Phase 5 by Chris Foss

After many years of procrastinating I'm finally building a Phase 5. Designed in 1978 this model is often considered to be Chris Foss's (CF) best slope model. It was never available as a kit so the only way to get one is to build it yourself. CF is still selling the plans if you fancy one. The red model is not mine, this is another example of the Phase 5 in case you're not familiar with what I'm planning to build.

The Phase 5 plan calls for a built up wing but I'm deviating from the plan and making one from foam with a balsa skin. A snow day today meant I could make a start. CF does not specify what sections are used for the root or the tip so a bit of guesswork and internet trawling resulted in the semi-symmetrical E374 for the root, modified a little to make it thinner. The tip is fully symmetrical and is between NACA 0010 and 0011. It's actually 10.67% thick so maybe it's NACA 0010.67?
Images show both left and right wing cores cut from the same block of foam, the semi-symmetrical root section and the symmetrical tip section.

Those cores look very nice Mike, you've got your hot wire cutting down to a fine art

Chris001 wrote: Those cores look very nice Mike, you've got your hot wire cutting down to a fine art

Yes they do. I think Mike could do a little business on the side and make cores for us lesser mortals with no more engineering tools than a bottle of Cyano.:lol:

I'll follow this project / subscibe with interest as I still have to make a start on my Phase 6.

Mike - Looking good so far.
Just one question - since it was designed with a built up wing - do the wing ribs give you
the required wing section ?

Colin.

p.s Welcome home Phil.

PhilF51 wrote: I think Mike could do a little business on the side and make cores for us lesser mortals with no more engineering tools than a bottle of Cyano

The final cut is quick, but there's loads of time preparing the templates and cutting blocks of foam to the right size in the first place. So it's a labour of love really.

PhilF51 wrote: I still have to make a start on my Phase 6.

Can you check whether CF uses a spar or dihedral brace on the wing at all? My guess is that it is just foam and obechi veneer and that once joined you reinforce the join with a glass bandage. This is what I'm planning to do but would modify my ideas and add a spar and/or brace if this is what CF does with the '6.