Chris Van Hoof's Cozy Mk IV

Plan # 219


Chapter 22 - Electrical Installation

Basic VFR.

Now define basic...

More stuff, more wiring and plumbing ... to go, is there an end?

Have a look at the snazzy wingtips that I'm creating, they will house the strobe and the steady lights.

Just does not make sense to have such a clean aeroplane and then hang stuff on the outside :-)

the preparation for the cutting is shown here, lots of head scratching and trepidation.

Here you see the cut out piece on top, a shaped male mould for the lenses and a block of wood that will become the mould for the right hand wingtip.

Just ordinary tools such as saws, files, rasps and sandpaper were used here.

These male mould then received multiple layers of duct tape to the same thickness as the Perspex and polycarbonate sheet that we will use.

This whole lot was put in a box and filled with pour foam, thus producing a female side of the mould.

When the wife was out for the day I put the sheets in the oven and cranked this up to 140 deg C.

This renders the material soft and pliable and (with gloves) you just drape it over the male mould, push the lot into the female and wait for it to cool down.

The multiple varied curves taught me all about patience and perseverance!

So eventually we could use 2 out of 14 attempts, with 2 spare for in case.

Since we now have the lens, it is a matter of getting the shapes to match and then create a lip for the installation. The lens will be held in place with two screws.

And here it is fitted.

Just waiting for the LED bundle of navigation lights and a strobe.

Front - Red And Green LED's are installed in two separate clusters on each side.

Due to their directional nature they had to be angled to spread the light, so it does not photograph too well, you'll only see one or two at a time. Looking at them you do know that they are bright!

The red has the cover installed, while the green has not - all for the purpose of photos ... The standard strobe (in the middle) is described elsewhere on my site.

LED's are installed with silicone in a 1/8" Perspex panel, this allows for easy repairs.

So, with this setup you will need some tail lights.

This was done by chamfering a 25 mm plastic pipe, attach to the bottom of the winglet with 5 min epoxy and 2 x bid, smooth with micro.

This will receive a bundle of bright white LED's.

White tail light assembly, on some sticky stuff to facilitate working.

This photo prior to wiring being done - did I have to mention that ? :-)


Q & A

 Does it look good - it does, to me :-)

How much time for this mod - all in exceeds 150 hrs.

Would I do it again - not really, change it maybe to a bolt-on cover a la Jabiru.

(Which goes to show that any deviation from the standard plan sets you back more than you cater for.)

Because we gained such vast experience with the above, we felt that the "recognition" lights would be easier, and they were, mostly because the don't have compound curves.

Recognition light in strake end. Automotive aftermarket fog light.



Chapter 23 - Engine Installation

And  then my friend Brian Zeederberg  sourced an IO-360 and here it is in the workshop -- man, they have a lot of pieces.

We are learning all about aviation motors. At this stage I am not clever yet, but I'm learning fast ... what I have noticed is that they talk more bull about motors than about white wine :-) ... and everyone is an expert !

The engine mounting was created by Wayne Estment's "B H Welding" outfit, since I used their facilities for smaller stuff, I can now recommend them ... and they don't charge US Dollars ... that means a saving of 50% to a South African. Mostly due to the cartage and import tax costs.

Gavin Lawson put this all together as per the Lycoming literature and we will soon know how much power it puts out.

Both photos show the completed motor on a special transport stand designed by Gavin Lawson.

All you have to do is: hang the motor on a hoist, remove the stand, bolt the engine mounting on and install the complete caboodle in the plane.

And here it is at home ...

Of course we still will fit the baffles, oil cooler, pipes, wiring and cables, but the end is in sight :-) or is it?


Cowling - How to make your own

Due to the Rand / U$ exchange rate at the time, a ready made cowling was unaffordable, thus we make our own.

Anyway, we then fitted the motor to the firewall and determined the space required, as well as the clearances ... this is one very tightly cowled effort, so watch this space.

