Hi, i just finished putting this arf together, and im a little baffled. I used an OS46AX as recommended by Kyosho (they recommend 46FX, but the AX is virtually identical in weight), put everything where they recommend it, and my plane is nose heavy. by something like 12 ounces. 12 ounces of Tail weight???? What is going on here? There is really no place to relocate the receiver and battery, so I guess Im stuck with lead. any idea why it would come out so off?
Brice

canopy2k,

Double check your method used to balance the plane. Biplanes can be a bit tricky to balance and the wording in the instructions often times is a bit difficult to follow. Adding 12 oz to the tail of a 40-size bipe doesn't sound right at all.

I used a Great Planes cg machine. I was a little off though, I didnt read the lead right. It was 6 ounces. 2 sticks=6 ounces. Thought it was 6 ounces a stick. I balanced it at 120mm based on reviews of the plane that 130mm was too tail heavy. The balance point is 120mm from the leading edge of the top wing, on the underside of the top wing. Heres a graphic of the CG from the manual.

If I balanced it at 130mm I would need even more weight. The thrust washer is exactly 120mm from firewall, so its not that the engine is way out there. Is 6 ounces too much or is that in the realm of acceptable???
Brice

(edit) I used mini servos in the wings instead of standard servos. The Servos are behind the CG. Could that be part of my balance issue? Perhaps these weigh so little the lead is needed to compensate?

Even 6 oz on the tail seems excessive, but I would double and triple check the balance then fly it. Let me know how it flies...I have a Saito 82a that may soon be looking for a home.

Yeah, I balanced it 4 times on the CG machine, then marked the cg with a metric ruler, and fingered it a couple more. It seems to be balanced just right with the 6oz in the tail. Im going to take it out to the field tomorrow AM and let the club expert have a look at it. If he says go, Ill go with it. If not, Ill work something out.
Brice

Right on Brice, good luck!

Canopy...I put the same plane together last month,....Tower Hobbies engine, (bought as a combo package, saved a few bucks)...used a GP CG machine, it showed me as being way nose heavy too, wasn't smart enough, (as you are) to ask a few questions before I balanced to Kyosho instructions....added 3 1/2 ounces to achieve recomended CG....heres what happened...I hope you get this before you go try to fly that thing.

sorry...screwed up that last post...here ya go...

http://home.dc.rr.com/maurie/Pitts%20Maiden.wmv

oops....screwed up again,....I'd forgotten,...I actually mounted an OS 46FX to the plane, took it off my ultra stik...as the pipe that came with the Tower Hobbies engine was too long to fit in the space provided on the bottom side of the fuselage, and I couldn't get it to run right with the muffler from the OS on it,..regardless, Kyosho screwed up big time in their instructions, do NOT go by them. Still haven't made repairs to this plane, as I've been busy working on others. The guy I had maiden flight the plane is an excellant pilot and was able to put the plane down with only minimal damage and is easily repairable.Please let me know what your solution is.

so, that being said, it seemed that yours was tail heavy even when it was picked up with the fingers at the end of the vid. hopefully the 10mm forward on the CG will be ok. This is what worked for a reviewer with MAN. He crashed the first one just like you with the 130mm CG
Brice

Good luck on the maiden flight canopy, let us know how it turned out.

Well. she flew! Balanced at 120mm she didnt fly very well... Lucky that I wasnt flying it or it would have been lost.. The pilot was excellent. Flew like a duck. Took of 2 ounces of weight and tried again. That just about did it. I think Ill pull 1 more ounce off. Balance point now, flyable is about 102mm. That is 28mm farther forward than Kyosho recommends. What the heck? Are they crazy or what? Where in the world did they come up with 130??? Must have been smokin crack when they wrote the manual. Well anyway, she looks real pretty up in the air. Ill get out this week and take her up myself.
Brice

Hey canopy2k,

Congrats on the maiden...I'm glad to hear it made it through its first flight.

About the balance...I bet they transposed numbers and is supposed to be 103mm!? Anyway, once you get it dialed in give us a flight report, if you don't mind. I'm still considering this bird for my first bipe. Thanks!

Hey.. this really is a pretty plane. I dont know if I would recommend it yet... Once I get some flights on it this week ill be sure to update you. If you do get it, I would start at 100mm CG and work from there. You wont hurt a thing with a noseheavy plane, but tailheavy! Watch out!!
Brice

hahaha......"smokin crack when they wrote the manual"....I'd have to agree with you on that one canopy......when you get it totally balanced out..let me know..I'll go with your specs, as I have the same engine in mine,....heres my maiden flight again, balanced according to the 'crackheads' specs...... http://home.dc.rr.com/maurie/Pitts%20Maiden.wmv

