Reducing the rotation speed

[vonjet]

How do we reduce the rotation speed on these canards? Any mods you can do to improve this area?

[Waiter]

Operate at the aft CG limit. Will reduce the rotation speed (the Canard is lifting less weight) but may increase the Takeoff speed ever so slightly (The aft wing is now lifting more weight)

 

Waiter

[argoldman]

Vortex generators have a good effect on many aircraft. With the Canards, it is important to have them on both the wing and the canard.

 

Mark Beduhn has them on his.

[JLKnolla]

I will put in my $.03 ($.02 adjusted for inflation). The question really relates to my biggest putoff with canards, takeoff (TO) performance.

 

Canard takeoff performance is limited by several things when compared to a conventional aircraft, lifting power of the canard, cg position, low overall CLMax (can't use flaps on main wing without some exotic mechanisms like the Starship's variable geometry canard to maintain the aerodynamic balance between wing and canard), lack of prop blast on pitch control and poor acceleration.

 

Only a couple of these are things you can actually do something about with a given design, mainly acceleration and CG. Operate light and at aft CG like Waiter says, or move to a CS prop to increase the rate of acceleration. Since most EZ's seem to have cruise pitched props, acceleration is just plane slow, couple that with limited lifting ability and we really can't expect anything other than the TO performance we get. Changing landing gear geometry (main wheel axle location) could improve TO performance

 

In fact, it would be interesting to get Waiter's opinion on TO performance with the prop change on his Long. Others have commented that TO performance in the few CS prop equipped Cozy's is significantly better than for fixed pitch props - I suspect Waiter can really feel it but am interested in his observations rather than my own suspicions.

[Vortal]

Just shorten the main gear, or make the nose gear longer to increase your angle of incidence, you'l have more lift at the same speed (increase of angle of attack) the stagger-EZ is like that

no need to play with aero or CG

the only thing that will happen is you'll reduce your magin to the stall speed that's it

be carefull of any prop strike...

(my $ 0.022 CAD...

[Lynn Erickson]

Just shorten the main gear, or make the nose gear longer to increase your angle of incidence, you'l have more lift at the same speed (increase of angle of attack) the stagger-EZ is like that

no need to play with aero or CG

the only thing that will happen is you'll reduce your magin to the stall speed that's it

be carefull of any prop strike...

(my $ 0.022 CAD...

changing the gear length will not change the angle of incidence only the angle of attack while on the ground. this will have no effect on stall. to change the incidence of the wing or canard you would have to change the angle relative to the fuselage

[Lynn Erickson]

I will put in my $.03 ($.02 adjusted for inflation). The question really relates to my biggest putoff with canards, takeoff (TO) performance.

 

Canard takeoff performance is limited by several things when compared to a conventional aircraft, lifting power of the canard, cg position, low overall CLMax (can't use flaps on main wing without some exotic mechanisms like the Starship's variable geometry canard to maintain the aerodynamic balance between wing and canard), lack of prop blast on pitch control and poor acceleration.

 

Only a couple of these are things you can actually do something about with a given design, mainly acceleration and CG. Operate light and at aft CG like Waiter says, or move to a CS prop to increase the rate of acceleration. Since most EZ's seem to have cruise pitched props, acceleration is just plane slow, couple that with limited lifting ability and we really can't expect anything other than the TO performance we get. Changing landing gear geometry (main wheel axle location) could improve TO performance

 

In fact, it would be interesting to get Waiter's opinion on TO performance with the prop change on his Long. Others have commented that TO performance in the few CS prop equipped Cozy's is significantly better than for fixed pitch props - I suspect Waiter can really feel it but am interested in his observations rather than my own suspicions.

yes you can feel it, the take off is improved with the CS prop by about 25% but top end suffers. the CS props are not set up with the same twist and airfoil so they are not optimized for top end and on an EZ they loose about 10 KTS. I have flown a couple of EZ both with new and old styles of MT blades and on the same plane with fixed pitch and they both fell short on top speed with the CS prop.

[Vortal]

changing the gear length will not change the angle of incidence only the angle of attack while on the ground. this will have no effect on stall. to change the incidence of the wing or canard you would have to change the angle relative to the fuselage

you don't decrease you stall speed, you decrease your margin to stall speed, instead of rotating at 1.2x stall speed, you rotate at 1.1 (fake values, for example) once you rotated, it's the same deal as before, same stall speed, same everything, and by doing that you do increase your angle of attack on the ground compared to a standard landing gear arrangement

 

i was confusing attack and incidence... in french, angle of attaque and angle of incidence is the same thing, the angle of incidence in english is the wedging of the wing (calage) in french...

 

From the stagger EZ website :

"The aircraft will “sit” at a +1.5 degree angle on the ground which should allow for a “shorter” takeoff roll as the EZ is being pushed down the runway by 190 HP"

http://www.wrightaircraft.com/Stagger_EZ/body_stagger_ez.htm

[longez360]

EZ's sit at a variety of attitudes with people on board. I simply moved the microswitch to give max extension on the nose gear with people on board. This made some difference.

 

Bottom line: For me it was about takeoff acceleration (and the ability to decelerate an increased MTOW LEZ from the decision point (good brake steup)). I chose an O-360, a Hertzler climb prop (2500+RPM static), W50LT brakes (with good insulation) and have removed a lot of excess weight. That's a massive safety increase for mine.

 

Again, better to get to Vr quick.

[Lynn Erickson]

 

From the stagger EZ website :

"The aircraft will “sit” at a +1.5 degree angle on the ground which should allow for a “shorter” takeoff roll as the EZ is being pushed down the runway by 190 HP"

http://www.wrightaircraft.com/Stagger_EZ/body_stagger_ez.htm

I did all that and it made no difference in take off length. it took longer to accelerate to take off speed, more drag during the roll. the best way for me is to keep it all low drag and until you get the speed and then rotate. if you try to pull it off early you might get it off the ground a few feet shorter but you might not make the fence. it will just hang there in ground effect until you put the nose down to gain some speed so you can climb.

[jhicks]

EZ's sit at a variety of attitudes with people on board. I simply moved the microswitch to give max extension on the nose gear with people on board. This made some difference.

 

Bottom line: For me it was about takeoff acceleration (and the ability to decelerate an increased MTOW LEZ from the decision point (good brake steup)). I chose an O-360, a Hertzler climb prop (2500+RPM static), W50LT brakes (with good insulation) and have removed a lot of excess weight. That's a massive safety increase for mine.

 

Again, better to get to Vr quick.

 

 

Whats your cruise speed with the climb prop? How hard was it to get the CG right with an 0-360?

 

Jamie

[steve]

you don't decrease you stall speed, you decrease your margin to stall speed, instead of rotating at 1.2x stall speed, you rotate at 1.1 (fake values, for example) once you rotated, it's the same deal as before, same stall speed, same everything, and by doing that you do increase your angle of attack on the ground compared to a standard landing gear arrangement

 

i was confusing attack and incidence... in french, angle of attaque and angle of incidence is the same thing, the angle of incidence in english is the wedging of the wing (calage) in french...

 

From the stagger EZ website :

"The aircraft will “sit” at a +1.5 degree angle on the ground which should allow for a “shorter” takeoff roll as the EZ is being pushed down the runway by 190 HP"

http://www.wrightaircraft.com/Stagger_EZ/body_stagger_ez.htm

we sat at RR and looked at TO roll's and we could see the planes that would lift off early because of the aoa to the ground the higher the canardthe faster they fly(nutting was helped by this posting)