SAW LYNX Tunnel Build - Carbon Fiber Box

[DPeterson]

Hi Joe

Nice job as usual. Will you be at Arizona this year?

I am doing a Woodstuff Tunnel where I to am looking to do the rear exposed steering servo. How water proof is the servo where the spline exits the case? Is a certain brand better than others for water proofing? Being that I flip peridiocally I am nervous about this exposure.

Later - Doug

 

[HOTWATER]

Doug, check out the Traxxas dh-2075...I have not used one before but they are supposed to be water resistant

offshoreelectrics has them...

-Kent

 

[TinoAlmanza]

Being that I flip peridiocally I am nervous about this exposure.

Later - Doug

Periodically? I pitted for you 8 times and we never saw turn 3?!!

Sorry, couldn't help it. :blink:

 

[DPeterson]

Tino

Now you know why I changed my pit guy!

Kent

I will check out that servo. Hate to give up using my futaba's.

Doug

 

[Jim Caldwell]

Doug, I put a smear of teflon grease around the splines before I put the steering arm on then wipe off the excess. No problems in 8 years, but I also seal the wires and case joints with a light smear of Goop also.

 

[Darin Jordan]

HiTec now makes a waterproof servo as well.

http://www.hitecrcd.com/products/digital/waterproof-servos/hs-5646wp.html

I'm guessing it's better quality than the Traxxas...

 

[JSCARPINO]

Doug, I put a smear of teflon grease around the splines before I put the steering arm on then wipe off the excess. No problems in 8 years, but I also seal the wires and case joints with a light smear of Goop also.

I just used a Nitryl O-Ring with some Grim Racer cable grease.....

Has not leaked yet with a full season of racing.

Thanks

Joe

 

[D. Newland]

I just bought one of those Hitec waterproof digital servos. Haven't used it yet, but the price seemed pretty good. $55 or so at Servo City. It's just slightly larger than the MG 645. And I mean slightly, but I had to make a new mount.

 

[DPeterson]

Thanks for posting the picture of the o-ring idea Joe. Seals the deal for me as I now know how I want to proceed with one of my builds.

Darrin and Dave - The Hitec sevo shown is rated around 160-170 oz/torque. Due to handling problems back here in Wi. most of us went to 300 - 350 oz/torque servos. Handling issues went away. I am surprised and confused how a 160-170 oz/torque servo can work.

Doug

 

[D. Newland]

I've been using (and still use) an MG 645 in my OPC...and that's even weaker than the one I posted.

 

[DPeterson]

Interesting Dave, I used to run all 645MG's. Started to tear them up in my heavier P-Mono and P-Offshore rigs. With my tunnels I started with a lower end 1/4 scale servo as was recomended by a nitro tunnel guy and tore that up eventually.

Now I run Futaba Digital S9156's in everything. 340 oz/torque. Overkill for most set ups but I have eliminated all issues related to too soft of a servo. Now if I could find a cure-all for other areas of weaknesses. Thanks to Mike Z. for the S9156 recomendation.

Later - Doug

 

[jeepers]

I also had some handling issues with mine and my dads tunnels, we were using 645MG's for steering, I switched both servos on the tunnels to Hitec HS -7955 TG 330oz/torque, Handling issues went away after changing to the stronger servos.

My LSH uses a Savox SC1268 MG High voltage servo 360oz/torque at 7.4v. I agree with Doug, the stronger servos in my boats eliminated lots of issues.

Sean

 

[D. Newland]

My post above is missing some info that I thought I typed in there...? No big deal, but that Hitec waterproof servo is slotted for my Q mono.

Anyway, what Rx voltage are you guys running in your OPC's? I've been using the Castle BEC voltage regulator set at 6.5 volts with the MG 645 and seem to get good response from it...but now you guys have me thinking.

It will be good to run them next month! Heck, my P mono had run an MG 225 for years and now I just stepped up to the digital equivelent 5245.

 

[DPeterson]

I am betting you can make the lower oz/torque work because you are such a good driver. I lost some of my 645MG's after some terriffic crash's. I did notice a significant handling difference in my 11 pound 60 mph P-Mono when I put in the stronger servo.

With the Outboards the servo is operating against the thrust of the prop. Last year at London, ON. Mike Ball had major handling issues with his tunnel. He borrowed my S9156 and couldn't believe the difference it made.

I'm still running 5 cell (6v) nimh's.

You know - the last thing we all need to do is help you win your races.

Doug

 

[D. Newland]

Ha! My next OPC build (hopefully before the Nat's) will have the servo mounted on one side of the radio box, and a longer arm with 1 beefy pushrod going to the outdrive.

sorry for the hijack, Joe!

 

[jeepers]

My tunnel would handle fine as long as I kept the props in the 38-40mm range using the 645MG. when I started propping up to 42-45mm prop size's I could go in to a turn smoothly but it did not want to straighten up I would end almost going full left to try and straighten it out.

I am also running 6v nimh expect for my LSH, I use a lipo because it has a high voltage servo.

 

[jeepers]

Ha! My next OPC build (hopefully before the Nat's) will have the servo mounted on one side of the radio box, and a longer arm with 1 beefy pushrod going to the outdrive.

sorry for the hijack, Joe!

how beefy are you thinking???

I have seen one tunnel that used a single arm but the used a beefy turnbuckle from a RC car