EPP High Performance Thermal 1.8 Meter Sailplane

OBJECTIVE: A durable high performance thermal (and some what all around) ship that I am not afraid to launch in the sketchiest of conditions or worst of flying sites. I want something that I can bang around, yet still have a good performance envelope. Also discus launching is in the back of my mind... This is the shape I think I am after.

This is my first "scratch" built plane, however I "cheated" and used a wing kit from Dave's Aircraft Works. I used the wing from his I-26 "2 Meter" thermal foamie ship. I say "2 Meter" because it's really 71" or 1.8 meters... The DAW wing is a straight forward "plank" wing with LARGE ailerons, a VERY complete wing kit for the price! I modified this wing in the wingtip area and in the glassing of the joined area, other than that, pretty stock.

I wanted to use Coroplast for the tail feathers even though it would weigh a little more. The challenge was how to secure them, as almost nothing sticks very well to Coroplast. I also wanted the tail feathers easily removable so I could swap on a discus launch tail with a larger vertical tail surface area.

I am using a pod and boom design to minimize weight and ease replacement/modification of the over all length. My goal is to keep it under 30 oz.

Click on the thumbnails to ENLARGE.

I started on the tail first - here is the beginning of the hardwood and CF frame. Here is the pretty much completed tail section. This will slide onto the CF boom. One way to lighten up the ailerons!
Here I'm inserting a solid CF rod through the wing tip for added strength. This is a DAW wing kit almost ready for the other half. This is the CF plates to beef up a potential throwing peg should I want to discus launch it.
I choose to cover this wing with 3M 77 adhesive spray and packing tape since mods on a prototype are inevitable. I thought I'd cover the ailerons with a darker trans orange monokote. I use the 3 opposing hinge method followed by a full length top hinge - indestructible!
Here is the finished wing - pretty nice for packing tape! I used a heat gun to shrink it. Next I cut and shaped the nose pod. I made cut-outs for the boom and wing mounts. Here is a view of the boom channel and wing mountings installed.
I constructed these CF and hardwood sub-frame parts to hold the wing to the boom and have a place for the tow hook. Wing installed - the tightness of the wing screw pinches the boom and keeps it in place. Here is an overview - getting pretty close to what I had in mind...
Next I cut out made the cut-outs for the radio equipment and rud/ele servos. The servos are mounted against the walls with 1/8" of foam wall to spare. This removable block will make for EZ access yet hold the servos firmly in place.
I made sure I had enough room for the Rx and battery pack, then assembled the pod and covered it with strapping tape, then packing tape. Since I needed a bit of weight up front I used a nice big 1800 mAh NiMh battery pack. The Rx is HiTech 555. Here is the finished "Orange UN-crush-able"
Belly shot... Floating around in zero lift conditions off the hi-start... I'm getting used to the colors!
Camera in left hand, Transmitter in right hand...

Well, the finished plane came out at 33 oz. ready to fly, that includes 1.2 ounces of lead in the nose to correct the CG. This could easily be removed if the tail feathers were balsa and I used a thinner and/or tapered boom (this one is THICK!)... but I did want to build it to take the bounces! I figure I could easily make one under 30 oz. if I had the boom of my choice

Test flights have been great, just waiting for good flying conditions to run Orange UN-crush-able through the paces and I will give a full report!

Well, I had my first semi-thermal flights today. It was on a mellow slope and very light conditions. There was just enough slope lift not to sink out, I really had to scratch, but the "Orange UnCrushAble" hung in there. I finally picked up a few thermals and before long I was up 200-300 feet. Once at that altitude it was much easier to catch thermals and so I was able to stay up for 10 or 12 minutes, I then wanted to do some loops and rolls to see what she could do.

Very nice! I could do VERY tight loops and the roll rate was pretty good as well. The rolls were not very axial so I will try some differential in my ailerons, that seemed to make a big difference on my Art Hobby Bore. This thing circles very well! once you get it turning it is very neutral and circles pretty flat. I started using a little rudder in my turns and they were even flatter so I programed in some rudder/aileron mix on a switch that I can turn on/off. I am very pleased and I have already had a few mishaps, all without any damage what so ever! My buddy "landed" his Zagi on my tail feathers while it was on the ground and all it did was knock the coroplast tail feathers out of position, which I just slid them back onto their rods. Cool, that was what I thought would be the weakest link and it survived a smack - nice! Well, I already want to build another, maybe a 1 meter!

Good flyin'

You can check out a thread I started on RC Universe here: http://www.rcuniverse.com/showthread.php?s=&threadid=95189&forumid=35