Mountain & Thermic Day Flying

[RogerB]

Hi All,
I'm new to Gyro's but have 17 years flying and racing Paragliders, 3 years in Paramotors, 40 hours in Sail Planes & just shy of 15 hours working towards my PPL in a Cessna 172 to then get my Gyro add-on - my main interest is back country & mountain flying.

Mountains:
Is there anything different about flying Gyro's in the mountains compared to other types of flying like a bushplane in terms of best/safest practice? Any rules of thumb you would suggest from experience?

Thermal Flying/ Clouds:
If flying at or near cloud base under clouds that are working on thermic days are there any tips, items to be cautious of or best practices to stay out of trouble? Is there a risk of the rotor going negative/negative G in strong enough thermals or with thermals that have sharp edges?
I just know you can get jolted around in sailplanes if your coming out of thermal or cutting through them or get collapses on paragliders if the day is strong enough coming into or out of strong thermals.

Cheers ,
Roger

 

[Tyger]

I can't speak to mountain flying, but gyros are generally a lot more comfortable to fly in turbulent air than fixed-wing aircraft.
There have been many, many brilliantly clear but blustery days I have flown when all the local airplanes seemed to be staying on the ground.
I have been in some pretty hefty up- and down-drafts, without seeing any alarming change in rotor rpm. You just get that strong up and down feeling, as if you're in a fast building elevator... or riding on a yo-yo.

 

[Resasi]

Have only experienced strong/severe turbulence in turbine aircraft...and once in a DC3. I have flown in gusty winds exceeding 20kts in a Bensen and been bounced quite a bit around but no concerns...however ignorance can be bliss, I had no way of knowing RRPM on that machine.

I am however aware that while in charter flying in Kenya a twin Comanche that flew into a thunderstorm was disintegrated, and a BOAC 707 flying round Mt Fujiyama was disintegrated midair by a vertical rotor, so there are catastrophic wind events that can destroy even very large aircraft.

In general however I would go with what Tyger said.

 

[Vance]

Hi All,
I'm new to Gyro's but have 17 years flying and racing Paragliders, 3 years in Paramotors, 40 hours in Sail Planes & just shy of 15 hours working towards my PPL in a Cessna 172 to then get my Gyro add-on - my main interest is back country & mountain flying.

Mountains:
Is there anything different about flying Gyro's in the mountains compared to other types of flying like a bushplane in terms of best/safest practice? Any rules of thumb you would suggest from experience?

Thermal Flying/ Clouds:
If flying at or near cloud base under clouds that are working on thermic days are there any tips, items to be cautious of or best practices to stay out of trouble? Is there a risk of the rotor going negative/negative G in strong enough thermals or with thermals that have sharp edges?
I just know you can get jolted around in sailplanes if your coming out of thermal or cutting through them or get collapses on paragliders if the day is strong enough coming into or out of strong thermals.

Cheers ,
Roger

Gyroplanes like airplanes are not all the same Roger.

Some will do better in turbulence than others.

Some have plenty of excess power; some don’t.

Some have generous rudder authority and some don’t.

I can make a hundred and eighty degree turn in a gyroplane with a much smaller radius than most fixed wing aircraft.

I feel most rules of thumb about mountain flying for fixed wing aircraft apply to gyroplanes.

I stay away from clouds with a lot of vertical development in a gyroplane.

I stay well clear of virga in a gyroplane.

I wish you all the best on your gyroplane adventure and welcome to the Rotary Wing Forum.

 

[WaspAir]

I think I recall an incident not too long ago in Utah in which a well known and experienced pilot with local knowledge was forced down on the lee side of high terrain. The message I take from that is that the much discussed ability to handle high winds and moderate turbulence will not help if you ignore the general rules about reading the winds, approach angle for ridges, extra altitude needed, having a plan B, etc.

I would be especially careful about staying well clear of standing wave rotor clouds. I would not expect a teetering rotor gyroplane to survive the energetic rotor turbulence that we often get here on the downwind side of the Rockies. I have seen a Super Cub come home with more dihedral, and asymmetrically so, in the wings, than when it left, and saw a metal glider with the spar so bent that the normally removable wings couldn't be removed for trailering (that glider was a total loss and the pilot was lucky to have lived). Caution and respect for the atmosphere is essential.

That said, I would be less worried about thermal conditions, although I would give cloudbase a big vertical margin. Generally, I have found that you can linger in lift and skedaddle out of sink and enjoy the ride.

