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D.Bernardin
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Posted: Fri Jun 5th, 2009 11:57 am |
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As I dont want to infest more Patricia's openning warnings, I try to open this new topic .
Then I resume : this plane has a center biplane part ; the wings are close together and leading edge of rear wing follows immediatly (or not?) trailing edge of front one . As the airfoils are of high-lift kind and set with an angle of 4º to 8º a tail is necessary . Panels close this part and a pair of winggrids complete the whole (forget it! it was a mistake) . That is the glider !
To row in air the pilot moves a part of the windgrid . Proofs are necessary to select the best arrangement , but as an exemple nº 1 could be fixed nº2 and 3 flapping and 4th blade fixed . Since winglet's movement is up and down and also back and forward , the first blade must be swept forward and with dihedral . The rear one "more or less" ... all the contrary ! (EDIT: perhaps I'll try to make it simpler).
I dont trust in a full aeroelastic control of incidence ! Thus my moving winglets are very flexible and an internal dispositive limit the natural twist . I will put drawings to explain it ; at less this arrangement has two positions : gliding and rowing or better 3 to allow good efficiency in both research of best vertical speed and at transition speed . In a few words this mechanism consist in a fork slipping on the spar, limiting the vertical movement of a tip-stick similar to the delta wings one . The skin is stretched on a delta-type structure. Battens stop in the LE gutter, stronger than a delta LE, linked with both the tip's ribs and with the spar. Nevertheless it can twist around the spar.
Lower part and upper part of the covering cloth are separated and the openning of the trailing edge could be lightly blown by air taken at the leading edge , as well to control flow in this badly closed TE and inflate the skin .
Edit: the fork would had been too fragile. Nevertheless, take the idea, with any treatment it could be usefull. I prefer now other control of flexibility, that I put lower.
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 Last edited on Sat Dec 19th, 2009 05:49 am by D.Bernardin
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D.Bernardin
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Posted: Fri Jun 5th, 2009 01:08 pm |
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A full rowing disposition looks me unproductive , perhaps necessary to take off , but since we can start from a hill ... I suppose that human power is nearly the same cycling or push-pulling with both legs , but only legs . Forgive me , the extra power that can give rowing during a very short time looks of a few interest when it means less power in a continuous effort . To avoid (or control) the CG displacement, a proportional movement of the seat must be obtained of the strings and pulley system .
Arms are moving the winglets back and forward independently , that allows to control pitch and bank . The pilot will have to learn a movement associating research of stability and efficiency of flapping , but will have only to win the drag of the winglets while he will be looking for control . The experience of propeller's HPA seems to indicate that control and high power production are difficult to join . An aerobic effort of 200-300W that is all that produce human being !!! At the cost of concentration !!!
So we must choose :
-or a glider that can fly in many weather conditions , nearly small ;
-or a big one , only able to fly with few wind and turbulence . The first one does not take off nor climb . Flapping gives it a high L/D ratio . For exemple a 20 L/D glider could have 40 when flapping . 40 allows long flights !
"Grosso modo" the first one is 12 meters span ... or less , the other 15 meters and more .
Last edited on Sat Dec 19th, 2009 05:50 am by D.Bernardin
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D.Bernardin
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Posted: Sat Jun 6th, 2009 02:38 pm |
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First I want to beg your perdon for my bad English and the mistakes I let . Indeed the funny one is (was) to raw in place of to row . I will try to take care and make easier the task of people who read me . Perhaps there is a way to modify my letter ? (I found !)
Just a detail : in the flexible winglet , a light spar would lead the battens to follow step by step the twisting effect of the negative cm 0,25 airfoil associated with front situated spar . Would it give a correct AOA or may I have to tune this part ? I dont know if propeller theory can be applied . At least I have to learn about it and practice . I hope that my choice of a quick flapping wing helps me a few by a later stall with consecutive tolerance at wrong AOA .
Then I follow the description .
Most of the control of attitude is obtained by the symmetric or asymmetric displacement of the winglets . A trim could modify AOA of the stabilizer, and it could be necessary to add a real yaw control : a vertical tail-plane , nothing else . Brakes add drag , even when not in use . Ailerons too and I would like to have "pure" center wings
Pilot have to enter in a fairing . It has to be open at the bottom for take-off and landing, but I hope that the doors join well to eliminate a silly source of parasitic drag .
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 Last edited on Fri Dec 18th, 2009 10:42 pm by D.Bernardin
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D.Bernardin
Member
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Posted: Sat Jun 6th, 2009 07:05 pm |
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Then , I resume my conception :
-a near-wing-biplane-box-wing : (EDIT : box-wing did not worked well with a kind of moving winggrids at the tips, so there is now a strut articulated on one of the wings)
to have a good structural disposition , to benefit of " Nenadowitch effect " if exists (or call it the manner you want) , to have more span efficiency with a quite small airplane "et toute cette sorte de choses" !
