Flying Rudders....

Discussion in 'Aircraft Design / Aerodynamics / New Technology' started by Southron, Jul 11, 2012.

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  1. Jul 11, 2012 #1

    Southron

    Southron

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    I have got a set of plans for a Zenith CH 750 STOL. I note that the CH 750 utilizes an "All Flying" Rudder. I am just wondering about what would be involved substituting a Mooney type vertical stabilizer and rudder in place of the Zenith's "All Flying" Rudder. Would it be possible?

    The big advantage I see is I think a Mooney type vertical stabilizer and rudder could withstand a bird strike by say a duck or goose better than an "All Flying Rudder".

    Your insights, advice and comments would be Welcome.

    THANKS!
     
  2. Jul 11, 2012 #2

    TFF

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    I dont think it would change strength much as the aluminum thicknesses would not be much different once re engineered. An actual Mooney tail would be stronger as it is much heaver material. I will also say a goose will take off both fins if hit square. I have seen geese knock engine mounts off turboprop regional liners and cave in panels that you cant duplicate with a sledge hammer. Much faster planes for sure, but you hit much more than a tweety bird and it's doing damage.
     
  3. Jul 11, 2012 #3

    Detego

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    Of course you could ask the designer about your Conventional Rudder. To answer your question - YES - it is possible.

    Note: back in WWI the Fokker-type utilized the "full flying" rudder.

    [​IMG]
     

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    Last edited: Jul 15, 2012
  4. Jul 11, 2012 #4

    Aircar

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    Ducks would have a hard time taking out that Fokker rudder ! (Duck's last thought .."What the Fokker !?...

    All flying fins have some advantages --see the SR 71 and some gliders but especially all flying V tails --for the Fokkers it allowed flat skidding manouvers to better aim machine guns ( also a much better way to deal with miscreant ducks :gig: )
     
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  5. Jul 11, 2012 #5

    Head in the clouds

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    As for ducks... I was in transit Fitzroy Crossing to Broome (Kimberley, NW Australia for non-Aussies) right seat in someone else's C210, at A8500 and was chatting with rear seat pax when the pilot suddenly blurted something and ducked below the panel. Then came a massive banging and jolting of the plane, I never had time to duck(!), the rear seat pax started to yell and scream and when I looked forward the windshield was totally redded out.

    We'd hit a flock of ducks. The starboard strut was badly dented in two places (u/s) and l/e of the same wing had several very large crumples and three football sized holes, main spar dented etc. No HF radio, antenna cut. The only reason the windshield held was the ducks that hit it were minced by the airscrew. Not recommended and didn't know ducks had such a good service ceiling.
     
  6. Jul 11, 2012 #6

    Aircar

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    Duck attack (Kamikaze) is a frequently overlooked danger --lucky you had a zero displacement engine in the C 210 or who knows what could have resulted ! :gig: No joke though --been attacked by an eagle but never had a mid air with a bird , Ben Buckley (20 000 hr crop duster and all round wild man of the air said he had never hit a bird in many years of low level work --presumably they can hear you coming and take evasive action (which raises concerns about ultra quiet and electric aircraft --silent gliders seem to get attacked as competitor 'birds' but haven't heard of actual collisions eg while thermalling .* STOP PRESS - just recalled one photo of a pelican sticking out of the wing of a Bocian that happenned in the sixties at Mildura (Tony Tabart pilot ) --"Bocian" is Polish for Stork so it might have been a grudge thing ...

    The medivac helicopter had had a mid air bird strike en route to landing next to my humble abode a couple of months ago but hit right on the cable cutter on the front screen centre .
    I recall that they said that geese flew OVER Mt Everest on the recent show about Bear Gryll flying a paramotor above it also and some other source way back --certainly thermalled with eagles well over 10 000ft

    When we darken the skies with flying cars 'surfairs' etc I wonder if the birdstrike risk will become a significant factor -- you might have struck those ducks from behind I suppose so they would not see you coming at all .
    I wonder if you heard the jokes about the Sth African (Atlas aircraft ?) "Kudus" having bird strikes --on the TRAILING edges ! ( they were supposedly very slow at least by air force standards --your African boyhood might have been a bit too early though -? There was one in Victoria and it had a 'soft' rubber mounted tailplane which I hadn't encountered before as one peculiarity.
     
  7. Jul 12, 2012 #7

    TFF

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    If you hit a duck with a LongEZ does that 0 out the force?
    Many airliners have ballistic shields, about 4 in thick, if there is not a bulkhead in front of the first cockpit bulkhead, to keep the birds out.
     
  8. Jul 12, 2012 #8

    Georden

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    I've had a few close calls with birds, scared the crap out of a seagull in a 172. Been in a helicopter that had a small bird go through it's main rotor, would never have known if I didn't see it. Makes me wonder how many I've hit and not noticed, always assumed the odd blood splatter on the blades was from bugs.
     
  9. Jul 12, 2012 #9

    Aircar

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    Birds getting sucked into jet engines is understandable and not seeing helicopter rotors also but wind turbines doing only 19RPM are also claimimg their fair share of birds (the rare 'orange bellied parrot' that commutes across Bass strait here has been cited as one reason to prevent wind turbines --or at least shutting them down during the migrating season )

    Raptors are particularly vulnerable apparently --they don't have to dodge anything else in nature so might not be aware of threat from anything faster (with tips of turbines at 2/3 of sonic speed on some )

    Still finding it hard to see why a fin on an aircraft should be especially vulnerable or why being all flying should make a difference (?) - I HAVE had the fin on an aircraft ripped off in flight and it was virtually an all flying rudder (ES52 Kookaburra if you want to google it ) --a very small fixed fin with the rest a horn balanced all moving surface ; in that case a stray winch parachute was picked up and tangled in the release and ended up over the tailplane with the cable still attached - opened up and ripped the fin off with only the rudder cables retaining it for a double "Tailchute" landing.

