All_In
Gold Supporter
- Joined
- Apr 21, 2008
- Messages
- 16,105
- Location
- San Diego, CA. USA
- Aircraft
- Airgyro AG915 Centurian, Aviomania G1sb
- Total Flight Time
- Gyroplane 70Hrs, not sure over 10,000+ logged FW, 260+ ultralights, sailplane, hang-gliders
Here is the first rough draft of the new section I will add to the rotorcraft aerodynamics presentation. Please help me get this right!
I've tried to express in correctly as I understand it in the simplest term I know now. Please feel free to pick it a part. That how I test my opinions and the only thing I do better than believing what I know is changing once show the error of my ways.
==== Start ===
Flying at or below minimum airspeed, and Fixed wing vs. Rotorcraft Stalls
During a banked turn the lift on the aircraft must support the weight of the aircraft, as well as provide the necessary NEW component of horizontal force to cause centripetal acceleration. Consequently, the lift required in a banked turn is greater than that one required in straight, level flight is by increasing the angle of attack. The maneuver is usually complemented by an increase in power, in order to maintain airspeed.
CLT and statically stable aircraft:
In all airfoil aircraft, not lighter than air aircraft, you must bring the nose up. With aircraft that are Center Line Trust and statically stable with respect to G-load it's necessary to use aft stick pressure to execute a level, banked turn at constant airspeed.
FW or rotorcraft both apply the laws of flight physics EXACTLY the same; All airfoil aircraft you must raise the nose, change pitch, of the aircraft in a banked turn, FW you raise the nose just a little even in a shallow turn.
Why because any moving vehicle or aircraft making a turn, it is necessary for the forces acting on the aircraft to add up to a NEW net inward force if you look at the picture there is a new horizontal force (centripetal acceleration) that is stealing some of your lift in a banked turn, examine the picture and see the yellow arrow. The more you bank the more it steals.
Same in a car this force is what makes you slide off the road in a turn.
The more weight you are carrying in a banked turn the more airspeed you need to counter the centripetal acceleration. Near stall airspeed, you REALLY need to learn what airspeed your aircraft needs to carry max gross weight thru any bank angle you may fly. Especially when low to the ground approaches to the airport when turning final. This is where many accidents occur and or turning low to the ground at slow airspeed on down wind turns.
Realize this will be at a much different and slower airspeed in a gyro than a FW for them to even be compared and only then once flying to slow and both pilots are in trouble.
The biggest differences between FW and rotorwing is the DRAG, the minimum safe airspeed difference is extreme, and in gyroplanes rotorblade ground taxi management and pre-rotation take-off procedures.
The drag you can see when you pull power noticing the GUIDE RATIO compared to FW. Gyro 4 to 1, FW 10 to 1 at least; that’s 25% of the lift of a fixed wing. Once in trouble you are going to have to add 4 times as much power OR 4 times as much changing the pitch to counter the exact SAME centripetal acceleration in rotorcraft however, rotorcraft flies often 4 time slower so it's harder to get in trouble compared to FW in this regard too and faster time to recover at a much slower safe airspeed in a gyro, although FW'er will notice a LAG to regain airspeed compared to FW on your first behind the power curve landing in a gyroplane. You should not be flying 20 knots an hour in a gyroplane or 45 to 60 knots in most small FW's (just an example).
Now raising the nose even a little is going to increase your angle of attack increasing DRAG so a turn at LOW AIR SPEEDS will always require more airspeed in any turn in both FW and Rotorwing.
This means it 4 times easier once you are in trouble in a gyroplane and 4 times harder to get out of trouble AT LOW AIR SPEEDS sort of 4 times the lag time compared to FW. JUST maintain the correct airspeed or do not turn = land straight ahead!
Rotorcraft also do not stall the same and sort of mush into the ground with less server impact compared to FW sort of like having too small of parachute see stalls below.
High Trust Line HTL you may not pull back on the stick and is different than CLT:
In some HTL, statically unstable gyros, though, the fore-aft stick pressure feedback with changing G-loads is apt to be reversed. In these craft, it's necessary to add FORWARD pressure to avoid mushing out of a turn, once you've settled into your bank. Newbies in Bensens used to mush out of turns all the time.
The need for forward stick to hold speed in a turn is one quick way to diagnose uncompensated HTL in a gyro. It's not foolproof; much depends on the trim spring rate, head offset, spring setup and a bunch of other variables.
