Nomadic - Sport Scale Foam Build Thread (GAF Nomad)

[Erasmus80]

I've started working on a clean-sheet foamy that will look a bit like the GAF N.22 Nomad.

I'm working from a GA drawing

• SIZE: My first decision is to make the cabin height 15 cm and let all the other dimensions and parameters derive from that. I'm anticipating a wingspan of about 1.5 to two meters and will be rounding dimensions to make measuring and cutting foam easy.
• SURFACES: I'll use a FliteTest-style folded wing section, looking to the FT Legacy v2 for inspiration, and slinging the nacelles below the wing. Simple flaperons using radio mixing. The full flying horizontal stab is TBD.
• SYSTEMS: Spektrum radio with AS3X. SAFE is TBD. I'm considering 3S power trains with lower pitch props (climb over speed).
• CONSTRUCTION: I'll be avoiding compound curvatures and retractable landing gear. Since I fly off a grass strip, I may leave off the UC completely, so it looks better in the air. Markings TBD.
• DESIGN: I'm planning to draw/build the fuselage in three sections: nose, cabin, tail joined by a standardized interface. My first prototype will be way-stand-off scale. Later, I can make new nose and tail sections that are "more scale".
• PLANS: I will make dimensioned drawings of the various parts available.

 

[Erasmus80]

Forward fuselage structure looks OK.

I still need to make clean drawings of the facetted "Fore Top" and "Main Top". There are many construction lines on the sketches.

The seams are finished with white Gaffer's Tape.

 

[Erasmus80]

More Forward Fuselage views after installing the ceiling portion.

 

[Erasmus80]

I drew and built the aft fuselage and vertical tail. The tail is pretty beefy as it must support the all-flying elevator. I'll cut the rudder free once I work out the elevator. I may cover the tail before flight to relieve the "K'fminess" (steps).

 

[Erasmus80]

I'm still rigging the tail feathers. The horizontal stab is good. I'll be hanging the rudder in the next day or two.

I used some vinal to smooth the stab leading edge. I will smooth out the fin as well.

 

[Erasmus80]

I still need to hang and rig the rudder, but I wanted to rough out the mid-fuselage to get a feel for size. The overall length will be about 40 inches.

I'm beginning to think about whether to add landing gear or plan on hand launches and belly landings. Near scale wheels would be 45mm diameter. That is a bit on the small side for a grass field.

I'm reserving the radome as a weight pocket.

I also attach photos showing my current choice for livery.

 

[Erasmus80]

WING: I used my FT Wing Worksheet to calculate the first draft of the wing and cut a short test section. I made a saddle pocket in the center fuselage and did a trial fit. I'll be adding a doubler to the interior fuselage to spread the wing loads; and, reworking the piece I cut from the fuselage to cover the wing pocket.

RUDDER: I got some new CA as my old bottle had solidified. So, I will soon hang and rig the rudder.

FUSELAGE JOIN: After rigging the rudder, I'll close the aft fuselage and form the aft fuselage interface with the midships fuselage.

 

[Scotto]

That is looking good. Nice work. Your worksheet looks very helpful too.

 

[Erasmus80]

Thanks! Here's a zipped copy of the Excel. Stick to changing the shaded cells only.
There are diagrams on the second tab. Any units will work, just be consistent throughout. I use CM for my usual work.
I usually leave the orange cells alone. They are currently set to the values used in the FT legacy V2 but you can move the spar fore and aft if you wish.
The print range is set up to give you a sheet you can take to the worktable.

 

[Erasmus80]

Tail: I finished rigging the Rudder linkage. I'll be closing the tail tomorrow.

MidFuse: I dry fit the stub text wing. I need to deepen the pocket about 5mm to bring the top of the wing flush with the fuselage top. I will be turning my attention to the lower stub wing and the main wheel covers/pods.

Wings: I'll begin planning the nacelle soon and install one upon the test wing.

 

[Erasmus80]

I decided to sketch out and build a test nacelle.

Here it is on the test stub wing section.

I will run the wires up the leading-edge cell and not weaken the spar with penetrations.

The last photo shows the Nomadic fuselage against the one-half size test article fuselage for the Farman F.60 Goliath I want to build using 10mm foam sheet.

The 3-part fuselage I'm testing in the Nomadic is to prepare for the Goliath. I want to keep the biplane wings and mid-fuselage together and remove the nose and tail sections, so it fits for transport.

I also appended a 3V of Goliath.

 

[Erasmus80]

I returned to the aft fuselage. I closed the bottom and set up the interface with the mid-fuselage. After joining, I used a layer of Gaffer's Tape to clean up the joint for marking the fuselage.

Now, I'm figuring out the lower stub wing that carries the main landing gear. Once that is done, I will set up the nose gear, completing the undercarriage.

Then, I think, I will use some colored packing tape to make preliminary markings on the fuselage.

 

[Erasmus80]

Much work is going on, just not against the Nomadic.
I now have a Cricut Maker 3 and have been playing at making my own markings.
But I have been working on the Main Undercarriage.
I sandwiched a piece of plywood between foam sections and mounted the bent wires to it.
I'm considering making the upper and lower sections of the pod in profile. This would reduce cross-section drag and effectively increase the lift at positive angles of attack.

 

[Erasmus80]

I settled down and finished out the mid-fuselage, building a battery and avionics shelf, and fabricating a trailing nose geal. I decided to set it up like the FT Guinea Pig.

Time to turn to the wing and nacelles.

 

[Erasmus80]

Fabricated the wing (53.5 inches 138 cm) in one piece.
There were some tense moments with the hot glue.

Now, I'll build and mount the two nacelles.

 

[Erasmus80]

I performed a simple set of drop tests on the fuselage--from about 25 cm-- to simulate less-than-perfect landings and discovered a weakness in the fore-aft fuselage interface. The foam board I used for the interface turned out to be a bit brittle and some cracks developed after 8-10 tail-down drops.

I cut the interface out and replaced it with two 4 cm thick EPS foam blocks shaped to fit the interior fuselage across the top and bottom. The added toughness of the EPS passed further drop tests.

Completed and attached the nacelles. I will be making and attaching the "firewalls" this week.

I'm turning my attention to the systems.