Aussie_Paul
A reforming stirrer!!!!!
- Joined
- Oct 30, 2003
- Messages
- 4,441
- Location
- Ballarat Australia
- Aircraft
- None at the moment.
- Total Flight Time
- Since 1982 Gyro 5000+ mostly instructing, and approx. 200 fixed wing in the late 1960s.
I have searched my hard drive and found most of the relevant info re my "non understanding" of gyroplanes in 1982 to where I finished with Firebird late 2007, a little wiser and informed thanks to many on this forum.
Part 1. Written approx. early 2007
I started powered gyro flying in March 1982 with a Bensen style gyro fitted with a 1905 cc VW direct drive, a 53” two blade timber prop, and a set of solid spar 23’ Rota Hawk rotors. It had a Bensen rock guard and a horizontal stab. I had bought the keel with the fin, rudder, and h/stab already fitted. I think the guys’ wife made him sell it!!! My dad and I reckoned I might as well leave the stab on even though Bensen did not have a stab. I learnt to fly it first by towing. Hops were next followed by circuits. I conducted 350 hours of most enjoyable flying in this machine between 1982 and 1987.
The death rate started to climb as the Rotax with the redrive came along and people were able to get above ground effect before they lost control and died. Prior to this a lot of alloy was bent but not a great many deaths. By the time people had the skill to get above ground effect they had enough skill not to PIO and bunt to their deaths.
I decided to try and do something about dual training and after sorting out a home built machine I imported an Air Command side x side 532 powered trainer with 25” Mc Cutchen Skywheel rotors. Gyro training was illegal in Oz at that time and my legal advisers felt that if I was going to help people train in gyros, while attempting to have the rules changed, it would be better to be operating a commercially made machine rather than a home built in case something terrible happened. If there had not been people dying in these quick build A/Command HTL kits, I would have fought to have the rules changes before I began offering training.
My first student was a friend, Mark, who was fed up with the GA rules etc and decided to build a 503 single seat open frame. With single ignition and insufficient rotor blade area I began training with hops as people had been doing with the gyro glider. We would fly from one end to the other, back track and do it again. People had to learn to taxi and valuable briefing chats were had whilst back tracking. In nil wind fly both ways. Mark was over controlling badly in pitch as did most fixed wing pilots starting with gyros. I remembered seeing a pic of a single seat A/Command with a pod and h/stab fitted, so that night I made a similar looking flat plate stab from what I could remember from the pic. I placed it 1/3 of the way up the all flying tail.
The next night we went out again and low and behold Mark was flying s/level ok!!! While refueling I removed the stabs and Mark went back to over controlling!!! Today I still have those stabs hanging up in the shed for sentimental reasons.
At this time I believed that gyros were more like a helicopter and you had to fly them all the time. I fitted the A/c super thruster update kit that had a 68” prop instead of the standard 60”. This improved the static thrust by 25 lbs with this update. Next I had the opportunity to buy 27’ Skywheel rotors and fit a dual ignition 582. This, with fitting an in flight adjustable pitch trim, made the machine less marginal and safe in my mind to conduct training away from the runway. My hand never left the throttle and many times I felt that the student would die if I wasn’t there to stop the “bunt over”!!!! Ignorance was bliss as well as being very very scared of dying probably kept me alive. The need to help people over rode my fear of dying. Around February 1990 I was President of ASRA and with help from people like mceagle Tim we achieved legal dual place training.
I took an ex Vietnam chopper pilot, who was part of the Oz air accident investigating team, for a fly in this trainer and he commented that it would be absolutely impossible to learn to fly a gyroplane without heaps of training. He came and spent an hour training with me so he could understand more about gyroplanes. He sometimes had to investigate gyroplane accidents. It was nice having the govt give me some of my taxes back!!!!! I eventually conducted a little over 1500 dual training hours in this old A/C trainer that I called “old faithful”.
