Newton Airlines fleet - 6 months in

Suddenly there are 10 planes vying for space in the hangar (hanging on the wall that is) so I thought it might be time to look back and review the fleet and my timeline of RC flight.

I have always been intrigued by foils. I have been mucking around with kites, sails and fins for as long as I can remember. Seeing what Ed from Experimental Airlines (EA) could produce with foam board, packing tape and hot glue was the inspiration that got me into this hobby so I started with one of his unique designs.


Ansley Peace Drone (APD)


1.5m (60") Quill foamboard wing
750mm (30") depron canard and fuselage
Elevons

This is the very first airframe I built before flying anything at all. It's a canard pusher plane which means the little wing is at the front and the motor is mounted at the rear. The only control surfaces are combined elevator and ailerons or elevons, requiring a programable transmitter.

The APD interested me because Ed designed it to carry a GoPro in the nose. I didn't complete this plane but it taught me the essential EA style building skills.


Photon motor glider


1.5m (60") Quill foamboard wing and fuselage
Depron tail
Ailerons, elevator, rudder
Turnigy 2826/6 2200kV motor with 6x4" prop

900g flying weight

2200mAh 3S battery

I thought I should learn to fly on a more conventional plane with elevator, rudder, ailerons and motor at the front so the APD main wing was reused as the Photon wing.

Timelapse Photon fuselage and tail build


This was the very first RC plane I flew, no experience at all, no friends who flew RC, not even simulator time. I had read a lot and watched videos, but in hindsight I was making my life difficult trying to build and learn to fly my first plane with no help and no experience. But lots of valuable lessons were learned very quickly.

On the maiden flight I did succeed in getting off the ground and flying around a little bit but nosed in after a few minutes - no idea why. On the second flight I launched, flew around (occasionally in control) and glided down for a soft landing when the motor stopped making a noise.

Lesson learned - balance the prop and Locktite the motor mounting screws in.

Photon second flight

Within a few flights I realised that this plane was not the best trainer for a complete beginner. I'd be flying OK then lose orientation, panic and crash, requiring another nose rebuild, so I decided to transform the Photon into another of Ed's designs, the more docile Axon trainer.


Axon pusher prop trainer


Reused wing and tail from Photon
Ailerons, elevator, rudder
Turnigy 2826/6 2200kV motor with 6x4" prop
950g flying weight
2200mAh 3S battery

The great feature of the Axon is that the motor and prop are behind the wing and the nose just holds the battery. As you can see in the maiden video a crunched nose doesn't mean the end of the flying session.

I also added some dihedral to the wing tips which means the plane is self levelling to some extent. The high wing and pusher prop setup make the Axon a much better trainer.

Axon trainer maiden

Success! This plane taught me to fly. No turning back now.


Mosquito


750mm (30") wingspan
400g flying weight
500mAh 2S battery
Ailerons, elevator
Hextronic 24g motor with 8x4" prop

Reusing the APD 30" canard wing section I made up this small and lightweight plane with an arrow shaft as the fuselage. 24g Hextronic motor, ailerons and elevator.

The mosquito was fun but a bit frantic. It was too manoeuvrable and nimble for my flying skills at that stage. I had lots of prop breaking crashes and found it very difficult to keep up in the air. A design to revisit in the future.


Old Fogey

The chaps at Flite Test (FT) designed this slow flying almost comical looking plane and, as with all their designs, provided plans online.

I set about making one from locally available Quill foam board, 24g motor and the same electronics as FT.

It just didn't want to fly, couldn't stay airborne for more than a few meters with the tiny 24g motor and 2S battery. With a more powerful 2826/6 2200kV motor it took off but was uncontrollable.

Turns out the Adams foam board used by FT is half the weight (and 1/10th the price) of Quill. Unfortunately Adams board (also called Dollar Tree foam board) is not available here.

Even drastic weight saving measures, like cutting holes everywhere, weren't enough to get the Old Fogey working well. Most of my problem was reluctance to weight up the nose enough for balance. I'm sure I can get the Old Fogey flying with the right combo of motor and weight balance but for now it is just a display plane. Another project to revisit when time permits. I'll make one from depron eventually and all will be good.


Foamboard in Australia

This triggered an exhaustive investigation into foam board in Australia. I found that all paper-covered board available here was way heavier than Adams and up to 10 times the price. Here's my article on Flite Test

Uncovered 6mm Depron from tradewarehouse.com.au turned out to be the best locally available building material. It's even lighter than Adams foam board and the one of the cheapest options when bought in bulk, working out at $5.30 per equivalent 70x50cm board. The bulk box contains 20 double sized 100cm x 70cm boards and costs $212 delivered.


