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Dec 03, 2005, 07:16 PM
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Levi Jordan's Avatar
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Soaring USA Thermik XL 4.0M F3J Sailplane

Well I just loved the looks of this airplane, so I had to get one.... I ordered it from Bob here at Soaring USA and it arrived a few days later with Fedex Ground in perfect condition.

Just a side note on shipping.... This was my first order from them, and I was IMPRESSED with the packaging. It was packed extreamly well, in one massive box! Everything inside was supported and padded very well.

The first thing I did was to slide the wing panels together.... just to "see" what it would look like finished..... Well I had to go outside to do that, because it was too freaking big to do in my living room! at over 13 feet, this thing is a monster!

Here are the specs on the ship:

Wingspan: 158" (4 meters)
Thermic XL 4M F3J Sailplane
Airfoil: MH32
Wing Area: 81.7 dm2
Wing Loading: 32.7 g/dm2 (+/-)
Overall Length: 68 inches (1700 mm)
Weight Empty: 84 ounces (+/-)
Weight All Up: 100 oz
Ctrl Surfaces: Ail/Flap/Rud/Elev (X-tail)
Battery config: 3300 NiHM 5 cell
Features: All hollow molded
Last edited by Levi Jordan; Dec 04, 2005 at 01:00 PM.
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Dec 03, 2005, 07:22 PM
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I started with the wing panels.... There is very little instruction on how to proceed, but I've been doing this for a while, so I just jumped in.... hopefully this thread will help some others in building.

The wings have 2 aluminum anti-rotation pins in the root panel.... these are not factory installed, so I started here.

Mark the locations of the pins... These were not provided, so I located the spars, and made sure I missed them (especially the rear spar) My location for the pins were 45mm in front and behind the main spar joiners.

STEP 2---
I located the holes 8mmvertically from the bottom of the wing surface, on both front and back pins.

STEP 3---
The holes were drilled with a .0625 pilot bit.... then final drilled with the correct .201 drill.

STEP 4---
The pins were glued in place with a fair amount of gorilla glue. It foams slightly.... just what we want to fill in behind the pins in the hollow wing.
Dec 03, 2005, 07:25 PM
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The next thing is to drill the holes for the pins to slide into on the outer panels. This was where the first small problem occurred. While drilling these to match the pins, the area where drilling had almost no micro balloon support behind it..... so I improvised.

- To locate the exact pin location on the outer panel, paint "White-Out" typing correction stuff on the 2 pins. Quickly slide the outer panel onto the spar and press the pins to the outer panel surface. This marks the exact location.

- Drill this out with a pilot (.0625) then to the correct size of .201.

-Of you drilled into good solid material, congratulations, your done. However, if it looks a little thin where the pins enter, read on.

- First coat the entire root, spar, and pins with a really thick coat of high quality pure carnauba wax (Boat shops) Repeat another coat after dry. Do not rub off.

- Mix up some epoxy and micro balloons to a thick slurry. Pour it into the 2 pin holes. The right amount should be about 2x the volume of the hole, for the length of the pin.

- Slide the outer panel onto the spar all the way so they are flush. Tape the LE and TE to keep them aligned. LET CURE FOR 24 HOURS. (No Peaking early!!!!)

- Wiggle the panels apart, they will pop loose very easily. use a short blade to remove any excess epoxy from the roots.

- The result is a perfectly molded, no slop wing joint.
Dec 03, 2005, 07:27 PM
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After the wings I went to the stabs. They are already molded with all joiner hardware aligned and ready to slide in place.

- The control hardware is all high quality ball end equipment. The Stab has 2 solid carbon joiners that attach and move it. A CNC machined aluminum ball fits over the rear joiner for the ball end.

- This had to be slid onto the joiner and then inserted through the side with the matching enlarged ball opening.

- Before sliding the joiner all the way through, I placed the ball end onto the joiner with the ball. This is done through the inside of the stab. It presses onto the ball with slight pressure. I used a brass tube to support the ball, and another to engage the ball end. It tapped right on with a slight hammer tap.

The Servo is a HS 5245MG. I machined the aluminum horn down to fit in the stab. I was happy with the fit, and it allows for full control range, and no binding. With dual ball ends it is also absolutly slop free. That was the most importiant thing to me.
Last edited by Levi Jordan; Dec 03, 2005 at 07:34 PM.
Dec 03, 2005, 07:30 PM
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I decided to move onto the nose section of the fuse next.

