French Gyro's

[mad max]

I have a student who is in France at present checking out the JRO Cabriolet made by DTA 912 or 914 engine. Allso the ELA10 Eclips. He is asking if these craft are acceptable in Aust. He"s been on a TIF in my Rosco Clone but seemed a bit nervous sitting on a barbaque stool with nothing under his legs and strapped to a pole with an 86 car engine strapped to the other side.

[mick.kelaher]

looked them up they are a nice gyro

[MadMuz]

Wow, they do look nice.... trouble is the brochure says an MTOW of 450KG (510KG) not sure which? But it doesn"t mention the empty weight? So, if you add a pilot at 110kg, a passenger at 80kg, luggage.... say 10kg and 70L of fuel.... that is say 50kg....... so that is 250kg of weight for it to carry, I hope the machine with rotors on only weighs 200KG?

[MadMuz]

Wow, I hope your student is rich?? They are 87,000 Euros without optional doors, instruments, engine thermostat, etc, etc so a 914 without metallic paint and without any rear instruments

[mad max]

Plenty of money in the NT teaching indiginous people computer skills. He wants to fly around instead of drive. According to the NT news indiginous people get 3 times the hand outs of others in the NT. The recent doc. on SBS gave a false impression. Sounds like the JRO Tandem craft is fibreglass and not carbon fibre. Sounds like the ELA 10 may be a better deal. I still don"t believe these high tech machines should be taken to full throttle before nose wheel lift.

[gyroo]

Howdy Max, Muz and gang,RE the Euro "450kg" BULLCRAPThat 450kg has to be put into the brochures of most Euro gyros "cos most of the individual European states still classify gyros under the fast-becoming-obsolescent "microlight" rules, first implemented under the-then JAR code (now repealed). Until the new EASA scheme is implemented throughout the EU, all the EU states are "going it alone" with all sorts of different rules.The same 450kg weight is apparently initially being carried over into the upcoming EASA regulatory scheme.Australia is in fact leading the pack with its 600kg gross weight. Some European jurisdictions impose 580kg, or 544kg, but mostly 450kg.Of course, the brochure figures are absolute bullcrap and almost all 2 seat Eurotubs would be easily grossing 530 to 630kg.Cheers,Mark ReganMelbourne

[MadMuz]

Thanks Mark, so that must be why it has 450kg then in brackets 510kg?

[tonydenton]

the bottom photo of the French machine looks extremely light. the size of the keel out the back to hold

[MadMuz]

The front seat limit is 110kg Tony, so, yey it prolly wood

[tonydenton]

I hadn"t read the specs muz. but even if I was 109 kg I wouldn"t . is the specs 110kg in the front seat ,on smooth air strip and good landing or will it handle a " grass strip and a bit of a drop ???? "

[mad max]

The reason I guess that the young chap is keen on a french Gyro is because he is a Frenchman and goes back regulary. He is asking what is the procedure for certification if he turned up in one in Aust. Apparently they are certified in Canada.

[gyroo]

Howdy again,The actual upper limit of any gyro"s actual load carrying ability is when the climb rate drops to unsafe levels - ie: less than 250fpm. Runway length is of course another factor.Some "back of the envelope" calculations shows from the standard text book Gessow & Myers shows that a 25 foot rotor can conceivably carry an Imperial ton (2240 pounds) at 608 rpm. I then went over to Jukka Tervamaki"s "GyroCalcWin" program which is a very useful program based on the standard textbook equations, but which does all the work for you. Interestingly, the ultimate rotor rpm at 620 correlates very closely to the manual calculation, but what is of great interest is that no matter how many horsepower you plug into the engine power box, the GyroCalcWin program says that there will be no rate of climb at any horsepower. I strongly suspect that this is showing up a glitch in the program, rather than it being impossible for a 25 foot rotor to lift a an imperial ton.Nevertheless, rather than waste hours out of my Sunday doing tortuous manual calculations, I reckon the Tervamaki program is good enough to get a "ballpark" idea. So, I plugged in a realistic horsepower of 400 and increased the rotor diameter to 27 feet. Weight was plugged in at 2240 pounds. The result on the Tervamaki program was that it could fly at between 90 and 110kmh and would get 40 fpm climb rate at 100kmh.Increasing the rotor diameter to 30 feet the program says that with 400hp lifting a ton (2240 pounds), a climb rate of 180 fpm is achievable at 100 kmh.Increasing the rotor diameter to 32 feet at 400hp lifting 2240 pounds gives you the minimum legal climb rate of 250 fpm but ONLY at 95kmh, and the program says that straight and level flight would only be possible between 75 and 125 kmh. Also of note is that the rotor rpm is 420 but that the coning angle is 4 degrees. All good fun.The only other interesting observation that the Tervamaki program shows is that for a given rotor diameter, the coning angle does not change as the rotor rpm goes up as weight increases. This correlates with "book theory", which shows that for a given rotor diameter, if the autorotative process speeds up the rpm, the coning angle will remain the same. This is a significant point to note, because it means that the hub bar won"t be being bent up and down much, although obviously the centrifugal loads will increase exponentially as rpm goes up. There would have to be a point where the hub bar would fracture from those forces after a given number of hours. I"m not gonna bother doing those calculations!Cheers,Mark R

[gyroo]

Re FranceThe FAI website says that France has 700 registered gyros, all registered as "Microlights" limited to a gross weight of 450kg. French gyro pilots apparently carry a "Microlight licence" endorsed with "category 4" (autogyro). Curiously, France also imposes a power limitation of 90 Kilowatt for 2 seat gyros (which is 120 hp).France is apparently the country with the most gyros in Europe - Germany is stated as 388 machines.Mark R

[mad max]

Sorry Mark, too much theory for me. I"m intellectually lazy. Just fly by the seat of my pants. You know when they"re good or not when you ride them. Just like a woman. (Mad muz started the dirty talk)

[birdy]

Mark, im thinkn that the limiting factors on max rotor load are to do with air compressability and tip speed.You get to a point where more HP only makes more noise.And yes, it dont matter if theres 6 or 600 kg hangn off them, the cone angle will be the same at a steady 1 G .