facthunter Posted November 5, 2015 Share Posted November 5, 2015 The plane is not rolling on it's axis which would be more likely to produce the effect we are talking about, but you still have positive "G" into the seat though as the aircraft is as if it's on the inside of a cylinder of a considerable radius. That is the only way it remains stalled. That's the way I see it. In any case it's unlikely to vent evenly, I would think. I've done plenty of spinning and never vented fuel, as far as I can recall. Nev Link to comment Share on other sites More sharing options...
DrZoos Posted November 5, 2015 Share Posted November 5, 2015 It may not have enough horizontal airspeed to produce lift capable of unstalled flight... but the pressure gradients and airspeeds of those wing tips are unknown an easily possible of producing vapour... what they lack in horizontal velocity, they may well have int vertical velocity and air flows... its not possible to calculate or rule in or out... but it is possible. Link to comment Share on other sites More sharing options...
pylon500 Posted November 5, 2015 Share Posted November 5, 2015 The plane is not rolling on it's axis I'm surprised when I find counter discussions on topics that are so blatantly obvious... The aeroplane may not be Rolling around it's axis, but it is YAWING around it's centre of gravity. This is applying a centrifugal force at all four extremities, that gains intensity as you move away from the centre in the four directions. The aircraft probably has wet wing tanks along most of their span, add that to a reasonable amount of dihedral, and it is possible to have fuel sitting in the root area (keeping the engine running), as well as fuel travelling towards the tips and exiting via the vents. The three points they are testing/making here are; 1. largish fuel load in a spin not having a serious affect on yawing momentum, which would delay recovery, 2. With four passengers on board, the aircraft is possibly closer to it's rearward CofG, which would delay recovery, 3. The four occupants are reasonably spread fore and aft which can also add to the yawing moment, as well as giving a tendency for the spin to go flat, which could put the aircraft into a deep stall situation, often very hard to recover from. Looks like the high aspect wings and long tail moment have added to the overall stability of the plane. ps, Yes, it's fuel...... 1 Link to comment Share on other sites More sharing options...
DrZoos Posted November 5, 2015 Share Posted November 5, 2015 http://www.sportskeeda.com/f1/wingtip-vortices-in-formula-one-why-are-they-formed All quoted from above... Now let us understand the thermodynamic reason behind the visibility of this interesting phenomenon. The basic assumption is that the whole process is an adiabatic process, with no heat exchange of the system with the atmosphere. So, according to the thermodynamic equation governing the adiabatic process, with an increase in pressure, temperature increases, and with a decrease in pressure, temperature decreases. The temperature we are talking about here is the temperature inside the vortex. Another temperature which we need to understand is the Dew Point – the transition temperature from gas to liquid, corresponding to partial pressure of water vapour – which determines when we will see the vortices trail and when we won’t. The Dew Point decreases with decrease in pressure, and increases with increase in pressure. After the formation of the vortex, the pressure inside it decreases significantly as compared to the ambient pressure. This results in a significant drop in dew point (which was already below the ambient temperature before the formation of the vortex) but along with it, there is an even greater drop in the vertex core temperature, which transforms the water vapour into water droplets and hence we are able to see the vortices trail coming out of the rear endplates. This phenomenon is more prominent in damp conditions because the relative humidity of atmospheric air is high. As more relative humidity means an increase in partial pressure of water vapour, therefore there is a rise in the local dew point inside the vortex. As there is no change in total pressure and temperature, therefore the vertex core temperature now is easily below the dew point, and hence the water vapour condenses. Link to comment Share on other sites More sharing options...
Nobody Posted November 5, 2015 Share Posted November 5, 2015 Zoos, I don't think that anyone is saying that under the right circumstances that a vortex of condensation can't form but that requires a very sudden and sharp reduction in pressure. F1 cars, 747s taking off or landing, fighter jets pulling up sharply. The wings in a spin are not working at high loads/pressures. Look at the flex in the wing. As the spin stops the wings flex much more in the pull out than during the spin. Why does the condensation disappear when the vortices are stronger at higher g loads? Page 15 of this link shows the layout of the cirrus fuel system. http://www.inetefb.com/Documentation/Cirrus/AMM/pdf/28-10.pdf Notice the vents from the outboard end of the tanks. These go to the underside of the wing so that in normal flight the higher pressure slightly presurises the tank. What do you think happens when it spins like a centrifuge? 1 Link to comment Share on other sites More sharing options...