Bixler 2 motor glider

1.5m wingspan
Ailerons, flaps, elevator, rudder
EPO foam construction
850g flying weight
2200mAh 3S battery

This was my first shop-bought plane and what a revelation it was. I'd advise anyone starting out to buy one of these and the learning experience will be much easier and quicker.

$80 from HobbyKing with motor and servos installed but you need to add ESC, battery and receiver (and flap servos if you want).

It comes with separate ailerons and flaps but no flap servos installed. I added them because I wanted to play with the full house of control surfaces. However the flaps are not necessary for normal flying, might be useful for carrying heavy loads but I think it's better to join the flaps and ailerons to make them almost full span, better for aerobatics.

The Bixler is perfect for carrying a camera and very popular as an FPV (First Person View) platform. Haven't tried FPV yet, another future project. It's a wonderful motor glider to fly, very smooth and stable, can hold up to many crashes, easy to repair and spare parts are very cheap.

Lessons learned - Tighten the prop retaining collet hard. Launching can be tricky, need to give it a decent throw with 3/4 revs and pull back on the elevator stick straight away. The high mounted and down angled pusher motor tends to drive the plane down in to the ground on launch.

Bixler 2 maiden flight - Bixler tail cam


In those early weeks there didn't seem to be many calm windless days, which are essential for learning. There's the biggest tip for learning…wait for a calm day. Wind is your enemy when learning, it's so much easier when your plane isn't speeding off down wind with every mistake.

I decided to use the wind and investigate slope soaring. We have plenty of suitable slopes around Geelong and plenty of wind. The idea of not having to worry about motors, ESCs and props also appealed to me.


Yellow Depron Sloper

1.2m wingspan
130mm (5") chord + 30mm (1.25") flaperons
420g flying weight
500mAh 2S battery
Flaperons, elevator

This TLAR design plane (That Looks About Right) uses a 7.5mm carbon fibre arrow shaft from nose to tail. The 5" chord Armin wing has some dihedral built in which makes the glider easier to fly. To some extent it self corrects the side to side roll. 5mm CF spars fit into a bent aluminium tube to set the dihedral angle.

I was amazed the first time I threw it off a slope, it actually worked. Without really knowing what I was doing I could make it hover out in front. Eventually I learned to fly along the slope but in strong winds I often lost control to see it flying away over my head. However this plane did a lot to train my fingers on the sticks. A great little glider that is still flying today.

Lessons leaned - Slope soaring is great fun. Need to keep it out front in strong wind.

Yellow sloper maiden - Yellow sloper onboard video


Synapse flying wing sloper

1.3m (48") wingspan (measured straight across)
Made from 2 x 700mm, 7" chord Armin sections
7" chord with 2" elevons (10" swept chord)
350g flying weight plus 50 to 150g ballast
4xAAA NiMH battery

Next in the line up was another EA design.
The Synapse was designed as a flying wing with  a fuselage pod holding the motor and battery, but I wanted to try it as a pure wing sloper.

This one is so easy and quick to build, all done in a day. Flying wings are almost indestructible and even after many hard landings this one is still flying today.

This glider prompted me to investigate the many nearby coastal dunes and introduced me to proper slope soaring, what a buzz. Slope soaring is now, by a long way, my favourite form of RC flight.
Can't beat the feeling of climbing to the top of the dune, feeling the breeze straight in your face and seeing the wide expanse of deserted beach below.

Lessons learned - Coastal dune slope soaring is my favourite pastime. More weight is required as wind strength increases. Coastal dune scrub is almost impenetrable.

Synapse sloper maiden - Synapse in 15kn


VERSUS Discus Launch Glider (DLG)

1.5m wingspan
300g flying weight
300mAh 2S battery
Flaperons, elevator, rudder

After watching the DLG episode of Flite Test I had to have one. DLGs are ultralight and highly refined thermal gliders that you launch using a discus style spinning launch.

The VERSUS is probably the cheapest entry level DLG available, costing around $200 for the kit from Hobby King. Four high quality micro servos, small receiver and battery are required so final cost is closer to $300. Competition level DLGs cost 2 to 3 times more but the VERSUS is fine for me.

Here is my detailed video and photo log of the build.

I love flying this DLG although early hard landings have led to a few too many repair sessions. A bad launching technique can play havoc with dodgy shoulders, but I'm improving. Decent DLGers can launch to 60m while I'm currently only getting up to 40m.

