jmrpb

For some time I have this thought – Build and fly a swept forward wing rc plane.

Swept forward wings have incredible performance at slow speed with high AOA (angle of attack) capabilities and are also very good at transonic and supersonic speeds. The wind tunnel results have demonstrated that.

This is because of the even ‘cos – co-seno’ function. In theory, if it would be executable, the same exact wing, with the same angle, the Swept forward wing would be better than the contra part wing with the same angle of swept back.

So, I’ve put my mind on it for some months ago and I’ve designed this aircraft which photos I also post. The photos were taken today, a cold Autumn morning.

It has a simple way of vectorial thrust, like some of your planes. It does almost any 3D manoeuvre that you can think of, with a very good vertical performance. And, of course, it is also very forgiven and stable if you want to. Most of the times, I catch it by hand.

The power system is the great secret for good low speed and high speed performance.

The specifications are:

Motor: Axi 2208/34 gold line;
Propeller: Graupner 9” 6” Slim cam (exactly 9” 6”, not the smaller ones like you guys use. This is because the 9” 6” is perfect for acceleration from slow speed and high AoA and also have great behaviour at high speeds);
Batteries: #1 Lipo 3 / 850 mA/h with 30C (also by Graupner);
Speed controller: Jeti 8A (yes; just only 8 Amps, but this is more than sufficient. With this power system I can maximize my flight times – 10 minutes with 3D and Acro performance or plus 15 minutes with gentle use of the throttle stick (this is, if you can control yourself with this kind of machine ).

The ailerons and the elevators are linked together by one carbon tube.

Roughly, the dimensions are:

Front to tail: 89 cm (overall length);
Front to leading hedge of the wing: 46 cm;
Wingspan: 66 cm;
Leading hedge swept angle (wing): 65º;
Wing trailing hedge swept angle: 55º;
The outer far part of the wing is: 13 cm (with ailerons);
Ailerons have: 8 cm;
Elevator swept angle is: 20º;
Dimensions of elevator (at widest point): 14,5 cm;
Dimensions of rudder (at widest point): 18 cm tall by 13 cm wide (at the bottom);
Weight: 320 grams or ~ 11 oz to ~ 12,5 oz range. Ready to fly (with this set up and battery).

The front part is made of yellow ‘polypropylene’ that makes it almost, and I say ALMOST, indestructible .

I hope that this brief description helps.

It does not have any kind of KF airfoil simply because of weight concern.

It looks great in the air and it’s guaranteed that you’ll receive all the attention of other RC fellow pilots!

José Bernardo
Lisbon, Portugal, Europe

jmrpb

Below are some pictures:

jmrpb

These are some aerobatic movies. Hope you enjoy it .

http://www.youtube.com/watch?v=3YDh8E4ezEU http://www.youtube.com/watch?v=8bJUjK_ZsFs

jmrpb

And another one: