Richard Harris Posted October 17, 2011 Share Posted October 17, 2011 Always fancied having ago at one of these and after an impulse buy from our Chinese friends received a kite in the post Saturday morning! well, a para foil as they are called for less than a round at the local. I know absolutely diddley squat about these things and have had to search hard for any kind of information on the theory. This coming weeks forecast is pretty grim and no good for flying so I thought I would make a start yesterday on my OD paramotor. The fuselage as we know it (gondala to the purists) is constructed from 3mm lite ply and balsa. I have swiped the UC off one of my autogyros for quickness (ok I'm lazy). Two servos are mounted in the base of the fuselage and will have long Fibre Glass attached so as to get the stroke needed to turn it. These cords are attached to each arm and will run up through a supporting arm to each side of the rear of the foil. Pull the left rear side down and I read it should turn to the left and vice versa! Pull them down together to control the height/speed. Through the top of the fuselage is a carbon rod which the main foil straps will be fastened to. These straps/strings are connected to the front and middle of the foil and have to be adjusted to get the Angle of Attack correct. Getting the AoA seems to be what everyone raves about so that will be done at the field. Here are a few pictures of what I have done so far. Rich Quote Link to comment Share on other sites More sharing options...
Chris Bott - Moderator Posted October 17, 2011 Share Posted October 17, 2011 Looking good Richard, I had a good look at these myself but now you have started I may wait until you've worked out how to do it. How about a "ParaWebbit"? (only joking of course). Quote Link to comment Share on other sites More sharing options...
Tom Wright 2 Posted October 18, 2011 Share Posted October 18, 2011 Hi Rich . You do like a challenge ! . Stuart Eggerton has one and setting up the lines can be tricky, he will be glued to you thread to see the outcome . The pod design looks to have borrowed a bit from the autogyro exploits,Stu bought the aluminium pod which I have just married up to a 450 W motor ,we will be watching progress with great interest. Tom.Edited By Tim Mackey on 18/10/2011 08:51:59 Quote Link to comment Share on other sites More sharing options...
Biggles' Elder Brother - Moderator Posted October 18, 2011 Share Posted October 18, 2011 Interesting project Rich. Any ideas yet on how you're going to launch it? BEB Quote Link to comment Share on other sites More sharing options...
kc Posted October 18, 2011 Share Posted October 18, 2011 What is the wing span and area? And the weight of the fuselage & gear? My worry would be that the lifting power will be so great it might be difficult to control it and a fly away could result. Having seen the power of a kite dragging a man across the grass when the wind was only a stiff breeze ( we were flying Wot4 's and things at the time ) this gives more respect for the wind! I would say compare the area to that of a windsurfers kite and the weight of a man to the weight of the fuselage.to see if it would be blown away. Quote Link to comment Share on other sites More sharing options...
Richard Harris Posted October 18, 2011 Author Share Posted October 18, 2011 Chris, LOL!, I'm all done with Webbit's thank you Tom, If you have Stuarts to hand I woudn't mind a few dimensions if you get chance? What is the distance between the mounts for the main line straps? When hung from that position with everything on board what is the attitude of the fuselage? Do you think this matters or is it the total mass underneath the foil that is important? Like a pendulum effect? BEB, Not thought that far in advance! but I am sure it will be interesting to say the least! KC, The wing span is 2.1m and as for the Gondalo's weight I am not that far into the build as I type. But off the top of my solar panel I reckon roughly about 1.5kg. I can understand your thoughts of the lifting power of these kites and would guess that it may not be appropriate for windy conditions. But the AoA will be controlled to a certain degree and I'm hoping that I will have enough weight to penetrate. The rest will be in the hands of the para foil gods! My one concern is the prop torque, I will be using a 12 " prop and was thinking of offsetting the thrust line to compensate this. This I have done on my pusher type autogyros to good effect. But I experimented once doing this and when the fin was removed thrust alignment become almost impossible to gauge. So maybe it will be worth while adding some kind of vertical stabilizer somewhere in the prop wash? Every one that I have seen doesn't, so maybe I am thinking too much about a this nd shouldn't try to re invent the wheel! Rich Quote Link to comment Share on other sites More sharing options...
kc Posted October 18, 2011 Share Posted October 18, 2011 Well I may be talking about something I know little of, but that seems a massive wing for the weight. I thought the man carrying ones were only twice that size ( I may be wrong! ) So perhaps yours is a quarter the area of one that carries a 50 kilo or more man. Maybe yours could weigh 10 kilos or more and fly.Put another way if I built a vintage fixed wing model of 2.1 metre span which weighed 1.5 kilos would I stand a chance of keeping it in sight & on the site in anything more than a slight breeze? I hope I am wrong............ Quote Link to comment Share on other sites More sharing options...