The fact that a slowed-up gyro falls out of a turn in a mush while a slowed-up FW stalls and goes straight in is apt to be cold comfort to the aircraft's occupants. The pilots of both craft must go against every human instinct and get the stick forward to regain airspeed -- and tolerate the temporarily-increased rate of fall that this input causes. It takes guts -- and it may not work if the ground catches you before you do regain that speed.
Stall and FW vs Rotorcraft:
If you are flying at MINIMUM airspeed with a HEADWIND and turn downwind with a wind speed grater than 0 = What do you think is going to happen if you do not increase your airspeed by the exact or greater amount than minimum airspeed needed to counter centripetal acceleration to maintain altitude? You start and uncontrollable descend, and or stall and spin in a FW, until you either gain airspeed or hit the ground.
The gyro's advantage over the FW is not that it won't fall out of a turn in the absence of airspeed ('cause it will). Rather, the gyro mushes instead of freefalling, as the FW does. The gyro pilot still has full cyclic control; he just can't immediately arrest the descent. Moreover, the gyro mushes downward slower than a FW plane falls in stall -- so if worse comes to worst, the gyro will hit the ground at a speed and attitude that may be survivable.
The most important difference, though, IMHO, is that gyros don't lose lift on one side of their "wing" while maintaining it on the other -- IOW, they don't spin. FW planes, to various degrees, are spirally unstable and tent to tighten a banked turn, and to "lock in" to a spin. You can't just "high stick" your way out of a spin. The gyro has no tendency to tighten in the first place, and you can always "lift a wing" in a gyro by simply high-sticking. You don't have to "trick" the aircraft into leveling out with the use of rudder, as in a spinning FW.
The most vicious part of a stall-spin is the spin. We gyro folk are free of that monster -- though we still are bound by the need for airspeed.
It’s important to know that FW and rotorcraft stall differently and at much different airspeeds but the solution is exactly the same for both!
Airspeed... either more power or point the nose down to gain airspeed.
There are no other options!
However, over coming human nature to point at the ground when so close and looking right at it can only be over come with training at altitude so it's so automatic you don't even notice the ground only the airspeed indicator as you hit the ground.
JUST WATCH YOUR AIRSPEED INDICATOR and KNOW how much power you may need to add in a turn and if you need to pull your stick back or forward and this will not happen in either a FW or rotorwing aircraft!
Uncontrolled descents and stalls CANNOT happen with the correct airspeed no matter what the bank angle and the wind speed or direction with in reason.
===END---
A little help Doug?
I've tried to express in correctly as I understand it in the simplest term I know now. Please feel free to pick it a part. That how I test my opinions and the only thing I do better than believing what I know is changing once show the error of my ways.
==== Start ===
Flying at or below minimum airspeed, and Fixed wing vs. Rotorcraft Stalls
During a banked turn the lift on the aircraft must support the weight of the aircraft, as well as provide the necessary NEW component of horizontal force to cause centripetal acceleration. Consequently, the lift required in a banked turn is greater than that one required in straight, level flight is by increasing the angle of attack. The maneuver is usually complemented by an increase in power, in order to maintain airspeed.
CLT and statically stable aircraft:
In all airfoil aircraft, not lighter than air aircraft, you must bring the nose up. With aircraft that are Center Line Trust and statically stable with respect to G-load it's necessary to use aft stick pressure to execute a level, banked turn at constant airspeed.
FW or rotorcraft both apply the laws of flight physics EXACTLY the same; All airfoil aircraft you must raise the nose, change pitch, of the aircraft in a banked turn, FW you raise the nose just a little even in a shallow turn.
Why because any moving vehicle or aircraft making a turn, it is necessary for the forces acting on the aircraft to add up to a NEW net inward force if you look at the picture there is a new horizontal force (centripetal acceleration) that is stealing some of your lift in a banked turn, examine the picture and see the yellow arrow. The more you bank the more it steals.
Same in a car this force is what makes you slide off the road in a turn.
The more weight you are carrying in a banked turn the more airspeed you need to counter the centripetal acceleration. Near stall airspeed, you REALLY need to learn what airspeed your aircraft needs to carry max gross weight thru any bank angle you may fly. Especially when low to the ground approaches to the airport when turning final. This is where many accidents occur and or turning low to the ground at slow airspeed on down wind turns.
Realize this will be at a much different and slower airspeed in a gyro than a FW for them to even be compared and only then once flying to slow and both pilots are in trouble.
