Line tension.....or lack therof.

Ron, grab the plane by it's leadouts and hang it in front of you like a plumb bob. Take note how the fuse is parallel to the ground. You certainly want the nose pointing slightly to the ground. This is where leadout placement is critical. Your leadouts are probably non adjustable and permantely fixed. I'm just explaining why this is important. I don't follow ANY plans when it comes to the installation of the tip guides. I generally tack glue them with CA and do the above test. Most of my full size stunters have adjustable leadouts. Sweeping the leadout guides forward makes the plane yaw inboard towards the pilot. Moving the leadouts back, points the nose outboard. In the event your plane is already pointing slightly nose down while hanging, I would look at other issues. Speed is important. I use no rudder offset and it's absolutely not needed and it may just be slowing the plane down due to the plane yawing outboard. Tip weight is really only important on take off. Once the plane is flying, speed takes over and keeps the plane out there. Too much weight can hurt the plane in maneuvering causing floundering especially when the plane goes into a loop for instance. On the downside it can cause the plane to bounce. Your weight in the tip sounds correct. The wing may have a slight twist in it.

I would certainly take the plane while sitting in a chair and place it nose down between your legs and sight the trailing edge to the leading edge. If the inboard wing panel is up, it could be causing the inboard wing to tilt downwards. Twist the inboard wing down and reshrink the covering. If the outboard wing is down, it's causing the same problem as it may be lifting the outboard wing into you. Twist the outboard up and reshrink. After any covering shrinking, sight your trailing edges for any bowing and fix. This can be tedious but it's well worth the effort. I see Rusty and I were typing simultaneously so I apologize for any repeats. Another thing we do is to cut out a piece of aluminum can. Cut a tab about 3 " wide X 1 1/2" use clear packing tape the tab onto the bottom of the trailing edge with about 5/8" hanging into the air. Keep the tab straight and fly. Check for tension. If needed, bend the tab up slightly and re fly and check for tension. It works well and can be done at the field quickly. Ken

Another common design factor for line tension used in building was to have the inboard wing slightly larger than the outboard wing panel. This is easily done on a profile simply by sliding the fuse over to the outboard side a bit. The inboard wing is technically flying faster than the outboard wing due to the smaller radius of the circle hence more lift is being generated. This allowed for less tip weight supposedly. Many large full size stunters have the outboard wing shortened by one rib bay. My Yak-9 which was a Sterling Kit had the profile body offset by a 1/2". I've had this work and I also had some planes that I questioned if this was causing problems. Ken

I don't know anything about control line but all airplanes have this in common: if your wings are warped and the warp causes the plane to roll away from you in straight and level upright then that same warp will cause the plane to roll into you in straight and level inverted. Might be worth looking into.

Good luck,

Bob

Ken Cook wrote: Another common design factor for line tension used in building was to have the inboard wing slightly larger than the outboard wing panel. This is easily done on a profile simply by sliding the fuse over to the outboard side a bit. The inboard wing is technically flying faster than the outboard wing due to the smaller radius of the circle hence more lift is being generated. This allowed for less tip weight supposedly. Many large full size stunters have the outboard wing shortened by one rib bay. My Yak-9 which was a Sterling Kit had the profile body offset by a 1/2". I've had this work and I also had some planes that I questioned if this was causing problems. Ken

Not to mention the countless hours spent, down through the decades, as Rednecks stared at their carefully built work of art, wondering HOW they managed to build one wing longer than the other !!!!

Kim, I must be a redneck. I'm guilty of what you stated and I've done it. I glued the wing in upside down making the inboard shorter. You never realize this when the glue is drying. It's always the next day after it had plenty of time to set. I think we've all been there and done that kinda stuff. Ken

Yeah...thus my policy for staying out of the shop when I'm tired !!!

There WAS that ugly incident, back in the 80's when I built a Ken Willard "Poolboy" flying boat fuse UP-SIDE-DOWN, priding myself on the precision cuts and squareness of the frame the whole time!

If the plan was drawn before 1981 and called for 3 pennies then you need to use pre 81 pennies. New pennies are zinc and are lighter than the old copper ones.

Holy Cow gentleman. You guys gave me plenty to think about. I will go over each and every thing mentioned here.

I will check back in with an answer. Funny thing is I put 3 tanks through the Baby Ring Tonight and it flew beautifully! loops were uneventful. Wind was a touch calmer this evening.

It's frustrating......

cribbs74 wrote:...Funny thing is I put 3 tanks through the Baby Ring Tonight and it flew beautifully! loops were uneventful. Wind was a touch calmer this evening.

It's frustrating......

Uneventful loops are good, glad to hear it. You're evidently getting more proficient, not as much at the mercy of the plane. Show it who's boss.

Kim wrote:

Ken Cook wrote: Another common design factor for line tension used in building was to have the inboard wing slightly larger than the outboard wing panel. This is easily done on a profile simply by sliding the fuse over to the outboard side a bit. The inboard wing is technically flying faster than the outboard wing due to the smaller radius of the circle hence more lift is being generated. This allowed for less tip weight supposedly. Many large full size stunters have the outboard wing shortened by one rib bay. My Yak-9 which was a Sterling Kit had the profile body offset by a 1/2". I've had this work and I also had some planes that I questioned if this was causing problems. Ken

Not to mention the countless hours spent, down through the decades, as Rednecks stared at their carefully built work of art, wondering HOW they managed to build one wing longer than the other !!!!

Kim: that quote has to make it to the hall of fame for quotes of the day. +1. happydad

Fantastic thread boys.
The old Paw'ed Spit I inherited some time back is built
Kinda off centre somehow. I think it's a Sterling kit
Which I thought must have been assembled
incorrectly, but I guess not.