5 minute hydro race

[tjsb]

Anyone seen these riggers that run 5 minute races? How are they doing it?

[NativePaul]

Naviga racing? If so we switched from 5 to 6 minute races for hydros back in 2014 or 2015. The general answer is build light and slippery boats with some aero lift and high sponson angle of attack, as the boat is light and slippery it doesn't need a big prop to push it and even for a given diameter Naviga props have less blade area than typical, so you can get good speed by spinning it fast, typically were running more RPM than sprint race boats do, but at much lower current.

We have 3 hydro classes:-

Mini Hydro, 2-3s, for hulls <450mm (<about 17.5") these have a minimum weight limit of 450g, composite hulls from ETTI Raze, Ecomaster Mini Hydro, and H&M MiniMi are commercially available or from artisanal buiilders at races or via facebook, I think all mini hydros are self righting thes days. Optional power limiter set at 21Wh (likely soon to be mandatory) 114g battery if not using limiter which gives 3s 1900mAh or 2s 3000mAh, personally I used 3s 2200mAh with limiter. Motors are 60-70g 2830-2835 inrunner or an outrunner of similar mass the tradeoff here is the inrunner has a higher electrical efficiency, but needs water cooling and that adds weight decreasing the hulls efficiency if your using the light batteries with no limiter you can be watercooled and at the minimum weight so an inrunner is a no brainer, but with a limiter its a tougher choice, KV 3000-3400 for 3s, I've never tun 2s in this class. ESC, for 3s I've used 30A watercooled or 50A uncooled. Driveline is 1.1mm to 1.5mm wire drives, I use 1.2mm, 1.5mm is way overkill but more readily available commercially, 4mm ball bearing struts are nearly ubiquitous, but personally I use 1/8" BB struts for my legacy collection of props. Props generally 29-32mm range depending on KV and type, Dr Props, Tenshock and ETTI make good ones and id rate them in that order, i use modded Octura, but wouldn't if i was starting over.

Hydro 1, 2-3s, no hull length limits, no min or max weight limit, Composite hulls Like ETTI Arcas, ETTI Iceblade, Ecomaster evo2.5, H&M Dr Evil, or artisanaly made hulls at races or via facebook, I think the majoirity of Hydro1s are self righting these days. Mandatory energy limiter set at 60Wh, everyone I know is on 3s, 6200mAh-7000mAh, 2860 inrunners are very popular but some use stubby 36mm inrunners, no outrunners, all boats are watercooled, 3000Kv to 3800Kv. 90-120A ESCs. 1.5mm wire drives with 4mm ball bearing struts are ubuqutous but i perosonally use 1/8" BB struts for my legacy collection of props, props generally in the 35-38mm range depending on KV and type, Dr Props Tenshock and ETTI make good ones and I'd rate them in that order, I use modded Octura, but wouldn't if I was starting over.

Hydro 2, 4-6s, no hull length limits, no min or max weight limit, Composite hulls Like H&M Dr Super Evil, or artisanaly made hulls at races or via facebook, self righting Hydro2s are a small minority as the big boats go over less and with the higher speeds there is more likely to be damage from racing contact or buoy strikes if the do go over so there is less importance to it. Mandatory energy limiter set at 120Wh, everyone I know is on 6s, 6200mAh-7000mAh, 3660 3672 and 4060 inrunners, no outrunners, all boats are watercooled, 1500Kv to 1900Kv. 120-200A ESCs. 2mm wire drives with 4mm ball bearing struts are ubuqutous but I perosonally use 3/16" BB struts for my legacy collection of props, props generally in the 42-45mm range depending on KV and type, Dr Props Tenshock and ETTI make good ones and I'd rate them in that order, I use ABC, but wouldn't if I was starting over.

[tjsb]

Is there a kit I could buy of a outrigger or built one ?

Thanks Tom

[NativePaul]

Kits not really, light and slippery means wood boats don't do well, from my experience switching from good wood to good composite in all 3 classes gave me over 10% more laps with the same gear, and about 20% with more optimised gear. There is only 1 endurance racing kit that i can think of the Mini Hydro RBC fast4ward but its 10 years out of date from the inception of the class and wouldn't be competitive now, but might still make a decent fun boat and is much better suited than the JAE Mini Sprint.

As for built, any composite hull does the building for you, you just need to add the booms sometimes and fit the hardware and electrics, but if your thinking more of an ARTR package Ecomaster regularly sell them and and ETTI sell them from time to time or if you are on facebook check out RC-sails.ro Razvan builds to commission and does a Hydro1 called the phoenix and probably the best Hydro2 called Endgame.

[tjsb]

Thanks I just wanted a 3s rigger that ran longer than 80 or 90 seconds at 60 mph

[NativePaul]

The fast4ward is out then, a mini hydro is only good for about 50 mph no matter what power you throw at it unless you limit yourself to saws on glass water, a hydro1 would suit you better.

Can you build from plans and modify them? Plans for the JAE.12 are available on NE-stuff, and and it's a good size for 3s you just need to move some bulkeads to fit the electrics in and make a bubble canopy for motor clearance, With a 2860 3700Kv, 150A ESC, 3s 6000mAh and detongued x435, I would guess you would get 60mph for about 3.5 minutes on an oval course.

[tjsb]

Yes I've started building riggers for about 30 years ago and just got back into it about 2 years ago. Just never saw anyone get an electric rigger run for more than 90 seconds at race speed. Ill try one of those modern types again I had an r-4 that ran whose than my old style rigger.

Thanks Tom

[sjslhill]

Excellent classes!

[tjsb]

TJS rc outrigger 3s

look at the video on youtube and tell me what you think.

Tom

[NativePaul]

Got a link to it?

[tjsb]

where do I find it?