As I have said in previous posts, 1997 was the time for a change and I looked at Raf for a comfortable dual trainer, and Raf were looking for an experienced instructor who believed in good instruction. At this time I still believed that gyros where inherently unstable and had to flown all the way!!! I argued with Don, from Raf, about the lack of an h/stab. Don convinced me the “magic bush come control geometry” scenario was the pitch stability stabiliser. People who said that my Raf did not have a stab would get the “magic bush come control geometry” scenario!!!!
Geez, I am embarrassed to admit all of this!!!!
I first flew the Raf in the winter and conducted quite a few 200 and 300 mile cross countries. As the summer thermals started to develop I began enjoying this flying less!!!! I would be exhausted after a few hours in the middle of a hot summer’s day. Not even game to take my hand off the throttle for a drink!!!!
In 1999 three months after being at Bensen days with Raf, I had the opportunity to fly with Rob Sanders in NZ in his Raf with a stab. When I trained Rob in my A/Command I told him of the stab story. I had heard that Rob was playing with stabs. Rob told me that he had a fright in his Raf in rough NZ mountain waves and remembered my H/stab story. He decided to have a go at making one, and proved how much better the Raf was with a stab. I was so impressed with Robs Raf that I rang Raf and was read the riot act. They (Don the flower) said that Rob and I did not know what we were talking about. I told Don that I was going to proceed to test h/stabs on my Raf, and was hoping for support.
I arrived home and told my brother Lin, who was now a proficient Raf pilot, about the Robs Raf. I made a stab to Rob’s dimensions out of ¼” ply with some alloy supports. Robs was ¾” thick and non flexible. Lin and I went flying and I was disappointed with my stab. We could feel it starting to work, but flexing the thinner ply, but the Raf kept trying to PPO. The next few days had me making one out of 5/8” MDF. Now we had a stab that was working similar to Robs.
Rob had told me about Norm’s forum and it was at this time I was the newbie on the forum and very much a Raf supporter. I explained what I was doing with the Raf, and people howled the company down and said that the stab was a band aid. I got defensive and argued BUT could see the sense that Chuck Beaty was making with his “pushing on the pencil” scenario. I am glad that I can change my views when needed!!! We made various stabs with Retro Composites Alan Loughrey, and ended up with an airfoil shaped stab that Alan called the “effective” stab. Alan improved the effective stab further by using negative AoA with it. Also at this time Ken J was introducing the Rob Sanders stab to the market place. Ken beat us to the market by a few months if I remember correctly. These were exciting days. It was strange to see diehard Raf supporters giving up on the company and going separate ways. Testing various stabs I would see how far I could fly without touching the stick. I would use power to help and realized that my abilities at sensing the unloading of the rotor were clouding the testing. A number of test pilots made some comments on the forum and emailed me privately to help me learn how to conduct unbiased testing. When you are testing your own product you want it to work and it is easy to unintentionally “fool” yourself. It took me quite some time to be able to test correctly so that I could learn from the data gained.
My brother Lin bought a kit and we decided to see if Chuck Beaty really did know what he was talking about!!!! It made sense to me BUT I always like to prove things to myself.
We decided to swap the Raf 8” off set belt redrive and fit a 4” off set Hirth gearbox BUT mount it with the prop line higher than the engine crankshaft. We stepped the keel 4” and because Raf has too much prop to keel clearance we were able to lower the thrust line 5”. This meant that the engine was now 7” higher and the thrust line 5” lower. It looked so terrible and unusual after the Raf!!! We had to make new tail feathers because the prop was rotating in the opposite direction with the gearbox. Knowing that the Raf is yaw unstable with the doors on we decided to make the tail 30% larger. This fixed the yaw stability problems. We also had to move the axle back several inches because with the almost CLT arrangement the nose came up so early that steering was difficult and putting the stick forward enough to place the nose wheel back on the ground there was insufficient disc angle to speed up the rotors.
This was the birth of Hybrid. I had been thinking about Firebird because I was having no joy with Raf and safety issues. That is why we decided to test Chucks (and many others of course) theory. Chuck’s patience with me was probably more than I deserved but Chuck hung in there for me.
Hybrid without a stab flew better than the stabbed Raf, and once we fitted a stab to hybrid. WOW!!!!
