Drag and resistance can occur from overall wing size and the size of the leading edge. The flatter the profile ie high aspect compared to a low aspect wig, the greater the speed.i would think your 1650 is going to be faster overall.

Pacey said..
Drag is primarily made up of two component, parasitic drag and induced drag. Parasitic drag is proportional to the area of the wing and the square of the velocity. Foil section and angle of attack are also factors, but for the sake of argument you can assume these are constants.

induced drag is dependent on the square of the velocity, the aspect ratio and the lift coefficient, which itself is dependent on the angle of attack, which will be determined by the area of the wing.

so the net result is that at low speeds, total drag is dominated by induced drag, and at high speed, drag is dominated by wing area.as a general rule, for straight line performance you should aim to maximise wing span to minimise induced drag, then choose wing area based on the speed range you wish to operate in, large area wings for low speed efficiency, narrow chord wings for high speed flight.

Just what I was thinking.
Well sort of, skinny wings go fast.

Pacey said..
And for anyone that doubts the benefits of wingspan, this is where glider design gets to when wingspan is not constrained.

Note that gliders require both low speed performance for optimal climb in thermals, then high speed performance for travelling between thermals as efficiently as possible. So even with the low speed requirement, the wings still tend towards high aspect ratio


Similarly, this is a state of the art International Moth foil, and I think it shows that SUP/Windfoil/Wingfoil foils can still potentially go to higher aspect ratios for outright performance. However downsides might include loss of manoeuvrability and pitch stability, and while in some cases these can be reduced by other design factors such as anhedral, sweep, fuselage length and stabiliser area, high aspect ratio is not going to be ideal for everyone.

What is the size of the Moth wing?

Went through the same process with hang gliders years ago ......higher aspect / thinner profile faster wings with better glide ,but the compromise was not as easy to turn and twitcher to fly.
So we ended up with 3 basic types

1.training glider ( low aspect easy turning low stall speed )
2. intermediate glider ( mid aspect faster/ better glide/ still good turning )
3. Advanced glider ( High aspect fast/ great glide/ crap handling)

Can see the same pattern happening with foil wings.

Yep , I agree, with flying HA you trade a lot of handling and safety for a little bit of performance, and I suspect with foiling it will be the same.

container said.

How about 1.4 metre span, AR of around 14

Love the fact that you're giving it a go. Reckon straight line glide will be awesome. Please post again with a ride report.
Is it based on a Horten wing?
Does that also mean tail less?

Looks great Container! Did you shape it by hand or luck enough to know someone with a CNC machine? I'm shaping a 1.2m HA by hand out of Paulownia around 8.5 AR. Tricky with a tube mount compared with the Axis system but you get to keep the thickness down.

Cheers bois, it is designed on paper and shaped by hand, 80kg m/3 pvc foam. not directly based on a horten wing but it does use the same lift distribution concept, It looks similar as the axis mount constrains the size of the wing root so you end up with that big spikey bulge out the back.
I can neither confirm nor deny the existence of a tail wing

Relapse- you have to show us now! a square tube gofoil style mount should be exactly the same to build, the only extra step would be pre forming the tube

I kept the plan form simple to make getting the foil right easier. 3D printed the tip foils and glued then in place and printed a center template in two halves. Rough shaped with an electric planer then hand plane and finally an ordeal sander. Wood is quite stiff but still needs a layer of carbon for stiffness

The X 14/11. 14 is AR and 11 (deg.) is total amount of twist from root to tip. I know i know it looks ridiculous but its only a flat water test bed for mk. Deux

That looks insane , well done and keep us posted . Impressive build.

Pacey said..
Looks awesome. So are you going for a Prantl lift distribution? Are you also reducing the camber of the wing profile as it moves towards the tips?

Very interested in hearing how this goes, might be brilliant, might be a disaster

Cheers. Yeah agree with you there, either gonna be awesome or an expensive lesson. i spoke to al bowers, the nasa scientist who ran the study on the prandtl flying wing, he gave me a couple of numbers to use regarding wing twist and where exactly to put it.
I used a slightly cambered section (eppler195) out to where the lift becomes zero, then it changes to symmetrical to the tip. You can use either a highly camber or completely symmetrical foil out here, im wanting to maximise downforce so went with the latter. I would say the former will be more efficient on paper. The centre just is what it is to fit the axis mount in

My thinking here is the +9 degrees aoi in the centre will provide the lifting force necessary to keep foot position roughly the same, -2 degrees at the tips will provide downforce and positive pitching moment.

Now imagine if you will a yellow fin tuna or marlin tail laid flat, mast in the crux of tail and tips swept back 31 degrees so they are behind the mast and thus producing downforce behind your back foot position.... why was it you needed a tail wing again?

container said..
Now imagine if you will a yellow fin tuna or marlin tail laid flat, mast in the crux of tail and tips swept back 31 degrees so they are behind the mast and thus producing downforce behind your back foot position.... why was it you needed a tail wing again?

A planform something like a Horten wing?

Residing in Maui I see a lot people on all kinds of gear. Wingfoiling is Blowing Up! GoFoil appears to be most popular, followed closely by by Naish, Axis and Armstrong. I'm 165# / 76kg ...I switched to Armstrong 1550 /1200 from Axis, now I'm having fomo that Armstrong does not have a true HA foil. The guys on GoFoils GL 140 are on a relatively small wing and just blazing, early planing, better glide and excellent maneuverability . Am I missing something here? They are on 1000-1150 cm wing and I'm on a 1550 ... but they have far more efficiency? Is this my imagination and fomo or is it real? I've got foil brain...Someone in the know I was speaking with stated the whole industry will be going high aspect in due time...of course that's just an opinion... I was thinking of getting a GoFoil or Axis (Execellent Selection of foils) , but still keeping my Armstrong maybe dumping the 1550 and 1200 before they release their HA wings as I heard they will have some HA wings "someday" but it's nowhere soon it seems.. Thoughts? Comments?