rigger pulling to the right ?

[John Finch]

I found the 2 blade props on my rigger walk less than the three blade props. Tried any 2 blades?

 

[speakerboy]

he guys thanx again for your answers ..

Nick .. there is a cloud of water comminf from the left side , close to the black spot of the motor mount .. there is the water comming out ..

Terry . thanx for your comment ..its running high and dry .. may be even to high at the back .. will see how this handles in mirror flat water ..

John .thanx for your reply .. i do have the 2716/2 blade as well .. a good prop on this boat but a little slower .. i have a couple on their way over here to see if i can make one that will meet the speed of a 3 blade ..

first i will fix the sponsons .... B)

thanx guys !

Jeroen

 

[dr gary turner]

Guys , thank you for replying , realy appriciated , there are some good tips and tricks here ..
Steve, i can shimm the strutt , i do run 5 cells pack and i have a massive strong servo , so this is an option .. thanx

Preston , i think i understand what you mean .. i do have the A.brown turnfin here , but by the looks i liked the Virginia crafman much better and started with that one . i am thinking on rising the AOA a bit .. i will come back about that later .. thanx

Mike .. i must have wrote that down with other intentions . i am not steering left to make a turn .. i only steer a tiny to the left to make a small correction , for example : making a turn and go in the straight after bouy 3 .. what i do is let the boat go wide by it self and becouse the boat turns right a little by it self i ended up at bouy 4 perfectly . the water is wide behind the oval couse so no problem there . now making the turn from bouy 4 to bouy 6 .. no problem there but getting out of the turn right at bouy 6 i have to head straight to bouy 1 . the water here is narrow to the shoreline becouse the oval is close to the shoreline .. i can't let it run wide at bouy 6 so i will never reach bouy 1 without making a correction to the left ! and there you have it , i have to steer a bit to the left . at 80 mph you dont want that .. just a tiny to much and the boat is in a majure water splash ... ended up like driftwood ....

i do have sucha fancy radio so i will play with that ! thanx for your answer .

Kelly thanx for the good eye .. i will show the details below ..

Nick ..if i toe in the right sponson , i will change the angle of the turnfin aswell ? thats what you want ? so the boat might track more straight ? does make sense. but what are the side effects ?

Gary , that will make my AOA on the left sponson more flat right ?

Buck , i do run a flat strutt (bottom) i also have a sharp strut leading and trailing edge , why do you think the A brown turnfin will work better ?

some more info ... i have pics of the rigger at : jeroentune find "my boats " and scroll down for the pics of the rigger ..

i did some messurments of the sponsons to the tub to make sure what we are talking about :

front left sponsons boom to the tub is : 5 1/4 inch

rear left sponons boom to the tub is : 5 5/16 inch !

front right sponsons boom to the tub is : 5 11/32 inch

rear right sponsons boom to the tub is : 5 5/16 inch

messured that . i must say that Kelly has great eyes .. ! conclusion is that my left sponon has a to in from 1/16 inch , and my right sponson has a toe OUT , a very small one but its a toe out !

the AOA on both sponsons is 3 1/2 degrees . i dont have any water comming from the sponsons in top speed .. i do see somewater spray at the front of the rear sponsons .

again i like this turnfin in oval racing it hold amazing and i can make full speed turns , with a 13 pound boat at 80 mph .. i find that impressive ! i will see if it need some sharpning .

i dont eant to do some more angle of attack on the sponons ..i have a pair of new ones comming with a AOA af 6 degrees .. just to test ..

so whats the best to do with the sponsons ?

Jeroen

That is right and the boat will go straight!!!!!! Why??????? Because the left sponson will have more resistance in the water than the right and it will "PULL" the front of the boat to the left making it go straight. The shim trick has been around for YEARS!!!!!!!!!!!!!! GTT

 

[speakerboy]

Thanx guys for all the help .. i did some work and straighten the Sponsons and setup . Also sharpened the turnfin just a bit .. the boat is ready to go will post results soon .

thanx again

Jeroen

 

[speakerboy]

He rigger addicts ,

i just came back from the pond and did some testing .. the rigger still had the same setup , i only changed the distance between the booms to get a correct parralel sponson setup .

