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Good stuff Sam, I haven't seen that method mentioned previously, I thought I was having an original thought![^] It is of course suggested for balancing fin and pod by means of a profile picture.Unfortunately new recruits to gyros often want a "schmik" machine with a pod, which can make them directionally unstable if the fin effect is inadequate.LlewellaYou shouldn't push your luck. Play it safe and move the ladder..
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Good stuff Sam, I haven't seen that method mentioned previously, I thought I was having an original thought! It is of course suggested for balancing fin and pod by means of a profile picture.Unfortunately new recruits to gyros often want a "schmik" machine with a pod, which can make them directionally unstable if the fin effect is inadequate.As you can see I posted as Llewella again, but there is no facility on that page to edit or delete, so here it is again under my name.John EvansThink logically and do things well, think laterally and do things better.
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Sam,Sorry Sam, still cannot agree. The gust can come from any direction, and its the moment arm effect that you need to have calculated to determine the size and shape of your HS. (and your V fin component as well).The size of either is not about stopping the effect but having effective control over the gust. I strongly suspect that any simple 2 dimensional test will be misleading.Ted
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Ted,Beg to differ. The cut out method has been around for along time now and as stated by Sam and John can be used in vertical and horizontal plans to give you an indication of plate surface areas forward and aft of the Centre of Pressure. Refer Paul Bergen Abbotts books and other sources for this info. Whilst not an exact science, it is a good place to start.A point to note. Much discussion is made about whether or not a given HS is large enough to do the job required. Depending on the configuration of any given craft, the HS will be employed and fine tuned to help balance the static moments. (All the stuff about getting the longitudinal C of G foward of the RTV.)A vertical fin and a HS only has to be large enough to counter forward plate surface areas in order that the airframe will 'weather ****', track the relative airflow. This will give you a measure of dynamic stability.The size of the HS becomes more critical when dialing in the static requirements. If the HS needs to be big with substantial neg incidence due to a HTL and draggy nose down effect of pod, then so be it. But this is not necessarily the same size static HS requirement to effect an ADEQUATE dynamic effect.I think the length of the moment arm will be determined by the size of HS you settle for after you have used all the tools available to you to 'roughly determine' if what you have is close to what you need. The fine tuning will come with flight testing. Eg; Tall Tails Vs Magni Tri Tail. Horses for courses.Once again, this is just stuff I have read and am passing on as Sam has done. Hope this helps.Cheers,Mitch.www.thebutterflyllc.com
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Spot on Mitch !!!!!Ted There is no reason why you couldn't make your stab and rudder out of cardboard first, confirm its size by use of the photo cut-out method, then make the real thing.Only thing left would be the hang test.Regards Sam.
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Sam, I'll stick to mathematics rather than the cutouts.Ted
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Woz, What is the point of your comments? I never intended to do the calculations in my head. Have you been out in the mid day sun again?Ted
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Woz.... What ever you are taking, injecting, snorting, smoking eating, you'd better halve it.Ted
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Ted,Woz is a G junkie, which means he's addicted to A, can't help himself.Cheers,Nick.
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NickThanks for the heads up.Ted
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I caught Ozy-woz sniffing ether down on the engine threads
]Flying the right side up in Canada
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Woz, Have you had your fingers in the socket again?Ted
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