    Also had a tail strike in my old Sagitta (Dutch 60s sailplane )when the sliding bubble canopy came loose on winch launch and hit the tailplane before disintegrating --a case for independent control of each side of the horizontal tail in case of impact could be made .
     
  10. Jul 12, 2012 #10

    Detego

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    A study years ago stated that - BIRDS play chicken with cars on purpose - the conclusions was they like the RUSH!

    unrelated: http://www.concordesst.com/latestnews_02_1.html

    [​IMG]
     

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  11. Jul 12, 2012 #11

    ultralajt

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    Check Zenith copy "[FONT=Trebuchet MS, Arial, Helvetica]Savannah"
    [/FONT]Savannah is equipped with classical vertical tail.. fin and rudder.
     
  12. Jul 12, 2012 #12

    SVSUSteve

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    I was a student pilot/passenger in a plane that hit two geese. Piper Comanche wing tip/leading edge versus Canada goose #1. Goose #2 hit the vertical stab. Both areas looked like we had hit a tree. Impacting a goose at cruise speed is an experience I don't wish to repeat any time soon. It makes one hell of a bang and certainly gets your attention.

    We have two common "orange cheeked parrots" (also known as cockatiels) and have to keep the ceiling fan turned off because they seem to intentionally fly at it. What's really funny is if they are out, have landed up there and no one noticed before turning the fan on. It's probably the closest thing a cockatiel can get to a carrier style catapult launch. God those birds are ****ing stupid.
     
  13. Jul 12, 2012 #13

    litespeed

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    I have had a bird strike at 80 knots with a Galah- med/large native parrot, pink and grey.

    It was one of those days when you live by a tiny margin. Hit me smack dead in the helmet visor on a full face helmet. Yes I was on a motorbike, possibly the only worse place than a plane for a strike to the body. It was literally like been hit in the head with a sledgehammer, I was very disorientated and almost passed out, the visor was smeared in pink feather oil and blood.:shock: It was sheer luck and masses of riding miles that allowed me to keep upright and slow down to stop then collapse.:depressed

    If I had a open face with visor or a cheaper helmet (top line race spec Arai) I would have been dead probably before the bike even crashed. I had previously seen a fellow rider hit a Kookaburra face on and he never had a chance-the beak pieced his face and nailed his brain.

    Point been a bird can kill at any height and in any relatively exposed vehicle.

    Physics is a deadly bugger sometimes, even tweetie bird can kill.
     
  14. Jul 12, 2012 #14

    litespeed

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    As far a max altitude, many migratory birds fly at very high altitudes and use the jet streams at various flight levels aircraft frequent.

    Makes great sense for them, a lot faster and far lower energy use, some birds do not refuel as such but just do huge legs and land starved at the destination. Some get unlucky and die on the wing.

    Luckily the Southern Albatross- worlds largest flying bird is rarely seen far above the cold southern seas. That bugger could take out almost anything flying. Wing span like a Cri Cri. Make a goose look like a bug splatter.

    Just checked- Southern Wandering Albatross
    wing span normally 12 feet but up to 13.8 feet.
    weight up to 28lb and max recorded for young with first (still fat heavy) at 35 lb.
    Range more than 500 miles a day.
    Glide ratio 22:1 uses wave soaring and ridge soaring, thermals for flight, heart beat in cruise is almost same as rest. Only take off and landing are energetic.

    It is natures perfect sailplane, just don't hit one.

    Those weights and physics means the coroner will get to do the calcs.

    Steering clear of birds
    Phil
     
    Last edited: Jul 12, 2012
  15. Jul 12, 2012 #15

    Starman

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    [video=youtube_share;buuxFP--Ezo]http://youtu.be/buuxFP--Ezo[/video]

    Sometimes Albatrosses fly across the Atlantic and back, to Brazil, to get squid for their babies.
     
  16. Jul 13, 2012 #16

    ultralajt

    ultralajt

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    Are we still talking about flying rudders or it is all about duck hunting season? :roll:
     
  17. Jul 13, 2012 #17

    Detego

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    [​IMG]


    rudder.jpg
     

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  18. Jul 13, 2012 #18
    Hi, you are thinking new technologically. So try it once lets see what happens. I always support innovations. So I am here to support you on this forum. :):)
     
  19. Jul 13, 2012 #19

    Dan Thomas

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    That isn't too accurate. The relative wind is seldom at that angle except, perhaps, in a tight spin, and the angle of rudder travel has limits to prevent the stall as shown in any expected flight maneuver. The picture of the all-flying rudder shows no stall turbulence, but if it is moved to stop a spin it might suffer the same thing since its AoA will increase to stall angle.

    My Jodel has an all-flying rudder. Enormously powerful, but it does lead to some hunting in yaw in cruise if the air is a bit rough. It wants to streamline itself with the relative wind and when turbulence alters the direction of wind, the airplane will yaw and the rudder will let that happen by aligning itself with the wind instead of fighting it. Some Jodels have a centering cam on the rudder system to reduce that instability.

    As far as birdstrikes: Any bird that could knock off the flying rudder could also knock off the stabilizer or punch out the pilot's eyeballs. One has to watch for stuff like birds and other airplanes. I once encountered a bald eagle and had to dodge him. He was coming at me. More often it's hawks, who tend to be territorial and will try to intimidate the airplane.

    Dan
     
  20. Jul 13, 2012 #20

    TFF

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    birs.jpg
    This is one I had to fix. Hawk at 90 mph. If it had been a foot higher, there might have not been a happy ending.
     

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