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14 Old Fogey in Coroplast

24gram motors, coroflute, coroplast, Corriboard, old foggy, scratch build, signboard, slow flyer Commenti disabilitati su Old Fogey in Coroplast Old Fogey in Coroplast  

Some tail heavy flying quite a hairy flight the CG was set as specified on the plans. The next flight was much better with the CG set at the wing leading edge unfortunately no video from that flight the camera went missing near the end of the session in the grass somewhere :(

New Indoor 50% Fogey

This video shows piloting using the bad method. The Coroplast held up well (which is why I love it so) with the pretty hard impact failed on the foam to Coroplast interfaces which it what I hoped would happen when I flew it into the ground at mach 1

 Its all fixed now and ready for a calmer day as I was una ble to figth the wind, she just climbed with every gust of our patented New Zealand summer wind

Testing today I found I don't have enough thrust to roll on our course grass at the field.Hand launching in our typically wind weather this time of year she flew but had very little power in reserve.

More power :0

Turnigy L2210 250 Watt with an APC 8 X 4 prop which seemed like the sweet spot. I am re-using a  Turnigy dlux 30A ESC nice smooth controller.

Turnigy L2210-1650 Bell Style Motor
Kv1650 rpm/vVoltage:7.4~11.1v (2~3s)No load Current: 1.3AMax Current: 22AMax Power: 250W

Shaft Size : 3mm

Shaft Length: 28mm

Dimension: 28mm x 17mm

Weight: 50g

The motor prop maps as follows.

Current        Power               Thrust
5A                 57 Watts            300 Grams
10A               114 Watts          547 Grams
16A               172 Watts          730 Grams
28A               276 Watts          1020 Grams   Over current by 6 amps so no full throttle.

Should be able to fly level at 10 amps or less will be running a 1000mAh 3C

Capacity: 1000mAh
Voltage: 3S1P / 3 Cell / 11.1V
Discharge: 35C Constant / 45C Burst
Weight: 92g (including wire, plug & case)
Dimensions: 76x35x17mm
Balance Plug: JST-XH
Discharge Plug: XT60

The Turnigy L2210 1650kv should solve the problem for another 26 Grams well forward, and I get double the thrust.  I still needed to move the GC  forward with the 24 Gram so the bigger 50 Gram motor solves that  without adding ballast.
Hextronic 24 Gram 1700kv not enough grunt on test today, won't roll on my flying field.
 Servos mounted externally 
 Underside wing detail
 Foam joints to set tip angle whole wing weighs 215 Grams
 center section is 500 mm tips as the plan
 Wing detail braced front and rear with Carbon tubes 16 grams
 HK  i86 gyro board
 I put a hatch over the empty chamber in the nose as the CG is stubbornly to far back  

Progressing mounted the servos on the outside so they are accessible. Now with a yellow rail fin with Bamboo spars, still nice and light.

Motor mounted and made a hatch over foam nose structure for the RX and any other bits. The ESC will be on the bulkhead in the air flow 

The 610mAh battery is mounted well forward  with Velcro to get the CG forward, the CG seem stubbornly  to far aft will probably need some balance or a 1000mAh 3C to balance her out.

My glue less Coroplast and  25mm thick extruded Polystyrene foam construction using high strength double sided tape and Bamboo skewers

Currently the air frame weighs 376 Grams bare, not servos, radio, motor or battery. 

First use a Pritt Stick to fix the plans to the inside and cut round with a sharp knife. I glued along the lines on the plan only so I could get the paper off.

I used the blunt end of my steel rule to crease the flutes where all bend lines are on the plan
Then I removed the plan paper before the glue was fully dry which makes it easier to get off.

This is the outside surface
Make a renforceing foam core to fit inside the tail section so you don't have to glue the corners, used double sided tape on 3 sides of the foam core.
Looking aft from the nose and top view with sides folded up

Adding the fron bulk head.  This peice makes the whole fuse pretty stiff torsionally along its length. Th nice feature of Coro and double sided tape is it fails at the tape joint in a crash.
Front bulkhead in position at right angles and flush with the ben of the bottom section. The bulkhead is 100 mm high and in my case 64mm wide 

Note the coroplast want to bend along the middle of a flute so the width you get will corespond to the pitch of the flutes in the Coroplast used.

Front bulkhead with a line at 55 mm from the bottom
From the top
Cut a 55mm piece of foam for behind the screen upto the leading edge
55 X 64 mm
Fixed and chamfered to accept the wing section

Now an 80mm piece for the motor mount. This will be re-enforced further with wood for the motor fixings, and may be the only glued part on the fuselage
I mounted the 80mm section flush with the fron of the topand pegged it with Bamboo. This whole structure add lots of strength to the structure, for very little weight
On the scales
The whole fuselage weighs 115 grams around 15 grams lighter than in the calcs sheet  predicted.

