32" Imex Cat

[tiqueman]

I ordered that rudder from OSE, so in 5 to 7 buis days, we shall see what happens.

[Simon.O.]

Rudder depth
As a rule of thumb I use the diameter of the prop below the bottom of the prop when it is 12-6 o'clocck.
On a few of my hulls I get away with less but they are straight-line setups.

A long rudder will not cause as much drama as a too short rudder. Jay mentioned the extra drag of a rudder. He is right, there is f-all extra drag for a longer blade, especially when they are offset out of the propwash.

Any rudder in the propwash is going to create a lot of drag to begin with and then not be very effective unless it is very deep below the prop bottom line.

Go for the off-set and all will be better.

[tiqueman]

I think that after you get this all set and running good, you'll be buying a Feigao 9XL, An X442 prop and a good 120 to 150 amp ESC to make it run on 4s1p.

Subtle hints there....

Are you hinting that Im gunna blow some .... stuff up?

Well, at least I already have the prop!

So, 4s1p, thats 14.8v, so its what I ran last, using my (2) 2s batts in series, correct? BUT, 4s1p is one (1) battery pack, isnt it, (containing 4 cells) not 2 seperate batts? Lipo lingo sux. I think I may try it on a R2D2 4G 1P.. over.

Simon, and domwilson, if I use the rudder offset, does that limit me 100% to right turn only. I ask this for 2 reasons. 90% of the time I am only turning right, lets just face, the boat naturally turns better that way. BUT, often times I follow the bank around my pond depending if theres any duckweed floating so I may run like a "L" configuration. I doubt if I will be competitive racing with this boat. Maybe, but Im not sure yet.

So does an offset limit me from "sport boating"?

[domwilson]

I was hinting at upgrades. 2 X 2s1p in series is basically the same a 4s1p.

The offset rudder should be fine for your application.

[tiqueman]

Oh believe me, when I have the cash flow again, its on. For now Im trying.. with little success, to put as littel as possible into it.

Thats what I thought on the batts, just wasnt sure. And that for sure is something I will be looking into asap. I keep looking at those Turnigy Lipos. It seems they are getting good reviews.?. I can get 2 2s 5000's for what I paid for 1 Reedy 5000. And heck, even if it last 5 runs, thats longer than one of my Reedys made it... man that made me steam! It got a very slight puff to it. Not sure how bad it was but I was afraid of it. It was in a hard case and showed about a heavy 1/16, not quite 1/8 on both the top and bottom.

Darn economy is really srewing up my play time.....

[Ub Hauled]

Zippy or Rhino Lipos... is that what you talking about?

[tiqueman]

These

http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=9514&Product_Name=Turnigy_5000mAh_2S_30C_Lipo_Pack

[Ub Hauled]

wow.. no wonder they are in backorder... they are a dime a dozen

[tiqueman]

And Ive read A LOT of good reviews...


Seems like the other day I ran across this formula, a few times, about figuring prop rpm, having something to do with your motors KV, your batts mah and/ or voltage... ringin any bells with anyone. Whats the formula??? Ive been trying to find it for the past 15 minutes

[domwilson]

Try FECalc... http://www.rcboataholic.com/fe_calc.htm
It's general and not terribly accurate. But it will get you in the ball park.

[tiqueman]

I tried that. It wasnt what I saw before... because I didnt dl it. And, being a brushless newb as well as having a motor and ESC that I have no idea whats what, the FEC only makes me stare and get frustrated.

[tiqueman]

It was something about taking your motors KV and mult or dividing it by the mah and then mult or dividing that by some number and you got a general rpm number... ? Where the heck did I see that.

Maybe I made it up... I have been thinking about all this a lot lately

[domwilson]

http://www.offshoreelectrics.com/conversion.htm

[tiqueman]

Nope... I just found that a bit ago. But keep trying! LOL

[domwilson]

http://www.props4u.com/prop_chart.htm