Multiplex 100" Flamingo glider (1980 vintage) Covid Build #7

[Frank v B]

Bought the partially assembled Multiplex Flamingo glider via Oscar, my enabler on RcCanada.
I have always liked gliders and the price on this was reduced several times.  There were parts missing (canopy, servo tray- cross braces, plans) but the wings, rudder and elevator were built and ready to cover.  The fuse is very nicely made of fibreglass.
It has ailerons, spoilers, rudder and elevator.  No flaps. 

Basic numbers-
- 100.25" span (2.5 meters),
- 3-4 lbs weight depending on ballast.
- first contest flown in 1980.
- kit first released in 1982

It will eventually be powered but will build it in its entirety as a glider and then surgically add a motor (nose or pylon) once I get an idea of the size and weight.  I may toss it as a glider a few times to see how to optimize it.

The building will be done on rainy days and will probably see the sky next year.

Frank

ps: the kit came out 40 years ago!

[Frank v B]

re: my first post "The building will be done on rainy days"

It was raining today so I made the first two moves:
1) elevator linkage: the fuse cannot be finished until the elevator linkage is made and installed.  It is a flying stab so had to fabricate a horn that could move it.  The hinge point is in the middle of the fin with a radiused slot for the travel.  The horn was made out of an old aileron linkage that had to be extended to reach the slot in the fin.  Photo 1
2) Servo tray- keel.  This part was missing.  It gives strength and holds the servos.  I made it out of 1/16" balsa so it was easy to shape then traced the final product onto 1/8" balsa with cross braces that will be fibreglassed to the fuse.  Photo 2.  The clamps hold the cross-braces in place while the 5 minute epoxy dries.

Frank

[Frank v B]

Photo 1- added the hinge point for the flying stab by installing the control horn.  To make up the difference in diameter between the piano wire and the control horn I used 4 pieces of tubing of telescoping diameter (one inside the other), 4 brass washers on the inside of the hollow fin to make up the thickness and and two on the outside to anchor it.  (see brass washer in the middle of the fin).  The rudder is hinged.  In the bottom of the curved slot you can see the gold coloured end of the elevator belcrank.
Photo 2- the rudder removed to show the new rudder post (1/4" thick hard balsa) and the hinge slots.  Yep, five minute epoxy.
Photo 3- the hard balsa servo tray floor glued in place inside the cockpit. Yep, again...five minute epoxy.

Frank

[Frank v B]

Because of today's lockdown announcement I have officially changed the title from "Time Fiiler Project" to "Covid build #7."

The change makes it a daily time filler.   

Frank

[GuyOReilly]

@Frank v B if it is a "flamingo", will it be pink and stand on one leg?
Asking for a friend...  @Andy Hoffer ...
Guy

[Frank v B]

Guy,

It's a Flame 'n Go*.

F.

* that avoids having to deal with the "pink" and "mono-leg" issue.   

[Andy Hoffer]

@Frank v B 's Flame 'n Go should look something like this when completed. The key is steam forming the wings!  Trailing edges are made of 1/64" 3-ply - articulated of course. 

Landing gear schematic is shown below.  Frank's elevator control horn design will "fill the bill".

Andy

[Frank v B]

After the Flamingo anatomy lesson from Andy I will go back to building.

Installed the control horns and servos.

Photo 1- the servos glued in place with the pushrods attached and neutralized. The sideways elevator servo is trapped in balsa on 3 sides.  Will build it up with another layer and place a strap across.  The elevator servo is a Hitec HS225 metal gear.  The rudder is an HS-81.
Photo 2- the tail group with elevator at "neutral"
Photo 3- elevator at full "up"
Photo 4- elevator full "down"

Frank

[GuyOReilly]

Photo 1- the servos glued in place with the pushrods attached and neutralized. The sideways elevator servo is trapped in balsa on 3 sides.  Will build it up with another layer and place a strap across.  The elevator servo is a Hitec HS225 metal gear.  The rudder is an HS-81.

@Frank v B could you please enlighten us with the type or brand of glue used for this application.
What type of "strap" will be used?
  Thank you. 
Guy

[Frank v B]

Guy,

If a picture is worth a thousand words, here is a 3000 word answer to your two questions....

