I am just finishing up a Giant Scale Planes Swallow 90 pattern ship. I have a Super Tigre .90 in the front end with a header pipe to a macs 90 size quiet pipe. Servos are in the wings and radio bay in the openings where they go with no modification. Rudder is pull pull. Elevators are driven by a single carbon fiber shaft with 4-40 ends. A sullivan tail wheel is at the back and a tru turn spinner up front. The plans recomend balance point about 25% behind the leading edge. Without battery this thing is balancing 8 inches behind the leading edge of the wing! Even when I put 1800 ma's of nicads, which I never use, I always use nimh batteries, taped under the fuel tank in front of the gear I only get a balance point 6 inches behind the leading edge of the wing.

Somebody's gotta help me here. I have never had a plane come out so far out of wack. Do I have to go mount a 1.20 in the front end of this thing to get it to balance? Does it fly in the real world with the balance point further back? What do you who have experience with this plane have balance wise? Is my power plant excessively light or what? I'm not interested in flying a plane with a pound of useless lead in the nose. If I have to add that much weight it should at least be producing power. But I really want a .90 size plane. I'm not into 1.20 and bigger power plants. If I have the wrong plane, I'll just sell it.

Thanks,

bob branch

Bob, I flew my Swallow with CG 165 mm back from LE at fuselage, and it handled very well at that point. I did try a bit further back, since some guys recommended back as far as 180 mm, but for me that gave too sensitive an elevator. There are a lot of guys that like a two-stroke 1.20 on this plane, but a piped 90 should offer ample power. The 25% CG recommendation is not to be taken seriously.

It's not the wrong plane, so don't sell it. Swallow flies beautifully. I crashed mine in a moment of distraction, but got another and looking forward to putting it up again.

I hope you're setting up low rates on elevator. I had trouble getting smooth landings at first, had to reduce elevator throws twice, add expo and move CG forward before it would behave well on landing. Elevator was at +/- 9Ëš when I was finally happy with it.

I will not have computer access for a few weeks, so further questions will have to be answered by others. Good luck with your plane, it's definitely a keeper.

I definitely concur w/ Majortom. I've got a Saito 91 on mine and it balanced perfectly w/ the battery right behind the tank. I've got my cg at 175mm behind the LE.

Check out the other threads on the plane and beef it up in the narrow part of the fuse, and in the landing gear plate. I had an engine flameout on mine a couple weeks ago while about 15' up and slow on the upwind end of the runway.... Had no choice but to turn and land downwind in rough grass. When the gear caught in the rough grass it ripped the landing gear plate out, punching a hole in each wing. The plane then rotated forward, slammed the engine into the ground, broke the motor mount which allowed the engine to break the cowl, and also broke the fuse at the narrowest portion in the cockpit area. Not a good day. It is very repairable and I've got it about 1/2 way back to flying. If I were you I'd glass the inner area around the gear plate and also glass the entire area in the cockpit/radio tray area. I know it comes glassed in this area from the factory, but some more would definitely help alleviate breakage on a rough landing.

I also replaced all of the hardware w/ adjustable horns, swivel ball links, Dubro pull-pull, Sullivan tailwheel, and Tru-Turn spinner.

There is a GREAT online build blog on a UK site with a ton of hints. If you can't find it, PM me and I'll get it for you. It's bookmarked on my home computer and I'm out of town until the weekend.

Enjoy it!!

tim

Thanks guys. That cg is within the realm of possibility.

Have done the other mods you mentioned. Yea, I toss all the std hardware and use decent stuff. Do it on everything I buy.

Could someone share their method of antenna routing?

bob branch

The antenna on my Swallow is routed inside a Sullivan yellow pushrod which is in turn glued inside the fuselege side and goes to the tail.
The cg is 7" from root leading edge. I also used the hinges provided by the kit manufacturer with no problems.
I am flying my Swallow for almost a year now.

On the swallow the correct cg is 165-175mm not the 115 mm that the instructions specified. The two i built took no weight with a ys 91 and a 110. to get it to balance at 115mm it would have taken 12 ounces of lead. I used a hayes 16 oz. slimline tank to mount it closer to the cg. Hopefully you did'nt use the supplied hinges. if you did i would say to just cut them out no. The wheel pants will last about 8 flights on a grass field.

Dennis

Dennis

Thanks for the info. That is where mine came out as well. I fly grass fields only so I never even consider wheel pants. They are just not worth the effort. Once I finish a plane I want to fly , not rebuild constantly.

Yea, replacing the hinges is a no brainer. With slots cut in just about all arf's now days, why would anyone put in a CA hinge when a kleet or other similar hinge is so easy? Just hit the slot with your slot cutter to enlarge it and drop it in.

I have noticed alot of pattern planes use prop pitches that area quite a bit higher than we use on scale aerobatic planes. Could someone explain the advantage to this? I am assuming it has something to do with flying on a pipe. How do I get an idea of what pitch to use. I normally use a 13X6 on my ST. .90's in a scale aerobatic plane without a pipe.

bob

The high pitches keep the noise down. on the 91 fz i ran a 14-10 and on the 110 i ran a 15-10. both engines were spinning around 9000 rpm. Normally i run Bolly Wheel pants. Expensive but they last. I don't know if you want to try flying pattern. But there are three contests this year not to far from you. one of them is at the radio control club of detroit. ww.rccd.org Another one is at the Midwest field. At 5 mile and beck in northville. And another one is at the signal seekers in westland. The swallow makes a nice pattern plane i used one in intermediate for two years.

Dennis