If there are no thermals or lift around flights last for 30 or 40 sec. But when you find some rising air the thrills begin and flight times can extend to minutes. There are lots of new skills to learn with launching, thermal hunting and DLG catching so I'm sure I'll be DLGing for years to come. This my plane of choice for warm calm days.

Lessons learned - Don't drop the transmitter while doing the discus launch spin, use a wrist strap. Throw with your body not your just arm.

VERSUS DLG maiden - First thermal - Catch and throw


Le Fish aerobatic slope soarer

1.5m wingspan symmetrical airfoil
Laminate covered EPP foam
Flaperons, elevator, rudder
600g flying weight
500mAh 3S battery

The next slope soarer purchase was inspired by Steve Lange and his Le Fish performing beautiful and mind blowing manoeuvres on the slope. In 2005 Steve designed this glider to perform unlimited VTPR aerobatics. (VTPR - French for Aerobatics close to the ground)

Le Fish is an EPP foam, laminate covered sloper that is designed to fly upside down, sideways, perform loops and rolls and whatever else the pilot is up for.

Here's my build video and photo log for Le Fish. This kit came from Leading Edge Gliders for US$140 plus about $50 freight.

The build taught me lots of new techniques, like foam fuselage shaping, laminate covering and deciding how to lay out the electrics. There are no set instructions and many different configurations.

Flying slope aerobatics takes a lot of practice and glider trimming but it's all worth it. The shape and height of your slope dictates what style of aerobatics is possible. A steep cliff is needed for true VTPR style flying, unlike our gentle low dunes.

Lessons learned - Aerobatics is not easy but great fun learning. You will crash often but these EPP gliders are very tough.

Le Fish maiden - Getting better - Le Carnage


Ultralight Le Fish

1.5m wingspan symmetrical airfoil
Laminate covered EPP foam
Flaperons, elevator, rudder
450g flying weight
500mAh 3S battery

That hard crash in "Le Carnage" prompted me to order 2 spare Le Fish short kits from Flying Foam. I didn't think my first Le Fish would survive my aerobatics learning process.

Turns out I was wrong, it's still going well and not looking like falling apart any time soon.

With one of the kits I decided to build an ultralight Le Fish. Smaller lighter servos and less reinforcing spars save quite a lot of weight and make for a wonderful floaty sloper. It feels quite delicate but less weight means less momentum in the crashes, and I tend to only use this one in lighter winds.

The ULF acts like it's on an elastic sky hook, recovering instantly from stalls and mistakes, and is so responsive it's an absolute delight. At this stage I have only had a few sessions but can't wait for more.

Ultralight Le Fish maiden

Lesson learned - Lighter is better. Le Fish is awesome.


Bixler 2 as a slope soarer

As my sloping skills improved I was keen to try other planes on the dunes.

On one light wind day when the ULF was struggling to stay up I decided to give the Bixler a throw. What an eye opener, very smooth and stable flying in the light lift along the ridge and with the security of the motor for extra light patches.

As a pure sloper when the wind gets around 10kn it is wonderful, not aerobatic but a relaxing cruiser. I guess the flat bottomed wings produce more lift than the symmetrical Le Fish wings.

Bixler 2 sloping


Motorised Synapse wing

Turnigy 2826/6 2200kV motor with 6x4" prop
Hextronic 24g motor with 8x4" prop
550 to 600g flying weight
1300mAh 3S battery

The time had come to revisit old designs and see what some tweaks could achieve.

I decided to try a motor on the Synapse as Ed originally intended and the result was excellent. The Synapse, if the weight is kept light, makes a really nice slow and steady flyer.

With the extra weight of motor and battery it became a much smoother and more controllable slope soarer too.

Motorised Synapse - Slope soaring


2m motor glider

2m wingspan
5" chord + 1.5" ailerons
750g flying weight
1300mAh 3S battery
Turnigy 2826/6 2200kV motor with 6x4 prop

I have been hearing so many glowing reviews of the 2m Radian motor glider so I thought I'd try to
make something similar.

Unfortunately this one never lived up to my hopes. It looked great and climbed eagerly into the sky but the glide slope was terrible and directional stability all over the place. It would loop up and down and wobble side to side excessively. Shifting the CG around didn't seem to help much. Taking out the dihedral did smooth it out a bit but didn't improve the glide slope to what I was expecting.

In the end I figured my airfoil shape was too fat. The wing was a 5" chord Armin style construction but I was using 6mm depron, not 5mm Adams foam board, and a 7.5mm spar. With 2 layers of former and the thicker spar mine ended up about 26mm thick compared to Ed's 20mm.