 

[RogerB]

I think I recall an incident not too long ago in Utah in which a well known and experienced pilot with local knowledge was forced down on the lee side of high terrain. The message I take from that is that the much discussed ability to handle high winds and moderate turbulence will not help if you ignore the general rules about reading the winds, approach angle for ridges, extra altitude needed, having a plan B, etc.

I would be especially careful about staying well clear of standing wave rotor clouds. I would not expect a teetering rotor gyroplane to survive the energetic rotor turbulence that we often get here on the downwind side of the Rockies. I have seen a Super Cub come home with more dihedral, and asymmetrically so, in the wings, than when it left, and saw a metal glider with the spar so bent that the normally removable wings couldn't be removed for trailering (that glider was a total loss and the pilot was lucky to have lived). Caution and respect for the atmosphere is essential.

That said, I would be less worried about thermal conditions, although I would give cloudbase a big vertical margin. Generally, I have found that you can linger in lift and skedaddle out of sink and enjoy the ride.

Thanks for that

Aren’t all Gyroplane rotors teetering?

One of my favorite places to be is cloud base from my thermalling days - just wondering if that’s a big deal on a gyro or do you guys just stay to the adage of clouds like I do in a paramotor if you want to play with them? Should be fine in earlier morning late evening days without over development I reckon right?

How did the Utah guy end up in the Lee, must have been really strong wind or Venturi for the gyro not to be able to beat it?? What was the outcome?

So what is the likely hood of a rotor going negative on a thermic day in general, it seems like from the replies it would need to be wave conditions or thunderstorm level clouds for it to be catastrophic on a gyro rotor?

 

[WaspAir]

The rotor in my avatar picture is 3- bladed, fully articulated (rare, but there are some, and I have owned several).

The cloud separation requirement under VFR rules is pretty minimal for safety if some Cessna (or Learjet) on an IFR plan drops out the bottom. Your own upward visibility sucks under big cumulus, and most gyros are hard to spot from airplane cockpits. In the west, thermal strength can be enough to suck you up pretty rapidly and vertical development can be hard to see when you're up close and personal. If you stick to hot air balloon-friendly weather, you'll have no issues, but few limit themselves that way.

Downdrafts on the lee side of a big ridge or mountain obstruction can be quite capable of overpowering your best climb performance, and if you are coming from a valley, your room to escape may be insufficient. In the Utah case, IIRC injuries were minimal but aircraft damage was significant. He was attempting to cross a ridge in the upwind direction.

I am generally not worried about thermally induced negative g. However, both wave and cu-nimb conditions are capable of trashing a gyro with fatal results.

 

[Vance]

How did the Utah guy end up in the Lee, must have been really strong wind or Venturi for the gyro not to be able to beat it?? What was the outcome?

So what is the likely hood of a rotor going negative on a thermic day in general, it seems like from the replies it would need to be wave conditions or thunderstorm level clouds for it to be catastrophic on a gyro rotor?

If you are flying out of Telluride, Colorado near maximum takeoff weight and approach the lee side of a ridge at a slight angle with more than twenty five knots of wind you may not have the climb performance to get over the ridge or the ability to get away from the rotor caused by the ridge before hitting something.

I was not there.

More information is available reading about mountain wave activity.

I feel an understanding of mountain waves is an important part of flying anything in the mountains.

I have been unable to achieve less than . 6 Gs or slightly more than 2 Gs in the most extreme flying in my gyroplane. The .6 Gs was momentary and caused a 13% drop in rotor rpm.

I have not encountered environmental conditions that caused less than .8 Gs.

Not all gyroplanes are the same.

 

[okikuma]

I think I recall an incident not too long ago in Utah in which a well known and experienced pilot with local knowledge was forced down on the lee side of high terrain. The message I take from that is that the much discussed ability to handle high winds and moderate turbulence will not help if you ignore the general rules about reading the winds, approach angle for ridges, extra altitude needed, having a plan B, etc.

I would be especially careful about staying well clear of standing wave rotor clouds. I would not expect a teetering rotor gyroplane to survive the energetic rotor turbulence that we often get here on the downwind side of the Rockies. I have seen a Super Cub come home with more dihedral, and asymmetrically so, in the wings, than when it left, and saw a metal glider with the spar so bent that the normally removable wings couldn't be removed for trailering (that glider was a total loss and the pilot was lucky to have lived). Caution and respect for the atmosphere is essential.

That said, I would be less worried about thermal conditions, although I would give cloudbase a big vertical margin. Generally, I have found that you can linger in lift and skedaddle out of sink and enjoy the ride.

I really cannot improve on what JR has written. He is correct on all accounts.

