Gyrocopters/Autogyros
If you push the stick to quick/fast forward the rotor stops
I have some hours in gyro“s. They are great fun to fly but that big rotor windmilling creates a horrendous drag which costs power to overcome.
In some ways the gyro is the best and worst of both worlds. It has the simplicity of airplane and manueverability of the helicopter but it also is expensiver to run than airplane and slower but yet still does not do what a helicopter can do.
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Gyros
There are only 70 or so gyros operating inthe UK (ie they have a current permit to fly). Most are single seaters powered by 2-stroke Rotax engines (so the McCulloch thing is a red herring).
There are lots of reasons why they aren't more popular in the UK, for example:
You can't (as of today) purchase a factory built machine. You either have to build one yourself (eek!) or buy one used which someone else has built (double eek!)
They have a poor safety record. None of the aircraft flying up to now in the UK have been approved to any engineering standard, they are all old designs with approvals based on "service experience". As a result many have some undesirable handling characteristics which make them vulnerable to mishandling. The poor accident record has made our regulators nervous about approving new designs or changes to old ones, which makes it very expensive and time consuming. This discourages people form innovating or building modern, safe machines - so the existing problems are perpetuated.
Because demand is low (due partly to the lack of aircraft) most people have to travel a long way to get to an instructor - much further than to learn on microlights or fixed wing, so the bar is raised once again.
Gyro cost more than microlights - used single-seat gyros have typically be selling in the £7k to £10k range. For that money you could get a decent 2-seat flex wing.
The good nbews is that it's all starting to change. The Magni M16 (see earlier in the thread) is finally approaching approval, and the MT-03 (www.rotorsport.org) has completed all its testing and is in the final throes of the approval process (mine is due any day now!). With safe factory built machines available gyros are likely to become much more popular, though they will always remain a niche. That said, the MT-03 was the second largest selling microlight in Germany last year, and seems to be very popular with pilots looking for something different.
So why do we fly them? Because they are huge, huge fun. They are manouverable, have a wide speed range, draw a crowd wherever you go and make a fantastic "woc-woc" noise as you pull "g" - what more could you want?
For more info take a look at the British Rotorcraft Association website www.gyroplanes.org
There are lots of reasons why they aren't more popular in the UK, for example:
You can't (as of today) purchase a factory built machine. You either have to build one yourself (eek!) or buy one used which someone else has built (double eek!)
They have a poor safety record. None of the aircraft flying up to now in the UK have been approved to any engineering standard, they are all old designs with approvals based on "service experience". As a result many have some undesirable handling characteristics which make them vulnerable to mishandling. The poor accident record has made our regulators nervous about approving new designs or changes to old ones, which makes it very expensive and time consuming. This discourages people form innovating or building modern, safe machines - so the existing problems are perpetuated.
Because demand is low (due partly to the lack of aircraft) most people have to travel a long way to get to an instructor - much further than to learn on microlights or fixed wing, so the bar is raised once again.
Gyro cost more than microlights - used single-seat gyros have typically be selling in the £7k to £10k range. For that money you could get a decent 2-seat flex wing.
The good nbews is that it's all starting to change. The Magni M16 (see earlier in the thread) is finally approaching approval, and the MT-03 (www.rotorsport.org) has completed all its testing and is in the final throes of the approval process (mine is due any day now!). With safe factory built machines available gyros are likely to become much more popular, though they will always remain a niche. That said, the MT-03 was the second largest selling microlight in Germany last year, and seems to be very popular with pilots looking for something different.
So why do we fly them? Because they are huge, huge fun. They are manouverable, have a wide speed range, draw a crowd wherever you go and make a fantastic "woc-woc" noise as you pull "g" - what more could you want?
For more info take a look at the British Rotorcraft Association website www.gyroplanes.org
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Aesir,
Most of the drag seen by the current recreational gyros is induced drag.
Max L/D on an autorotating rotor occurs at ~35% of peripheral tip speed. My gyro rotor spins about 340 RPM, for a tip speed of 410 fps. Max L/D is about 143 fps, or 97 mph.
Above that, profile and parasitic rotor drag starts picking up.
Unfortunately due to my Bensen's airframe drag, I can't even touch Max L/D . I top out at about 85 mph.
More streamilined machines could likely cruise at their most efficient rotor speed though. Andy Keech routinely cruises above 90 mph in his Little Wing gyro.
