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![]() In my experience 'low maintenance' and 'robust' are more important characteristics in an ab-initio trainer than 'high L/D ratio'. IMHO trainers are all about compromises, the ASK21 is a very good compromise. You CAN get a trainer with 44:1 - But you will pay in price, ground handling and hangar space - to mention only a few. Why does Lasham have a fleet of K13s? Now if there was a way to get any glass installed as trainer at my club... We fly vintage Bergfalkes, and a Blanik because they are robust, repairable and cheap - not because of their L/D (all 30:1) or their control harmony, or aerobatic capability. Although the L13 is a great aerobatic trainer. My primary concern with the Puchacz/Perkoz design would be the big canopy frame obstructing the back seat pilot's vision. Never flown either, but it looks substantial, and right in the field of vision. If the list of woes below is accurate the Pooch would make a poor trainer. Fails the low maintenance test. Cheers Bruce Basil wrote: Having been responsible for the maintenance of a 4 Puchacz trainer fleet for some years and noticing that the fuselage is a Puchacz fuselage I hope they get the following bits sorted out before production. 1. They bungy sprung main undercarriage is awful. The Polish bungies last half a season. American ones last two seasons but are quite expensive and the design means that all the bronze pivot bushes are heavily loaded all the time and wear rapidly. 2. The spring cable reel that retains the canopy when open brakes every year and the glider is dangerous until it is fixed (the cable when not retracted can lasso the rear stick. 3. All the Polish wheels need replacing with Tost or Cleverland. The main wheel needs a disk brake. The bearing and brake arrangement on the Polish wheels is very difficult to maintain. 4. The plastic gears in the wing route used to operate the airbrakes cause a lot of backlash in the airbrake mechanism. They didn't work well in the Puchacz, Bocian, Jantar etc. Its time to change the airbrake mechanism. 5. The cables that operate the trim tabs in the elevator are single strand and not spring tempered. They are routed through the elevator hinge line and are flexed every time the elevator is moved. The factory ones fail every year. (replacements from the local model shop last several years but of course aren't approved). The Puchacz was almost a good trainer, let down by serviceability issues and being slightly too easy to spin. The Perkoz could be good if they would just fix the above. On Wed, 20 Jun 2007 17:00:29 -0700, wrote: SZD Bielsko is in the final phase of testing of "new" 2 seat glider designed for initial and advanced training. It will be fully aerobatic with 17.5 m wings and with 20 m wings it becomes pretty good x-c sailplane with L/D of 41.8. The reason I am saying "new" with quotation marks is that the glider was designed in the late 80-ties and bears name SZD 54 Perkoz. But the SZD Bielsko is working right now to bring the glider into production. http://www.szd.com.pl/pdf/szd-54_perkoz_doku_en.pdf Jacek Washington State On Wed, 20 Jun 2007 17:00:29 -0700, wrote: SZD Bielsko is in the final phase of testing of "new" 2 seat glider designed for initial and advanced training. It will be fully aerobatic with 17.5 m wings and with 20 m wings it becomes pretty good x-c sailplane with L/D of 41.8. The reason I am saying "new" with quotation marks is that the glider was designed in the late 80-ties and bears name SZD 54 Perkoz. But the SZD Bielsko is working right now to bring the glider into production. http://www.szd.com.pl/pdf/szd-54_perkoz_doku_en.pdf Jacek Washington State |
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Bruce wrote:
My primary concern with the Puchacz/Perkoz design would be the big canopy frame obstructing the back seat pilot's vision. Never flown either, but it looks substantial, and right in the field of vision. I've ridden back seat in the Puchacz once or twice. Rear vision is a bit restricted, but the main thing I noticed was internal reflections in that long, glass tunnel. There's one possible disadvantage that I'm surprised the nobody has mentioned: replacing Puchacz/Perkoz canopies is much more expensive than replacing K-21 or G.103 canopies due to the sheer single piece size. -- martin@ | Martin Gregorie gregorie. | Essex, UK org | |
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![]() "Martin Gregorie" wrote in message ... Bruce wrote: There's one possible disadvantage that I'm surprised the nobody has mentioned: replacing Puchacz/Perkoz canopies is much more expensive than replacing K-21 or G.103 canopies due to the sheer single piece size. Why would this cost more? Almost all glider canopies (made by Mecplex or Weiss in Germany who make nearly all current glider canopies) are molded in one piece and then cut in two for gliders like the K21 with separate front and rear canopies, so even if you only need the front canopy for a K21 you would be paying for the cost of both pieces anyway. tim -- Please visit the Wings & Wheels website at www.wingsandwheels.com |
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