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Flair Fokker D.VII Build


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I haven't finished a build since about 2010 and I'm one of those people who ticked the "10+" box on the recent forum poll on the number of unfinished projects. However, I'm currently convalescing at home with quite limited mobility so can't really do much, and I'm finding that the urge to build something is becoming difficult to ignore... the question is, what?

There were several very nicely-flown scale models at the club scale day this year, one of which was a Flair Fokker DVII which looked really good - OK, it's not perfectly scale but as a model that gets flown every week it promises to be quite practical and looks to be very rewarding to fly. I also found a video of Mikael Carlson flying a full-size reproduction D.VII in combat mode:

http://www.youtube.com/watch?v=gZZ82xiWP7w

- it gets interesting after about four and a half minutes. Just magic.

So, that was it; Flair Fokker DVII and other paraphernalia ordered from Sussex Model Centre, modelling room tidied, and let's have a go...

Edited By Andy Blackburn on 14/08/2013 10:24:07

Edited By Andy Blackburn on 14/08/2013 10:24:21

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Since I've not built anything properly for a while, there are bound to be a few (hopefully minor) blunders, but with a bit of luck they'll all be fixable.

Normally the first thing to do would be to join the various plan sheets and steam ahead, but in this case sanity prevailed (for a change) and I read everything on all the plan sheets first. I decided to build the bottom wing first as it's a decent size and is more-or-less required before building the top wing, and since my building board is only partially flat the plan needed to be cut-up to fit. The two wing plans need to be joined, but the plans are not a particularly accurate fit (this seems to be normal):

joined-plan.jpg

...so I just joined them so that the main spar was aligned using a metre rule, and drew any additional alignment marks in pencil.

The basic wing structure is built on 1/16" sheet leading and trailing edges and cap-strips with an enormous beech block for the undercarriage mounting that doubles as a centre-section wing brace, with the wing spars butt-joined in the middle. I was a bit concerned about this but then realised that everything is glued to that huge beech block, so there's no way it's going to break.

basic-wing.jpg

That was the state of play as of first thing this morning; I going to try and post every few days or so (depending on progress) in the hope that maintaining a bit of momentum will make completion a bit easier...

Edited By Andy Blackburn on 14/08/2013 11:05:23

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I suppose I should own up to the first blunder... smiley

The last thing I did the other evening was to number the ribs and cut them out of the 2mm liteply sheets in preparation for gluing the ribs on, but the following morning found that someone had snuck into the workshop and replaced my perfectly good ribs with very similar items, only these were twisted like propellers; Oops. They did steam more-or-less straight eventually but it was a bit of a pain in the neck, must try and remember not to take them out of the sheet until they're about to be used.

Ribs and spars were added in the usual manner:

ribs-added.jpg

I thought the holes in the wing brace might be a bit tricky, but it turned out to be straightforward because you have that substantial undercarriage mounting block to rest the dowels on when marking out and checking alignment. I did find, though, that a couple of extra alignment lines for the inner ribs on the bottom sheet were extremely useful, it would have been better to add these right at the start.

This is where it's got to at the moment:

almost-finished.jpg

The centre section sheet was a bit of a pain, the leading edge sheet is joined using a scarf joint which doesn't react well to the wood being curved (I think you can just see that it hasn't curved properly at the centre section in the picture above). 

(TBH, I'm not sure a scarf joint is really necessary for the LE sheeting - it might be better to add an extra couple of thick riblets to the two centre-section ribs and then butt-join the sheeting on the thick ribs - this should be OK as long as the top and bottom sheets were joined on different ribs. And that would also do away with the requirement to join the LE sheeting before assembly.)

Still to be added is centre-section sheeting, top cap-strips, wing tips and trailing edge scallops. So far, it's quite an enjoyable build.

Edited By Andy Blackburn on 17/08/2013 16:47:53

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Progress has been made, but it's time to own up to blunder number 2, I think smiley.

For some reason that escapes me now, I didn't join the left and right half of the bottom leading-edge sheeting over the plan, I drew a line on the board and used that as a reference - which would have been fine if everything was straight but in this case the parts were slightly curved, so I joined them such that the centre section was straight. This would have been fine if I'd then paid a bit of attention to where they should have been placed on the plan... anyway, it transpired that on one wing half, there wasn't quite enough wood on the bottom leading edge sheeting to overlap the leading edge:

oops-2.jpg

...as you can see from the daylight peeping through next to the leading edge in the picture. I had to fix it with masking tape, 1/4" x 1/16" strip and slow cyano, I'm sure no-one will notice once it's covered.

The tip parts are a bit over-size, which is good because everything can be sanded doen to size:

lower-tip.jpg

The trailing edge scallops were, if I'm honest, a source of some concern as it looked to be very easy to take too much off. After a bit of thought, I made a card template, drew the scallop outlines in pencil, cuit outside the line with a new scalpel blade and then used a strip of 80 grape sandpaper stuck to a piece of scrap 3/8" balsa sanded to a semi-circular shape to sand everything down to the right size. This seems to have worked reasonably well:

te-scallop-template.jpg

And here's the (almost) finished product after the first sanding:

lower-wing-structure-finished.jpg

...it's missing the wing fixing reinforcement for pegs and wing bolt, and the strut fixings, and weighs slightly less than 6 ounces. Not quite sure what to do about the strut fixings yet (12 sets of nuts and bolts to lose at the patch or leave at home is probably rather too many!), so I'm going to leave them off for the moment and have a think about it while starting on the top wing.

Edited By Andy Blackburn on 20/08/2013 21:48:55

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Delighted to see another one going together, my one is looking decidedly tatty after several years storage and a hard life before that. I have another kit in my loft and hope to build it over the winter. It's been in my loft for at least 13 years, it was about £85 when I bought it so that gives some idea of the age. I have some of the paint by numbers lozenge solartex and a laser 80 from out the old one and the necessary tins of paint (same age so don't know if they'll be any use) machine guns, wheels and vynil crosses.

