Planeprint Learjet 35 : 50mm

[Michael]

Windows installed and gyro set up.

Ready to fly.

[davidk]

X-Fly makes a Reserve Metal Gear servo so I used a Reverse and a Positive for the Elevator.  With notches cut I'll hot glue these into place and try some yellow electrical tape over top to make it look pretty.  Using a Reverse servo I can "Y" the servos together and not waste an Rx channel.

For the Ailerons I used 2 EMAX ES08MAII 12g Metal Gear servos with a "Y" connector.  These just fit with a printed 28mm x 28mm x 4mm base to make it level with the wing surface.  Again, a bit of hot glue and some tape to finish.

With the Throttle, Rudder, and Gear, that leaves me with 1 open channel on an AR620... just in case I decide later to use the flaps.

[davidk]

The Tail is done.  I'd have to call it persnickety.  Sizing down makes some stuff too small.  But, time and patience, and a lot of tiny dropped screws... and she looks very pretty.

[GuyOReilly]

Looks fantastic! 

[msatin]

Very nice indeed!

[davidk]

Learjet 50mm coming along.  Nacelles on, hatch done, and finally settled on a shade of green for the wings and windows.

[Michael]

So nice!

[piker]

Oooo  I like the green!

[davidk]

Landing gear is in.  The downsized main gear mounts were a little thin so I re-worked them so they are beefier, take a good sized screw, and fit the contours of the retract.  They glued in solidly to the wing.  The main gear retract is the same 25g as in the nose but with static wheels.

Here's one of those things that makes me shake my head.  The retracts with wheels are sold in 2 different configurations... and they've been like this for many, many years.  You get to choose "A" or "B", the difference being which way the wheel is turned.  Let's say the Learjet needs Option A with the retract running parallel to the wing and the wheel positioned appropriately.  The grub screws that tighten into the wheel strut DO NOT tighten into the recess cut into the wheel strut.  The Option B wheel has the cutouts which do line up with the grub screws.

So, "they" sell these wheels in 2 Options, but for Option A they simply turn the wheel... with no thought, or care, as to how that wheel will be secured.  Nice.  Idiots.

Anyway, a bit of grinding and all is well.  Idiots.  Here's the landing gear on a 3-way.

[davidk]

The Flaps on the Learjet, 70mm and 50mm, are persnickety.  You cannot just glue the hinges to the flap and to the wing and have everything line up nicely.  I ran into this with the 70mm when I first glued in the hinges and then found the flap would not close completely because the hinge was glued in about .5mm too much or too little.  I got it to close with a lot of sanding.

This time I'm screwing the hinges together (at the hinge point) and then inserting them into the flap and wing.  This way I have latitude in positioning the hinge... moving it tiny bits within it's glue pockets so that the flap closes perfectly on the wing.  Once in place I add drops of CA into the hinges on both sides.

I'm not going to actually use the flaps... yet... there will be no servo... yet... but they will be functional if I want to put them in place.

[Michael]

Good idea.

[davidk]

All done... and for the very first time, setting up 2 EDFs, they fired up... the first time... spinning in the correct direction.  Yikes.  I mean... you get a 50/50 chance and usually a 99% reversed outcome... right?  These are HobbyWing SkyWalker 40A ESCs with a 5A BEC... so I hope the servos and gear won't overwhelm the BEC  .  These ESCs come with an extra single wire plug for Reverse... so I used the 6th port on my AR620 (since I'm not using flaps) and I've got reverse thrust on a switch.  The fans come to a complete stop and then reverse.  A 3300mAh 4S battery balances the jet almost exactly on the battery tray.  Weight without the battery is 1400g, plus the battery at 343g, for a total of 1743g.  The 50mm 4S X-Fly EDFs put out 1800g thrust together and so we get a 1:1 Thrust Ratio.  All should be good for take-off and flight.  An interesting and fun downsizing project.

[msatin]

Wow. What a beauty!
Great color scheme