Rudder torque?

[Ian Inverarity]

Craig,

For the V twin boat I buit a system to run two 8411's for the rudder. It was a trick bit of gear so that the two servos would not fight each other (being digital they can fight each other with almost full power if the travel is not exactly the same) and also if one servo died I would get about half the rudder throw. Amazing rudder power, you could not hold it! But was a lot of work and money, and that wsa before digital jumbo's.

Now there is Multiplex and Hi-Tec jumbo digitals I would not do the same again. The Multiplex is an absolute brick (red too!), metal gears, massively strong servo arms.

Ian.

 

[EatMyShortsRacing]

Ian,

How much are those big servos, and how much did you pay for the 8411?

Craig

 

[Ian Inverarity]

Craig,

I would have to check, but I think the Multiplex was about $250. It lists as $133.91 in the US. I looked up some info, it has 354 oz-in holding torque! I think the Hi-Tec is much cheaper tho.

I didn't pay full price for the 8411's, one was second hand and the other two a friend got me some good prices!

Ian.

 

[Don Templeton]

Pond,

Mike P said he has used a Futaba S3102 in his 20's and liked them real well. The Hitec HC225MG with ball bearings and metal gears looks pretty good at 66.7oz at 6v for 29.95.

Sure glad you have a sense of humor. You made my day! ;D ;D ;D

Don

P.S. I know that CS 80 is a real nice servo. You might check the speed against the other ones.

 

[EatMyShortsRacing]

Ian...

I need torque AND speed AND durability!!! Remember how fast this boat is going to be so it would want to react VERY quickly or it will end up in the bank!!!

Craig

PS I have got onto a guy who makes NIMh battery packs to order cheap. I just got a AAA 650mah pack with JR Gold connector for my 21 for under AUS$20 delivered... worthwhile talking 5 cell packs to him???

EMS Racing

 

[Ian Inverarity]

Craig,

If you are willing to make the effort and pay the money the system using two 8411's is unbeatable! It is as fast as an 8411 with twice the torque! if you like I could probably sell you all the bits to do it as even if I run that boat again I will use the Multiplex. The 8411's have found their way into other boats! There is ball links, alloy servo arms, the coupling that bolts to the hull, the ruddel link. Man that was a lot of work!

That is good pricing! I use 900mah 5 cell NiCad packs in all my boats.

Ian.

 

[EatMyShortsRacing]

Ian,

I will call this guy tonight to see what NIMH 5 cell AA packs would be worth. I will probably need two myself for the twin 90 anyway..

oh and do the 8411s handle 5 cell packs? I have some JR servos that state not to use 5 cell nicads (cant remember which ones... may be mini servos from my 21s)

EMS Racing

 

[Ian Inverarity]

Craig,

I have only used my 8411's with 5 cells, never had a problem. They can cope with 6 volts.

Ian.

 

[TimD]

I bought a 5 cell Sanyo 1400mAH pack with gold plated pins on a JR connector from Master instruments for $35.00 about 3 months ago. They work with 1/4 scale servos very very well. No need to re-charge them on a 2 day meeting! They last for ages!

 

[EatMyShortsRacing]

Tim,

My 250mah pack used to last me a 2 day race in my old 21 rigger..



EMS Racing

 

[damien_au]

Try a GWS (Grand Wing Servos) the s666nf 1/4 scale with metal gears on 4.8 volts 0.19 sec/60deg 18.5kg-cm/254oz-in

6.0volts 0.16 sec/60deg 22.5kg-cm/309 oz-in

Comes in blue or blue with nice rubber seal.

You can get them in Australia for about $77.oo AUD$

Try www.gws.com.tw/english/english.htm

 

[PondSkimmer]

Tom and Don,

Thanks for that info i think that i will be going with the Hitec 225 for the rudder on this 21.

 

[MikeP]

PondSkimmer,

The 225 Hitec has the same torque that I used on my .21 they are close to the min. torque needed. I set up my linkage to get the most mechanical torque (short servo arm and long rudder arm). You can also loose some torque if the radio box seals are to tight. The CG and turn fin placement have an effect on the effort needed to turn the boat as well. Good luck with your project, keep us updated on it's progress.

-MikeP

 

[PondSkimmer]

What do you guys think of a HS-605BB?

here are the specs:

http://www.hobbypeople.net/gallery/759394.asp

They seem to be fairly cheap and have 77oz/in of torque!

 

[Don Templeton]

If weight is not an issue, any servo with that kind of torque will be fine.

We were trying to give you light weight options! 8)

 

[_laxmasta2039]

PondSkimmer,

i noticed the great price/torque ratio on the 605 too and i was planning on getting one for the steering servo on my Pheonix.....Don, is the 605 larger than a standard [non 1/4 scale] servo? i saw in the new RCBM buyer's guide that Hitec has a servo that is basically the same as the 605 but "without the extra bulk"

Joe

 

[Ian Inverarity]

I have had a few bad experiences with the mini type servos. Even tho they may be rated at enough torque they often aren't built as tough as standard sevos, so if you take a hit on the rudder you can damage them. The weight saving is pretty minor when you compare it to the weight of even a 21 rigger.

Ian.

 

[TimD]

Best standard sized servo I've ever used is the hitec HS615MG. I think they are discontinued now. Awesome for rudders in outboards.

I'm using one in my 21 rigger for the rudder - nothing like a bit of overkill!

 

[PondSkimmer]

I see that there are some on ebay: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewI...&category=19164

But what is the speed, and size? They are not listed on hitec's site since they are in fact discontinued...

 

[Ian Inverarity]

Tim,

I had a couple of 605's, but they may not have been metal gear versions. I think the 605's were the high power, the 615 the high torque? Many years ago now. Killed them both in a few months, one died when I flipped the old MRP Mach1 tunnel, the other died in my 21 Stinger hyrdo. Put me off Hi Tec for life! :

That said a lot of people are using them now, so they must be better than when I tried them... ;D

Ian.