# Human-Powered ekranoplan

### Help Support HomeBuiltAirplanes.com:

#### Burner117

##### New Member
Hi all,
So ive seen aircraft that were human powered before, the only problem I see with them is that they're enormous. My brother and I have been working on plans for a human-powered WIG Effect vehicle built off of a recumbent bicycle. We've run into a snag while designing the wings of the vehicle since there is so little data on ground effect planes. We've decided on the lippisch reverse delta wing for the overall shape of the wing but we have no idea what its dimensions and geometry should be because we haven't found a way to accurately calculate the lift of the wing while in ground effect. So I decided to consult the interwebs to see if any of you knew a simple way to figure it out.

Thanks- Burner117

#### BBerson

##### Light Plane Philosopher
HBA Supporter
I don't how to calculate ground effect, but I remember that Taras Kiceniuk built a human powered ground effect craft in the 70’s for the Kremer competition.

#### bifft

##### Well-Known Member
I don't how to calculate ground effect, but I remember that Taras Kiceniuk built a human powered ground effect craft in the 70’s for the Kremer competition.
Don't pretty much all human powered aircraft fly in ground effect? What with the huge spans required to get efficiency down to where a human can power it, and the fact they don't have enough power to climb hardly at all, they all seem to fly around 1/4 span or lower.

#### BBerson

##### Light Plane Philosopher
HBA Supporter
His was designed to fly about 6" high. With a short burst to clear the height rule once.

#### Norman

##### Well-Known Member
HBA Supporter
Don't pretty much all human powered aircraft fly in ground effect? What with the huge spans required to get efficiency down to where a human can power it, and the fact they don't have enough power to climb hardly at all, they all seem to fly around 1/4 span or lower.
There are two distinct but related phenomena called "ground effect".

First is span dominated ground effect (SDGE). It is simply a reduction of induced drag that the plane starts to feel 1/2 span above the ground.

Second is chord dominated ground effect (CDGE) which gives a lift boost and is typically considered to start about 1.3 times MAC above the ground.

Some WIGs are designed to fly higher than CDGE but most have wings that don't generate enough lift when they leave CDGE. I can't answer the question but it seems to me that if the wing were just a little too small to fly at the speed that you can pedal, without the help of CDGE, then you would have a self limiting system ie loads of lift below a limiting height and insufficient lift above the limiting high

#### Burner117

##### New Member
Is there a particular size/shape wing that maximizes the CDGE?

#### Norman

##### Well-Known Member
HBA Supporter
WIGs aren't really my thing. I just had to learn a bit about ground effect because it has a bigger affect on the landing behavior of the type of airplane I'm interested in than most others. The Lippisch reversed delta with a huge stabilizer looks pretty good.

#### JamesG

##### Well-Known Member
This thread title makes me picture a huge WIG with hundreds of peddlers on rows and decks like an ancient Greek warship.

#### Starman

##### Well-Known Member
I was thinking the same, wow he's going to need a lot of pedalers.

#### Norman

##### Well-Known Member
HBA Supporter
A WIG uses less power than an airplane of the same weight and speed so if MacCready could do it out of chord dominated ground effect it should be easier to do it in CDGE. The wings are smaller and low aspect ratio so can be lighter. I've heard that CDGE can double the lift but don't know that that was accurate but, as I said, If the wing is just a bit too small to fly above CDGE it will reach a critical altitude and stay there so if it's bigger than you need to get off the surface at all is just inconvenient. Of course at the speed you can reach the wing is going to be huge so 2X the wing area could be a big deal.

#### Starman

##### Well-Known Member
A WIG uses less power than an airplane of the same weight and speed.
But it usually needs more power than an airplane in order to take off, ie unstick from the surface, right?

#### JamesG

##### Well-Known Member
What about a WIG that keeps its propulsion prop (screw?) in contact with the water to maximize the torque transfer? Yeah I know that makes it still a hydrofoil, but if the benefits outweigh the drag??

#### jedi

##### Well-Known Member
I would think there is some kind of scale effect to consider, Perhaps hull speed versus flying speed (Sqrt Length versus area squared) if waterborne. Don't know of any similar limitations if launched over a hard surface. Is WIG lift still a direct function of Area and Velocity squared or is their a span/cord function in addition to the height ratio?

#### Starman

##### Well-Known Member
What about a WIG that keeps its propulsion prop (screw?) in contact with the water to maximize the torque transfer? Yeah I know that makes it still a hydrofoil, but if the benefits outweigh the drag??
I posted that idea here a couple of years ago, think it's good, you get more 'traction' and the prop shaft angle will help lift the vehicle out of the water if it's balanced. Something like on those longboats in Southeast Asia where they have an engine balanced/pivoting on a post on the stern and an 8-12 foot prop shaft angling down to the water, a steering handle at the front of the engine.

It would also make sure you couldn't fly out of ground effect so it would only need a boat license, then you could put a longer wing on it to get really good gas mileage.