Foiling Trailer sailer

Rasputin22

Rasputin22
13,890
3,450
I think that Wortmann foil is the section that my sailplane uses. Works pretty good in the air but has been underwater too!

 

JulianB

Super Anarchist
1,161
1,549
Sydney mostly
I also have my wings (inc Glider, though I have not flown for 30 years) and I also have a father who was a highly decorated pilot who had a passion for aerodynamics and won some really impressive World Records in model-aeronautics that stood for 20+ years  (think 7 1/1 hours aloft in 1954, certianly pre-me).

But the thing that Dad really did teach me is nothing beats emperical testing, or to put it another way, Theory has to equal Fact and way too many people try to get Fact to equal Theory.

And what is going to happen is you will very shortly find out is the Theory = the Fact, and you will have a 1st hand oppotunity to add to the genral knowledge pool.

What you have done may well be absoutly perfcet for what you are trying to acheive, and all power to you, and I look forward to hearing about what you have done and acheived in these pages over the comming months and years.

What we found back in 2010 approx, was take the hollow out of the TE and drag droped considerably, lift did not diminish and when Dad and Bora (Gulari) compared notes that the non hollow TE foil (49er) generated high CoL and lower CoD's than Bora's hollowed out TE moth foils.    14 months later Dad was no longer with us and it is only now that the foilng and I am not going to say 49er because that will cause a shit-storm, so Bat-Boat, concept is raising it ugly head again.   I personally think a 49er at 25-28knts down hill is fast enough, and that foiling would probably slow it down, in terms of around course speed.    But I still have that now 10 year old lifting foil that was loving hand shaped by Dad, outside, & yes it was a canard configuration, and we as a community have a long way to go.

 
Julian I agree that you can't argue against  real testing at full scale but I think we are looking at two rather different scenarios .Depending  upon which part of Bora's moth foil you were testing against   As you have pointed out a 49er daggerboard is mostly working at  very low angles of attack except coming out of a tack hence your sizing equation. moreover it has to work equally well on both tacks. My lifting foil on the leeboard is rather different  and it has a large flap 30%  mostly to  radically reduce lift and prevent crashes otherwise a 17% flap would have much less drag . I have tested the need for the large flap on my moths  with the crashing result .

Said leeboard lifting foil is   going to be  right at or above the upper end of the low drag bucket with 3-5 degrees of angle of incidence  and 10degrees of flap  when foil stabilizing and going at 6-14 kts. Only when ? if I achieve  lift out will the  AOA drop down to 1-2 degrees or less with zero or negative  flap . This is analogous to a glider termalling versus  going for speed between thermal at best L to D . My Reynolds numbers will be 710,000 to 1.6 million which is pretty close to a std class glider . My understanding of  bernoulis principle and Epplers work in the low turbulence  wind tunnel in stuttgart is that it is desirable to place a hollow in the trailing part of the foil at the hinge of the flap to create a change in velocity /acceleration which reduces  laminar separation bubble  at the low end of the speed / Reynolds  range and  turbulent separation. when getting up to 2 million.  I may not be correct but I do note that the last americas cup boats were all using similar  foil sections  as best could be discerned  from photos and Basilicus  x foil modelling albeit it slightly thinner in thickness at 11 % .

I should add my verticals whilst close to Eppler 836 really have little or no hollow in the trailing 1/3 of the foil

Interesting you bring up the canard 49er . When I heard that you had done that I built a foiling moth with a bow rudder  full flying  forward canard  Wand on the bow rudder  and  a fixed main foil well aft of the usual position .2 problems with no jib  a stalled main has CoL at 50% chord huge weather helm   versus 25 % chord when sailing  Needed a reposition of mast step and add a stern rudder to get up flying .Then the problem was over powering the 60126 full flying front foil with any  power ,trim change . Ie not stable in pitch despite  a longish lever 2 +m in front of main foil. Could have changed to a symmetric  larger front foil but felt it was more trouble than it was worth.  So how did you solve those problems?? I know you found trapezing difficult presumably due to acceleration , fore aft trim changes plus the superman flights that do get you away from a crashing boat .

 

JulianB

Super Anarchist
1,161
1,549
Sydney mostly
Go look at



August 2009, I'm talking about the main lifting H foil under the center of the hull, max speed on another day was 28.5knts (I was crew, Harry was steering).

