Don handles some Basic Equipment for the Chrysalis glider...
I like to have everything on hand before I begin a project. I just received a Chrysalis. I will be using 5.4 gram servos and will either use the V-tail or the shortened conventional tail (both with lightening holes).
From : Don Stackhouse
The V-tail is lighter, and more durable because it does a better job of keeping the stab out of the grass during the landing slide. Handling between the two is nearly identical.
Lightweight covering is OK for the fuse, tail and outer wing panels, but use regular weight for at least the inner wing panels, they need it for torsional stiffness to avoid flutter problems. The best we've found in terms of the most stiffness for the least additional weight is transparent Monokote. Regular weight Ultracoat and Oracover (same exact stuff, just different labels) is tougher and more split resistant, but a little heavier and not quite as stiff.
I've ordered light RX battery packs in the past only to find I needed ballast in the nose anyway. If I build the Chrysalis as described can I use a 120 Mah Nicad or 170 Mah NiMh pack and not need ballast in the nose?
You will need to do an extraordinarily good job of keeping the tail light. Remember, way back when we designed the Chrysalis, an HS-80 was considered an ultra-micro servo, and the lightest receiver commonly available was a Hitec/RCD 535. Typical small batteries back then were 250 to 270 mah nicads!
If your receiver is good at low voltages, such as the Hitec 555, Berg and a number of others, then one good option to save more weight (assuming you can get the C/G without nose ballast) without sacrificing flight time is a 3-cell battery pack. Certain receivers, such as the old FMA "Tetra", have problems with this arrangement, but for most of the others going to a 3-cell pack will actually give you quite a bit more flight time per charge, as well as saving weight (or alternatively use larger cells with more capacity for the same weight).
Use glue sparingly and efficiently in the tail, and use medium C/A instead of thin (thin tends to soak in much more, requiring more glue and more weight). Keep a tissue or paper towel handy, and immediately wipe off any glue that squeezes out, before it has a chance to set up. Use lightweight Sullivan cables for pushrods (the ones with the thin yellow nylon tube casings). Of course you should also slim the fuselage as much as possible, as described in the instructions.
A really light Varathane finish will be lighter than film covering, but if you get even a little impatient it can come out heavier. You also give up quite a bit of durability without the film covering.
Even so, there will be a limit on how light you can make your Chrysalis, and more importantly, how light you SHOULD try to make it. In general, a lighter airplane will fly better than a heavier one, PROVIDED it was designed to be that light. Keep in mind that one of the roles we originally envisioned for the Chrysalis was as a cheap way for someone to try out the whole idea of hlg flying without having to invest in a bunch of new ultralight (for those days) radio equipment. It has a fair amount of extra wing area to help it carry the weight of "regular-size" (for back then) radio gear. That's also the reason for the wide fuselage option. That extra wing area we included for this purpose helps if you're converting it to Speed 400 electric power, but it can be a hindrance if you're trying to minimize weight. If you build an airplane far lighter than what it was designed for, you're likely to discover you've also built in a few compromises. In particular, the high speed performance and launch height is likely to suffer. For example, I know of a Chrysalis that through "heroic measures" (such as making new fuselage sides out of thinner wood and using thinner wood for the top and bottom planking) came out around 7.2 ounces. At that weight it had astonishing low speed performance, but it had terrible penetration.
OTOH, our Spectre series HLG's were typically under 6 ounces built stock per the instructions, one version could be built under 5 ounces without getting exotic, and all of them had world-class performance at all regions of the flight envelope, including high speed. This is because they were designed to fly well at that extremely low weight. Weight is a design parameter, just like planform, incidence, and airfoil characteristics, and all are important factors in the design process.
I know you like to have everything on hand before you begin a project, but in this case, because there are so many things that can't be determined accurately till the model is finished, I recommend that you wait on buying a battery (and on permanently mounting the servos) until after you can do a C/G check on the rest of the assembled model.
Don Stackhouse
DJ Aerotech
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