by Pierre Rondel

INTRODUCTION

Aerobatics has always been very popular in France. Several competitions can be found in each year's calendar, including both slope and aerotow flying. French manufacturers all carry one or more aerobatic planes in their product range.

Airtech, one of the major sailplane manufacturers in France, recently introduced the Psycho, which can be considered a smaller brother of the Jedi, a 2.65 m glider that is very popular in our country. The Psycho has a smaller wingspan, different airfoil (S6061) but the same general look. So, let's have a look on this new kid on the block!

 

The Components

The whole kit is really good quality. The wings (foam/veneer) are superb and have the flapperons pre-cut and articulated under the skin with a special nylon ribbon. A balsa stick is inserted in the foam core before pre-sheeting to properly close the flapperon and the wing to improve the rigidity in torsion. Wing tips and leading edge are in place and pre-sanded.

The fuselage, which is available in a choice of 7 different colours, has the snake outers already in place, the tail plane crank in place with piano wire already connected, the wing alignment peg holes already done and the fuselage joiner tube location marked. The carbon canopy is already cut to shape and the all-moving tailplane supplied is the same quality as the wings.

Accessories such as the plywood servo tray, 10 mm carbon joiner, pre-formed balsa block for the rudder and stickers are also supplied, as are building instructions, in French...

 

Building

The time needed for the construction is between 10 and 15 hours, which is short for a non-moulded plane. As usual, I started with the fuselage.

Fuselage

What is noticeable on this kit is that all the alignment holes or location marks are already done for you, that guarantees a perfect final geometry of the plane and of course speeds up the assembly. Additional holes are however necessary behind the joiner tube for the fixation hooks that keep the wings in place with the aid of rubber bands, and for the servo connectors.

The servo tray is already cut-out with holes for standard size servo. I fixed it in place with rapid epoxy and then added fibreglass (110 g/dm2) which juts out on each side to improve the fastening. The joiner tube is then placed in the fuselage with epoxy and micro-balloons.

The fin is closed with a balsa fin-post and then reinforced outside with fibreglass.

The rudder is a pre-formed balsa block, just needing a little sanding to prepare the surface and round off the angles before covering.

A small piece of epoxy board (printed circuit board) shaped and inserted in the rudder using rapid epoxy makes a simple but efficient control horn. The rudder is then hinged using three plastic hinges and a long piano wire provided in the kit.

 

Wings and Tail

Even though these wings are not moulded only a little work remains to be done.

It consists of enlarging the holes to install the wing servos (Gr3341 in my case), extend the cut on the underside of the ailerons with a mini-drill (3 mm) and make sure that the ailerons move freely.

The next step is to install the alignment pegs (a piece of 3 mm piano wire) in the wing root with rapid epoxy and installing a small hook to keep the wings in place just behind the wing joiner tube. The aileron control horns are cut from epoxy board, partially inserted, then glued with rapid epoxy.

The only thing to do on the tailplane is to finish the root by sanding it to obtain a perfect fit with the fin section. I then applied a little epoxy/micro balloon mix to the root to finish it properly and cover any exposed foam.

Finally, a last quick sanding before covering is needed, but it takes only few minutes to do it, including the final cleaning with the vacuum cleaner, followed by a stroke of the hand, which is a amazing tool to evaluate if the result is good or not!

Covering

Airtech provide, at a reasonable price, (or as an option with the kit: 2 colours, one for the underside, the other for the upper side) a covering material that I have used for several years and that I strongly recommend to everybody: http://www.oracal.com/

It's a vinyl adhesive tape (50 cm wide) and the exact colour of the fuselage. The advantages of this covering material are numerous. It is very quick to use, less than 1 hour for the two wings, it's very strong, long-lasting and the weight is reasonable.

I'm so enthusiast that for 5 years now I have not used any other covering materials! Kevin asked me to prepare a technical article about this subject. So stay tuned! (Strong, cheap, long-lasting, easy and quick to use - all words I love to hear. KN)

I also used vinyl adhesive tape for the decoration. I wanted an extremely flashy decoration but easy to cut (I use a Roland cutting machine interfaced with CorelDraw software).

The difficulty is to assemble the different colours correctly on the support paper before transferring all the decorations to the wing. I think the result is good, isn't it?

 

 

Radio Installation

As I said before, I choose Gr3341 (Graupner www.graupner.com ) because they have been designed especially to be mounted horizontally in the wings. They are screwed onto small wooden blocks and are easily removable.

Wing servo connectors are the Multiplex grey type with the connections potted in hot glue after being soldered. The hot glue does a great job of protecting the wires and can be removed very easily with a cutter if something happens or if you want to re-use the connectors. Hot glue is also perfect because there is no chemical reaction with the wire insulation as can happen with silicon glue for example.

