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CAP 20L build


Peter Miller
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Looking for something to design and having just lost a favourite model I seemed to suffer from designer's block.

Then I thought about another of my favourite models, my old and still serviceable CAP 21. Now I know that this model was popular and so I decided to do the earleir CAP 20L. THis has the advantage that it uses the same fuselage I am lazy!

Contruction follows my usual system. Fuselage sides with ply doublers.

cap20 blog (3).jpg

Pull in the sides at the rear and add the spines.

cap20 blog (7).jpg

The glue the turtle deck sheet to the sides and leave to dry.

cap20 blog (11).jpg

Apply water to the outside of the sheets and then  heat witha  heat gun and bend over and glue and pin in place

cap20 blog (15).jpg

 

Edited By Peter Miller on 29/09/2012 11:20:00

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The wings are built on the board. The lower LE sheet, the trailing eghde sheet, Capstrips under the aielroin spar and aileron leadign edge are pinned down. The spar is glued to the sheet and then the ribs are added.

The undercarriage mount is glued to the ribs. The ailleron trailing edge is fitted and the aileron ribs are installed. Note that the lower aileron rib capstips shout fitted to support the ribs.

Note that only one wing has the root rib glued in. theother wing does not have the rib fitteing until they have been joined.

cap20 blog (5).jpg

The Leading edge is glued in place and the various blocks for the hinges and the triangular stock as added to reinforce the undercarriage mount. The lower leading edge sheet is raised and glued to the leading edge. Spar webs can also be fitted now.

cap20 blog (8).jpg

Detail of undercarriage mount

cap20 blog (9).jpg

The leading edge sheet can be glued down to one wing at this stage.

cap20 blog (13).jpg

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Yes, that was one of the main reasns for choosing it. Similar enough to be sure that it would fly well but different enough to be interesting.

That is a CAP 20 in your picture, not the 20 L. You can tell by the angle of the rear of the canopy. Also, the wings are slightly longer and even more elliptical at the tips.

Edited By Peter Miller on 29/09/2012 12:01:58

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Posted by Peter Miller on 29/09/2012 12:00:28:

That is a CAP 20 in your picture, not the 20 L. You can tell by the angle of the rear of the canopy. Also, the wings are slightly longer and even more elliptical at the tips.

Ah yes, I hadn't noticed that. Good spot.

Looks like you'd better get cracking then, Peter. I forsee a demand for a CAP 20 plan as the third model in this series wink

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I expect that it will be a free plan, the CAP 21 was. Don't hold your breath though, there is another of my plans in the editor's in tray first.

It will be a long time before I do the CAP 20 but you can easily adapt the 20L to a 20.

Yes, I will do the wing fairings, they are very small and look quite simple. So small that I had not really noticed them.

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The CAP 10 is much wider. I might, one day, decide to do a Piel Emeraude.

Thanks for the comments on the pictures. Forced into that. Takes an age to set up the "studio" in my bedroom.

I have chosen an unusal colour scheme. An Italian aircraft. Also has the advantage that you can fly it without spats if you want to although I will not

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Peter,

I have flown a Piel Emeraude, a friend of mine had a part share in the Emeraude based at Newcastle aero club.

Went up twice with him and I had control from just after t/o up the east coast to Alnwick Castle and back to Newcastle,a great experience.

The aeroplane was old,.the joy stick looked like a piece of conduit pipe with a rubber bicycle grip and a little red button on top for the radio,chock block connectors hanging from the dashboard.

I'll never forget it, it certainly would make a great model

Jim

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Right, Back again

WE start off with my method of building the cowl. The spinner is glued to the cowl front with CA and 1/16" spacers. This works especially well with cowls that match the spinner.

cap20.2 blog01.jpg

THen I glue in the balsa betwen F-1 and the front of the cowl,

cap20.2 blog15.jpg

cap20.2 blog16.jpg

The engine is removed and the cowl carved to shape. The apple cheeks are added and shaped and blended to match.

cap20.2 blog04.jpg

cap20.2 blog05.jpg

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One wing is completed including the LE sheet. It is then liftted frcom the board. This makes sure that it cannot warp once removed from the board.

The other wing is left pinned down and the completed wing is joined to it at the correct dihedral angle. Only then is R-1 fitted to the the second wing.

Showing R-1 being fittedcap20.2 blog14.jpg

cap20.2 blog17.jpg

Once the wings have been joined the sheet can be added to the second wing before it is lifted off the board. The centre section sheet is now added.

cap20.2 blog06.jpg

Edited By Peter Miller on 06/10/2012 11:40:47

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use a central servo and bellcranks out in the wings. This keeps the weight away from the tips. It will improve precision rolls and four point rolls. At least, it will for better pilots than myself!

cap20.2 blog07.jpg

Here is a tip for cutting neat radii in the centre section sheet. Use a sharp circle cutter.

cap20.2 blog12.jpg

The tails parts are pretty simple. However I use a cutting disc to make a recess in the horn balance and add lead as amass balance. This prevents flutter. The rudder is huge and it is important.

cap20.2 blog10.jpg

The other job is the spats and undercarriage.

The spats are built from balsa with ply at the wheel position. They are held to the legs with brass saddle clamps whih are soldered to the legs.

They will be faired to the legs with David's Isopon or similar body filler

cap20.2 blog08.jpg

 

Edited By Peter Miller on 06/10/2012 11:51:00

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  • 2 weeks later...

Been a bit slow in updating this blog.

Two shots of the aileron controls.

millers tales 002.jpg

Withe the ailerons still attached to the wing I temporarily install the horns and pushrods so the everything is set up. They are then removed and the model is covered.

millers tales 003.jpg

The aileron servo is mounted using Radio Active Servo Mounting Brackets. Note that the servo will be clamped down and there will be a swing in keeper on the aileron connection.

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Yesterday Was nearly perfect, just alack of blue sky. However a few of us got together on the field and I was able to test fly the CAP 20L

cap 20l static 015.jpg

cap 20l static 002.jpg

cap 20l static 001.jpg

Colour scheme is taken from a CAP 20L belonging to an Italian club.

cap 20 flt 071.jpg

cap 20 flt 065.jpg

I knew that the model would be nice because it is so similar to my CAP 21. However I think it is even better in some ways.

Rock solid in flight, especially in inverted flight. Does lovely axial rolls. Does the sharpest, most positive four point rolls that I have ever done with instanyt start and stop.

Does nice square loops, haven't tried square loops with quarter rolls yet.

Great for knife edge but I must practice as she keeps climbing in knife edge.

Stall is a total non event, refuses to dropa wing however brutal one is.

Spins, both upright and inverted are great and she stops instantly.

Takes offs are smooth. Landings great

I now have another favourite.

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