Old Airtronics 94510 1/4 scale servos
 

I am restoring a 12-15 year old 1/3 scale Sopwith Pup. Phase One is to just get it airworthy and see how it flies before delving any deeper. I have replaced all the electronics except for the 1/4 scale Airtronics 94510 wing servos. I'm getting ready to start this thing up for the first time and test it all out. I've modified the ends to fit my Futaba receiver; but I'm wondering about the feasability of using these servos. Because they are buried in the wing and larger than a standard servo, but smaller than a Futaba 1/4 scale servo swapping them out will be a bit of work. Does anyone know if I can trust these servos when this old, what to look for if they are "wearing out". Thanks.

RE: Old Airtronics 94510 1/4 scale servos
 

Splais,
I have a couple of these servos just recently sent them into Airtronics and had them converted over to "Z" leads. I had mine in a Yellow Aircraft Cap10b on the rudder and another plane was a 28lb Robbe Cap20. Pretty stout planes for a servo that only puts out 110 in/oz of torgue. Here are the specs :

94510 HD Large Scale Ball Bearing servo

weight - 2.3 oz
Torque - 110 oz @ 4.8 VDC (for 6 volt add 20% = 132 in/oz @ 6Volts )
Transit - .33 for 60 degrees (thats really slow by comparison to say High Tech HS 705 - 60° speed: .26 sec @ 4.8v
- 60° speed: .20 sec @ 6.0v - Torque: 161.00 oz/in @ 4.8v - Torque: 201.00 oz/in @ 6.0v

Motor - Corless
Dead band - 4 micro seconds
Water Proof - Yes
Ball Bearing - Single Ball bearing on the output shaft
Comments - Injected moulded case (dont break one you will never find a replacement )
uses standard size arms.

I broke the mount tabs off one servo case and even Aitronics had no replacements, Ebay may be your best bet. These servos should be able to fly your Pup around the patch but I would refrain from trying to Roll the plane or loop it. I think you need to get some flights under your belt first to see how the plane reacts. I flew a 1/4 fleet biplane on two 94102 standard servos on the wings and two 94102 servos in the tail with one 94510 for the rudder. I could loop and roll and snap no problems. My Airtronics servos were pretty tough and could take a pounding and keep on flying. If you get flutter you will see the whole wing wiggle as the 94510 servo holds its position pretty well. If you have a gear problem you will hear it slip as I think the gear train is nylon and not metal. I know the output gear is nylon as I replaced mine because the bearing was running rough.

Hope all this helps

Good Luck

JDS

RE: Old Airtronics 94510 1/4 scale servos
 

Thanks, I finished setup today and could see that these servos were noticably slower than the Hitecs I normally use. I've been flying a really slow WWI bipe on the simulator and have found you can't roll one of these things without a lot of forward stick when inverted, They just won't roll fast enough I guess with standard throws.

RE: Old Airtronics 94510 1/4 scale servos
 

They will run a little faster if you bump up the voltage to 6 volts. On the rolls try full aileron and rudder with some elevator over the top it may help. What is the Pup powered with ? how much does it weigh ?

jds

RE: Old Airtronics 94510 1/4 scale servos
 

Jeesh, sorry for the grammer in last post - typing to fast I guess. It's powered with a G62. It's a 15 year old bird I'm restoring. I checked the CG today and it's spot on. I'll try and weigh her tomarrow; I've been curious anyway. I have pretty much decided I'm going to have to change out those servos. When I was trying for final setup today there was just way to much slop in the ailerons - something like 1/2". Going to probably demount everything and and see about installing a pair of Futaba 3305's I have.

RE: Old Airtronics 94510 1/4 scale servos
 

Splais,
Wise Choice Grass Hopper ! Those servos are too old, too far gone, no replacement parts. I was looking at replacement servos and the Multiplex digital is about the same size -
Multiplex Power
Digi Servo
Gearbox Metal
# of Ball Bearings 2
Torque 4.8/6.0v 85 / 106.2oz
Speed 4.8/6.0v 0.29 / 0.24 sec
Size 1.85"x1.85"x.91"
Weight 2.89 oz

But its a $100 dollar servo.

The Futaba S3305 is a little short
Volts Torque Speed
4.8V 98.8 oz-in. 0.25 sec/60°
6.0V 123.4 oz-in. 0.20 sec/60°
Dimensions Weight
1.6 x 0.8x 1.5 in. 1.6 oz.

but like you said you already have these on hand.

Hope all goes well

Happy Landings!

Johnny

RE: Old Airtronics 94510 1/4 scale servos
 

I weighed the plane this morning - 31 pounds RTF. My system is running on 6v so the 3305's should be ok, except for having to cut the covering and modify the servo box which are in the wing root with a pushrod and bellcrank setup operating the aileron.

Steve

RE: Old Airtronics 94510 1/4 scale servos
 

Steve,
Go for it !

Ugh I hate having to tear into something and re engineer it. But thats why they call it modeling and not work.

Good Luck Post some pics when you get a chance.

JDS