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Old Mar 03, 2009, 08:49 PM
Late for work again!
Gary Binnie's Avatar
Northampton, England
Joined May 2004
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Build Log
Chris Foss Multi Phase

Hello folks,

I have started this thread as a build log as that is the intention!

I won a plan on eBay recently of the Chris Foss Multi Phase, a mid 1980's 142" span RES thermal soarer, and am very keen to build one.

The plan is quite good and I have some building notes and a couple of photographs but not much more than that at the moment.

I am hoping that a wing core supplier will get back to me as I would prefer to build it as it was designed and I don't have the facility to make the wings myself (or the skill probably!)

It strikes me as a simple design with the potential for good performance, I have written to Chris in the hope that he can help with the wings and any other advice that he might have.

Cheers

Gary
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Old Mar 03, 2009, 10:12 PM
ein flugel schplinterizer
seanpcola's Avatar
USA, FL, Pensacola
Joined Sep 2004
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Beautiful lines. Was the original type wing built up?
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Old Mar 04, 2009, 06:27 AM
Late for work again!
Gary Binnie's Avatar
Northampton, England
Joined May 2004
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Hi Sean,

Yes, I particularly like the tail, the fin and rudder are very tall.

The original design is for white foam veneered panels, the inner panels have a 1/4 x 1/4 full length spruce spar laid in at 1/3 chord with an 1/8 x 1/4 strip laid in slightly further back, you might just be able to see them in the photo above.

The outer panels use a 1/32 ply dihedral brace at the join which seems a bit thin to me but Chris know best!

It would be possible to use a built up wing but I would like to try to get hold of some cores (lazy!!).

Wing area is 1074 sq in (7.45 sq ft) with a wing loading of 8-9 oz sq ft. (which if my calculations are right gives a finished weight of 4 lb 3 oz).

Have added a photo for scale, I believe that this is Chris holding the model.

Cheers

Gary
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Last edited by Gary Binnie; Mar 04, 2009 at 09:42 PM. Reason: Add weight calculation
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Old Mar 04, 2009, 09:32 PM
Late for work again!
Gary Binnie's Avatar
Northampton, England
Joined May 2004
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Just a little update, the foam wing company have replied and we discussed options which included leaving off the 1/4 x 1" trailing edge stock with the veneer extending to the trailing edge, a much neater solution that I hadn't thought of.

With confidence that the wing panels will be on their way soon I can make a start on the fuselage and tail parts.

Not quite sure how this is going to turn out with nothing in my hands at the moment except a plan but I'm going to give it my best shot.

Cheers

Gary
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Old Mar 04, 2009, 09:44 PM
ein flugel schplinterizer
seanpcola's Avatar
USA, FL, Pensacola
Joined Sep 2004
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I'm watching Gary. Really interesting design and we know you can pull it off. You'll probably find several things to update along the way.

Sounds like a good idea on the TE. May I suggest something? Since you will extend the sheeting all the way to the TE consider laminating .007 or .014 x 1/4" CF uni at the juncture of the top and bottom. That will really help insure a ripple free edge. Plus you can use the TE for slicing apples, tomatoes and such while at the field.

Still think it's a sweet looking layout.

Sean
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Old Mar 04, 2009, 10:16 PM
Late for work again!
Gary Binnie's Avatar
Northampton, England
Joined May 2004
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I suspect the wing builder will do something like that, will ask him if I will be able to cut tomatoes with it!

Of the three 100S wooden gliders I have built the trailing edges were left fairly fat after sanding and I wondered about the effect on performance, not that I am after that as a sport flyer. It certainly contrasts with a fun fly twin jobbie that I built which has 1/4 square trailing edges (they say it reduces flutter).

Thanks for the encouragement, I might need it later! I'm not intending to update the design much unless it's something obvious, the elevator control rod is an aluminium tube, carbon might be lighter.

Forgot to mention that I ordered a fuselage building jig today, I have had trouble before with bent and twisted tail ends and this one is quite long and slender, will need extra care to keep it straight.

Posting the only photo I found of a Multi Phase on the net for inspiration, either he's short or this thing is big!!

Gary
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Old Mar 04, 2009, 10:28 PM
ein flugel schplinterizer
seanpcola's Avatar
USA, FL, Pensacola
Joined Sep 2004
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Gary,

If your builder is doing the sheeting too then the CF inlay should be no problem. You want the TEs fairly sharp. Blunt works for power stuff but flutter should not be an issue with this bird.

