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Ritning: And_Now  
Ritningen är skapad av David Theunissen
'And_Now?' (or 'White Thing' as we often call it) is a stunning little model, indoors or out. You can get exciting performance indoors on 7 cells and fly in 10 knot winds outdoors on 8 cells. 7 minute flight times are common with 300mAh NiMH's. The model draws a great deal of attention from both the general public and modellers alike. Need more convincing? Search the Discussion threads on the EZone. It's a more forgiving model than the Extra, and with its generous wing area handles lower power settings. The plane is a natural evolution from the PicoStick/LiteStick as most of the 'hardware' can be reused. It will give most people more than enough aerobatic capability although it is tame by comparison with the Extra and Nutta!
'Und_Nu?' is the original name for the model. It was designed by Michael Bohm and discovered on the excellent Klaustrophobia site (http://134.169.96.2/~modellflug/klaustrophobia/klaust.htm). My drawings include a few improvements to his brilliant design. The fuz is now based on the above-mentioned Pico Stick which is as light and simple as you can get. And with Depron flying surfaces, it only takes 2 hours to build and is extremely robust. It does not require the most hi-tech motors. It is a model which is really hard to beat. The model should weigh less than 170g (6oz). The wing area is 277 sq in which results in a wing loading of 3.1 oz/sq ft. I use 8x300mAh NiMHs, the GWS R-4P Rx (with half the aerial removed), Schulze 08 ESC and 2 Hitec HS50 servos. You can add a working rudder but it is not needed for normal flight. The take-off run is about 1 inch off grass!
The motor used by most for this model is the '150' size available from GWS (the 'IPS' size used in the LiteStick/PicoStick/Tiger Moth). Multiplex, Alpha, and other makes are available and appear to be identical to the GWS. There are at least three motor options. The 'Carbon Brushed' (DC) version is the best with the 'Deluxe' (DX) a close second. Both have good magnets, similar power and are usually accompanied by gearboxes that have 2 bearings on the prop shaft (often labeled 'BB'). The 'Standard' version will work but don't buy it if you have a choice (it has weaker magnets and bushes instead of bearings).
The gearboxes which come with these motors have many different ratios and your choice depends on the number of cells used. To keep it simple, buy either the 'A' (5.8:1) or 'B' (7:1) 'DC' version with 8 Nicad or NiMH cells. The cells would typically range from 120-180 Nicads to 280-300 NiHM's (NiMH's will normally give longer duration). The prop would normally be a GWS 10x4.7 or 9x7.
Two newer gear ratios are now also available. These are the 'S2' (3.5:1) and 'S1' (4.1:1). These suit smaller cell numbers and I have seen spectacular performance from an S2 on 7 cells. Consider the 'D' (9.6:1) ratio if you want to use 3 Lithiums. A geared Speed 280 is another option but the overall weight and wing loading will be higher. Although the easiest way to mount the motor is to push it on to the front of the fuz stick (as GWS have designed it to be done), the motor takes some abuse and usually breaks eventually if you crash into walls and things. A more enduring approach is make a 20x30mm 1/32 ply or 6mm balsa 'mounting plate' and to strap the motor to the stick with a couple of rubber bands. This gives it a bit more flexibility which also helps stop the fuz stick from breaking. A 'prop saver' where the prop is only retained with a rubber band is another aid to resilience.
The design is based on 3mm (1/8") Depron which is a very dense foam. This provides the perfect balance between flexibility and rigidity for models like these. Note that Depron usually has a 'grain'. The wing does not have to be preformed in any way if you use the natural curvature of the Depron in the right direction. Add two extra wing ribs at the ends of the spar if you go for higher power settings or find the wing twisting at higher speeds (remember it's meant to be a 'slowfly' model!). I list every source of Depron that I know of on my links page. I also have a small section here about some other uses for Depron. You will need a little Cyano to build the model, and copious amounts later if you crash as often as most of us do! 'Odorless' Zap is foam-friendly, as is 'Grip' cyano activator to speed up field repairs. Note that the occasional mid-air collision and inverted landings contribute to our normal attrition rate; the plane holds together exceptionally well under less arduous conditions. Even with our abuse, there are few components that Cyano can't repair in a couple of minutes.
Plans are in various formats but the 'pdf' version should be the easiest. The 'DXF' version is only needed for the CAD guru's. The pdf plans should print to scale on one page and most dimensions are noted for you to build one. The wing starts 60mm from the front of the spar. The dowels for attaching the wing are usually 5mm ahead of and behind the wing itself. Start with the CG about 65mm back from the leading edge of the wing and move back 5 or 10mm to improve roll rates, elevator sensitivity and inverted flight characteristics. Once you've crashed a few times and seen how resilient the model is you will also discover that most dimensions are not critical so don't worry if you need to change a few things. Don't bother beefing up the design to make it stronger; all you will do is add unnecesary weight. Email me if you get stuck!
Källa: http://www.flyelectric.ukgateway.net/
Ladda ner ritningen här: And_Now
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