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Girodreamer
Joined: Tue Mar 24, 2020 5:39 am Posts: 1056 Location: France
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Hi, in gyro the tests are not a big deal .. a bit of crow hops and after this a short pattern etc etc. when it comes to home built helicopter I imagine that the big test is the try to check the helicopter flies correctly in autorotation .. what is the method used to test an home made heli ? cheers G
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Wed Jan 18, 2023 4:05 am |
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Hillberg
Joined: Thu Nov 07, 2013 12:56 am Posts: 3073 Location: VERY LOW LOW LOW EARTH ORBIT
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Cruise flight 70 kts [20 kts over best clime settings] Lower collective to low stop roll off throttle slowly observe needles split rotors unpowered , rate of descent. Do a small quick stop observe rpm in rotor rise, Do a turn observe rpm rise. Roll on throttle observe joined needles with no over shoot [clutch doesn't cam over/slip] If all goes well you go on to H V plotting This is after rigging and track/balance , smoothing rotors and control conformation...and hovering.
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Wed Jan 18, 2023 4:35 pm |
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Girodreamer
Joined: Tue Mar 24, 2020 5:39 am Posts: 1056 Location: France
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an other world compared to gyroplane.
how can on be sure that his ne made helicopter is able to autorate good and safely ?
when one makes an helicopter and test it successfuly closed to the ground does it means that this machine is able to fly good on autorotation ?
in other words, how many people having build homemades dare to go into the pattern and then test it in autorotation ?
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Sat Jan 21, 2023 6:12 am |
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Hillberg
Joined: Thu Nov 07, 2013 12:56 am Posts: 3073 Location: VERY LOW LOW LOW EARTH ORBIT
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Some builders/designers can't fly couldn't fly or never flown The good ones are very knowledgeable and build a nice machine but are not pilots so they'd get a pilot to do the tests. Some think they can fly what they built and wreck their golden idol. Some pilot just wiggle the sticks but lack the mechanical side and can't figure out what the problem is or how to make things better.
Control harmony - stick forces - breakaway forces - a feed back loop - A feel for the machine that is flown for the first time.
And that is beyond the requirements for an experimental certificate from the CAA & FAA.
Mostly if it looks good you have a chance of it flying right...
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Sat Jan 21, 2023 5:35 pm |
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Girodreamer
Joined: Tue Mar 24, 2020 5:39 am Posts: 1056 Location: France
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This is what I suspected in fact .... I have nearly never seen an home built internet "story" ending in a real pattern ..
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Sun Jan 22, 2023 3:44 pm |
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Hillberg
Joined: Thu Nov 07, 2013 12:56 am Posts: 3073 Location: VERY LOW LOW LOW EARTH ORBIT
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Girodreamer wrote: This is what I suspected in fact .... I have nearly never seen an home built internet "story" ending in a real pattern .. When I tested the Rotormouse it was more of a non event, With all the testing on the ground to the 1st flight we had done so much planning and running the cards - We knew how'd it was working out. It flew faster and better then planed. What wasn't planed was BJ Schramm and Dennis Fetters hit on the market. BJ with a turbine helicycle and Dennis with the Mini 500 killed the market. Literally killed it along with a bunch of pilots https://www.bing.com/videos/search?q=ro ... &FORM=VIRE
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Sun Jan 22, 2023 4:29 pm |
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Girodreamer
Joined: Tue Mar 24, 2020 5:39 am Posts: 1056 Location: France
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What a pity the rotor mouse could not find it's place on the market ...
About the tests it is clear that you can't compare your tests with the tests a pure amateur would make after making it's first helicopter in his garage ..
I managed to test my first gyro but designing a gyro, building it and testing it is just a piece of cake compared with designing , building and testing a helicopter !
how many helicycle and mini 500 lethal crashes have occurred in total ?
did fetters have legal issues ?
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Mon Jan 23, 2023 10:28 am |
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Hillberg
Joined: Thu Nov 07, 2013 12:56 am Posts: 3073 Location: VERY LOW LOW LOW EARTH ORBIT
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Haven't a clue sold and flying are two different animals Helicycles 160 odd kits sold -60 to 80 flying? Mini 500 about 500 kits sold 200 odd flying? Jet exec conversion kits sold 110 about 60 flying? The only ones to hold their value are Jet Execs - Rotorworks supports the Rotorway Exec. Revolution is defunked = No support 10% fatality rate [No good] Helicycles have supply issues with engines [Surplus T 62 T 32 engines are harder to find these days]
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Mon Jan 23, 2023 3:21 pm |
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Girodreamer
Joined: Tue Mar 24, 2020 5:39 am Posts: 1056 Location: France
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Those numbers are crazy big ... 10 % fatalities I just can't imagine this ... were those accidents caused by mechanical reasons ? In Montelimar (my aerodrome base) we had a fatal accident on a LH212 Delta Italian heli .(two people killed) one of the Two anti-torque rotor Blades broke ... and soon after the second hit the tail and also broke see the BEA (investigation bureau) it is in French but you have the pictures : https://bea.aero/fileadmin/user_upload/83AQG.pdffor me it is crazy to use aluminium to build this blade fixing ...it even seem to be an aluminium casting as a mater of fact the metal has a grainy looking ... making me think it is a casting .. they are pointing out the fatigue of the material all of this is a lake of engineering
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Tue Jan 24, 2023 6:41 am |
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Hillberg
Joined: Thu Nov 07, 2013 12:56 am Posts: 3073 Location: VERY LOW LOW LOW EARTH ORBIT
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Not a forging no grain structure
Castings have irregular surfaces
The second picture has a dark area on the lower failed piece that's an old crack working the shiny bit is a new fracture 1/4 of the area failed first and a catastrophic end with the last 3/4 of cross section.
