I need help

[Carl]

Hi all,

I have just finished my Paddle Steamer CURLIP.This is a small paddle steamer based in East Gipsland Vic.(www.paddlesteamer.com.au).My problem is,when ever i run at full scale speed she tends to lean.I like some help to find the reason for this strange behavior.

Thanks to all

Carl

[derekwarner_decoy]

Hi PD's & welcome Carl.........

A few photographs of your model CURLIP and also your model CURLIP at speed may assist to understand the issue

Basically any model will self wright .... ...however the metercentric point of balance [MPB= 1] must be lower than the axis of rotation [AOR =2]

When [1] and [2] are equal in height a mass irrespective of shape & size does not have the propensity to return to the original set position....

Think of your hull + superstructure as a single element....inside you need a pendulem effect that is lower than the AOR to provide your vessel with self wrighting capabilities

With paddle vessels which are usually of low speed.... ...I doubt that hull speed is causing your issue......however clearly could be a combination of a light breeze coupled with a [rudder] turning moment + an MPB that is marginally too high......

Is there any component of mass within the hull that you can lower?....eg., if electric & your battery stands upright...try laying the battery flat & retest......Derek

[Roderick Smith]

I am not a modeller, but I do read all the technical threads as they appear.
There are many posts about stability in the forum: I am just not sure how you find them fast with the search engine.  Try searching on 'stability'.
Here is a thread on the commissioning of the replica:
www.paddleducks.co.uk/smf/index.php?topic=3459.msg18624#msg18624
There were two rc Curlip models there.  Is one of them yours, or is yours a third?
What scale have you used, and where do you sail it?

Roderick B Smith
Rail News Victoria Editor

[Carl]

Hi Derek
Thank you for your prompt replay.I am not very good playing around with Paddleducks jet,Hope my pictures coming over to you alright.
 I like to send you a few pictures of my CURLIP Also I have dropped my battery lower but this made no difference.There is one more thing i can try, is to change my battery pack to double AA.Apart from this i have no idea what to do next.

Carl

[derekwarner_decoy]

Hi PD's.....Carl......your picture/images are OK

Try removing the vessel superstructure & retest the vessel & keep your test criteria  .....constant............Derek

[Carl]

I am not a modeller, but I do read all the technical threads as they appear.
There are many posts about stability in the forum: I am just not sure how you find them fast with the search engine.  Try searching on 'stability'.
Here is a thread on the commissioning of the replica:
www.paddleducks.co.uk/smf/index.php?topic=3459.msg18624#msg18624
There were two rc Curlip models there.  Is one of them yours, or is yours a third?
What scale have you used, and where do you sail it?

Roderick B Smith
Rail News Victoria Editor

Hi Roderick,

Thank you for your speedy replay.I have had not much luck jet to find a answer to my problem. The two CURLIP'S you referred to are not mine.I now of one of them but not the other.I will send you a picture of mine. Thank you so much for trying to help me i have to wait and see.

Carl

[mjt60a]

Hi there, just a couple of thoughts, may come to nothing or may point someone else in the right direction...
..is the model perfectly level when it's at a standstill?
..does it always lean the same way? (to port, it looks like on the pictures)
..could you put the wheels on opposite sides and see if anything changes? (find out if one of them has more 'traction' )
..are both paddlewheels immersed to the same depth?
Now, I wouldn't have thought that last one was all that critical (as the effect of 'pulling the whole paddlewheel downward' when the floats are leaving the water should be countered by the floats entering the water and 'pushing the same wheel upwards' ) but on a PBM edwardian steamer kit I have, it does have a worrying effect if even the slightest breeze causes the model to lean one way or other!
Very attractive model, by the way 

[Roderick Smith]

Is that amount of lean really a problem?
In full size, PS Marion has a permanent list to port.  PS Ruby was regarded as a tender vessel, my experience to Renmark is that it has a slight list, and always to port.

If you are launching at South Surrey Park (Box Hill) on any Sunday, I could call up for a few minutes: solely to watch, not to solve anything.

Roderick B Smith
Rail News Victoria Editor

[derekwarner_decoy]

Morning this Easter Sunday to all PD's  ....Carl...in image 0035 we see

1. Clearly the batteries appear lay down flat & on centreline axis
2. The motor is to STDB......the pulley & o-ring reduction drive is to PORT...& yet Curlip still lists to PORT

Ballasting a small model vessel can be a very delicate task...... but Curlip appears to have adaquate freeboard

3. As mjt60a has suggested...check the vessel for level [PORT to STDB condition] in the bath........
4. You will be amazed at what little transfer of mass will result 
5. What is the electronic component in front of the motor?.......does it have much mass?.....it could clearly be moved a little to STDB

Keep us posted with your progress........the sun is approaching the yardarm........Derek

[Carl]

Hi Derek
I have finally fixed my problem by lowering the COG with means I have changed the battery pack to tripple AA's.My original batteries weighted 630gr.and now the weight is only 325gr.Thanks again to all you helpfull Paddlers for solving my problem.
Regards
Carl

Hi PD's & welcome Carl.                     

few photographs of your model CURLIP and also your model CURLIP at speed may assist to understand the issue

Basically any model will self wright .... ...however the metercentric point of balance [MPB= 1] must be lower than the axis of rotation [AOR =2]

When [1] and [2] are equal in height a mass irrespective of shape & size does not have the propensity to return to the original set position....

Think of your hull + superstructure as a single element....inside you need a pendulem effect that is lower than the AOR to provide your vessel with self wrighting capabilities

With paddle vessels which are usually of low speed.... ...I doubt that hull speed is causing your issue......however clearly could be a combination of a light breeze coupled with a [rudder] turning moment + an MPB that is marginally too high......

Is there any component of mass within the hull that you can lower?....eg., if electric & your battery stands upright...try laying the battery flat & retest......Derek