Delta Force Vortex Hydro, Feigao XL

[spicedcrab]

Hi,

22" Vortex Hydroplane
Feigao 7XL
Barracuda 125
6v BEC
Two Thunderpower 4cell 3300 lipo's, (parallel)
.150 Flex
Speedmaster strut
Speedmaster rudder

Im building it now and my question is were should the COG be?

Currently with one lipo in each sponson, the COG is about 1 3/4" behind the rear edge of the sponsons. Is that a good place to start?

Thanks,
John

[Jeepers]

thats alot of motor/power for a little hydro! thats gonna be a rocket or a plane!

[spicedcrab]

Yes your prob right, I already had this power system that I pulled from a delta force 25.5" mono and I want to try the hydro out this weekend so thats why I put it in. I will be propping small and seeing if I can keep it upright.

were should my COG be? (i have never ran a hydro before)

Thanks,
John

[Fluid]

The default CG for sport hydros is as close behind the sponson transoms as possible. Some boats even run best with the CG forward of this point, but that is rare. On a small overpowered boat like this I'd get it as close as I could. Mount the motor as far forward as practical. Ditto the packs. Mount the servo as far forward as you can and use a long pushrod.

As far as a prop, even an x438 or y536 will yield very high speeds for such a little boat. Set the Barracuda on its lowest timing.


.

[Heath M]

Make sure you get some vid of this, it's going to be wild LOL

Heath

[OJ racer]

Wow! Mine does about 45 w/ an X-power 100a, Feigao 10-turn 540L, and two 7.2 volt packs in series. You should watch out, that thing's gonna be insane.

[justneedspeed]

Newb question. How do you measure COG?

[Heath M]

Measure from the back of the sponsons towards the transom

Heath

[Jeepers]

spidercrab the hydro in my avatar is 25" long, on 4s1p 4350mah 8XL x440 prop, it was well into the 50mph range and its a handful. your vortex is gonna be WIIIIILD!

[OJ racer]

Get us some video asap. I wanna see this thing in action!

[spicedcrab]

almost done

im getting it ready this morning, hopefully i will get a test run in later today. if i get an extra hand i will try and get some video also.

[OJ racer]

I'm not so sure about putting the center of gravity far forward in the DF22. I was intrigued when I saw it here so I tried it in mine, it went totally submersible. One time when I hit the throttle it dove down at least a foot! Thank goodness I sealed it well.

[Jeepers]

with that much power I would start CG way forward as well.

[spicedcrab]

I made the 1st run, I took it real easy on the throttle to get a feel for how it acts. most of the time on the straights I was about 3/4 throttle and almost no throttle while I was turning around. I did make two passes at full throttle and it felt pretty stable, I was using a carbon 40mm prop. I had almost no steering at all, I will have to get a turn fin on it. After running there was no warmth to the lipos or ESC and the motor had just a hint of warmth. Since everything was cool and stable im going step up to an X637 and push a little more speed. Overall I loved the way that it handled I just have to get that turn fin on so I can turn.

Here is the video, Sorry the camera man was not very stable.

http://www.youtube.com/watch?v=vTunGt1OE3A

[ace028]

Looks nice, speed is addicting huh?