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Old Mar 21, 2011, 09:40 PM
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wparsons's Avatar
Canada, ON, Markham
Joined Aug 2008
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Get the offset rudder bracket from kintec racing, that seems to help as much as anything else (or more).

The rudder angle really only effects it while turning, tucking it in will tend to lift the transom while kicking it out will lift the nose. When it's going straight it doesn't really do anything.
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Old Mar 21, 2011, 11:24 PM
"Every boy has a dream to fly"
Airplanekid333's Avatar
Fort Collins Colorado
Joined Sep 2009
510 Posts
speaking of physics, I don't get how and off-set rudder eliminates the bounce, does the thrust from the propeller hit the rudder and makes it bounce?
I hear that the off set bracket is the best way to get rid of bouncing and i will plan on getting one.
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Old Mar 22, 2011, 06:28 AM
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Rusty Old Fart's Avatar
Newcastle, Australia
Joined Nov 2010
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lower the prop depth a couple of mm's at a time.

Try that.

Lots have used the offset that wparsons mentioned it works, why ???
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Old Mar 22, 2011, 07:24 AM
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Canada, ON, Markham
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A good starting point for prop depth is to have the bottom of the strut even with the bottom of the sponsons. The easiest way to do this is to set it on a table and lower the strut until it touches.
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Old Mar 22, 2011, 10:36 AM
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United States, NC, Charlotte
Joined Sep 2009
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The prop is pushing water onto the rudder, the bottom of the rudder is flat so when the prop wash pushes over the rudder it makes the rudder create unnecessary lift. The hull then gets forced down because the rudder is creating lift then the hull starts unloading/loading meaning every time it hits the water it bounces back up and starts the process all over, the rounded off area behind each step on the sponsons doesn't help either. If they were more at 90* angles instead of rounded that may help also. The offset bracket gets the rudder out of the way of the prop wash by offsetting it and pulling it more forward and more inline with the drive dog. If you round the rudder lower leading edge as well as the very bottom of the rudder which is flat and run the correct cg the bounce should go away. This is just MY take on it, I maybe 100% wrong. I was able to get rid of the bounce still using the inline rudder, but I was running a PB1800kv stiletto motor and a grim 40x52/3 prop the strut was dropped and the batts back further towards the transom. I know when I took the boat out on it's maiden it was a VERY bad bounce, especially on 5s lol. I used the inline rudder for a while, then I got bored and changed EVERYTHING lol.. Running a CC 1800kv outrunner now.

Here's my madian, you can really see the bounce on 5s:

Proboat Miss Geico (2 min 20 sec)




* Congrats to the OP on your new boat, and welcome to the wonderful world of FE!
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Old Mar 22, 2011, 01:27 PM
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Australia, QLD, Brisbane
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Quote:
Originally Posted by Airplanekid333 View Post
speaking of physics, I don't get how and off-set rudder eliminates the bounce, does the thrust from the propeller hit the rudder and makes it bounce?
I hear that the off set bracket is the best way to get rid of bouncing and i will plan on getting one.
i bought my MG 2 days ago cant wait for it to get here.
it must be a new design because the add said comes with off set rudder.?
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Old Mar 22, 2011, 05:21 PM
"Every boy has a dream to fly"
Airplanekid333's Avatar
Fort Collins Colorado
Joined Sep 2009
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@wilsta67 Where did you order it from? i just got mine 5 days ago and it doesnt have an offset rudder.
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Old Mar 22, 2011, 09:05 PM
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wparsons's Avatar
Canada, ON, Markham
Joined Aug 2008
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They all come with an inline rudder, you have to buy an aftermarket bracket to offset it.

http://www.kintecracing.com/Miss_Geico_Upgrades.html

Get version 2 if they're in stock.
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Old Mar 22, 2011, 10:14 PM
"Every boy has a dream to fly"
Airplanekid333's Avatar
Fort Collins Colorado
Joined Sep 2009
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I'll rack up 25 bucks and buy this off set rudder.
Below the off set bracket there is Shear Bolts, should i get those too?
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Old Mar 22, 2011, 10:23 PM
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Diesel6401's Avatar
United States, NC, Charlotte
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Quote:
Originally Posted by Airplanekid333 View Post
I'll rack up 25 bucks and buy this off set rudder.
Below the off set bracket there is Shear Bolts, should i get those too?
YES!

