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Arrow-copter. This is my dream-gyro

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  • #16
    I do not know details of this design (nor I can read German). I just noticed on the two photos earlier in the thread (the side one mostly) that air intakes go more up towards the prop (if you can say so) which would mean that in normal flight the nose should be upper to make them level. ... If it is true - then it is not a dramatically HTL.

    Xeneon is also slightly upper TL (it as discussed on the forum) the cabin aerodynamics adds up to total stability picture.

    It might be a similar case.

    A regular gyro would have TL level and the prop thrust adds a bit to the total lift when the nose goes up at the take off, but nobody said It has to be like this.

    I just wonder if I'm right.

    Leonid
    Last edited by Leonid; 05-30-2008, 01:09 PM.

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    • #17
      I found this OLD thread and wonder what these opinions are now of one of the nicest if not the finest examples of the newer gyro's.

      As is now apparent to me form can follow function.

      And really what's wrong with that if it's safe and TRAINING is in place!?;)

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      • #18
        I have a thing about T tails. I built a wind tunnel to test all of the different tail designs for a pusher gyro back in 2008 thinking that a V tail would be great. I was right, although Ernie's cruciform tail is the best, the V tail is a close second, and the original Bensen design with the HS ahead of the VS is unbelievably stable! And I discovered the T tail stinks - it is by far the worst design of all, which tells me that anyone whoever designed a gyro with one did absolutely zero testing of models in a wind tunnel, quite obviously. And if they didn't bother to test aerodynamics of their design, what the hell are they doing designing and selling anything that flies and that my life depends on? Just goes to show you can sell anything so long as you find a sucker to buy it and call it experimental. Major faux pas in my book and a seriously good reason to pass this gyro up. You see, as the prop wash twists and hits the T, this design catches it in one quadrant only and causes major adverse yaw which when coupled with a crosswind can create completely unnecessary control issues. Get a real tail. WIth the Bensen, the HS is ahead of the VS and the wind slips right by without getting trapped and causing problems. Imagine that.
        GT Mills
        Peachstate Rotorcraft Club

        Mohawk Aero Corporation
        PO Box 30133
        Savannah, GA 31410
        www.MohawkAeroCraft.com info@MohawkAeroCraft.com

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        • #19
          I'm in agreement with you Mike about the vast difference between the large forward side surface area with the fuselage and the diminutive surface area the the vertical stabilizer.

          Greg, I do certainly like the size and amount of surface area you have on your tandem Air Command.

          Jerry, I have a story about the toy Arrowcopter. In April of 1968 I was playing with my recently acquired Arrowcopter toy in front of my house when it was caught in a tree. I went into my house to get my football to dislodge the toy when I found my mother sobbing in front of the TV. The announcement just came through that Dr. Martin Luther King had been shot.

          Wayne

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          • #20
            The Arrowcopter has been around for that long ??? I don't think so !
            Happy Flying, Chris S.

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            • #21
              This thread is DEAD ! Thanks for the lack of input !
              Happy Flying, Chris S.

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              • #22
                Yes, I think that we can trace the death of this forum to the change in format. Turns out that was quite the mistake. I appreciate those that run the mechanics of the forum, but there is zero doubt that the traffic on this site has absolutely cratered.....
                Brian

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                • #23
                  Originally posted by NoWingsAttached View Post
                  I have a thing about T tails. I built a wind tunnel to test all of the different tail designs for a pusher gyro back in 2008 thinking that a V tail would be great. I was right, although Ernie's cruciform tail is the best, the V tail is a close second, and the original Bensen design with the HS ahead of the VS is unbelievably stable! And I discovered the T tail stinks - it is by far the worst design of all, which tells me that anyone whoever designed a gyro with one did absolutely zero testing of models in a wind tunnel, quite obviously. And if they didn't bother to test aerodynamics of their design, what the hell are they doing designing and selling anything that flies and that my life depends on....
                  Apart from hear-say, what is your source of information?

                  A model of the ArrowCopter was tested in a wind tunnel. There were also extensive fluid dynamics simulations run on it. And it underwent a very stringent flight testing regime. And then I've been flying it for some 500 hours. And, believe me, stability testing was first and foremost on my mind.

                  The upshot: it is VERY stable with no adverse characteristics determinable -- it would not have otherwise passed certification. It was the first gyro to be certified in Austria and the authorities were all over it. Inside and out. They rode the rear seat during some of the crucial test flights.

                  The point is that you can't make a sweeping statement like this. I really wish you wouldn't just blabber on without knowing your stuff.

                  Greetings, -- Chris.
                  Read about my trip across the USA in an MT03 gyro here.

                  Comment


                  • #24
                    Originally posted by ckurz7000 View Post

                    Apart from hear-say, what is your source of information?

                    A model of the ArrowCopter was tested in a wind tunnel. There were also extensive fluid dynamics simulations run on it. And it underwent a very stringent flight testing regime. And then I've been flying it for some 500 hours. And, believe me, stability testing was first and foremost on my mind.

                    The upshot: it is VERY stable with no adverse characteristics determinable -- it would not have otherwise passed certification. It was the first gyro to be certified in Austria and the authorities were all over it. Inside and out. They rode the rear seat during some of the crucial test flights.

                    The point is that you can't make a sweeping statement like this. I really wish you wouldn't just blabber on without knowing your stuff.