I began stick free, followed by stick fixed stability testing. Changing the trimmed airspeed by 10% and seeing how many times the nose went through the horizon and how long it took Hybrid to return to trimmed condition. The Hybrid stabs were adjustable, so I conducted tests at various AoA. I also tested various sizes and shapes of stabs on Hybrid, tested various thrust line angles as well as developing a system in my hanger for me to be able to use the double hang picture method to find the CoM of gyros. Every gyro that comes to my hanger has the CoM measured. This is for my benefit and that of the owner.
This would have to rate as the most exciting part of my aviation career. This uneducated country bumpkin was actually proving the theory. By now we were getting a pretty good handle on what was needed to make a stable gyroplane.
The next challenge was to try and improve Rafs without having to fit a gearbox which necessitated a new fin and rudder, or fitting what I felt was a reasonably expensive AAI augmentation kit. I conducted some stick fixed stability testing in a Raf with a stab to see what we needed to improve on. Attempting to conduct stick fixed testing was more like: "The first bump and the machine would start to diverge in pitch". That was the only time I felt uncomfortable with stick fixed testing. I tried twice more but the same thing happened each time. It was fine until the first bump.
I figured that getting the thrust line down by 6” must be a help, but the weight of the engine and redrive would also come down. I then figured that the rest of the gross weight of the Raf would go up in relation to the thrust line. With the engine weight of approx 300 lbs and the gross weight 1200 lbs I figured, rightly or wrongly, the CoM should change approx. 30%. 30% of the stock Raf offset of 10” was 3”, so I felt that this would be a worthwhile exercise. I modified my first stock Raf without changing the redrive or tail feathers. I also lowered the front of the engine to give a 3 degree down of the thrust line.
The first problem was the tail wheel was too low and there was not enough rotation. I had to angle the rear stepped keel back up at approx. 3 degrees to put the tail wheel back to its original position. This further helped the fixed pitch h/stab by giving it 3 more degrees of Negative AoA. The next problem encountered was the fact that the nose wheel lifted too early and the stick had to be pushed so far forward to place the nose wheel back on the ground. The disc angle was so low that the rotors were very slow to come up. Solo, I would just let it sit on the tail wheel until it flew off.
Two NZ friends, John and Lloyd, who I had trained a few years earlier bought a Raf NZ registered RAE and asked me how to modify it. John came up with the idea of curving the keel under the prop and then curving it back up to the original position. This was very aesthetic. I told john to make sure he included 3 degrees negative AoA with the stab. I also mentioned to john that I was in the process of moving the axle back a few inches on one Raf, but we could do that when I arrived to conduct the flight testing. The flight testing went well except for the nose coming up too early problem. The next day was wet so we moved the axle back a few inches and we had another WOW!!!
During the next couple of weeks I conducted training in the most modified Raf I had flown, and people who had trained with me earlier in my stabbed Raf could really notice the difference. I had a stick the correct length that I could fit between the control stick and the dash to hold 60 mph s/level cruise speed. I would remove the stick and pull the nose up until the speed was 50 mph, then I would lock the control stick again, and the machine would settle back to the stick locked trim speed after 15 seconds and 3 passes of the nose through the horizon. With an increase in speed it would take slightly longer to return to stick locked trim speed. I was happy BUT there was still one thing missing and that was the yaw stability that I had gotten used to with Hybrid.
In June 2005 while I was grounded in Oz, I again went to NZ to help out with training. John and Lloyd had fitted fuel injection to their Raf and John had modified another Raf RCW for its owner. This Raf had a larger adjustable stab with an airfoil section, as well fins on the ends of the stabs. John had also lengthened the rear keel enough to move the fin, rudder and stab back 8”. This was now the most modified Raf that I had flown, other than Hybrid.
I ran a 10 hour flight testing program with a NZ testing officer as my passenger and scribe for the testing. The pitch stability exceeded the NZ fixed wing standard. Once again I was a very happy chappy!!!!!
If I was building a stock Raf with a stab I would move the axle back 2”. With the extra weight of a stab out the back the nose wheel does come up too early particularly when solo and low fuel.