The previously mentioned studies highlight the importance of thrustline-to-CG relationship, and gyro designs have been moving back in that direction. I say back because this was something that Cierva had figured out in the early days of autogyros, and is just being rediscovered.
My opinion on the poor safety record of the early Bensen gyros is that:
As for the later designs, many 'designers' just raised the mast and rotor, and slapped a Rotax on the back with it's larger diameter propeller.
Instant thrustline offset.
And usually no horizontal stabilizer was installed to counteract it, or to stabilize the airframe.
I have flown a couple of these types and they are a handful.
But this is what I am currently building:
http://www.rotorflightdynamicsinc.com
And they fly like they're supposed to.
That's actually me in the first picture on the main page.
Most of the drag seen by the current recreational gyros is induced drag.
Max L/D on an autorotating rotor occurs at ~35% of peripheral tip speed. My gyro rotor spins about 340 RPM, for a tip speed of 410 fps. Max L/D is about 143 fps, or 97 mph.
Above that, profile and parasitic rotor drag starts picking up.
Unfortunately due to my Bensen's airframe drag, I can't even touch Max L/D . I top out at about 85 mph.
More streamilined machines could likely cruise at their most efficient rotor speed though. Andy Keech routinely cruises above 90 mph in his Little Wing gyro.
The previously mentioned studies highlight the importance of thrustline-to-CG relationship, and gyro designs have been moving back in that direction. I say back because this was something that Cierva had figured out in the early days of autogyros, and is just being rediscovered.
My opinion on the poor safety record of the early Bensen gyros is that:
- There were no dual trainers to get instruction in. You had to teach yourself.
- Bensen did not incorporate a proper horizontal stabilizer in his design. Without a horizontal stab, the pilot can end up in a Pilot Induced Oscillation (PIO) because of the lag and overshoot inherent in a teetering rotor system, possibly unloading the rotors. Add in an offset thrustline and the machine can begin an unrecoverable tumble. The addition of a horizontal stab can tame quite a bit of thrust offset in addition to minimizing lag and overshoot.
My Bensen has one.
As for the later designs, many 'designers' just raised the mast and rotor, and slapped a Rotax on the back with it's larger diameter propeller.
Instant thrustline offset.
And usually no horizontal stabilizer was installed to counteract it, or to stabilize the airframe.
I have flown a couple of these types and they are a handful.
But this is what I am currently building:
http://www.rotorflightdynamicsinc.com
And they fly like they're supposed to.
That's actually me in the first picture on the main page.
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Gyromike,
Is there any advantage in autogyro of a 3-blade articulated or even rigid head rotor? This would get around many of the reduced-g control loss problems, and elastomeric bushes are widely available (ie cheap lead/lag hinges possible). I remember being told about an ex-Westlands guy doing some work at Bristol uni - but it may have only ever remained theory...
I'm also puzzled why a teetering gyro seems easier to fly than say an R22. Is this just due to the direct control system, or does less rotor mass help? I'm a fan of the '60s Lockheed gyro system, but am now wondering if there is some inherent advantage to being in permanent autorotation...
Mart
Is there any advantage in autogyro of a 3-blade articulated or even rigid head rotor? This would get around many of the reduced-g control loss problems, and elastomeric bushes are widely available (ie cheap lead/lag hinges possible). I remember being told about an ex-Westlands guy doing some work at Bristol uni - but it may have only ever remained theory...
I'm also puzzled why a teetering gyro seems easier to fly than say an R22. Is this just due to the direct control system, or does less rotor mass help? I'm a fan of the '60s Lockheed gyro system, but am now wondering if there is some inherent advantage to being in permanent autorotation...
Mart
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Originally Posted by Graviman
Gyromike,
Is there any advantage in autogyro of a 3-blade articulated or even rigid head rotor? This would get around many of the reduced-g control loss problems, and elastomeric bushes are widely available (ie cheap lead/lag hinges possible). I remember being told about an ex-Westlands guy doing some work at Bristol uni - but it may have only ever remained theory...
I'm also puzzled why a teetering gyro seems easier to fly than say an R22. Is this just due to the direct control system, or does less rotor mass help? I'm a fan of the '60s Lockheed gyro system, but am now wondering if there is some inherent advantage to being in permanent autorotation...