These come in 3 parts. The rear fuse, the inner nose, and the outer nose cone. The design is pretty cool, with lots of room, nice tray molding, and LOTS of strength. The Cone has a thick glass lay-up, with a beefy carbon band at the fuse/cone lap joint. It also goes beyond just sliding in place. It has a 4mm stainless steel bolt on the front of the nose cone that LOCKS that cone to the nose. It also will do wonders for strength!

Unfortunately I don't have an adjustable Tow hook yet..... so I'll get to that later.... But I did start the radio install.

- I choose to use the Digital HS 5245MG's on the Rudder and Stabs. The Stab Servo is tail mounted, so that left only one servo up front. The tray was molded for std size servos, so I was a little short making it to the rail. I opted to add a carbon bridge to make the fit. Thought it looked cool too....

- I wanted to get lots of flight time.... as the main purpose of this glider is for cross country and duration tasks.... so I custom built a 5 cell 4400 NiMh pack. I built it to fit right into the nose of the glider, leaving lots of room for my on board telemetry stuff. The configuration was 1 cell up front, then 3 in a bundle, then the last sideways across the back. Fits perfect.

- JR 770s PCM Rx gets the Velcro mount to the nose cone side.
Dec 03, 2005, 07:31 PM
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I went with Hitec Digitals on all control surfaces. I have been using Hitec servos for years, and just can't beat the performance and value. The New Digital 5125MG's are awesome! These went into the aileron bays.

The kit includes the brass ball end control horn, and being a heli guy, I appreciated that. I use ball ends where ever possible.

The kit also includes the CNC routed servo trays for all the wing and stab servos. The need about 1/8" taken off of them to fit the Digital servo, so I did that with a dremel and then Gorilla Glued them onto the top wing surface. If you haven't noticed, I like Gorilla glue. It's ability to bond to any surface and create a light weight, and extreme hold is awesome.
Dec 03, 2005, 07:43 PM
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Oh the flaps..... Of course I wanted to get the haloed 90 deg deployment.... so I spent some time testing different configurations. I departed from the pictured way of doing things here.

The Illustration shows a servo mounted to the top wing skin, with the horn down and the pushrod exiting the top wing surface to the control horn. This left you with a 3mm long control horn (sloppy control) a 45 deg. bent pushrod (sloppy control, no mechanical advantage) and a FATTY CARBON rear spar that had to be cut. (Weakening) I choose my method....

The Servo is mounted to the flap servo cover. These covers are incredibly thick and strong CNC cut fiberglass. My control arm is the full length aluminum arm that came with the HS 5245MG servos. The cleared the arm and control linkage above the rear spar, and also allows for 90 deflection. It keeps the servos mechanical advantage, and has absolutely no slop. The only penalty I pay for this install is the need for a custom linkage cover to conceal and streamline the longer exposed pushrod. This isn't done yet, I'm still making the molds. But they'll be carbon fiber and look pretty cool!
Dec 03, 2005, 08:01 PM
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jfrickie's Avatar
Nice build. I just got word from Bob about the Stratos I ordered. Nice to hear about the care he takes with shipping. Keep the pictures coming.
Dec 03, 2005, 08:26 PM
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Levi Jordan's Avatar
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got pleanty more....
Dec 04, 2005, 12:32 AM
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thanks for sharing the build with us.

why not just bottom drive the flaps and save making the cut in the wing ?
just curious.

Dec 04, 2005, 12:49 AM
Team WC2013 F3K
oakman7004's Avatar
Very nice plane. Actually i would like one myself so I'll follow this thread with interest.

Another benefit beside "bottom drive the flaps and save making the cut in the wing " could be reduced drag from the wing with bottom mounted linkage. For detailed info read under Aerodynamics/drag of Martin Hepperle hompage ,

Cheers Jonas Ekman
Dec 04, 2005, 09:29 AM
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I choose this method becuse the horn slots were pre molded into the top surface, and there was a molded control rod recess there too..... I figured it would all work out, then I started cutting, and ran into the problems....
Dec 04, 2005, 12:51 PM
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The rest of the ball links showed up, so I spent some time installing them. I'll have a little more cutting to do to clear on the flaps. Everything else fit great.

I used Titanium turn buckles on all stab and ailerons. I know it's a little overkill, but I had them laying around from an old racing truck project.
Dec 04, 2005, 12:56 PM
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Back to the electronics install....

The switch fit nicely on the cross section....

....and after a few hours of soldering, the DB15 plug for the fuse was ready to install. (allows connection for 4 wing servos to Rx)
Dec 04, 2005, 01:13 PM
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why do think they put the elevator servo in the tail, well i'm sure you get a nice stiff setup, but wondering how much nose weight this is going to take.

looks like will see soon
dave hauch

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