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![]() Has anyone seen, or read about, that Skycycle? http://www.thebutterflyllc.com/sscycle/gallery.htm http://javimoya.com/blog/youtube_en.php http://www.thebutterflyllc.com/sscycle/images/002.jpg http://www.thebutterflyllc.com/sscycle/images/012.jpg http://www.thebutterflyllc.com/sscycle/images/001.jpg http://www.thebutterflyllc.com/sscycle/images/010.jpg -- boB copter.six |
#2
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![]() Has anyone seen, or read about, that Skycycle? http://www.thebutterflyllc.com/sscycle/images/010.jpg Well as everybody knows.... I'm just a little lurker, armchair pilot, and always stand to be corrected..... BUT.... Everything that I've ever read about gyros in this group always comes back to the fact that if it does not have a centre line stab the machine is prone to bunt over. Too bad Kenny Sandy Eggo isn't around these days because he is very knowleageble on the subject. He's been flying gyros for years. If you look at the Jpgs posted in the URL you will see how low the stab is on these machines. If I bought one of those I'd raise the stab up to be in line with the centre line of the engine. |
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Shiver wrote:
Well as everybody knows.... I'm just a little lurker, armchair pilot, and always stand to be corrected..... BUT.... Everything that I've ever read about gyros in this group always comes back to the fact that if it does not have a centre line stab the machine is prone to bunt over. Too bad Kenny Sandy Eggo isn't around these days because he is very knowleageble on the subject. He's been flying gyros for years. If you look at the Jpgs posted in the URL you will see how low the stab is on these machines. If I bought one of those I'd raise the stab up to be in line with the centre line of the engine. Thanks.. I had read something about that earlier. I haven't seen any recent articles about this thing and was hoping someone here had flown one. There's no reference to any owners of the skycycle on their page. I wonder if they have sold any. -- boB copter.six |
#4
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![]() "Shiver" wrote in message ... Has anyone seen, or read about, that Skycycle? http://www.thebutterflyllc.com/sscycle/images/010.jpg Well as everybody knows.... I'm just a little lurker, armchair pilot, and always stand to be corrected..... BUT.... Everything that I've ever read about gyros in this group always comes back to the fact that if it does not have a centre line stab the machine is prone to bunt over. Actually, it's not the stab that needs to be center line, it's the thrust line of the engine and prop. Having said all that, it is generally considered preferable, at least from what I've read, to have he horizontal stab in the prop wash. The idea being that the added air velocity will improve the stabs stabilizing effect. I'm not sure I agree with that 100% but I do agree that the horizontal stab is very import and should not be dismissed as trivial. You'll still run into folks every now and then that will claim the h-stab isn't needed on a gyro. On a pusher style gyro, the engine thrust line should (ideally) be as close to the vertical CG of the aircraft as possible. Many designs that have been put out in past years had an engine thrust line that was some distance above the vertical CG. That would induce a forward pitching moment. This force was countered by the rearward inclination of the main rotor and as long as you kept the main rotor loaded, everything balanced out and was fine. If the pilot ever unloaded the rotor while under power, the forces involved would not balance out and the aircraft was pitch forward (a bunt over, aka "power push over") and the pilot would quickly find himself inverted and out of options. Too many folks died this way. These days, most manufacturers of any note are only producing centerline thrust, or near centerline thrust gyros. Check out http://www.aircommand.com and look at the designs of their single and two place machine. Then do a search on "Air Command" and find pictures of their older designs. The difference in the location of the engines thrust line relative to the rest of the machine is dramatic. I've always been very impressed that Air Command undertook this redesign of their product line in the interest of flight safety. Some manufacturers have refused to do this for fear of liability issues. It would be like admitting there was something wrong with their older designs. At any rate, Air Command sells a retrofit kit to convert their older designs into the new centerline thrust model and recommends that the older bird not be flown until that modification is done. If you haven't seen it before, check out http://www.rotaryforum.com/index.php. It's a discussion forum on experimental rotorcraft and has lot's of good information on gyroplanes. About the only down side to this one is that many of these guys have "very" strong personalities and can be "very" opinionated. This means that sometimes you have to wade through a lot of egos to get to the meaningful information but if you're serious about getting into gyroplanes, it's well worth the effort. FWIW! :-) Too bad Kenny Sandy Eggo isn't around these days because he is very knowleageble on the subject. He's been flying gyros for years. Agreed! Good luck & Fly Safe, Steve R. |
#5
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Steve R wrote:
