Mini Staggerwing.

by alibopo | August 24, 2014 | (5) Posted in Projects

Beechcraft Staggerwing from frozen pizza packaging!

 

Wingspan 38 cm/15 inches AUW 75g/2.65ozs

Motor - Turnigy 1400 4500kv with 4x2.5 prop.

Adhesive used throughout was foam-safe CA and kicker.

This plane is made from the foam found in frozen pizza boxes. It’s about 3-4mm thick. The plane is built using Flying Penguin RC’s flatshot Staggerwing plans printed out at 37%. This fitted the longest components onto an A4 sheet, which is the common office paper size in the UK. I believe the US uses ‘Letter’ size paper which is very slightly different so I’m not sure if it will fit at that exact scale.

After printing the plans I made a couple of design decisions and modifications, which I sketched onto the paper before cutting it out.

I ignored all the fuselage cut-outs, and decided to only laminate up the centre 3 layers and omit the two side panels. I kept the rudder and horizontal stabiliser assembly detail, as that seemed a good way fit the tail assembly.

I adjusted the wing chord, making it about 10mm larger, to give me a little more lift. This influenced the fold lines for the front of the wing, bringing the fold strips that make up the wing 'curve' to roughly 10mm each.

I made the aerofoil shaper ribs all the same. I didn’t intend feeding the wing through the fuselage, so having them consistently a little larger and stronger seemed the best idea. The ones on Flying Penguin RC's bottom wing are flatter, to allow the wing to fit through the fuselage slot.

I added about 8mm to the elevator to give it a bit more authority, but left the rudder the same size. I ignored the balanced rudder detail as it’s too fiddly at this scale.

I used the basic dimensions for the wing separators, but modified these to a large panel. Cut to the ‘correct’ shape, these would have almost zero strength in this material.

I made two extra panels, which I fitted alongside the fuselage to offer greater stability and strength for the wing mounting. The servos are just 'push fitted' in the foam.

After folding and assembling the four wing panels, I paired them up and made them into matching dihedral units. The plane has no ailerons, so I needed something to help stabilise it.

I found that for bevels etc. it was much easier just to compress the foam rather than try and cut it. A light rub with the edge of a fingernail was enough shaping to create the dihedral join! The rudder and elevator hinges were bevelled with the same technique.

I test ‘fitted’ the wings to the fuselage, carefully adjusting the wing cut-out on the top of the fuselage for the larger wing chord. Underneath I cut through the fuselage bottom to remove the slot detail and again adjusted the ‘bedding’ of the larger wing.

Once it was all fitting neatly I glued the bottom wing first, then attached the two wing spacers against the fuselage, making sure the bottom wing remained correctly aligned. I then fitted the two outer spacers to the bottom wing, finally I set the top wing onto the four spacers and the single strip of fuselage at the top. I used the original tab system throughout to help locate the wing formers and spacers. It set-up quite nicely and seems rigid enough.

The firewall is a lamination of tongue depressors! I added two additional foam packers either side of the nose, to increase the width of the nose for a good contact with the firewall.

Here's the maiden:

Power comes from 250mah 2S LiPo batteries, which give a flight time of roughly 6 minutes.

The ESC is a HobbyKing 6A /0.5A UBEC

The 2 servos are HobbyKing 2.5g / .17kg / .12sec Micro Servos (Changed to micro molex connectors.)

Reciever - OrangeRx R415 Spektrum DSM2 Compatible 4Ch Micro 2.4Ghz Receiver

UPDATE 28/03/2015 - I've been collecting and updating all my articles, planes and plans on my own website on this page; RCplanes It's still a work in progress, but there's a few extras and beta-stage projects that don't appear here on the Flite Test website yet.

Happy flying, alibopo :)

COMMENTS

Noobi1951 on August 25, 2014
Wow! You have done a great job on one of the most beautiful aircraft. I wonder how it would take to ailerons on top wing using a centrally mounted servo to control both? It seems to fly wonderfully without it, but would add some interesting capabilities. I don't know that I could keep up with something of that size.

Log In to reply
alibopo on August 26, 2014
Thanks! I have to say this though, the start point and inspiration was Flying Penguin RC's very elegant and well thought out flatshot design. I'm sure an aileron servo would go on quite easily, maybe another 4-5g? You might manage to remove the dihedral as well, though I think it probably helps. With a little thought (lighter firewall, less glue, lighter servos, and lighter motor), the wing loading could be reduced some more, which would give slower flight. Also, the plane will fly a bit slower in the right conditions. It was quite gusty on the day of the maiden, so I kept the speed up. Another way to slow the plane would be to 'fudge' the wing dimensions a little more by increasing the chord by maybe another 5mm (already 10mm more). A tiny scaling-up of the tail surfaces would help as well - that scaling-up practice is very common in smaller builds.
Log In to reply
Flying Penguin RC on August 24, 2014
Great job alibopo, Maybe we should design a micro series. 5 stars

Log In to reply
alibopo on August 25, 2014
Thanks, praise indeed from the master! :)
Log In to reply

You need to log-in to comment on articles.


Mini Staggerwing.