Biggles' Elder Brother - Moderator Posted October 18, 2011 Share Posted October 18, 2011 Hi Richard, the reason I was asking is that - unless I've misunderstood - you dont have any framework on the "kite" itself. Are you considering some sort of "spreader" on the wing to keep it open at launch time? BEB Quote Link to comment Share on other sites More sharing options...
Biggles' Elder Brother - Moderator Posted October 18, 2011 Share Posted October 18, 2011 On the directional issue. Yes it is confusing isn't it. Without a fin surely it would just weathercock into wind? This is fine for kite but a little less than satisfactory for an aeroplane! But of course you are right - the full size ones don't have this so how do they mamage? I do sometimes watch the para-karts on the beach near where I live. They use this type of "wing" - but whatever direction they are travelling in the kite is always deployed in a downwind direction - ie headed straight into wind. But of course they have the friction of big chunky tyres to keep them going in the right direction! BEB Quote Link to comment Share on other sites More sharing options...
Ben B Posted October 18, 2011 Share Posted October 18, 2011 Very nice! always suspected they'd make stable FPV video platforms so watching with interest Quote Link to comment Share on other sites More sharing options...
kevin wild Posted October 18, 2011 Share Posted October 18, 2011 great idea. if the servos are mixed with the elevator would you get climb/descent or is it throttle control for height ? kev Quote Link to comment Share on other sites More sharing options...
Seamus O'Leprosy Posted October 18, 2011 Share Posted October 18, 2011 For anyone who has £30 to spend and wants to give it a goMay I suggest Paraglider Parafoil 2.15m and BelaTrike 2.15m Alloy Gondola Kit Some detail Photos Quote Link to comment Share on other sites More sharing options...
kc Posted October 18, 2011 Share Posted October 18, 2011 Having looked at the commercial version that is about the same weight & size I reckon I must withdraw my comments! There must be more control of the lift than I expected.Good luck with the project. Quote Link to comment Share on other sites More sharing options...
Craig Spence Posted October 18, 2011 Share Posted October 18, 2011 This looks very interesting and should it work well I may give it a go. I fly traction kites a little and a few things I have picked up on may help you.The cord arrangement on these kits leads off to four control lines. The top two control lines are exactly that "control lines", these move the kite left, right and that's it. You control your height by steering into wind and holding it there, the wind blowing through the foil raises it like a wing would, to loose height you steer out of wind. Or use the brakes.The second set of lines "lower ones" are the brakes, if you pull these it collapses the back of the foil, breaking the lift and the foil/ kite simply drops from the sky until you release the brakes at which point the foil re-inflates.A few points to note, one of the guys quoted seeing a guy being pulled around by the foil. This is true, they are very powerful but only when at a certain angle of attack.If you fly the kite as high as you can it levels off and you bately get any pull at all. At this point I would say the foil could fly itself.So I would suggest your angle of attack be the same as most planes, your CofG will be automatically set by the cords, you would just have to get the weight right.I would very carefully consider your steering methods, although they seem fine at the moment if your over bake your control movements it will colapse and fall.If it's steering via the brake lines I would make the movements minimul to begin with, or it may fall like a stone, which would be recoverable if your quick enough.You may have already known this so appologies in advance, look forward to seeing this go up.Nice to see people giving themselves a challenge. Quote Link to comment Share on other sites More sharing options...
Stuart Eggerton Posted October 18, 2011 Share Posted October 18, 2011 Hi Richard, I also have the Hobbyking para foil and in addition the Bela trike designed by Beladog as Tom says, see here The distance between the attachment straps (centre to centre) is about 104 mm on the bela trike. I would recommend going to the hobbyking forum and searching paragliders and paramotors. There is a thread called AOA adjustment by Beladog, (he seems to be the authority on these kind of machines and did design the bela trike for Hobbyking) and you must follow this information if your foil is to have any chance of flying. My trike is almost at the point of ready to test, but just need so reasonable weather!. Edited By Biggles' Elder Brother - Moderator on 18/10/2011 19:31:52 Quote Link to comment Share on other sites More sharing options...
Stuart Eggerton Posted October 18, 2011 Share Posted October 18, 2011 A video of when the set up has been done well, these things do fly! Quote Link to comment Share on other sites More sharing options...