I eventually crunched this plane trying low level inverted flying. Might have been sub consciously deliberate? Anyway I was glad to move on and investigate thinner airfoils suitable for my 6mm depron.


Ansley Peace Drone - revisited


1.5m (60") wing
750mm (30") canard and fuselage
Elevons
Turnigy 2836 1700kV motor with 10x4 prop
950g flying weight
2200mAh 3S battery

I slit open the 2m motor glider wing, ripped out one layer of former then glued it back together.
Cut down to 1.5m it made the APD main wing with a slimmer 20mm thick 5" chord. One of the 25cm offcuts and the original APD canard made up the new 30" canard and the APD was reborn.

This is a real slow and steady cruiser with elevon control only. It's great in a straight line but to turn it needs sufficient speed and height. It looks plain weird in the sky seemingly flying backwards.

As a slope soarer it was not a great success. Motor is required to make the turns but it cruises along the ridge nicely.

Ansley Peace Drone - APD sloping


Orange slim wing

1.2m wing
6.5" chord + 1.5" ailerons
20mm thick
Flaperons, elevator, rudder
Turnigy 2826/6 2200kV motor with 6x4 prop
600g flying weight
1300mAh battery

I made this plane to test the theory that a thinner airfoil is better than one that is too thick.

The slimmer wing works very well with a great glide slope and smooth controllable performance, none of the looping and stalling of the 2m wing. Mild aerobatics like loops and rolls were easy and it could fly inverted with heaps of elevator.

An electrical brown-out brought about the premature demise of this one, maybe due to my dodgy soldering. I have since upgraded to a more powerful soldering iron.

Orange slim wing maiden


Orange slim wing slope soarer

1.2m wing
6.5" chord + 1.5" ailerons
20mm thick
Flaperons, elevator, rudder
450g flying weight
500mAh 3S battery

I rebuilt this one as a sloper, which basically means replacing the crunched motor mount nose with a longer battery-holding nose.

Awesome, it worked very well, nimble, light and easy to fly. Rolls were OK but inverted required heaps of elevator. Loops weren't possible.

Orange slim wing sloper

Next project is to try this glider with a symmetrical wing and Le Fish sized elevator and rudder.

Ultralight 450g Le Fish

While learning to fly my 660g (23oz) Le Fish I crashed often and hard. This prompted me to look for a spare fuselage and wing. Although EPP is very tough and repairable I felt that eventually a new fuselage would be needed. Actually the green Le Fish is still flying perfectly and probably will for years to come.

Flying Foam sells a short kit (just the wings and fuselage) for US$65 plus US$50 freight to Australia. 2 kits will fit into the box for the same postage, so I bought two.

I decided to use one of the kits to build an ultralight as light as possible. It came out at 450g (16oz) with a 500mAh 2S battery and CG balanced, which is fantastic.





The flying experience is remarkable, quite different to the heavier version. It recovers from loops or stalls so easily, seems like it's on an elastic band hooked to the sky. My slope is not very steep so I still have to stay out in front but I can perform more tricks with this sloper and in a wider wind range.

The build was mostly the same as the green Le Fish but with less spars, lighter hardware and servos, lighter rudder and elevator servo forward in the hatch. The wing tips and tail boom feel quite flexy, they're fine in the air but a bit delicate for handling on the ground.

Will they be tough enough? Time will tell. As this Le Fish is much lighter and mainly flown in light winds the landings and crashes are gentler.

First off I gorilla glued the wings together using a 1m long 1mm x 6mm CF ribbon spar. That leaves the outer 25cm of the wings unsparred and quite flexy. There is no trailing edge spar at all.

The wing is covered all over with 1.7mil laminate and another 3mil layer on the D-Box. I decided to try oversized 60mm ailerons hinged with 3mil laminate and they seem to be working really well. I made lightweight control horns from plastic ID card and gorilla glued them in place with another rectangle of ID card for reinforcement.


The Flying Foam fuselage is thinner than the Leading Edge Glider kit and I sanded it down quite a bit further. Interestingly there is a thick half and a thin half. This means you can site all the gear in the thick half.


The rudder and elevator servos are accessible through the hatch and use Gold-n-rod #503 push rods. Aileron servos are just forward of the wing as usual. I used Turnigy 9018MG micros all round and they're working well.

Fuse is covered with 3mil forward of the wing and 1.7mil aft and there is no longeron.












Horizontal stabiliser is conventional, not full flying or mad, and the rudder is as light as possible made from raw uncovered depron. I wasn't tempted to cut swiss holes anywhere, they look good but reduce strength for not much weight saving.

Here's the maiden flight of this amazing ultralight aerobatic slope soarer.

