Old Fogey Build From Coroplast and EPS Foam

These are the lst recorded thoughts of the Coroplast Fogey ithe controls froze at half throttle as you can here in the video

And wow! Hey! What's this thing suddenly coming towards me very fast? Very very fast. So big and flat and round, it needs a big wide sounding name like ... ow ... ound ... round ... ground! That's it! That's a good name - ground!

I wonder if it will be friends with me?

 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 :(

Here is a video which is pretty funny showing flying my Fogey using the bad method. Seemed to lose all control not sure why. Airframe held up well given the speed it hit the carpark.

A new arival 50% Fogey

AUW 120 grams to heavy at the moment. Getting lighter RX and battery want to get her down to 100 Grams

2900kv C10 motor with a 4.1 X 4,1 draws 5.4 Amps on the test rig for  123 Grams of thrust

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

Looking at building the Old Fogey in alternate materials. Corroplast and extruded Polystyrene. The Polystyrene claims to have a density of 30Kgs/M³, however when weighed it seems to be more dense than that about 34 Kgs/M³

The polystyrene is 25mm thick and at this thicknes weighs 8.75 Grams/dm² versus 4.89 Grams/dm² for 4mm Coroplast.

I found a 2400 X 900 X 25 sheet for NZ$25 here in Christchurch, so here in NZ its a lot chaper than foam board area for area.

I would very much appreciate some feedback on the following data

Fogey Calcs  Fogey on my blog

Coroplast is very tough and pretty light, and stiff.  That said you need two layers to make a wing like these below. For tails planes its hard to beat it seems.

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.

Fitted a 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.

The motor prop maps as follows.

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.

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

 

 

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

 

First use a Pritstick 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 reinforcing 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 front bulk head.  

This piece makes the whole fuse pretty stiff torsionally along its length. Th nice feature of Coroplast 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

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

Tips temporarily secured with packing tape for her first photo shoot  

She's a bit shy and isn't showing us her tail yet :)

 

 

 

My glueless Coroplast and  25mm thick extruded Polystyrene foam construction using high strength double sided tape and Bamboo squewers

 

First use a Pritstick 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.

My glueless Coroplast and  25mm thick extruded Polystyrene foam construction using high strength double sided tape and Bamboo squewers

 

First use a Pritstick 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 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

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