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#21
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John,
The Duo Tom Knauff was flying when we did our full boards dive off was a turbo version and thus heavier than a non-motorized ship. The DG-1000 I was flying had heavier pilots, so the payload was about the same. We agreed to this test before task opening on a day we had some extra time, because this notion that the Duo had inferior speed brakes had been floating around for some time and I wanted to see if it held any water. I joined up on Tom's right wing, less than a span away, and he pushed over, deploying full brakes and pushing the speed up to 80 knots. In this stabilized condition I had full brakes deployed in the 1000 and did not fall back as one might expect of a ship with better braking. As to the matter of tail weights, wheel brakes and gear configuration there are compromises with both approaches (long and short main gear). The old Duo's short gear was simpler, lighter and farther aft. This makes for easier ground handling but requires a nose wheel to handle max braking. The longer gear of the Duo X and DG 1000 keeps the gear doors cleaner, but is more likely to go on the nose if the brake is good. Speaking of wheel brake effectiveness, I've spent more time adjusting, bleeding, modifying and cursing the Duo brake than all other maintenance matters combined. Maybe my expectations are too high after years of flawless performance from Schleicher's Cleveland disc brake systems. Karl Striedieck "John Smith" wrote in message ... Karl Striedieck wrote: Is the 20 meter DG-1000 authorized for acro? With 20m it's authorized for "basic" acro, which means Loops, Turns and erect Spins. No rolls and no negative g. With 18m it's authorized for full aerobatics. If it is I'm curious about the reason. Both ships were designed to meet JAR standards regarding strength and dive brake performance. Because the dive brakes are *not* of equal strenght. I've never compared side by side, but the DG1000 definitely allows for a much more sloppy approach. (Not that I would advocate sloppy flying!) I've read that you compared them and think both are the same, I definitely don't share your opinion. |
#22
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I have some 300 hours in a Duo, and my experience is
that the Duo's brakes are more effective the faster you fly, compared with other gliders. Hence at the 80 knots used in the test that Tom carried out I would expect that the brakes would work well. It is at a 55 knot approach speed that the brakes are not very effective. My technique is that if I need to lose height, I put the speed up to at least 65 knots. This means a longer 'float', if the speeed is not reduced, but in general when doing a field landing the higher speed would mean that the approach could be made much closer to any hedge or other obstruction. This is a fundamentally different philosophy, from the suggestion that approaches in the Duo must be made at a constant slow speed. At 01:42 02 November 2007, Karl Striedieck wrote:John,The Duo Tom Knauff was flying when we did our full boards dive off was a turbo version and thus heavier than a non-motorized ship. The DG-1000 I was flying had heavier pilots, so the payload was about the same. We agreed to this test before task opening on a day we had some extra time, because this notion that the Duo had inferior speed brakes had been floating around for some time and I wanted to see if it held any water. I joined up on Tom's right wing, less than a span away, and he pushed over, deploying full brakes and pushing the speed up to 80 knots. In this stabilized condition I had full brakes deployed in the 1000 and did not fall back as one might expect of a ship with better braking.As to the matter of tail weights, wheel brakes and gear configuration there are compromises with both approaches (long and short main gear). The old Duo's short gear was simpler, lighter and farther aft. This makes for easier ground handling but requires a nose wheel to handle max braking. The longer gear of the Duo X and DG 1000 keeps the gear doors cleaner, but is more likely to go on the nose if the brake is good.Speaking of wheel brake effectiveness, I've spent more time adjusting, bleeding, modifying and cursing the Duo brake than all other maintenance matters combined. Maybe my expectations are too high after years of flawless performance from Schleicher's Cleveland disc brake systems.Karl Striedieck'John Smith' wrote in message h... Karl Striedieck wrote: Is the 20 meter DG-1000 authorized for acro? With 20m it's authorized for 'basic' acro, which means Loops, Turns and erect Spins. No rolls and no negative g. With 18m it's authorized for full aerobatics. If it is I'm curious about the reason. Both ships were designed to meet JAR standards regarding strength and dive brake performance. Because the dive brakes are *not* of equal strenght. I've never compared side by side, but the DG1000 definitely allows for a much more sloppy approach. (Not that I would advocate sloppy flying!) I've read that you compared them and think both are the same, I definitely don't share your opinion. |
#23
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problems@gmail wrote:
J a c k wrote: I think the Duo's airbrakes are better than many people think. The Duo is a big heavy glider with lots of inertia. It doesn't like to change direction quickly. That includes its behavior on sudden airbrake deployment. You don't get a lot of sink right away. My first reaction was that the airbrakes were weak but a little more experience showed me that with a little patience, the brakes took effect and produced a respectable decent rate. The Duo just makes you plan ahead a little more than with a light single seater. No, that was another to whom I was replying. Use care with editing, please. Jack |
#24
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Thanks John
I have a copy of JAR22, but did not read it well enough obviously. From other posts it appears that Schempp have now decided to apply for the certification. Since they have only just started building the first XLs I suppose we will have to wait a while. We will see how it flies in June 2008 I guess. John Smith wrote: Bruce wrote: The Duo passed the same JAR - now EASA certification that the DG1000 etc. did. That means they have to limit the speed to below Vne in a relatively shallow dive. (30 degrees) ... The no aerobatics certification appears to be simply a liability limitation. No. JAR 22 requires 30 degrees for all liders, but 45 degrees to be certified for aerobatics and cloud flying. |
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