Le Fish aerobatics progress

A few more tweaks.

The new solid 3mm CF elevator axle / spar is working perfectly.

I removed 10g from the nose to move the CG back to 80mm giving much better inverted flight control. Decreased the "normal flight" elevator throw and increased expo for smoother flying. Full throw, about 60º, is still available via the momentary switch.

I tried moving the pushrod down one hole on the elevator control horn to get 90º throw for proper mad flips but the elevator would return fully inverted. Might need to move the control horn back from the pivot axis or try a pulley system.

The vertical stab and rudder CA hinges failed in a nasty upside down crash so I re-glued the join and used clear gaffer tape for the hinges.

Anyway I'm steadily ascending the aerobatics learning curve and having great fun in spectacular locations. Here's some video from 13th beach in a lovely 10kn breeze then some thrilling 20 to 30kn later in the day.

Le Fish build follow up

After 3 hard sessions of flying (and crashing) it's time to assess how my build methods held up, and share some setup tips.

The wind has been 15kn gusting up to to 20kn for every flight. At that wind strength it's easy to lose control of the glider and see it cartwheeling backwards across the top of the slope, but I guess it teaches quick reactions and accelerated learning.

Elevator spar / axle
The 3mm CF tube elevator spar / axle snapped on the first day, a clean break across the fibres, which is very unusual for CF tube. That leads me to think it was a pre-existing weak point. So I replaced it with another 3mm tube. Dremel and knife freed the spar from the elevator planes.

The new spar broke on the second session, but cracked along the fibres this time, from torsion stresses maybe. Conclusion - 3mm CF tube with 0.5mm wall is not strong enough for the job. So for the third spar I glued a 2mm rod inside 3mm tube (until I can source solid 3mm rod) and that seems to be holding up OK, although two elevator planes don't feel as solidly locked to each other as I would like.

Fuselage laminate covering
The light 45um laminate did not bond well to the fuselage and came unstuck right down each side. Might have something to do with the fuselage flexing on impact.

So I tore it all off and recovered the fuse with 75um laminate. This was a bit fiddly with the plane fully assembled. I used 300mm x 50mm strips along the entire top and bottom with lots of tabs cut for the curves, 2 layers built up forward of the wing, single layers above and below the wing and two layers running down to the tail. The result is much stiffer, smoother and better bonded to the foam.

Fuselage cracks
While the fuse was undressed I checked all over for cracks. The nose was split open a little, there was a vertical crack just behind the wing leading edge, and the wing / fuselage join had parted in places. Gorilla glue to the rescue. I also added clear gaffer tape to protect the nose. This stuff is great, very strong and more stretchy and flexible than the coloured cloth tapes.

Loose servo
The elevator servo had broken loose in its hole. Just needed a few drops of CA to fix it back in place.

Transmitter setup
Full throws on the control surfaces are way to much to start with so I dialled in 50% dual rates for everything, 50% expo for rudder and ailerons and 70% expo for elevator.

I still wanted full throws available for attempting mad stunts so programmed the momentary switch to turn off dual rates and expo.

Snap flaps can be switched on, giving about 8% camber (down ailerons) for up elevator and 8% reflex (up ailerons) for down elevator. Apparently that makes loops and turns sharper.

I have full throw flaperons / spoilerons on the throttle stick, called 4D by some folks, for on-demand camber changes. I have only used this for landing so far. The curve for this mix has a 50% dead zone in the centre so I'm less likely to make camber changes accidentally.

I also have 15% and 30% flaperons on the 3 position switch for low lift times.

Centre of Gravity

Doing a loop

Initially I set the CG at about 70mm which is OK for starters but noticed heaps of up elevator was required to fly inverted. This tells me the CG is too far forward, so by removing 10g of nose weight it is back at about 80mm now. That will make the elevator more sensitive so I may need to add more expo to keep it flyable. The next flight will sort that out.

Le Fish maiden

The forecast was for 15kn NW increasing to 30kn mid morning, so I raced out early to the closest NW slope - Pt Henry.

The actual wind direction wasn't great, 45º off the the right, but OK for a first throw.
On the first crash the elevator had inverted and I clumsily cracked the spar / axle twisting it back the right way. The off side of the elevator could almost rotate independently of the controlled side but I decided to press on regardless to a better slope at Clifton Springs. .

In the meantime the wind had increased to 15 to 20kn but from a perfect direction.

Here's the maiden video warts and all. Le Fish flew spectacularly and I even managed a few tentative loops and inversions. Gliding back and forth along the slope was so smooth and controlled. I can only improve from here.

