UL SAILPLANE - Footlaunchable, foldable

Discussion in 'The light stuff area' started by ultralajt, Jan 14, 2012.

Help Support HomeBuiltAirplanes Forum by donating:

  1. Oct 27, 2012 #161

    ultralajt

    ultralajt

    ultralajt

    Well-Known Member

    Joined:
    May 10, 2009
    Messages:
    1,560
    Likes Received:
    747
    Location:
    Slovenia
    Thanks Oriol for your view on the matter. It has some sence at some facts even from my point of view! :emb: But I must not let to be redirected from my vision. ;)

    (Let us look at the prices again: Rigids: 16.750,00€ SWIFT: 25.500,00€ Archaeopteryx: 76.750,00€ !!...I believe they are way overrated, hence low sale and no many owners.)

    Regarding my glider design, tell me, why I am dreaming about, beeing active Hang Glider pilot since 1975 till 2007, Sailplane pilot for 4 years, Paraglider pilot some 5 years, yet still finding Ultralight Foldable glider interesting thing. Can guess why? I meet many "senior" HG pilots that told me how Rigids ate heavy and expencive, and that something cheaper, easier to transport and fly (3 axes), starting from feet or wheel, and landing on the wheel or skid would be the choice of many "sunday pilots". Two of my friends fly Aeros Phantom, so you bet, I learn their design in the last tiny detail.
    Sunday pilots dont need Swift or Archaeopteryx. They want something simplier, but with more fun and joy. If you count competition pilots and those that dont compete, number goes in favor to those that dont compete (sunday pilots). And they are my potential market.

    I think that my design fullfill my vision about affordable glider, that is one step ahead from ordinary intermediate Hang Glider.

    I dont think toom far ahead (serial production) at this point. I even doubt if prototype will be ever build, (prototype=money eater) but I like to think about it and I am working slowly on the plans and calculations.
    If ever this glider will be made and tested, we will see if it really fulfill my goals.
    If so, then a "market" will rise on its feets and start to showing interes about.

    If I am wrong, anyway, this is a nice "voyage" for me and my creativity. Brainstorming about such things is good. It costs me nothing yet, but give me joy and some goals. As you all can see, my ideas are based on my prevuious real experiences and previous designs I have done. Beside that I dont have some really crazy ideas and solutions, so all thing is doable. (could be wrong, but I cant see that :) ).

    Regards!

    Mitja
     
    oriol likes this.
  2. Oct 28, 2012 #162

    Head in the clouds

    Head in the clouds

    Head in the clouds

    Well-Known Member

    Joined:
    Mar 11, 2012
    Messages:
    1,983
    Likes Received:
    890
    Location:
    Gold Coast, East Coast of Australia
    Hi Mitja,

    Just a few words in support of what you are doing.

    It is quite true that it is very difficult to make money or develop a business in aviation, it is a desirable arena and so there are a lot of people want to be in it, and the market is small.

    Nonetheless many people have been successful and to do so have had to find their niche. If you aim for the competition area you are not likely to succeed because there are so many people in it full-time and they have been for a long time so their knowledge base is extensive.

    I agree with your thoughts absolutely, that the Sunday flyer arena has room in it for a better performance 'fun' glider and the most important feature is easy foldability. Performance is not such an important consideration, but easily folding into a small and light package will be assured of a market (that is why PPG are so popular). Price is important too but not as much as you might imagine, if you can make something very desirable then people will 'have to have it' regardless of the price. A low price is an advantage of course and if you can make it very simple then it will automatically be less expensive.

    Order of importance is -

    Easy foldability
    Compact folded size
    Light weight
    Performance
    Price

    Best of luck with it!
     
  3. Oct 28, 2012 #163

    oriol

    oriol

    oriol

    Well-Known Member

    Joined:
    Dec 31, 2009
    Messages:
    769
    Likes Received:
    136
    Location:
    Barcelona, Spain.
    Hi all!


    The idea of a footlaunchable airplane is one of my dreams too!;)
    Anything footlaunchable eases the regulations a lot, it may open the doors of aviation to many people if the price is competitive.

