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Old Nov 22, 2012, 01:47 PM
Dr John
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Lake Placid, Florida
Joined Dec 2001
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Build Log
Dr John's Yak54 UMX

This is a build log for my new micro Yak54 UMX kit. The kit is laer cut from 3mm Depron,1/16 ply and 1/32 ply. It also includes all required carbon fiber. This kit falls into the easy to build catagory and can be built by most beginer builders. It is however an advanced flying machine and requires at least an intermediate level pilot.

It is intended to use an AR6400 brushless Rx with two servos on the board. I am using gear salvaged from a v1 Beast. I am sure an AS3X board would work and make her even more user friendly but I have not tried it.

Wingspan = 16"
Lenght = 16"
AUW w/200mah 2s E Flight lipo less graphics = 60grs

http://www.youtube.com/watch?feature...&v=BVv4iVf7xKY

Thanks for looking
Dr John
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Old Nov 22, 2012, 02:24 PM
Dr John
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Lake Placid, Florida
Joined Dec 2001
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Begin the build

The first picture shows all the laser cut parts needed to complete the Yak build. Please note this picture has been intentionaly distorted. I have found it a good idea to leave the parts attached to the sheet until ready to use. This helps protect the parts and prevents losing them if your shop is as cluttered as mine.

Picture "build1" shows the three primary horizontal parts glued together and the spar installed.Unless otherwise noted all construction is being done with Beacon Foam Tac. Note: The cowel has built in right thrust, so when assembling upside down make sure the firewall surface is angled to the left. Cut a piece of .080 carbon rod to just under 16". Drag the end of the rod through to spar slot at an angle to compress the feathering left by the laser down into the groove so the spar will lay down flush with the surface and glue in place.

Picture "build2" shows the wing doubler with carbon rods installed. Two .040 rods 3.25" long lay in the rear grooves to stiffen the narrowest area of the fuselage. Two .080 x 1" CF rods in the front slots act as firewall anchors and should protrude from the foam just far enough to be flush with the front surface of the ply firewall. Note; The firewall is NOT glued at this time but is only acting as a locator for the rods while the glue dries.
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Last edited by pmpjohn; Nov 22, 2012 at 05:31 PM.
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Old Nov 22, 2012, 02:37 PM
Dr John
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Lake Placid, Florida
Joined Dec 2001
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Picture "build3" shows the wing doubler glued into position on the bottom of the wing. The CF rods get sandwiched between the two pieces of foam and a dab of glue applied at the rear ends of the .040 rods.

Picture "build4" shows the fuselage triplers glued into position one on each side of the fuselage.
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Last edited by pmpjohn; Nov 22, 2012 at 05:30 PM.
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Old Nov 22, 2012, 02:53 PM
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United States, MO, KCMO
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Looks Nice! Would be perfect for beast gear even though i don't have. Maybe you can make a lighter model out of 2mm around the same size for using the umx extra 300 gear?
keep up the good work though!
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Old Nov 22, 2012, 03:24 PM
Dr John
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Lake Placid, Florida
Joined Dec 2001
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Picture "build5" shows the elevator halves held in place while the glue dries on the .080 CF joiner. Note: When beveling the bottom leading edge of the elevator assembly the control horn slot should be on the port (left) side as shown.

Picture "build6" shows the ailerons and elevator hinged with blendrum tape. Cut a narrow slot in the leading edge of each aileron 1.25" out from the inside edge. Glue an aileron control horn into each slot pointing down. I use a small amount of white Gorilla glue for all control horns. The elevator control horn gets glued in pointing up.

I find it much easier to apply graphics at this stage while the parts still lay flat on the work bench.
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Last edited by pmpjohn; Nov 22, 2012 at 09:17 PM.
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Old Nov 22, 2012, 05:27 PM
Dr John
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Lake Placid, Florida
Joined Dec 2001
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Picture "build7" shows the two major subassemblies joined. Slide the fuselage over in wing from the front. Ensure all the tabs and slots fit together before gluing. Keep both assemblies at 90 degrees to each other while the glue is drying. I glue the front section back to the equipment bays first. After that is dry I move to the rear and glue those areas.

Picture "build8" shows the firewall epoxied into position. Make sure the small screw holes next to the CF pin holes do not get plugged with epoxy. As the epoxy cures you can push a pin through these holes to make sure they are clear.