I learned not to take my hand off the elevator stick before trimming for level flight. I reached up to turn on the GoPro and the plane went into a dive and disappeared down the slope. It landed in nasty head height scrub but no damage apart from a few scratches to the pilot.

Dual rates and expo of 50% for everything helped calm the flight down for this first test.

A new stronger elevator spar / axle was fitted afterwards. 3mm CF tube with 2mm rod glued inside this time. Might still need a solid 3mm rod for durability.

Le Fish build

Le Fish is a 60" EPP foam aerobatic slope soarer, designed in 2005 by Californian Steve Lange (slopeaerobatics.com) and sold in kit form by Leading Edge Gliders for US$140 plus US$54 international postage.

The first time I saw video of Le Fish performing crazy stunts I was awestruck. These mad slopers can fly like they are possessed. Have a look at this to see what I mean.

Leading Edge Gliders have changed the design slightly by increasing the wingspan to 66". However the designer recommends sticking to the original 60" for snappier performance and easier transport.

The LEG kit includes foam wing cores, foam fuselage in 2 halves, balsa tail parts, carbon and timber wing spars, carbon longeron (or is it a bottom wing spar?), 2 yellow plastic pushrod with red plastic casings (Gold-n-rod 503) and an accessories pack

The pack contains…
2 x 2mm short wire pushrods (ailerons maybe)
2 x nylon pushrod locks (fit over an L bend)
6 x brass clevis (one of mine is already installed)
4 x short threaded rods (pushrod adjusters)
4 x control horns and bolts
3 x hairy plastic bits (CA hinges for rudder*)
U shaped elevator joiner

* I had no idea what the hairy plastic bits were for until I stumbled across this explanation.




The rest, including covering material and electronics, is up to you to source.

The recommended covering these days is laminating plastic for documents or posters, referred to in the RC world as New Stuff. It's very cheap, tough and comes in a variety of weights. I ordered 10m each of 75um and 45um from www.aussieflight.com.au for $1.00/m. It's applied with a small hobby iron or a normal clothes iron.

For servos I went for 4 Turnigy 380MG micros  for about $15 each. These powerful funky transparent purple servos work well on my KAP rigs. They will be strong enough but I don't know about speed and accuracy yet.

Le Fish has evolved over the last 7 years with a vast variety of weights, materials and layouts. There are no official instructions, the idea is to build for your conditions and desired flying style.

The Le Fish Wiki explains three different build styles.

Traditional - 1kg build using extreme packing tape, strong covering material, multiple carbon and timber stiffening spars and standard sized servos - great for strong winds and durability.

Middle weight - 700g using lighter covering, less spars and smaller servos - a great all rounder.

Feather weight - 500g using depron tails, no longerons, micro servos and the lightest covering - a light wind specialist.

The most common wind strength here is 15kn so middle weight is right for me.

Fuselage shaping

The fuselage comes as two halves with square edges. For looks and performance you need to round off the edges.

EPP is difficult foam to shape being tough and flexible. I tried 80 grit sandpaper but that tore out chunks. Then tried plaster sanding mesh which was much better. You need to go slowly and sand in one direction with long smooth strokes. It's up to you how far to go. Sand away till it looks good is my advice.

Some beads of foam will be pulled out but that can't be avoided and the iron-on laminate covering will smooth out the surface.

I sanded a big chunk out from the wing cutout area but it was easily repaired by glueing in a scrap of foam and sanding flat.

Here I'm sticking the wing cut closed with 5 min epoxy. I suspect it would be better to do this before shaping.

Servos and electronics layout

Next you need to decide where your electronics and servos will sit. This can take a fair bit of thinking time. It's a good idea to read all the Le Fish threads on RCGroups and decide what you want. There are no rules but it's good to keep the weight forward and to make sure everything can move as intended.

I went for a similar layout to the Swiss Fish build with aileron servos just in front of the wing,  rudder servo inside the hatch and elevator servo just behind the wing (for the Mad Stab setup). Mad Stab is when the entire horizontal stabiliser can rotate 90º up and down, allowing for crazy end over end tumbles. 

The carbon longeron runs from the very rear of the fuselage passing under the wing and low enough to leave room for the aileron servo.

A Dremel with the milling bit works well for removing foam but it's tricky to hold a straight line. Take care and go slowly with a firm grip on the Dremel.

I used brown Gorilla Glue (for the first time) to fix the longeron in. Faster drying white Gorilla Glue would be better but it's not sold in Australia for some reason. A scuba weight belt held it all flat while drying.

Gorilla Glue foams up and expands on contact with moisture. Here's a little test to show the foaming.