-an hybrid ! I would prefer to call it semi-ornithopter but it is the law :
to flap rather quickly , having a little unsteady effects remaining , to avoid a demultiplication , to feel what is flapping in legs and arms .
-not a flying-bicycle nor a rowing-air-vessel ( we could call it semi-rowing perhaps ?) :
to be able to change amplitude , to feel the wings and to be sufficiently conscious to keep the flight line more or less horizontal 
If you want , if you can , put some more watts when you are angry !
I will put ideas about flex-controlled wings and airfoil choice in the threads corresponding .
Here is the strut : it is hardly fixed in the rear wing just in front of the spar and articulated on a tube fixed in the front-wing spar
Rear view of the "glider" part :
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 Last edited on Sat Dec 19th, 2009 05:55 am by D.Bernardin
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D.Bernardin
Member
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Posted: Fri Dec 18th, 2009 06:02 pm |
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To have anything working securely, the control of flexibility has been changed. A bow
blade is driven forward and backward by a cable and a sandow, so the movements of the tip-rib are under control. The gotter has been moved forward for clarity.
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D.Bernardin
Member
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Posted: Fri Dec 18th, 2009 06:30 pm |
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To follow a conic path controlled by pilots arms, the wing must be articulated. Jon Howes solution, using a skew-hinge would be nice. I prefer to give at the pilot the complete control of the path of the tips, so he could accelerate his movement in the bottom part of the run and force backward. All that before the necessary slowing down, then up, of the up-phase. My drawing shows two articulations, first is close to the fixed-center-wing and is hand's driven, second one is fully automatic, driven by elastic strings. Flexibility control is repeated at central articulation. The very light rear spar (carbon fiber?) must be cut, the bow-blade ensure the link.
A simpler way is to report the controlled articulation at the first third part, more like in Jon Howes project . A bow blade linking the first third part and the remaining one can be let uncontrolled, twisting a little when flapping and not too much when gliding.
Pink is for the bow-blades, blue for the strings, black for the rubber's parts, i.e. sandow and silent-bloc :
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 Last edited on Sat Dec 19th, 2009 05:57 am by D.Bernardin
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D.Bernardin
Member
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Posted: Fri Dec 18th, 2009 06:56 pm |
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Here is the tip of right wings. The feathers are on the front wing, whose lift is currently higher than rear one. Skew-hinges are used on the feathers, first to avoid overload, in second place to lose AOA when the influence of the flapping wing give them a lift increase. So lift turns in thrust. Remains a little problem to turn and bank, also to pull-out. Any control is needeed.
Note : in this view, the strut is fixed in front wing (in a chest between two strong ribs) and articulated in rear wing. In the contrary disposition described above, the chest is shorter, then lighter. Anything is changed too in the inter-action between strut and wings.
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 Last edited on Fri Dec 18th, 2009 07:10 pm by D.Bernardin
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D.Bernardin
Member
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Posted: Fri Dec 18th, 2009 07:20 pm |
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The same wing tip. You can see I am in debt with Jon Howes . Some differences indeed : the feathers remain nearly parallels and their roots evolve quickly to a thin airfoil.
Foam-ribs fill the articulations. Indeed we must find a light one !
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 Last edited on Fri Dec 18th, 2009 10:22 pm by D.Bernardin
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D.Bernardin
Member
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Posted: Fri Dec 18th, 2009 08:04 pm |
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A long time ago, six month (!), the orni had panels linking front to rear wing. Although the wings need to be linked, spanwise circulation has to be respected. The flapping part though little, influence on fixed part stream. Also: the tips are necessarily free, then we cannot accept one vortex at the end plate of the fixed part and another at the tips.
You can look at the attachment I had edited before in the thread "spanwise circulation of a biplane wing". There you can see the little ghost produced by Colab wings, it is particular, probably contains few energy, but remains a vortex. Can a Colab wing be enlarged by a flapping winglet ? Does it improve the wing circulation ? Many questions. I prefer my solution... at the moment I write ...
COLAB PROJECT : http:http://www.colabsystems.com
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 Last edited on Sun Dec 27th, 2009 06:40 pm by D.Bernardin
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D.Bernardin
Member
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Posted: Fri Dec 18th, 2009 09:13 pm |
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Another thing : we have to avoid panels because of their drag, not only their own drag and the inter-action one, but the drag they have at the minimum oblique attack due to the particulars turns of our slow machines. Struts shall have a thick section for that reason, also to minimize circulation between top wing and lower one.
If you can read French or Spanish, enter in my blog
http://lornito.blogspot.com
http://elornitoptero.blogspot.com
I tell the same, and a little more.
An old model of mine (very bad at turn and bank!):
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 Last edited on Fri Dec 18th, 2009 11:13 pm by D.Bernardin
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D.Bernardin
Member
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Posted: Sat Dec 19th, 2009 11:17 pm |
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To reduce the charge on the spars, Colab project and mine use the same way : articulation. In the case of a semi-ornithopter the articulated part cannot be fully developped.
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