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Author Topic: F1A Wing Jigs  (Read 6817 times)
Baz599
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« on: February 26, 2010, 11:02:29 AM »

I want to obtain a set of F1A wing building ‘jigs’ (not the rib jigs) to build a set of carbon wings. Does anyone know where I can obtain these? Several people I have asked said they use ‘Maxwell’ jigs but that of course is no longer an option.

Or is it a case of trying to make a set myself?
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CHE
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« Reply #1 on: March 01, 2010, 03:51:21 PM »

This is such a good question as I know of few or any commercial maker of jigs that reach the 'Maxwell' standard. If you don't need to pin anything down then a few people use plaster mounds.If you do need to pin then I've heard about rotary sanding of various materials, hot-wire cutting of foams with a suitable cover and CNC cutting of solid wood.  Then again, Joes's methods have been published but are very time consuming.

Perhaps a reasonable compromise is the method used years ago consists of a baseboard with wood ribs and ply skinning. All materials are to hand, manufacture is easy and you can pin through the surface.

Sadly so many models are bought or comissioned (wonder what these guys use now, I'm told Stamov bought from Maxwell at one time) that there is little point is setting yourself up to make such things.

CHE

PS Just thought, you could try Mike Francis of rocket fame. I think he has a CNC cutter that me makes jigs from.
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Baz599
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« Reply #2 on: March 01, 2010, 04:37:02 PM »

Hi CHE
It would be possible, I guess, to make a mould from a set of existing wooden jigs; I have done a reasonable amount of fibreglass work to be able to do this. The problem is finding someone who is prepared to either make a mould or lend me their jigs to make a mould. I have tried ‘W-Hobby’ to see if they would sell me a set of their jigs they supply with their kits but without success. I could of course spend a vast amount of money and buy a ‘Hobby wing kit’ and I would then have a set of their hard foam jigs but I have never been a ‘kit’ person.
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PeeTee
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« Reply #3 on: March 01, 2010, 06:42:19 PM »

I built a coupe wing jig using the method described by Lord CHE. It was circa 15" long, and I used a bit of 1/2" MDF as the base. The ribs (shaped to the airfoil undercamber) were cut from some scrap 3/16" and block sanded, glued to the baseboard (from memory at about 1" spacing, and covered with hard 1/8" sheet balsa. It's easier to stick pins into balsa than ply - and glassfibre come to that. A couple of hours saw it done & dusted!

Peter
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binbag
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« Reply #4 on: March 03, 2010, 09:53:56 AM »

This is just the ticket. Lord Che, thanks for the information as I am just about to build some F1B wings, and a building board will be necessary and very beneficial.

The other thing I am looking at is the Martin Dilly/Phil Ball method of making ribs from laminated balsa as described in the free flight forums. I can recommend these as there is a goldmine of information in these, hence I have been buying up back issues with great gusto.

Isn't this forum just wonderful. It now knows how to mind read.
Binbag
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CHE
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« Reply #5 on: March 03, 2010, 10:34:26 AM »

The rib slitting method is interesting but really only lends itself to either parallel wing/tail sections or production of lots of models due to the waste involved etc. What I'm looking at a bit more seriously is getting ribs laser cut at Bellair or in the US. Has anyone any experince of sending anyone CAD files, coordinates or sketches and getting a good end result ?

Of course this doesn't give you the carbon capping but I can never seem to make a spar height accurate enough to get such ribs to fit exactly - any tips ?

CHE - Mind Reader to the Stars
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tonymat
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« Reply #6 on: March 04, 2010, 03:56:39 AM »

I've helped friends get ribs laser cut with good success. Bob Holman in the USA produced them and he requires a CAD file in the AutoCAD .dxf or .dwg format (pretty standard). Most of the laser guys will walk you through the process of how to locate the ribs and so on.
Bob Holman is at: http://www.bhplans.com/LECPg1.html
He'll supply a .pdf file with all the information on how he needs the CAD file configured for laser cutting if you ask.

I made some F1B jigs some years ago using the following method:
-produced nice CAD file of the root, d-break and tip airfoils (I used AUTOCAD)
- sent the CAD files to a machine shop with wire EDM (electrical discharge machining) capability to cut steel templates to a high degree of accuracy.
- we offset the high cost by selling complete sets of templates to other fliers who were interested. In the end it cost us nothing! With EDM the thickness of the material being cut is irrelevant, thus it is possible to stack up many layers of steel to produce multiple copies of each template.
-it is also possible to have steel templates laser cut. But only single copies are possible (or just a few). Andriukov sells laser cut steel templates for example.
- I recently heard that there is a Hungarian source for steel templates (requires co-ordinates or CAD file) that is very reasonable (produced by Varadi for 20 Euros for a 6 piece set)..
- I arranged the templates so that the lower part of the cut could become a part of the sanding jig used to create the wing jig. Each airfoil section was rotated to the correct angle (using the bottom edge of the steel plate as reference) so that wash-out (or in) would be automatic.
- I glued a piece of high density foam (denser than Rohacell, the type used for prototype model making) to a section of Aluminum channel stock (aprox 2" deep x 6" wide by the length of the panel)
- the bottom cut-off of the steel templates were glued to the end of the foam with the bottom surface flat on the Alum channel.
- the undercamber was then sanded using a long, steel sanding bar (1/4" x 3/4" steel held vertical, edgewise)

The whole job went fairly quickly (several evenings). I vacuum bagged a layer of 0.010" soft aluminum to the top of the foam and then glued a layer of drafting mylar (with the plan plotted on the back side in reverse) using contact cement. This gave a very smooth and stable jig. I think that the aluminum surface might not be required though.

