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#1
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"CindyASK" wrote in message ups.com... We do practice that here. But many places do not practice for this. Full spoilers deployed ( to achieve symmetry) through approach, from the point of unlocking through flare/round out and touchdown. The typical error we find made by pilots in this configuration is the tendency to "hurry" on approach, with extra airspeed, and not understand how it will affect their glide slope. It should be much less of a handling worry to make the glider symmetrical, and control the approach in a regular configuration, than to begin to think of all the "different" things you could do to accommodate the asymmetry. Just because there are several stories reported here of pilots who either "didn't notice" their configuration issues, or handled them with aplomb, remember that this is frequently Not The Case for just as many others. We also practice/teach approaches with spoilers completely closed, but that is a different thread. Cindy B Caracole Soaring Good thoughts. Good also to keep in mind that many gliders will have the wheel brake fully applied with full spoiler deployment making the touchdown 'interesting'. Once, long ago, I tested the effect of asymmetrical spoiler deployment to find out if it would make a suitable roll control. I found that I could twist around in the seat of a 1-26 just enough to pull one of the spoiler cables behind the spar box. I was surprised to find that the roll/yaw effect was small - at least at normal approach airspeeds. As long as the airspeed is not too high, asymmetrical spoiler can be controlled with rudder and aileron. Of course, at higher speeds, the yaw from an open spoiler will overpower the rudder because drag is proportional to the square of the airspeed. Somehow, rudder authority doesn't increase at the same rate. Bill Daniels |
#2
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At 15:06 22 September 2005, Andreas Maurer wrote:
On 21 Sep 2005 21:16:29 -0700, 'Andy' wrote: You did better than a very experienced local club member who had the same problem many years ago in a DG300. He had one air brake open on tow, released early instead of gaining altitude and time, misjudged the approach and rolled it up in a ball. Hmmm... the DG-300 has fully automatic control hookups for the flaps. How could that happen? Bye Andreas The last DG300 I flew was standard Class, what flaps? |
#3
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On 22 Sep 2005 15:42:44 GMT, Chris Rollings
wrote: The last DG300 I flew was standard Class, what flaps? Ahhh.. sorry: I meant airbrakes. Bye Andreas |
#5
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Chris Rollings wrote:
I recollect once watching someone land an ASW20 with only one brake deployed. The pilot didn't even notice there was a problem, just wondered why one wing dropped a little earlier than usual. Lucky, I would agree. I too did an incomplete check and one brake on my ASW-20 came full open on tow. Though controllable it was easier to open both (the other) brake to balance the yaw force. After climbing to a suitable altitude I released and landed successfully using the "both" brakes method. As one can see there is a difference how to handle the case of one brake that won't deploy versus the case where the one brake stays deployed. Rudy Allemann |
#6
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I landed our ASW22A with one brake deployed. It had
been flown previously that day by my syndicate partner, without problem. Luckily I usually pop the brakes on the downwind or base leg just to check all is well. In this instance (at Dunstable) after a bang, the LHS brake deployed OK, but the RHS stayed down. There was a roll and yaw. I shut the brake(s) quickly looked again and the RHS was now open and LHS closed, with the opposite affect. Gulp, panic at thought of landing Open class without brakes, etc. Landing was just OK with a slight groundloop (stick forward and lots of brake (tail lifts, so no probs). The Hotelier for the brake had popped off after a previous flight. We used safetys after that with no further problems. 1) I still pop the brakes to check on base or final (and often just after settled into first climb). Cheap insurance. 2) On the assembly, I always give the Hoteliers a good tug to ensure they're WELL AND TRUELY connected. Stay safe. Pete. At 15:48 22 September 2005, Chris Rollings wrote: I recollect once watching someone land an ASW20 with only one brake deployed. The pilot didn't even notice there was a problem, just wondered why one wing dropped a little earlier than usual. Lucky, I would agree. At 04:12 22 September 2005, wrote: I committed one of the worst errors - an incomplete preflight check. I did not check the hotelier locks to the spoiler rods with enough care before takeoff. Coming into the pattern I extended the spoilers and noticed immediately that something was wrong. The glider (SparrowHawk) was pulling to one side and the rate of descent was not as much as I expected. However the glider was easily controllable. A few seconds and I saw that the right spoiler was not deploying. What to do? A couple of attempts to close and open the spoilers did not actuate the right spoiler. Then, oh well, lets check and see the effect of landing with only one spoiler. The situation was less dramatic than expected. Maximum sink rate was halved and the SparrowHawk needed some cross control to fly straight but no problem. The landing was easy and controllable. The lessons to be learnt from this are 2 fold: 1) landing a glider with only one spoiler should be easy for most pilots and 2) do a serious preflight inspection especially after assembly. Dave |
#7
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Guess I'm just unlucky as I've had this twice.
