Full power takeoff!

Vance

Gyroplane CFI
Staff member
Joined
Oct 30, 2003
Messages
18,363
Location
Santa Maria, California
Aircraft
Givens Predator
Total Flight Time
2600+ in rotorcraft
In all the gyroplanes I have flown the throttle allows me to adjust the power so that I don’t give her too much power too soon during the takeoff roll.

I feel having any flight control at the limit reduces my options if something changes.

I recently read in a post that full right rudder is required to takeoff in a 915 powered Cavalon because it has a design flaw and if full power is not applied immediately the climb out will be too slow to clear a 50 foot obstacle.

This poster apparently feels flying with the rudder against the stop is safe and the design flaw forces him to use full rudder deflection on takeoff.

I do not agree.

I called two of my aviation mentors to make certain I was not giving bad advice.

I feel based on my experience the Cavalon is a well designed aircraft and when flown well has sufficient control authority to manage all phases of flight without reaching the limit of any of the flight controls.

I like having the Cavalon pointed down the runway during the takeoff and would not want the rudder at the stop in case the wind changed.

I found that by modulating the power I can climb out quickly in a 915 powered Cavalon without reaching full deflection of the rudder.

In my opinion full throttle should not be used until I have attained sufficient indicated airspeed to have full control authority without using full rudder deflection.
 

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P-factor. That requires rudder input. Reduce p-factor and it will not require so much rudder. Go to your instructor and understand why P-factor would happen. Understand it correctly and you will understand how to develop the right technique not to have to use full rudder on full power climb out. If we as pilots do not understand basic physics behind flying and controls then we are likely to do things by rote. The worst way to fly.
 
That would be me Vance complaining about, my friends.
The good the bad and the ugly.

Well, I'll see you 2 mentors and raise you 3 of my instructors I just got off the phone with.
I asked, "Aren't you at full right rudder when you fly the 915's on takeoff."
The answer after a laughed, was "yes by all 3, and by two full right rudder left stick in all of them". No hesitation by all 3 and from one said in the MTO 915's it is always that way.

Then I told only one of them, Henry, that Vance is condemning flying 915's with full right rudder on the premises if the wind changes you may need it.
I laughed and said, "for goodness sake, any pilot instantly would just reduce power and back pressure on the stick lowering the nose until I have the rudder back. Geeeeeeees".
It is about as automatic as putting the nose back to the horizon when you change the power settings in Autogyros.

However, Henry hedged his answer once he discovered it was Vance condemning me, and the 3 of them.
And said well "with your low weight you sure don't need it most of the time".
So then I specifically asked Henry "Should I just use 5500 as I did for the check ride?" as it really does bother me being at full stop.
Well if it bothers you use 5500.

In a FW hitting full stop on landing means going around in crosswinds.


Sigh... no more showing fixed wingers over 1000-a-minute climb rate for me.
When I'm flying two I'll do as you say and fly 5500 but when alone, please leave me alone.
 
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I had the pleasure of being friends with a WWII ace who flew P47 Thunderbolts, with an 18 cylinder 2000 hp radial. Bob reported that the P-factor and precession on that beast required a strong right leg and every degree of rudder travel possible on takeoff. In wartime, in that aircraft, with a full load of ordnance for a combat mission, I can understand routine use of full control deflection. In any other setting, it seems foolish to me.
 
That would be me Vance complaining about, my friends.
The good the bad and the ugly.

Well, I'll see you 2 mentors and raise you 3 of my instructors I just got off the phone with.
I asked, "Aren't you at full right rudder when you fly the 915's on takeoff."
The answer after a laughed, was "yes by all 3, and by two full right rudder left stick in all of them". No hesitation by all 3 and from one said in the MTO 915's it is always that way.

Then I told only one of them, Henry, that Vance is condemning flying 915's with full right rudder on the premises if the wind changes you may need it.
I laughed and said, "for goodness sake, any pilot instantly would just reduce power and back pressure on the stick lowering the nose until I have the rudder back. Geeeeeeees".
It is about as automatic as putting the nose back to the horizon when you change the power settings in Autogyros.

However, Henry hedged his answer once he discovered it was Vance condemning me, and the 3 of them.
And said well "with your low weight you sure don't need it most of the time".
So then I specifically asked Henry "Should I just use 5500 as I did for the check ride?" as it really does bother me being at full stop.
Well if it bothers you use 5500.

In a FW hitting full stop on landing means going around in crosswinds.


Sigh... no more showing fixed wingers over 1000-a-minute climb rate for me.
When I'm flying two I'll do as you say and fly 5500 but when alone, please leave me alone.
In my opinion it is not a choice between full power and full rudder deflection or climbing out at a lower power level.