Top - just after squirting the glue in.

Bottom - after 1 hr.

The groove was painted with water first to accentuate the foaming. There was so much expansion the skewer lifted right out of the groove.

The second groove on the right was left dry and the top half covered with tape. 

Seems there are specific techniques required for successful gorilla glue use. Will I use Epoxy or Gorilla glue?…..not sure yet.

Now for the side hatch and battery / receiver space. The battery will sit in the nose as far forward as possible and the receiver behind that, accessible via the hatch.

I probably have that space and the hatch too big but we shall see. At least I have easy access to everything. 

The rudder servo sits now in the top of that space. I changed my mind about the positioning, hence the filled-in servo hole in this photo. The servo and push rod were originally going to be external but that looked too ugly.

A bamboo skewer was used to poke a hole for the push rod to exit. The hole was enlarged with a drill bit. The red plastic push rod casing was glued in with CA, which takes ages to set on this foam, especially covered with tape.

Actually it took me some time to realise the red tube was the casing and the yellow tube was the push rod (called Gold-N-Rod). I initially thought they were both casings and you had to source your own push rods. Some basic instructions or even a list of the accessories pack contents would have been a big help.

The rudder servo was wrapped in masking tape and glued in with a few drops of CA. I'm thinking more of making it easy to remove rather than fixing it in solidly.

Here are the two halves ready to glue together. I added an extra carbon rod stiffener above the receiver space because the big hatch weakened the nose area. In the Ultralight build no longerons are used at all with the iron-on laminate providing all the strength, but I'm aiming for a sturdier middle weight Le Fish.

After testing the Gorilla Glue on scrap foam I decided to use it for the fuselage. I used a damp sponge to clean and moisten both surfaces. Moisture promotes foaming of Gorilla Glue which helps span any gaps.

I applied a very thin bead of gorilla glue all around one half of the fuse then spread it out with a scrap of depron. I used as little glue as possible to avoid excessive glue expansion and I may have to pull the fuse apart one day.

Weights would distort the fuse while curing so I taped the halves together with electrical tape.

Trimming and gluing the wings

5min epoxy to join the wing spars together using the aluminium joiner.

To reduce the wingspan from 66" to 60" I cut 3" off each tip

and trimmed the excess wing spar at each end

I followed these instructions for gluing in wing spars, using the wing beds lined with baking paper top and bottom to prevent sticking. Squeeze a very thin bead of Goriila Glue into the spar channel after dampening with a wet sponge. Use a dowel to scrape out most of the glue then dampen the spar and push into the channel. 

Cover with baking paper, place the top wing bed on top and weight down to hold it all flat.

It worked very well for the spar with minimal foam extruding out to the top.

Didn't work so well for the wing join. It's strongly glued but I can see too many gaps in that join, more glue required.

Now for the sub trailing edge spars.
I had some 25mm x 0.8mm CF flat laying around so made up a jig for the dremel to rip it into 7mm wide ribbon spars. Hard wood spars are provided in the kit but they add more weight than needed.

Glued a 75cm spar on each wing half and overlapped the join with another 30cm section. 

The overlapping section of ribbon spar was flexible enough to bend over the angle at the join without leaving a gap. Electrical tape wrapped right around the wing held it all in place while curing.

Here you can see the extra spar piece in place covering the wing join.

A sharp knife trimmed off the foamed Gorilla Glue easily

I smoothed out the sub trailing edge with sand paper. Unfortunately this created some black CF dust which stained the adjacent foam.

Wing is getting stiffer now. The covering will make it even stiffer.

Depron tail feathers

I'm replacing the balsa tail feathers and ailerons with 5mm depron to save weight. It seems very fragile but becomes quite tough when covered with laminate.

Used the kit bits as templates for the rudder.

For the full flying stab I used the version in Le Fish plans.

I won't set it up for full Mad Stab 90º throws to start off with, maybe later when I know what I'm doing.. 

The centre section is 6mm balsa, bearing tube is 5mm OD carbon with 3mm ID and spar / axle is 3mm carbon tube.

It's important to have a slop free fit for the bearing. I had to sand down the axle slightly for free rotation so it's as good a fit as possible.

A round file was used to shape a groove in the balsa.  Bearing tube was glued in with epoxy then carefully taped level and square.

A cutting mat with 90º lines is invaluable for this sort of task.

Spar / axle epoxied into grooves cut into the elevator halves (after laminating).

I added small stainless washers either side of the pivot to protect the depron in that area.

Using New Stuff iron-on laminate

The adhesive from this laminate can goo up an iron so I went out and bought the cheapest iron I could find, $24 from The Good Guys. I kept mine on Wool setting which is medium heat.

