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O-1 Meadowhawk Ornithopter

WARNING: Being a true ornithopter, the Meadowhawk is a little tempermental. Please see Operation section second from the bottom of this page.

Description:
A true ornithopter, inspired by the recent dune replicas I've seen around, and created in pursuit of general ornithopter "technology" in Stormworks: a field I feel is somewhat unfortunately obscure given the engine's uniquely strong and stable handling of mechanical components. My intent with this project was to produce a small, practical, true ornithopter with the fewest cosmetic sacrifices and smoothest flight I was able. Of note: this particular ornithopter is accomplished without any XML editing.

Features in this version:
-70-80 knot cruise speed
-Variable Angle of Incidence (left monitor)
-Variable stroke offset (right monitor)
-20-30 minute battery life
-Decently responsive controls
-minimalistic but useful avionics suite

Suggested edits:
If you want a longer range, it would be very easy to replace the twin medium batteries with a single small battery and a modular engine diesel generator. A small one or two cylinder engine generator would grant this thing enormous range, but wasn't included here because frankly I thought it was more fun as it is.

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Operation:
- Takeoff -
Advance the throttle VERY slowly at first and be ready to pull harshly back on the elevator. The wings produce deceptively high static thrust, and WILL try to nose you over. This effect reduces drastically after the first twenty knots or so.

Note: You may wish to shallow the blade angle of incidence (touch and hold the top of the left monitor) for takeoff. This will significantly reduce the nose-over tendency, but will also significantly reduce climb performance and increase vibrations.

- Climb -
The Meadowhawk's climb performance is surprisingly good at the default angle of incidence, but will fall off very quickly at shallower angles. Climb between 0 and 20 degrees nose up at full throttle and at the default (steepest) blade angle.

- Cruise -
The Meadowhawk was balanced to vibrate as little as possible while at its steepest blade angle, but you may wish to shallow it in cruise. Physically speaking, this is roughly akin to steepening prop angle on a variable pitch propeller, or selecting a higher gear in a car. The ornithopter will gain ten to fifteen knots flying straight and level with a shallow angle, but climb performance will be much poorer than at the steeper angle.

Note: Being entirely electric, the Meadowhawk's performance will diminish as its battery drains.

- Descent and Landing -
Descend at 15% - 30% or so power. The Meadowhawk will maintain a fairly predictable glide slope down to very low throttle settings, but will fall abruptly if wingbeats stop altogether. Air in stormworks is very dense, and the flight controls are designed for oscillating wings.

- Special Avionics -
The Meadowhawk includes two touchscreen monitors. The left monitor alters the angle of incidence of the blades. The right alters the vertical offset of the wing stroke. Both are increased and decreased by tapping the top or bottom of the screen. The stroke offset modifier defaults to a value that will clear the ground when taking off, but you may wish to change it in flight. Changing the wing stroke offset drastically alters the center of thrust. See the third video for a demonstration.

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Design takeaways (for other ornithopter builders):
- Control surface-based wings (where the control surface provides the angle of incidence) definitely seem to be the best strategy so far. I suspect fully mechanical wings might be able to outperform them on a very large scale, but haven't come up with a two-axis mechanical wing stable enough to test that.
- The speed of wing strokes is fundamentally limited by the tick rate. Wings can be made to beat very quickly, but if the physics engine doesn't have time to calculate thrust from them over the course of a stroke, you're out of luck. You may even start to experience negative thrust. Favor slower strokes exerting more force when possible. Also note that surfaces closer to the tip of the wing will necessarily be moving faster and generating more thrust.
- It is possible to extract a lot of stability from hinges when running at 1:2 or 1:4 ratios. My best luck has been at 1:2 with large, heavy-ish, high-lift/drag wings.
- Shallower blade angles become useful sooner than you would think, so if you're trying to come up with a way to get steeper ones (as I was in the beginning) you may be barking up the wrong tree. In general, a system that feathers the wing incidence automatically with speed is probably ideal.
-Regarding shake: This ornithopter uses direct counterweights attached to each wing, moving opposite it. This definitely helps, but the way it helps is kind of unpredictable. The current configuration is as good as I could get it, but I don't doubt a much better system is possible. It may be better to counterbalance the wings with opposing wings rather than weights, as drag will be more consistent than weight for changing blade angles. I did not have much luck with this, however.