As my airspeed increases my control surfaces become more effective by the square of the increase in my airspeed so as my airspeed increases I may increase my throttle without reaching the limits of my rudder authority.

In other words at fifty knots of indicated air speed I have four times the rudder authority I do at twenty five knots of indicated air speed.

In my opinion if I need full rudder deflection for my takeoff I am being premature with my throttle application.

In my opinion with a full throttle, full rudder deflection climb out if my engine goes quiet it will not end well.

Based on my experience when someone crashes a gyroplane because of pilot error the fixed wing pilots you are trying to impress with your steep angle of climb will blame it on the gyroplane.

I suspect this kind of inanity is why most gyroplane flight instructors don’t participate on the Rotary Wing Forum.

What you think you heard your flight instructor say may be very different than your flight instructor posting their opinion on the Rotary Wing Forum.
 
I had the pleasure of being friends with a WWII ace who flew P47 Thunderbolts, with an 18 cylinder 2000 hp radial. Bob reported that the P-factor and precession on that beast required a strong right leg and every degree of rudder travel possible on takeoff. In wartime, in that aircraft, with a full load of ordnance for a combat mission, I can understand routine use of full control deflection. In any other setting, it seems foolish to me.
I agree. If you are using all of your controls travel to maintain control they need to be altered. With this new 915 it would seem that it may need redesign on the rudder so it’s more effective. On that beast John is flying it should just be a matter of rigging to get more travel. If that is not able to be done then the flight handbook should be changed. Never flown one but from all accounts I have heard the 915 is a torque monster. Maybe these factory machines should change their rudder to account for this instead of just mounting the bigger engine on and going. I would have thought they would have test flown the first one and discovered it needs more or more affective rudder. They might be ugly but a Tall Tail is well suited for the task. I never known anyone to complain about hitting the rudder stop on Dominator. When I flew with Greg the AR1 had plenty of Rudder left with a 914. It has been redesigned and tested a bunch.
 
In all the gyroplanes I have flown the throttle allows me to adjust the power so that I don’t give her too much power too soon during the takeoff roll.

I feel having any flight control at the limit reduces my options if something changes.

I recently read in a post that full right rudder is required to takeoff in a 915 powered Cavalon because it has a design flaw and if full power is not applied immediately the climb out will be too slow to clear a 50 foot obstacle.

This poster apparently feels flying with the rudder against the stop is safe and the design flaw forces him to use full rudder deflection on takeoff.

I do not agree.

I called two of my aviation mentors to make certain I was not giving bad advice.

I feel based on my experience the Cavalon is a well designed aircraft and when flown well has sufficient control authority to manage all phases of flight without reaching the limit of any of the flight controls.

I like having the Cavalon pointed down the runway during the takeoff and would not want the rudder at the stop in case the wind changed.

I found that by modulating the power I can climb out quickly in a 915 powered Cavalon without reaching full deflection of the rudder.

In my opinion full throttle should not be used until I have attained sufficient indicated airspeed to have full control authority without using full rudder deflection.
They do not want to be attacked by you and Jim Et el. and never post on the forum the same for many CFIs, Micheal, Camy, and many more don't post here anymore. I do not mind being attacked. Call Henry and verify I'm telling you exactly what happened! And if I was like you the same could be said for your two mentors.
I climb out at 80 MPH not anywhere near 50 ever!!!!
Understanding the physics of P factor, I posted the solution to flying on the edge of the rudder curve if there is such a thing. You simply reduce power to 5300 while reducing back pressure on the stick to maintain 80MPH until you have the rudder back.
I've practiced this many many times in the AG915 so it will be automatic if ever hit by a gust of wind.

If that is not correct please correct it until correct and in the future could you at least say. If you insist on flying with a full right rudder at least learn this can happen and practice maneuver X (explain the maneuver as I did) to keep out of trouble.
Instead of only offering condemnation explain the danger (that I'm well aware of) and provide the solution to stay out of trouble should a wind gust hit you and tell them to practice it until automatic.
 
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As my airspeed increases my control surfaces become more effective by the square of the increase in my airspeed so as my airspeed increases I may increase my throttle without reaching the limits of my rudder authority.

In other words at fifty knots of indicated air speed I have four times the rudder authority I do at twenty five knots of indicated air speed.

In my opinion if I need full rudder deflection for my takeoff I am being premature with my throttle application.

In my opinion with a full throttle, full rudder deflection climb out if my engine goes quiet it will not end well.
Very well-articulated Vance.

