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It was brought to my attention that i should post this for people that dont visit the Yanky Forum there is currently a interesting dicussion regarding CLT and a Recent Accident, Also looks like there is talk about wanting to change rules regarding High Thrustline Gyroplanes in Australia.Discussion here: http://www.rotaryforum.com/forum/showthread.php?t=25794Regards Trent.
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Trent,Thanks for putting this thread up, It only makes me wonder why there is disscussion on the topic on the American forum and not here?Mark.
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Mark, The initial responses to this thread was to correct some erroneous comments about the recent accident in SA.I implore all ASRA members to read the posts on the US forum plus the many others over the years that have discussed thrustline/cog placement and center of drag etc.Serious discussion is now taking place at Board level concerning changes to rules with regard to gyroplane construction.
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I`m new to the sport (80 hrs six months) and i was wondering how you class these High thrust line gyros? how does the weight of the rotor blades affect this? the weight of my blades are 44Kg plus rotor head etc and its high above the thrust line and the total weight of my empty gyro is 180kg
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A thread was started here asking about the accident, condolences were said and it was left at that, as it should be on this site.This is the ASRA site, it was an ASRA member lost and there is an ASRA investigation underway. Findings will be released when they are finalised and we know that. There is nothing wrong with the discussion on the American website and I think the only reason it was not conducted the same here was out of respect.And no doubt a discussion thread will start up here under the appropriate heading.
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Murray said"Serious discussion is now taking place at Board level concerning changes to rules with regard to gyroplane construction."On the US forum it was said"Perhaps the fact that a current owner of a highly unstable gyro will have an issue reselling his machine will wake a few people up?"Perhaps a work around is that the results of the hang test be part of the papers exchanged when a gyro is sold. Along with a statement, that it is generally believed that a thrust line that deviates more than "x" inches is not stable.When I sell a house, a section 32 is required. Maybe when I buy a gyro I must read a list of points to look for when buying said gyro. And I can sign my acceptance of deviations.Graham
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mitch , you said your gyro can"t PPO. because of your design and position of your hs. is that statement true ? couldn"t any gyro PPO in a worse case cenario ?
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Murray, the yank forum is a big read and the points of veiw are pretty repeditive. I remember reading one comment that said something like" my machine is HLT and I know my limitations, I do not fly past them"I would say that I know my limitations, but sometimes the air that I am flying in wants to exceed them. They are those "Holy CR4P" moments when a well designed gyro gives the pilot the chance to fly another day. As someone who flys over 100 hours a year, I now have the experience to know that things can happen in a milli second and as I get older, My reaction time is slowing. (although hours in the seat help me to anticipate what could happen)In my ten years or so of being involved with Gyrocopters the forum has been populated by four types of people, those that want to fly gyros, those that want to build them, those that want to build and fly and those that do fly.Given the amount of people who want to build gyros from scratch, that never intend to fly them and those that intend to fly them, but never get round to it, there must be lots of untried designs sitting around in sheds all over the country just waiting for an eager purchaser who"s aeronautical experience is limited to jumping a bicycle off a brick and a plank, to take home, love and think is the best aircraft since Apollo 11.I have a few at home in my shed (the boulevard of broken bank accounts)Good design is the buffer between incident and accidentMark.
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mitch , you said your gyro can"t PPO. because of your design and position of your hs. is that statement true ? couldn"t any gyro PPO in a worse case cenario ? My gyro"s HS is in-line with the thrust line, no load and is approx .8 sqm and 1.6 m behind the vertical C of G. Thrust is slighly below the vertical C of G.My gyro will not PPO. G"Day Tony,The Butterfly will not PPO!
