More weight or more canard angle

[Gary]

What would you Hydro pros rather do to achieve more downward force to the front of a SAW Hydro. Add more angle in the canards or add more weight up front?
I would think the faster the boat goes the more force pushing down would be best. Whereas more weight is always constant during the run.
Boat is a P T Super Sport 45 and the search for more speed has come to a halt.
I think I may have reached the ceiling for this hull but I hope not.

[jaike5]

IMO, the ss45 packs to much air under the hull with todays speeds. So I cut the air bleeds off from the sponson's all he way back on my ss45. and haven't had any blow overs since, running at 55-60 mph.
J.

[Gary]

Hey Jake,
This hull should not have any blow overs anywhere in your mph range so something was way off for that to happen.
I don't want to sound to silly but what are air bleeds ? I never heard of that.

[jaike5]

on the bottom there is a wedge that goes from the sponson heel to 3/4s down the bottom pan edge. Your right , probably much faster, I was estimating.

[Gary]

I have tried MANY canard and weight adjustments, not what you did ,but I think this hull may have reached it's limit for me....or more power is needed LOL

[Fluid]

Realize that Gary has had his boat to nearly 110 mph, so there is no comparison with a 50-60 mph oval setup. The aero of the boat was originally optimized for about 45 mph according to Phil, Gary has done wonders with it. Too much angle on the canards may cause them to stall, adding huge drag but little downforce. Weight is a double-edged sword here, adding weight to move the CG forward may help at speed but it can also make the boat difficult to launch. The center of lift changes as the speed increases, but the CG always stays the same.

Every boat has a maximum speed and he may have reached that. He could try small areo add-ons to spoil the lift over top curved surfaces, wider canard surfaces, or small dams to reduce airflow under the hull. Ultimately he will have to consider a different hull. My modified Aeromarine Shadows were rock solid into the upper 90s on 6S for example. That hull does not trap air like the PT boats, but the latter are better overall oval racers.




.

[Gary]

Thanks for chiming in Jay. I may try the canard approach one more time.....a little taller but same angle. I know that you and myself know this hull is way beyond it's limits but...... When watching the data log and calculating each mph to how long and how fast it is accelerating it will suddenly just stop accelerating 108+.
So question is why ? Lack of power to overcome forces? Hull pulling itself to tight to the water ? Than again it will blow over going beyond this limit so it needs to have more down force to over come that. So that leaves me with needing more power ???
Boat is perfectly balanced right now, ESC lives,motor lives, batteries sort of hate me LOL So as you know one little miss step and it's over the edge.
I don't know why Im so hell bent with this Hydro but 115 is the goal LOL !!!

[Shooter]

Hi Gary. It's incredible what you've done with that boat. Those speeds are unheard of, although I think there was another member here that was over 90mph. In my experience, the key to hydro design is a good balance between weight of the boat and pressure underneath. The later is dependent on speed, so eventually, as Jay said, you will overcome the hull's ability to hydroplane and you will blow off. Air dams work great to limit pressure. Another way is to bleed off the air by venting. If I remember, that hull had two small ribs on the edges of the afterplane that extend to the transom. Venting those would help reduce pressure underneath. It's a fairly common technique used on real hydros.

[Gary]

Thanks Shooter and I will start removing the ribs starting in the rear. Don't want to just take them completely off so a little at a time will do.
I did just just install the carbon fiber canards and added .75 degree more angle and 1/4" bigger so we will see what it does. Lots of weed crap growing in the lake "right in the run path of course" to make any runs so might have to wait a bit.

Tried to pull up an OLD 92mph run on you tube but cant copy and paste the ink.
If anyone is interested It's "Phil Thomas Super Sport 45 Electric" and it was the first hull that eventually got destroyed but it's what started the speed thingy.
New hull is 14mph faster.

[Gary]

Tested today and found that batteries are tired with some odd cells but.... pulled 4 ounces out from front nose and boat still stayed put on water but only managed 102-103. Battery voltage was down to 23v instead of 24 under load so rpm was off as well. So think I'm headed in right direction.

[phil t]

Gary you are fast with that Supersport45. I wonder if the newer Stealth design would be better, It runs great on FE power and has the front canards molded into the hull, you can add some flaps for downforce too. The new hull has no airtraps and dumps air from under the hull, it has the rear mounted strut too.
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[Gary]

I would but the learning curve is so looooong that I really don't want to go down that road all over again. It's taken me years to get here so far and I know this hull very well, and at these speeds every tiny thing I do has a dramatic effect for the worse or a very small effect for the good.
But I tell you Phil....these hulls can take an insane amount of abuse / blow overs at 13lb's of weight and stay together....for the most part LOL !!

My priority right now is my next car race in PA so after that I will replace the batteries and get back on it so I should see a big improvement with that alone.

[Shooter]

I agree. All the boats I've bought from Phil have taken huge amounts of abuse and keep truckin!