    The idea is a big aviation challenge and a thrilling a project for any homebuilder, I will be following this thread to take good inspiration for my projects too!



    Oriol
     
  4. Nov 8, 2012 #164

    DaveK

    DaveK

    DaveK

    Well-Known Member

    Joined:
    Apr 22, 2007
    Messages:
    336
    Likes Received:
    14
    Location:
    Northern California
    A few thoughts from a UL and PP type pilot. I've been really interested in getting into gliders especially UL gliders. But I can see that foot launching and weight shift are actually a big barrier for pilots coming from the private pilot world, especially if they are not young. Something like the Sandlin's Goats with a bit more performance really appeals to me. 3 axis, rolling launch, rolling landing seems ideal and sure looked like a bunch of fun when I watched him flying down in San Diego. It also seems that many of the spots perfect for launching a UL sailplane are hang glider spots and the clubs want you to be a hang glider pilot to launch. Now that might not be an absolute, but that is the impression I've gotten. Seems silly to me to go through learning to hang glide, if I intend to go straight to something that rolls and uses a stick. I think there really would be a market for a UL glider that rolls to launch, if there could be easy transition from bigger sailplanes or ULs.
     
    Topaz likes this.
  5. Nov 8, 2012 #165

    Detego

    Detego

    Detego

    Well-Known Member

    Joined:
    May 29, 2012
    Messages:
    470
    Likes Received:
    105
    Location:
    North America


    I stopped driving to mountains for foot-launching hang gliders back in the late 80's; Towing, Winch and Power is the way to go; saves much time in traveling and waiting on the weather.
     
  6. Nov 9, 2012 #166

    ultralajt

    ultralajt

    ultralajt

    Well-Known Member

    Joined:
    May 10, 2009
    Messages:
    1,560
    Likes Received:
    747
    Location:
    Slovenia
    I wrote on the first page of this thread, explaining the glider, also about rolling launch, and also about version with completely closed botttom side of the cockpit, which convert this footlaunchable to "ordinary" glider.

    Maybe this part of the text was hidden inside a huge ammount of writing, but somethimes it is worth to read all to catch what I am thinking of, in order not to be missunderstod.

    Mitja
     
    Last edited: Nov 9, 2012
  7. Nov 23, 2012 #167
    Any Progress????
     
  8. Nov 23, 2012 #168

    ultralajt

    ultralajt

    ultralajt

    Well-Known Member

    Joined:
    May 10, 2009
    Messages:
    1,560
    Likes Received:
    747
    Location:
    Slovenia
    This project is not my primary, but it going forward from time to time, when I cam up with some solutions of details and parts and I put them on the paper imidiately.

    Project is "on hold" at this moment as I was working on the completition of electric RC model 2,6m wingspan, workshop plans, and I am also working on the desig of new RC Vintage glider. There is also a new, larher than previous CNC router machine in designing stage.. It is always workoholic atmosphere at my place :)

    [​IMG]

    [​IMG]

    As you can see, I like to draw plans for my designs. It is kind of my obsession, and plans for my Ultralight Sailplane will be also of the same quality.

    Regards!

    Mitja
     
  9. Nov 24, 2012 #169

    Head in the clouds

    Head in the clouds

    Head in the clouds

    Well-Known Member

    Joined:
    Mar 11, 2012
    Messages:
    1,983
    Likes Received:
    890
    Location:
    Gold Coast, East Coast of Australia
    Excellent drafting Mitja!
     
  10. Nov 26, 2012 #170
    Lucky you ... I dream to have a complete and to live in my own workshop .. it is something related to my childhood dreams ... my room was my Lab and Mom used to give me so much headache for that :)

    Nice drafting .. and nice projects you are working on .. wish you all best ... my interest of your fordable project is based on a new interest I have in foot launched sailplanes ... but a bit different ...

    It goes about the same needs and approche .. yet it would be a Canard ... I have a vision yet it has to wait till my situation get sorted out .. :-(

    Best of luck man .. and happy flying ..
     