I'm talking about lifting foils, not lateral foils.

Anyway, every thing your talking about is Aero, your about to live in the Hydro world and non compressible is a bitch, I wish you well!

 
Thanks for the video. I presume you were then comparing with Bora’s Mach 2 mainfoil. How did you fill in the groove at the flexible hinge point to make it equally as fair as your one piece foil and what angle did you fix the flap at? I am not trying to be picky but these are major  issues when comparing foils in a wind tunnel.

 

JulianB

Super Anarchist
1,161
1,549
Sydney mostly
The beauty of Canard conf is that the main aft "lifting" foil follows the fwd "control" foil implicitly, so you don't need a hinge, you just lower the whole AoA when you get too high or increase it as you get too low.     The fwd "control" foil is so lightly loaded that you make it all flying, simply axel and rotate the whole thing.    The one on that 49er was 200mm total span, and 120mm cord with a 6% section and you can see the wand system, next time, we will go electronic, we did it on a moth with the progam on a smart phone in a RIB 100m away, all by BlueTooth.    Very tempted to "duck" the sailor, but we refrained.     That was also late 2000's.    Just used the ultra sonics that are now on the back of cars and do that beep beep sound when you get too close, worked a treat!

Very aware of "hinge" drag, 17-25% increase in air, probably double that in water.    (Why Boeings have that inner aireron)

We have had considerable success with a all moving TE of a lateral fin in sports boats, I plan to do another next year once mine has settle down.    Possibly use the same system in a hyrdofoil system very shortly on a support craft for training (sailing) boats.

 

Sidecar

…………………………
3,115
1,487
Tasmania
@JulianB, was the canard T (horizontal) foil asymmetric section, or symmetric and relying on AoA only for lift?

Presumably more consistent and predictable balancing as a symmetrical section?

 
Last edited by a moderator:

JulianB

Super Anarchist
1,161
1,549
Sydney mostly
@JulianB, was the T (horizontal) foil asymmetric section, or symmetric and relying on AoA only for lift?

Presumably more consistent and predictable balancing as a symmetrical section?


Asymmetric, probably a 3% lower surface and a 6-7-8% upper surface, it was a H foil, the 2 lee-board 100% endplated the foil and maybe that's how we got such great CoL's.   The lee-boards extended 150-200mm down past the Lifting foil. I thick we found that running it at 2.5-3° AoA was optimum but obviously on takeoff it would have been 6-7° and at 28knts it was probably nominally negative.    Just went looking for it, but my front yard at the moment is atroucious, suprised Deidre lets me get away with it.     I will have another hunt later and come back to you.

 

Sidecar

…………………………
3,115
1,487
Tasmania
Thanks for the info on the horizontal part of the H foil, I was really asking about the section on the horizontal part of the canard/forward rudder…..

 
Last edited by a moderator:
Since the snow has gone I pulled out my canard hull, bow rudder and stuck in a old rudder as the mainfoil just for show 

weight of that hull is 12.3 kg in tortured 3 mm ply 5 mm core cell and 200 gm carbon .so a little heavy but stiff and strong.

bow rudder is pretty crude but definitely needs a symmetric foil section for equivalent up down function . The idea with the 60126 was progressively increasing lift to balance increased drive force  which did not work.Amusing  but I do not think I will return to it . If any one wants the hull and bow rudder you are welcome to it .

FD429ED7-736C-4022-9965-0F94DEFA1F19.jpeg

00760D54-B961-456B-B0D7-5844D2046ACB.jpeg

B00E20A5-0678-4AFD-8EB9-31600718B4E0.jpeg

 

JulianB

Super Anarchist
1,161
1,549
Sydney mostly
Asymmetric, probably a 3% lower surface and a 6-7-8% upper surface, it was a H foil, the 2 lee-board 100% endplated the foil and maybe that's how we got such great CoL's.   The lee-boards extended 150-200mm down past the Lifting foil. I thick we found that running it at 2.5-3° AoA was optimum but obviously on takeoff it would have been 6-7° and at 28knts it was probably nominally negative.    Just went looking for it, but my front yard at the moment is atroucious, suprised Deidre lets me get away with it.     I will have another hunt later and come back to you.
Hi all, I did not hunt, it fell out of the roof and hit me on the head, talking about the 2008 49er lifting foil.

image.png

image.png

Fortunatley it's not that heavy, probably knocked some sense into me.