Photo 1- glue *
Photo 2- strap
Photo 3- in case you want to know where the strap came from.... salvaged from damaged transmitters.  You can see two more "straps" in the yellow box.  I un-bent them.
Note: I had no idea what kind of strap until after I read your post.  After starting the hamster wheel in my head and opening up several boxes, the yellow box offered up a treasure trove.


Frank

* first clue should have been "my name is Frank".

[Andy Hoffer]

After the Flamingo anatomy lesson from Andy I will go back to building.

Installed the control horns and servos.

Photo 1- the servos glued in place with the pushrods attached and neutralized. The sideways elevator servo is trapped in balsa on 3 sides.  Will build it up with another layer and place a strap across.  The elevator servo is a Hitec HS225 metal gear.  The rudder is an HS-81.
Photo 2- the tail group with elevator at "neutral"
Photo 3- elevator at full "up"
Photo 4- elevator full "down"

Frank

Hi @Frank v B .  Intriguing build.  I only have a modest knowledge of physics, especially dynamic loading.  Could you help me to understand what situations might arise which would warrant the hold-down strap in addition to the 1500 psi shear strength epoxy  used to glue the servos in place on (trapped in) the 160 psi shear strength, 145 psi Compressive Yield Strength (Perpendicular to Grain) and 1000-1310 psi Compressive Yield Strength (parallel to grain) balsa. 

Your attentive student,

Andy

[Frank v B]

Answer to "Could you help me to understand"....
1) Rob Dickinson's tag quote is "What could possibly go wrong".  Now this can't be the reason.
2) Belt and suspenders by "Joe Overkill" as my wife Cynthia calls me.
3) If a post-crash evaluation determines it to be "Pilot Error", it would not upset me (been there.  Done that lots).  If it were* determined to be "Builder's Error" I would be very upset.

Frank

* Andy, note the use of the subjunctive.  My grade 8 grammar teacher would be proud.

[Andy Hoffer]

Answer
1) Rob Dickinson's tag quote is "What could possibly go wrong".  Now this can't be the reason.
2) Belt and suspenders by "Joe Overkill" as my wife Cynthia calls me.
3) If a post-crash evaluation determines it to be "Pilot Error", it would not upset me (been there.  Done that lots).  If it were* determined to be "Builder's Error" I would be very upset.

Frank

* Andy, note the use of the subjunctive.  My grade 8 grammar teacher would be proud.

Duly noted @Frank v B !  I am similarly proud of you! It's like a breath of fresh air. Bravo!

(Bad grammar drives me wild!) 

Andy

[Frank v B]

The wing

Description of the challenge
This plane has ailerons and spoilers but was designed for the old 90 degree belcrank in the wing and then to the aileron.  The wing servo was installed (Multiplex BB servo with the old AM 3 pin connector).  The previous owner/builder installed the servo but gave up on how to connect it.

Fishing
- Loosened the pushrod housing that was already installed, tied a string of dental floss to it by force-fitting a toothpick in the tube to secure the dental floss and pulled the housing out from the root rib, then used the dental floss to feed in the 3' of servo wiring.
- soldered the servo wires to the wing servo  (photo 1) and soldered a male end to it on the root end (photo 2).
- tested it with a servo tester (see photo 2- still connected)

Photo 2 shows the root connections from the bottom of the wing.  From the bottom of the picture to the top:
- the new servo wired still attached to the servo tester.
- the spoiler activation wire (push-pull).  It is a scissor type spoiler.
- the dihedral brace- solid aluminum gets bolted together inside the fuse.
- the last pin is the piano wire registration pin for the trailing edge- to keep the wing from rotating around the main spar.  (wingeron?  ))

Frank

[Frank v B]

attaching the wings.  "It just ain't fitting" from Gone with the Breezes.  See clip below.

Photo 1 shows the port side of the fuse after the adjustments. 
- Opened up the small hole at the front and made it into a slot so the servo plug could fit through.  It was similar in diameter as the one at the back.
- had to drill a second hole for the spoiler wire.  It missed by about 1/4"

Photo 2- the starboard servo wire has a Multiplex connector (Dean's).  Have to switch it to a JR/Spektrum compatible plug.  Have to make the holes fit as well.

Photo 3- spoiler in closed position.  Yes, it is blurry.

Photo 4- spoiler in open position. Also blurry.

Frank

https://www.youtube.com/watch?v=tIUlx9mMcXs