Corby Starlet 52" RCME sept 2012

[Tony K]

The formers for the front upper sheeting are glued in place.

Before closing off the front, the motor is test fitted to check the clearance...

...and the front upper is planked. I couldn't get a sheet to fit the double curvature.

Turned out quite well for a first effort.

Returning to the back end, there is another deviation from the plan. The tailplane sits on two bearers which are tapered towards the rear to save a bit of weight. Then the longitudinal former is fitted. A fin mounting plate is cut to the exact size of the fin base and is located to it with two dowels. The fin and the mounting plate are then carefully aligned and a few drops of CA fix the mounting plate to the longitudinal former. After the CA hardened I added triangular section supports and a good fillet of white glue. The fin can then be removed to avoid damage while the end of the fuselage is finished.

Here is the fin in place on the mounting plate.

[Tony K]

Now with the rear end of the fuselage finished, the fin can be finally glued in position. I used cardboard formers to ensure vertical alignment.

This is how it looks after final assembly and finishing.

Starting to look like an aeroplane.

As a change from making balsa dust I had a go at an instrument panel.

Not too bad but I might do another one with lighter coloured card for more contrast.

[Ton van Munsteren]

Tony,

Well done, great to see that the Corby is coming to life, .

Your a great craftsman the build looks very smooth and accurate.

Very nice instrument panel and yes your right about the colour it could use some more contrast to make it even better.

Thanks for the pics and please keep on posting them.

Ton

[Tony K]

A bit more progress. Some soft 12mm pieces laminated together...

...and after a bit of carving and sanding.

[Ton van Munsteren]

Tony,

Very nice balsa work, beautiful shaped and very smooth.

Really starting to look like a Corby.

Ton

[Ton van Munsteren]

Tony,

Any update about the Corby.

Ton

[Tony K]

Ton, work is still going on. I made a start on the wing assembly but I did not take any pictures of the build because they would not be any different to yours (and Erwin's). I have some pictures of the nearly finished wing but I have not been able to upload them. My internet connection has been very slow in the last few days.

[Tony K]

OK, I managed to upload some pictures last night. Here is the (39 inch) wing.

As a change from the plan, I "squared off" the trailing edge at the centre section. This is the underside.

View from the top. I have built in a plywood plate which the mounting bolt psses through. My intention is to fabricate a bracket fixed to the fuselage former F5 which the bolt will screw into.

Looks a bit rough in the picture but still needs a final sanding after the leading edge is fitted.

Currently working on the servo hatches. The smaller wing is too thin to mount the servos with the spindle vertical as shown on the plan so I am going for the more conventional layout with the servo arms protruding through a slot.

[Tony K]

Here are a couple of the "put it together and see what it looks like" pictures.

As a reminder to anybody following, this is being built from the originally published plan which had so many errors although I have made a few changes along the way.

[Ton van Munsteren]

Tony,

What a great job the Corby is a beauty.

Ton

[Tony K]

A few updates. This is the spring latch for the hatch cover. Some ply offcuts, a piece of wire coathanger and a biro spring.

The dodgy joint at the top left corner has been sorted.

The wing fixing bracket. Epoxied and pegged to the fuselage former.

Elevator and rudder servos. Nothing unusual.

A bit of scribble to work out the aileron linkages. This geometry gives 29 degrees up and 20 degrees down at full throw.

Aileron linkage.

Servo in place.

Next big problem is the canopy. I have searched the supermarket shelves for a suitably shaped clear drink bottle but as yet not found anything.

[Ton van Munsteren]

Tony,

Any luck with the canopy

Ton

[Ton van Munsteren]

Tony,

Would love to seen an update and I do hope that your Corby is flying already.

Ton

[Roger Mason 1]

Hi Ton. I have just completed construction of the 74% version using just the published plan. I note that there are no suggested control surface movement figures in the magazine article or on the plan. Any suggestions for a starting point? Roger Mason from New Zealand.

[Ton van Munsteren]

Hi Roger, That's great news never expected to hear that a Corby is close to ready to its maiden.

Would love to see some pics of the Corby I sure its a lovely model to see in its 74% scale.

For the control movements not sure what to say because most of the time I use to much control movement on my models, that's what other pilots say when they fly my models.

I think that for elevator and aileron it will be just fine with 10mm max both ways and for rudder is could be a little bit more.

Hope this help you a little.

Cheers

Ton

[Roger Mason 1]

Hi Ton. Thanks for your response. It will be a starting point although I am sure the throws will be changed to match my flying style. I will get photos when everything is finished. Roger

[Ton van Munsteren]

Hi Roger, That would be great looking forward to the photos.

Ton

[Roger Mason 1]

Hi Ton.
Just an update.
Model is complete except for canopy which I hope to mould tomorrow. Airframe weight came in at 650 grams and ready to fly at 1030 grams. Had to replace motor due to a noisy bearing which then required new prop adapter.
Will get pics once canopy is fitted.
Regards,
Roger

[Ton van Munsteren]

Hi Roger,

Great really looking forward to the pics.

Ton

[Roger Mason 1]

Hi Ton,

Some pics taken on my phone. More to come.

[Ton van Munsteren]

Roger, Thanks for the pics that's a beauty, for its 74% it looks big.

Ton

[Roger Mason 1]

Hi Ton.

Just a couple of pics - one to show what the pilot has got to look at while I fly him around the sky, and another to show the size comparison between the Starlet and my Red Eagle.

Note both pics are inside my garage - the Spring weather hare has been either too wet or too windy or both. Our club field is very wet and the grass has not been mown as the mower would sink into the surface and leave ruts.

Model is ready for maiden flight as soon as weather allows.

Regards,

Roger

[Ton van Munsteren]

Roger, woooo thanks for the lovely pics like the cockpit with dash and pilot in the Corby.

Must have been lots of fun to make and makes the Corby just perfect.

I do hope you enjoy both models, as I still do myself, because both prototype models for the plan still fly great.

Must admit that with the mistake of the plan size, the Corby looks great and could be a nice size for another design.

Must admit those experimental homebuild planes make great models.

Just a small question what motor and prop will you be using in the Corby.

Enjoy the maiden and looking forward to lots of pics or even better a vdo.

Cheers

Ton

[Roger Mason 1]

Hi Ton,

Thanks for the comments. The build was interesting as there were a few different techniques which required thinking about before acting. The ply and balsa materials had to be a nominal 75% thickness to keep the weight down. I left the wing ribs at the same thickness for ease of handling, and the fuselage sheeting in front of the cockpit had to be planked because of the dual curvature.

The motor was going to be a Dualsky 3530 1200Kv but, because a noisy bearing, a Dualsky 3536 1200Kv (maximum 350W rated motor) was installed (same mounting holes). A 30A ESC was fitted along with a 3S 2100 battery. Static current draw on a 9x4.5 prop is 18A (approx. 200W) which gives a power rating of just under 100W/lb. This is very close to one of my aerobatic models so should be plenty of power.

Will let you know about the maiden flight - could be this coming Thursday or Friday if the weather plays its part.

Regards,

Roger

[Roger Mason 1]

Hi Ton,
Finally the weather is suitable for flying. Have maidened the Starlet but had to add side and down thrust to make it flyable. Remaining problem is to do with control throws - elevator is very sensitive but I need a reasonable amount to keep from tipping over on takeoff from mown grass field. I am investigating a couple of options to provide enough elevator authority for takeoff and landing flare but give reduced throw for normal flight.