Wayne

 

[Henry_GyroLife]

Hi Roger, I assumed your statement "flying at or near cloud base under clouds" is similar to "clear of clouds". Several years ago, FAA eliminated all class G airspace and made them to class E airspace in US, except below 1,200 AGL (some ares is 700AGL). This means you can't fly "clear of clouds" above 1,200AGL. You need to maintain the distance from clouds, 500 feet below, 1000 feet above and 2000 horizontally in class E airspace, in order to maintain safe distance from IFR traffic.

 

[Mayfield]

Several years ago, FAA eliminated all class G airspace and made them to class E airspace in US, except below 1,200 AGL (some ares is 700AGL).

Hi Henry,

I was unaware of this.

On my current Phoenix sectional, there is class G airspace, from the surface to 14,500, just east of Springerville, AZ. Southwest of Dryden, TX, is another such area.

I agree these areas are certainly becoming rare.

Jim

 

[Henry_GyroLife]

Hi Henry,

I was unaware of this. Does this mean the class G airspace, from the surface to 14,500, just east of Springerville, AZ, on my current Phoenix sectional, or the one southwest of Dryden, TX, are misprints?

I agree these areas are certainly becoming rare.

Jim

Wow, you are right. It still exists !! FAA eliminated all of them except the one you pointed. Do you know any reason they kept it ?

 

[Mayfield]

Wow, you are right. It still exists !! FAA eliminated all of them except the one you pointed. Do you know any reason they kept it ?

I don't know why those areas are left, but I don't think they are all that remain. I believe there are probably some pretty big areas in Alaska that still have class G up to 14,500.

I think you are correct on the trend though. Just a few years ago there was a section of class G to 14.5 just west of Page, AZ. It's gone now.

Jim

 

[Mayfield]

This means you can't fly "clear of clouds" above 1,200AGL. You need to maintain the distance from clouds, 500 feet below, 1000 feet above and 2000 horizontally in class E airspace, in order to maintain safe distance from IFR traffic.

Henry,

I apologize.

I focused on the second sentence in your post 10 above, and didn't appreciate the larger, and more important, point you were making. In class G airspace above 1200 AGL, but below 10,000 MSL, the flight visibility required is 1 SM, but the cloud clearance requirement is 500 below, 1000 above, and 2000 horizontal as you indicate.

Although you may have missed the few remaining areas where class G extends above 1200 agl, you were correct in your advice to Roger.

Jim

 

[ventana7]

I would echo what Wasp Air and my fellow mountain flyers said and add a few pointers. After you get your FW rating take a mountain flying course.
In my limited paragliding experience we packed up and hiked down in winds that would be moderate for a gyroplane so your go-no go decision wind limit might go up in FW and gyro flying. If you do decide to fly in stronger winds than you would have in a paraglider you need to also be prepared for the significant lee side vertical windshear you will experience. In the rockies it is very possible that 15 knots from the west will create downdrafts on the east side that exceed your machine's ability to climb- thus you need lots of extra altitude crossing ridges and always an out.

 

[Doug Riley]

Vance's comment that some gyros will do better than others in turbulence is an understatement. Gyros designed around the knowledge of stability that we had up to about 20 years ago (and not updated) require special techniques to avoid loss of control in turbulence.

Many (not all) such older designs had limited or no horizontal stabilizer power, coupled with fuselage layouts that created a significant nose-down bias.* As long as the rotor is creating thrust that is near, at, or above 1G, then the rotor thrust will hold the nose up against this nose-down bias. In the event of a sharp reduction of rotor thrust, however, this trimming effect is lost, and the nose will dip significantly with no pilot input. This can start a self-amplifying forward flip that can be unrecoverable. It also can trigger pilot-induced oscillation (PIO) in pitch, leading ultimately to the same deadly forward flip.

The special techniques needed to prevent this catastrophe in a vulnerable gyro are (1) power reduction and (2) a very loose grip on the stick (sometimes known as "floating").

A gyro with adequate horizontal stabilizer power does not require stick-floating. In fact, it will fly better in turbulence if the pilot uses a normal control grip.
_________________________
* This built-in bias around the pitch axis is attributable to a propeller thrustline located well above the gyro's CG and/or draggy components located well below its CG.

 

[ventana7]

Vance's comment that some gyros will do better than others in turbulence is an understatement. Gyros designed around the knowledge of stability that we had up to about 20 years ago (and not updated) require special techniques to avoid loss of control in turbulence.

