Scale Left Sponson Lifting

[Duke Mordja]

I have a left sponson lifting at speed. The wind was pretty calm today, and left side came up. I think I may have corrected left turn that caused it.

Take a look at the last part of video and see what you think may help (besides weight in sponson)

http://youtu.be/u2iMUeS7jt4b

 

[Jerry Dunlap]

I think you will find many guys are running lead in the left sponson of scale or sport hydroplane designs. I know that's not the answer you were looking for.

JD

 

[Roxyflash]

What side is the rudder mounted too?

 

[Duck899]

I agree with JD with weight in the left sponson to counteract the torque of the engine. You will also find the turn fin can play a part in this as well. I'm talking the angle of the sweep back. Also, make sure the turn fin is absolutely dead straight with the hull. If you correct left and the sponson lifts, then its not straight. Try shimming it one way to see what it does. My smoking joe could hold the left sponson right out of the water all the way down the straight and was the funniest thing ya ever saw. Added some weight (12 ounces) and tried different turn fins and it improved a lot. A higher lift prop will help too.

 

[Hydro Junkie]

One of the guys in R/C Unlimiteds had a boat that was carrying the left sponson in the same manner described by Rob. What he found, after almost trashing the boat in frustration, was that the shoes were too deep. The right sponson was being held down by the skid fin while, at the same time, the left side was being supported by the left shoe, prop and engine torque. After shaving down the shoes, the boat ran great.

 

[wayne middlemiss]

It fliped because you went left

It was pretty extreme how much left rudder throw ( EPA ) do you have

i agree with what greg said, over steering and then a left hand correction not good.

 

[Duke Mordja]

It fliped because you went left

It was pretty extreme how much left rudder throw ( EPA ) do you have

Only a very small amount. Must be too much. Obiviously. Will make it less.

Possibly will add a little weight to left sponson.

Thanks

 

[Duke Mordja]

its hard to tell but was the boat turning right then you corrected left ? or just going straight and added a little left

it shouldnt be that extreme

After watching the video (about 20 times) on full screen, It looks like I may have been turning right a little then corrected left. Usually if I need to correct left, I get off the throttle. This time, I did not. Good thing for nylon screws for the wings.

 

[Duke Mordja]

What side is the rudder mounted too?

Starboard side as mfg, suggests.

 

[Duck899]

You need to get the boat to track straight. A very well set up hull will allow left turn corrections at high speeds without rolling over and tripping. If your in a race and get in a situation like that in the video, you may cause a lot of destruction by another boat running over you. Its going to take a lot of lead. Buy those stick on weights and tape them on top to try it out.

 

[Duke Mordja]

You need to get the boat to track straight. A very well set up hull will allow left turn corrections at high speeds without rolling over and tripping. If your in a race and get in a situation like that in the video, you may cause a lot of destruction by another boat running over you. Its going to take a lot of lead. Buy those stick on weights and tape them on top to try it out.

The boat does track straight with rudder straight to the hull. Turn fin square to hull, but may be too vertical before the curve. Would angling the fin in 5-10 degrees have any impact on left turn? It is not one of the things we want to test too many times.

 

[Duke Mordja]

That may be all it was if the boat is going right and the fin is hooked up and you add left they can roll very violently like you see in vid

Its more a technique thing than setup I would leave it unless it becomes a regular problem

I would agree with you. The boat was moving along pretty good with my new fuel from John Otto. Boat was faster than ever. Now I have to learn to drive it again.

 

[wayne middlemiss]

its like the gp boat warlord @ kilo trials this weekend gone he was feeding a touch of right rudder to keep on coarse and you can see the deflection of water come of the turnfin when it was happening and carrying the right sponson @ 163mph and blew off.

 

[Jim Caldwell]

Angling the T/F will make it worse!

 

[Mike Hughes]

Dont tuck the fin. It will get worse. I know you dont want to add lead. But we all do to the left sponson to get rid of the tork. You will have problems when ever you go left. In the heat of battle you may panic and turn too much and over she goes. On my scale I run about 12-14 oz of lead in the left front tip. After you figure out what you need, it is best to get some lead shot and mix it up with epoxy. Drill a 1/2 hole near the nose and pour it in. Put a piece of tape over the hole and stand the boat on the nose. After the epoxy goes off you can peal off the tape and it perfect.

Mike

 

[Duke Mordja]

Had a pretty good race this weekend at the Badger pond. I drove her pretty hard and had no problems with my left sponson coming up. It must have been my over correction left that made her role last week. I did correct left during the race at times, but didn't over do it.

 

[GRoth265]

Its not uncommon to add 12 to 14 ounces to the left front. I agree with the left turn. If your running a hook turn fin that's kind of the price you pay for being faster in the corners. If its a blade more tuck or different fin. Greg

 

[big al]

Duke, I agree with all these guys adding weight works, but you hate to do it. turning left is definitely the cause, I know from experience. Next race I'll look at it with ya see what we can come up with.

AL

 

[Duke Mordja]

Purely driver error on this one. Saved it-barely.

Reducing left rudder even more next time out.

:mellow:



:huh:

:blink:

:unsure:

 

[Samuel Hagan JR]

That's amazing!