Small 22" WildThing - To Strake, or not to Strake

[Darin Jordan]

I'm in the process of completing an extremely "tricked out" 22" Carbon Fiber WildThing for FE use and was wondering what people's thoughts are on the need for strakes.

This boat will be used in a very "underpowered" application... basically 2S-Lipos using a ROAR "STOCK" motor (Newer 17.5 Brushless version).

The first one of these I built had strakes and seemed to perform well for heat racing.

This hull will be used for 2-Lap and SAW racing, for now anyhow.

I know that people used to race the WT without strakes on it. Just curious as to whether or not people think it's necessary in this application?

I've attached a picture of the first one I built that shows the strakes I used for that hull.

Thanks,

 

[john v]

I'm in the process of completing an extremely "tricked out" 22" Carbon Fiber WildThing for FE use and was wondering what people's thoughts are on the need for strakes.

This boat will be used in a very "underpowered" application... basically 2S-Lipos using a ROAR "STOCK" motor (Newer 17.5 Brushless version).

The first one of these I built had strakes and seemed to perform well for heat racing.

This hull will be used for 2-Lap and SAW racing, for now anyhow.

I know that people used to race the WT without strakes on it. Just curious as to whether or not people think it's necessary in this application?

I've attached a picture of the first one I built that shows the strakes I used for that hull.

Thanks,

i asked john finch the same question when i built another 32'' hull and he said it was not benificial but you are building a different beast so i would pm him and ask. i met him in maryland over the summer and what a wealth of information he was, pretty kool guy

 

[Ron Olson]

I've got one of Grimmie's WT .12's and it handles just fine without strakes.

 

[Grimracer]

Without for heat racing and with for two lap and saw.

Grim

 

[Darin Jordan]

Without for heat racing and with for two lap and saw.

Grim

That's kind of what I thought... looks like I won't quite have it ready for this weekend then...

Here is what I have done thus far, however...

 

[Darin Jordan]

Update:

Ran the little WildThing this weekend at the District 8 Two-Lap event at Lake Waughop in Lakewood, WA. Improved on the existing 2-Lap N1-Mono record in the process. Was 53.09, it's now 49.75.

Ran the boat without strakes or trim-tabs. Was "fast", but I think it can be faster with some strakes, and can be tuned a little more precisely with tabs, so I'm going to work on adding those.

Which brings me to the next question: Run the strakes parallel to the keel the entire way, or converge them toward the bow, like a more typical strake application?

I've seen it done both ways, with equal success it would seem. Would be interested in hearing your thoughts on which would be the "best" way to go.

Here is a shot of the boat at the two-lap event from Saturday...

 

[John Finch]

Without for heat racing and with for two lap and saw.

Grim

That's kind of what I thought... looks like I won't quite have it ready for this weekend then...

Here is what I have done thus far, however...

Daren,

I have run with and without strakes. If you need the lift you can put strakes right at the keel but just shy of at the keel and be legal. That gives you a basically flat area to run the boat on. Kind of like putting a pad on the keel at the transom and coming to a point about 6 inches forward of the transom. I even tried a 10 degree vee on the very bottom of the boat then changed to the normal vee from that point going up to the sides (chine line). The bottom line is this.................At high speed to set a SAW record you are better to leave the deep vee and balance on the last 1/2 inch of the hull Flat pads and strakes will make the boat skip every now and then and you lose control. If you have a heavy boat and need the lift I would use the strakes close to the keel to ride on all the way to the transom. Just be sure the strakes are not as deep as the keel to keep the boat legal.

 

[Darin Jordan]

The bottom line is this.................At high speed to set a SAW record you are better to leave the deep vee and balance on the last 1/2 inch of the hull Flat pads and strakes will make the boat skip every now and then and you lose control. If you have a heavy boat and need the lift I would use the strakes close to the keel to ride on all the way to the transom. Just be sure the strakes are not as deep as the keel to keep the boat legal.

John,

That makes complete sense. This boat is certainly not hurt by weight... weighs only 1 lb. 9oz completely RTR... batteries and all!

I ran it for the 2-Lap event we had here, and it seemed to sing along just fine and handled really well. I just worry that I may be leaving time in the turns as it could have a lot of extra water contact when laid over into the turn. It's VERY light, but also VERY underpowered. The N1 power rules restrict power to a 27T brushed, or equivalent ROAR legal 17.5T Brushless motor on 6-cells or 2S Lipos. So, I've kept the boat as light as possible, and am just trying to make it as efficient as possible.

I hate to go to the work of installing strakes if it's not going to increase the speeds. Sounds like I may need to just to find out. Testing, Testing, Testing!!

 

[John Finch]

If you want speed in the corners don't add the strakes because they will penetrate the water and that is drag. They are good in the corners to stop the boat from sliding away from the turn if you have problems there. Bottom line is.............anything that is in the water is drag and slows you down. Record trials are the one place you let it all hang out. When we set the nitro oval records there was no water leaving the sponsons in the straightaway. The sponsons were wide to keep them on top of the water instead of digging into the water. Same goes with the mono. sometimes it's faster if the boat is completely on one side thru the corners and on top of the water instead of leaning just a bit and being in the water. The turnfin design can effect how much the boat banks. And although there is a fin in the water, you may still go faster thru the turn because the boat is banked more. test, test, test. A shorter strut will also let the bow run lighter thru the corners. There are lots of things you can do to trim the boat. Test Test.