Gyro Hover flight

[Volo]

A Question for the learned gyro fraternity.
I have always understood that a gyro can not hover unless the local wind speed Is above a certain value and definitely not in a no wind situation .

I have borrowed a remark from another thread set out below that says it can . Is the author wrong or has he/ she just forgotten about windspeed ?


..........................................

Not quite true. You can do a full power hover in a gyro, with no forward speed and without losing altitude. The gyro don't need speed, the rotor has enough speed to create lift. I don't think wind was an issue in this accident, from a rumour I heard, low clouds / mist.
These users thanked the author mak for the post (total 3):
Rotor kop • LASS 1190 • Carel
www.altairaviation.co.za
Home of Zen & Xenon Gyrocopters

[Rotor kop]

As far as i know to date there are no gyros that can hover indefinitely like a helicopter. In the right hands like of someone like Greg Vos it can for a second or 2 unless there is a wind as per your initial comment. Logically only a power driven rotor can sustain its power...

[Captain Gyro]

Correct, gyro’s cannot hover (although they like to call it hovering), but can fly at zero indicated airspeed, which results in a vertical descent.

If the wind is around 17 kts, a gyro can fly (1 up) such that the groundspeed is zero.

[Volo]

Thanks Captain - from what I understand the zero airspeed produces a vertical descent rate of as much as 1500 ft/ min and if maintained down to the ground at what amounts to a destructive outcome ?

[Rotor kop]

Correct, gyro’s cannot hover (although they like to call it hovering), but can fly at zero indicated airspeed, which results in a vertical descent.

If the wind is around 17 kts, a gyro can fly (1 up) such that the groundspeed is zero.

Thank you for the explanation Captain Gyro.

[Captain Gyro]

Volo, yes, with the thottle closed, at zero indicated airspeed, RoD goes up to 1 800ft/min. It’s a fun exercise to lose height, and is especially weird if you do it descending rapidly when small puffs of cloud are about (but within sight of the ground). It’s an experience fixed wing pilots don’t get to experience, feeling like you are in a lift descending quickly.

Because there is no collective, one has to come out of the hover or vertical descent around 300ft agl minimum and accelerate to one’s normal approach speed of around 60 mph to be then be able to arrest the descent in the flare.

[Volo]

Volo, yes, with the thottle closed, at zero indicated airspeed, RoD goes up to 1 800ft/min. It’s a fun exercise to lose height, and is especially weird if you do it descending rapidly when small puffs of cloud are about (but within sight of the ground). It’s an experience fixed wing pilots don’t get to experience, feeling like you are in a lift descending quickly.

Because there is no collective, one has to come out of the hover or vertical descent around 300ft agl minimum and accelerate to one’s normal approach speed of around 60 mph to be then be able to arrest the descent in the flare.

I presume coming out of the vertical descent is not accomplished by throttle or maybe partial throttle but more by stick forward - sorry yet another question ?

[Captain Gyro]

Absolutely, the stick is used primarily to lower the nose to build up the airspeed. Some throttle can be used to make things happen quicker, but the important aspect is that even with full power, below an indicated airspeed of around 25 mph (1 up), a gyro will still descend as it so far behind yhe power curve.

[mak]

Captain Gyro
I was the gyro pilot that made the comment and I know you have a lot of gyro hours, but unfortunately I don't quite agree with you. I did power hovers many years ago, but the one thing that always worried me was rotor decay while doing it.
This year at my renewal, I mentioned it to the instructor and was put at ease that it won't happen, still enough airflow over the rotor even while "hovering"
So we practised a few of them during my renewal. Wind was at most about 10mph, power setting obviously close to full throttle and stick almost full back, we probable hovered for +- 2 minutes without loosing altitude and zero airspeed.
You obviously have to keep your eye on engine temps and thats why we aborted after 2 minutes.
So definitely not indefinite hovering, but for a short period can be done and I will only do it at altitude or like the instructor said, if you are really in an emergency (last resort) and you do have full power available. That was the actual reason why we practised it.

[20048]

Gyro hovering!

This is like any potential "behind the power curve" discussion. All aircraft have a Power Available (remembering for how long) versus Power Required graph.

If you have (continuous) and ample available power (for any aircraft) you can climb!

I don't think many aircraft (apart from aerobatic or military!) will qualify, but some can for a while! Gyro's definately can hover for a while (however newer power plants are starting to show impressive continuous power available!!)

[jtresfon]

Depends on your definition of a hover.

If your definition is to hold a stationary position (relative to the ground) and maintain altitude, then yes, in the hands of a competent pilot a gyro can hover, but only into wind and given a fresh breeze (say 12-15kt or more for the sake of argument) and depending on the load carried. In a decent wind, a helicopter style hover landing can be achieved in a gyro, using the throttle to control the rate of descent. If the wind or the engine dies and you are under 300ft, this will not end well!

In a zero wind situation you can pull back on the stick until the airspeed gets to 0, and then the gyro will start to descend after a few seconds. The rate of descent will increase if power is removed, to over 1500ft/min with zero power and obviously somewhat less with power, but descend it will, even at wide open throttle. Hitting the ground in this attitude will not end well.

Arresting the descent is simple, lower the nose until flying speed is reached (roughly above 25mph one up or 40mph two up) and then add power as required to maintain altitude. Recovery from a hover descent is ALWAYS led with stick/pitch and not by adding power first, to avoid the chance of a bunt over.

A common misconception, even among some experienced gyro pilots, it that airspeed can affect rotor speed. This is simply not true and your rotor speed will not change whether flying at 80mph or at 0mph. Once in the air, the ONLY thing that changes rotor speed is the weight or G force. Pull more G's and the rotor is loaded and rotor speed increases. Negative G's result in the rotor unloading and therefore decreases rotor RPM, potentially with fatal consequences hence the banning of all negative G manoeuvres in gyros. There is NO rotor decay in a hover or vertical descent!

Another point is that airflow over the radiators is reduced while flying at zero airspeed and engine temps can climb quickly, especially if in a full power hover.

This video is a nice example of what gyros can achieve in a decent wind: https://youtu.be/2tXqWb63UdQ?si=tERBFyey0iOpN9Pc

Regards
Jean.

[Mike Wissing]

I can make a C172 and 182 fly at zero indicated airspeed too! Am I actually hovering?

[jtresfon]

I can make a C172 and 182 fly at zero indicated airspeed too! Am I actually hovering?

Really? Surely a fixed wing at zero indicated airspeed is stalled and falling/spinning? How can it be flying? Not being facetious, I'm geniunely curious?

Jean.

[Jean Crous]

I can make a C172 and 182 fly at zero indicated airspeed too! Am I actually hovering?

Really? Surely a fixed wing at zero indicated airspeed is stalled and falling/spinning? How can it be flying? Not being facetious, I'm geniunely curious?

Jean.

Jean, with a fixed wing a strong enough headwind, with a high power setting takes care of the forward movement over the ground. This coupled with a high enough angle of attack , just before stall, will give a pitot error enough so that it reads zero, or thereabouts, giving the illusion of zero indicated airspeed.
I have done this myself, as have other fixed wing pilots who like to "play".
J

[TC]

Really? Surely a fixed wing at zero indicated airspeed is stalled and falling/spinning? How can it be flying? Not being facetious, I'm geniunely curious? Jean.

Spoken like someone who’s never left a pitot cover on