My electric Chrysalis weighs 47 oz rtf.Powered with a outrunner it will climb out of sight in 1 min, but without hitting any lift, I will be landing in 3-4 min.

My cg is 4.625 behind the L.E. A spectra,Aspire,can out fly the duration of my plane almost every time. My aspire weighs 8 oz more. I love the Chrysalis but I must get more non-thermal flight time out of it. I have 1/8 washout in each wing panel now, but I think I had more flight time when I had 1/16. Please advise,I purchased 2 more kits at Toledo this year and I have to get them to stay up longer. What are your suggestions? This is my second summer flying this plane and I have been flying and building for 55 years. We can't use Poly's at the club contests.

From : Don Stackhouse

This is a perfect example of why there is no single "best" wing loading, or area, or airfoil. What matters is the combination, and how they work together as a team.

First of all you have to get the weight down. The Chrysalis was designed around the idea of lots of wing area for good visibility and decent weight-carrying ability (within reason), but using a low-drag, "high speed" airfoil to get good penetration without needing to fly at a high wing loading.

By comparison, the Aspire has a high lift airfoil, so it will float reasonably well even when very heavy, but will not penetrate as well. It takes gobs of weight to make the wing loading high enough for that airfoil to go fast, and because the wing span is still the same, the induced drag will eat up all your performance, particularly at low speeds.

My own electric Chrysalis 2-meter with a 7-cell RC2000 nicad pack weighs about the same as yours. It penetrates extremely well, but the thermalling performance and low-speed "float" are definitely off a bit. With a 2000 mah 2-cell Li-poly pack it weighs about 10 ounces less, still penetrates very well, but thermals much better.

So, assuming you don't have a construction problem contributing to the weight problem, and the entire problem is too much battery weight, you have a couple of options: 1. Talk your club into joining this century and allowing Li-poly batteries, or... 2. use some smaller nicads.

You need a 2000 mah 15 C rated Li-poly to adequately feed 25-28 amps of current into one of these brushless motors. In the process, you're carrying around enough battery capacity to give you about a dozen climbs to altitude on one charge. That's great for sport flying all afternoon on one set of batteries, but it's just some more extra weight for a contest situation where you can recharge after every flight.

A nicad can handle far higher currents for a given size. You don't need to haul around big nicads. Even if you're pulling 32 amps or so, in a one minute run that's still only about 533 mah. Even throwing some cushion on tom of that for inefficiencies, etc., you should still be able to get by with 800 mah or less.

NiMH cells can't handle as much current as a nicad, but they weigh quite a bit less for the same capacity. There are some high-current 1300 mah NiMH cells that might be a good fit for your application.

Also, if you're running a separate battery for the radio, get rid of it for contest use and use the BEC on the speed control. In a sport model you need a separate radio battery because multiple un-timed motor runs make it impossible to predict how much "juice" is left to run the radio. However, in a contest task you have a specific motor run time and a defined task time, so it should be fairly easy to make sure the motor batteries are sufficient to power the radio for the entire task window.

There's a tradeoff between washout and performance vs. handling. With less washout you get more performance, but the plane will not fly itself as much in the turns; it will expect more input from you. For an experienced flyer like yourself, it should not be an issue. Go ahead and experiment with less washout. However, that will give your plane small improvements in performance, not the big jump you're looking for. For that, you need to get that weight down. Mine with a 2000 mah 2-cell Li-poly and 270 mah radio battery weighs about 37 ounces ready to fly. Joe's has a 3-cell Li-poly (no radio battery) and a smaller Axi motor and smaller prop, gets fantastic climb performance, and only weighs about 35 ounces. Get yours down to those sorts of weights and I think you'll find it's an entirely different bird.

Don Stackhouse
DJ Aerotech