Building the Guillow's DC-3 (35.5" span, now 38") with RC /BL motor conversion

[Frank v B]

Next Project is the Guillow's DC-3.  Bought the kit at the London Swap meet two years ago for $20.00.

The DC-3 (35.5" span) is much larger than the B-25 (26.5" span) so the motors will be E-Flite 280's versus the 180's in the B-25.  A 280 is rated at 100 watts.  The 180 is 30 watts.

The other changes will include:
- removable one piece wing using a nylon bolt.
- no retracts (sorry Guy).  Just fixed landing gears.
- increase the wing area two ways: increase the span about two inches and increase the chord outboard of the nacelles.  The wingtips, as designed, are quite narrow.  I am doing this not so much to reduce the wing loading but to reduce the twitchiness of a small plane.
- increase the area of the tail feathers a bit (10%) to increase controllability and stability.

This plane was designed as a static model.  It was never designed to fly.  This is why the caution on the design elements.

Frank

[Michael]

You might want to cheat a bit, and move the nacelles slightly out, in order to make room to swing propellers.

[GuyOReilly]

Perhaps consider the additional scale effect of 3-blade propellers.
There should be enough power to compensate for them being slightly less efficient.
Let me know if you need counter rotating props, I can spare 2, and they are 6-inch diameter.
Also, they are black...

[Frank v B]

Thanks for the advice Michael.  I will check the prop diameter range for this motor and look at the full size plans.
Guy, thanks for the prop offer.  To paraphrase Henry Ford's quote "You can have any prop colour as long as it is black".

Michael, I am seriously considering using the same colour pattern as your DC-3.  It could be your personal Mini-Me.
Now Guy is yelling in the background "Buffalo Airways" colours!

Frank

[Frank v B]

Starting the build
- finished the formers.  Cut out all the stringer and keel notches.  They are piled in the top right-hand corner of the green cutting mat.
- glued the center keel parts together.  Will let the joints dry overnight.

F.

[Andy Hoffer]

Starting the build
- finished the formers.  Cut out all the stringer and keel notches.  They are piled in the top right-hand corner of the green cutting mat.
- glued the center keel parts together.  Will let the joints dry overnight.

F.

It's amazing what @Frank v B  can do with a knife and fork!! 

Andy

[Frank v B]

Starting the fuselage.

One half of the fuselage is built flat on the board, then two main keels (top and bottom) are glued in place to keep everything straight.  Then it is removed from the board and the other half of the formers are glued onto the second half to make the round fuselage.  Same as the B-25 and it makes a straight fuselage.

F.

[Frank v B]

Arghhh!  Cutting out the stringer notches in the second set of formers.  Several of the pieces broke and will have to be glued together. 
With a new knife blade too.

F.

[GuyOReilly]

That is what I call Karma...
Guy

Arghhh!  Cutting out the stringer notches in the second set of formers.  Several of the pieces broke and will have to be glued together. 
With a new knife blade too.
F.

[Frank v B]

The formers for the starboard side.

The formers have to be butt-glued so I added glue tabs (photo 3263).  They lined up the formers when clamped (3264).  It allowed me to use wood glue for the main joint and CA for the small sticks to act as pins while the wood glue dries.

The finished front half (photo 3265) and back half (photo 3266).

The small stringers are next.

Frank

[Frank v B]

Sticks, sticks and more sticks.

The fuselage is very round and taking shape.


F.

[Frank v B]

Picked up the two matching ESCs today at John's Hobbies.  10 amp 2-4S house brand from Horizon Hobbies for $20.00 each, new in package.  Great deal.  I already have the two motors (E-Flite 280's).

Now that there is a "stay-at-home" order, I will treat it as a "build-at-home" order.

Frank

[Andy Hoffer]

Dear Cynthia,

I'm not quite sure how to break this to you.  But there's this new government COVID-19 order, y'see?  And @Frank v B is our CFI so he takes this stuff seriously in order to set a good example for the rest of us.  So you're going to be seeing a LOT more of Frank than you normally would.  I mean in the sense of him being around the house a LOT.  If you can just steer clear of the basement, you should be fine.   

Call me if you need help on this. 

Cheers!

Andy

[Frank v B]

Stabilizer

Problem 1: the stab was made up of many small pieces and was to be aerodynamically shaped per the real one.  As designed it is very thick, labour intensive and not very strong.
Solution:    The new design is flat, strong and simple.  Less than half the number of pieces.

Problem 2: this is a static scale plane and was not designed to fly.  To make it flyable, the tail feather area should be increased by about 15% for stability and directional control.
Solution:    The leading edge was moved forward about 3/8 " and each tip was moved out about 3/4".  You can see the LE balsa was moved forward versus the shaded leading edge on the plan.  The trimming will be done after the fuselage is finished to make it fit in the stab slot of the fuselage.

Let dry overnight.

Frank

[sihinch]

Elegant solution Frank, I love it. Just as a matter of interest, have you calculated the new area vs the original? Is it 15% bigger?