Topic: Wing Section advice - Phase Lift

Hello everyone

I am planning to build a Chris foss Phase Lift. A lovely looking model and plenty of woodwork to enjoy!  However, Chris advises to modify the section from flat bottom...

I would be interested in any comments/experiences on airfoil sections. I have donwloaded Profili, which looks great (and easier than using the sandwich method) but have no experience in choosing the right section.

The model will be mostly flown off the slope, so requires a good speed range but good lift potential.

Any commnets welcome please (also any tips on Profili!)

Regards

Ian
 

I've just done a Phase 5, and that is an Eppler 374 section..The difference being it goes to fully symetrical at the tip..but if you do the section full span I can't see you having any problems.  You may need to build it off the plan though too get the under camber in the correct place. Selig 7012 is a good section too..That is on the Simprop Saggita (2.2 metre) and can really go when you want it to, and slow down to walking pace for landing. 

Tks Steve - I'll consider those. I think Eppler 374 was used by Stan Yeo a lot on his models. Strangely, Prolifi does't list the 374 (although the 375 looks similar).

Take a look at MH 32 or MH30 for even more penetration. Although slightl undercambered, can be built on a flat board, also work well with flaps. I used them on the "Watts Up" electric soarer.

One bonus is that with modern radios you do not have to have that linkage arrangement on the Phase Lift for the flaperons that it had.

Mh32 seems sensible. Used on a lot of glider models.

another vote for the MH32 over here....so long as the wings don't end up too floppy (I'm guessing the original section isn't as thin as the '32)

Tks for those guys - the plan hasn't yet arrived so I wil lcheck the thicknesses when it does. The MH42 looks a little thicker - they look like good sections.

My Phase Lift is 20+ years old. I removed the mechanical
mixers/linkages and did it all on the Tx, as you'd expect, a couple of years ago.

For a new build I'd put the servos in the wing.

A real 'dislike'! The wing bends summit b-awful with the piano wire joiners at the fuz end and at the tip end. Structurally fine but aaahh

Figure out how you can use the maximum diameter CF rod to hold the bits together!

She does fly fine though, even with a flat bum wing.

My 5m vortex uses an mh32. Its a real puppy until you put tje nose down and zip when the wind picks up. Then it really starts to be fun.
I'd vote for mh32.

Thanks again - and noted the comments about the weak wing joiners - I don't want it looking like a CMPro Discus (with flappy wings)

Ian

I was thinking phase lift with MH32, but loose the polyhedral and have 3degrees of dihedral in the joiner.
That would mean building a two piece wing, so each half would be approx 1.5 metes in length with a tapered spar.

I have a phase lift plan. Would be interested to see how it works with mh32. Mh32 responds extremely well to launch flap and speed flap. 2mm of down droop and it goes up(fast). Forget the flat bottomed sections. Regarding the joiners. How about 2 10mm carbon joiners through the plane, with carbon alongside ply along the first 1/3 of the inner wing.

The calypso cobra is MH32 and its the best launching F3B model I have seen.

I have enquired about some foam MH32 cores from foam wings and it would be cheaper to buy a second hand mouldie.
So I will have to resort to hand crafting some ribs, so check my phase lift build in around 40 years. lol

The calypso cobra is MH32 and its the best launching F3B model I have seen.

I have enquired about some foam MH32 cores from foam wings and it would be cheaper to buy a second hand mouldie.
So I will have to resort to hand crafting some ribs, so check my phase lift build in around 40 years. lol

Wont thermal like a phase lift with mh32 tho. U could look for a 2nd hand tangent plane. They use nice sections. Prolly cost you same as a 2nd hand mouldie. And fly the dogs. Thermally good, aerobatic and quick when you want.

 

I have enough mouldies for speed.
I want to build something, so mark one will probably be to the plan.
I havent even bought any wood yet though :(

I have enough mouldies for speed.
I want to build something, so mark one will probably be to the plan.
I havent even bought any wood yet though :(

I have enough wood for a P5. Never got round to building it tho..

Balsa wings are fairly easy to make using the sandwich method. Just get your templates etc. you could quite easily change the section. And it would probably be a big improvement.

My Phase Lift is 20+ years old. I removed the mechanical
mixers/linkages and did it all on the Tx, as you'd expect, a couple of years ago.

For a new build I'd put the servos in the wing.

A real 'dislike'! The wing bends summit b-awful with the piano wire joiners at the fuz end and at the tip end. Structurally fine but aaahh

Figure out how you can use the maximum diameter CF rod to hold the bits together!

She does fly fine though, even with a flat bum wing.