One thing well worth paying attention to is the method of fastening the struts and cabanes etc, it is so much easier if the machine screws are fastened to the mountings on the wings and fus so the struts just slide on then a nut runner to tighten the nuts, I used 3mm stainless allen bolts and nylocs from modelfixings. Also the hard points in the wings and fus, I've already cut 4mm birch ply ribs and fus doublers to mount the mounts on. I also changed the original wire struttery to 2mm alloy strip faired with balsa and covered with heatshrink on DV11 no1 and I'll do the same for no 2 but might use mild steel instead of alloy if I can get 6mm x 2mm section.

Sorry to rabbit on.

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Posted by Braddock, VC on 20/08/2013 22:44:00:

<snip>

One thing well worth paying attention to is the method of fastening the struts and cabanes etc, it is so much easier if the machine screws are fastened to the mountings on the wings and fus so the struts just slide on then a nut runner to tighten the nuts, I used 3mm stainless allen bolts and nylocs from modelfixings. Also the hard points in the wings and fus, I've already cut 4mm birch ply ribs and fus doublers to mount the mounts on.

<snip>

So, have the centre-section bolts captive in the wing and the centre section strut ends bent horizontal so that the wing can just be dropped onto the cabane struts and attached with four nuts? Good idea, as is the concept to replacing bolts and nuts with metric/nyloc equivalents...

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Posted by jeff2wings on 21/08/2013 07:09:30:

Hi Andy , makeing good progress thereyes ,the nuts for strut fitting are solderd to the lugs for a diffrent way of doing it have a look at my Flair Legonaire re-build thread ,the N struts as kit are fine no need to over-engineer

Edited By jeff2wings on 21/08/2013 07:12:29

Ah, OK, so use slightly thicker ( 1/16" ) mild steel plate for the strut attachments and just tap the plates M2? Good idea, and possibly less hassle than soldering nuts, although it would require a source of mild steel plate and an M2 tap.

I was originally thinking that, since there's no bracing and since the interplane N-struts don't appear to be structural (other than to transfer mild impact loads to the top wing if one were to have a take-off or landing incident that involved the lower wing contacting the runway), maybe it might be possible to dispense with nuts and bolts altogether? Maybe having the N struts semi-permanently attached to the top wing using wire in brass tubes, and then having the lower wing N-strut attachments simply bent rearwards so that they can slide into brass tubes as the bottom wing is inserted into the fuselage from the rear? Might require a bit of manual dexterity, but there are then no bolts on the N-struts...

Edited By Andy Blackburn on 22/08/2013 09:48:31

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Andy,

How about adopting the Hanger 9 approach for joining the N strut. I tried to explain to you the other day but a picture speaks a thousand words.

img_0957.jpg

The N strut has to inserted at the top first, the angle of the wire stops them coming out.

img_0958.jpg

The bottom ones are held by brass collets. I hope it's clearer now.

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Posted by Scott Edwards 2 on 24/08/2013 11:28:11:

Thinking ahead ..... Colour scheme ?

Well, it's got to be mainly 5-colour lozenges, really. I haven't got any pre-marked solartex, but it won't (shouldn't) take long to cut some templates and make some - the alternative to painting is to airbrush it, and the overspray will probably get everywhere...

 

Edited By Andy Blackburn on 26/08/2013 20:20:50

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There has been a small amount of progress this weekend, less than originally hoped because the building board had to be properly straightened using old magazines and match-sticks as packing, with recalcitrent corners held down using gaffer tape; however, in order to do that the board had to be cleared, and in order for that to happen the desk drawers had to be cleared because there was just nowhere else to put anything. I found a set of till receipts from 2002 at the back of one of the drawers...

Anyway, we're starting on the top wing. The kit is 20 years old and shows a firly complicated aileron servo arrangement with a fuselage-mounted aleron servo driving the ailerons via three bellcranks, but obviously the best way to do it is to have one servo (HS85 MG) driving each aileron as shown here:

aileron-hatch-plan-hs85.jpg

So, the servo is mounted directly on the hatch which is held by four screws that go into 3mm liteply; thr parts are here:

aileron-hatch-parts.jpg

The edges of the wing cut-out will be reinforced with 1/8" x 1/4" or similar. Not sure what to do about the servo wires, maybe have an extension lead going up the front cabanes.

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I think bellcranks are Ok as long as ball-links are used everywhere

> ...looking forward to seeing those Lozenges (rather you than me though mate ...)

I'm still looking for ways to cheat with the painting, but I suspect that it'll come down to using paint masks and tidying-up the edges by hand afterwards - long way off that yet, though.

Anyway, after a bit of a medical-induced hiatus (and a failed experiment to see if it was possible to flatten the sheets of liteply that contains the ribs), I'm getting back on track. This is where it's got to as of about 4 pm today:

top-wing-1.jpg

Having built the bottom wing, the top wing is probably a bit more straightforward; bottom LE, TE & capstrips, then spars, then ribs & webbing, then top LE/TE/capstrips. It'd probably be easier with thin cyano, but (in common with many people) I'm sensitised to the stuff and can't use it anymore.

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If you didn't want to paint the lozenges by hand, there is, or was a firm called Wildmann Graphics which produces or used to produce pre-printed lozenge Solartex in a number of different scales.

I'm not sure whether they are still trading and I haven't been able to access the site, www.wildmanngraphics.net but the proprietor gave out his phone numbers on another website in 2009. These are 406 260 4088 or 406 871 0563. If phoning from outside the USA you will need to start with the international code 001.

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