On a pusher style gyro, the engine thrust line should (ideally) be as close to the vertical CG of the aircraft as possible. Many designs that have been put out in past years had an engine thrust line that was some distance above the vertical CG. That would induce a forward pitching moment. This force was countered by the rearward inclination of the main rotor and as long as you kept the main rotor loaded, everything balanced out and was fine. If the pilot ever unloaded the rotor while under power, the forces involved would not balance out and the aircraft was pitch forward (a bunt over, aka "power push over") That sounds similar to my MX Sprint II back when I was instructing (see note) out of Charping field near Temple Texas. The thrust was quite a bit higher than the vertical CG. Cutting the throttle caused the nose to pitch up but it was just something a person had to be aware of. If you haven't seen it before, check out http://www.rotaryforum.com/index.php. It's a discussion forum on experimental rotorcraft and has lot's of good information on gyroplanes. About the only down side to this one is that many of these guys have "very" strong personalities and can be "very" opinionated. This means that sometimes you have to wade through a lot of egos to get to the meaningful information but if you're serious about getting into gyroplanes, it's well worth the effort. Good luck & Fly Safe, Steve R. Thanks again Steve. I did visit the rotary forum once. I think I'll try again but you all are pretty knowledgeable here. -- boB copter.six |
#6
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boB: I know a little bit about the Butterfly thing. The 4th picture down
on the left of the first website listed is a picture of me in my crack hat sitting on the Super SkyCycle. I met Larry Neal, the SkyCycle designer a number of years ago when we were producing the Popular Rotorcraft Magazine. Larry had just acquired the job of Test Pilot of the Carter Copter, which BTW, he successfully flew to an airspeed exceeding Mu 1. Larry is a very ethical guy and a very knowledgeable gyro pilot and designer. I have watched him demonstrate that landing gear of his by stopping the gyro about 10' in the air and letting it come down on its own from losing blade speed. He adds throttle and takes off again to repeat the maneuver. I believe that if Larry gives you a performance spec about his machine, you can take it to the bank. If I was going to go back to the gyro flying, his ship would be the first in line for me. BTW squared, In the process of doing the PRA magazine we met and spent some time with Comander Ken Wallis who is the UK gyro king. He did all of the flying for the James Bond movie that had the "Little Nellie" gyro. He doesn't share the statements that both horizontal stabilizers and center line thrust are a must. At least in his experience, and I might add mine (both my wife and I self taught in a Benson back in the late 60s and never dinged the ship and flew in a variety of conditions). This is not to say that some ships with an abundance of body work forward of the mast can't benefit from both things tho. I think that the two seat side-by-side gyros like the RAF and Sparrohawk would certainly fly different in gusty winds than the skimpy single seat Benson that I used to fly. -- Stuart Fields Experimental Helo magazine P. O. Box 1585 Inyokern, CA 93527 (760) 377-4478 (760) 408-9747 general and layout cell (760) 608-1299 technical and advertising cell www.vkss.com www.experimentalhelo.com "boB" wrote in message ... Has anyone seen, or read about, that Skycycle? http://www.thebutterflyllc.com/sscycle/gallery.htm http://javimoya.com/blog/youtube_en.php http://www.thebutterflyllc.com/sscycle/images/002.jpg http://www.thebutterflyllc.com/sscycle/images/012.jpg http://www.thebutterflyllc.com/sscycle/images/001.jpg http://www.thebutterflyllc.com/sscycle/images/010.jpg -- boB copter.six |
#7
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"Stuart & Kathryn Fields" wrote in message
.. . boB: BTW squared, In the process of doing the PRA magazine we met and spent some time with Comander Ken Wallis who is the UK gyro king. He did all of the flying for the James Bond movie that had the "Little Nellie" gyro. He doesn't share the statements that both horizontal stabilizers and center line thrust are a must. At least in his experience, and I might add mine (both my wife and I self taught in a Benson back in the late 60s and never dinged the ship and flew in a variety of conditions). This is not to say that some ships with an abundance of body work forward of the mast can't benefit from both things tho. I think that the two seat side-by-side gyros like the RAF and Sparrohawk would certainly fly different in gusty winds than the skimpy single seat Benson that I used to fly. -- Stuart Fields Experimental Helo magazine P. O. Box 1585 Inyokern, CA 93527 (760) 377-4478 (760) 408-9747 general and layout cell (760) 608-1299 technical and advertising cell Not trying to start any arguments here, there's been too many of them on this subject through the years, but.... I believe you when you say that h-stabs and centerline thrust are not necessarily a must. I know that many folks have flown gyros without these features for years without incident. I also know that in my first 5 years as a PRA member, it seemed like every time I turned around I was reading about "another" member who had killed themselves in a high thrust line gyro and "many" of these folks were not low time beginners. They were well established members of the PRA who's opinions and experiences were very