Gavin Lawson was talented with the lathe and manufactured a wood crankshaft, which was very useful to determine the exact position of the flywheel, prop extension and to hold the former, as is shown on the photo.


Wrap it up with cling wrap (Saran wrap for the USA folks) and add foam and shape to suit.

Pollyfilla the plug, tape with box tape so that it will release and cover with BID & UNI.

Here Gavin Lawson (L) & Chris van Hoof are working against the clock, the winter sun was warmer than anticipated :-)

Wings removed, ready to turn the plane over, thus you invite your EAA buddies 

and have a lunch, after the turning :-)

We did tell you that the shell of the motor was installed, didn't we?

This photo made us decide to install the "boat tail" 

Gavin Lawson does the final shaping and measuring, before we do the lay-ups.

And the final product, Top is on the LH, bottom on the RH.

Heat shield applied to bottom of cowling


Ram Air for more power - we hope

So, once again we could get on with fitting the motor.

The plan of action is as follows.

Bracket to front and rear of throttle body to eliminate vibration. (rear bracket in position).

Carbon fiber pipe (here shown in blue foam) increasing in size (same as Lyc. part but increase from 45 deg to 180 deg) to get air from throttle body to sump, etc. White foam indicates air filter, just for show and tell.

and this is the foam core, ready for smoothing and covering with carbon fiber. the carbon fiber is not attached to the bracket - it will receive a carbon fiber flange - all manufactured in one piece.

Of course, the alum bracket had to be made 3 times. Because my mother raised a slow child :-)

The inlet on the sump is off center, so we learnt to do this quicker :-)

Here is the freshly made carbon pipe still attached to the Aluminium flange. Foam was made smooth with Polly Filla, a plaster type filler, then sanded smooth (150) and sealed with red candle wax, also the holes, so that no epoxy could get to grips with this. Finally a good rubbing with Run-In-Wax which is a mould release agent. (Smells and feels just like ordinary floor wax). After the lay-ups, it was left to cure 24 Hours at room temp (24C), then i shoved it in the house oven, at 100C for 3 hrs and 120C for another 3 hrs, then i got bored with it and declared it hard, so we'll have to see how it all pans out :-)

The sump drain is rerouted to the side (RH in direction of flight) for access. On the LH side of this photo we will manufacture an air-entry box which will house the air filter.

And the final product, seen from the rear.

Then the exhaust pipes were fitted, I had the local Exhaust Shoppe bend a bunch of 90 deg angles, so that I could cut and tack this lot in place, about 5 hours total time.

Plane is standing upside down :-)


Chapter 24 - Covers & Fairings

leg covers, protect fuselage with tape, install foam, do lay-ups, remove, cut & trim ... that's about it :-)

Gavin Lawson made the plug for the spinner.


Chapter 25 - Finishing

So we started on that filling & sanding thing everyone talks about, well I must be missing something, or maybe Graham Pick did such a superb job with the foam cores that it seems to be very little, bar the odd drip of epoxy ... anyway, it'll probably show once we start with the primer.

The gap on the strake to the wing is one metal blade hacksaw blade wide, so I chamfered the top edges, so that the silicone sealer will have some body to expand.

The rear gap along the main spar is 3mm, same reasoning. Silicone sealer can expand up to 30% of the gap sealed, the one I've got does anyway :-)

This micro, filling, sanding stuff is not too difficult, it is really just a bunch of manual labor.

The sun gets to you, here in Johannesburg, South Africa, so you work best before 10 am and after 4 pm.

Otherwise you work in 30 C ( to 40C ( 95F to 104F).

Anyway it took two weekends to complete the bottom of the LH wing and strake.

I'm getting fit, but not liking it, may just farm this work out ... we'll see.

And don't park your plane under a berry tree ... 

OK I took a decision to have the final sanding done by Arthur Smith.