  11. Dec 11, 2012 #171

    ultralajt

    ultralajt

    ultralajt

    Well-Known Member

    Joined:
    May 10, 2009
    Messages:
    1,560
    Likes Received:
    747
    Location:
    Slovenia
    Thanks! :emb:


    I have mixed feelings about Canard type of sailplane. I am convinced that traditioanal layout (tailed planform) is more controlable and fast respond than canard. One need crisp, fast and safe respond of controls when thermaling or flying on the ridge lift.
     
    Last edited: Dec 11, 2012
  12. Dec 11, 2012 #172

    ultralajt

    ultralajt

    ultralajt

    Well-Known Member

    Joined:
    May 10, 2009
    Messages:
    1,560
    Likes Received:
    747
    Location:
    Slovenia
    Hi!

    Couple of days ago I installed X-Plane program on my computer.
    I know about this program many years already and even installed it back then, but I find hard to make my own plane for thr simulator.

    But lately I find some very informative video tutorials on youtube, so a decision to install program, "build" my plane and try to fly it in the X-Plane simulator was final.

    A demo version of program allow all features, except joystick flight control is disabled after 15 min of flight (each time), so that is more than fair for me.

    I am looking forward to build 3D model of my sailplane in X-Plane, Plane Maked. [​IMG]

    I will make some reports of my progress here.

    I am aware that our Orion wrote about this software (click) and was not enthusiastic about, as an aeroplane design and testing tool, but that is not my intention. I just want to see my Sailplane flying in graphically nice simulation. [​IMG] to keep me busy and to get some more elan...

    On the other hands, Synergy wrote some another view on that software.

    I dont want to induce here an arguing about X-plane "Pro et Contra" please. I just want to make nice visualization of my project.

    I found many pretty visualizations, made by X-plane that are asthonishing.

    Mitja
     
    Last edited: Dec 11, 2012
  13. Dec 11, 2012 #173

    PTAirco

    PTAirco

    PTAirco

    Well-Known Member

    Joined:
    Sep 21, 2003
    Messages:
    3,476
    Likes Received:
    996
    Location:
    Corona CA
    I have read somewhere that an accurately modeled aircraft in X-plane can come within a few % of the full size version, consistently. "Within few %" seems like a very useful tool to me. I doubt any amount of paper and pencil calculations will get you much closer.

    I have X-plane, but really accurate modeling and design requires quite a bit of time and effort and there is a lot to be learned to use it efficiently. If I had the time, I would not hesitate to learn this for a new design.
     
  14. Dec 13, 2012 #174



    Well it is true ... yet without taking a chance ... and not forgetting the lessons learned .. well keep building the same aircraft with minor modifications ..
    All those great names in our history are none because they solved the problem others didn't even consider ... am not a great name am just a man with a dream :)

    Yet .. a person like you .. I fined very sad-full to be conservative ... I see your achievements and think what you might be capable of .... I think you could solve a conquer couple of dilemmas just like the Horten brothers and provoke some new design philosophy in our community ... maybe an airplane or two flying too ...
     
  15. Dec 13, 2012 #175

    bmcj

    bmcj

    bmcj

    Well-Known Member HBA Supporter

    Joined:
    Apr 10, 2007
    Messages:
    12,837
    Likes Received:
    4,799
    Location:
    Fresno, California
    I think the canard can respond as quick and crisp as a conventional. Where it might fall short is the inability to achieve max L/D of the main wing due to the AOA restriction relative to the canard (a big detriment to soaring capabilities). It also eliminates (or at least complicates) the ability to add flaps or spoilers.
     
  16. Dec 13, 2012 #176

    Topaz

    Topaz

    Topaz

    Super Moderator

    Joined:
    Jul 30, 2005
    Messages:
    13,628
    Likes Received:
    5,279
    Location:
    Orange County, California
    It also runs afoul of some other basic aerodynamics. Aspect ratio is span^2/lifting area. A canard is counted as part of the lifting area, since it not only trims the aircraft but shares a substantial (often 20% or so) amount of the lifting load with the wing. Sailplanes are critical on aspect ratio and span. You don't see them with long skinny wings just because we think it looks good. That extra area (in the canard) is more profitably put out on the main wing, adding to the total span.