I remember when the Phase Lift was the rage in the 70's if you got it flying fast, so as the wing pitched into a negative incidence angle, it could pitch down violently & suddenly. All the flat bottom sections will do this and washout makes the tips go first, causing the wing to bend alarmingly

Whilst carbon joiners are good, they do not give(bend) so you get no warning when they give up. I would be wary over using them on a wing joiner into the fuselage as the load is not to be ignored. I use them on wing joiners where they plug into a one piece centre section, as the load decreases dramatically at 50% of the semi span.

The loss over performance in thermal mode, with MH 32 would be very minimal over the flat bottom, but the all round performance would be superior.
Another section that would work well from close to the period is Eppler 392, pretty sure this was used on the "Eliminator" or a mod of it.

Flat bottom section are very unaerodynamic. Every flat bottomed I've flown is rubbish in comparison to modern sections.

Since we are now 2011, and the cost of putting something like this into tje air is probably in the coupla hundred quid mark for the wood/covering/install I would try to build the best I could. For me that wouldn't be a flat bottomed section.

Sound advice - thanks guys. That's given me a couple of good sections to look at and also some thought about the wing joiner...

Also, regarding cutting th eribs, if you download Prolifi it should do the trick. A license is 15Euros and you can select froma wide range os sections. It will makrk out spars, LE, TE etc and plot all ribs based on interpolation from the root to tip ribs.

Should be better than sandwiching them.

You've given me inspiration to make my phase lift with mh32. Once my asw 20 is finished, it can be my winter project.

Here is my 20+ year old PL!

phase lift looks very nice.

+1

it reminds me of my beloved Miniphase

I have run off some plots from profili for some ribs in MH32 @ 8%ish to fit a phase lift.
The tapered spar is going to be a work of art in itself.
I'm temped to get the profili licence and ask light work to bash out a rib set for me.

Here is my 20+ year old PL!

Would look nice with my P5.... 

I was incredibly lucky. When I picked up my plan from CF he had one set of pre-cut ribs available and I had 'em in a flash! Flat bum profile though....

You shouldn't change too much, to bring the plane up to date but you might consider slimming the fuselage a tad. Servos were big in those days!

I have run off some plots from profili for some ribs in MH32 @ 8%ish to fit a phase lift.
The tapered spar is going to be a work of art in itself.
I'm temped to get the profili licence and ask light work to bash out a rib set for me.

From that pic you could improve the wing look by making the inner panel wider in IMO. Give it lighter loading for better thermals. They look a little skinny. What you gonna do with the joiners? I still thing carbon in brass tube. Could even move the wing to top of tje fuze. Then it would like like a big P5/PL cross. Certainly he unique.

I was going to try and keep the PL form as is, and not mess up too much the fosse lines.
The joiner I havent thought about yet, apart from a large diameter piano wire rod.
I want 3degrees of dihedral and a straight 2 piece wing.
J

Mh32 likes a wider aspect ratio. Could go up a bit and improve performance. Full length flaps/ailerons too.

From that pic you could improve the wing look by making the inner panel wider in IMO. Give it lighter loading for better thermals. They look a little skinny. What you gonna do with the joiners? I still thing carbon in brass tube. Could even move the wing to top of tje fuze. Then it would like like a big P5/PL cross. Certainly he unique.

Some would say that was sacrilege..

Some would say that was sacrilege..

Nah, itd look great and be one of a kind. Phase Custom.

I have enough mouldies for speed.
I want to build something, so mark one will probably be to the plan.
I havent even bought any wood yet though :(

not bidding on this then Jon?

http://www.ebay.co.uk/itm/CHRIS-FOSS-PHASE-LIFT-SLOPE-SOARER-GLIDER-AEROPLANES-/380382615889?pt=UK_ToysGames_RadioControlled_JN&hash=item5890921951

More interesting stuff - nice photo Marcellus - inspiring! She looks lovely!
 
I'm still waiting for the plan - will probably go for 2 piece wing but not sure whether to lose the polyhedral or not - may be easer to have  a flat centre section with fixed tips with a little dihedral perhaps?

I'd probably go for a stell joiner - maybe even flat blade and box section - I used that on my P5.

MH 32 is sounding the favourite on here, but I'll look at the thickness of Chri's design.

Can't wait to get building! It'll probably take me years!

I have a plan , but havent ordered any wood yet.
May get light work to laser etch the parts, which would save some time.
J

It goes without saying, that the purchase of wood and other materials makes a photo accompanied build log mandatory...

Years? You need to lock yourself in the shed and get the job done!

Couple of hours in an evening an it could be done in a couple of months  watching with interest...will it be a build thread?

Spoons - who are 'light work'? I considered getting CND cut parts but understood they can't do it from plan but need a CAD file of some sort?

I'm probably using the Olde Worlde techniques (plus a phtocopier)