The final chapter will be to see if I have been able to incorporate all that I have learnt, with the above testing, into Firebird Mk1.
In a few months we should know!!!!
I realize that this has turned into a bit of an epistle, BUT there is a very productive story in amongst it all.
Aussie Paul.
Part 1. Written approx. early 2007
I started powered gyro flying in March 1982 with a Bensen style gyro fitted with a 1905 cc VW direct drive, a 53” two blade timber prop, and a set of solid spar 23’ Rota Hawk rotors. It had a Bensen rock guard and a horizontal stab. I had bought the keel with the fin, rudder, and h/stab already fitted. I think the guys’ wife made him sell it!!! My dad and I reckoned I might as well leave the stab on even though Bensen did not have a stab. I learnt to fly it first by towing. Hops were next followed by circuits. I conducted 350 hours of most enjoyable flying in this machine between 1982 and 1987.
The death rate started to climb as the Rotax with the redrive came along and people were able to get above ground effect before they lost control and died. Prior to this a lot of alloy was bent but not a great many deaths. By the time people had the skill to get above ground effect they had enough skill not to PIO and bunt to their deaths.
I decided to try and do something about dual training and after sorting out a home built machine I imported an Air Command side x side 532 powered trainer with 25” Mc Cutchen Skywheel rotors. Gyro training was illegal in Oz at that time and my legal advisers felt that if I was going to help people train in gyros, while attempting to have the rules changed, it would be better to be operating a commercially made machine rather than a home built in case something terrible happened. If there had not been people dying in these quick build A/Command HTL kits, I would have fought to have the rules changes before I began offering training.
My first student was a friend, Mark, who was fed up with the GA rules etc and decided to build a 503 single seat open frame. With single ignition and insufficient rotor blade area I began training with hops as people had been doing with the gyro glider. We would fly from one end to the other, back track and do it again. People had to learn to taxi and valuable briefing chats were had whilst back tracking. In nil wind fly both ways. Mark was over controlling badly in pitch as did most fixed wing pilots starting with gyros. I remembered seeing a pic of a single seat A/Command with a pod and h/stab fitted, so that night I made a similar looking flat plate stab from what I could remember from the pic. I placed it 1/3 of the way up the all flying tail.
The next night we went out again and low and behold Mark was flying s/level ok!!! While refueling I removed the stabs and Mark went back to over controlling!!! Today I still have those stabs hanging up in the shed for sentimental reasons.
At this time I believed that gyros were more like a helicopter and you had to fly them all the time. I fitted the A/c super thruster update kit that had a 68” prop instead of the standard 60”. This improved the static thrust by 25 lbs with this update. Next I had the opportunity to buy 27’ Skywheel rotors and fit a dual ignition 582. This, with fitting an in flight adjustable pitch trim, made the machine less marginal and safe in my mind to conduct training away from the runway. My hand never left the throttle and many times I felt that the student would die if I wasn’t there to stop the “bunt over”!!!! Ignorance was bliss as well as being very very scared of dying probably kept me alive. The need to help people over rode my fear of dying. Around February 1990 I was President of ASRA and with help from people like mceagle Tim we achieved legal dual place training.
I took an ex Vietnam chopper pilot, who was part of the Oz air accident investigating team, for a fly in this trainer and he commented that it would be absolutely impossible to learn to fly a gyroplane without heaps of training. He came and spent an hour training with me so he could understand more about gyroplanes. He sometimes had to investigate gyroplane accidents. It was nice having the govt give me some of my taxes back!!!!! I eventually conducted a little over 1500 dual training hours in this old A/C trainer that I called “old faithful”.
As I have said in previous posts, 1997 was the time for a change and I looked at Raf for a comfortable dual trainer, and Raf were looking for an experienced instructor who believed in good instruction. At this time I still believed that gyros where inherently unstable and had to flown all the way!!! I argued with Don, from Raf, about the lack of an h/stab. Don convinced me the “magic bush come control geometry” scenario was the pitch stability stabiliser. People who said that my Raf did not have a stab would get the “magic bush come control geometry” scenario!!!!
