Submarining Whiplash!

[sailr]

I have had a heck of a time getting the CG right on my new whip! I have had to add a lot of weight to the front, even using very heavy hyperion G3 5500 batteries. It's still tail heavy. Now the weird part...it should be light in the bow...right? Well it submarines like crazy and it takes a lot of work to get it up on plane. There are 3 other whips in the club and we are all set up identically with the hardware, motors, strut, rudder, strut depth and angle, etc etc and none of the other guys have this problem. Another members and my boat were built by the same guy! Go figure, eh? Once up on plane, she boogies. The guys in my club are really pretty salty FE boaters and they're baffled.

I should add we are all running them as LSH, P spec boats with UL-1 motors on 4 cells.

Any idea about the submarining problem? Do I need a bigger prop to pop it up or what? I'm using a detongued 642. One of the other guys is using and M545.

[domwilson]

Have you played with the strut height and angle? Got any pics of the back?

[Heath M]

most hydro's will tend to nose dive off a standing start if you don't give them full throttle.,My whiplash would do it. If giving it full throttle off the start doesn't work try the 45mm prop.

Heath

[detox]

TOO MUCH weight in the front. Screw COG

[sailr]

We all checked the strut depth and angle while at the lake yesterday. It is correct. Identical to the other whips that don't seem to have any submarining problems.

Have you played with the strut height and angle? Got any pics of the back?

[sailr]

yep, next time out I'll try the 45. Although detongued, the 642 must be creating too much lift.

most hydro's will tend to nose dive off a standing start if you don't give them full throttle.,My whiplash would do it. If giving it full throttle off the start doesn't work try the 45mm prop.

Heath

[sailr]

Thought about that. Put in some much lighter flightpower bats and it was worse!

TOO MUCH weight in the front. Screw COG

[detox]

Move COG back towards stern if your prop does not help get it on plane.

[detox]

Weak Lipos?

[sailr]

Nope.

Weak Lipos?

[Jeepers]

way to much weight in the front, you shouldn't have to add that much weight to the nose. pull the cg back and angle the propeller down a tad to lift the transom. dont forget that the whiplash was designed as a nitro boat thats supposed to be 5lbs RTR .

[T.C.]

I am confused?
If the COG is where the boat needs to be balanced and where it will run the best.
Then it should not make a difference what weight it takes to balance the boat or if the weight is in the front or back of the COG, just so it's balanced.
I would think the COG is the COG?
I wouldn't think gas or electric would make a difference?
T.C.

[Jeepers]

I am confused?
If the COG is where the boat needs to be balanced and where it will run the best.
Then it should not make a difference what weight it takes to balance the boat or if the weight is in the front or back of the COG, just so it's balanced.
I would think the COG is the COG?
I wouldn't think gas or electric would make a difference?
T.C.

A certain amount of lift is built into the hull to plane off a certain amount of weight if the weight is more than the hull can lift it will run wet and exhibit those problems. CG is going to have to change, so is the amount of lift.

I have seen MANY Whiplash 20s, 40s set up as nitro at the GAS/ Nitro nats and they don't submarine

[detox]

My UL-1 would submarine VERY easily if too much lipo weight was added up front.

[egneg]

If the boats are the same then there is only one variable left .... the driver.