3 ms·

It's an impressive achievement for an amateur. He has separate motors for vertical and horizontal flights, which simplifies the design, but creates a rather ba

It's an impressive achievement for an amateur. He has separate motors for vertical and horizontal flights, which simplifies the design, but creates a rather bad inefficiency, the vertical motors create lots of drag during the horizontal flight. Maybe it's not a big deal, I'm not sure. Making motors rotate would add weight for sure, thus reducing the range.

the__alchemist 1y ago
Adding a tiltrotor mechanism is surely not worth the added complexity and weight, in this case. You're right though on the added weight and drag from having separate motors and props.
- tsungxu 1y ago
  And also iteration cycles slow down, adds cost to development and qualification if making them in-house for larger prototypes.
tsungxu 1y ago
It's actually not a terrible inefficiency. With this config, the cruise motors and prop are optimally sized for cruise - which gives non trivial gains to both eta for propulsive motor efficiency and prop efficiency. Vs a tiltrotor/wing/body in which the cruise motor has to do double duty as lifting motors. Given it takes anywhere from ~4-7x more power to hover (depending on disc loading) than to cruise, you can see how the motors are not in an optimal throttle/rpm band in this case. Archer's CTO Munoz has actually said this publicly.
tsungxu 1y ago
And the weight (and drag) penalty is ~5% given the actuators and subassemblies for tilting don't come for free either. This is also the most the penalty will ever be as electric motors continue increasing in specific power, and quite rapidly this century so far.
xnx 1y ago
Very similar design already used by Wing. I'm guessing they did a fair bit of analysis and modeling of the cost, range, complexity, safety, etc. etc. tradeoffs before settling on what they're using currently. https://en.wikipedia.org/wiki/Wing_Aviation#/media/File:Wing_delivery_Vuosaari_3.jpg https://en.wikipedia.org/wiki/Wing_Aviation#/media/File:Wing...
- tsungxu 1y ago
  Two impressive things about Wing's design are 1) load paths are designed to break the airframe in controlled ways 2) the 4 blade props have alternating shorter and longer blades for quieter aeroacoustics Adam Savage did a video tour of their factory recently, worth a watch
  - xnx 1y ago
    > Adam Savage did a video tour of their factory recently, worth a watch Thanks! https://www.youtube.com/watch?v=_BXm6dTHvY0 https://www.youtube.com/watch?v=_BXm6dTHvY0 I'm a big Waymo and Wing fan, but hadn't seen that.
    - tsungxu 1y ago
      It's great, check out the Slo Mo guys video from that same tour for the prop smoke vortex https://www.youtube.com/watch?v=5yaAFLpLmVg https://www.youtube.com/watch?v=5yaAFLpLmVg
amstan 1y ago
Shameless plug: https://aliptera.com/ https://aliptera.com/ Tilt-rotor on all 4 motors with an extra twist: the wing shape adds to the lift in vertical mode, so you can use smaller motors, so they're more efficient even in horizontal mode.
- joha4270 1y ago
  What exactly do you mean by > the wing shape adds to the lift in vertical mode Wings require airspeed to work, which there presumably aren't a lot of in vertical mode.
atemerev 1y ago
Looks like an autogyro. Which are quite efficient.
btbuildem 1y ago
There are lots of DIY variations on the theme -- here's one: https://hackaday.com/2022/08/22/optimising-a-rc-tilt-rotor-vtol/ https://hackaday.com/2022/08/22/optimising-a-rc-tilt-rotor-v...

the__alchemist 1y ago

Adding a tiltrotor mechanism is surely not worth the added complexity and weight, in this case. You're right though on the added weight and drag from having separate motors and props.

tsungxu 1y ago
And also iteration cycles slow down, adds cost to development and qualification if making them in-house for larger prototypes.

tsungxu 1y ago

It's actually not a terrible inefficiency. With this config, the cruise motors and prop are optimally sized for cruise - which gives non trivial gains to both eta for propulsive motor efficiency and prop efficiency. Vs a tiltrotor/wing/body in which the cruise motor has to do double duty as lifting motors. Given it takes anywhere from ~4-7x more power to hover (depending on disc loading) than to cruise, you can see how the motors are not in an optimal throttle/rpm band in this case. Archer's CTO Munoz has actually said this publicly.

tsungxu 1y ago

And the weight (and drag) penalty is ~5% given the actuators and subassemblies for tilting don't come for free either. This is also the most the penalty will ever be as electric motors continue increasing in specific power, and quite rapidly this century so far.

xnx 1y ago

Very similar design already used by Wing. I'm guessing they did a fair bit of analysis and modeling of the cost, range, complexity, safety, etc. etc. tradeoffs before settling on what they're using currently. https://en.wikipedia.org/wiki/Wing_Aviation#/media/File:Wing_delivery_Vuosaari_3.jpg https://en.wikipedia.org/wiki/Wing_Aviation#/media/File:Wing...

tsungxu 1y ago
Two impressive things about Wing's design are 1) load paths are designed to break the airframe in controlled ways 2) the 4 blade props have alternating shorter and longer blades for quieter aeroacoustics Adam Savage did a video tour of their factory recently, worth a watch
- xnx 1y ago
  > Adam Savage did a video tour of their factory recently, worth a watch Thanks! https://www.youtube.com/watch?v=_BXm6dTHvY0 https://www.youtube.com/watch?v=_BXm6dTHvY0 I'm a big Waymo and Wing fan, but hadn't seen that.
  - tsungxu 1y ago
    It's great, check out the Slo Mo guys video from that same tour for the prop smoke vortex https://www.youtube.com/watch?v=5yaAFLpLmVg https://www.youtube.com/watch?v=5yaAFLpLmVg

amstan 1y ago

Shameless plug: https://aliptera.com/ https://aliptera.com/ Tilt-rotor on all 4 motors with an extra twist: the wing shape adds to the lift in vertical mode, so you can use smaller motors, so they're more efficient even in horizontal mode.

joha4270 1y ago
What exactly do you mean by > the wing shape adds to the lift in vertical mode Wings require airspeed to work, which there presumably aren't a lot of in vertical mode.

atemerev 1y ago

Looks like an autogyro. Which are quite efficient.

btbuildem 1y ago

There are lots of DIY variations on the theme -- here's one: https://hackaday.com/2022/08/22/optimising-a-rc-tilt-rotor-vtol/ https://hackaday.com/2022/08/22/optimising-a-rc-tilt-rotor-v...