I use a small zip tie instead, but you want some sort of shear bolt on the lower hole of the rudder, that way if you hit a ufo the shear pin will break and kick the rudder up and no damage.
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Old Mar 23, 2011, 12:59 AM
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Australia, QLD, Brisbane
Joined Sep 2010
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Quote:
Originally Posted by Airplanekid333 View Post
@wilsta67 Where did you order it from? i just got mine 5 days ago and it doesnt have an offset rudder.
i ordered it from here rc planet.i was going to get it from ose but they had sold out. there add also says comes with offset rudder
http://www.rcplanet.com/Pro_Boat_Mis..._p/prb4100.htm

http://www.offshoreelectrics.com/pro...+Catamaran+RTR
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Old Mar 23, 2011, 12:54 PM
"Every boy has a dream to fly"
Airplanekid333's Avatar
Fort Collins Colorado
Joined Sep 2009
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@Diesel6401 Oh so its like a breaker when the rudder hits a rock in the shallow area? thats convenient.

@wilsta67 Keep me updated when you get your MG
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Old Mar 23, 2011, 01:35 PM
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K.R.Joye's Avatar
Romeo,Mi.
Joined Sep 2002
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You need a small Garmin GPS to validate your speed improvements as you make changes to the boat. Great to see a young guy into the RC hobby, keep up the good work!
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Old Mar 23, 2011, 02:44 PM
Memento Mori
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United States, NC, Charlotte
Joined Sep 2009
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Quote:
Originally Posted by Airplanekid333 View Post
@Diesel6401 Oh so its like a breaker when the rudder hits a rock in the shallow area? thats convenient.
BINGO

Their are 2 bolts on the rudder, the top bolt will be the stock metal bolt and pivot bolt. The lower bolt will be the shear bolt or zip tie. When you run over something it breaks the lower bolt and swings up preventing damage to the rudder and more importantly the transom.

* I started with a sv and didn't use the shear bolt, when I ran something over under the water which I could not see (I think it was a small log) the rudder tried to pull itself through the transom and left a crack across the transome, ever since then I always use shear bolts
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Old Mar 23, 2011, 06:45 PM
"Every boy has a dream to fly"
Airplanekid333's Avatar
Fort Collins Colorado
Joined Sep 2009
510 Posts
@ K.RJoye It is a great hobby! I have been doing rc airplanes in the last 8 years and been RC boating for one week and love it just as much. I wish I can get a GPS but can't.

@ Diesel6401 Oh jeez I am going to get shear bolts for sure because i ABSOLUTELY don't want to deal with a cracked fiberglass transom, the lake i run at has a shallow rocky area and other random obstacles that can take out my rudder.

Update: I just went for a run with the new adjustments i did, and NO BOUNCE!...Repeat!...NO BOUNCE! It was the best go around i've had so far! There was no wah wah wah at all, and it was hydroplaning perfectly with a 7 foot rooster tail and the cooling line shooting out of the side nicely. It was nice!
For those who can't recall, the new adjustment was, the strut was 1mm above neutral level, batteries hanging a half of an inch behind the trays, and the rudder slanted inward.

I just finally realize i had no marine grease at all, and the shaft need to be maintained ASAP so i ran to the hobby store and got Hob-E-Lube moly grease.
The "expert" at the store said this should work great and i went home and greased the shaft. Then went for another run and it went well, and found tiny bits of amount of grease splattered onto the wood and the Tupperware lid.

Did i put too much in the shaft or did the guy at the store sell me the wrong thing?
Thanks again guys!
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