Originally Posted by p9o1r1sche

Sorry for no pictures yet, but when I go to the field, I am alone. Just handling a new plane and flying takes my complete attention.
I should be able to have someone take pictures this weekend at the Mid-south Sailplane contest, where I will be competing in the RES.

Having recently taken up R/C I'm coming to Triple Tree Sat am (from Brevard) to explore what Soaring is all about. I'm a member of the Henderson County Flyers and will be sitting on the sidelines in a green & white folding lawn chair!! Hoping we might connect.

Hi Doug,
I can't see a PM link to your account. Send me a PM. My brother and I are fairly new to RC. I am in the Fletcher RC Flyers club.

Went to the Mid-south Soaring Championships yesterday (ALES and RES event). The X-RES didn't fair well on the winch at all. The wing immediately shattered, so I have a repair job now. I am not very experienced using a winch, so the problem may lie there. There was gusting wind 0 to about 12 mph, so I ballasted it up with 4 oz (all I could get in the fuse) and did some hand tosses to trim it out. Looked good in these trimming flights. I'll be sticking to the hi-start for a good while.

Sorry to hear about your XRES. I wouldn't winch this model without some mods. The biggest problem is the spar which is a 3mm balsa shear web with basswood spar caps. You could easily get separation with too much load. Not just in the middle but also where the joiner is. The basswood is fine (vs. carbon which is better) but you have to strengthen the shear web/shear web bond. As the design is now it is just a glue joint. I used thin CA and then applied white glue via syringe to make gussets. If I were making this for a winch I would add an additional cross grain balsa shear caps in the center panel. I would also integrate the joiner tubes into the spar. Then on the outer joiner I would use 3-4MM balsa ply vs. the 2MM ply used. Even after this you still have to be quite careful in launch with very careful tapping on a regular TD winch which are normally quite strong.

Oh also on the issue of ballast many of the German competitors are using 40-80 grams and not much more than that. 4oz is a lot for a model like this.

Good to see Hyperflight getting these in stock, ill be grabbing one once they arrive =)

Originally Posted by p9o1r1sche

Sorry for no pictures yet, but when I go to the field, I am alone. Just handling a new plane and flying takes my complete attention.
I should be able to have someone take pictures this weekend at the Mid-south Sailplane contest, where I will be competing in the RES.

Were you able to take any pics of this fine sailplane?

Still don't have pics of the plane before the winch incident. I took the ones below afterward. Being at my first contest and flying an event before the RES the same day kept me busy.
1) First is the cockpit area - battery goes in the nose, then the receiver (under the mass of wires), then servos. Under the wing is the ballast area and tow hook mount.
2) Adjustable tow hook.
3) Elevator pylon made from fiberglass. Its pretty tough - didn't break after all its been through.
4) broken wing spar next to the center rib. One can see the compression of the shear webbing.
5) Pic of tail assembly.

I have the fuse and tail repaired. Fixing the wing is next.

In general the shear webs should be vertical grain hard balsa . And perhaps some cf spar caps with Kevlar or carbon tow wrapping. Yeah, it is more work but pretty much impervious to winch launches.

Originally Posted by ray foley

In general the shear webs should be vertical grain hard balsa . And perhaps some cf spar caps with Kevlar or carbon tow wrapping. Yeah, it is more work but pretty much impervious to winch launches.

I agree with the shear web grain comment. It would be difficult for picture #4 to happen if the grain had been upright. Yuuuuge difference there.

I can't see any slippage between top and bottom. It's possible vertical grain would allow some, since it's weaken in that direction. Adding some very light dental-floss diagonal wrap could prevent that.

IIRC these planes are made to be light; very light. It's a shame about the winch, but I'm not sure these are designed for winch forces.

These models are designed for an 8mm bungee and a very long length of mono. The pulling force is also spec'd out in the rules.

I think just adding an additional vertical grain balsa shear web will make this model adequate for a winch. I bet it only adds 20G or so to the AUW.

I'm doing finish sanding right now. Zeller includes plywood leading edge templates to help you get the foil spot on. It's very helpful. They even give you a map on how to sand the elevator and the rudder.

As Bmwjoon says, these airplanes are not designed for all-out launching. Instead, the premium is on performance: getting to lift, and working it. For that, these 2-meter ships for F3B-RES are superb.

Yours, Greg

I'm almost done with finish sanding. I promise to post pre-covering detailed pictures of all the parts. I've just been too busy at work to do that sort of stuff here.

I did change how Zeller recommends installing the spoiler servos. It just seemed too complicated for me. Unfortunately I got glue into the gears of one and ruined it Oh well, wasted $7.

Also I changed how the wing tips are constructed. Their recommended method had what I thought was more structure / glue area than needed.

So far with all the wood, 4 servos, receiver, battery weighs around 300G which is light. After I finish sanding I may go back and add vertical grain 1.5mm balsa to the spar for at least 3-4 ribs.

looks like they use a full length web as sort of a jig for building the wing...nice idea but a few bays out from the center really should be backed up with vertical grain. looks like there is still plenty of room between the spars but gluing to the faces of the spars (back, front or both) might be better.

What are the actual dimensions for the spars? Are they spruce?

Originally Posted by jcpatrick

I agree with the shear web grain comment. It would be difficult for picture #4 to happen if the grain had been upright. Yuuuuge difference there.

I can't see any slippage between top and bottom. It's possible vertical grain would allow some, since it's weaken in that direction. Adding some very light dental-floss diagonal wrap could prevent that.

IIRC these planes are made to be light; very light. It's a shame about the winch, but I'm not sure these are designed for winch forces.

The picture is very helpful to see the failure of the spar under a load. It was compression that failed the horizontal grain, I see now why vertical grain is recommended... sorry about the pranged ship and thanks for the pics, I learned a lot from that photo -Steve