japan3d

Just finished building it, and went to balance model and discovered it will require almost 1 1/2 lbs of lead on the firewall to balance her. Gt-80 engine, all equipment installed per manual. What wrong here? Anybody else have this problem

tp777fo

My Feedback: (28)

Hi Japan3D,

I have a new Su-31 with GT-80. I used 20oz. lead to get mine to balance. Battery pack is all the way forward against firewall. It balances right on the correct spot. This thing flies great! Does everything I want it to do. Takeoff's are dead straight with little right rudder, landings are at a crawl. It flies like a trainer on steroids! You have done nothing wrong, just balance it correctly and you will love it.

Tom Perry
Schertz, TX, USA

japan3d

Thanks TP777fo,
I guess the extra weight does not bother this combination. Will install the 18 oz tomorrow. Have to wait till next weekend to try it out. I now own all 3 1/3 scale ARFs from Hangar 9 The CAP 232 required weight in the tail about 7 oz, and the Extra 330l balanced perfectly with no weight, All 3 use the GT-80 for power. Where does yours balance? Forward or Aft of the center of the tube or right in the center?
Once again Thanks

Richard Bombash
Tokyo Japan

tp777fo

My Feedback: (28)

Right in the center of the wing tube. Sounds like you have quite a collection. I think you will enjoy flying the Su-31. Let me know how it goes.

Regards,

Tom Perry

Geistware

My Feedback: (16)

japan3d,
Where outside of Tokyo do you fly?
I come to Kagagawa once a year.
I would like to see

japan3d

I fly at a US military base named Sagami Depot, in Sagamihara City. I'm the only one who flys there. The other guy left in june.

karl hibbs

My Feedback: (6)

the su-31 is a good flyer,but i have found that the su flys better with the cg back 1.25" from the center of the tube. i have 30 flights on it as of 8-27-02. i am using the zdz 80 single, it is a good power combo, even for 3d. the zdz is just now coming to life after 5 gal of gas. i moved the cg back a little at a time, the last 20 flights have been at 1.25", it could go back more. don't be afraid of it, it is a big yellow trainer...

jpeters

What length servo arms are you using on the ailerons. I have hitec digital 5625 and was going to use the stock al. arm 1" but they seem to short and the control rod won't line up with the hard block in the ailerons it hits at the very edge. Do i just instal it at the edge or angle the push rod so it hits more center on the block? I dont think either are a god idea. but i can not find longer arm for the hitec. Also what about the elevators it calls for 1' arms also do i use the standard hitec 1" or go longer

japan3d

Hi Karl,

Haven't flown mine yet, hopefully this weekend if the weather agrees. How much lead did you have to put on the nose to balance? How much have you've taken out to get the CG where its at now?

jpeters
I used the H9 arms that came with the hardware kit. Just run a little thin CA in the holes before tap them.

japan3d

jpeters

the H9 ones are for Jr or Futaba I dont think they make ones for hitec.

David DeWitt

My Feedback: (289)

Dubro makes a composite control arm for the Hitec servo's,they are made for giant scale aircraft. The package comes with several different size arms. The longest arm 1 1/4 " seem to work fine for aileron,elevator and rudder servo's. (the outside aileron servo needs the shorter 1" arm to avoid binding at full throw) The package of arms cost less than $10.00

Aero-X

I heard that TNT may have metal arms for the Hitec's. Nothing on thier web site but you may want to give them a call.

Mrt1750

My Feedback: (1)

I had a hard time finding alum. servo arms the first time, I found them at chief aircraft.com. They are also available from Creek Hobbies, in Mt. Laurel, New Jersey. Creek hobbies can also be found in almost all magazines, with large adds.
These are for 3D use 1/2 arms are 11/2 in. long hope this solves your problem.
I'm interested in this Plane but wanted to use a ZDZ-80 single it only weights 4.2 lbs.,have read so much about balance that I now have reservations and don't think I want to have to add 1, or 11/2 lbs. of lead in the nose. Could you have moved the motor farther forward by the use of engine stand-offs to change the CG

Thanks
Mike

Forgues Research

My Feedback: (7)

Now if you really want performance with your 3 planes, stick a ZDZ 80 single in them..

jpeters

5 of us purchased this plane and 4 out of 5 pilots recommend using the zdz single 80 . We went with 2" al. stand offs, pull pull forward of the wing tube, carbon fiber wing tube and tail gear. 6 volt 2700 pack for reciever and 1650 for ignition both nmih. batteries will be mounted on fire wall. If more weight is needed i am building out the fire wall the distance of the stand offs and then i will mount the batteries up there. With all that i dont think much if any weight will be needed.

Geistware

My Feedback: (16)

The only thing I can find is Camp Zama.
I can't find a map so I don't know where this is with respect to Narita Airport.

japan3d

Sagami Depot is about a 20 minute car ride from Camp Zama. Have you've heard of a road that is called Chicken Farm Road? Route 507. Its on the end of that route. Its a good 2 1/2 - 3 hour ride from Narita, and thats on a good day. Throw in a accident and double or triple that time.

http://map.yahoo.co.jp/pl?la=0&sc=5&...&MD.x=8&MD.y=9

sagami depot is right by the arrow in the middle left of this map

bpryor

My Feedback: (45)

My favorite Hitec servo arms are from Air Wild: http://www.airwildhobbies.com/ . They're excellent quality and come in either "+" or non "+" sizes for perfect fit. If you're not aware, there are two different sizes of shafts on the Hitec digital servos. If you look at the top of the output shaft with the servo arm off, there will be a "+" on top of the shaft....or not. Make sure and get the correct ones for your servos.

jpeters

bpryor

I just recieved my servo arms from airwild hitec digital with the +.
my question is they are extreemly tight is this normal. the package had the number that was for non + and they hand wrote the number 2 over the 01. called airwild they said the red is for the + and i got the red ones, However you need to force these on.

bpryor

My Feedback: (45)

Hi jpeters,

They should fit tightly. What you don't want is a loose fit. If you can get them on without using a hammer( ), they should be fine. It sounds like they are the right ones.

jpeters

bpryor

You can force them on but you have to take them out of the plane so you can put a little a** behind it! definately no slope here!

karl hibbs

My Feedback: (6)

japan3d, i did not use any lead . i moved the rudder servos to the just behind the wing tube and used pull pull. i put the batterys on engine box. it was 1/2" aft cg, i flew it that way 2 flights and did not like it . so i put the servos in the tail and tried it agin. then i moved the rx battery back to the wing tube. now i am at 1.25" behind center of tube. i will try the cg at 1.5" and let you know how it is. Karl

japan3d

When I went to balance it on the center of the wing tube I just ran string around the tube then ran a dowel thru these. On the other H9 1/3 scales they give a dimension for the CG at the wing tip. How do you balance yours? Do you have some sort of set up or know where on the wing tip the CG is for what you are using.

It seems to me that Horizon is very conservative on the CG for this plane.

karl hibbs

My Feedback: (6)

japan3d, i used the great planes cg stand ,and i think it was 7.125" from the leading edge at the root . if you use this stand be sure to spread out the load with 3"x3" 1/8" ply as the balsa is a little soft. my su is 25#. Karl

hmorin

Karl, what do you have for an engine? Do you fly at RAMS field? I am a good friend of Lloyd's and he has mentioned your name a few times.

Howard