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mitch , you said your gyro can"t PPO. because of your design and position of your hs. is that statement true ? couldn"t any gyro PPO in a worse case cenario ? Tony,I would reckon that in theory you may be right, but Im sure there is someone out there to shoot me down!I live on the edge of the Great Dividing Range and am no stranger to fairly exciting Westerly wind rotors and cracking thermals on hot days, I think that it is for this reason, that I never seem to fly without having my left hand firmly attached to the throttle. There is no substitute for actually flying the machine, but I think that good design makes it easier.My first Gyro was a "low profile" type (and was the norm 20 years ago) when you pushed the power on the nose dropped, take it off and the nose came up. It made for some good throttle/stick co-ordination training if you wanted to get on the ground in one piece!The second was a "High profile" and flew more like what we all fly, but was "twitchy in crappy weather" The third, I built and made it what I thought was CLT, as the nose didnt raise or drop with power, it just climbed,and I still think that it was the best single seater that I ever flew, if only a little lacking in power.I now fly a Roscoe Tandam and It is pretty damned good to fly, I have seen speeds in excess of 80 knots on the ASI, but I pick my days!On those lumpy, thermally days, I am content to poke along at 50 knots and am happy to Mush through some of the better updraghts with the power off to 2000 revs or less.Would my machine PPO?, I dont know, but I wouldnt say it couldnt, and I dont want to find out!.Mark.
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Hi All,With What my mind thinks i believe that Mitch is right in his statement above His Gyroplane may not PPO (Power Push Over) but it may still bunt over in the right situation. (Or wrong situation however you look at it.)He is also right that: "PPO is not the same thing as a drag over due to a very low centre of drag. The Butterfly does not have a very low centre of drag."This is something that i believe that some have forgotten or never understood (As I admit I didn"t) and by dumb luck they have had gotten it right when they built their machines.I personally think that you may be able to have a HTL (High Thrustline) gyro with a low COP (Centre of Pressure/Drag) that evens out the forces at a certain speed but when at a slower speed your in trouble with the risk of PPO, or at a higher speed your also in trouble for example going 80 knots and cutting the power and then having extreme centre of pressure drag pulling you under and maybe not having enough back still to recover. This comes back to Understanding and training for such a gyroplane and instilling the second nature reaction for said gyroplane. ( Im sure some will say that a gyroplane shouldnt have to be like this, there are many an aircraft out there that have stall speeds and VNE"s people have came to accept that and fly quite fine within it range. Perhaps my Attitude is wrong and unhelpful?) If the conditions are bad or things are getting hard to keep up with then SLOW down, Im sure people that have flown other aircraft types will agree that when $%^& hits the fan you slow down. (Unless your stalled of course
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Trent,the last line in your post is spot on!Mark.
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Trent, with all due respect, I do not believe it was dumb luck which led Larry Neal to re-configur the old AirCommand low riders to the current day, new generation CLT type configuration. There was always a requirement to get the C Of D coaxial or nearly so with the thrust line.Even Bensen knew the benefits of CLT and reducing the various turning moments around the C Of G.Later, There were several people in
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Mark,I find it curious that whilst you support Trents comment, " i also believe that there should be more empathizes and testing on gyroplane theory at student level."that after 10 years and several machines, especially now that you have a two place machine, that YOU DO NOT KNOW IF IT COULD PPO.If your gyro has a considerable offset, (HTL) which can be measured, and it is not balanced by a suitably adequate HS with negative incidence, then yes it could PPO.Of course you know a tandem is far more pitch stable (even a HTL) than short coupled side by side or single seat HTL gyroplanes.There are people who can calculate the moments and advise you on this.Here in lies the problem as I see it.How can we expect Newbies to understand the dangers if the experienced blokes dont know????
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It looks like discussion is going to happen Peg, so i"m putting my 2 bob"s worth in.I fly a Rosco /2.2 Suby 76 inch prop with a pod, it would I believe be a HTL gyro.I used to think CLT was rubbish but now with circumstances as they are now, cannot defend HTL any longer, particularly for the relatively inexperienced pilot and really, why, when we do have the information, why not make a HTL a whole
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