Wednesday, February 15, 2012

Willow F3F, a budget friendly F3F sailplane


Designed by Ian Mason, manufactured in China, and distributed by G-Fly for France, Germany, and Italy, the Willow intends to be a budget friendly sailplane for F3F and sport flying (from 670 €).

http://www.g-fly.it/alianti/willow-f3f.html
Before to have a look at the kit, let's say few words about the genesis and design: Ian Mason started the development 2 years ago but the plane really exist for a year. The objective of the Willow was to release an affordable F3F plane, providing lot's of fun with sport flying, but still very capable in F3F, allowing newcomers to this category to give a try.

There is no secret to keep the cost down. It starts during design phase by doing some trades off. Therefore there is nothing revolutionnary, only proven solutions. The section is derived from the RG15, the planform is inspired by the Race M, which was and still is a competitive plane. The Willow is rather compact with its 2.75m wingspan. The fuselage is large enough to host standard servos. The V-tail is in one piece, which simplify the manufacturing ( no joiner, no tube needed).

On the manufacturing side, the cost reduction comes from the following compromises:
  1. Moulds are made from hand made masters
  2. Manufacturing is done in China, with quality control from Ian. Several iterations have been done on the layup to reach the right stiffness and quality 
  3. More work remains to do during the assembly as will see later
 So as a result, what do we have in hands ? 

I always look first at the wings, as it is the main component. Willow wings are nicely made, with a clean finish. The version I have is the D-box carbon which means this is a glass version with a extra carbon layer in the inner wing, going from the leading edge to the spar. This means that you don't see the carbon clothes, but you feel it as the wing skin is strong under pressure. The spar is using carbon socks as we can see from the servos holes. The servos bay is reinforced with an extra layer of carbon, to avoid deformation when installing the servos. Brass horns (much better than cheap horns made from epoxy plate) are in place, and "epoxy/micro" wipers are nicely made along the wing. Clevice exits are already drilled, wich is a good point as I hate to do it usually.

The fuselage is full fiberglass, the absence of carbon reinforcement is compensated by the diameter of the boom. No worries, it is 2.4 Ghz friendly ! The fuselage arrives in 3 parts. The rear part, with a sort of Bowden Cable System in place for the elevator that is working smoothly, the inner nose, and the nose cone.

The tailplane, in one part, which is screwed on the top of the fuselage with 1x 3mm and 1x 2mm screws. Epoxy/micro wipers are done on the tail. Remains to do the builbing and installation of the elevator control horns. Then you find in the kit the carbon joiner (section 20mm x 12mm, 6° dihedral), a long servos tray in plywood, a ballast tube, and a small plastic pocket with the servos covers, the clevices, the ball clevices for the tail, and 4 couplers for the elevator contol rods. in option it is possible to buy a 3° dihedral joiner. 

Overall quality is fine. The finish is clean and the fit of the different parts together is good, which gives to this Willow a good ratio quality/price.

Here are the weight of each element:

  • Left wing: 660gr 
  • Right wing: 648gr 
  • Tailplane: 95g 
  • Fuselage (including the inner nose): 413g 
  • Joiner: 59g 
  • Total: 1875g 

What is missing is the assembly manual, but this should be resolved soon by a online manual. In any case I will provide plenty of information during the building, so you just need to follow my assembly log.

Stay tuned !


1 comment:

  1. it is weakest point 2 part fuselage nose cone?

    ReplyDelete

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