For this build I used 43um laminate on all surfaces with extra 75um for the wing D-box and hinges.

This is my first attempt at using New Stuff and it can be a little tricky. It's not flexible or stretchy so you need to cut tabs to go around curves. Narrower tabs for small radius curves and wider tabs for gentler curves. Even so don't expect a perfect wrinkle free result. Best to practice on something flat first like the horizontal stab or rudder.

A good tip is to start by tacking it down onto a flat area first then cut the tabs where needed.

The tabs are then folded over and ironed on to the edge and around the other side. Then repeat the process with another piece of laminate for the other side.

The fuselage is the trickiest part to cover due the complex curves. Keep tension on the laminate as you iron it down to minimise the wrinkles.

You will get some wrinkles but don't stress too much about it, the end result will be fine.

Start in the middle of a large flat area and iron outwards...

 then iron each tab over the edge

I felt like I was mucking it up at the time but the end result is much better than I thought.

The wing is easier with less complex curves. I wrapped one big piece around the leading edge and overlapping the sub trailing edge by about 5cm each side.

You can pop any air bubbles with a pin and iron flat.










Here I'm adding the thicker second layer to the D-box (front section from spar on top around to the same spot underneath)

Ailerons are 5cm wide depron with a 45º bevel sanded for the hinge line. Covered with laminate as well.

Left the square trailing edge as is. Apparently it doesn't make any difference.

These light depron bits are sort of treated as consumables to be abused and replaced as needed.

Slot the wing into the fuselage (it won't fit once the 'rons are on)

Attach the ailerons using the heavier 75um laminate to create a hinge. 50mm wide strips are ironed on top and bottom, with the bottom strip adhered right up into the hinge gap.

I used 3 shorter lengths for each side rather than wresting with the full 75cm length strips. Less wrinkles that way.

Gluing the wing and stab on

Now that everything is covered it's time to assemble the beast.

Measure carefully and make marks in at the wing
root leading edge and trailing edge to ensure the wing is centred and square.

Alignment marks help to slide the wing out a little, apply glue then slide it back into position.










You can flex the gap open a bit to squeeze glue in after wiping with a damp sponge to provide some moisture.

Wipe off the excess glue.

I'd rather this join gave way in a bad crash.

Wipe down with the damp sponge again.

Finally, make sure the wing is centred and square to the fuselage once more.

Now for the horizontal stab.

I removed the laminate to allow a strong balsa to foam bond.

 Gorilla Glued the stab on.

The depron stab still seemed too flexible and fragile so I ironed on another layer of 75um laminate.

Held parallel to the wing with electrical tape while curing.

Rudder hinge, that's what those little plastic rectangles are for.

Make sure you look at this info before proceeding. Great explanation and tips.

The top two are inserted into slots cut in the vertical stab and rudder, then a few drops of CA glue added to fix them in place.


The CA wicks into the foam making a very secure bond.

Just make sure you wait for at least 30min before testing it. (Unlike me)

The bottom one inserts into the fuselage when the vertical stab is glued on.

Here I'm marking the hinge slot position.

Gorilla Glue applied and vertical stab taped in place to cure.

Fingers crossed.
Hope it's strong enough and straight and square.

Connecting the control surfaces

Home stretch now.

I cut small pieces of blank credit card to spread the compression load of the control horns. I think stiffer ply would be better but credit card will do for now.

Aileron push rods made from 3mm carbon tube with 2mm threaded wire on the clevis end and L bend with nylon lock on the other end. Glued in with epoxy.

The wire pushrods in the kit were not long enough for servos in the fuselage.

Ailerons connected.












Elevator pushrod with an adjustable clevis on each end.

This setup allows for about 80º up elevator but only 40º down due to the rudder pushrod. A little cutout of the elevator would fix that.

However I'll start with conservative throws on everything.

Rudder plastic pushrod with threaded rod and clevis.

 Le Fish is finished…












Le Fish needs a bit of colour so you can pick the orientation in the air. This is coloured packing tape which can be removed easily and doesn't add much weight and the canopy is black book covering contact.

The 5xAA battery pack put the CG about 50mm too far forward. For stronger winds I could use that battery and add tail weight.

Correct starting CG of 75mm from wing LE worked out by using two 500mAh 3S LiPos and a BEC, which results in a minimum flying weight of 640g (22.5oz)

I'll keep searching for the ideal single battery pack, maybe 5xAAA.

Couldn't resist having a throw in the backyard.

Update 7th Jan 2014: Narrated build video is up now