Видео

Firstly I haven't got close to maximum lift yet. Secondly I haven't measured blade pitch yet. And thirdly the blades I'm using are twisted so the pitch varies along the length of the blade.

@@OskarRDA what are the rotors diameter ?

@@bradsamers3014 19.5 ft, they're basically the same as Mosquito XE blades.

It was the easiest way to build. You can use any number of tail rotors.

It's a HTD8M, same as what the Mosquito uses.

Don't forget the hi-viz vest, safety first!!

It's twitchy alright, will be much better with 30kg of battery weight down low. The first version feels like a bus compared to this one, should have it steady in another 10 to 15 minutes.

Thanks, and yes, those are Gyro-Tech blades. Was thinking of Oskacopter for the name.

@@OskarRDA How do you feel the inertia of those blades? Is it comparable to the original once's, greater or smaller?

@@rotor-and-soft I haven't done simulated engine failures in the hover so don't know yet. There are lots of variables that have changed, AUW is less, rotor diameter is more, RRPM is less. I had hoped for a ~20% reduction in power, but can already see that is not going to happen.

Definitely possible, but will need a very specialised motor. Have looked but nothing available yet.

@@OskarRDA To have the necessary torque at that low rpm, a direct drive motor will need to have a very large diameter and will be way too heavy than a smaller motor + reduction.

What's the point, you don't save much weight.

@@yutuniopati The direct drive use fewer parts, it's consequently simpler and you don't need pulleys and belt which can break. It's also offer smoother and more efficient flights... that's the theory in the RC helicopter world...

@@69fel32 As other comment said you will need a pretty large brushless direct drive electric motor to deliver the needed torque at small RPM. Direct drive electric motor are interesting for quadcopter not for mono blade helicopter.

Because the empty weight is so low, changes in pilot weight have a very large effect on the CG. I'm designing around a pilot weight of 80kg (176 lbs), if the pilot is much heavier the aircraft will be nose heavy.

@@OskarRDA With a tail boom that length it shouldn't be hard to counterbalance.

@@Patriottoo2 Possible yes, but then no longer ultralight.

Thanks, the setup is much simpler than before and really easy to set up. The tail has its own battery. You cannot see it in the video, it's behind the tail boom.

Ultralight because you leave the batteries home.

@@UCs6ktlulE5BEeb3vBBOu6DQ It will be ultralight including batteries. What you see weighs 165lbs.

@@OskarRDA What I hate about batteries is you weight the same at landing as take off. Its nice to be light in an emergency. Great job it reminds me of Larry Can fly.

@@UCs6ktlulE5BEeb3vBBOu6DQ Look at it the other way. You start off with an ultralight of 254 lbs and then you have to add 30 lbs of fuel to fly. I start off with 254 lbs and don't have to add any fuel to go flying.

Thanks, the profile drag of the blades is more than I had hoped for and that determines the absolute minimum power. From the tests so far it looks like I'll be able to reduce the power by 10 to 15%.

@@OskarRDA 👍 Why is the drag profile of the blades higher than hoped ?

​@@Ben-Dixey All I did was observe the power measurements, haven't gone into why yet.

In this video the power was 17kW. With the previous version hover power is 21kW and the max power is limited to 29kW. Average power is around 22 to 23kW. After a 15 minute flight the motor temperature is around 86C. On a warm day it goes over 90C, don't want to go higher than that. The battery I fly with is 7.8kWh, so running between 2C and 4C. The battery is luke warm after a 15 minute flight.

@@OskarRDA Interesting... Why do you think it's getting so hot, even if it's way inside it's comfort zone? It's cooling problem of the emrax? Can you remind me at what voltage are you running? rpm?

@@GiovanniEsposito5 The temperatures correspond to the data sheet. At the speed I'm running at maximum continuous power (motor at 120C limit) of a 228 CC motor is 34kW, for a LC motor it's 29kW.

It's an EMRAX 228 HV motor. You can download the specs from the EMRAX webpage.

Thanks, flick me an email for more info.

I'm busy building an ultralight version, that one will be for sale.

Building the next version, full carbon fibre airframe 😉

I limit the motor power to 29kW. Don't know what the motor current is, but with a battery voltage of around 360V the maximum battery current is thus roughly 29000/360 = 80A. The controller is rated at 300A continuous.

Thanks, you can read all about it at www.hfpower.co.nz/Oskacopter.pdf