Picture "build9" Bevel the port side of the leading edge of the rudder where it will hinge to the verticle fin. Cut a narrow slot in the rudder 1.5" up from the bottom and Gorilla glue in the rudder control horn pointing to the starboard (right). Hinge the rudder with Blendrum tape. You may now hold the airframe over your head and run around the room makeing airplane noises.

This completes the airframe construction. Next comes the installation of the power and control systems.
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Old Nov 23, 2012, 11:26 AM
Dr John
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Lake Placid, Florida
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Quote:
Originally Posted by Nooflyer View Post
Looks Nice! Would be perfect for beast gear even though i don't have. Maybe you can make a lighter model out of 2mm around the same size for using the umx extra 300 gear?
keep up the good work though!
Going from 3mm to 2mm will not save all that much weight. A lot of the weight in Depron is in the surface "skin". In the thinner sizes a lot of it's strength comes from that same skin. Is the Extra a UMX or a UM? If it is a UM with a one cell brushed motor, all the gear will need to move forward to get the CG right. At this time I do not have a place to fly indoors. During the winter in Florida days calm enough to fly one cell birds outdoors are very rare. Thanks for your input.

Dr John
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Old Nov 24, 2012, 09:04 AM
Dr John
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Lake Placid, Florida
Joined Dec 2001
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Power and Control

Picture "build10" shows the motor screwed to the firewall. If your doner was a Beast the mount you have fits the firewall without modification. If you are using the 180 motor from a different UMX model you may need the Beast mount. This mount is available from HH part # EFLU4066.

Pictures "build11" and "build12" show the Rx board mounted in the upper equipment bay. I use a few drops of hot glue to secure the board in position. Two small holes need to be cut through the wing as shown to pass battery and servo wires through.
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Old Nov 24, 2012, 11:06 AM
Dr John
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Lake Placid, Florida
Joined Dec 2001
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Pictures "build13" and "build14" show the aileron servos hot glued into position. I have chosen to use a pair of HK ultra micro servos on this build but the E Flight linier servos would be installed in the same position. The HK servos require the connectors to be changed to plug into the Spekrum board.

Picture "build14" shows the excess servo wires and"Y" connector folded up and tacked the the fuselage with a dab of hot glue.

The control rods are made from two pieces of music wire with a "Z" bend on one end of each. They are joined with a lenght of 1/16" heat shrink tube after the servos and ailerons are centered. I use a soldering iron to shrink the tube
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Old Nov 24, 2012, 11:39 AM
Dr John
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Lake Placid, Florida
Joined Dec 2001
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Picture "build15" shows to rudder being clamped into position while the last piece of heat shrink was installed on the control rod. Rudder and elevator control rods are made using "Z" bend wire ends and a .040" carbon fiber rod. After flight testing to be sure trims are OK a drop of CA should be applied to the shrink tube joints to ensure they remain fixed in position.

Picture "build16" shows a piece of Velcro installed in the battery box.

Picture "build17" shows a 2s 200mah lipo in postition on the Velcro

If everything came out right the plane should balance at the front edge of the spar. Control throws will vary depending on pilot skills and flying style.

Enjoy
Dr John
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Old Nov 24, 2012, 11:41 PM
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Old Nov 26, 2012, 08:29 PM
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United States, FL, Sebring
Joined Feb 2006
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My airframe is together, now I just need to get the appropriate servos. I'm not going to use the stock linear servos when they are exposed to the elements like this. I could use the brick and servos from the GP F-86 but I was hoping to save those for one of your other kits.
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Old Nov 26, 2012, 10:39 PM
M16 CIII/AR15/FN 2000 and PS90
Denile's Avatar
United States, AR, Waldron
Joined Jan 2005
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Hey pmpjohn where did (do) get those 3 wire connectors you used on the Motor to ESC.
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Old Nov 27, 2012, 08:38 AM
Dr John
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Lake Placid, Florida
Joined Dec 2001
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Quote:
Originally Posted by Denile View Post
Hey pmpjohn where did (do) get those 3 wire connectors you used on the Motor to ESC.
www.sparkfun.com
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Old Nov 27, 2012, 11:21 PM
M16 CIII/AR15/FN 2000 and PS90
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United States, AR, Waldron
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I hate to ask but after looking for a bit, could ya give me a hint on which satagory to look in..
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