1 Field of the Invention
In aerospace industry, demand for the high performance airfoil in terms of higher lift coefficient, lower drag coefficient is always in demand. With the higher lift capable airfoil, the wings and control surfaces size can be reduced significantly and subsequently the weight reduction too. In this view an attempt is made to enhance the existing airfoil performance by manipulating the effective camber through the controlled manipulation of the trailing edge thickness of an existing airfoil. This particular invention best suits for helicopter stabilizers though it can be used for various other high lifting applications.
2 Description of the Invention
Trailing edge thickness in terms airfoil chord length is increased from 1.4% to 7.0% and studied for lift coefficient and drag coefficient. Both CL and CD increase as the trailing edge thickness increases. State-of-art CFD package has been used for assessing the airfoil aerodynamic characteristics (CL & Co). Trailing edge thickness of 2.1% enhances the Yift coefficient by 26.8% with a marginal drag penalty at 0° angle of attack. Subsequently, at all other angles of attack substantial lift increase is observed with marginal drag penalty. Over all, the absolute lift increase is significant though there is some drag penalty. The drag increase compared with gurney flap method and is found much lesser in case of trail edge thickness increase.
However, marginal drag increase of helicopter stabilizers can be compromised over their substantial lift benefits. On the other hand, the drag increase of the empennage influences the tail boom shake phenomenon positively. Over all the manipulation of the effective camber through the systematic modification of the trailing edge thickness of an existing airfoil is successfully carried out to enhance the lift of the airfoil and subsequently the wing.
Over all the trailing edge thickness increases as proposed enhances the wing lifting characteristics significantly across a wide range of angles of attack though lift to drag ratio got effected mildly. However, a wing with proposed trailing edge modifications produces several positive effects for helicopter vertical fin applications over the existing wing that is in use. Another advantage of trailing edge thickness increase enables designer to choose more spar height to get good strength wing in view of berating loads.
3 Use of the Invention
Enhanced airfoil can be used for vertical fin and horizontal stabilizer applications of helicopter through which area reduction, weight reduction and ease of construction can be achieved. However, present invention can be used for any other high lifting wing requirements also for other relevant applications.

4 Aim of the Invention
Present invention of airfoil trailing edge thickness manipulation .enables the designers to achieve enhanced high lifting wings in terms of desired wing size reduction significantly along with the substantial weight reduction. On the other this invention improves the helicopter vertical fin structural design which allows to use the trailing edge spar.
5 Prior art Comparison
Gurney flap is the classical and proven method for enhancing the existing wings lift significantly. Various features of the gurney flaps are as follows;
• Significant lift increment can be achieved with the gurney fl^ps.
• Drag increase is notably higher with the gurney flaps, but the strong need of the higher lift motivates one to use the gurney flaps.
• On the other hand, gurney flaps installation needs additional structural features and it will not improve the structural strength of the existing wings.
• Further,, mild unsteady effects would be introduced with th^gurney flaps.
• Best of the gurney flap design is that it is a retrofit-able device.
Present invention is not a retrofit-able device and this feature must be incorporated in the basic design of the wing. However it possess a few good features as follows;
• Significant lift increment can be achieved with the trailing edge manipulation proposed in this manuscript.
• Drag increase is lesser than the drag increase with gurney fla.pS,
' • Trailing edge thickness increase helps to introduce a 'C channel spar at the trailing and hence structural strength increases.
• Unsteady aerodynamics is less.
• It is not a retrofit-able feature.
• Increased trailing edge thickness can be used for running loQms 0r so if required.
6 Brief description of Drawings
Trailing edge thickness increase on pressure side of airfoil from 1.4% to 7.0% in steps of 1.4% is depicted in Figure 1(a). Figure 1(b) shows the detailed view of the trailing eyge. Lift coefficient. Drag coefficient and Lift to Drag Ratio of the baseline and modified airfoil are shown jn Figure 2, Figure 3 and Figure 4 respectively. A wing with the proposed trailing edge manipulation is modelled and estimated the lift and drag along with baseline wing. Figure 5 and Figure 6 shows the wing |jft and drag details respectively.

Claims of the present Invention
. 1. Trailing edge cusping and thickness increase to 1.4% to 4.2% in terms of airfoil chord length on the pressure side to augment the lift coefficient and/or absolute lift of an airfoil or wing while maintaining the baseline drag coefficient and/or absolute drag identical or with a marginal increase.
2. Modification of an airfoil trailing edge thickness as said in claim 1, to augment/increase lift coefficient of an airfoil and/or absolute lift of a wing.
3. Modification of the airfoil trailing edge thickness as said in claim 1, to reduce the size of aerodynamic surface(s) like lifting wings, horizontal stabilizers, flaps, ailerons, vertical fins and rudders.
4. Modification of an airfoil trailing edge thickness as said in claim 1 and claim 3, to reduce the weight of the aerodynamic surface(s) like lifting wings, horizontal stabilizers, flaps, ailerons, vertical fins and rudders.
5. Modification of an airfoil trailing edge thickness as said in claim 1, to reduce the overall
' aircraft/helicopter weight by means of aerodynamic surface(s) size reduction.
6. A wing constructed with modification of an airfoil trailing edge thickness as said in ctoim I, to accommodate any routings/systems that are mechanical or hydraulic or pneumatic or electrical or altogether.
7. Modification of the airfoil trailing edge thickness as said in claim 1, thickness control of the wing through electrical, mechanical, pneumatic and hydraulic systems in combination or alone.
8. A wing with trailing edge modified airfoil as said in claim 1, using as a helicopter horizontal stabilizer that submerged in to the main rotor downwash.
9. Modification of the airfoil trailing edge thickness as said in claim 1, to enhance trailing edge spar height for the structural construction.
10. Modification of the airfoil trailing edge thickness as said in claim 1, to reduce the flow separation over the vertical fin trailing edge to improve the tail rotor efficiency.