Hooking left

[cyberhoops]

In some testing of a 1/10th scale hydro the boat has a tendency to hook sharply left while turning. It will be turning left normally, then pretty much without warning it will cut in sharply. It does not happen all of the time, but it seems to be toward the end of the turn (or maybe when the speed drops a bit?)

In the first test runs it was lifting off a bit so the strut was lowered about 1/8 inch. That seemed to have cured the problem and the sponson are staying down.

The turn fin is straight - and in alignment with the sponsons
The rudder is a 0 degrees of camber.

This is not much information, but any ideas on what might cause this effect and how to adjust for it?

[Flying Scotsman]

What hull, hardware and where is it positioned. A photo would be great.

Douggie

[cyberhoops]

The boat is a 1/10th 1990 Oberto...

Here are some pictures of the current setup.

Speedmaster rudder
Aluminum skid fin

[m4a1usr]

By the looks of the strut angle in one of your photos I would change that first. It appears to me to be set with too much down pitch. I dont know what size motor you are running but it looks like maybe a 1515 something? I can only guesstimate but the strut appears to have something like 4 degrees down. Try running it a bit more shallow. Too much down angle can allow the transom to "blow out" or lift out when turning. Maybe try lessening it a degree if possible. That boat appears to be a plywood hull build, which means it could be a little heavy, and that with a less then ideal COB could easily combine with turn blow outs. Its common in riggers. I should know.

John

[JimClark]

It is a straight shaft John first I would make sure you don't have too much rudder movement back off on your trim. If you have too much throw in the servo you could easialy get it to hook. Is this Mark Beaty boat that you bought from Darin Jordan?

Don't change things much that boat should be set up pretty well as it is.

[Randy Naylor]

Sounds like the servo is a little weak to me. What are you using and whare is the CG?

Also is there any kick up in the rearof the hull.

[kevinlew211]

im second one after Randy with weak servo or linkages

[cyberhoops]

To answer some of the questions raised..

This is the Mark Beaty boat that I purchased from Darin Jordan, it is mainly plywood construction and fairly heavy.

It is a straight shaft, wire drive.

It does have quite a bit of throw in the rudder. I could see that if the boat slows down and it has full rudder the turn radius would increase pretty quickly. It might all be driver induced (especially since it does not happen all of the time)

The CG is 4 or 4.25 inches behind the back edge of the sponsons.

I will double check on the linkages.

I will say the boat does run nicely - and it could just be the driver.

[JimClark]

CG is probably too far back When I ran 1/10 in CT and ERCU the CG was abut 1 inch beghind the sponson. Are you running lipos?

[cyberhoops]

The boat is running with Lipo, and they are tucked in as far forward as I can get them.

[Darin Jordan]

That boat does NOT have a straight shaft... It has a .078 Wire Drive, and it can be setup with a much flatter angle... The brass stuffing tubing is larger than needed and houses teflon liner inside that should still give a straight appearance, even with the strut set flatter...

[Darin Jordan]

It is a straight shaft John first I would make sure you don't have too much rudder movement back off on your trim. If you have too much throw in the servo you could easialy get it to hook.

I agree with Jim here... Slow down the servo and reduce it's throw... remember, that boat was setup to run around a 1/8th mile or so course with 30-35ft radius turns... you don't need much rudder to do that.

Prop can make a big difference here as well... which one are you running on there... I had good luck with a Graupner 45mm 2-blade for starters...

[JimClark]

What size Lipo

The boat is running with Lipo, and they are tucked in as far forward as I can get them.

[cyberhoops]

4900mah Lipo, 2 of them in series - and currently running the Graupner K45 prop. (The motor is a Proboat Blackjack)

I am leaning toward driver error now maybe related to having more throw than needed in the rudder, or just plain turning the boat more sharply than needed. When running our test laps we don't have turn markers and we are probably doing more like 20' radius turns (maybe less).

Overall the boat is running nicely -

[Darin Jordan]

4900mah Lipo, 2 of them in series - and currently running the Graupner K45 prop. (The motor is a Proboat Blackjack)

I am leaning toward driver error now maybe related to having more throw than needed in the rudder, or just plain turning the boat more sharply than needed. When running our test laps we don't have turn markers and we are probably doing more like 20' radius turns (maybe less).

Overall the boat is running nicely -

Jim,

When the season starts, we can work on building up to a better prop... that one works well... but I know how to make that boat come alive! ;) You might need to add some weight to the nose to make it work, however... ;)

[cyberhoops]

We ran the boat again yesterday, with the driver being a bit more aware of turn radius toward the end of a corner.... perfect (at least in my opinion)

[Darin Jordan]

We ran the boat again yesterday, with the driver being a bit more aware of turn radius toward the end of a corner.... perfect (at least in my opinion)


Execellent... I'll look forward to meeting you in battle here in a couple of weeks! The Miss DeWalt is all ready to go...

[froggy]

OOh a howard boat against a beatty boat. Not to mention Darin knows where the Oberto might be lacking since he drove it too. Those are both Excellent boats though. Look forward to hearing about you racing.