We drilled holes in the front edge of the channel at each rib location and press fit in a small finishing nail in each hole. These were used to loop 1/8" rubber strip across the wing to hold down the carbon strips. I use epoxy to glue my strips down.

To make the ribs fit perfectly to the spar and the D-box was pretty easy. I made each rib a little bit thicker than it needed to be, and glued the steel templates to the end of each panel. Then the panel was placed onto the jig using double sided tape. The wing ribs were then sanded using the steel templates and the long steel sanding bar until they were flush with the spar/D-box and the trailing edge. Simple!

Final step is to cap all the ribs.
I made an angled block that attached to the end of the jig so that I could sand the dihedral angles while the panels were still on the jigs.

Lot's of work I know, but it sure produced very nice wings at least as good as our Eastern European friends.

Tony

« Last Edit: March 04, 2010, 04:05:32 AM by tonymat » Logged
CHE
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« Reply #7 on: March 04, 2010, 09:18:57 AM »

tonymat,

Now look, interesting as your method is, this just isn't the British way of doing things and since I now know you're actually Welsh you should be aware that only jigs made from old floor boards ("I used to dream of makin' wing jigs from floor boards ....") and fish glue is acceptable practice.

CHE

PS A link to the Hungarian template makers would be useful though, er, but only for research purposes you understand.
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richard
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« Reply #8 on: March 04, 2010, 01:05:27 PM »

As I understand it the jigs are boards, with the negative impression of the underside of the wing milled into them.

I might be able to produce these on my cnc machine, maximum length 900mm.
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boffin
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« Reply #9 on: March 04, 2010, 06:40:47 PM »

Richard,

If you get coerced/side tracked into wing jigs..........yes please, one for me as well.
I do have a home built ply/balsa effort but it is organic and moves about dependent on temperature and humidity.

Regards Ian
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richard
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« Reply #10 on: March 04, 2010, 07:03:46 PM »

Does the surface need to be relitively soft for sticking pins in, or hard & non-porus. Also some pictures of the jigs & how they are used so I can get an idea.

Finally airfoil co-ordinates, planform & washout details will be needed.
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RobinB
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« Reply #11 on: March 04, 2010, 10:02:53 PM »

I cut building supports and cores from blue foam. I use a FeatherCut system with a 28" bow so effectively I can't do panels longer than 26" in one piece. Pins don't hold in foam too well, tho' it possible with a fairly low-cambered profile and a very shallow support to pin thru' to a hard balsa or hobbyboard base.
Usually the support/jig is covered with thin mylar or cellophane and the spars are taped to it, or the film is given a spritz of 3M 77 which holds components in place. If you want to use the jig several times it can be skinned with fibreglass.
The most time-consuming part of the process is making cutting templates. I make mine from 3mm phenolic aka Tufnol. These are cut on a table-mounted router using a pattern bit which is guided by a spruce or mahogany master profile.
It's useful to have the full profile cut as the top 'shell' can be used with weights to hold the panel true while  glue joints are setting. Some people like a spare piece of support cut to use for holding rib stacks during sanding. The core can be cut at various points along the panel to check the profile - very useful if you're building a tapered panel with different profiles at each end.
Robin
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tonymat
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« Reply #12 on: March 05, 2010, 03:15:08 AM »

Now look, interesting as your method is, this just isn't the British way of doing things and since I now know you're actually Welsh you should be aware that only jigs made from old floor boards ("I used to dream of makin' wing jigs from floor boards ....") and fish glue is acceptable practice.
CHE, well I was afraid of that! I'm afraid that we haven't been able to get decent fish glue for many years here, and just try and get crispy bacon like before the war! And the wood, don't get me started on the wood... But I digress.

If you need more info on the hungarian template maker, (no link I'm afraid) you'll have to send me an E-mail: tmathews1@sympatico.ca

The CNC cut jigs sound very interesting indeed! Well, to me, not to you I know. Not much call for fish glue in these parts lately, and where can a chap get good banana oil I ask you?

Tony
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tonymat
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« Reply #13 on: March 05, 2010, 04:37:26 AM »

Incidentally, I have seen quite a few hot-wire cut wing jigs in use and can say that they can be very good for composite wing construction. The ideal is CNC foam cutting as no templates are required. (fish glue optional of course for CHE).

Another option for D-box wing jigs is to actually go the minimalist route.  Take a flat board (in the UK old floor boards are the preferred choice naturally) and glue some 1/8" or 3/16" wide part-ribs (flat on the bottom and with the mirror image of the undercamber on top) at the required rib spacing. Each wing rib will then sit upon the jig part-ribs for support. Many people will build their D-boxes with a flat bottom so they can be assembled on a flat plate in advance. A quick and dirty method ideal for a one-off (or two).

Naturally, the glue of choice for attaching the part-ribs smells rather fishy... Wink

Tony
-enough with the fish glue already! Grin
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CHE
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« Reply #14 on: March 05, 2010, 09:12:07 AM »

Richard,

"As I understand it the jigs are boards, with the negative impression of the underside of the wing milled into them. I might be able to produce these on my cnc machine, maximum length 900mm."

Have you got a queue outside your door yet ?

The best jigs made for FF were by Joe Maxwell who used a blockboard base with Obeache covering which was shaped to form the lower surface section. Joe stopped making these as much because good quality wood wasn't available as much as he was well past retirement - sadly Joe died a few years back. I've heard of jigs being machined from thick MDF as well so there are some alternatives. I assume a 'dxf file or similar would be OK for coordinates ?

CHE
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