result .. it only got worse .. i dont know why but the boat turns real great .. by it self ... i have to steer to the left to get her going straight .. i did test this with several 2716/3 blade props .. the differ from pitch , cup and size (round ears ) but all gave me the same problem ... fun part is , i have it only if i go faster than 82 mph... any speed under the 75 mph it tracks straight . i added 2 degrees left steering and than it was tracking straight . problem went away ..but its not the right solution . this not heat racing just SAW setup ...

if i swap props with a 2716/2 blade .the boat looses some speed , ended up with 77 mph , but , it tracks straight and turns perfect , it runs like a heat racer , the setup is perfect , i hear the front sponsons tickle the water .. but no water is comming of the front ore rear sponsons .. its running real dry .

is there a change i have to less rudder in the water in top SAW speed ?

Jeroen

 

[AndyBrown]

Jeroen,

Nice looking boat!!

It appears that you are running a collet drive. If so, be sure you have enough gap between the drive dog and the strut. The dog could be making contact at maximum speed/thrust. This will cause a torque reaction to the hull.

I didn't notice if you made the angle of attack adjustment that others suggested.

We run a 2.5 mm to 3 mm differential between the left front tip and right front tip.

With the right set the highest.

You may want to give the CMDi fin a try. Dick makes a beautiful fin that works on many boats but I've seen it cause pulling on our SG/SGX hulls.

 

[Raydee]

Pulling to the right is just about the most annoying habit I have encountered in RC boats. I have a hydro that pulls to the right on me and it drives me insane. I noticed with a fin change that the pulling went away. You may want to try removing the turn fin all together and see if it still pulls to the right, at least you can eliminate the fin as the culprit.

 

[speakerboy]

Andy , thank you for your answer , i usame you recognize the collor scheme . i love it all the way .

i do run a collet drive .. i run a 3/16 th gap between the strutt and dogdrive .. i cant find any wear out signs on both of them . there is a teflon washer between them and that one also is not damaged .

both sponsons do not have been chimed . both are still in the angle .. i can try to add a shim under the right front boom to move her up a little and see whats happening .

i all ready have a CMD turnfin .. i have to sand it in shape and get the rough sandings of , i also made a mount for it so it will mount on my rigger easy .. i will give it a test run .

i tested a v967 prop .. it has radical reactions to my boat .. but it was wicked fast .. the water was to short to get her at full rpm . i hope to receive one of your props soon ..

Raydee .. thanx for the hint . i will try to do a run without fin .., see what happens (other than crashing it in the banks ...lol ) i allready made a small saw fim from carbon/ kevlar . i wil test that one too ..

Jeroen

 

[Tom v.d Brink]

It would have been better to set up your sponson angles as well before testing again.

I do advise you do this before trying other things.

 

[Marty Davis]

Pulling to the right is just about the most annoying habit I have encountered in RC boats. I have a hydro that pulls to the right on me and it drives me insane. I noticed with a fin change that the pulling went away. You may want to try removing the turn fin all together and see if it still pulls to the right, at least you can eliminate the fin as the culprit.

You are one of the few that I have seen that really analyzes things correctly. That is the way to find out the contribution of almost anything on our boats. That is also a great way to set up a SAW boat to see that it is running without having to put in a lot of rudder, etc. I have even seen the BEST SAW guys run their boats that way - e.g, Andy....

Good job.....

Marty Davis

 

[AndyBrown]

Pulling to the right is just about the most annoying habit I have encountered in RC boats. I have a hydro that pulls to the right on me and it drives me insane. I noticed with a fin change that the pulling went away. You may want to try removing the turn fin all together and see if it still pulls to the right, at least you can eliminate the fin as the culprit.

You are one of the few that I have seen that really analyzes things correctly. That is the way to find out the contribution of almost anything on our boats. That is also a great way to set up a SAW boat to see that it is running without having to put in a lot of rudder, etc. I have even seen the BEST SAW guys run their boats that way - e.g, Andy....

Good job.....

Marty Davis

I have used that method several times to help isolate the cause of a pulling boat.