The aileron pushrods are made with 3mm threaded steel, aluminium tubes and metal clevises.

In the fuselage the installation is very straightforward with the servos in tandem, a 4 x 1800 mAh battery in the nose and the receiver between them. I used a Graupner C19 9 channel receiver and Multiplex Europa BB servos for the elevator and the rudder. You can use any of the standard servos available on the market since space is absolutely not a problem (that's a real change from the traditional F3B/F3F moulded planes I usually build!).

 

Step On To The Scales!

It was a bad surprise to discover that I needed more than 200 grams of lead in the nose to obtain the correct CG of 90 mm from the leading edge, just behind the wing joiner. However, my fuselage is pretty heavy (but indestructible) which explain this extra lead in the nose.

The total weight is 2 Kg so the wing loading is around 50 g/dm2. This is a little bit high for the glider size.

I gave my feedback to the manufacturer who has now modified the fibreglass layout of the fuselage to save around 75 g, mainly on the rear part. A new servo layout has been also adopted. These modifications are now on all Psychos produced.

 

Flying

I had the chance to fly the Psycho in all types of conditions during the spring season in the Alps. To give you an idea of my background in aerobatics I've previously enjoyed such models as the Axel, Jedi, 2.8m Roedelmodell Fox and the Voltij.

In light conditions the Psycho is pleasant. The use of the flaps gives more lift and the dihedral greatly facilitates thermal turns, but the sink rate (due to the wing loading of around 50 g/dm2) means it doesn’t compete with lighter plane. You have to compensate with a better flight strategy.

However, note that with the modification that the manufacturer has now applied to the fuselage moulding performances should be much more interesting. I recently met a Psycho owner who has a lighter version (at 40 g/dm2) and he told me that he was very pleased with the thermal capabilities of his plane.

Anyway, the Psycho becomes really interesting when the wind blows a little bit more and that you can start to think about doing aerobatics.

Words that characterise the Psycho are, smooth, inertia and stability. This is THE plane for "academic" aerobatics, meaning it will execute all the figures as they are described in the school manual!

The plane is very responsive and consistent on all axes, without being too nervous. Rolls and 4-point rolls are very easy, even if the roll rate is not demonic. High speed flicks and spins are nice too. Because of its inertia vertical manoeuvres are a piece of cake. Loops, inside and out, vertical eights, cuban eights.

I like very much to chain several (up to 10!) stall turns together along the edge of the slope, then to finish with an inverted exit and a half roll. The psycho is just perfect for such exercises!

Once again, the dihedral, which could appear as an enemy, is in fact an ally! It doesn’t affect the horizontal manoeuvres and allows the intended trajectory to be maintained.

The Psycho also shows very good behaviour during inverted flight considering its non-symmetrical section. The compensation (down of course!) is minor and the speed stays reasonable. I already flown more than 30 minutes of inverted flight without any problem.

The only concern I have is about the knife-edge flight. The side area is good but not sufficient and not well balanced between the nose (too short) and rear part of the fuselage to maintain correctly the plane in this position.

Landing with flapperons up increases the sink rate but does not decrease the horizontal speed much. To slow the Psycho down (sounds like a line from a cheesy horror movie! KN), it's necessary to add some compensation to raise the nose. Don't hesitate to do several attempts if you are landing in a small area.

I prefer to repeat the approach and land the plane safely than landing the first time but damaging the plane…

To finish the flight test I had the opportunity to lend the plane to some friends of mine during a flying session; they refused to give it back to me so I consider that they enjoyed the plane…

 

 

 

 

Conclusion

To summarise, I would say that the Psycho is really a good aerobatic glider that I definitively recommend to beginners up to intermediate level pilots. The kit quality is at a top level, and you won’t have any headaches during the construction. The construction is well thought out with absolutely no bad surprises, a point that I always appreciate on a kit.

And for the others who are looking for thrills? Well, the Psycho is maybe too well behaved. Anyway this compact glider remains excellent value for the money.

 

 

 

 

 


Specifications:

Wingspan 2,30m
Wing section SD 6061
Wing area 40 dm²
Weight 1900 g (tested 2000g)
Wing loading: 47.5 g/dm2 (tested 50 g/dm2)

Price 1590 Francs (around £150 or $215)

Manufacturer: Airtech, 235 bis avenue de Grenoble, 38 180 Seyssins, France

Phone number: 33 4 76 84 07 54

Website: http://www.airtech-rc.com

Email airtech@airtech-rc.com

 



 
Any comments, suggestions ? Des commentaires, suggestions ? Send a message to Pierre Rondel.

Copyright © 2001 Planet Soaring - Pierre Rondel.
No commercial use or publication (e.g. on other www or ftp sites, print media) without a written consent.


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