Couldn't read the report but it was obvious the bearing staking was a stress riser and not enough meat on the part The company redesigned the piece , That should of been beefier in the first place
Could of been a 'cast plate' got machined and not a rolled billet [cast plate makes fine fixtures and jigs. bad for stressed parts]
A well trained pilot who got complacent and surprised after a T/R loss of thrust event.
Had a buddy I worked for lose a tail rotor on a S 58 T, They parked it on a school field - The gear box came loose and even if they lost it they removed the torque during the auto so no loss if heading
Had an old guy getting time so he could play in his Jet Exec and at a hover he stalled the tail rotor , after the first spin around I looked at him. He had a puzzled look and the left peddle was on the stop. I took the controls and just rolled off the throttle - the Brantley has nice landing gear. The tail rotor split a keyway in its gearbox...
Some people become passengers after little events and stop flying... The wreck shows this.
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Tue Jan 24, 2023 3:00 pm |
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Henry Bowman
Joined: Wed Nov 06, 2013 4:03 pm Posts: 2408
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'Some people become passengers after little events and stop flying... "
Truer words never typed... I try to not let myself ever become a passenger.
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Tue Jan 24, 2023 5:39 pm |
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Girodreamer
Joined: Tue Mar 24, 2020 5:39 am Posts: 1056 Location: France
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Hillberg wrote: Not a forging no grain structure Hillberg wrote: G : the report says one of the broken surface is granuar and the other is soft, as a matter of fact they don't say the part has been casted .
Hillberg wrote: The second picture has a dark area on the lower failed piece that's an old crack working the shiny bit is a new fracture 1/4 of the area failed first and a catastrophic end with the last 3/4 of cross section.
this is what they say, the had done it's work for a certain time before Hillberg wrote: Couldn't read the report but it was obvious the bearing staking was a stress riser and not enough meat on the part The company redesigned the piece , That should of been beefier in the first place
Could of been a 'cast plate' got machined and not a rolled billet [cast plate makes fine fixtures and jigs. bad for stressed parts]
A well trained pilot who got complacent and surprised after a T/R loss of thrust event.
Had a buddy I worked for lose a tail rotor on a S 58 T, They parked it on a school field - The gear box came loose and even if they lost it they removed the torque during the auto so no loss if heading
Had an old guy getting time so he could play in his Jet Exec and at a hover he stalled the tail rotor , after the first spin around I looked at him. He had a puzzled look and the left peddle was on the stop. I took the controls and just rolled off the throttle - the Brantley has nice landing gear. The tail rotor split a keyway in its gearbox...
Some people become passengers after little events and stop flying... The wreck shows this.
they were on in mid downwind branch with possible places to land .. there was an instructor and a trainee in the heli ..
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Wed Jan 25, 2023 2:47 am |
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Hillberg
Joined: Thu Nov 07, 2013 12:56 am Posts: 3073 Location: VERY LOW LOW LOW EARTH ORBIT
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Looks like they just quit flying and lost rotor rpm - Splat. The area they landed in was enough to walk away from even if the helicopter rolled over.
Floyd took me up in an Enstrom one day to show me something wonderful, With his feet flat on the floor he pulled up into a hover and of course the helicopter started to spin after 2 turns he added cyclic for his desired heading. After we hit translational it flew sideways the whole pattern the boom weathervanning as we went on final it was straight ahead until the powered flare and a single spin on set down - All the flight his feet never left the floor... Amazing
Never quit flying
Cast plate looks exactly like billet, Only microscopic examination and material testing can tell the difference. Sad to lose people for any small over sight
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Wed Jan 25, 2023 2:33 pm |
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Girodreamer
Joined: Tue Mar 24, 2020 5:39 am Posts: 1056 Location: France
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I have the feeling that the difference btw gyros and helicopters is the same that the difference btw opened circuit scuba appartus and rebreathers ...
many of the people who died diving on a rebreather thought they could dive rebreathers because they could dive an open scuba system.. which is all but true ..
we are used the say thay one really must not turn his back to a rebreather ... (I mean low down the guard) ..otherwise the rebreather will stab him in the back !
a rebreather can kill you without warning unless you constantly train to use it in a degraded mode of operation ... and work out the safety procedures often .. partial pressure oxygen cell do fail on a regular basis
this is a system which offers you up to 10 hours of breathing time at any depht ... but if it fails, you could end up with a one minute time left to breathe sucking your 3 liter depth mix .. (we are talking of diving in the 100/130 meter zone)
it you are not trained to pass in degraded modeof operation immediately or to start an immédiat ascent on a small open circuit tank you will never make it to the surface with kind of 2 hours of deco stops ...l
you need to find the trouble cause in seconds and make your safety decisions in seconds also .. and you are alone because no one can share breathing gas with you at 120 m !
on opened circuit diving, at 120 m we dive with 2 huge independant depth mix gas tanks (heliox), in case of a leak you just have to switch from a tank to the other and tha't is you have 15 minutes (an eternity) to make your decision ,, start your ascent etc... on a rebreather you pass from 10 hours duration to one or 2 minutes ( a rebreather only have a 3 liter depth mix tank...) before drying your depth mix .. if you try to breathe your stage tank nitrox at 120 you will loss conciousness immediately ( to much oxygen pressure in the mix)..
so in case of a problem .. you only have seconds ..
it is a bit like reacting to loosing an anti torque in an heli I imagine !
I imagine that training is the key point ... I would spend half of my diving time trying my safety procedures in real conditions ...many of my self taught friends died .. I had been trained by the american IANTD agencies ... which has a saying written everywhere : Training is paid certificationis earned ...
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Wed Jan 25, 2023 6:22 pm |
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