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#1
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Blanik L-23
There is a new Service Bulletin on the Blanik L-23 that requires
Magnafluxing the "U" shape bracket that connects the two elevator halves. The bracket on our ship had 3 cracks. If you have a Blanik L-23 and have not had it checked would suggest you do so. Losing half an elevator you might still have control. Losing both halves would probably be parachute time. For those that have had the check, are cracks being found? Duane |
#2
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"Duane Eisenbeiss" wrote in message news:HFIgc.24675$0b4.31395@attbi_s51...
There is a new Service Bulletin on the Blanik L-23 that requires Magnafluxing the "U" shape bracket that connects the two elevator halves. The bracket on our ship had 3 cracks. If you have a Blanik L-23 and have not had it checked would suggest you do so. Losing half an elevator you might still have control. Losing both halves would probably be parachute time. For those that have had the check, are cracks being found? Duane Hi We use the L-23 since 1992 for 'building pilots'! For this job it is the best thing you can have - cheap, handy on the ground to push back. Right, the sits are horrible, but if you take one of those nice special cushions under you buttom you can fly 5 hours (I made it once). I have about 400 landings as an instructor - but really folks if you want to fly long time and long distance there are better stuff around - ASK-21 or DuoDiscus or the big size Nimbus 3 etc. are more comfortable and with good performance. We had an L-13 for 30 years before and as I see the L-23 wouldn't receive this age. Maybe the T-tail is one reason. We also had to invest more work in this plane like mentioned above; it's not that robust like the L-13. But I think that we would do it again to buy a L-23 for instruction. Regards. |
#3
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I have two L-23 Blaniks at Marfa, Texas. No cracks in the elevator rockers.
Mine were built in 1991 and 1993. Maybe the guy welding back then was an old-timer who knew how to run a a good bead. For those who find cracks, Blanik America will replace the part for free. Vitek can give you all the details. All owners should have received his mailing of themandatory factory bulletin by now. This might become an AD in the USA, I understand it is already is an AD in Czech and Canada. Labor was less than two hours. The test cost $70. each part. Had to drive 3 hours to El Paso for a NDT facility, but that's where our nearest Wal-mart is located so it was not a wasted trip! PLEASE NOTE: YOU CAN PUT THE ELEVATORS ROCKERS BACK ON THE GLIDER UPSIDE DOWN - THEY WILL FIT BOTH WAYS! THE ELEVATOR WILL WORK, BUT NOT ENOUGH "UP" IF INSTALLED UPSIDE DOWN. IT IS EASY TO DO, SO MAKE A NOTE: "ROUND SIDE UP". IF YOU FLIP THE ELEVATOR / STAB OVER TO WORK ON IT, REMEMBER WHICH SIDE IS REALLY "UP". UP IS THE TOP OF THE GLIDER. YOU CANNOT MARK THE PART AS YOU MUST STRIP AND CLEAN IT THOROUGHLY BEFORE THE MAGNAFLUX TESTING. SORRY TO YELL IN ALL CAPS HERE, BUT THIS POSSIBILITY OF INSTALLING THE PART UPSIDE DOWN IS VERY REAL. ASK ME SOMEDAY HOW I KNOW. REMEMBER: "ROUND SIDE UP" - YOU'LL SEE WHAT I MEAN WHEN YOU REMOVE THE PART. |
#4
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Check the ras for an update by Burt Compton,
ZA. |
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#6
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Bruce, To clarify, the Blanik L-23 has a different tail design than the L-13.
The T-Tail elevator rocker arm easily reinstalls either way. "Round Up" is the key to make it right. The maintenance manual doesn't show it clearly, so consider it a 50/50 chance that the part (if no notes are made at disassembly) will be reinstalled incorrectly after the magnaflux testing for cracks. You cannot mark the part as it must be stripped of all paint and cleaned before the magnaflux testing process. The easy way is to know that the round side, not the flat side of the arm installs to the top of the glider. So "round up"! If the arm is reinstalled upside down, everything fits and looks fine, nothing rubs or interferes, but not enough "up" elevator. I hope this reassembly situation doesn't cause more accidents that the bad welds themselves! Just got word that FAA in USA is considering an Airworthiness Directive on the elevator rocker arms in L-23's. If it follows the factory bulletin, testing will be required before the next flight. Vitek at Blanik America will have all the details and replacement arms. Burt Compton Marfa Gliders, west Texas www.flygliders.com |
#7
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"Duane Eisenbeiss" wrote in message
news:HFIgc.24675$0b4.31395@attbi_s51... There is a new Service Bulletin on the Blanik L-23 that requires Magnafluxing the "U" shape bracket that connects the two elevator halves. The bracket on our ship had 3 cracks. If you have a Blanik L-23 and have not had it checked would suggest you do so. Losing half an elevator you might still have control. Losing both halves would probably be parachute time. For those that have had the check, are cracks being found? Duane No cracks on our L-23 (tested a couple of weeks ago) but it's relatively low time and not aerobatted. It's not clear at this point whether this may become a repetitive check. The reporting requirements of the SB will hopefully pinpoint any pattern of problems. I got a second hand report that something like 35% of the fleet in the Czech Republic had cracks (at least one you could see daylight through). There was a fatal last year there during an aerobatic flight. Possibly the part was contracted for or made in batches and that there are some bad welds. Frank Whiteley |
#8
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Possibly the part was contracted for or made in
batches and that there are some bad welds. Frank Whiteley With many cracked and many not cracked this sounds like a possibility, especially the made in batches part. As reported in my first post, ours had cracks but had never been submitted to aerobatic flight (at least not any that someone would admit to). Duane |
#9
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Overall not quite as good as the L13. The stall/spin isn't quite as
good as the L13, both of our L23's would drop one wing consistently and needed a bit of into spin aileron to hold the spin, wheras both our old beat up L13's didn't favour either wing at the stall and would hold the spin with neutral aileron. The L23 tailwheels looked stronger than the L13's but actually gave us more trouble (cracked bulkhead, bent tail fairing). I didn't find the control harmony as nice as the L13. Maybe the T-tail was a mistake. I notice that when they wanted to build an aerobatic glider (the L13AC) they returned to the conventional tail. Visibility, especially with the newer one piece canopy is superior to the L13. Ventilation? well nothing beats the windscreen scoop on the L13. The airbrakes are lighter to operate on the L23 thanks to the differentially sized upper and lower panels. We have had parachutes custom made for the L13 and L23 seats and these go a long way to alleviating the pain-in-the-back seats on them. We just got a new one with tip extensions to replace one destroyed in a storm but we haven't flown it yet. According to a graph in the maintenance manual the 6000hr. airframe life is reduced to 3500hrs. if the glider is always flown with the tip extensions in place. LET was selling us life extensions on the L13's but have recently stopped. If someone can explain to me exactly what structural problem results in these aircraft becoming unserviceable at a certain number of hours please tell me. At the moment I'm starting to think that LET just compared the revenue from a life time extension (a few hundred dollars) to that from selling a new glider. |
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