    Even more importantly, the canard downwash field (and upwash field outboard of its tips) is going to highly influence the lift distribution on the main wing. It's possible (but very difficult) to tailor the twist distribution of the main wing to counter this effect, but that will only be effective at a single lift coefficient (airspeed), and the lift distribution will be highly non-optimal at every other lift coefficient (airspeed). The farther from optimal the lift distribution, the more induced drag is produced. You could easily see a 20-40% penalty in induced drag in some conditions. With a sailplane, you simply cannot afford that kind of penalty.

    A low- or medium-performance glider might "get away with it", if you have some critical reason to use a canard, but the soaring performance will always be somewhat inferior to that of an equivalent "conventional" glider. For a high-performance glider/sailplane, the performance penalties for a canard configuration will be big enough to render the aircraft completely noncompetitive.
     
    ultralajt likes this.
  17. Dec 13, 2012 #177
    OK guyz ... I didn't wanna make this post drift away from it's original subject ... but the discussion started .. (Who let the evil out?!!) ... :)

    OK ... all have valid and correct point view ... it all depends on the "Problem" - "Need" - "Quest" .. call it what ever you like ...

    In my case ... later on when I get in a more stabilized situation I'll start this project ... and the "Problem" - "Need" - "Quest" .. is: "A fold-able .. easy transported/stored sailplane .. to teach on and allow for ... a fun .. low speed .. aircraft for my beginner friends" ...

    A Canard would be the logical path to think about ... yet .. this does not judge if it is the best or not ... this thing would be accomplished in the "Conceptual Design Phase" ...

    So .. both of the opinions are valid and have merit .. it just depends on the parameters of the "Problem" ...
     
    Last edited by a moderator: Dec 13, 2012
  18. Dec 14, 2012 #178

    autoreply

    autoreply

    autoreply

    Moderator

    Joined:
    Jul 8, 2009
    Messages:
    10,732
    Likes Received:
    2,540
    Location:
    Rotterdam, Netherlands
    Canards ruin any chance of laminar flow over the fuselage. Drag just went up by 50%...
     
    Topaz likes this.
  19. Dec 29, 2012 #179

    ultralajt

    ultralajt

    ultralajt

    Well-Known Member

    Joined:
    May 10, 2009
    Messages:
    1,560
    Likes Received:
    747
    Location:
    Slovenia
    Darn.... I am distracted again from my original wing design...
    While browsing trough my collection of some rigid wings, a Impact rigid wing (again) take my attention to one detail!
    My design of the wing is made from a D tube spar on the nose and rear spar, that are spread appart by four compression struts.
    As I would like to make my wing as light as possible, this rear spar that is loaded in bending by tension load in wingsail, must be pretty bulky and of course heavy.
    If I go back to the Impact wing design, I get rid of that spar, and only aileron and flaps spar would be necessarry. Probably this will resulted in a lighter awerall construction.
    Let me shown some photos, that attracts me (to show what I am talking about, and for the future reference):

    flugel_von_innen.jpg 07querruder.jpg 1081071175390.jpg 1081069724343.jpg

    Impact wing structure looks very "clean" and it is totaly colapsible. I like the flap and aileron detail.
     
  20. Dec 31, 2012 #180

    ultralajt

    ultralajt

    ultralajt

    Well-Known Member

    Joined:
    May 10, 2009
    Messages:
    1,560
    Likes Received:
    747
    Location:
    Slovenia
    Regardles the Impact wing awesome detail at control surfaces joint is attempting, I will not do such drastic change in my basic layout for now.
    I think that I should ask the Impact glider designer for permission to use some of his design details. Not as pure copy, but just as a principe of some among them. Maybe I will write an email to Mr. Olaf...
    I will look again at that design only if my wing weight will be higher than desired target weight. Then the rear spar is the first thing to get rid off.

    Mitja
     
    Last edited: Dec 31, 2012

Share This Page

arrow_white