Many years ago in a Kestrel 19 the brake drive in one wing failed. Didn't even notice till I'd landed and saw one brake out and one in. Second time was test flying a club Grob Acro after C of A and rigging. It had some cosmetic work done on the brake slots. On the ground everything worked perfectly, it had a rigging check, DI, and 2 pre flights because we initially had a ground run cable break. On approach the brakes would not open, but did so after applying quite alot of pressure. In fact one opened and the other side wing pushrod bent. After repairs we tried again, after first getting a lot of people pushing up on the wings, the brakes were OK. Top of the launch, they would not open until we pushed over for some reduced G. It turned out that the cosmetic repairs had closed up the end gap which the caps need to move about 3 mm tipwise before opening, and the caps were jamming. It needed a lot of removal before they worked properly. The point is that there were no control problems whatsoever with one brake in and one out. Dave Salmon At 04:12 22 September 2005, wrote: I committed one of the worst errors - an incomplete preflight check. I did not check the hotelier locks to the spoiler rods with enough care before takeoff. Coming into the pattern I extended the spoilers and noticed immediately that something was wrong. The glider (SparrowHawk) was pulling to one side and the rate of descent was not as much as I expected. However the glider was easily controllable. A few seconds and I saw that the right spoiler was not deploying. What to do? A couple of attempts to close and open the spoilers did not actuate the right spoiler. Then, oh well, lets check and see the effect of landing with only one spoiler. The situation was less dramatic than expected. Maximum sink rate was halved and the SparrowHawk needed some cross control to fly straight but no problem. The landing was easy and controllable. The lessons to be learnt from this are 2 fold: 1) landing a glider with only one spoiler should be easy for most pilots and 2) do a serious preflight inspection especially after assembly. Dave |
#8
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In article ,
David Salmon wrote: Second time was test flying a club Grob Acro after C of A and rigging. It had some cosmetic work done on the brake slots. On the ground everything worked perfectly, it had a rigging check, DI, and 2 pre flights because we initially had a ground run cable break. On approach the brakes would not open, but did so after applying quite alot of pressure. In fact one opened and the other side wing pushrod bent. After repairs we tried again, after first getting a lot of people pushing up on the wings, the brakes were OK. Top of the launch, they would not open until we pushed over for some reduced G. Note to self: if brakes won't open, try a pushover to unload the wings. -- Bruce | 41.1670S | \ spoken | -+- Hoult | 174.8263E | /\ here. | ----------O---------- |
#9
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If one spoiler deploys and the other one does not, and it will not retract,
and it significantly affects landing, I expect that a forward slip, with the fuselage blocking the deployed spoiler (or flap) would be an alternative to try. At a time like that, you are glad you do not have barn door spoilers. Colin |
#10
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In 2001 I was sadly involved with the aftermath of
an accident to an SZD Junior. The BGA/AAIB inquiry found evidence that one airbrake had deployed (over-ranging and a broken drive gear) - the result was a spiral dive into the ground. Moves to test a Junior rigged so that only one brake deployed were vetoed (non-airworthy, so uninsured). A test pilot study of a range of glider types with one brake deployed would, no doubt, make interesting reading though. It is always worth visually checking the brakes if the glider develops asymetry during flight. It is also worth trying the occasional full brake landing, just in case. I wouldn't recommend practising no-brake landings though. Ray At 03:12 23 September 2005, Bill Daniels wrote: 'CindyASK' wrote in message oups.com... We do practice that here. But many places do not practice for this. Full spoilers deployed ( to achieve symmetry) through approach, from the point of unlocking through flare/round out and touchdown. The typical error we find made by pilots in this configuration is the tendency to 'hurry' on approach, with extra airspeed, and not understand how it will affect their glide slope. It should be much less of a handling worry to make the glider symmetrical, and control the approach in a regular configuration, than to begin to think of all the 'different' things you could do to accommodate the asymmetry. Just because there are several stories reported here of pilots who either 'didn't notice' their configuration issues, or handled them with aplomb, remember that this is frequently Not The Case for just as many others. We also practice/teach approaches with spoilers completely closed, but that is a different thread. Cindy B Caracole Soaring Good thoughts. Good also to keep in mind that many gliders will have the wheel brake fully applied with full spoiler deployment making the touchdown 'interesting'. Once, long ago, I tested the effect of asymmetrical spoiler deployment to find out if it would make a suitable roll control. I found that I could twist around in the seat of a 1-26 just enough to pull one of the spoiler cables behind the spar box. I was surprised to find that the roll/yaw effect was small - at least at normal approach airspeeds. As long as the airspeed is not too high, asymmetrical spoiler can be controlled with rudder and aileron. Of course, at higher speeds, the yaw from an open spoiler will overpower the rudder because drag is proportional to the square of the airspeed. Somehow, rudder authority doesn't increase at the same rate. Bill Daniels |
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