                    Greetings, -- Chris.
                    Good to see I can still get a rise out of folks on RF, this place has turned into a ghost town and some lively conversation helps breath some life into the void.

                    My source of information is my home-built wind tunnel and my own observations, as mentioned in my post. Not sure how you could have missed that.

                    I will bet dollars to donuts that if the wind tunnel testing was done on the Arrow copter that it was undertaken in straight-line air, not rotational to properly model prop wash on the T tail in order to test the empennage for adverse yaw under power. It is very difficult to simulate well, unless that is specifically what you are designing the wind tunnel conditions for, as did I.

                    A whole bunch of gyros have T tails, and a whole slew of their owners love them - as you love the ArrowCopter. That's nice, but it doesn't make the T tail any better than being the worst design ever imagined for a pusher gyro. You are not wrong to love them, but the designers are mistaken if they think this is the best design for a tail and anyone who claims they are any better than the worst thing on the back of a gyro is mistaken. You folks can always learn how to fly it and deal with the adverse yaw - most especially when correcting for a bad landing while crabbing in a stiff cross wind. One good method is to land into the wind with zero roll. Another is to be sure the wind is on the opposite side of the tail as is the prop wash. If you get caught in a changing wind with your pants down, well, good luck friend.

                    Keep your spinny side up and your rubber side down.


                    GT Mills
                    Peachstate Rotorcraft Club

                    Mohawk Aero Corporation
                    PO Box 30133
                    Savannah, GA 31410
                    www.MohawkAeroCraft.com info@MohawkAeroCraft.com

                    Comment


                    • #25
                      Originally posted by Smack View Post
                      Yes, I think that we can trace the death of this forum to the change in format. Turns out that was quite the mistake. I appreciate those that run the mechanics of the forum, but there is zero doubt that the traffic on this site has absolutely cratered.....
                      Brian
                      I have no problem with the new format........works fine !
                      Attached Files
                      Happy Flying, Chris S.

                      Comment


                      • #26
                        Originally posted by NoWingsAttached View Post

                        A whole bunch of gyros have T tails, and a whole slew of their owners love them - as you love the ArrowCopter. That's nice, but it doesn't make the T tail any better than being the worst design ever imagined for a pusher gyro. You are not wrong to love them, but the designers are mistaken if they think this is the best design for a tail and anyone who claims they are any better than the worst thing on the back of a gyro is mistaken. You folks can always learn how to fly it and deal with the adverse yaw - most especially when correcting for a bad landing while crabbing in a stiff cross wind. One good method is to land into the wind with zero roll. Another is to be sure the wind is on the opposite side of the tail as is the prop wash. If you get caught in a changing wind with your pants down, well, good luck friend.

                        Keep your spinny side up and your rubber side down.

                        I don't want to step on anyone's feelings or ego so I apologize beforehand. I don't mnow your homegrown wind tunnel and the kind of instrumentation you have to measure forces, torques, position, flow etc. I also don't know whether you've done any fluid dynamics simulations on real gyros to identify weak areas in stability. And lastly I don't know how many hours you have flight testedthe ArrowCopter. But I do know what I have done in this area. And I do know that I habe observed none of what you are writing. So I can either throw out hundreds of hours of my own experience and knowledge as well as those of the team designing the ArrowCopter or be a bit sceptic about your claims.

                        I coose the former.

                        -- Chris.
                        Read about my trip across the USA in an MT03 gyro here.

                        Comment


                        • #27
                          Chris
                          Is the Arrowcopter still in production? I've heard lots of rumours that aren't worth mentioning here.

                          I balanced one recently in Germany, quite interesting.

                          Mike G

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                          • #28
                            Hi Mike,

                            yes, the ArrowCopter is in production again after a hiatus. As far as I know the lead time is 6 months at the moment.

                            Can you tell me more about balancing thenArrowCopter?

                            Greetings, -- Chris.
                            Read about my trip across the USA in an MT03 gyro here.

                            Comment


                            • #29
                              Chris
                              OK I'll send you a pm.

                              I'm told it was discussed on the German forum but I could never get to read anything when I tried to get on it, I wouldn't have understood much anyway, it's all in German
                              Mike G

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                              • #30
                                Originally posted by Mike G View Post
                                Chris
                                OK I'll send you a pm.

                                I'm told it was discussed on the German forum but I could never get to read anything when I tried to get on it, I wouldn't have understood much anyway, it's all in German
                                Mike G

                                Yes, here is the discussion...

                                ​​​​​​http://www.gyrocopter-forum.de/board...ten/#post20571

                                Apparently, and in this case, the vibrations in that ArrowCopter couldn't be eliminated. Things went better for a 'Calidus' that was also 'treated' by Mike, this time with success. From being a 'French unit' it was transformed into a 'German gyro'...

                                The whole thread is interesting and instructive. One of the posts mentions the subjective side of the problem, as some people may have a higher personal sensitivity to vibration, or perhaps they hold the stick more tightly... Who knows... It's clear that the matter is very complicated, that the 'stick shake' has many sources, and that they are not always in the rotor, or exclusively in the rotor...

                                My own ELA shakes wildly (at least I feel it that way...) but not always with the same intensity. It has 'good days' and 'bad days'... The last thing I've discovered is that the shake gets stronger when I push any of the rudder pedals. Hence, the vibration is probably originated there, and not in the rotor, at least in part... Who knows...

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