why does a lean outrigger sag coming out of the corner?

[Dan_Cousin]

I've noticed this on my boats and know that a click or two rich will fix the situation but I haven't figured out why it does that at that particular time.

The boat takes the corner in lane 2 and stays on the pipe until the rudder is straightened out to make a run down the straight. It seems to sag or bog just when the rudder is straightned out instead of when it is applied or going through the corner when the load would be higher.

Looks like suddendly releaving the load causes the sag.

Anyone figure out why this is?

 

[anthony_marquart]

My engines do this too. Someone told me it was due to the air cooling,.. instead of water. Not so obvioulsy.

 

[John Knight]

The engine is under a considerably higher load requirement in the turns than in the straights. Load = fuel. I know of several racers that have their radios linked up to slightly richen the mixture when the steering servo is activated to the right to compensate for the additional load.

 

[Mike Larson]

Hey Dan... Ive a.21 hydro that actually accelerates in the corner applying just the opposite of your question,... thing is, ive had the situation youve had, with the same boat, and, my solution was a pipe issue, ( shorter) if the pipe wasnt reinstalled exactly right after maintenance( clean up) the boat had the sag issue....... I cant imagine as much as an 1/8th inch making that much difference, but, it does.... at least on this particular boat..... I think, in my limited knowledge of the pipe/motor combination, that the higher rpm situation, ( unloading in the corner) that, i am going past the power band (?) limit of the current pipe measurement, and effectively governing the motor, until it comes back down to a more working sitiuation, ( straights) Whether or not this is effective information based upon my trials you'll have to see..... Tinkering with the 3rd channel in the boat is almost too commonplace for me, sense would dictate higher rpm's requiring more fuel, ie: starving in the corners.....equals give it fuel, but, performance ( rich boat) for me suffers upon, " clicking rich" to get a fast cornering boat, try the pipe a tweak.... worked for me..... There are alot more serious hydro guys around, good luck Mike

 

[John Finch]

I've noticed this on my boats and know that a click or two rich will fix the situation but I haven't figured out why it does that at that particular time.

The boat takes the corner in lane 2 and stays on the pipe until the rudder is straightened out to make a run down the straight. It seems to sag or bog just when the rudder is straightned out instead of when it is applied or going through the corner when the load would be higher.

Looks like suddendly releaving the load causes the sag.

Anyone figure out why this is?

If it's a rigger and your in a turn..... right rudder position is letting the prop carry the transom around the corner. Yes there is drag thru the corners as the boat settles in and the turnfin throws water up in the air, but when you straighten the rudder to come out of the turn.......you add even more drag to the engine as you stop letting the prop run it's desired walk to the left.

 

[Marty Davis]

I woud suggest that it may be a combination of two things.

1. The pipe pressure may not be enough. Your stinger diameter should be .282" (the hobby brass size near this dinension). This provides the perfect amount of pipe pressure to the tank.

2. You may have too much water cooling. It is very important on a .21 engine and if you have too much, the engine will appear too rich when the engine becomes unloaded. Restrice the water flow to about 5 on a standard flowmeter set at 40.

One additional thought is that you can also have a lot of drag by way of the rudder defelction if the turn fin is not very efficient. Approx. how many degrees of rudder does it take to make the turn?

Hope this helps....

Marty Davis