Tail fin cut to the pattern and rudder hinge crease made, no hinge required

Added a 40 mm flat for inside the foam in the tail. The fin has a couple of Bamboo skewers up it for stiffness :)

Foam center block on wing center section. I rationalized the center span to 500mm as it turned out to be some odd number of mm being 18 inches and I am building in Napoleon units

Wing mounted on fuse

Made two 32mm wing sections in foam for the ends of the mid span.
Two sections cut, next time I will cut the profile as one piece then half it :)

Wing profile cut into foam

Wing tips temporarily secured with packing tape for her first photo shoot  
She's a bit shy and isn't showing us her tail yet :)

Like the colour of her dress myself

New Yellow Boat 3 Jet pump

Yellow Boat Maiden

First Yellow Boat failures ESC's died in both boats  very high ambient today over 31°C , at the lake, burned out FET's after all the surfing at Sumner I'm surprised after all the reliable running, still we live and learn air cooled in a closed space like the hull was a bit too good to be true.

Fitted 50 Amp water cooled ESC, which is a marinized aero ESC to Henry's boat, as the HK 50A boat ESC's don't seem that great, lots of motor noise and heating, regardless of settings it seems.

Replaced faulty servo with metal gear type
New improvedWater cooled ESC
Water cooling for motor
Water cooling pump

Thrust vectoring modification

Thrust vectoring in action

Thrust vectoring trim tab

Archimedes screw type pump and cooling system for motor.

 Flexible coupling for thrust vectoring servo push rod.

ESC installed aft as the boat trims very bows down note the water cooling, water is pumped and scooped (when moving) from under the boat, and flows through the motor then the ESC and out of the transom so you can see that it is working.

Cooling pump switch, always turn on before launch, it takes a while to prime usually after a bit of forward motion you should see a flow from the outlet. Forward motion will also generate flow but the pump will stop over heating when you stop so you can stop and start as much as you like.
Radio is mounted to avoid water. Both servos are Turnigy 180 degree metal gear type

New Parts

H-KING 50A Fixed Wing Brushless Speed Controller
Turnigy TGY-R5180MG 180 Degree Metal Gear Analog Servo
Amp rating: 50A
Burst Rate (15sec): 55ABEC Current: 2A, 5V (Linear)
Voltage: (2-4 cell Lipo)
I added two Aluminium cooling tubes boned to its heat sink

Weight: 12g
Size: 23.2mmx12.0mmx21.6mm
Torque: (6.0v)
Speed: 0.12sec/60deg (4.8v) - 0.10 sec/60deg (6.0v)
Voltage: 4.8-6.0vType: Analog MicroGear Train: Metal
Ball Bearing: NoLead Length: 180mm
Plug: JR/Futaba

The water pump showing the motor out on an old servo left, and the intake scoop, you can see the end of the screw

The pump used an ancient Greek idea the Archimedes' screw

This is the screw I used its for GIB board 
Principal of operation

The hull is 4 inches longer than Yellow Boat 1 the keel is fiberglass and epoxy as are the chines, everywhere else its hot glue. Much cleaner hull then the earlier boats but still a bit ugly.
These hulls are tough as, run them into rocks do what you like they just flex. I suppose they would fail at the seams when they do, that's why I glassed in the keel.The hull is all one piece of Coroplast split in the front sections and glued. I scored the folds with a ball point pen so they bend correctly, getting better with the material now.

The ride plate is glassed in on the inside so its really stiff, as the pump is all outboard I have recessed the transom to hide it away a bit. Its a big jet unit.

Room for 2 X 11.1V 2200mAh 20C batteries in parallel should deliver up to 80 + Amps
The cooling system is here

Turnigy 450 H2218 Brushless outrunner 2100KV with water cooling added, big bore pipes just because that the brass I had in stock. 

Model: 2218 
Turns: 6
Cells: 2~4S
Kv: 2100rpm/V
No load Current: 1.9A/10V
Max power: 500W
Weight: 67g
Shaft diameter: 3.17mm
Dimensions: 27.2 x 36.5mm
Recomended ESC: 2~4S/50A

Dragster exhausts :) for the cooling water I have fashioned a pump from some old junk which can bee seen here

Hobbyking SS Series 90-100A ESC with a water cooling plate added its an overrated ESC so should do the job easy. Will need a BEC I have a 5A in stock also.

Weight: 85g
Size: 70x50x13mm
Cells: 2-7S Li Po 
Max Current: 90A [over 70A use 6S only]
Burst : 100A

A real yellow boat



coroflute, coroplast, Corriboard, scratch build Commenti disabilitati su SNAP 

Ding Bat Remnants

Yellow Plane 1

Yellow Plane 2 Near Completion

coroflute, coroplast, Corriboard, FPV, scratch built, twinboard Commenti disabilitati su Yellow Plane 2 Near Completion 

Yellow Plane 2 Near Completion  

Wing Loading         15 oz/ft² 
Motor Power           410 W
Power/Mass            267 Watts/Kg

Fuselage Mass  1040 mm
Wing Span          1200 mm
Wing Chord          280 mm
Take off Mass   1536 Grams

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