Chris Foss Phase Lift - RC Groups
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Apr 01, 2010, 11:53 AM
Late for work again!
Gary Binnie's Avatar

Chris Foss Phase Lift

Hi folks,

Continuing my quest to build or own all of Chris Foss's glider designs I bring you the Phase Lift!!!

I had been watching this 'unnamed glider' on eBay and was fairly sure it was a Phase Lift from the photos so I bid on it and happily won it yesterday. Picked it up this morning and have just been having a good look at it.

What's a Phase Lift?!! Don't know much about it myself, there are photos of two different models with Chris in 'Radio Control Soaring' and 'Radio Control Thermal Soaring', the older of the two books is from 1974. In one photo it has spoilers, in the other it does not.

Basically it is a 130" span, all wooden construction thermal soarer. The tailplane is all-moving and the wings are split into four panels (I read that it can be flown as a sloper without the tip panels!!).

The intriguing part is the 'trimmable trailing edge', it has full span flaperons that I believe were intended to be driven by an aileron servo fitted on a sliding plate that could be moved by a flap servo, a basic mechanical mixer. At the moment the flaperon cables are connected to the rudder servo (novel!).

Looking round the model that I have just bought I don't think it will ever fly again as there are too many problems with it (although they could be overcome).

I wrote to Chris a couple of weeks ago about this design and others, the good news (and very spooky as he just rang to reply while I was typing this, no word of a lie!!!) is that the plans are available so I will have one on the way very shortly.

Some photos.

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Apr 22, 2010, 05:16 PM
Late for work again!
Gary Binnie's Avatar

More information

I received a newly printed plan and a set of build notes from Chris today, nice to learn more about it.

Dates from about 1974 with several revisions to the plan, last one in 1978.

There are options for short/long tip panels for 127" and 151" span and plug in wing tip blocks to fly it as a sloper on the inner panels only (75" span).

The prototype 127" version weighed 3 1/4 lb for a wing loading of 8 1/2 oz/sq.ft.

The pre-computer radio aileron/rudder mix linkage is cunning! It can be built without ailerons/flaps using increased dihedral.

Will be a while before I can even think about building one but it's nice to have the plan and notes for when I get the urge.


Jun 13, 2012, 08:34 AM

Phase Lift Progress?

Bringing up an old topic......
I read with interest the beginning of your Phase Lift adventure; how did it all pan out over time?

I have had a lot of PL experience in the mid to late '70s - my father and I built a few and developed the designs further. We also had several fly-offs against Chris and Rick shaw who was taking an alternative low aspect ratio approach at that time; his designs could compete over a huge range of operating conditions, from flat calm to strong winds.
But nothing could beat a good pilot with a well built Phase Lift for pure thermal soaring. Tricky to manoeuvre near the ground but serious Aerobatics possible (with the shorter tips) if you have enough altitude.

So - how did it go? Did you build a new one? Did you find the time to learn how to fly it well? (a bit like golf, you have to learn the skills....)

Andrew B.
Jun 13, 2012, 10:19 AM
Late for work again!
Gary Binnie's Avatar
Hi Andrew, always nice to hear from other owners.

Sadly this Phase-Lift remains in the loft unflown. It could be flown but there are numerous problems that would need a burst of enthusiasm to get round!

I have the plans and fully intend to build a new one when I get time. Just last week I obtained a Multi-Phase 100 short kit and plans, another one for the building board queue!

To tell the truth I have some modern F3J mouldies now and am competing in the BMFA league this year but I still have a soft spot for the older designs, I just enjoy building them.

There was a PL on eBay recently, don't know how much it went for.


Jun 13, 2012, 11:25 AM
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prodjx's Avatar
Great to here from you Gary.BTW if you go to last month's Green's Peak under Alert you'll be able to see the 100 or so photo's I took while there. There's also a 10min. video on entitled Alpine Ultrabatics. I've been busy making mold's, like a 1/6th scale cowling for an H-1 Hughes racer, also did a sort of Le Fish mold too. Later Dave.
Jun 13, 2012, 05:04 PM
Late for work again!
Gary Binnie's Avatar
Yep, I'm still about!!

Seem to be very short of spare time this year. They say it's even worse when you're retired!!

Jun 13, 2012, 10:35 PM
Registered User
prodjx's Avatar
Ooh, that hurt. Today I sorted out the stab system and will install the rudder post tomorrow on my Le Fish. Then I want to get the wing carry through tube straight with the stab. Today I also laid up a carbon canopy for it. Till next time , Dave.
May 05, 2016, 05:25 PM
Registered User

Another PhaseLift

just found your original thread on the PhaseLift
built mine in about 1980 with the old mechnical mixer ~ flew like a dream but very difficult to get it down (it flew too well !).
just dug it out of the attic and started to convert it to 2.4Ghz and computerised radio with a 4 servo wing.
will have to re hinge the flaps to get more "down" deflection for CROW braking (so I can get it down this time !).

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