much respected. Not all of these incidents were directly related to the high thrust line issue but some of them were, at least many folks seemed to think so. In the past few years, there have been a number of people who have converted a high thrust line gyro to centerline thrust and/or added a horizontal stabilizer and in each case, there have been nothing but "glowing" reports on the improvements in the handling of the aircraft, especially in turbulent air. I've read hours upon hours of posts and information and waded through heated arguments and respectful conversations on the subject and I firmly believe that, while an experienced pilot can safely handle a high thrust line gyro, I think a beginner or relatively low time pilot will be infinitely better off in a centerline machine w/h-stab. I'm not a gyro pilot so maybe my opinion on this isn't worth squat but I know what I've seen and I know what I've read and I firmly believe that a pusher style gyro should have a h-stab and the engine thrust line should be as close to centerline thrust as possible. JMMOC, FWIW! Respectfully, Steve R. |
#9
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"Stuart & Kathryn Fields" wrote in message
... Steve: I know what you are talking about. We got into a controversy when we produced the PRA magazine for publishing a letter from Cdr. Wallis outlining his opinions on the CLT and HS. I was kind of taken aback with all of the sudden inflammatory kinds of statements putting down the non CLT/HS ships as I had never encountered any problem flying my Benson and I flew it in the desert turbulence and winds strong enough to allow hovering takeoffs. My wife flew the ship and she had only soloed a Piper Colt. So we had no experience to support the damning criticisms of the Non CLT/HS ships. A conversation with Ken Brock trying to see if I had just lucked out and never experienced the close call in my Benson and he seemed to agree more with Cdr. Wallis than the current PRA position. I tended to use Ken as my expert on gyro things. BTW, as I recall, we had to set my Super Mac up even higher than the stock Benson because I was driving a larger diameter prop. I also had the outboard motor fuel tank that set below the seat. I'm sure that my thrust line was above the vertical c.g. with full fuel. The little rock guard on the Benson sure didn't qualify as a HS either. I guess I was either luckier than the others, or a good gyro pilot, or my ship was somehow more stable than the others. I know for sure there has been oodles of opinions and calculations floating about supporting the need for CLT and HS. Now that I'm flying adefinitely unstable aircraft (helo) my dog is not in the CLT/HS fight. -- Stuart Fields Experimental Helo magazine P. O. Box 1585 Inyokern, CA 93527 (760) 377-4478 (760) 408-9747 general and layout cell (760) 608-1299 technical and advertising cell www.vkss.com www.experimentalhelo.com I understand what you're saying about the inflammatory attitudes of some folks. As a very raw newbe in the PRA, some of them had me seriously wondering if I really wanted to be involved in this group? It was very difficult to figure out who to believe and who not too. I think it's better these days because there seems to be more of a consensus as to what's appropriate in a pusher design and what's not. Back then, it seemed like everyone had their own pet designs and very few folks ever agreed with each other! ;-) On the subject of the Bensen you learned to fly! One thing I remember reading about the original design that Mr. Bensen developed and flew was that it was relatively underpowered and/or used a smaller diameter prop than most of the modern (the original Air Command comes to mind) gyros do. As a result, the early generation Bensen's were much closer to centerline thrust than the larger, stretched out versions that have come afterwards. Is this something you'd agree with? Also, you mention putting a "super mac" on your Bensen and having to raise the engine to accomodate a larger prop which also, naturally enough, raised the engine's thrust line relative to the aircrafts CG. Do you remember how far you had to raise the engine? Makes me wonder if you were still under whatever magic number in thrust offset that kept you in a safe zone. I know that machines like Jim Vanek's SportCopter are not true centerline thrust designs but they seem to have (from what I've read anyway) very favorable flight characteristics. It makes me wonder if you simply didn't get far enough out of line for the bad characteristics to be a significant issue. Either way, I'm glad it worked out for you. I'd appreciate any comments you care to make on that. Thanks, Steve R. |
#10
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Steve: My Benson was definitely not under powered. I had a ball type
