Presentation

   This is the project page of my F3i sailplane, which is curently in worshop at Supaero school. I am working on it with the help of a friend.
   F3i is a FAI rule for sailplanes with span larger than 3500mm, that uses aerotowing to start. It is a "speed - duration" event.

   The wing of this sailplane is being built after a theorical study.
   We can describe this project into 4 parts :

• A precise reading of FAI rules, in order to find precise requirement.
• A study of flight mechanic for the F3i events, in order to define main parameters (AR, wing loading, etc )
• A study of wing aerodynamics, for precise geometry and airfoils.
• Building (full composite carbon and glass fiber) of the wing.

More precisely for the wing :

Calculation.

   For the design of my f3i sailplane, I needed some ways to evaluate performance. I made those excel sheet.

• Calculation of glider's polar.
     I is quite simple to calculate lift, but drag is much moire difficult. Here is displayed some evalutation of Cd for sailplane, giving an idea of glider's polar.
  
• Simulation of speed task.
     This sheet allows you to catch the best run your glider is able to do. Don't forget to estimate Cd for your glider (see the former item).
     You can adjust :
• Sailplane : weight, Cd, Cl max, area.
• The flight path, to be set by user.
• Some external parameter : temperature, pressure, lift (thermal or hang) (in project : parallelism problem according to ideal flight path, air moisture, wind).

Airfoils

   Marcel Guwang has empiriqualy created airfoils that works so well(MG-06 and now MG-08), I tried to understand why. I applied designs ideas to a modified HQ2/09.

The HQ2/09is really well known in F3i world. But he lacks low reynolds and flaps hability.

   

The MG-08 was modified from MH-32, for Cd and Cm reduction : it is almost a reflexed airfoil. He behaves really well with flaps. But He lacks Clmax.

Leading edges of MG-08 and HQ2/09 are quite similar, whereas the trailing edges are really different. I tried to adapt almost reflexed TE on HQ2/09, and that works quite well !

Main airfoil : MS 1,9/8,7.
   According to Xfoil, results are quite good. Flaps hability is nice, and Cd is much lower than HQ2/09 for low reynolds.

Root airfoil : MS 2/9,5
The main airfoil was adapted to another root airfoil for different reasons :

• Re number is higher at root, so that the drag of HQ2/09 is quite similar to MS 1,9/8,7, while HQ2/09 has a better Clmax.
• We should not forget root strenght (5kg at 12G acceleration...).

So, MS 1,9/8,7 was slightly thickened and cambered, and we keep better flap hability than HQ.

Data on those airfoils :
Coordinates :	MS 1,9/8,7	MS 2/9,5
polars Re constant, Resqrt(Cz)constant, effect of flaps

My other airfoils.

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Project state at 08/11/2002 :

Building is going on. The flaps and ailerons were cut, and the hinges are being made.

On the left, Compared to Scoop wing. Jade has more AR, and a more complex planform.                On the right you can see the ailerons and flaps.

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... at 14/01/2002 :

Here are images of the right wing.

There is still quite much work left on those wing before we can see them fly !

Still in the vacuum bag
Just out of the mould...

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... at 23/11/2001 :

I found time to carry on with the vaccum bag.

here is the left wing, th first to have been moulded.

The wing just out of the mould, awaiting sanding the LA and TE...

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... 14/10/2001 :

Building is going on !
    Spars were integrated to foam core.
   Intrados composite were made. The wing is awaiting the extrados skin and the rest of the wing into a single operation.

	Intrados skins
		Foam core with spar, and extrados in preparation.

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... 29/06/2001 :

   The project is now stalled, for hollyday reason... I will resume the building of the wing after those summer holidays.
   Some news about the project:

• The project got a name : Jade
• The main spar, including central wing joining, was made mainly from carbon. It is ready to be fitted into the foam.
• The skins are still to be made intao the molds.

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... 20/06/2001 :

	Nice, isn't it !!
		With foam.

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... 07/06/2001 :

• Mould are finished, after many step of sanding, painting and so on.
• Main spar is being computed.
• Foam is about to be cut again.

... 22/05/2001 :

	Tip detail
	The sanded moulds

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... 10/05/2001 :

The airfoils...
	Moulds are made from foam, covered with GF.

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