Use only the power that is needed for the task at hand. Don't just select 5500 RPM because that's what you used on your check ride. What if 5000 is enough for today? or some other number?

Gradual power addition. As airspeed builds, the rudder becomes more effective, and more power can be selected for the same rudder deflection.

This is really basic stuff that I would have thought was understood by anyone that flies.
 
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They do not want to be attacked by you and Jim Et el. and never post on the forum the same for many CFI, Micheal, Camy, and many more. Call Henry and verify I'm telling you exactly what happened!
I climb out at 80 MPH not anywhere near 50 ever!!!!
Understanding the physics of P factor, I posted the solution to flying on the edge of the rudder curve if there is such a thing. You simply reduce power to 5300 while reducing back pressure on the stick to you maintain 80MPH until you have the rudder back.
I've practiced this many many times in the AG915 so it will be automatic if ever hit by a gust of wind.

If that is not correct please correct it until correct and in the future could you at least say. If you insist on flying with a full right rudder at least learn this can happen and practice maneuver X (explain the maneuver as I did) to keep out of trouble.
Instead of only offering condemnation explain the danger (that I'm well aware of) and provide the solution to stay out of trouble should a wind gust hit you.
My post was about the solution John.

Don't be premature with the power.

I suspect lowering the nose will help too.

P-factor, or asymmetric propeller loading, causes a left turning tendency in Rotax 9 series pusher gyroplanes when the aircraft has a high angle of attack. This is caused by the propeller angle on the right side of the aircraft experiencing a larger angle of attack (and therefore more thrust) than the left.
 
I agree. If you are using all of your controls travel to maintain control they need to be altered. With this new 915 it would seem that it may need redesign on the rudder so it’s more effective. On that beast John is flying it should just be a matter of rigging to get more travel. If that is not able to be done then the flight handbook should be changed. Never flown one but from all accounts I have heard the 915 is a torque monster. Maybe these factory machines should change their rudder to account for this instead of just mounting the bigger engine on and going. I would have thought they would have test flown the first one and discovered it needs more or more affective rudder. They might be ugly but a Tall Tail is well suited for the task. I never known anyone to complain about hitting the rudder stop on Dominator. When I flew with Greg the AR1 had plenty of Rudder left with a 914. It has been redesigned and tested a bunch.
On that beast John is flying it should just be a matter of rigging to get more travel.
Now that is a brilliant maybe easy solution Mike!!!
I'm going back to the hangar and see if I can add a lever to the rudder push-pull tube and extend the travel. If anyone knows a way to do that with push-pull tubes I appreciate learning an easy fix for all the Cavalons, Argons, and AG915s. There isn't much travel on the twin rudders!! Good one Mike. I love this forum when they offer solutions and not condemnation.
 
Thank you, Mike. It appears I can add a lever and a little longer cable to extend the travel of both left and right rudders.
 
Reading this and wondering about pilot technique?
Flying a number of gyros I adapt to the machine, for me there is no one sise fits all approach, in the Trojan where in some cases we have 320 Hp making the 915 look like a toy we are mindful with the throttle during the take of phaze.
I for one would not be comfortable with full rudder deflection from the outset, the Cavalon was built as a recreational aircraft and the client base would not have the exp of the war pilots used to high thrust machines like the P51 or similar.
With 300+ Hp the take off is a non event, prerotate, stick full back gradually apply power fwd roll commences front wheel lifts airspeed builds ( instantly adding rudder authority) then take power as needed, climb .

If we take a hand full of power the prop cavitates and offers little in thrust and torque it’s a feel one needs to develop and all part of learning that aircraft type, hence the conversion to type.
Not taking sides but adding I would not be comfortable putting the nose down ( unless only slightly during the initial take off phase) simply to raise airspeed but instructors saying put the nose down when your under full power with full rudder deflection is not a technique I have needed or used.
For me the Cavalon is no harder to fly than any other gyro ( it’s not my favourite either) but I doubt those arrogant Germans will have put a recreational aircraft to market that requires such drastic pilot inputs on take off? Without standing on toes it may be in the interest of 915 Cavalon owners to spend a few moments with a different instructor?

I have flown with a number of instructors during my short gyro career and from each one I have learnt something and based on that I try to do a renewal each year with a different instructor, rather than the same guy who could be ticking boxes and doing a flight renewal comfortable that I can fly because he knows me and possibly does not want to really pick on developed bad habits.
Flying with a different instructor may not be the most comfortable but it raises your skill set and offers a different dynamic and approach, after all for me it’s about being safe and enjoying the game
 
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When the installed power increases, then the P-factor becomes critical and it seems to me that it is up to the designers to deal with it, not the instructors.
They have several solutions to reduce or even eliminate it:
- Angular asymmetry of the vertical stabilizer in the propeller blast
- Angular asymmetry of the propeller axis
-Lateral offset of the propeller axis
- Centering of the rudder in the propeller wind
- Counter-rotating coaxial propellers

which ones did these designers implement?
 
