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Old May 11, 2014, 09:46 PM
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United States, CA, Chino Hills
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L-39 Kit bash from HET

Well I got a ARF/kit and I had read hear about some of the points people had brought up.

Well, first of all this airplane is supposed to have wings glued to the fuselage. So rather than leave the monokote attached I opted to heat and peal the coating of the wings. I wanted to address the issue of the odd bevels on flaps and ailerons. So rather than go crazy having to reshape I skinned the top of the wing with thin ply to close the gap on the flap. Also being that the aileron is design for top hinged the way it is manufactured I did do this but again using the top thin ply skin to seal the top surface.

Ultimately this will allow me to fiberglass the wing and seam the wing to fuselage and also to the wing tanks.

Need to get a hold of CST for a new carbon rod for the wing. Would like it just a little longer than the gear area.
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Old May 12, 2014, 09:28 PM
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I also picked up one of these recently. Wing tube does not bear on any wing ribs, just a hole in a balsa block. The ply retract mounts are glued to the same balsa block, no attachment to any rib. Both of those seem weak, are you planning to modify these areas. At 10.5-11 lbs I don't see this holding up to the grass field I fly from. I do agree the wing tube is too short. Would be better extending further into the wing and picking up on a couple of ribs inserted into the wing.
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Last edited by 172AMD; May 12, 2014 at 09:36 PM.
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Old May 12, 2014, 11:35 PM
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Looking at the wing

The gear blocks as you mention are put in with a elastic type glue. As I needed to clean the blocks for fitting the gear into the bays. My plan is to use fiberglass cloth and anchor the block to the sidewall in the gear bay area. As for the Wing rod I have a solution for the rod now. Just need to address the contact points if any beyond the foam the wing is made of. This over time without support I agree will be an issue so a rib or partial rib with a hole glued along the carbon support will be helpful and prevent the sag or flex that can happen under load without support.

Of since this wing is permanent, I could cut in spars but would have to make sure that I'm not going to hit the wheel wells.
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Old May 13, 2014, 01:20 AM
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Here are some images

Still need to route line for servo wires. I'll just insert some fishing line or so some type of rod to pull wiring in fuse when the time is needed.

Well I think it's glassing time on the wing aspect.

The stab and vertical still need sanding. The gloss that was on it has all kinds of runs and other stuff. I will be gluing the stab on as well as the vertical will be glued on. I've made a simple post so far. Still would like to create a arch on the top of fuse to tie into the vertical stab to provide support and also help reduce fuse flex.
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Old May 17, 2014, 04:13 AM
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Bash and Glass

Wings getting some glass action.
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Old May 19, 2014, 11:01 PM
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Reducing some flex

A little more work. Hinging done on the stab and vertical. Also mounted the servo in the stab. Added some carbon to the sides of fuse to strengthen the stab mounting location. Also extended the short spar in the vertical so that it can be tied into a former to again make tail a little more solid. I need to fab a motor mount and then the tail section is almost complete.
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Old May 20, 2014, 12:48 AM
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Quote:
Originally Posted by jefffassbinder View Post
Wings getting some glass action.
good idea.

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Old May 24, 2014, 12:37 PM
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Former sized

Well I cut some Formers for the rear of the fuselage. In addition, I've made a vertical brace for the rudder and also sized the fan formers. I'm going to be using a JF90mm on this airframe. I might employ the mod that CN talked about on the ducting in order to pull in more air.

Horizontal stabilizer has been glued on now. Will let this setup and then fill and seem the bolt hole location.

Now finish vertical servo installation and then once that is in I will mount the vertical fin and make sure I'm 90 and then I will flip over and install the formers to support horizontal and vertical.
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Old May 25, 2014, 02:13 AM
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Vertical in place

Now to fill and sand the tail section. Motor mount will go in when I have another JF90mm on hand.

Im thinking 8s 5000 or going 12s 3300

A lot less flex when putting pressure on the vertical. Without formers the fuse would flex in the tail section. Now with formers inlace the vertical can really be pressed upon while gluing. No distortions.
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Old Jun 10, 2014, 03:06 AM
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Hatches and new Covers

Well the stock cutouts don't have much of a setup for servos so I created a few hatches from birch and tossed the plastic hatches supplied. I also inserted a inner plate surrounding the hatch opening to strengthen the hatch mounting area. I was at first going to drop a ply plate in and then mount but decided to toss the plastic and use the hatch covers as a servo mounting location.

Well wiring is in place and servos are centered and programmed at this point. Still need to create some linkage rods. I'll install gear just to get fit and then remove for prime.
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Old Jun 21, 2014, 10:15 PM
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Almost time for some prime

Here are a few photos of wings attached, and servos mounted. Just need to finish sand and then prime. Once in prime decide on my scheme.
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Old Jun 23, 2014, 02:00 PM
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Prime Time

Well went to watch the Scale Squadron Event so didn't work on it much the other day. But it's time to bring out the primer and then do some finish sanding. Need to pick up another JF90 for this model. I have a new HET fan but I really like the performance the JF puts out.
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Old Jun 26, 2014, 01:53 PM
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Scale Squadron Event

Well here is a picture of Bob winning second at the Scale Squadron Event with his very nice BVM Fury.

Also here is some prime action. It's a double header going on! Oh ya, lots of sanding to be done. Paint is coming soon!
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Old Jun 27, 2014, 01:55 AM
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First sand layer

First sand layer
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Old Jun 27, 2014, 12:23 PM
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Orange, California, United States
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Nice Jeff

Your really moving along on your build .

Mark
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