Wondering about changing out my servos..

[Beemerider]

I'm in the midst of rebuilding/repairing my old Explorer 2M motorized sailplane. It has two Futaba S148 servos from my very first radio of 20 yrs ago. They work fine and really never saw much use till this year when I really learned how to fly. I have a few more of the same which are still 20 yrs old but have never been used. And a couple more made by Tower Hobby. I also ave a handful of the little 9gram servos from the various folks. I'm wondering if I'd be smart to change them out of the sailplane at least with the same or go for the 9 gram for more weight savings? Or is this too much plane for the 9g?

[CHELLIE]

Originally Posted by Beemerider

I'm in the midst of rebuilding/repairing my old Explorer 2M motorized sailplane. It has two Futaba S148 servos from my very first radio of 20 yrs ago. They work fine and really never saw much use till this year when I really learned how to fly. I have a few more of the same which are still 20 yrs old but have never been used. And a couple more made by Tower Hobby. I also ave a handful of the little 9gram servos from the various folks. I'm wondering if I'd be smart to change them out of the sailplane at least with the same or go for the 9 gram for more weight savings? Or is this too much plane for the 9g?

Hi if the Original Futaba servos are working ok, use them as long as they are not binding or sticking, you can use the 9 gram servos too for a 2meter sail plane if you like, they will work fine, here is my 48" foam profile plane with HXT 9 gram servos and a 480 Motor.

http://www.wattflyer.com/forums/show...katana+chellie

Scratch Built Katana Profile 9mm Foamie

[kyleservicetech]

Originally Posted by Beemerider

I'm in the midst of rebuilding/repairing my old Explorer 2M motorized sailplane. It has two Futaba S148 servos from my very first radio of 20 yrs ago. They work fine and really never saw much use till this year when I really learned how to fly. I have a few more of the same which are still 20 yrs old but have never been used. And a couple more made by Tower Hobby. I also ave a handful of the little 9gram servos from the various folks. I'm wondering if I'd be smart to change them out of the sailplane at least with the same or go for the 9 gram for more weight savings? Or is this too much plane for the 9g?

You do have to worry about the servo's feed back potentiometers. On servos that old, they might not be using the hard carbon pots currently used. Those pots can get electrically noisy, causing jittery operation of the servo.

So, operate those servos very slowly back and forth a dozen times or so, both with load applied with your fingers, and with no load. IMHO, any "Jittering" during the slow operation is cause for replacing them. I just had a expensive Futaba high torque digital servo only a year old do that. It got replaced.

(If you go many years back to when volume controls on AM-FM radios got real noisy, that is the same type of failure.)

[Rodneh]

Those old 148 servos are probably the most reliable low priced servos ever made. The only ones I ever wore out (the pot wipers actually had worn a path through the conductive coating on the pot) but only after about 3 years of almost constant flying, at least a 1000 flights. I have many more of them that are still in use.

[Beemerider]

Thank you to all!

These two in the sailplane most likely have under 25 flights this year and probably less than 5 from 20 yrs ago. (The first plane lives a tough life!) It's been on the shelf since July I think. It's well on it's way to a new life though. I'll post a couple of pics when I'm done with the rebuild. Lord knows I'm slow--hope that translates out to a good job!

Kyle--I didn't know how to check the servo like you described. Makes perfect sense to me as I've worked on dozens of radios through the years and have a couple of cans of tuner cleaner around I would occasionally use on a noisy pot.

These servos are near 3 times the weight of the 9 gram so I may still consider changing them out. Not sure--guess it's a gamble--older might be better or maybe not. (at least when it comes to us older folks: older is always better!)

[solentlife]

I still have what were excellent servos in their day ... JR NES 1001 ... NES 5001 ... NES 301 .... all worked fine.

I fitted then to my big Biplane - Skymaster with 15cc Gas engine. They'd previously in the 80's been installed in my earlier Skymaster.

4 flights later - elevator servo failed. Checking after seemed servo was fine - but cont'd checking and loading up showed it to fail.

Those servos are now shelf ornaments.

Nigel

[kyleservicetech]

Originally Posted by solentlife

I still have what were excellent servos in their day ... JR NES 1001 ... NES 5001 ... NES 301 .... all worked fine.

I fitted then to my big Biplane - Skymaster with 15cc Gas engine. They'd previously in the 80's been installed in my earlier Skymaster.

4 flights later - elevator servo failed. Checking after seemed servo was fine - but cont'd checking and loading up showed it to fail.

Those servos are now shelf ornaments.

Nigel

Ouch, that hurts. My new Hanger 9 Kantana model uses two one year old servos for the ailerons, and two servos for the elevator. Some sort of backup protection I guess.

[solentlife]

Originally Posted by kyleservicetech

Ouch, that hurts. My new Hanger 9 Kantana model uses two one year old servos for the ailerons, and two servos for the elevator. Some sort of backup protection I guess.

It's a painful memory ... I inverted her and completed a downwind turn at moderate height ... commenced a descent line into a low inverted pass along runway ... just as she leveled out - she nosed into a vertical dive into the tarmac ...

Video is on my channel " solentlifeuk " .....

Initially as heard on the video - I think I've given UP instead of DOWN command ... a common mistake. But study of the video shows the model makes NO deviation from that dive despite my giving elevator commands.

Nigel

[kyleservicetech]

Originally Posted by solentlife

It's a painful memory ... I inverted her and completed a downwind turn at moderate height ... commenced a descent line into a low inverted pass along runway ... just as she leveled out - she nosed into a vertical dive into the tarmac ...

Video is on my channel " solentlifeuk " .....

Initially as heard on the video - I think I've given UP instead of DOWN command ... a common mistake. But study of the video shows the model makes NO deviation from that dive despite my giving elevator commands.

Nigel

Worst crash I ever saw was years ago when a club member was flying his very fast model over the field inverted at about 10 feet high. Another model went to fast and its wing exploded with a very loud bang.

The inverted guy hit full up elevator. Two real bad spats in 5 seconds.

[CNY_Dave]

Heh, toughest thing to remember is the stick doesn't control up/down, it controls towards the cockpit/towards the gear.

[solentlife]

Originally Posted by kyleservicetech

Worst crash I ever saw was years ago when a club member was flying his very fast model over the field inverted at about 10 feet high. Another model went to fast and its wing exploded with a very loud bang.

The inverted guy hit full up elevator. Two real bad spats in 5 seconds.

At a public fly-meet in UK I was part of ....

I was flying my RM Racer pylon racer and Tony B decided to put his Curare Aerobatic machine in the air ...

I'm doing what a pylon job is best at - displaying high speed knife edge turns into flat out passes .... Tony decides to do similar - BHAM ! I sliced of his wing when he turned across in front of the RM racer ... nothing I could do about it.
Both came down ... his was a total wreck .... my RM Racer needed the L/E repaired and was in the air next meeting.

Nigel

[dgjessing]

Originally Posted by CNY_Dave

Heh, toughest thing to remember is the stick doesn't control up/down, it controls towards the cockpit/towards the gear.

Great advice - I'm going to *try* to remember that

[Beemerider]

So that's what those sticks are for. Now I know why all my planes are hitting the ground.

[CNY_Dave]

Just remember, if you move the sticks the wrong way it 'was the radio'.