Mart
Is there any advantage in autogyro of a 3-blade articulated or even rigid head rotor? This would get around many of the reduced-g control loss problems, and elastomeric bushes are widely available (ie cheap lead/lag hinges possible). I remember being told about an ex-Westlands guy doing some work at Bristol uni - but it may have only ever remained theory...
I'm also puzzled why a teetering gyro seems easier to fly than say an R22. Is this just due to the direct control system, or does less rotor mass help? I'm a fan of the '60s Lockheed gyro system, but am now wondering if there is some inherent advantage to being in permanent autorotation...
Mart
A multi-bladed head would provide 'head moment' to be able to maintain attitude during low G events. There have been a few one-offs built over the years, also the McCulloch J2 and Air & Space 18A gyros.
The 2-bladed teetering systems are just simpler and less costly.
But it's not the rotors that are causing the problems. It's the unstable framework underneath.
Eliminate the thrustline offset, and use generous tail surfaces, and even 0 G events are a non-issue (provided you aren't flying into tornados and such).
If you use a a full-span vertical stabilizer in addition to the horizontal to help eliminate torque roll and slipstream yaw with power changes, you can reduce the dangers caused by unloading the rotors. During a momentary unloading of the rotors, the aircraft will continue to track into the relative wind while the rotors reload. The problems occur when you are using rotor thrust to counteract rolling and pitching forces caused by the unstable airframe.
The Dominator that I linked to above actually has a slightly low thrustline which will tend to raise the nose in a low G event, helping to reload the rotors.
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Serious thanks, Gyromike! This makes very good sense. Would there be any advantage in having vertical & horizontal stabilisers as part of the control system? This just gives pilot an additional level of reduced g control.
I guess blade strike is never going to be an issue since you are directly controling rotor disk attitude. I imagine this has a slight reduction in response delay over teetering too. The real advantage is there is not going to be any complication due to flapback, the compensation for which is why teetering machines end up being so sensitive.
How do you find the cyclic forces with direct rotor control though? Would it be fair to comment that an equivalent teetering gyro could out manouvre a teetering heli?
Mart
I guess blade strike is never going to be an issue since you are directly controling rotor disk attitude. I imagine this has a slight reduction in response delay over teetering too. The real advantage is there is not going to be any complication due to flapback, the compensation for which is why teetering machines end up being so sensitive.
How do you find the cyclic forces with direct rotor control though? Would it be fair to comment that an equivalent teetering gyro could out manouvre a teetering heli?
Mart
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Wallis Days
For anyone who's interested in autogyros the BRA Wallis Days event at Shipdham on 12th & 13th August is the place to go.
More details on www.gyroplanes.org
Hope to see you there.
More details on www.gyroplanes.org
Hope to see you there.
Brings back Nightmares these things do!
While a Civil Air Patrol cadet growing up....we had gyrocopters about the squadron grounds. The training copter was sat on a platform built on the rear of a pickup truck and secured loosely by chains so the aircraft could rise about a foot off the platform as the pickup truck drove down the taxiway providing the wind to drive the rotor.
The trick was to keep the copter centered over the platform while motoring down the taxiway.
Small bit of info was left out of the two minute brief by the instructor....that being "don't pull against the chains!"
Two of us nubbins strapped in and had our first gyrocopter training flight....each teaching the other.
About halfway down the trail....we managed to slightly overstress the rotor blades to the extent that one went walkies quite suddenly and without not much fanfare. The remaining blade opened up a huge can of whoop ass and spilled it all over the two of us, the pickup and anything within striking distance.
No broken bones but the pickup definitely had seen better days, the copter was a write off and we two budding aviators looked like we had each gone a dozen rounds with Mike Tyson, Mo Ali, Cutworm Smith, and a couple of other thugs.
That one "flight" cured me of gyrocopters.
Later as an instructor, when asked by a gyrocopter pilot to sign off a Biennial Flight Review, I would very politely but firmly tell them, not only would I not....but I would deny ever having met him.
The trick was to keep the copter centered over the platform while motoring down the taxiway.
Small bit of info was left out of the two minute brief by the instructor....that being "don't pull against the chains!"
Two of us nubbins strapped in and had our first gyrocopter training flight....each teaching the other.