Geez, I am embarrassed to admit all of this!!!!
I first flew the Raf in the winter and conducted quite a few 200 and 300 mile cross countries. As the summer thermals started to develop I began enjoying this flying less!!!! I would be exhausted after a few hours in the middle of a hot summer’s day. Not even game to take my hand off the throttle for a drink!!!!
In 1999 three months after being at Bensen days with Raf, I had the opportunity to fly with Rob Sanders in NZ in his Raf with a stab. When I trained Rob in my A/Command I told him of the stab story. I had heard that Rob was playing with stabs. Rob told me that he had a fright in his Raf in rough NZ mountain waves and remembered my H/stab story. He decided to have a go at making one, and proved how much better the Raf was with a stab. I was so impressed with Robs Raf that I rang Raf and was read the riot act. They (Don the flower) said that Rob and I did not know what we were talking about. I told Don that I was going to proceed to test h/stabs on my Raf, and was hoping for support.
I arrived home and told my brother Lin, who was now a proficient Raf pilot, about the Robs Raf. I made a stab to Rob’s dimensions out of ¼” ply with some alloy supports. Robs was ¾” thick and non flexible. Lin and I went flying and I was disappointed with my stab. We could feel it starting to work, but flexing the thinner ply, but the Raf kept trying to PPO. The next few days had me making one out of 5/8” MDF. Now we had a stab that was working similar to Robs.
Rob had told me about Norm’s forum and it was at this time I was the newbie on the forum and very much a Raf supporter. I explained what I was doing with the Raf, and people howled the company down and said that the stab was a band aid. I got defensive and argued BUT could see the sense that Chuck Beaty was making with his “pushing on the pencil” scenario. I am glad that I can change my views when needed!!! We made various stabs with Retro Composites Alan Loughrey, and ended up with an airfoil shaped stab that Alan called the “effective” stab. Alan improved the effective stab further by using negative AoA with it. Also at this time Ken J was introducing the Rob Sanders stab to the market place. Ken beat us to the market by a few months if I remember correctly. These were exciting days. It was strange to see diehard Raf supporters giving up on the company and going separate ways. Testing various stabs I would see how far I could fly without touching the stick. I would use power to help and realized that my abilities at sensing the unloading of the rotor were clouding the testing. A number of test pilots made some comments on the forum and emailed me privately to help me learn how to conduct unbiased testing. When you are testing your own product you want it to work and it is easy to unintentionally “fool” yourself. It took me quite some time to be able to test correctly so that I could learn from the data gained.
My brother Lin bought a kit and we decided to see if Chuck Beaty really did know what he was talking about!!!! It made sense to me BUT I always like to prove things to myself.
We decided to swap the Raf 8” off set belt redrive and fit a 4” off set Hirth gearbox BUT mount it with the prop line higher than the engine crankshaft. We stepped the keel 4” and because Raf has too much prop to keel clearance we were able to lower the thrust line 5”. This meant that the engine was now 7” higher and the thrust line 5” lower. It looked so terrible and unusual after the Raf!!! We had to make new tail feathers because the prop was rotating in the opposite direction with the gearbox. Knowing that the Raf is yaw unstable with the doors on we decided to make the tail 30% larger. This fixed the yaw stability problems. We also had to move the axle back several inches because with the almost CLT arrangement the nose came up so early that steering was difficult and putting the stick forward enough to place the nose wheel back on the ground there was insufficient disc angle to speed up the rotors.
This was the birth of Hybrid. I had been thinking about Firebird because I was having no joy with Raf and safety issues. That is why we decided to test Chucks (and many others of course) theory. Chuck’s patience with me was probably more than I deserved but Chuck hung in there for me.
Hybrid without a stab flew better than the stabbed Raf, and once we fitted a stab to hybrid. WOW!!!!
I began stick free, followed by stick fixed stability testing. Changing the trimmed airspeed by 10% and seeing how many times the nose went through the horizon and how long it took Hybrid to return to trimmed condition. The Hybrid stabs were adjustable, so I conducted tests at various AoA. I also tested various sizes and shapes of stabs on Hybrid, tested various thrust line angles as well as developing a system in my hanger for me to be able to use the double hang picture method to find the CoM of gyros. Every gyro that comes to my hanger has the CoM measured. This is for my benefit and that of the owner.
