Comment by Ritchie on September 10, 2010 at 11:43am

Reverse thrust I have no effective on my mind that I could implement easily.
Landing patterns however, I think TJ is spot on but the landing area would have to be of a certain size in every direction. A setup I had considered for mission planner software was waypoint based. With a "string" of waypoints with landing point and approach start at either end. With two waypoints between to help you setup for a gentle plop rather than a splat. My worry now is that without getting the wind right (predetermined points), this plop will be much more likely to be a splat.
However, what if TJs landing preparation could be used to lay out the waypoints for my "landing strip" idea. The landing strip could have definitions to the airframe to become more specific and allow better control during landings.

Comment by Tj Bordelon on September 10, 2010 at 11:52am

@Maik - Wish I had you at the first test flight. The prop unscrewed itself! I run a feedback loop so the error tends to build up slow enough. But I did have to add a delay of 1 second- if you cross over from forward to back it waits for 1 second with no throttle to allow the prop to slow down.

Comment by Maik on September 10, 2010 at 11:59am

Are you using the ESC braking functionality? Most car ESC, and many plane ESC do have that.

Comment by Tj Bordelon on September 10, 2010 at 12:01pm

@Ritchie - I have specific landing bearings that effectively define runways. Right now there's a waypoint for the landing spot, and a list of up to 4 approach bearings. It picks the closest one. Now for landing patterns, I have 2 modes. One is beam follow, the other is radius follow. I radius follow around the landing point, then set up a new radius waypoint which is at the end of the runway, offset perpendicular by the radius length. So after I'm done orbiting and measuring winds, I fly to the other radius which lines me up with the runway. I added one last tweak which returns to beam following along the runway when I'm pointing perpendicular. That helps in cases when the wind is blowing and the last turn following the radius doesn't quite line you up.

Anyway, reverse thrust is pretty easy- just get a model car speed controller and allow your throttle values to go negative from a speed PID loop.

Comment by Tj Bordelon on September 10, 2010 at 12:01pm

Yep- using the breaking functionalty. Mostly because I am forced to with this ESC.

Comment by bGatti on September 10, 2010 at 12:07pm

I imagine your dynamic negative thrust is about half of your static negative dynamic thrust; if the plane is moving forward, and the props are churning backwards, surely they must be stalled?

Comment by Tj Bordelon on September 10, 2010 at 12:30pm

@bGatti - I'm sure the prop is somewhat unhappy and stalling and/or otherwise being inefficient. Heck, it's running the airfoil backwards! But it does produce drag very well, and plenty of it.

Comment by Tj Bordelon on September 10, 2010 at 1:34pm

Can anyone give me some landing stats for their plane? Mine: From 200 feet up going 30 mph it takes me 600 feet to land.

Comment by APaperClip on September 10, 2010 at 2:01pm

I'm probably going to show how much of an amateur I am (if I could even be ranked as highly as that), but I figured I'd give my two cents, however devalued they may become.

What about some sort of arresting gear?

Comment by Ritchie on September 10, 2010 at 3:11pm

I keep forgetting yours isnt a normal one :D
Once mine can be trusted, I'll start doing landings and give you all the data.

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