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When the installed power increases, then the P-factor becomes critical and it seems to me that it is up to the designers to deal with it, not the instructors.
They have several solutions to reduce or even eliminate it:
- Angular asymmetry of the vertical stabilizer in the propeller blast
- Angular asymmetry of the propeller axis
-Lateral offset of the propeller axis
- Centering of the rudder in the propeller wind
- Counter-rotating coaxial propellers

which ones did these designers implement?

The ones usually used are offsetting the engine to one side or at a slight angle and rigging the rudder at an angle (to the right) I know that AutoGyro and Magni and us rig the rudder usually to the right. I am not sure if they need to use even more rudder input to the point that it hits the stops. In ours it does not. But I did notice that AutoGyro limits the travel to only 25 degrees to 30 degrees. We allow 45. That may have something to do with it. Airplanes will do 25 or 30 degrees but their rudders are located much farther behind.
 
I personally do not like the idea of having to use full rudder deflection to counteract full power on TO, unless, the prevailing conditions call for it.
In most cases runway length available, density altitude, TO weight and wind will allow for safe take off without use of max power, if, that power setting required full rudder deflection.

Most small/private FW will use full power for TO and are designed so that some rudder is used to counteract P factor. I have however been in a situation when doing a first flight in a single hole Pitts with a 200HP Lycoming. I had received a comprehensive briefing from the owner with an omission, he had failed to mention that if full power was used initially, full rudder would not keep it straight. But with a smooth steady increase in power that soon became obvious.

The airlines routinely use derated power for TO's, whenever possible, to minimise wear and tear on engines. "Derated" thrust is carefully calculated for each takeoff using weight altitude temps for the runway in use, the field climb requirements, and the airlines procedures and limits. It is generally below the maximum power available. In these cases there is no P factor or torque to cope with, however with multiple power plants, asymmetric thrust due to engine failure has to be considered, so rudder input and effectiveness remains and important consideration.

I do not have the knowledge to critique gyro design, but simply feel that if I flew a machine that required full application of any control surface to achieve a 'normal' take off, with nothing left for an abnormal gust of wind, it is not perhaps the best design.
 
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Reading this and wondering about pilot technique?
Flying a number of gyros I adapt to the machine, for me there is no one sise fits all approach, in the Trojan where in some cases we have 320 Hp making the 915 look like a toy we are mindful with the throttle during the take of phaze.
I for one would not be comfortable with full rudder deflection from the outset, the Cavalon was built as a recreational aircraft and the client base would not have the exp of the war pilots used to high thrust machines like the P51 or similar.
With 300+ Hp the take off is a non event, prerotate, stick full back gradually apply power fwd roll commences front wheel lifts airspeed builds ( instantly adding rudder authority) then take power as needed, climb .

If we take a hand full of power the prop cavitates and offers little in thrust and torque it’s a feel one needs to develop and all part of learning that aircraft type, hence the conversion to type.
Not taking sides but adding I would not be comfortable putting the nose down ( unless only slightly during the initial take off phase) simply to raise airspeed but instructors saying put the nose down when your under full power with full rudder deflection is not a technique I have needed or used.
For me the Cavalon is no harder to fly than any other gyro ( it’s not my favourite either) but I doubt those arrogant Germans will have put a recreational aircraft to market that requires such drastic pilot inputs on take off? Without standing on toes it may be in the interest of 915 Cavalon owners to spend a few moments with a different instructor?

I have flown with a number of instructors during my short gyro career and from each one I have learnt something and based on that I try to do a renewal each year with a different instructor, rather than the same guy who could be ticking boxes and doing a flight renewal comfortable that I can fly because he knows me and possibly does not want to really pick on developed bad habits.
Flying with a different instructor may not be the most comfortable but it raises your skill set and offers a different dynamic and approach, after all for me it’s about being safe and enjoying the game

Note: P factor is even worse for me in all aircraft so far, I only weigh 118 on a good week. When I fly a 300 lbs friend in the right see I can add full power and still have the rudder left on take-off leveling off. And do not have to move the cyclic to the left nearly as much and she will not climb out at anywhere near the angle of attack, reducing the p factor.

