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Geoff S04/12/2020 15:57:21
4025 forum posts
68 photos
Posted by Fun Flyer on 04/12/2020 15:20:06:

Its well known that anything that's designed not to be removable will need to be removed sooner rather than later!

There's an element of truth in that

So you could make the cowl removable simply by using locating dowls (cocktail sticks work well at about 2mm dia) but relying on the film covering to hold it in place. Easy to remove with a scalpel; not so easy to replace as it would need the covering to be replaced/reinforced but it's not going to be a frequent need.

Geoff

Trevor04/12/2020 16:31:16
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564 forum posts
66 photos

I was about to make the same suggestion as Geoff. If you’re concerned about it getting untidy if/when the cowl has to be removed, you could cover the cowl separately then attach it with a strip of matching covering which can be removed and replaced if the need arises. Basically, it’s just a slightly upmarket way of taping the cowl in position!

Trevor

john stones 1 Moderator04/12/2020 16:37:39
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Moderator
11908 forum posts
1531 photos

How about splitting horizontally, fix one half on easy enough, the other fits to that ?

NigelS04/12/2020 17:38:45
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47 forum posts
166 photos

Back in the summer this was the first time using those strong rare earth magnet on a cowl.

They are available from many on line purvayors.

Make sure north/south oriented (they are so strong they sort emselves anyaway). 6mm dia 3mm thick - 6mm ply firewall and thinner lightply on balsa cowl prior to the balsa.

Drill through light ply into 6mm firewall - don't go right through e.g. 3mm deep. Drop of epoxy in bottom hole electrical tape between facings to stop sticking. instant fixing which snap into place.

As the prop/spinner is in from It cannot fall off in flight anyway.

Here you can see marked positions Six places middle ones for 6mm alignment dowel(s)

91_cowl_interface_plate.jpg

Ready for the magnets...

93_cowl_interface_and_f1_drilled_for_location_pegs_magnets.jpg

Cheeks added

94_building_blocks.jpg

Carving/Sanding

103_acro_star_nose_job.jpg

Painted ready for rest of covering.

This just pulls off (with quite a tug) once spinner and prop removed.

117_finished_carving_sanding_painting_cowl.jpg

It's now going to my standard method for cowl on sport jobby.

EarlyBird04/12/2020 20:07:00
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632 forum posts
445 photos

Thankyou everybody. Your combined effort has convinced me not to give up. I have made a few adjustments and can now get the 6mm vertical movement needed for the keyhole fixing method, but I do like the magnet idea.

I had not given up just stalled, which I am told is not a good idea in this hobby. laugh

I could have fixed the ESC and motor in permanently because, so far, they have always lasted longer than the aeroplane. laugh

Filled with new enthusiasm I have cut some balsa and glued it in place.

Once again thanks.

Cheers beer

Steve

Peter Miller04/12/2020 20:40:02
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11758 forum posts
1416 photos
10 articles

Never give up! Just think about it and a solution will be found

Fun Flyer04/12/2020 20:56:58
365 forum posts
59 photos

A perfect description NigelS.

EarlyBird05/12/2020 10:17:03
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632 forum posts
445 photos

FF I agree.

NigelS your pictures provided me with a solution thank you. idea

Cheers beer

Steve

EarlyBird06/12/2020 10:51:48
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632 forum posts
445 photos

Progress on the cowl.

Sides glued on and bottom pinned in place.

img_20201206_100821814_hdr.jpg

Sides trimmed along the bottom.

img_20201206_101247120.jpg

Glued and clamped.

img_20201206_103327123_hdr.jpg

That was not difficult smiley

Cheers beer

Steve

EarlyBird07/12/2020 11:22:27
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632 forum posts
445 photos

I am gradually adding bits of balsa.

Here I am test fitting to make sure that when in place that the cowl can be removed.

img_20201207_095652197_hdr.jpg

Good job I did because this time if I had glued it the cowl would not have come off. Near miss I think blush

Am I the only one who has to go this long winded process?

Working on the top of the cowl next.

Cheers beer

Steve

Trevor07/12/2020 11:33:54
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564 forum posts
66 photos

No Steve, you are not the only one! I’ve just been through a similar exercise in 3D visualisation with the cowl on my Aeromaster - **LINK**

Trevor

Trevor07/12/2020 11:37:02
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564 forum posts
66 photos

No Steve, you are not the only one! I’ve just been through a similar exercise in 3D visualisation with the cowl on my Aeromaster - **LINK**

Trevor

Fun Flyer07/12/2020 11:41:55
365 forum posts
59 photos

Yes EB, the only option I'm afraid is, pin, glue, cut, carve, check, repeat!

You're getting there...

Fun Flyer07/12/2020 11:49:45
365 forum posts
59 photos

Since we're on the subject of Fourniers, aren't these nicely done,

Motor Gliders

EarlyBird07/12/2020 21:45:33
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632 forum posts
445 photos

Thanks Guys

Aeromaster looks good as do the Motor Gliders.

The cowl.

img_20201207_213258496.jpg

Apple cheeks to add then the fun part, Razor Plane time, followed by sanding.

Cheers beer

Steve

EarlyBird09/12/2020 11:34:43
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632 forum posts
445 photos

Apple cheek balsa and carving started.

img_20201209_112327420_hdr.jpg

There is a lot of balsa to remove and I am hoping that I don't end up sanding fresh air laugh

Cheers beer

Steve

Fun Flyer09/12/2020 12:52:24
365 forum posts
59 photos

It's starting to look more like a Fournier all the time.

EarlyBird09/12/2020 16:17:07
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632 forum posts
445 photos

A bit of a mess but I will sort it out. I am starting to see my way forward on this and will add the cheeks on the other side before carving the whole thing at once. This could take some time!

EarlyBird11/12/2020 09:04:18
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632 forum posts
445 photos

As promised both sides now have cheeks.

img_20201211_083355685.jpg

and the carving has started.

Interesting for me but the shape probably will not pass scale scrutiny. I would like perfect but will settle for TLAR.

It's all good practice for the next build, that's the way I look at it.

Cheers beer

Steve

Geoff S11/12/2020 12:01:53
4025 forum posts
68 photos

I find carving a lumps of glued together soft balsa one of the most satisfying parts of building. I know some hate it, but I find it's like being a sculptor Suddenly all the joins become almost undetectable and the surface becomes soft and smooth to the touch.

One thing I'd advise is to remove as much as possible with a knife(scalpel) or plane to keep the dust minimal and I suppose wearing a mask is advisable but I'm a bit remiss in that way. It'll look great, Steve and TLAR is the right thing to aim for.

Geoff

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