About halfway down the trail....we managed to slightly overstress the rotor blades to the extent that one went walkies quite suddenly and without not much fanfare. The remaining blade opened up a huge can of whoop ass and spilled it all over the two of us, the pickup and anything within striking distance.
No broken bones but the pickup definitely had seen better days, the copter was a write off and we two budding aviators looked like we had each gone a dozen rounds with Mike Tyson, Mo Ali, Cutworm Smith, and a couple of other thugs.
That one "flight" cured me of gyrocopters.
Later as an instructor, when asked by a gyrocopter pilot to sign off a Biennial Flight Review, I would very politely but firmly tell them, not only would I not....but I would deny ever having met him.
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Originally Posted by SASless
Small bit of info was left out of the two minute brief by the instructor....that being "don't pull against the chains!"
Mart
Last edited by Graviman; 16th Jul 2006 at 09:39.
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Flying an autogyro (video)
For those with good connection this may be interesting to see: low-altitude piloting in our new open frame 2-seat tandem named "Twist" at sea shore.
Video (63 Mb of *.mpeg video) is here:
http://www.epilator.ru/trocadrive2.mpg
Aircraft itself can be seen in details at http://www.rotorcraft.ru
Cheers,
Video (63 Mb of *.mpeg video) is here:
http://www.epilator.ru/trocadrive2.mpg
Aircraft itself can be seen in details at http://www.rotorcraft.ru
Cheers,
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Cheezy soundtrack
Nice vid - but the soundtrack on the vid on www.rotorsport.org (follow the "Video" link) out-cheezes yours by an order of magnitude!
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Autogyro's/ Gyrocopters??
Hello there,
I would be grateful for any information at all on Autogyro's.
Recommendations for tuition and schools and also personal experiences would help.
Also looking for information from people that have their own machines. What would you recommend?
Is it possible to use a school's machine to do your solo work or do you have to have your own machine already by then?
I already have a PPL fixed wing but the spinning rotors fascinate me.
Thanks in advance for taking the time to reply.
Cheers
HJ
I would be grateful for any information at all on Autogyro's.
Recommendations for tuition and schools and also personal experiences would help.
Also looking for information from people that have their own machines. What would you recommend?
Is it possible to use a school's machine to do your solo work or do you have to have your own machine already by then?
I already have a PPL fixed wing but the spinning rotors fascinate me.
Thanks in advance for taking the time to reply.
Cheers
HJ
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The Original Whirly
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I did a trial lesson and a bit more - about an hour and a half total - in gyrocopters some years back. I thought they might be a cheaper alternative for a helicopter addict...but I decided they wouldn't do and went for my CPL(H) instead. They are, however, great fun - a mixture of f/w and rotary flying that I really enjoyed.
If you do a search you'll probably find more up-to-date info than I can give. Back then, there were only 7 instructors in the UK. I went to Roger Savage at Carlisle. I wasn't impressed, but that was mainly for personal reasons; he virtually asked me if my husband knew I was out, and implied that as a mere woman I couldn't possibly have earned enough money to pay for my own flying!!! I decided I couldn't learn from someone like that.
There is a chap somewhere in the South-West who has his own machine and own website who was incredibly helpful, as are all the (tiny) gyrocopter community, in my extremely limited experience. Again, Google can probably help.
You might want to note that gyrocopters don't have a good safety record. Most people think that this is due to lack of regulation in the past, but no-one is certain. And engineering types who know far more than I do about such things say not to touch the extremely pretty RAF 200 with a bargepole - definite stability problems, I believe.
Hopefully you'll get some more definite info soon.
If you do a search you'll probably find more up-to-date info than I can give. Back then, there were only 7 instructors in the UK. I went to Roger Savage at Carlisle. I wasn't impressed, but that was mainly for personal reasons; he virtually asked me if my husband knew I was out, and implied that as a mere woman I couldn't possibly have earned enough money to pay for my own flying!!! I decided I couldn't learn from someone like that.
There is a chap somewhere in the South-West who has his own machine and own website who was incredibly helpful, as are all the (tiny) gyrocopter community, in my extremely limited experience. Again, Google can probably help.
You might want to note that gyrocopters don't have a good safety record. Most people think that this is due to lack of regulation in the past, but no-one is certain. And engineering types who know far more than I do about such things say not to touch the extremely pretty RAF 200 with a bargepole - definite stability problems, I believe.
Hopefully you'll get some more definite info soon.