This would have to rate as the most exciting part of my aviation career. This uneducated country bumpkin was actually proving the theory. By now we were getting a pretty good handle on what was needed to make a stable gyroplane.
The next challenge was to try and improve Rafs without having to fit a gearbox which necessitated a new fin and rudder, or fitting what I felt was a reasonably expensive AAI augmentation kit. I conducted some stick fixed stability testing in a Raf with a stab to see what we needed to improve on. Attempting to conduct stick fixed testing was more like: "The first bump and the machine would start to diverge in pitch". That was the only time I felt uncomfortable with stick fixed testing. I tried twice more but the same thing happened each time. It was fine until the first bump.
I figured that getting the thrust line down by 6” must be a help, but the weight of the engine and redrive would also come down. I then figured that the rest of the gross weight of the Raf would go up in relation to the thrust line. With the engine weight of approx 300 lbs and the gross weight 1200 lbs I figured, rightly or wrongly, the CoM should change approx. 30%. 30% of the stock Raf offset of 10” was 3”, so I felt that this would be a worthwhile exercise. I modified my first stock Raf without changing the redrive or tail feathers. I also lowered the front of the engine to give a 3 degree down of the thrust line.
The first problem was the tail wheel was too low and there was not enough rotation. I had to angle the rear stepped keel back up at approx. 3 degrees to put the tail wheel back to its original position. This further helped the fixed pitch h/stab by giving it 3 more degrees of Negative AoA. The next problem encountered was the fact that the nose wheel lifted too early and the stick had to be pushed so far forward to place the nose wheel back on the ground. The disc angle was so low that the rotors were very slow to come up. Solo, I would just let it sit on the tail wheel until it flew off.
Two NZ friends, John and Lloyd, who I had trained a few years earlier bought a Raf NZ registered RAE and asked me how to modify it. John came up with the idea of curving the keel under the prop and then curving it back up to the original position. This was very aesthetic. I told john to make sure he included 3 degrees negative AoA with the stab. I also mentioned to john that I was in the process of moving the axle back a few inches on one Raf, but we could do that when I arrived to conduct the flight testing. The flight testing went well except for the nose coming up too early problem. The next day was wet so we moved the axle back a few inches and we had another WOW!!!
During the next couple of weeks I conducted training in the most modified Raf I had flown, and people who had trained with me earlier in my stabbed Raf could really notice the difference. I had a stick the correct length that I could fit between the control stick and the dash to hold 60 mph s/level cruise speed. I would remove the stick and pull the nose up until the speed was 50 mph, then I would lock the control stick again, and the machine would settle back to the stick locked trim speed after 15 seconds and 3 passes of the nose through the horizon. With an increase in speed it would take slightly longer to return to stick locked trim speed. I was happy BUT there was still one thing missing and that was the yaw stability that I had gotten used to with Hybrid.
In June 2005 while I was grounded in Oz, I again went to NZ to help out with training. John and Lloyd had fitted fuel injection to their Raf and John had modified another Raf RCW for its owner. This Raf had a larger adjustable stab with an airfoil section, as well fins on the ends of the stabs. John had also lengthened the rear keel enough to move the fin, rudder and stab back 8”. This was now the most modified Raf that I had flown, other than Hybrid.
I ran a 10 hour flight testing program with a NZ testing officer as my passenger and scribe for the testing. The pitch stability exceeded the NZ fixed wing standard. Once again I was a very happy chappy!!!!!
If I was building a stock Raf with a stab I would move the axle back 2”. With the extra weight of a stab out the back the nose wheel does come up too early particularly when solo and low fuel.
The final chapter will be to see if I have been able to incorporate all that I have learnt, with the above testing, into Firebird Mk1.
In a few months we should know!!!!
I realize that this has turned into a bit of an epistle, BUT there is a very productive story in amongst it all.
Aussie Paul.
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