Biggles' Elder Brother - Moderator Posted October 18, 2011 Share Posted October 18, 2011 Stuart - please read this Thanks BEBEdited By Biggles' Elder Brother - Moderator on 18/10/2011 19:34:13 Quote Link to comment Share on other sites More sharing options...
Richard Harris Posted October 18, 2011 Author Share Posted October 18, 2011 Thanks for all the info gents I have to say I am still trying to get my head around how they work, especially the pitch control I have made up the 'anchor' points for the main foil, these are from duraluminium tube and will be glued over a carbon rod that runs through the top of the mast/gondala/ top of the fuselage or what ever it is called! 2 pneumatic pipe 'P' clips will be used to hold the removable 'Jesus rods'. At the edges are guide holes for the 2 control strings to run through to attach to the servo arms. On all of these things that I have seen there is some kind of shroud around the prop, all I can think of is that is protection for the foil/kite strings? I will make a couple of hoops out of 8mm dia pneumatic air pipe tomorrow along some brackets. Rich Quote Link to comment Share on other sites More sharing options...
Vecchio Austriaco Posted October 18, 2011 Share Posted October 18, 2011 Hi Richard, I can see you like extraordinary flying machines. I am looking forward to your flight experience with that one! I am sure you master it after all your autogyro experience including Webbit conversion! Cheers VA Quote Link to comment Share on other sites More sharing options...
Richard Harris Posted October 20, 2011 Author Share Posted October 20, 2011 VA...cheers Instead of using the standard cross motor mount I decided to make one out of GF sheet to incorporate the mounts for the horizontal stays to which the ply duct is mounted. I did try the air pipe for this but I just think the ply duct looks better. Also added is a rudder which I am hoping will eliminate prop torque, this will have to be set with left trim and will be tested by hanging the fuselage up and applying power until it stops rotating. Well that is the plan! Extended servo arms have been fabricated from duraluminium and bolted onto the standard arms. I don't like this as I think the plastic female splines will be a weak point, but I will try it out for testing purposes. I can always get alloy arms after if it does fly. A few pictures of what we have so far, its all just loosely put together so that is the reason for the 'not square duct'. The AUW as you see it is 800 grammes or there a bouts with the motor and a 3 cell Lipo on board. If it ends up a little light I have room for a 4 cell pack, the 4 max is good for 5 cells, prop fitted is a 12 x 8 APC jobbie. Rich Quote Link to comment Share on other sites More sharing options...
David Gilder Posted October 20, 2011 Share Posted October 20, 2011 Rich. Just noticed that you have a rudder on the trike!! Are you planning to steer using this? As I understand (and have seen on other manufactured products) they dont have ground steering and in the air the steering is controlled by the trailing edges of one side of the foil bing pulled downwards...(left trailing edge down = left turn) Sorry if thats confusing... Just curious!!! Dave Edited By David Gilder on 20/10/2011 12:44:44 Quote Link to comment Share on other sites More sharing options...
Richard Harris Posted October 20, 2011 Author Share Posted October 20, 2011 Dave, The rudder will be fixed, it is there purely as a stabiliser. I was going to trim it to the left but thinking about it this may not be wise due to varying speed of the prop. The motor will be offset from the vertical centre line about 6mm to the right (kind of like right thrust but a purer way of achieving it) looking from behind. When hung from a string in theory if the motor is mounted on the centre line the fuselage will rotate anti clockwise with power applied. As the motor is moved to the right of the centre line it should neutralise this effect, but only when a vertical stabiliser is in the prop wash. Without one it will just spin which ever way it wants. If set up right when power is applied the fuselage should just sit there under power. It is the way I set up my pusher autogyros and is nothing new. Is it needed? probably not. I just like to play Rich Quote Link to comment Share on other sites More sharing options...
David Gilder Posted October 20, 2011 Share Posted October 20, 2011 That sounds fine Rich. I was just curious as in the pic it appeared to be cantered to the left like a rudder.. You have explaied that very clearly.. thanks Look forward to seeing it in the air!! Dave Quote Link to comment Share on other sites More sharing options...
FunnyFlyer Posted October 20, 2011 Share Posted October 20, 2011 Fascinating! I built one of these Windbags in the mid 80s. It cheated by having a canard elevator, but used weight shift for directional control, via a winch servo. This is not me in the pic - just some random dude from an internet search. Quote Link to comment Share on other sites More sharing options...
David Gilder Posted October 20, 2011 Share Posted October 20, 2011 This is what I have!! Dave Quote Link to comment Share on other sites More sharing options...
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