I just did a little research, and it looks like duct fans are around 50% efficient. Did anyone try them out during lunacy?
I know i saw a couple of teams use them at the CO regional. Personally, our team tried them but we found that we just couldnt get enough lift
We (1771) used 2 fans on our 2009 robot, and they provided a big difference.
Here’s our 2009 Robot, “Puffy”. It was a thrust boost, but we did not quite get the competitive edge we had hoped for.
Fans seemed to vary based on implementation, but from what I could tell they varied from having a negligible effect on some robots to a large difference on others. Implementation was key.
71 had some nicely executed ‘assist’ fans in 2009. Should be some pictures around here somewhere. I recall inspecting their robot at Chicago and St. Louis that year.
Ducted fans are interesting. Our robot had two ducted fans that turned with the crab modules, so they assisted regardless of which direction the wheels were pointing. They were approximately six inches in diameter and with the correct motor they could generate about eighteen pounds of thrust each at 30,000 rpm. They were made of carbon fiber and were very strong and light in weight. They are used in large, high end model airplanes.
We could not use the supplied motor,which is a very special high rpm design, so we used CIMS. We tried different gear ratios, but the best we could get was in the 8000 to 9000 rpm range, which degraded their performance considerably, but it was amazing how much breeze came out of those little fans. With the traction of the Lunacy surface being so low, we figured any assist was better then nothing.
I don’t know how effective they were providing thrust, but I think our human player that year mentioned that the fans (if positioned higher up on the robot) would slighty throw off his aim when throwing the orbit balls.
1729 used 2 16" props (shown here).
They were incredibly effective and allowed us to pin our opponent during autonomous and have our human player fill their trailer at his convienience.