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Exadios

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Posts posted by Exadios

  1. No 'And?' answer... but a whole lot of small Clubs lost their investment in an ab-initio trainer-glider overnight. Blaniks had trained - to a good standard - possibly hundreds of thousands of pilots over the years. They were a decent thing to fly - albeit not sexy - and pretty cheap to run in the main. And they didn't kill people from nasty habits.About the best parallel I could think ( since Blaniks were the most populous glider produced), would be the total grounding of all C172's because one being used for a stunt plane had shed a wing. Possibly justified, but with huge consequences for GA world-wide.

    No doubt all of that is true. But what's it got to do will two gliders colliding at the WGC?

     

     

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  2. As far back as the original Discus most glider have had a tail tank. It is necessary because the water in the wings is in front of the spar and so forward of the CofG. If you add ~180l of water the CG moves a long way forward, still safe but detrimental to performance. The tail tank balances this out. When the tail tank is full there is a requirement to dump the water when the temperature gets to a certain value( i cant remember at the moment) lest the water freeze in the tail and cause structural damage. The small volume is prone to freezing before the main wing tanks. The temperature gauge is a required instrument if you use the water ballast.

    The temp given in the manuals is usually 2 degrees C.

     

    Some of the twins have a little more complex tail water ballast arrangements. For instance our club DG505 has two tail tanks - 'A' and 'B'. The 'A' tank is to compensate for the wing water as in the single. The 'B' tank is to compensate for the rear pilot. So the 'A' tank can be dumped but 'B' tank cannot - which is a shame because that implies that the rear pilot cannot be dumped either - ha ha.

     

    The singles are arranged so that tail empties faster than the wings so that there's no possibility of getting the C of G too far back. In contrast the DG505 has a system of actuator interlocks. In this case the wing tanks cannot be dumped until the tail tap is opened - and once it is opened it cannot be closed from the cockpit. So, once the pilot decides to dump all the associated tail ballast is lost.

     

     

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  3. Yep, it was a new tuggie - a croppie who'd been roped in as one of the usual guys was off sick. And I think I was about his third customer ever! Nice bloke; I went over and asked him if the tug was having problems ( I had though it must have, flying so slowly, which is why when what looked like a wing-waggle happened, I bunged-off instantly. He said 'No, I thought you guys didn't like to go fast?' It was a Pawnee 235 and had been bloody hanging on the prop, going up like a kite with me behind like a paper-bag on a string. And the Hornet felt like I was trying to tap-dance on top of a ball-bearing, very not nice at all. Yep, I knew my chaotic check, and thought I'd done it properly, but I wasn't aware of the peculiarities of the Glasfugel set-up. And, once strapped-in properly with no chute behind me, I couldn't actually reach the pull-handle for the pedals in the air, being somewhat of a short-ar$e in the arms department as well as the legs..

     

    Fortunately , I had had some really GREAT instructors who had taken safety very seriously and put me (and every pilot in the Club) through the hoops!

    'C'. :)

     

     

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  4. I have to say that I've not heard of using water ballast in the tail, but I'm not across all the latest developments. I do know that some competition pilots used to (carefully) ballast for the max. possible aft. c/g for themselves; John Rowe had done so for his Hornet, and I'm rather smaller than him. My check flight in his Hornet was one of the more 'interesting' flights I've ever had; the tug pilot climbed out at 50 kts and the Hornet wallowed along behind him like a drunken sailor, I had to pedal like buggery to keep it shiny-side up, didn't dare use ailerons.. Then at 800 feet, I thought the tug waggled its wings and bunged off somewhat gratefully.Since I didn't have any height and was not feeling all that comfortable about how it was flying anyway, I decided to see how well the brakes worked in case I had to outland the next day. Turned to line up with the cross-strip, pulled the brakes - they were excellent, my water bottle shot over my shoulder and down into the footwell. Then, as my weight came onto the straps, the in-flight adjustable rudder pedals decided to go forward for a look-see - I hadn't locked them properly in place.

     

    I had to swap from using secondary effect of rudder to using secondary effect of ailerons for directional control (evening up the wear, I suppose..) Got it all nicely lined up and then a guy on the strip, right where I had planned to touch-down, started to pull his glider across the strip in front of me without having looked back.. Brakes away again ( fortunately, Narromine has HUGE long strips..)

     

    Got it parked; John Rowe came over STEAMING from the ears ( I assume he'd watched the whole messy flight). 'What the hell were you doing there?" I apologised and told him that I'd lost the rudder pedals. He calmed down a bit, and then looked at me (sans a 'chute'), and said something on the lines of: 'Ah, bugger, what do you weigh?" I told him, and he went quiet, then said: 'Tomorrow, you fly with a chute, this thing is ballasted for me'.

     

    Then he went to have a chat with the guy who'd pulled his glider over the strip; I suspect it was a somewhat terse conversation.

    Aft CoG is scary. And 50 Knots is too slow. I'm surprised that the tug didn't have problems at that speed - let alone you. Do not let the tug fly slower than 65 Knots with water!

     

    WRT the rudder pedals no doubt that you've learned your CHAOTIC check since then. :)

     

     

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  5. When/how often do you dump the water?

    Whenever needed, but certainly before landing - which is why you often see the last of the water being dumped on final.

     

    The idea is to match the amount of water to the day. The stronger the day the more water. A typical competition tactic is to load more water than you think will be needed and, after testing the thermals, dump some before the start. This is because it is very difficult to add water while in flight. :)

     

    Also, as the day dies towards the end, it is common to dump some more.

     

     

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