|
|
|
JART Set-Up
– CG –
60mm from LE at wing root (not fuse joint) - start here and adjust to taste. If you are using the designed airfoil for the stabilizer, you have a fair amount of leeway here. Some of the expert pilots are running the CG back to 65mm or even 67mm.
– Throws –
Ailerons:
2cm up and 1.5cm down
Elevator:
1cm up and down
Lately, I've been going with slightly more symmetrical aileron throws, but each plane/pilot is different so it really is necessary to "adjust to taste."
|
|
|
Flying a JART is a rush. I know, I know, of course I would say that since it's my design. But really, I'm telling you, it's a rush. It's fast, smooth, agile and surprisingly stable. At my home slope it carries energy in the half-pipe like nothing I've flown at comparable weight. It flies inverted well and will do any inverted maneuver, including nice clean outside loops, if flown carefully in the right conditions.
The JART ain't a lead sled at the standard build of about 50oz auw, but it'll keep up with the heavies in big air while remaining far more nimble. And it doesn't need monster lift to stay in the air. In fact, it's very fun to fly in medium lift. I've ballasted it to about 65oz and it definitely increases the speed and penetration, as you'd expect. But there just aren't that many days when you need that kind of weight. At the standard auw it flies in a fairly wide variety of conditions and it's always fun.
All-in-all, this plane does exactly what it was designed to do: combine my favorite aspects of PSS and 60" flying.
Nuances
At one point, I began using snapflap to improve the turns. It seemed effective so I tried it for inverted flying as well – not so effective. The plane wobbled a bit and energy retention for inverted turns was not improved at all. After many hours of playing around with snapflap I've decided I like no trailing edge effects at all. Just a nice solid TE gives me the most consistent performance - I find it's the best way for me to predict what the plane will do in a given situation.
The JART does have its quirks. Because there is no dihedral it doesn't self-correct, even when flying upright. And the 6062 airfoil doesn't bank and yank, even with the snapflap – you have to let it cruise through the turns. I would describe it as a "soft" airfoil – introducing elevator never causes the plane to bounce, instead the airfoil seems to need a moment to settle into whatever attitude it's in. A liftier airfoil would certainly allow the plane to turn more tightly, but you'd give up some of the inverted performance and neutral handling. And a touch of dihedral would make it tend to corrent a bit when flying upright, but where's the sport in that?
Special Note: HEAVY PLANES
Launching a heavy is one of the most difficult things in slope soaring. When you look at my videos, you'll see that even with my 56oz JART, on a 450' seacliff in 20mph wind, I let the plane drop anywhere from 50' to 200' before I start leveling out. It takes balls, but it's actually much safer than trying to fly straight out and risking a stall. Add 20 oz to the weight and the whole affair is exaggerated. Point the nose down and let her fly.
Adding more than 8 or 9oz of ballast in a plane like this is asking for trouble – the inertia caused by the extra weight will overwhelm the structure, even on a good landing. Not always, but the more ballast you put in, the more likely it becomes.
Everything is more critical, especially CG. You might be able to use an aft CG on that inland slope, but when you throw a heavy off of a cliff, make sure your CG is conservative.
I don't fly the JART with ballast, regardless of the conditions. It's designed to fly in medium to high lift and my experience is that the more lift I have, the more I can do with the plane. Extra weight just detracts from the possibilities. She's like a dancer, strong and agile, but if she starts to add weight she's likely to get hurt.
|
