Chris Foss Phase 6 build log - RC Groups
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Nov 11, 2009, 07:17 AM
Late for work again!
Gary Binnie's Avatar
Build Log

Chris Foss Phase 6 build log

Well it must be winter because I'm building again!!

Continuing in my quest to build anything that Chris Foss has ever designed I bring you the Phase 6!!

What is a Phase 6? It's a three channel slope soarer design dating from the late 1970s, one of two sloper kits still available from, the other one being the Middle Phase trainer. The current revision of the instructions is 1986.

It comes in two versions, 'Sport' with an Eppler 205 type wing and 'Professional' with a symmetrical airfoil. I have gone for the sport version.

I've wanted one of these for a while and I finally cracked yesterday!

This build log will be brought to you by Breakfast Bar Model Productions Ltd!!

Last edited by Gary Binnie; Nov 12, 2009 at 05:42 PM. Reason: Change a word
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Nov 11, 2009, 07:47 AM
Late for work again!
Gary Binnie's Avatar

So what's in the box then?

I was told that this particular kit is about a year old, I had a quick look in the shop to make sure that everything was ok.

What's in the box then?

You get two white foam veneered wing panels, pre-cut ply fuselage sides, pre-cut tailplane, fin and rudder and stripwood.

This is the first Foss kit that I've seen with Liteply parts, not many, just some die-cut wing seat doublers. All the wood is good quality which I would expect.

There is a hardware pack, with aileron torque rods, dowels and nylon wing bolts, closed loop trace etc. White plastic 'snap' links are provided but I will use my own metal links when it comes to it.

Paperwork is limited to nine pages of A4 clear instructions that include an illustrated parts list, there is no plan.

Sundry parts include a length of fibreglass wing bandage and a stick-on letter sheet.
Nov 11, 2009, 08:01 AM
Late for work again!
Gary Binnie's Avatar

Where to start?

The instructions suggest starting on the wing construction. I am having a think about a four servo wing, a standard build would use one central aileron servo driving torque rods. An option given in the instructions is a three servo wing, where the same central servo drives two flaps together (for elevator/flap coupling) with two separate servos for the ailerons.

A friend had a Phase 6 and I remember that when his wing popped off on a slightly lumpy landing the aileron torque rods came out through the fuselage sides. Will have a think about all this later.

That leaves the fuselage as a good place to start, again I have read that there is a possible problem with weakness just behind the wing seat.

Pass the building board!

Nov 11, 2009, 09:07 AM
Phil.Taylor's Avatar
Definitely go with at least 2x wing servos for spoilerons etc. - 4x for crow better still, but couple the flaps to the ailerons for good roll. Don't skimp on glassing the fus, at least the front & for a way behind the wing - known weak spot is the fus at the rear of the wing.
I had a "Sport" version & also tried a symmetrical wing - the sport flies much better, and a bit of reflex flaperon improves inverted/outside moves.
Do a search on here & on RCMF & you'll trawl up other P6 stuff.
Good luck with the build.

Nov 11, 2009, 09:58 AM
Late for work again!
Gary Binnie's Avatar
Cheers Phil, I have searched and found some other P6 stuff that has given me ideas. I would like to go for the four servo wing but it's going to involve some surgery!!

Was planning to glass inside and outside of the fuse nose and possibly the whole thing but I'm not sure what that will do for the weight. I rarely fly in howling gales so it's a balance between strength and weight I suppose.

Fairly sure that my radio can cope with the four servo wing but I'm not sure if I can cope with the programming!! We''ll see.

Front and rear fuselage sides are joined, this is all strangely familiar, I appreciate all the parts being ready cut though, the slow bit of scratch building!


Last edited by Gary Binnie; Nov 11, 2009 at 05:44 PM. Reason: Typo
Nov 11, 2009, 05:41 PM
Late for work again!
Gary Binnie's Avatar

Today's toil

After about eight hours I have two fuselage sides almost complete.

The worst part was trying to bend the 3/8 hardwood triangle stock and glue it at the same time, I put saw cuts in per the instructions but they didn't seem to help much, got there in the end anyway.

Still to add the joiner reinforcement plates and wing seats, CF shows 1/32 ply joiner reinforcements, think I will double that thickness.

Pictures tell the story so far.


Nov 12, 2009, 04:43 AM
Registered User
I built 3 sixers and made a mistake on the 3rd one. Those lovely joints for the fuz sides look as though they can only go in one position. Not true.

CF asks you to run a piece of string from the nose centre , through the joint back to a point he specifies at the rear end.

I didn't and had to pack the TE of the wing to get the relative incidences right. I guess you could't change it now it's glued but worth double checking in case you overlooked this like I did!

I glassed the whole fuz and wing and the little extra weight was not a problem. Yours looks like the Sport version and it will fly in light lift.
Nov 12, 2009, 07:48 AM
Late for work again!
Gary Binnie's Avatar
Hi Guy, Yes CF says to draw a datum line from nose to tail, you can see it in the photos. The former uprights are 90 degrees to this line as well. Maybe the instructions are clearer now, I almost added glue to the part where the angled wing ramp sits though.

Yes, I went for the sport version, read that the 'pro' version needs plenty of wind.

Better do some more.


Nov 12, 2009, 10:36 AM
Registered User
I have both versions. The Pro does need strong lift and I much prefer the sport version as it will do everything the pro does except hands off inverted.
The datum line bit was easily overlooked in my instructions some 20 years ago!

As someone said above the weak point is behind the wing and I would do all possible to strenthen it around the wing seat internally.
It might be a bit dated now, maybe but in it's day it was one of the best aerobatic planes around. I really must repair mine!
Nov 13, 2009, 12:46 PM
Registered User
Synergy1's Avatar
will be following this as im thinking of getting one
Nov 13, 2009, 01:13 PM
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Gary Binnie's Avatar
Ok, I hope my thread helps you decide, there are some other P6 builds on here but not to the level I go into perhaps. I partly do it for my own record and also to help others (and to get some advice myself as well!!).

Should be an update soon.

Nov 13, 2009, 02:22 PM
Late for work again!
Gary Binnie's Avatar

More plodding on

More progress on the fuselage today and a little bit on the tail feathers.

Still having a think about the four servo wing option, not keen on cutting holes in it at the moment.

Nov 13, 2009, 04:59 PM
Registered User
sand it round - make sure the fins square - sand it some more
Nov 13, 2009, 05:06 PM
Late for work again!
Gary Binnie's Avatar
I can't sand it properly until I've fitted the top front sheeting, the fin was just added for effect/trial fit and has obviously not been sanded to section, fully aware that it will need lots of sanding when the construction is finished.



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