The biggest differences between FW and rotorwing is the DRAG, the minimum safe airspeed difference is extreme, and in gyroplanes rotorblade ground taxi management and pre-rotation take-off procedures.
The drag you can see when you pull power noticing the GUIDE RATIO compared to FW. Gyro 4 to 1, FW 10 to 1 at least; that’s 25% of the lift of a fixed wing. Once in trouble you are going to have to add 4 times as much power OR 4 times as much changing the pitch to counter the exact SAME centripetal acceleration in rotorcraft however, rotorcraft flies often 4 time slower so it's harder to get in trouble compared to FW in this regard too and faster time to recover at a much slower safe airspeed in a gyro, although FW'er will notice a LAG to regain airspeed compared to FW on your first behind the power curve landing in a gyroplane. You should not be flying 20 knots an hour in a gyroplane or 45 to 60 knots in most small FW's (just an example).
Now raising the nose even a little is going to increase your angle of attack increasing DRAG so a turn at LOW AIR SPEEDS will always require more airspeed in any turn in both FW and Rotorwing.
This means it 4 times easier once you are in trouble in a gyroplane and 4 times harder to get out of trouble AT LOW AIR SPEEDS sort of 4 times the lag time compared to FW. JUST maintain the correct airspeed or do not turn = land straight ahead!
Rotorcraft also do not stall the same and sort of mush into the ground with less server impact compared to FW sort of like having too small of parachute see stalls below.
High Trust Line HTL you may not pull back on the stick and is different than CLT:
In some HTL, statically unstable gyros, though, the fore-aft stick pressure feedback with changing G-loads is apt to be reversed. In these craft, it's necessary to add FORWARD pressure to avoid mushing out of a turn, once you've settled into your bank. Newbies in Bensens used to mush out of turns all the time.
The need for forward stick to hold speed in a turn is one quick way to diagnose uncompensated HTL in a gyro. It's not foolproof; much depends on the trim spring rate, head offset, spring setup and a bunch of other variables.
The fact that a slowed-up gyro falls out of a turn in a mush while a slowed-up FW stalls and goes straight in is apt to be cold comfort to the aircraft's occupants. The pilots of both craft must go against every human instinct and get the stick forward to regain airspeed -- and tolerate the temporarily-increased rate of fall that this input causes. It takes guts -- and it may not work if the ground catches you before you do regain that speed.
Stall and FW vs Rotorcraft:
If you are flying at MINIMUM airspeed with a HEADWIND and turn downwind with a wind speed grater than 0 = What do you think is going to happen if you do not increase your airspeed by the exact or greater amount than minimum airspeed needed to counter centripetal acceleration to maintain altitude? You start and uncontrollable descend, and or stall and spin in a FW, until you either gain airspeed or hit the ground.
The gyro's advantage over the FW is not that it won't fall out of a turn in the absence of airspeed ('cause it will). Rather, the gyro mushes instead of freefalling, as the FW does. The gyro pilot still has full cyclic control; he just can't immediately arrest the descent. Moreover, the gyro mushes downward slower than a FW plane falls in stall -- so if worse comes to worst, the gyro will hit the ground at a speed and attitude that may be survivable.
The most important difference, though, IMHO, is that gyros don't lose lift on one side of their "wing" while maintaining it on the other -- IOW, they don't spin. FW planes, to various degrees, are spirally unstable and tent to tighten a banked turn, and to "lock in" to a spin. You can't just "high stick" your way out of a spin. The gyro has no tendency to tighten in the first place, and you can always "lift a wing" in a gyro by simply high-sticking. You don't have to "trick" the aircraft into leveling out with the use of rudder, as in a spinning FW.
The most vicious part of a stall-spin is the spin. We gyro folk are free of that monster -- though we still are bound by the need for airspeed.
It’s important to know that FW and rotorcraft stall differently and at much different airspeeds but the solution is exactly the same for both!
Airspeed... either more power or point the nose down to gain airspeed.
There are no other options!
However, over coming human nature to point at the ground when so close and looking right at it can only be over come with training at altitude so it's so automatic you don't even notice the ground only the airspeed indicator as you hit the ground.
JUST WATCH YOUR AIRSPEED INDICATOR and KNOW how much power you may need to add in a turn and if you need to pull your stick back or forward and this will not happen in either a FW or rotorwing aircraft!
Uncontrolled descents and stalls CANNOT happen with the correct airspeed no matter what the bank angle and the wind speed or direction with in reason.
===END---
A little help Doug?
Attachments
Last edited: