.io <main@Q-List.groups.io> Subject: Re: [Q-List] Reflexor and autopilot One of the QAC newsletters indicated that the factory recommended increasing the angle of the canard 1 degree for all new construction. This was recommended for the GU canard, but was issued about the time that they released the LS1 canard. The same recommendation was never made in the plans for the LS1 canard (nor the GU) and was never put into the QAC newsletter for the LS1 either, but my measurements of the factory N81QA prototype with the LS1 (from photos), show that it was set up with 1 degree of increased angle on the canard compared to the plans, so I think they carried that practice over to the Q200. Essentially, N81QA was set up very similar to your airplane, Sam.
Cheers, Jay
From: main@Q-List.groups.io <main@Q-List.groups.io>
On Behalf Of Sam Hoskins
When I first started my flight testing way back in 1986, I could tell that something was wrong with my angle of incidence between the front and rear wings. So what I did, was to raise the front of the Canard a half an inch. It took me 1 week from the first cut to the paint job. I think a lot of aircraft have this problem.
When I fly fast, my ailerons are faired into the wing.
Sam
On Mon, Nov 2, 2020, 7:10 AM Anthony P <solarant@...> wrote:
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So with these reports, I'm not sure if I would connect the the reflexor to the autopilot system. But an electric trim still sounds like a viable idea, with a joystick utilizing some buttons for trim next to the PTT switch. I'm not sure if an autopilot would factor the reflexor as elevator trim correctly since its on the other airfoil as the elevator servo. Most autopilot systems seek neutral force in the servo feedback. Or at least stec, century, Collins do. I'm not sure about Garmin, dynon, or skytrak.
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Anthony P
I'm getting a little confused here. I swear I'm reading conflicting info.
When you reflex up, the trailing edge of the ailerons point up, correct? This produces a nose up tendency and is used on approach to reduce the amount of aft stick needed to maintain glide path and to allow more aft stick for slower airspeed when in ground effect? When you push forward on the stick, the trailing edge of the elevators point up, correct? This produces a nose down tendency? Isn't there an optimum fuselage angle and optimum canard and wing angles that create the least drag for a give C.G. when all the control surfaces are inline with their respective chord? |
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ryan goodman
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If you really want to dig into this. I have done a three part modeling study on the subject and all of the terms are defined and analyzed. I did not delve heavily into the topic of using reflexor to optimize cruise, since I was mostly concerned with landing configurations, but so far my modeling is consistent with my flight observations as well as Sam and Mike’s. So… I expect that I could do some modeling of using reflexor during cruise, however I am more inclined to spend my spare time flying these days. Here are the links for the study:
http://n8wq.scheevel.com/documents/All_Text_and_figures_Part1.pdf http://n8wq.scheevel.com/documents/All_Text_and_figures_Part2.pdf http://n8wq.scheevel.com/documents/All_Text_and_figures_Part3.pdf
Cheers, Jay
From: main@Q-List.groups.io <main@Q-List.groups.io> On Behalf Of Anthony P
I'm getting a little confused here. I swear I'm reading conflicting info. |
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Well, that's certainly something to chew on.
I have actually skimmed this before, but obviously didn't get enough out of it to understand that flying with what seem like "dirty" wings can actually produce a "clean" system. Thank you for the study and for posting them here. |
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