Steve biplane Posted May 22, 2008 Share Posted May 22, 2008 After about 5 hours air time my Travel Air developed a 'funny noise' . On investigation this appears to be because the Futaba S148 rudder servo has worn bearings (and possibly output gears).; it was new servo when fitted. The result is that the rudder has a small amount of play around the neutral position. It looks like the elevator servo, also an S148, is developing the same problem. Can anyone suggest a more robust servo of the same size? Do I need ball bearing supported output shaft? And suggestions that are not going to break the bank would be especially welcome!Regards,Steve Quote Link to comment Share on other sites More sharing options...
David Ashby - Moderator Posted May 23, 2008 Share Posted May 23, 2008 Strange Steve, the good old 148's should be ok with a model of that size - assume you've got a normal .40'ish sized motor at the front? I use Futaba 3010's for tougher applications 6kg torque but they're £19.99 admittedly Quote Link to comment Share on other sites More sharing options...
Steve biplane Posted May 23, 2008 Author Share Posted May 23, 2008 David,Thanks for your reply. My Travel Air has an LA46 up front so I don't think it's overpowered. In fact it seems like a nice match and has achieved what I wanted which was to start learning some aerobatics. Steve Quote Link to comment Share on other sites More sharing options...
David Ashby - Moderator Posted May 23, 2008 Share Posted May 23, 2008 Sounds good, I was asking just in case you had popped a bigger than normal motor in the front. Thinking about it, I'd probably be tempted just to replace like with like and put some more 148's in. Perhaps the ones you have came from a bad batch? Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted May 23, 2008 Share Posted May 23, 2008 I shouldnt think a SMALL amount of play in these servos is anything too worry about too much, especially on a simple machine like the travel air - after all precision aerobatics are not on the schedule. Of course, if the slop is so bad that control may be compromised, or safety of the installation etc, then change them. Mnay people swear by a ballraced output shaft, where loads are heavy, and there are some nice karbonite geared servos around presently too. Quote Link to comment Share on other sites More sharing options...
David Ashby - Moderator Posted May 23, 2008 Share Posted May 23, 2008 Just thinking again and Steve you'll forgive me if this sounds a bit basic (fill in your profile btw ) but is it a case of a little slop on the linkages? Or are the servo output arms moving when the control surfaces are lightly touched? Quote Link to comment Share on other sites More sharing options...
Former Member Posted May 23, 2008 Share Posted May 23, 2008 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
David Ashby - Moderator Posted May 23, 2008 Share Posted May 23, 2008 Yes you resist mate Quote Link to comment Share on other sites More sharing options...
YakMad Posted May 23, 2008 Share Posted May 23, 2008 148's have no bearing in case the output shaft bearing is just the case and the case wears, I only use them for throttle, I have switched to Hitec if I want a cheap standard servo. If you rock the servo arm itself there should only be slight play on a 148 servo, any more and the case is worn, it can be replaced but it's not worth it. Quote Link to comment Share on other sites More sharing options...
Former Member Posted May 23, 2008 Share Posted May 23, 2008 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Steve biplane Posted May 23, 2008 Author Share Posted May 23, 2008 Thanks for the replies guys. It is like YakMad says, I can rock the rudder servo arm noticably more than, lets say, the throttle servo arm. Control of the aircraft is ok (or more likely I'm not good enough to notice the difference!) and I wouldn't do anything about it except that I can hear something buzzing on the aircraft during a slow pass and, being the cautious type, I'd prefer to fix the problem before something lets go. The first thing I did was check the hinges on all the control surfaces, all ok. On ground running I've noticed that the rudder can vibrate when the engine is run at somewhere around 1/3 throttle and it produces a similar noise. If I hold the rudder servo arm there doesn't seem to be any slop in the linkage back to the rudder so I think it's a servo problem. Anyway, a new servo is going in so I hope the problem will go away. I will also treble check the linkages for slop at the same time. YakMad, do know the number of the Hitec standard servo to which you refer? I assume Hitec servos are compatible with Futaba radio gear? Thanks again,Steve Quote Link to comment Share on other sites More sharing options...
winchweight Posted May 23, 2008 Share Posted May 23, 2008 You've just been unlucky. My Super Air (OS46LA powered) and many others have 148's in and they're all fine. Luck of the draw, I suppose. Quote Link to comment Share on other sites More sharing options...
YakMad Posted May 23, 2008 Share Posted May 23, 2008 Steve, Try Hitec HS-322 or HS-325, the HS-325 would be the better option as it has a stronger gear train, if you shop around there is always deals going on these servos, all modern servos will be compatible with Futaba radio gear, so long as you are not using some of their high end 2.4 ghz receivers, but that another story......... don't forget you can always use your 148's on your throttle as apart from the slop they are a fairly reliable servo. Quote Link to comment Share on other sites More sharing options...
Steve biplane Posted May 23, 2008 Author Share Posted May 23, 2008 Thanks for your help everyone. A new servo went in tonight and the set-up seems much better. The new servo was another S148 that I had spare and I will monitor how it lasts. I will be investing in some HS-325's when I attend one of the big shows in the near future. Thanks again for your advice, Steve (who is hoping the weather forecasters have got it completely wrong for the bank holiday!). Quote Link to comment Share on other sites More sharing options...
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