The Next Step - Bigger is Better
Once you have mastered the basics of control line flying, it is better to go a little bigger. A larger model will not get you as dizzy and will be much more stable during level flight.
The SIG Akromaster or Flight Streak Jr. is a good model
for today's modern .15 engine, like an OS15FP. If you want to get
into a bit larger, go with the SIG Skyray 35. See the "Brett Buck's Starter
Package" configuration below. The Ringmaster is a good nostalgic flyer but
current production quality of the kits are not so good. I would rather build
a Carl Goldberg "Shoestring Stunter" or "Buster" if you can
find it. Most of these early kits were designed originally for a Fox .35, can
easily be powered by today's modern .20 or .25.
Unfortunately, the OSFP .20 for Control Line is no longer made. You can
currently order the OS 25 LA CL series from Towerhobbies.
If you have a modern OS 20 or 25 that was designed for R/C you can convert
it to C/L. Even if you leave it as an R/C engine, it still works well
for C/L. All you have to do is to tighten the throttle position opened.
Today's engine will turn a higher RPM than engines of the past. Therefore, you
need to go to a lower pitch propeller on these engine, so don't use the old
standard 10 X 6. Try an APC 9 X 4 or 10 X 4 propeller at about 11-12K RPM. Also,
Brodak has a new .25 engine that works well
in this application.
If you want to get into flaps, the SIG Twister is a good model. Many pilots in
the beginner ranks have advanced using a modified version of the SIG Twister
known as a "Fancherize Twister".
This was a version made famous by Ted Fancher in a 1985 AMA article. The major
result of the modification was to extend the tail moment 2 to 3 inch. giving the
airplane a better turning characteristics in corners. For a bit larger engine
such as .35 to .40 engine, the SIG Banshee is a great flyer if you shorten the
nose about 1 to 1 1/2 inches. I think this is a much better flyer that on Twister,
however most people complain about its appearance.
Brett Buck's Skyray
V.P.
PAMPA district X
Brett Buck, PAMPA V.P. of District X and who
ranks 3rd at the 2000 nationals, has been entering local contest and scoring in
the low 500's, with his OS20FP powered Skyray.
- SIG Skyray 35 with stock everything in terms of external shapes, with two exceptions - Chord of elevator has been increased to 2", and NO, repeat NO, rudder offset. No asymmetry. Very slight modification/repair to engine mount only to fill/cover holes from previous engine experiments*.
- Hallco 2-wheel R/C gear, cut in half and rebent to fit on profile fuse instead of flat bottom of R/C model.
- 3" Dave Brown Lite-Flite wheels
- Structure uses kit parts for fuse and tail. Wing rebuilt using 3/32 ribs, full at each station, with 1/2 square LE, 3/32 top and bottom TE, and spars of 1/2x1/8 balsa.
- Monokote wing/tail, K&B Superpoxy on fuse.
- Stock SIG bellcrank with stock (kit) music wire pushrod, in outside hole of bellcrank.
- Pushrod fairlead made from "Luxon" connector.
- Carl Goldberg "large" nylon elevator horn, with pushrod in hole 1" from hinge line
- Front leadout 1 7/8" from LE, aft leadout 2 7/8 from LE. Leadouts are not adjustable, rear leadout is "down" elevator.
- NO engine offset.
- Dry weight = 31.6 oz.
- "Tip weight" = 1.76 oz, determined by "counterweight method". This is not actually the weight in the outboard tip - it's the amount of weight that I had to put on the inboard tip to balance the airplane laterally about the center of the fuselage. I'm sure that the engine/muffler hanging off the outboard side of the fuse is a large fraction of this. But the method should result in repeatable results.
- CG = 7/8" from LE. This is only about 9.7%, Note that this is different from what I had previously been running. but it works awfully well there. It may not be optimal.
- Lines - .015x60 (eyelet to eyelet) stranded
- Handle - Fancher solid-contact type. Spacing 3 3/16", offset (from aft edge of grip to holes) = 2 3/8"
- That ought to be pretty reproducible. Just make sure you put the wing and tail
on straight, the rest of it is covered.
Brett
Tips on Building the Sig Skyray 35
|
You need a flat surface to work on. The Sig Skyray can be built on a piece of glass. Just use masking tape and wax paper over the plans. Also, the wing does not require any jig. The supports are built into the rib, so be careful not to cut them off until the wing is complete. The secret is to attach all of the ribs to the bottom spar first and do not glue it down. I glue the leading edge first by gluing the ends and then supporting center ribs. |
| The bell-crank system is one of the most important components. Make sure that the controls movements are free from friction and securely glued to the spar. |