Does anyone know the ratio betwen liftoff power consumption and mid flight power consumption?

[SoEFoil]

@ELEVATE.rocks

It depends a lot on the Foil Wing and effectivity of the prop, but a good value ist 1100W cruising 25km/h and 1600-2000W for T/O

Thanks for your data. According to your figures (flight power consumption / take-off power consumption) = 55 to 69 %.
Previously I had read that this ratio was 60%. To increase the battery life, it would be interesting to know what makes the 15% difference … wind direction, chop over the water surface, propeller total surface, pitch ratio…?? Battery voltage going down along the session ?

@millesth

Peters build: 25% Anybody else experienced such low consumption ?

That is impressive !

@Peter

Starting power consumption is ~1,8kW, flying speed at 25-30km/h is 400-500W(!) I was very surprised with that! A friend of mine with 85 kg needs 30% more power.

@Peter explains the “secret” of his setup a bit later: He seems to be using a “tandem” configuration (Please Peter correct me if I’m wrong). As both wings provide positive lift, the centre of lift of the plane is moved 20cm more aft compared to a traditional setup. The rear wing provides lift (plus balance with far less drag) that sums up to the front wing surface to allow early take-off with a “small” 600cm2 front wing.

@Peter

I know that many are creating stability with negative angle of the rear foil, but this creates drag that I don’t want to have at higher speeds. So my center of gravity is slightly in front of the main foil and thats enough for me. I go even little further, my rear wing creates lift in higher speeds, so the angle of attack is decreasing with increase of speed, and the system plains itself. To reach >20 knots

On the right picture we can clearly see that the rider’s CG (his belly button to simplify) is nearly above the mast that is totally unconventional, sign of a rear wing providing positive lift which in turn forces the plane Neutral Point to move backwards…

HUGE CON: pitch unstable reaching 25 knots - experienced by the GONG Hellvator kitefoil in 2016, reason the tandem setup was abandoned in 2017 although loved by beginners for the added stability below 20 knots.

@Peter

As I said you can only reach that low power consumption when you want to fly with nearly zero stability. Maximum efficiency leads to zero stability. You have to find your own sweet spot for this.