Many (not all) such older designs had limited or no horizontal stabilizer power, coupled with fuselage layouts that created a significant nose-down bias.* As long as the rotor is creating thrust that is near, at, or above 1G, then the rotor thrust will hold the nose up against this nose-down bias. In the event of a sharp reduction of rotor thrust, however, this trimming effect is lost, and the nose will dip significantly with no pilot input. This can start a self-amplifying forward flip that can be unrecoverable. It also can trigger pilot-induced oscillation (PIO) in pitch, leading ultimately to the same deadly forward flip.

The special techniques needed to prevent this catastrophe in a vulnerable gyro are (1) power reduction and (2) a very loose grip on the stick (sometimes known as "floating").

A gyro with adequate horizontal stabilizer power does not require stick-floating. In fact, it will fly better in turbulence if the pilot uses a normal control grip.
_________________________
* This built-in bias around the pitch axis is attributable to a propeller thrustline located well above the gyro's CG and/or draggy components located well below its CG.

I flew my Sparrowhawk 10,000+ miles visiting all 48 states in the Continental US and whenever I looked ahead and saw a bunch of huge windmills I knew I was in for a wild ride. The two worst places I had for wind were Tehacapi pass heading up to Mojave and my very last day of flying to finish the trip near St. George, Utah with very strong gusty winds and canyons and rock outcrop terrain making it worse.

Just short of Mojave the gyro was being flipped on it's side as if I was in a 90 degree bank- but it was entirely wind shear causing it. When that happened I did what I had learned from my first gyro instructor in Australia- Alan Wardell who was a Quantas 747 senior check airman in his spare time. Alan had taught me to literally fly by the seat of my pants. You can feel the G forces making you light in the seat before you hear it in the rotor or see it on any instrument. If you act with stick movement to increase the G forces- you instantly feel that too. After awhile it is second nature. The action you take with the stick will be dependent on what is happening with the gyro but it is usually increasing bank to add G. Also the action you take with the stick will have a faster result than reducing power- though reducing power should also be part of the equation.

Rob

 

[Kevin_Richey]

...Just short of Mojave the gyro was being flipped on it's side as if I was in a 90 degree bank- but it was entirely wind shear causing it.
Rob

 

[Burrengyro]

I flew my Sparrowhawk 10,000+ miles visiting all 48 states in the Continental US and whenever I looked ahead and saw a bunch of huge windmills I knew I was in for a wild ride. The two worst places I had for wind were Tehacapi pass heading up to Mojave and my very last day of flying to finish the trip near St. George, Utah with very strong gusty winds and canyons and rock outcrop terrain making it worse.

Just short of Mojave the gyro was being flipped on it's side as if I was in a 90 degree bank- but it was entirely wind shear causing it. When that happened I did what I had learned from my first gyro instructor in Australia- Alan Wardell who was a Quantas 747 senior check airman in his spare time. Alan had taught me to literally fly by the seat of my pants. You can feel the G forces making you light in the seat before you hear it in the rotor or see it on any instrument. If you act with stick movement to increase the G forces- you instantly feel that too. After awhile it is second nature. The action you take with the stick will be dependent on what is happening with the gyro but it is usually increasing bank to add G. Also the action you take with the stick will have a faster result than reducing power- though reducing power should also be part of the equation.

Rob

Hi Rob, Could you expand a bit more on how you dealt with your gyro being flipped on it's side in turbulent wind conditions and wind shear and how you dealt with the event? If the gyro was flipped on it's port side, what exactly did you do to recover? How high were you? Did the rotor turning direction have an effect? Would a flip to starboard be handled differently? Many thanks for sharing. John H.

 

[ventana7]

Hi Rob, Could you expand a bit more on how you dealt with your gyro being flipped on it's side in turbulent wind conditions and wind shear and how you dealt with the event? If the gyro was flipped on it's port side, what exactly did you do to recover? How high were you? Did the rotor turning direction have an effect? Would a flip to starboard be handled differently? Many thanks for sharing. John H.

Well clearly the goal is to get the gyro right side up so if the gyro gets flipped to the right side down you want to bank left so you get right side up. Getting tossed on your side might or might not include getting light in the seat. If you don't get light in the seat indicating less than 1 G, I'm not sure there is any particular danger in getting thrown sideways. Just correct it to get straight and level. And in those conditions I would also make sure I had lots of altitude and not worry too much about maintaining a certain altitude or airspeed.

The other danger in gusty conditions is an updraft that makes you feel light in the seat indicating you have a less than 1G condition and the rotor is going to slow down- that IS dangerous and you should do something like banking to increase the G force. I am not sure every gyro responds the same so I'll leave it to Vance or other CFI who fly lots of different machines to answer in more detail.
Rob