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>> a phenomena called “ground effect” to significantly boost flight efficiency I’ve been following rctestflight’s efforts to make an R/C ground effect vehicle

>> a phenomena called “ground effect” to significantly boost flight efficiency I’ve been following rctestflight’s efforts to make an R/C ground effect vehicle https://m.youtube.com/watch?v=x617U3s3lcc&t=670s https://m.youtube.com/watch?v=x617U3s3lcc&t=670s The interesting thing he’s experienced (there’s many videos, i don’t have a single succinct link to share) is that staying in ground effect is hard. If an r/c plane has enough power to take off, then it has enough to break out of ground effect, and almost certainly it will break out. The suggestion then is that something like the ekranoplan might have been able to fly normally to some extent. I don’t know how much the aerodynamics of rc planes scales up though, e.g. i don’t think KF airfoils are a thing in full size aircraft but they’re super effective and popular in rc scale.

pohl 4y ago
I have no idea how any of this works, but I recall reading that the ground effect threshold is some proportion of the aircraft's wingspan (half, I think?) so it could be that it's more difficult for a model just because it's smaller. (Maybe that was the wisdom behind making the spruce goose so big?)
WJW 4y ago
I imagine that it is easier to keep a big plane in ground effect than a small one because the relative size of the boundary layer to the size of the airplane is a lot larger with increasing wing area. The Soviets had several working prototypes that managed just fine while carrying heavy loads, and there's plenty of videos of glider pilots effortlessly gliding along for hundreds of metres in ground effect over runways and the like. Also no offense to rctestflight's impressive skills, but his aerotech skills seem to be mostly self-taught (he studied "applied film at business knowledge according to linkedin). There would be a huge different between what a talented amateur can achieve and what a team full of trained professionals could build. Staying in ground effect seems like an ideal job for a flight computer to manage btw, autopilots never tire and always stay focused.
- meheleventyone 4y ago
  He actually uses a flight computer for his most successful published effort.

pohl 4y ago

I have no idea how any of this works, but I recall reading that the ground effect threshold is some proportion of the aircraft's wingspan (half, I think?) so it could be that it's more difficult for a model just because it's smaller. (Maybe that was the wisdom behind making the spruce goose so big?)

WJW 4y ago

I imagine that it is easier to keep a big plane in ground effect than a small one because the relative size of the boundary layer to the size of the airplane is a lot larger with increasing wing area. The Soviets had several working prototypes that managed just fine while carrying heavy loads, and there's plenty of videos of glider pilots effortlessly gliding along for hundreds of metres in ground effect over runways and the like. Also no offense to rctestflight's impressive skills, but his aerotech skills seem to be mostly self-taught (he studied "applied film at business knowledge according to linkedin). There would be a huge different between what a talented amateur can achieve and what a team full of trained professionals could build. Staying in ground effect seems like an ideal job for a flight computer to manage btw, autopilots never tire and always stay focused.

meheleventyone 4y ago
He actually uses a flight computer for his most successful published effort.