GEM Research in the U.S. 277 
b 
[a Z ; 
#)) 
AB 
Simplified Ideal Theory: 
Equations same as for air curtain, except that power is 
furnished to only the portion (2 6) of the perimeter (27+2 6) 
Fig. 2. Air curtain with skegs 
area is 2 bh + 2 lh’ (where h’ is the clearance of the side plates above the water) as com- 
pared to AC = 2 bh + 2 lh for the simple air curtain. The simplified ideal theory performance 
is hence 
l 
Der GE 
opt AC 1+ hs 
bh 
Fe) LindetSodent obDinaed. Ix ynction 
P opt he v1 +2 1 +— pen 
The proponents of this compromise believe that the side plates, because of their low frontal 
area, can be designed to survive occasional high-speed impacts with higher-than-average 
waves. 
More detailed information on the air curtain with skegs is found in Refs. 6 and 7. 
INTEGRATED AIR CURTAIN 
The integrated air curtain provides for propulsion by directing the peripheral jet at a 
rearward-inclined angle, so that the net resultant jet reaction force is inclined forward from 
vertical. This system is illustrated in Fig. 3. Vanes in the peripheral nozzle deflect the 
jet exhaust rearward through the tangential jet deflection angle 8. If the vehicle has a 
