1/4 Franklin Eaglet

[ARUP]

Wing sections built inverted on a jig. Nice l-o-n-g scarf joints used to join spars of central portion of wing to outer tapered portion. Compression struts with drag and anti-drag cables added.In lieu of turn buckles the cables were twisted one way or another for proper tension. They all 'sing' like a piano string when plucked. I made sure they had similar tone. Close up of this rigging shown. This is called 'trammeling' a wing. Lithoplate discs were fabricated and pierced for the cables at the proper crossing angle. They keep the cables from chafing. Tapes were added to the ribs so the ribs won't move laterally. Full scale practice stuff.

[ARUP]

Wing tips added to complete basic structure. False spars let into wing for ailerons. Scale ailerons are on diagonals. These were fitted in scale locations then the 'straight' non-scale portions cut away. This method kept everything very true. Aileron horn fabricated from micarta or phenolic sheet. Piano type hinge recesses cut into wing then 1/64" ply let over top of this flush with surface. The ailerons will get cut free after cap stripping done. Servo compartments built. Gussets for strength. The hatch holds the servo.

[lenb]

Michael.
Beautiful work!!
Its a pleasure to see the structure take shape, especially when you know its drawn from a book and scratch built.

Thanks for posting it.

Len

[ARUP]

Thanks, Len! I may not ever fly it but at least can show how it's built. I've only had one airplane in over 40 years not get past the maiden.
Brass tube edge serrated to perform plunge cut duties. Brass tubes with their respective joiner rods epoxied into place while wings on jig. Fore and aft fuselage wing joiner rod pass through lugs fabricated from 1/4" marine ply. Beefy! They look like puzzles. They ain't comin' apart! They were then epoxied into fuselage setting proper incidence angles. There was a lot of 'behind the scenes' measuring.

[ARUP]

Strut attach brackets fabricated from sheet steel and attached to marine ply. These assemblies were then let between the spars. Music wire segments cut and their ends heated cherry red so they could be hammered flat. Their ends were drilled and tapped 4-40.

[ARUP]

Jig and Rig! Similar flattened, drilled but not tapped music wire let into ends of streamlined struts. Epoxy cures while everything jigged in place. Fairing built over fuse at TE. Scale contours.

[ARUP]

You can see wing 'connectors' on rear spar on above 'fairing' pic. There is a similar one on the front spar. The two wings slipped in place and the wing connectors are sheet steel 'tongues' that overlap and drilled so a bolt (acting as an alignment pin) can drop through them. A gap cover over wing center section keeps 'pins' in place. On to the can-of-peas! Don't forget release, either! It is let into pine and surrounded with CF and epoxy.

[JimD]

A scale builder needs to have precise measuring tools...see post #32 bottom left picture! 😊

Love your build pictures Michael...and I feel sure that you will get to fly this beauty!

[Al Clark]

Very nice Michael! Look forward to seeing her fly at NARCA this Fall.

[Dion Dunn]

Oh, it's going to fly alright. I'll put the local peer pressure on too.

[ARUP]

Yes Jim... measure twice then poke 'em in the eye once! Thanks for the kind words, too!

Thanks Al! We'll see. I quit AMA and I don't feel like eating crow just yet. Let me stew for a while. I wish there was another way to have access to flying fields without AMA. The AMA is a secondary insurer and I'd rather pay for my own secondary insurance that really isn't needed because I'm a hard headed badger who can be spiteful sometimes. But, by gawd, I'm up front about it!

Rigging the tail feathers. That's what she said! A bubble level placed out board to insure no twist rigged inadvertently. Cute little cotter pins made for easy take-down and storage.

[ARUP]

141" span of naked glory!

[ARUP]

Access for elevator push rod if ever needed. Plastic tubing and ferrules for pull-pull cable egress. Tiller for pull-pull made and secured in fuselage. Non- scale skid to get tail feathers off the ground. Since we fly in fields that don't have scale sized grasses, except, maybe, at Clover Creek, the skid will elevate the elevators from contact with 'clumps' that might do damage. Compromises must be made. *sigh* The fore end of fuse got some strengthening infill.

[ARUP]

This is the start of the covering process! How can that be, you ask? This little, insignificant appearing aluminum hoop has to be attached to fabric before it goes onto the fuselage. All fuse covering starts here at this 'alpha' point! A grooved form made to properly bend the 'aluminium' tube. A smaller section of tubing fitted in the ends as a connector. Stand-offs built around the wheel for the hoop to attach. The hardwood skids were formed by hot water and a jig. Absolutely... No ammonia! It 'kills' wood! Inserts were fitted to receive bolts to eventually fasten the skids.

[Dion Dunn]

Set it in the front yard today. It will be a nice backdrop.