The advantage is you can have as little lift as you need. Just a tiny angle of attack will give a tiny lift so you can still advance. Such an tiny angle of attack is not possible on a soft sail as it is already flogging.
Getting the connection to the actuator is a little tricky, you could use slip ring to allow the sail to rotate indefinitely. But I would guess we might want to look at guessing of the absolute angle of the sail. So we can see it gone two tuns clockwise relative to the boat, I should turn back the other way a few times to unwind it.
Ah, so moving the momentum up the mast it can make the control surface smaller and/or using a shorter boom, that would also reduce the need of countering ballast?
Not totally convinced about this since there is a ‘horizontal turning’ momentum not only a ‘vertical twisting’ momentum. Both are not improved by moving the control surface higher on the mast?
I probably did not phrase that right
@iampete, don’t worry to answer that post, its academic.
But please get me ready to sail this Wednesday or Thursday since weather seems favourable here.
I can’t really remember and would be super happy with a refresher
(I really did spend 1h to search this thread to find your golden posts on how to it works, no luck)
Maybe we switch this around: you give me a task to sail so you can make simple cause and effect conclusions?
I was planning to sail in auto from wp1 to wp2 and repeat it at beam reach. look at the log and make some conclusions.
. Acro what to do?
. Auto what to do?
Boat is sailing backwards and I am confused.
I can post my configuration so you know what’s going on?
Thank you,
What I need to move forward is a refresher about setting my throttle stick position when enter any flight mode above Manual.
This is my setup.
If I recall correctly, I start in manual mode and then the THR stick has no effect on the sail/wing angle, then when I like to move to Acro or Auto modes, then I should move the THR stick to the top position. Right?
Then I should observe if the boat is sail forward or backwards. Right?
If sailing backwards - then what to do?
Printing small wing sails looks like it should be feasible. Here’s a prototype 100mm section at 1/2 scale of the target 1400mm sail where I’m experimenting with getting the structural reenforcing integrated. The section weights 33g.
Here its two steps forward and at least one backwards.
When sailing last week it was over 5m/s so I used the small D wing sail for the first time.
Seems, unlike the large A wing that makes the boat sail neutral on the rudder (even up to over 5m/s winds), this wing makes the boat tend to steer in to the wind. Creates a need to compensate with rudder and this causes lots of drag. No point in sailing above manual mode like this.
I am not sure but I think of this like sailing a windsurfer, move sail aft-wards and the board will steer in to the wind, so maybe too much area aft. I was trying to cut a corner and using the same wing flap as when sailing the A sail but it should be 55% smaller or have a shorter boom to provide relative equal moment on the wing. I have made a smaller flap now that might fit better (using same boom and same ballast weight). Will test next time wind calls for it, and hopefully the boat will be neutral on rudder.
For the first time the wing sail makes it back and forth between wp1 and wp2 by its own a couple of times (˜beam reach). Very light wind 0-3 m/s so used Wing A. Put the throttle up and let it stay in Auto mode for a long time. When periods of no wind it mostly drifted around but sorted it self back on course when wind picked up, most of the times. It does not sail backwards, its correct direction. But sometimes I think I noticed when ripples etc made it draft backwards then, code put rudder in opposite direction so it gets back on course again - cool.
It was just once I recall it got in to a situation it could not get out of on its own. I think at some point when wind shifted it decided to tack up wind towards wp, not sure.
No huge insights from the log, this is trarget turn rate vs actual. The tarket getting quite abit larger than the actual so it might be worth increasing gains. But it could just be your going slow and that the best it can do. Very hard to tune this stuff without a fairly constant speed.
Hi,
Since its hard to sail any boat remotely not seeing/experiencing the wind direction, I am looking at options to get the direction to pilot. At present in the HUD we can present the
wind_vel and
wind_dir
and this will be displayed as numbers.
Even though this information is very good, I have found it totally insufficient for my poor brain to use as guidance when sailing.
I need some kind of arrow showing where the wind is coming from vs. the boat current heading to guide me (true or apparent wind direction both can work).
I have a kakute f7 aio board with FPV -
is there any way to display Wind Speed and Wind Direction via the FPV goggles?
Seems the items to display are very limited using MissionPlaner…
The easiest path would be to do a module for MAVProxy in python. Should be possible in mission planner too, but the code is a little harder to get into.
wow, it would be super useful if you succeeded making any one of those options work
B t w this display make more sense to me. Showing where wind is coming from and wind speed. If can swop between true and apparent would be great but any one is okay.
Cool with OSD!
this means you already wrote the code and now there is some process with checking it and if okay it will be merged into rover next version, ‘master’.
The apparent wind is what the wind instrument reports with no calculations right? For example when sailing with the wind the wind speed will appear and be reported slower.
Yeah, hopefully will be in soon, if not I can also do custom builds.
Yeah, straight from the sensor (well actually filtered). Unforunatly the OSD arrow thingy only has 16 positions so only 20 deg steps. I think this is just a limitation of the type of OSD, although we might be able to do something better with lines, but that would be a much bigger change.
The apparent wind is now sent back over MAVLink, can find it in the status tab, AppWndSpd and AppWndDir should also be able to assign to hud and quick tab.
Well 20 degrees shown in OSD arrow will still be a great improvement and help compared to now.
. I think I successfully flashed with the latest .apj file (see my screenshots).
. I should see the AppWndSpd and AppWndDir in alphabetical order in Status respectively Quick right?
. Cant see them…