DrZoos Posted November 5, 2015 Share Posted November 5, 2015 Im not disagreeing that it could be fuel.... it quiet possibly is Interesting the left wing vapour / fuel begins almost immediately and the right wing takes 7 spins to occur... could be different fuel levels in the tanks... could be different g loadings / airflows... or pressure gradients Link to comment Share on other sites More sharing options...
pylon500 Posted November 5, 2015 Share Posted November 5, 2015 Interesting the left wing vapour / fuel begins almost immediately and the right wing takes 7 spins to occur... could be different fuel levels in the tanks... could be different g loadings / airflows... or pressure gradients While I'm still positive that is fuel venting from the tips, the fact that the inboard tip started venting first, was a bit of a head scratcher? Can only assume that, in the act of stalling and dropping that wing, enough fuel fell to the tip to start a syphon action before any real centrifugal force had built up? Could also be that he just had an unbalanced fuel load. Link to comment Share on other sites More sharing options...
Guest ozzie Posted November 8, 2015 Share Posted November 8, 2015 I received a reply back on the video and yes Nobody got it right it is fuel venting. They also gave a lot of information on the aircraft that includes some excel sheets that I'll go through tonight. Some basic info comes with several power plants experimental fast build is a IO-390, FAA Utility FAR23 and EASA factory assist fast build is IO-540, Hybrid and full electric is in development and also diesel, they plan to fly these next year. 80 orders received and to book a production slot cost is 20,000 euro. Test flights available only at this time at the factory. Full prices on the excel sheets. If you order now delivery for Lyc models will Aug 2017 and certified models in May 2018. Link to comment Share on other sites More sharing options...
pylon500 Posted November 9, 2015 Share Posted November 9, 2015 I received a reply back on the video and yes Nobody got it right it is fuel venting ? See #28 and 32.... Link to comment Share on other sites More sharing options...
Nobody Posted November 9, 2015 Share Posted November 9, 2015 Pylon, "Nobody" got it right... Link to comment Share on other sites More sharing options...
pylon500 Posted November 9, 2015 Share Posted November 9, 2015 "Nobody" got it right... Yep, reading too fast, missed the capitalisation... "THIRD BASE!!!" Link to comment Share on other sites More sharing options...
fly_tornado Posted November 9, 2015 Share Posted November 9, 2015 Link to comment Share on other sites More sharing options...
facthunter Posted November 9, 2015 Share Posted November 9, 2015 So far I haven't seen a lot of evidence that many of you understand just what a plane is doing when it's actually in a spin. . Nev Link to comment Share on other sites More sharing options...
Nobody Posted November 9, 2015 Share Posted November 9, 2015 So far I haven't seen a lot of evidence that many of you understand just what a plane is doing when it's actually in a spin. . Nev Go on then Nev, If you know, enlighten us..... Link to comment Share on other sites More sharing options...
facthunter Posted November 9, 2015 Share Posted November 9, 2015 I have already explained in a previous post. The whole concept is not easy to grasp. A spin once it flattens is a different beast. The axis it is spinning about is not the C of G or anything like it The direction of the vapor from the tips gives a good indication of the way the plane is travelling through the air. Both show a helix the left one being a steeper angle, being closer to the centre about which the plane is descending in a spiral path. Nev Link to comment Share on other sites More sharing options...
Nobody Posted November 9, 2015 Share Posted November 9, 2015 The angle looks about the same both sides. Nev you haven't really explained anything. All you have done is contradicts and disagree with things I have said without really adding anything useful. Perhaps this will help you understand the dynamics of a spin and how the aircraft is rotating about a point fairly close to its center: 1 Link to comment Share on other sites More sharing options...
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