So that meant that we loaded the whole contraption onto a loaned flatbed trailer and pulled the wagon to Pietersburg (now called Polokwane).

The Landing brake must be pulling too tight against the body, so this will need adjusting, to stop the warping ... no, it is not the sun :-)

The advice from the group was to make a new one ... so we did.

The Hinges seem to be proud by 1mm, and the specified screws sit out in the wind too, So i added two layers to the outside of  the hinge area, then recessed the taper end of the washer shown and floxed this in place. Then replaced the screws with SS taper heads and will finish the micro filler flush with the washer.

It looks faster, even if it isn't :-)



Internal Finish:

 I'll be finishing with a commercially available Hammer tone paint ... It looks a bit like the background to this web page, but with an ever so "subtle" blue/green finish. Its hard as nails, hides a huge amount of pockle and other unmentionables. But I do like the fiberglass weave that show thru, that looks really neat :-)

Universal undercoat is applied to get to the final gaps and spots ... everything shows up now!

It may not show clearly on this photo, but the nose was not round enough, so we ground all the paint away, added (max about 10 mm) micro and some bi cloth and did the finishing all afresh. Although it was round compared to a straightedge, it did not feel right when you ran your hand over it ... now it does :-)

The hand is an awful tool, it picks up the smallest imperfections.

Arthur Smith feels for imperfections.

Now you know why these amateur builders walk around an Airshow feeling things :-)

External finish:

Samples of the color have been done on my Partenavia wheel spats. Simply divine, so beautiful, I could just about lick them :-),

So I sprayed my luggage trailer in this color, to test on a large area - have a beautiful trailer now too!

This view of close fitting parts and color.


The paint used is Spies Hechter - MB511 white base, finished with a clearcoat tinted with 20% Blue Green Perlescent.

Does it shine - you betcha!

Cowling design is superb :-) The top cowling is held with hinges, the bottom is held with screws and hinges, resting on a lip near the firewall.

Removal procedure for one person works like a charm, so does installation.

Removal: undo bottom screws, loosen pins, hold with one hand on the boat tail fin, remove pins all is loose, resting on the firewall lip - remove and put down gently :-)

Top cowling hinge pins are now accessible, remove sides first, then top two pins, by pulling down, everything rests on the (now temporary) baffles, remove and take aside :-)

Arthur Smith is responsible for this super finish.


Chapter 26 - Upholstery

We're nowhere there yet, but I found the most beautiful (to me) material !

No prizes for guessing, but it ranges from black to turquoise, depending on the angle of the sun :-)

Initial flights may take place with the garden furniture seats, until I have determined the correct thickness of the seat required :-)


First Startup at home

This can be a real hit in the neighborhood, if they did not know where you lived, they'll soon be at your door.

360 cubic inches (that's 5,9 liters) with straight stacks is loud!

Note the direct hit of the exhaust on the propeller!

This is because the propeller is not clocked correctly!

When you do install the prop, get # 1 on TDC, then facing the rear of the motor, position the prop in the 13:00 / 19:00 position.

That way the exhaust gasses will pass the blades as they rotate.

It only takes about 45 minutes to kill a perfectly good prop!

The new prop was clocked correctly!


Test flights

Flight # / Description

01 It does fly!

02  Conversion

03 First Solo

04 Flight to prove the oil leak is fixed

05 Seat the rings

06 Refurbished Propeller #1

07 New Propeller #2

08 Slow flight and photo session

09 Normal flight and temperatures



12 Check out the engine

13 Test the new 70 x 80 propeller

14 A short but exciting flight - The Canopy Opens

15 Check out engine & Wheel-Up

16 Check out engine 

17 Speed Run @ 2500 Rpm - WOW

18 Slow Steady Speed & other stuff

Test 19 - Even slower still ... wait for it - no time now

Test 20 - Lets have some fun & visit FAKR ... photos only ... wait for it - no time now

Test 21 - Forward C of G - NOT

Test 2008 05 18 climb


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