View Full Version : need some opinions -re rudder setup - new Extra 300L
09-12-2004, 06:22 PM
I just purchsed a second hand Ohio RC Extra 300L from WildBill at the London IMAC. I am currently flying the same airframe that I bought two years ago from Randy Brown, and I like it a lot.
Here is the thing: The one I got from Bill was just the airframe (I am putting in my own engine, and electronics). Everything is straight forward, and I was planning on doing the setup the same way as on my current Extra, which has a large (Hitec gant scale digital) servo for the rudder with a pull-pull setup.
The airframe however was set up for a single rudder servo mounted in the tail.
My options are to redo the rudder, for pull pull with a 250 ounce servo mounted in the fuse center section like I have in my other one (more work but I would feel "better"), or I can put a 180 ounce (Hitec 5945 digital on 6v) servo back in the rear end and use a single stiff pushrod (easier)
What do you guys think? If it matters, the plane is about 21 lbs, and the rudder is not oversize, ie, not for 3D just for IMAC style aerobatics. But I plan to fly the plane pretty hard :)
Check your balance with everything in place.
Make your decision based on where you need the weight.
09-12-2004, 08:30 PM
When i had the zenoah in the front it balance perfect with the battery's just aft of the wing tube. i don't know how heavy the Brison is in comparison, but i think it would be close.
09-12-2004, 08:36 PM
I am using two 1100mah nicads for the receiver, mounted behind the wing tube as you did, and one 1700 mah for the ignition. I think my 4.2 will be a little heavier, its 5.5 lbs with the muffler (but no ignition or battery)
I was just wondering mainly if the single rod/rear mounted servo is OK, or should I go to the trouble of installing a pull pull system? I wasnt too worried about balance as I can move things to suit.
09-12-2004, 08:43 PM
I had no problems, it woul dclimb knife edge with just the 945, use 4-40 hardware and you should be allright.
09-12-2004, 09:17 PM
The more torque you can get to the rudder the better in my opinion that's why I have pull pull and ganged servos. :wink:
09-12-2004, 10:05 PM
Andrew, I have both systems set-up on my planes, and the pull-pull wire system is by far the smoothest.
If you can go with pull-pull go for it. If your plane is going to require major weight in the tail, then use two servos on the rudder in the tail (one on each side) in a push-push system. This is what I am using on my Hangar 9 CAP 33% since I am using a Zenoah 80 in the nose.
A single servo in the tail on a plane that big might not be the best solution.
Needless to say, 4x40 rods for sure are needed with ball links for an even smoother movement.
09-13-2004, 06:26 AM
Thanks guys for the replies.. I think I will go for the pull pull and giant scale servo.
Bill, I dont doubt that the single high power servo in the tail would work, but you gotta' know me, I am a sucker for overkill when it comes to servos.. :)
09-13-2004, 03:32 PM
I understand Andrew, i would have done the same probably but it was set-up that way when i got it and wanted to get it in the air asap. I hope it works well for you,
09-13-2004, 03:42 PM
Also if I am right..KP had his servo under his canopy also with a 4.2 brison upfront
09-17-2004, 09:51 PM
Been working on the plane the past few nights. I made a long drill bit from a piece of brass tube (with serated end) glued onto a 36" piece of music wire. Drilled the holes through the bulkheads for the pull pull wires, worked great!
I have allmost all the gear installed into the plane, and hope to test fly next weekend...
09-18-2004, 07:22 PM
Spent all day today finishing up the Extra....
Took 15 hours to get it RTF, not too bad.
Its all set to go, with the new servos (Hitec digitals) and battery packs, switches, linkages etc. Cleaned up the covering and went over all the hinges, etc. Looks sweet!
I matched the control throws to my existing plane, and I tried to match the down and right thrust as well.
It balanced in the same place as my other Ohio 300L without adding any weight, but the funny thing is that this plane is 10 ounces lighter! The one I got from Randy two years ago weighs in at 20.68 pounds with the ZDZ 60 and this one I just bought weighs 20.02 lbs with the Brison 4.2. All servos, battery packs, etc are the exact same and in the same place. The ZDZ version did need some nose weight to balance properly though.
Anyhow, its nice to have two of them now for IMAC. :)
09-18-2004, 07:50 PM
Andrew, have you ever had a problem with your hitecs locking up like i readabout on rcu? Also any pics? :)
09-18-2004, 07:59 PM
Chris, I have been flying the Hitec digital servos since 2001 when they became available from Great Hobbies. I have flown about a dozen 5945's mainly but also some (6 I beleive) 5645's, and 5 of the giant scale (5735) ones. I have never had any problems at all with them. I am currently using them in both my turbine jets, both these Extra'a and I had them in two other giant scale models of my own design. I trust them, and will continue to do so in the future. I dont beleive everything I read and especially regarding the Hitec servos. Some guys on RCU are out to trash them even if they never owned any... you know my policy on talking about stuff you dont have actual experience with!
No pics yet, will do when I get out to the field to test fly. I am interested to see how the 4.2 hauls the plans VS the ZDZ 60. I am currently running a Mejzlik 24x10 on the ZDZ 60, and a Bolly 24x10 carbon on the Brison 4.2
09-18-2004, 08:26 PM
yeah and i wasn;t putting them down, as I do have the 5645's picked for for a 3d plane that I have. but i was just curious. I also do not believe everything i read just liek to get some more opinions on what i read
09-18-2004, 08:58 PM
The 5645's are pretty darn good servos. I hve them on my ailerons of my red Ohio Extra, and also in my AV8R jet. But, the 5945's are a lot better. Faster, a lot more powerfull and coreless motor centers better. The prices have come down in the past year...
I know you werent putting them down. I can only offer my experience though. I have had allmost every brand of servo fail on me at one time( jr, airtronics, futaba, etc), and I still trust them all. :)
09-19-2004, 07:32 AM
Andrew......I have just finished the initial test flights successfully on my 30% Staudacher ( 90"/<20#/ZDZ 60 Bisson wraparound).
As you know I have been flying taildragger gassers for several years now all with pull pull and its the best way to go IMO.
The set up I like best is a single servo placed to suit the ballast needs for CG location,driving a central tiller bar with the pull pull cables to the rudder.The parts are standard SIG for the tiller bar as used in the 1/3 Spacewalker.
The Staudacher has a slight tail heavy problem and I have been flying it with lead ballast taking some out each flight .
It now looks like the CG will be fine with no ballast once the cowl is on and the rudder servo will be amidships with the tiller bar set up.
You have got to be kidding about those 250oz servos :shock:
09-19-2004, 08:19 PM
You have got to be kidding about those 250oz servos :shock:
Probably not. :D
I'm using one of them (5735) in a pull pull configuration on my 35% Cap 232. Works great for me. (I'm not a "3D'er", although I occasionally try some of those maneouvers.)
However, the 5735 has been discontinued. It has been replaced by the 5745. It is rated at 250 in./oz. of torque at 6.0v. The 5735 was rated at 264 in./oz. of torque at 6.0v.
09-19-2004, 08:41 PM
The 5735 certainly is strong, and yet it is very fast as well. The first time I was playign with one (three summers ago) it had the long servo arm on it, and I pinched my finger against the servo case, was so stunned I forgot to just release the transmitter stick for a few seconds! I thought I broke my finger... :)
I allways like to err on the too strong side of servos rather than the too weak. I am 100% certian in the extra, with 180 ounce/ inches on each aileron, and each elevator half, and the 260 on the rudder, I will be OK, heh heh :)
Arent modern servos great! :)
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