Brand new to UL1 - Steering and twisting problem

[kwizz]

Hi guys i'm brand new to the UL1 and brushless RC. Spent my time playing with a TS2 but got sick of the hitty missy nitro.

Took the UL1 out for first run yesterday, from the off it took me a little while to work out the submerging issue they have but got the hang of it. Next it was running really wide corners in fact didn't turn left at all, changed the rudder angle and height setting on servo arm and got a bit more manoverablity but no-where near what I need. Been reading threads and noticed I gotta lower the prop strut to at least 1" which i've changed but not tested, because went to lake today and had a problem connecting transmitter to receiver ( but sorted that out back home).

The big issue I have which I can't find in the threads is when I set the boat away it pulls hard to the right even with the trim turned all the way to the left and the boat travels through the water twisted crab like. I'm not sure what it is I have to do to stop this, maybe the strut change I made may bring the nose down and straighten it out but doubt it.

You guys know your stuff so any ideas?

[m4a1usr]

Have you done the normal inspections to make sure the issue is due to hardware config? Check to see if your Tx has the steering end points wide open. Start there. Next see if the servo arm is set at the center of travel. The arm should be pointing either straight down or straight up depending on how the linkage is connected/routed. And the rudder should be at a neutral run angle with the arm pointing at the 90 deg setting. Check those first.

BTW congrats on joining OSE. Lots of very knowledgeable folks here.


John

[kwizz]

When you say neutral angle on the rudder, is this angle taken from the boat mounted on boat stand or from transom. When on stand it's perfectly straight up and down, but looking at the transom the back edge of the transom leans in at the top, so if i lift the nose of the boat up to correct the transom angle then the rudder angle is in towards the boat.

Also any idea why the boat tracks twisted, I understand that there would be some prop torque but no-where near what it's getting?

[m4a1usr]

My comment about the neutral setting was related to direction of travel for the hull. The rudder should be set for zero deg or any angle off the center position. If the rudder is offset or not neutral then you need to adjust the turnbuckle/ rear nylon piece that attaches to the rudder bracket.

As far as the hull crabbing or side travel that could be due to one of several reasons. The turn fin might be bent or adjusted incorrectly. The hull might be worped/twisted. To check either you will need to set the hull on a flat surface and allow the turn fin to overhang on one side while the prop overhangs the other. Or you can take the prop/driveline out.


John

[kwizz]

Thanks for your help mate, i'll try that. Does the angle of the turn fin i.e set forward or back effect the straight line performance of the boat?

[m4a1usr]

Thanks for your help mate, i'll try that. Does the angle of the turn fin i.e set forward or back effect the straight line performance of the boat?

If its set way off it will cause the right sponson to dig in or lift out of the water depending if its set too far down or up. The way to check it is again, set the hull on a table with the ride pads and bottom of the strut being the points of contact There is a visable bend line or machined press deformation mark in the aluminum. It runs front to back. This line will be your reference and should be parallel to the surface of the table the hull is sitting on. Remember if you adjust the strut in the future due to new prop, strut depth readjustement, ect make sure that the turn fin angle is once again adjusted to reflect that change. The natural ride angle of the hull in the water is what the turn fin needs to be set for.

John

[kwizz]

I've just just went thro all the things you have mentioned.

The settings with the TX were fine, as for the servo arm it was set back slightly but not enough to limit or impair steering performance. So I've unscrewed the arm switched the servo on and set trim to centre, and replaced the arm without having to adjust the turn buckle.

Looking at the geometry of the hull it looks fine, but on inspection the turn fin is a queer shape, quite severe.
From the side looks fine, and the angle set is the turn fin top edge is flush with the mounting bracket.
But from the front looking along the underside the turn fin curls in and upward with angles, the pics of other boats i've seen on this site mustn't be using this stock fin as they are straight up and down.

LOL feeling a little mentally challenged with the dymamics of the UL1 at the moment!

[kwizz]

I understand what your saying now and it makes sense. I'll work with what you've told me and test the boat out on the lake tomorrow.

Thanks mate.

[m4a1usr]

The UL1 turn fin does look sort of odd when compared to others being used. It curves at the bottom and turns inwards towards the hulls centerline. But the design does keep the right sponson planted during a turn. Here is a old thread you might want to read thru with lots of good information. http://forums.offshoreelectrics.com/...ad.php?t=13933

John

[dana]

Btw the ul-1 is not meant to turn left at all

[ncornacchi]

I've had great success with the straight turn fins....no lift on the corners and I can actually get a better right turn, which stills needs a lot of room........ I especially like the Kintec Racing fins.....i had one that was pulling once and i noticed that my rudder was a couple of degrees out of perpedicular to the hull, but i'm sure you've already checked that...............

[kwizz]

I hadn't on my very first run, when i brought the boat in i noticed it was out. Straightened it but didn't change the pulling or the crooked drive forward.

Going out within the hour to try out the new settings with the prop strut height and turn fin angle, hopefully bringing the nose down might make it track better.

Hopefully the lakes defrosted a bit more so i can really let rip!!

[kwizz]

Well been out and didn't learn too much really.

boat still pulls quite hard to the right, front end was still bobbing about. I lowered the prop strut some more but back end seemed to be riding high, so I raised it quite high and found I couldn't get the boat to launch at all kept submerging and couldn't get on to plane. Put the prop strut in about middle height and could get on to plane.
My friend who came along who's got a SV27 brought as assortment of different props, so I tried a 2 blade 40x51. Totally amazing difference for launching never submerged once, really fast acceleration but bucked about a bit up high end. Tried moving the turn fin really low then high but didnt find a noticable difference.

[bigwaveohs]

The UL-1 manual has a lot of good setup instructions...

[kwizz]

followed all the instructions and the boat still travels twisted.

Went down to lake again today tried a few things which didn't stop this twisted travelling, water was quite choppy so took a weight from my TS2 and put it in the nose to see how it would go, kept the nose down quite good actually, and didn't submerge with the 40x51 2 blade on.

next time i go down i'm taking the fin off and taking it for a gentle run to see if it's the fin causing the problem.

Been watching loads of Youtube vids and not one UL i saw pulls right or rides twisted.