I don't think the gent in the last photo is particularly short. You just have a lot of wing in your future!
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Old Mar 04, 2009, 10:54 PM
Late for work again!
Gary Binnie's Avatar
Northampton, England
Joined May 2004
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I think he's about 5' 8", I am 5' 10" so I should just be touching the fuselage in the same picture. Will recreate it at the end for fun.

Hope I've got some wood lying about, suspect I haven't got enough of the right stuff though.

A materials list would be a logical step, will post it here and with the wing builder having the file it should not be difficult to make more of these.

I blame it on my dad for buying me a KeilKraft Comet (chuck glider)!

Gary
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Old Mar 05, 2009, 04:00 PM
SB-28 UK Display Pilot
GeeW's Avatar
ENGLAND
Joined Jul 2001
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Gary
Are we allowed to take a guess at the colour scheme on this one?
It's certainly an elegant looking beastie. Subscibed.

Gordon
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Old Mar 05, 2009, 04:06 PM
Say when.....
quigley257's Avatar
United States, MO, Hillsboro
Joined Sep 2005
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Very elegant looking ship!!
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Old Mar 05, 2009, 04:38 PM
SB-28 UK Display Pilot
GeeW's Avatar
ENGLAND
Joined Jul 2001
2,469 Posts
Gary
Is your foam cutter person available for other people? If so could you either post it up or PM me please nicely as I have an urgent need of a set of foam wings.
Thanks

Gordon
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Old Mar 05, 2009, 06:39 PM
Late for work again!
Gary Binnie's Avatar
Northampton, England
Joined May 2004
1,901 Posts
Hi Gordon, you could guess the colour and you might be right!!

http://www.foamwings.co.uk/Pages/Site/Default.asp is the site for the wings, very helpful.

I'd like to get on with this but life is getting in the way as usual, hope to cut some wood this weekend.

Cheers

Gary
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Old Mar 05, 2009, 09:52 PM
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Gary Binnie's Avatar
Northampton, England
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After much double checking of wing dimensions (Imperial to metric conversions) and finalising options I think the wings are good to be made.

Have compiled a rough materials list, most of the quantities are an overestimate, better to have too much than not enough!

Gary
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Old Mar 07, 2009, 06:35 PM
Late for work again!
Gary Binnie's Avatar
Northampton, England
Joined May 2004
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Cutting wood!

The fuselage building jig arrived but I could not get a base board for it as all the hardware shops are closed on Saturday around here, does this only happen in England?!!

Will do a mini build thread on it for free when I get the board.

I should start by saying what you get in the box....erm...nothing, just a plan!!

Paid a visit today to my LHS to get some wood, didn't have everything that I wanted and paid more for it than from a wood supplier but I like to support them. Shame I'm not into trains, looks like they've got everything for 'chuffer fans' to me.

I started by marking out and cutting the 1/16 ply fuselage sides, just used carbon paper. The plan says to cut it up to align the rear parts but there's no need to do that. The rear sides have straight edges so they can be cut with a steel straight edge and a sharp knife, takes a while but the result is good.

Front fuselage sides will need cutting on the scroll saw tomorrow. Once they are done and joined to the rear sections I will sand the edges so that they are identical.

Rudder next, 3/8 soft balsa sheet, couple of razor saw cuts, done! There is potential for lightening holes in this or even a built up structure. I usually make the mistake of chamfering the leading edge (for range of movement) before cutting the hinge slots so I'm going to leave it square for the moment.

Fin box, 1/16th sheet with 3/8 x 1/2 leading and trailing edges. There will be an inner structure of 1/8 x 1/4 strip. The lower sheeting is 1/16 ply for the stab bellcrank housing, I'm thinking about aluminium bushes for the stab hinge as it could be a 'wobbly' area.

More tomorrow hopefully

Cheers

Gary
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Old Mar 07, 2009, 07:48 PM
Registered User
S. FL
Joined Jan 2007
859 Posts
For us North Americans, back in the 70's and into the 80's Chris Foss was to rc soaring in the UK, what Bob Dodgson was to rc soaring in the USA. Beautiful innovative designs way ahead of their time
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