Shape of tail feathers

[asra]

Allan, Thanks for your support, however I must take up one of your comments."I guess the bottom line is what works, works, and who really cares why." Sorry but I do, I have a strong desire to understand why and more importantly why it doesn't work, its as simple as that. You are going to get sick of my questions but in the end I will have a reasonable understanding of how a gyro flys and how to fix something if it doesn't. When I look at the different gyros on the market I want to be able to spot the differences and know why they perform the way they do. You never know, I may even down the track, decide to become a TA, then it'll be because I've got something realistic to offer back to those in the sport.So I'm here to learn anyway I can. I really do thank you for your posts.Ted

[Waddles]

Gidday Ted,You have a right to care. The very difficult problem is that there has been very little modern research into what works and what doesn't. Most of the information out there is opinions, and they are not always correct with all types of configurations. Now, you will be baffled by theories and formulae, but who invented these, and why are the specific constants used in some? Probably because there was definitive testing on one specific set of circumstances, and therefore it was assumed that these parameters transferred across to everything. Not correct in my opinion.Having found a configuration that flies safely and well, it is difficult to apply a lot of the current hypotheses to that design. I recall a thread of some time ago that knocked the heck out of a Rosco machine, yet, there are a multitude of these designs flying very successfully without significant problems. Hence my statement, what works, works. Now. If you can come up with a theory why a Rosco is stable, yet it should not be according to some, that's good. Don't know what it's called, R&D or whatever, but the proof is in the pudding, and as a result, in my opinion, no TA can look at a machine and definitely say it will or won't fly safely.Ted, this medium is supposed to generate queries and discussion, so your disagreement, put the way you did is welcome.Keep up the good work.Waddles.

[asra]

Alan, I note your comments. There are many examples of aircraft that the general public thought couldn't get off the ground yet they did in fine style, and I guess if we looked hard enough we'd find examples of aircraft that someone proudly annouced as a "goer" yet it failed to finish its maiden test flight.If we develop an inquiring mind... well we could near do the impossible. Cant we?? I have enjoyed your posts as its breathed some extra zip into the forum.Ted

[asra]

why not?[]salutations []André Martin.Québec; CANADA.

[Brian]

Ted, always good to see people looking outside the box however, I'm sure that it would help a lot if you had a few hundred hours up and had flown a few types of gyros so that you had an idea of what you are looking at.I'm very interested in tail feathers and some of the latest designs are pretty good looking. The winglets or tips on the stab of Stans Gyro is a pleasure to look at. Just an opinion but I reckon the tailplane needs to be back a bit on the tall tails. Brian

[asra]

Brian, You are limited in so far as placing tall tails further back. Consider the normal rotor reach then add a flap dimension and you are going to end up slicing your tail.Ted

[Brian]

Ah huh, thats right Ted and there's one reason tall tails are limited and when I get a new 2 seater built, it will have a conventional tail with winglets !!Its interesting as I fly a Rosco built gyro which in some quarters is looked upon as 'unstable' with a conventional tail and stab that he puts on his gyros and have racked up a fair few hours with not one hint of all the dangerous things its supposed to be capable off and just from my experience, I dont think tails and their shape really make all that much diference as long as it has a stab and rudder although some have and are still are, flying without any stab and maintain they feel very happy with their set up. It does seem that when you put a 2 seater pod on, you need additional winglets to keep the gyro from 'wagging its tail.' Rosco has built a bigger stab and I have ordered one just to see what the bigger stab will do to my gyro.Brian

[asra]

André,Just a brief thought re the ducted fan concept or more so the one you posted is; Is there sufficient horizontal surfaces given that there's an additional vertical fin centrally located?With the long pod acting on one half, it would be interesting to see the performace figure of the ducted fan.Ted

[asra]

Brian,Any chance of an umclose pic of your machine?Ted

[Brian]

Hi Ted, sorry its taken so long to have a go at putting a photo in but going to give it a go , just for you.Image Insert: 65.77

[Brian]

Hooray, it worked!! Will try another photo from a different angle.Image Insert: 50.55

[NiqueNaque]

Brian / Ted,You will note there is a reasonable coupling on the tail, ie, a fair distance to the tail from the mast, unlike a tall tail with its usual short coupling.A longer coupling makes the tail far more effective, but you already knew that..Cheers,Nick.

[asra]

quote:Originally posted by NiqueNaqueBrian / Ted,A longer coupling makes the tail far more effective, but you already knew that..Cheers,Nick.A longer moment will make a tail of the same area and airfoil more effective than that same tail with a short moment. A larger tail with an airfoil fully immersed in the prop stream will be very powerful, however, even with a shorter moment.

[asra]

Now that everyone seems to be thinking 'outside' as well as 'inside' the box, how about something that could be considered under or on top of the aforesaid box?It seems accepted that one of the advantages of the tall tail is its acting a a flow straightener, cancelling out torque and giving a little 'lift' that adds to thust. If the mast, and perhaps the landing gear legs on a tractor gyro were suitably faired, could they not also act in the role of a flow straightener? Perhaps they would also be assisted in this by the fuselage being flat sided. Obviously their directional destabilising effect [due to being ahead of the C of G] would have to be overcome by the tail.John EvansThink logically and do things well, think laterally and do things better.

[NiqueNaque]

How is John's tractor gyro going?