I agree. All of my instructors taught me to add full power and let her fly off and parallel the runway straight and level, without the climb they may have the right rudder authority while level gaining airspeed to Vx, I DO NOT with my weight. I only weigh 118 lbs on a good week. My instructors have all been less than 180, two are only 170. When I fly the Cavalon I still have torque roll at full power even leveling off. It only took 2 or 3 takeoffs in the Cavalon for me to tell the instructor. I'm at full right rudder from the start of rotation and I do not like being low to the ground at full stop. He said he did not realize that I was at full stop. I ask so I'm only going to only add 4900 to rotate and then 5500 to start my climb so I still have the right rudder left until I'm about 100 feet off the runway then I'll add full power and climb out at full throttle with right rudder to the stop as they all do. I also realized that I needed to learn how many RPM's I need to reduce power If I get hit by a gust of wind. It's 5300 RPM and practice this maneuver at least once each time I'm doing touch and goes. That's about every day if I'm not doing maintenance and weather permits.


So yes from 100 feet off the ground I was choosing to be in a max steep climb, as the instructor did. Yes, we are all at the full right rudder.
At 100 feet and full power, I've practiced reducing power as if hit by a gust of wind many many times. At 100 feet it is a non-event, in my opinion. Please explain where I'm wrong.

I just flew with a Friend that was trained at the same place and watched him recently and he flies with full power way before I do while leveling off just as all three instructors taught me. I think he is at full right rudder way before I am but not sure what he is feeling.
I do not add the same power when I fly with him until at 100 feet.
 
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I personally do not like the idea of having to use full rudder deflection to counteract full power on TO, unless, the prevailing conditions call for it.
In most cases runway length available, density altitude, TO weight and wind will allow for safe take off without use of max power, if, that power setting required full rudder deflection.

Most small/private FW will use full power for TO and are designed so that some rudder is used to counteract P factor. I have however been in a situation when doing a first flight in a single hole Pitts with a 200HP Lycoming. I had received a comprehensive briefing from the owner with an omission, he had failed to mention that if full power was used initially, full rudder would not keep it straight. But with a smooth steady increase in power that soon became obvious.

The airlines routinely use derated power for TO's, whenever possible, to minimise wear and tear on engines. "Derated" thrust is carefully calculated for each takeoff using weight altitude temps for the runway in use, the field climb requirements, and the airlines procedures and limits. It is generally below the maximum power available. I these cases there is no P factor or torque to cope with however with multiple power plants asymmetric thrust due to engine failure has to be considered so rudder input and effectiveness remains and important consideration.

I do not have the knowledge to critique gyro design, but simply feel that if I flew a machine that required full application of any control surface to achieve a 'normal' take off, with nothing left for an abnormal gust of wind, it is not perhaps the best design.
I do not like it either. If you read my first post I explain that. But I have now called a 4th instructor and only asked "are you at full stop on the right rudder taking off in the Cavalon? He said yes. I did not tell him what it is about. But seems at least 4 CFIs are not even teaching to reduce power until 100 feet as I did on my own??
 
John I think this may also come down to a Philosophy of takeoffs. The way I was taught and many of us were was to use just what we need for throttle for takeoff. Once in the air a few feet up let the nose lower and accelerate to optimal climb out speed and ease the stick back and maintain that speed with the stick. Most two places need full throttle to do that. My single place was powerful so I didn’t always need full throttle but I used it most of the time because I loved the fast climb. It looked like a zoom climb but I never let my speed die off and would enter a turn to maintain rotor rpm.
 
John I think this may also come down to a Philosophy of takeoffs. The way I was taught and many of us were was to use just what we need for throttle for takeoff. Once in the air a few feet up let the nose lower and accelerate to optimal climb out speed and ease the stick back and maintain that speed with the stick. Most two places need full throttle to do that. My single place was powerful so I didn’t always need full throttle but I used it most of the time because I loved the fast climb. It looked like a zoom climb but I never let my speed die off and would enter a turn to maintain rotor rpm.
I posted thinking with 3 instructors teaching that method, it must be all of them, and innocently posted what they are teaching and got commended by Vance and Jim. Blame the instructors, until your crying about it I did not know. I reduce the power setting on my own. I'm the only one who could feel I was at full stop in a Cavalon 915 even at straight and level at low airspeeds, not the instructor.
It is so much worse flying by myself. I fly her off at 4600 RPM and initial climb at 5300 in Cavalon 915s when flying alone. But at 100 feet I'm at full power and full right rudder. 100 feet is a lot of time to recover in a gyroplane especially when you are maintaining 80MPH climb.
 
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