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jules · Posted: Wed Aug 29, 2007 1:41 pm Post subject:

Hi Guys, and thanks for the update Nev.

Have heard about Sam; send him all the best and very glad his accident has not led to anything more serious.

VR tuck eh? Well strong enough conditions would probably do that to most machines...incidentally Tony Anderson is a training captain on Airbuses and flies happily (a phantom) without a tailplane..so its a matter of horses for courses...

Anyway go safe guys and apply your own safety rules not that of the pack...I know you'll do that anyway.

heres to light winds and big thermals..

Jules

Pauline · Joined: 23 May 2006 Posts: 289 Location: Oxford, UK

Ever since Keith Cockcroft I've had reservations about the mountains....

Randombloke · Joined: 28 Mar 2006 Posts: 260 Location: Kent, UK

Tony Anderson · Joined: 18 Aug 2006 Posts: 57

Here, Here Steve could not agree more,if you ask a Boeing pilot would he fly a Airbus he would probably say no. Such are the preconceived prejudice that supposed enlightened people have built up around them, lets not taint new pilots considering entering the rigidwing arena that a tail is the be all and end all of selecting a rigid .

nev · Posted: Fri Aug 31, 2007 11:26 am Post subject:

nev · Posted: Fri Aug 31, 2007 12:56 pm Post subject:

......two years ago, there was a get together of pilots after the pre-worlds (Florida, 2005). It was interesting to hear that top Austrian Robert Reisinger (RW World Champion, and recently 2nd place in Flexi Worlds) said, first hand, that he believed flex wings would benefit from the use of a tail. He was clearly impressed about the difference it made.

But it may not be practical to 'tail' a flexi - the reasoning I heard recently is because the wing changes shape and hence the tail incidence would need to change too. However, I believes Roberts reaction independently demonstrates the virtues of a tail - and before anyone misinterprets what I'm writing, I'm neither 'flexi bashing' in this example, I'm just extolling the merits of a tail/fuselage. Disclaimer added as (you never know) there may be some senstive Flexi pilots straying into this forum.. Wink

My point is that St.Andre can be an extremely lively place to fly and given the increased risk of well-above average turbulence I wouldnt go there without a tail, but hey, just an opinion, and this is a forum............
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Nev

Tony Anderson · Joined: 18 Aug 2006 Posts: 57

More to the point how are things going over in St Andre.

nev · Posted: Fri Aug 31, 2007 6:04 pm Post subject:

Wednesday was cancelled too, overcast with light rain.

Thursday/Friday looked poor, so Geoff and I returned to the UK. I am mid-house and job move, plus Geoff runs his own company so we both had compelling reasons to put the time to better use.

From the synoptics, the last few days were due to be windy-ish. When it comes to wind, I'm setting my upper limit of wind in big mountains at around 8-10Mph, and it looked like it'd be windier...

Darren Blackman bruised his foot landing his pre-comp, and is strapped up unable to fly. Mike Stephens is doing well on his Phantom, had an upright/basebar go *&^&* on landing on the first day (St.Andre landing field is a bitch), but on subsequent days was able to borrow Darrens as he can't fly.
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Nev

Randombloke · Joined: 28 Mar 2006 Posts: 260 Location: Kent, UK

Pauline · Joined: 23 May 2006 Posts: 289 Location: Oxford, UK

Tail fins are now fitted to Cheetahs for lateral stability. Would these prevent a spin from developing I wonder?

Stiker · Joined: 24 Apr 2006 Posts: 79 Location: Peaks

Hi guys some more notes from St.Andre, after Nev left the predicted winds and cloud vanished and we have had two good flying days. Yesterday (thurs) we flew a 58Km three turnpoint race to the South near lachens, it was a much more benign day with good clouds to show the way. Jacques on the VR did it in 47 mins...Paul Harvey and I chased him but my RVG has not worked since bending my basebar, leaving me a max glide speed of 80kmh - not enough. It was blowing 10mph SW today and was fine on course but more turbulentif you went off route via th St Andre lake.
Today (Fri) we flew to Laragne, or to be precise Jacques and a French flex pilot did, the rest of us got stuck in the valley before sisteron (oh for a functioning RVG). The wind was again 10 mph but W with a NE component above cloudbase. Bouncy but not turbulent.
The last two days have been much clearer air with no low level inversion.
Tomorrow is supposed to be lighter winds and good thermals.(Sorry Nev)
I have been impressed by the phantom in turbulent air, it definitley feels safer the more bank you have on.
I spoke with jacques about the VR/Phantom debate and his ideal glider would be a Phantom with Spoilers!! I will explain more when I not posting via Balckberry. Mike

Tony Anderson · Joined: 18 Aug 2006 Posts: 57

Phantom with spoilers !! what did I tell you Boeing pilots know sh*t, who,s prejudice?. Good to here the Phantom is working well, no chance of spinning out of high bank turns ,good luck. Tony.

nev · Posted: Sat Sep 01, 2007 9:08 am Post subject:

jollyveg · Joined: 31 Aug 2007 Posts: 2 Location: evesha Uk

When I wrote the article about tailplanes it followed a St Andre league when several tumbles ocurred which included Ron Richardson, so nothing changes.
Joe Scofield added a couple of addendums to the article, one written by Dr Bill Brooks. This discussed tip rigidity and put forward, as I remember it, that a solution to this would go a long way to solving pitch stability problems.
The Phantom has addressed this issue in that the wingtips are absolutely rigid. The sail cannot wash in or out at all. This is in complete contrast to the Atos VR where the tips are not rigid at all. Consequently the Atos needs a tailplane the Phantom does't.
In respect of flexwings we ( working with Cookie and Tony Lucchesi )found that the handling of the glider, particularly in thermals, could be improved by adjusting the "cut in" angle of the tailplane i.e. by making it more negative relative to the main wing. However this made bar pressure at speed too high. As the negative lift force created by the tailplane at thermaling speeds is relatively low compared to the force created at inter thermal speeds I incorporated a speed sensitive stop into the tailplane pivot system. This alowed the negative angle of attack to reduce at higher speeds thus reducing bar pressure which made inter thermal gliding less strenuous.

In the years since I stopped work on tailplanes support at the tip has vastly improved with wire stabilised sprogs and the planform of the wing changed to move more area tpwards the tip to proved more rotation damping.

So to conclude, tailplanes make gliders without rigid tips safer and probably still can be engineered into a flex wing glider with additional benefit to handling and little penalty on glide. The Phantom because of its completely rigid tip design doesn't need a tailplane and by the way I own one.

John Vernon