hey guys
i am currently designing an aircraft,as a part of my final year project, i am designing a ground effect vehicle, these aircraft fly at altitude of less than 50% chord length ie in this case it would be below 20 cm height, in this region their is generation of extra lift due to incomplete vortice formation and ram effect. the effective span is more than the actual span due to ground effect.so area would be more and thus wing loading would be less.
weight of aircraft: 10kg
span: 85.3cm
chord: 42.9cm
no dihedral, zero sweep and rectangular wing
i am planing to use aluminium 6061 for ribs and spars, I wanted to know
1) what should be the spacing between the ribs? will 10cm work fine?
2) what should be the thickness of the ribs? will 1/8"/ 3.175mm work fine?
3) i am planning to use a 1/4" tubular pipe with 2.235mm wall thickness for the spars, will that be ok? what should be the distance between the front and rear spar?
thanks

Very few of us here do flying models so I doubt that we can provide useful answers. Have you tried a group for radio control modellers?

I'd agree with Jessie in the main but there are a few peculiarities about this design. Firstly, the aspect ratio is very low, leading to comparatively large ribs, you were looking at 1/8 material, pretty thick for the duty, thin material, pierced and flanged would be a much more effective use of the weight, and easier the fit the skins. You don't say how thick the wing is but a normal wing would be at least 15% of chord so 6cm. I would be looking at a single full depth I section spar at about 30% of chord from the leading edge, and the leading edge forward of the spar sheeted in thin 28g sheet to form a D section. The rear spar could be a thin walled tube as you suggest. The ribs main function is to maintain the wing shape so they are usually very light, the spars carry the load. Alternatively, have a look at a design called Affordaplane, plans are on the web. The wing is very light, yet strong enough to carry a person.
Think carefully about control, your aircraft will have a maximum bank angle of 30º and a very small operating height range, it's visibility will be poor so low down, control will be very difficult.
Next, power, you don't mention it but the positioning of the thrust line could be critical, a ground effect aircraft tends to have a high thrust line to keep the prop clear of the ground, but this tends to dip the nose under power, and a power failure is an instant stall.
Finally, weight, 10Kg sounds very heavy for the wing area, design much lighter, 2 to 3Kg would be my target, but check the lift available from your wing first, you can always add payload later. Good luck.