I dunno.......I built mine last year and still flies well with a Saito FA-56 with an APC 12X6. Balances ok at the recommended CG. It's only squirrely on the ground for take off....but once she becomes airbourne... she's one sweet flier. Very aerobatic and nice to look at. In the beginning....on landing she would cartwheel. No broken bones. I do have the landings nailed down now though...but every now and then it would still cartwheel....guess it's when the grass is cut or not etc or just my landing skills.
Hey....if you can fly this Pitts....U can fly anything...
Good luck and cheers.

after watching the video a few times, i wonder if the pilot was holding too much up elevator? if your like me? you may have added a bit more movement than recomended in the comic. i have only flown the kyosho pitts on the reflex flight sim, but if you hold in full up elevator at slower flying speeds, you end up with results like your video. i do have the model sat waiting for a spinner so i can go test fly the puppy. i have used a YS 63. i mounted the motor at a similar angle to what it gives for a 2 stroke and i only have rocker cover and the exhaust out of the cowel. i also moved the tank back as far as possible to get it nearer the CG as i thought it well forward and worried about cg changes during the flight. i hope the maiden ends up a little better than yours. i'm starting with a 120mm cg location.

Negative on the 'too much elevator' loco....the guy I had maiden it is mucho excellent pilot.
If you listen closely, you can even hear him say during the flight, "You've got serious outa balance goin here man". He knew right away it was balance problem. Luckily, he was able to set it down softly enough to not cause serious damage. I think I'm gonna take canopy2k's advice and rebalance starting at 100mm. Good luck on your maiden at 120mm,...I'm crossin my fingers for ya. Let us know how it turns out.

Hmm, the kyosho S-2c 40 CG has been mentioned in serval reviews long time ago already...

http://www.rcuniverse.com/magazine/a...article_id=219

"The recommended CG of the airplane is 130mm back from the leading edge of the top wing and I found mine balanced at about 115mm. Moving the battery back in the fuselage got it to around 120mm, which proved to be just fine for the test flights. With little elevator trim needed it seems to fly pretty level at this CG and is plenty responsive."


and also this one:
http://www.kyosho.com/reviews/kyoa1028-rcm.html

"and the model pancaked in, destroying the lower wing, ripping out the landing gear, cowl, muffler, and fracturing the upper wing in several places. It was indeed a humbling experience to call our editor the following Monday and explain what happened. Great Planes was kind enough to send a second model to review, and we proceeded to assemble it for the next attempt. This time we moved the Center of Gravity forward to 120mm."

I have been flying mine for two years and it is one of the best flying planes I have ever owned.Mine balanced out at the recommened balance point.Battery and receiver are about the leading edge of the bottom wing.I have a O.S..52 Surpass up front.The only bad habit is take off's on pavement and I put a gyro on the rudder and I can go the full length of a paved runway on the mains with no problem.If you fly off grass you probably don't need the gyro.Hope you get it worked out,it is a blast to fly and lands like a baby as long as you bleed off the airspeed on approach.

I moved the battery to the back, and got it balanced at about 105mm with no lead. Took it up today and put a few leisurely flights on it. I think Im going to put a rubber tail wheel on it. Wore the foam one down really bad just taxiing around. I think I may move the CG back a touch. It was just a little mushy. But definitely a good place to start. Perfect landings. It really landed very very easily. It can get away from you on takeoff though. Dont start chasing it. Shut it down and start over. Youre already way behind the curve!
Brice

With different "good cg location" results coming from different people with the same airplane, is it possible that it is a result of not taking into account the sweep of the top wing coupled with the particular cg machine being utilized?

I am using a great planes cg tool, and I noticed that, due to the width of the 2 measuring arms, that the measuring pins set back 10mm from the center point leading edge (farthest point forward) of the top wing. This means I have to add 10mm to whatever I set the rulers at the cg tool in order to get the measured cg point. According to the Kyosho diagram, it shows 130mm from the farthest point forward on the top wing.

It looks like I'll need about 3 ounces of tail weight to hit 125mm (I have a Saito 82 sitting up front). I certainly want to hit the right spot as the 1st flight will probably be next weekend. From the discussions so far, I think I will set it at 115mm from the center of the leading edge.

Good luck airbatx.....heres the maiden flight of mine balanced at the recomended CG point.

http://home.dc.rr.com/maurie/PittsMaiden.wmv

Successful 1st flight last evening! I'm going to have to tone down the rudder & elevator a bit though, as this is a squirrelly little plane with a monster rudder. I had the elevator throw programmed at 80% and it was still a bit much. The Saito 82 is as much engine as you could possibly want on this thing (12x7 prop). I really never surpassed 50% throttle on the whole flight, even during takeoff. It lands really nice at slow speed. From touch down to stop was only 25 feet. I set the cg at 115mm back from the forward point on the top wing.

This is only my 2nd plane (the 1st being a 60 scale Sportsman Aviation P-40), but I would rank this as harder to fly than the 1st. It keeps you on yer toes...for sure. What a blast!