REFLECTOR: AOA indicator

Tue Nov 8 06:34:30 CST 2011

Brian,

What you say makes sense, but all we care about is when the canard will stall. In a gradual stall the critical angle of attack for the canard will be a factor of both the angle of the fixed part of the canard (linked directly to the fuselage) and the angle of the variable part, the elevator, as you described. But where will the elevator be?  Somewhere close to all the way down. Since we know where the variable part will be in relation to the fixed part we can use the fixed AOA. 

I suppose it's possible to stall the canard with something less than full elevator, I'll have to test fly and see. But I do know that in my plane to get a hard stall break on the canard you have to pull the stick all the way back. That's the scenario I want to avoid on landing. 

So as a practical matter, the AOA of the fuselage does give us a good indication of the critical AOA of the canard with the elevator deflected down. The indicator shows red, yellow and green bands, not the actual angle. It's calibrated in flight so the red indicates the angle at which a stall will occur. In our case that means the angle the canard will stall with full down elevator. 

I know from using it that single pilot I can fly my approach at 80 knots and the AOA will be near the green and yellow border. If I put someone in the copilot seat the same AOA will occur at a higher airspeed, just as you would expect. I can land regardless of loading with the AOA near the yellow/red border without incident.  As I said, very helpful. 

Regards,

Glenn
N697RG
Elite RG, flying

On Nov 7, 2011, at 10:25 PM, Brian Michalk <michalk at awpi.com> wrote:

> I thought an AOA on a canard would have to take into account the elevator position?
> 
> Since the trailing edge of the elevator on the canard establishes the chord, the AOA would have to be determined for that chord on the canard.  The AOA for the fuselage is the same as for the canard if you disregard the variable chord provided by the elevators.  If you are flying fast, you may get 1 degree for your angle of attack fuselage.  Slow down, and pull back on the stick, you could also get the same 1 degree AOA for the fuselage, but the canard would be flying at a higher AOA.
> 
> Or do I have this all wrong?
> 
> On 11/07/2011 11:03 AM, Glenn Babcock wrote:
>> 
>> This installation looks like it works well for a FG, but on a retract it doesn't work.  That's why I went with the right angle mount on the side of the fuselage under the canard.  I'll try to find some pictures.
>> 
>> I think that the AOA is very useful on a canard.  We don't have a stall warning system, so this gives us one.  The display shows you a range of green, yellow and red.  When you hit the red expect the canard to stall and the nose to drop.  There is a noticeable difference in the airspeed at which this occurs, depending on if you have a passenger up front or not.  I find it helps to keep the landing speeds down while knowing that you are not about to drop it in.  
>> 
>> Regards,
>> Glenn
>> 
>> N697RG
>> Elite RG, flying
>> 
>> On Nov 7, 2011, at 8:23 AM, Ruben Creus wrote:
>> 
>>> By the way, there is the picture of where it is installed. Just under the nose.
>>>  
>>> I think I like symmetry, so I did not like it hanging out on one side. In the center looks nice and reads great so far!
>>>  
>>> P.D.: This model comes with angle of attack reader, but you can read it only if you have a dynon unit. Not that you really used too much with a canard, bit nice thing to show off ;-)   
>>> <image002.jpg>
>>>  
>>> From: Chris Barber [mailto:cbarber at texasattorney.net] 
>>> Sent: Saturday, November 05, 2011 5:42 PM
>>> To: Velocity Aircraft Owners and Builders list
>>> Cc: Velocity Aircraft Owners and Builders list
>>> Subject: Re: REFLECTOR: heated pitot
>>>  
>>> Not sure of the compatibility or if it is an issue, but Dynon has a heated pitot for $450 IIRC. Much cheaper than most I think. 
>>>  
>>> Chris
>>> 
>>> Sent from my iPhone 4
>>> 
>>> On Nov 5, 2011, at 3:44 PM, "Laurence Coen" <lwcoen at hotmail.com> wrote:
>>> 
>>>> Lou,
>>>>  
>>>> I have a surplus shark fin pitot static on the nose of my plane.  The static port doesn't work because the pressure wave from the nose messes up the static reading but the pitot works fine and it's heated.  I think you would need about a 3 foot boom to get the static port to work but I expect you already have a separate static port.  If you look in the AS catalog you wont be happy at the prices.  Try this link.
>>>> http://www.barnstormers.com/classified_597429_Shark+fin+Pitot+head.html
>>>>  
>>>> Larry Coen
>>>> N136LC
>>>>  
>>>> From: Lou Stedman
>>>> Sent: Saturday, November 05, 2011 2:49 PM
>>>> To: Velocity Reflector
>>>> Subject: REFLECTOR: heated pitot
>>>>  
>>>> My standard Velo is an older model and is equipped with a VOR, ILS, and a GPS for IFR. Unfortunately it does not have a heated pitot, which I understand is required to have it IFR certified. I am planning on installing a heated pitot this winter and was wondering what others have used. Any tips or suggestions would be appreciated. Thanks
>>>>  
>>>> Lou Stedman
>>>> Velocity SEFG
>>>> N7044Q
>>>> Olean, NY
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>> 
>> 
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> 
> _______________________________________________
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> 
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