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Cliff Charlesworth Olympia build in Bishop, CA.

Let us all watch your new project progress.
Greg Smith
Posts: 130
Joined: 26 Jan 2016, 00:20

Re: Cliff Charlesworth Olympia build in Bishop, CA.

Post by Greg Smith »

So I've started to lay out the wing ribs: no gluing quite yet. Nice thing about building this model is that because I'm in no hurry, I'm actually thinking ahead a bit and not rushing into mistakes or bad workmanship just to get things done. A rare luxury! If someone in the next generation completes the model, so be it.The only reason I do want to finish is to clear the building board for the next exciting project, but since I haven't decided what that will be (apart from a DLG Libelle, which could be done in the clear space still existing) I'm taking my time. Case in point: since the ribs are not perfectly slotted and don't quite line up along the plan, which end of the rib is the most important? I decided it's the T.E., since a short rib at the L.E. is much easier to correct. I'm also taking the time to make sure that every rib is right on the line, and that the spar slots are deep enough. In the past, I've often removed a wing from the board to see the spar protruding from the rib profile... Horrible sanding is then required, destroying the perfection of the longtitudinal profile! Still flies, though. Anyway, nothing but my best is good enough for this model. Probably spoil it all with the finishing? Couldn't have got this far without the expertise of gentlemen on this site, though.Oh, Peter, I've found that I had to pack up the rear spar by 1/16", but the rib sits on the main spar quite nicely. My main spar shaping leaves something to be desired, though. I thought of a solution to the perfect taper problem, but I doubt I'll do it: two 48" straight edged, drilled for compression bolts, spar sandwiched between, with the cuttable/sandable portion protruding above the metal edges. I wonder if anyone has done this?
Greg Smith
Posts: 130
Joined: 26 Jan 2016, 00:20

Re: Cliff Charlesworth Olympia build in Bishop, CA.

Post by Greg Smith »

Is it possible to go back and edit one's post? I noticed I wrote 'edged' not 'edges'.
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Peter Balcombe
Posts: 1399
Joined: 18 Mar 2015, 10:13
Location: Clevedon, North Somerset, U.K.

Re: Cliff Charlesworth Olympia build in Bishop, CA.

Post by Peter Balcombe »

Greg,
Yes, although it appears only to be possible until someone has replied to the post - but I am sure an administrator can then sort it upon request.
Just click on the ‘edit’ (pencil?) symbol in top right of your post & you can edit & repost.
Greg Smith
Posts: 130
Joined: 26 Jan 2016, 00:20

Re: Cliff Charlesworth Olympia build in Bishop, CA.

Post by Greg Smith »

Thanks, Peter! I just added this...
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Peter Balcombe
Posts: 1399
Joined: 18 Mar 2015, 10:13
Location: Clevedon, North Somerset, U.K.

Re: Cliff Charlesworth Olympia build in Bishop, CA.

Post by Peter Balcombe »

Greg,
Sorry, but don’t understand your proposed solution to the spar taper problem. Perhaps a photo would clarify.
Greg Smith
Posts: 130
Joined: 26 Jan 2016, 00:20

Re: Cliff Charlesworth Olympia build in Bishop, CA.

Post by Greg Smith »

Oh- it's just an idea, Peter: I haven't made it (yet). So, I have a very substantial Starrett 48" straight edge. About 12 dollars from Amazon. If I bought another, I could put them back to back, with two or three bolts through both, with wingnuts for tightening them together. I would put along one edge a piece of wood of the thickness of the spar to be tapered, and along the other edge the spar itself: in effect, making an impromptu vice. The spar would protrude to the required degree of taper, then I would sand off the exposed edge. What would remain between the straight edges would be the shaped spar. Hope this makes sense. I'm persuading myself I might make one for the second wing... Any artificial aid which will improve my accuracy is welcome, but there's a limit to the amount of trouble I'll go to, as well!
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Peter Balcombe
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Joined: 18 Mar 2015, 10:13
Location: Clevedon, North Somerset, U.K.

Re: Cliff Charlesworth Olympia build in Bishop, CA.

Post by Peter Balcombe »

Ok Greg I understand now.
Sounds as if it may work if you can set it up ok.
To be honest, as I tend to taper spars on only one side (keeping the other edge flat as produced), I just calculate the required thicknesses at a number of points along the strip, mark these points, then steadily plane/sand away using a David plane/Permagrit block until the thickness at each point is as close as possible to that required when measured using a digital calliper.
If I can get each point within a 0.1mm then I am happy.

If tapering a spar depth, then I will only taper what will be the inner surface, then the outer one will always be flat.
If tapering a spar in width then I tend to taper the opposite side to that which will be against the spar web.
That way, the majority of the mating surfaces will tend to be flat and square.
Greg Smith
Posts: 130
Joined: 26 Jan 2016, 00:20

Re: Cliff Charlesworth Olympia build in Bishop, CA.

Post by Greg Smith »

Makes sense. I used your Permagrit method and then a long sanding bar, but I wasn't too happy with the waviness which resulted: lack of skill/practice, I expect. One spar also took a long time.
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Peter Balcombe
Posts: 1399
Joined: 18 Mar 2015, 10:13
Location: Clevedon, North Somerset, U.K.

Re: Cliff Charlesworth Olympia build in Bishop, CA.

Post by Peter Balcombe »

Greg,
I use the razor (David type) plane to remove most of the material & then finish off with the coarse/fine sanding blocks.
A pencil line along the spar helps tell when close enough to start checking measurements.
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RobbieB
Posts: 547
Joined: 07 Mar 2015, 22:22
Location: North West

Re: Cliff Charlesworth Olympia build in Bishop, CA.

Post by RobbieB »

Greg,

It will be very helpful to support the spruce spar flange with scrap block/ply when you are planing it as show in the photo below making sure the blocks diminish in depth below that of the spar as you progress out to the tip.

It is also worth mentioning that in full size practice it was unusual to reduce the flanges thickness out towards the tip, only the width. Not in every case but usually.
m100_spar.JPG
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