 

[Marty Davis]

Pulling to the right is just about the most annoying habit I have encountered in RC boats. I have a hydro that pulls to the right on me and it drives me insane. I noticed with a fin change that the pulling went away. You may want to try removing the turn fin all together and see if it still pulls to the right, at least you can eliminate the fin as the culprit.

You are one of the few that I have seen that really analyzes things correctly. That is the way to find out the contribution of almost anything on our boats. That is also a great way to set up a SAW boat to see that it is running without having to put in a lot of rudder, etc. I have even seen the BEST SAW guys run their boats that way - e.g, Andy....

Good job.....

Marty Davis

I have used that method several times to help isolate the cause of a pulling boat.

I think that I might have gotten that idea from you or one of the Southern Gentleman guys - don't remember for sure.

Marty

 

[speakerboy]

Thanx for the tips and tricks guys .. will run the rigger next sunday , will do a few passes without the fin and see what happens .. also will run 3 different turnfins , the CMDI , the Virginia crafmans , and a Smaller Saw fin .

Jeroen

 

[Marty Davis]

Thanx for the tips and tricks guys .. will run the rigger next sunday , will do a few passes without the fin and see what happens .. also will run 3 different turnfins , the CMDI , the Virginia crafmans , and a Smaller Saw fin .
Jeroen

Jeroen:

One other thing that you might have missed. The strut should be without ANY angle in it. The larger the boat/larger props require that the strut not have angle in it. When you accelerate with angle in the strut, it transfers weight to the right front sponson and it pulls into the course.

Use a piece of string and place along the c/l of the shaft and project forward to the front sponsons. You should have the angle of the strut the same as the bottom of the front sponsons.

Marty Davis

 

[speakerboy]

Marty . thanx for helping me out .. you put a lot of time in my boat .. realy appriciated , i do understand what you write here but i dont understand how to check the angle ..

do you mean the depth of the strutt ? ore the angle of attack of the strutt ? i missed that one in the translation .. sorry ..

Jeroen

 

[Marty Davis]

Marty . thanx for helping me out .. you put a lot of time in my boat .. realy appriciated , i do understand what you write here but i dont understand how to check the angle ..
do you mean the depth of the strutt ? ore the angle of attack of the strutt ? i missed that one in the translation .. sorry ..

Jeroen

Check the angle of the strut by using a piece of string that you hold exactly on the c/l of the shaft and then project it forward with the other hand. It should be the same depth as the front sponsons. This will tell you exactly the angle in relation to the front sponsons.

Marty Davis

 

[Mike Hughes]

Another option to do what Marty is talking about is to get a setup board. Approx. 18" x 30". MDF works good for this. You will have to cut a slot on the right side for the turn fin to go through. This way you will be able to take the boat and place it right on top of the board. Both sponson and strut will touch the board. Now you will be able to see the angle of the strut compared to the surface of the board. You can also use this board to set up your sponson angles.

Mike

 

[speakerboy]

Ok guys thanx for the heads up .. i do understand that and i do have a table wit ha slot for the turnfin and fot the rudder as well , when i put the boat on the table the strutt is flat with the sponsons . the strutt is 1 mm under the rear sponsons , on the table the rear sponsons are "flying " the ange of atack of both front sponsons is 3 degrees (mirror falt water setup ). in choppy water the stutt has to go higher , otherwise the boat starts hopping , doing that, i also change the angle of atack to 5 degrees .. i will work with the a shim under the right front boom to get that angle a bit higher .

Jeroen

 

[speakerboy]

just trying to get it here .. If i was running the angle of the strutt pointing downwards . lets say 1/32 inch . than we would creat extra lift , and depending on the strutt depth , it can couse the boat to hop arround the course , right ? now IF i was running the angle of the strutt pointing upwards , lets sat 1/32 inch , it wil work less effectively , and it will couse a higher roostertail .. ore are there more negative points on that upwards strutt ?

Jeroen

 

[eric wong]

Thanx for the tips and tricks guys .. will run the rigger next sunday , will do a few passes without the fin and see what happens .. also will run 3 different turnfins , the CMDI , the Virginia crafmans , and a Smaller Saw fin .
Jeroen

If your rigger runs straight without a turn fin, then the suspect is the turn fin.