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Jul 29, 2011, 09:07 PM
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Build Log

Flair K8 vintage sailplane build progress


Well, this is the latest project. Been wanting to do a large woody sailplane for a long time now. If it's scale, even the better. Been searching for the K8 kit for many many years, as they've been out of production for a number of years. Finally found one . this is a BIG build project. The box was surprisingly heavy and stuffed to the top with lumber. But quality is very good. The plans and instruction are quite extensive and you have to pay close attention not to miss a step. The wings are build upside down, so what is on top of the wing has to be pin to the building board first and work up to the bottom next! I almost made a mistake already, but caught in time. **Click on this link to see the rest of the build**
Last edited by Sailhigh; Mar 20, 2012 at 11:47 AM.
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Aug 02, 2011, 07:27 PM
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Spar build


After tacking all the ribs (31 for half wing!), started the spar build. It's a large undertaking as the root is just over 2 inches deep and is heavily reinforced to take on the flight loads, specially at the root.
Aug 15, 2011, 12:57 PM
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Trailing Edge install


Almost 40 shear webs where custom fitted and installed between the top and bottom spar. The aileron sub trailing edge is installed and framed by two riblets, it will be cut out of the wing at a later time. False Leading edge has been spliced and glued to front of ribs. The lower sheeting for trailing edge (composed of top and lower sheeting) is now being installed. Good thing I bough extra cloth pins to hold the shape of the lower Trailing edge, as the lower TE sheeting has to form a concave surface when glued in place. Hope it works out.
Aug 25, 2011, 11:22 AM
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The first pics shows the outboard portion of right wing upside down, finally fully sheeted all the way to the tip (It's hard to take a good picture of the entire wing half which is 6 feet long). The wing can finally be removed from the building board and positioned upright. It's been a long process just to get here. Next the sheeting will start on the top of the wing. I got bored with the build so I jumped ahead and started working on the spoilers. The last pics show the spoiler/airbrake assembly.
Sep 03, 2011, 06:20 PM
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Added more sticks and plates to the upper side of the wing and spliced together sheeting to do the top sheeting. First I had to wire the wing as once the sheeting is done, there is no way to route wiring. Last pics shows the wing with top D-box and aileron sheeting done and the leading edge glued and basically shaped. Next is to cut out the ailerons, install the spoilers, add the wing tip block and add all cap strips. That is followed by a LOT of sanding. However I'm going to leave the wing as is and start the left wing and bring it to this stage and from then on work simultaneously on both wings. The spoiler installation instruction is non-existence so I'm going to do it my way, plus there are some pieces and bits of balsa that have to be added to the spoiler which I see absolutely no use for. I'll eliminate those and do it the way I've done on other sailplanes.
Oct 07, 2011, 06:17 PM
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The other wing is now built and brought to the same level of completion as the first. Though far from done, structurally they are complete. Remaining are spoiler installation, rib capping, aileron separation and wing tip block attachments, which will add another 6 to 7 inches to the wingspan. All that will need to be sanded and filled.

The second wing actually took less man hours to build than the first. I didn't follow the sequence of the manual. Since the wings are large, all span wise sheeting, spars, Leading edge and trailing edges, etc, have to be spliced twice. This time I did all the splicing first and then assembled the wing, as opposed to start assembly, splice, wait for it to dry, restart assembly, splice, wait for it to dry and so on, which wasted so much time.