airspeed indicator that as I recall topped out at 85. I stuck the ball all the way up in the tube so far that I had to take a pipe cleaner and knock it loose. I was never passed by any other gyro. At the time we figured that I had done close to 100mph in straight and level flight. The Super Mac was very light and under ideal conditions delivered 95hp. The engine mount was raised some 2" to get the bigger prop installed. I can remember racing another Benson that had a Super Mac but a smaller prop and a streamlined body and I never saw them after I passed. The Benson manual recommended taxiing without the rotor installed to get used to the steering. The first time I did that I ground the wood front wheel brake almost in two and never got the throttle much off idle. The thing felt like a dragster without the rotor. After installing the rotor and getting it up to speed before taxiing very far, the thing became much more controllable. As I recall the thrust line on mine was just a couple of inches below my shoulders. Yeah if I was cruising along at say 50 indicated and firewalled the throttle without some aft cyclic, it would push my nose down a bit. I think that if I would have had a side-by-side fuselage up front to provide additional drag as the nose pitched forward, I might have had a different experience. I do remember that once in a while doing those Brock spirals, (zero forward airspeed and enough throttle to blow the tail around) the nose would sometimes get lower and lower giving me the feeling it was going to try to split S. I never let it get beyond about a 45 degree nose down before I stopped the spiral and flew out. Yep Vaneks bird looks pretty good and he can fly the thing. We have seen his loop and roll and it is darned impressive. I've also seen him get off the ground in a very short span. Take a look at the Magni in a front on view with Greg Greminger on board. I know he weighs at least 250 and imagine a passenger in the back. I can't believe that it is very close to a CLT. The Magni does have a HS though and the tandem seating doesn't give a real draggy front end. I rode in the Sparrow Hawk prototype which has all the CLT/HS and found it very stable but the control feel was monstrous. I had never flown anything including a T-38 that had such heavy controls. Even the Bell 47 with the hydraulics turned off didn't have such a heavy feel. Also the take-off roll was as long as a Cessna 150 on a hot day. -- Kathy Fields Experimental Helo magazine P. O. Box 1585 Inyokern, CA 93527 (760) 377-4478 (760) 408-9747 general and layout cell (760) 608-1299 technical and advertising cell www.vkss.com www.experimentalhelo.com "Steve R" wrote in message ... "Stuart & Kathryn Fields" wrote in message ... Steve: I know what you are talking about. We got into a controversy when we produced the PRA magazine for publishing a letter from Cdr. Wallis outlining his opinions on the CLT and HS. I was kind of taken aback with all of the sudden inflammatory kinds of statements putting down the non CLT/HS ships as I had never encountered any problem flying my Benson and I flew it in the desert turbulence and winds strong enough to allow hovering takeoffs. My wife flew the ship and she had only soloed a Piper Colt. So we had no experience to support the damning criticisms of the Non CLT/HS ships. A conversation with Ken Brock trying to see if I had just lucked out and never experienced the close call in my Benson and he seemed to agree more with Cdr. Wallis than the current PRA position. I tended to use Ken as my expert on gyro things. BTW, as I recall, we had to set my Super Mac up even higher than the stock Benson because I was driving a larger diameter prop. I also had the outboard motor fuel tank that set below the seat. I'm sure that my thrust line was above the vertical c.g. with full fuel. The little rock guard on the Benson sure didn't qualify as a HS either. I guess I was either luckier than the others, or a good gyro pilot, or my ship was somehow more stable than the others. I know for sure there has been oodles of opinions and calculations floating about supporting the need for CLT and HS. Now that I'm flying adefinitely unstable aircraft (helo) my dog is not in the CLT/HS fight. -- Stuart Fields Experimental Helo magazine P. O. Box 1585 Inyokern, CA 93527 (760) 377-4478 (760) 408-9747 general and layout cell (760) 608-1299 technical and advertising cell www.vkss.com www.experimentalhelo.com I understand what you're saying about the inflammatory attitudes of some folks. As a very raw newbe in the PRA, some of them had me seriously wondering if I really wanted to be involved in this group? It was very difficult to figure out who to believe and who not too. I think it's better these days because there seems to be more of a consensus as to what's appropriate in a pusher design and what's not. Back then, it seemed like everyone had their own pet designs and very few folks ever agreed with each other! ;-) On the subject of the Bensen you learned to fly! One thing I remember reading about the original design that Mr. Bensen developed and flew was that it was relatively underpowered and/or used a smaller diameter prop than most of the modern (the original Air Command comes to mind) gyros do. As a result, the early generation Bensen's were much closer to centerline thrust than the larger, stretched out versions that have come afterwards. Is this something you'd agree with? Also, you mention putting a "super mac" on your Bensen and having to raise the engine to accomodate a larger prop which also, naturally enough, raised the engine's thrust line relative to the aircrafts CG. Do you remember how far you had to raise the engine? Makes me wonder if you were still under whatever magic number in thrust offset that kept you in a safe zone. I know that machines like Jim Vanek's SportCopter are not true centerline thrust designs but they seem to have (from what I've read anyway) very favorable flight characteristics. It makes me wonder if you simply didn't get far enough out of line for the bad characteristics to be a significant issue. Either way, I'm glad it worked out for you. I'd appreciate any comments you care to make on that. Thanks, Steve R. |
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