Span is 830mm, Cord varies from 240 -> 220 at the tips, and it's a 10% section (7 - 3)

at 9knts of BS it lifted 142 (complete 49er) + 20 (sundry foils and control gear) + 163 (crew)  = 325kgs pretty easily at about 3-3.5° AoA.

Max speed recorded was 28.5knts.

 
Amazing this implies a CoL of more than  1.4

we had a long weekend  4 days for me since I am only working  3.5 days a week until Xmas and then I retire properly!!! 
Had to get out on the water as well as a few hikes low altitude still snowing up top .

I assembled the modified F18ht with exploder A3 foils  quick and easy and took the wherry  for a row plus a couple of paddles in the kayaks . Back to Owl building 

I have pulled 3  half sections of the horizontal for the rudder out of the female mould . Needed a little repair prior to number 4 

presently fairing the leeboard  horizontal prior to making 2 moulds off it 

I put the horns on the leeboards but got carried away with the top radius  so may have to modify then prior to uni an biaxal wrapping . I changed my mind on actuation and think I will use a high field lever compression and tension strut rather than a linear actuator.Simplicity  was the primary driver Also made and epoxied the toe rails just need to sand a primer before fitting .

ordering paint from endura tomorrow but still a lot of sanding  and filling to do before prime let alone topcoat 

CD3AEEAF-A823-48B4-BE21-9C642793E52F.jpeg

2C65F2CC-124A-4BB2-BB68-4BAF0B618061.jpeg

E3C0F0B1-FF0C-4772-8A35-3290CB5F020A.jpeg

37283D67-A02B-4023-9FE6-EE9D746D1894.jpeg

983E29B3-34C8-46AF-990D-FB12FA90BA6E.jpeg

 

Sidecar

…………………………
3,115
1,487
Tasmania
Amazing this implies a CoL of more than  1.4
I make the Col ~ 1.55, for the aft foil only. If you add in the forward rudder horizontal foil area (say, a quarter of the area of the aft foil) you get a (combined) Col of ~ 1.04, which fits better with AoA’s of 3.0- 3.5 degrees.

Or it could be that the endplates really do effectively double the foil area.

 
Last edited by a moderator:
Amazing this implies a CoL of more than  1.4

we had a long weekend  4 days for me since I am only working  3.5 days a week until Xmas and then I retire properly!!! 
Had to get out on the water as well as a few hikes low altitude still snowing up top .

I assembled the modified F18ht with exploder A3 foils  quick and easy and took the wherry  for a row plus a couple of paddles in the kayaks . Back to Owl building 

I have pulled 3  half sections of the horizontal for the rudder out of the female mould . Needed a little repair prior to number 4 

presently fairing the leeboard  horizontal prior to making 2 moulds off it 

I put the horns on the leeboards but got carried away with the top radius  so may have to modify then prior to uni an biaxal wrapping . I changed my mind on actuation and think I will use a high field lever compression and tension strut rather than a linear actuator.Simplicity  was the primary driver Also made and epoxied the toe rails just need to sand a primer before fitting .

ordering paint from endura tomorrow but still a lot of sanding  and filling to do before prime let alone topcoat 

View attachment 511411

View attachment 511412

View attachment 511413

View attachment 511414

View attachment 511415
Cool Boat Shed. What is the wood boat hanging in the rafters?

 
That is Figjam my wife's moth "couch" a  mini cherub/ 29er skiff  built in 3 mm ply over stringers  ply foam bulkheads. weighs about 25 kg with deck frame and can fly on  my old foils  but is designed for a 50 kg pilot who prefers planing .

 

JulianB

Super Anarchist
1,161
1,549
Sydney mostly
I make the Col ~ 1.55, for the aft foil only. If you add in the forward rudder horizontal foil area (say, a quarter of the area of the aft foil) you get a (combined) Col of ~ 1.04, which fits better with AoA’s of 3.0- 3.5 degrees.

Or it could be that the endplates really do effectively double the foil area.
Dad's idea was that the front foil carry less than 10% of total lift, and we moved the main foil fwd and aft to acheive that.

He (and Bora) did put it down to the effectiveness of the endplates.

 

Latest posts




Top