I ordered spoiler and tow release servos and waiting their arrival. My smaller analog servos will not work with the ultra high rate signaling of FHSS-3 mode, though the large analog servos are fine. These will be the first digital servos I'll ever use. Hope they don't suck up the juice as much as the first gen digi servos.
Oct 14, 2011, 08:55 PM
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Fuselage construction


Well I skipped the tail feathers and jumped right into the the fuse.There are no plans for the fuse. Some of it is self jigging, the rest is not. A long perfectly straight line has to be drawn on the building board with normal lines drawn at set intervals and the formers have to be lined up with these lines to construct a perfectly straight fuselage.
Nov 24, 2011, 02:38 PM
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Fuselage continued


Most of the fuse is now done. There is more work left, but I stopped at this stage to build the tail feathers, which are already about half done. I have to take a break from this project to repair my 60" sloper which suffered massive damage when it decided to take on a fence!
Sep 30, 2012, 07:01 PM
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Back at it


After getting busy with a new job, and repairing a sailplane and building a new one in between, my progress has been spotty on the K8. However there has been progress. The tail feathers are built and ready for hinges and covering. The fuse has had diagonal bracing installed and a lot of sanding and shaping has been done. The nose highly modified to accept a new style, larger tow release mechanism.
Dec 09, 2012, 11:20 AM
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Tailplanes are covered and hinged. Fuselage servos installed along with push rod, pull-pull system and aero tow release mechanism.

Ka-8 R/C sailplane fuselage controls check (1 min 40 sec)
Last edited by Sailhigh; Dec 09, 2012 at 11:29 AM.
Nov 30, 2013, 08:36 PM
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Back at it again


After a prolonged period of inactivity, due to various life events, I started to work in earnest on the Ka-8 for the past couple of months. I set out to accomplish something every weekend, unfortunately weeknights have not been so fruitful, alas a lot was done.

Started back on the fuselage, bought some thin ply and made templates using cardboard for the sheeting and cut the ply to the templates. Bonded sheeting to front fuse. Cut and fit checked and cut and fit checked and repeated until the glass nose cone was good fit. Bonded nose cone to fuselage. Made canopy frame, cut the clear canopy and made numerous adjustments to fit canopy to frame, tinted canopy and bonded canopy to frame. No more could be done to the fuse, so work restarted on the wings.

Installed rear tube in left wing and sheeted over it. Installed root rib on both wings. Cut joiner box and rear tubing flush with root rib. Sanded the entire leading edge to shape. Took the spoiler assembly apart, since I thought it had too much friction and opend up some holes and reassembled and performed fit check. Cut out ailerons from wing and sheeted sub trailing edge and ailerons face. Attached wing tip blocks and sanded to shape (there is balsa dust everywhere!).

I stopped there for now. Next to install the spoilers and fit the servos.
Feb 17, 2014, 11:10 AM
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Almost There!


I've been pushing hard the past few months to bring this project to conclusion. The goal is to test fly in March. The airframe is finally done! In fact the wings and fuse have been mated, match drilled with fasteners installed. Wings and fuse rough sanded, spackled, and resanded multiple times to prepare for covering.

Actually during the last two weekends, the wings have been covered, and so are the ailerons. I'm on a steep learning curve with the SolarTex covering techniques. Never have used this material before, so there is a lot to learn. Won't be my best covering job, but it will do. Next task is to cover the fuse. I'm hoping that will go quicker as it's mostly open structure.

Now all the detail work remains to finish the wing. Cutting out the spoilers/airbrakes, opening the servo pockets and installing hatch covers, wiring, soldering, etc.

The nose weight is another issue to be dealt with. With an open frame, the weights have to be attached to the structure itself, rather than the nose cone, which is secondary structure. I already have a plan in mind for that and will have to wait for a fully covered structure and radio install to determine amount of lead needed.

On to the pictures,
Feb 23, 2014, 09:46 PM
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I can hardly wait to see the video on this one, Awesome.
Feb 24, 2014, 07:26 PM
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Me Too!
Mar 09, 2014, 08:19 PM
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Last 10% takes 90% of effort


That's old saying is so true. Though a lot of progress has been made, it's been very frustrating to say the least. A lot of things not going smoothly and it's pushing back the maiden flight. The pics below show the current state as was assembled for CG check. It looks ready, but there is a lot that needs to be done.
Last edited by Sailhigh; Mar 09, 2014 at 08:36 PM.


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