Lift on aircraft wing
Discussion
It's something to do with them having a rigid or semi rigid rotor head, so maybe it's a fairly standard Westland thing? apache was built under licence though so presumably has whatever Boeing usually use.
Heicopters really are a dark art though, they don't actually fly, they just beat the air in to submission.
Heicopters really are a dark art though, they don't actually fly, they just beat the air in to submission.
couple of other questions not techy
The idiots view is that total psi under the wing minus total psi above the wing ,should be near to the weight of the aircraft giving assistance to it taking off
Looking at a couple of fighters ,the EE Lighting and the Lockheed F104 brought up this in my head
One the Lightning does the aerofoil shape keep parallel to the fuselage or keep at 90 degrees to the leading edge
Hope that makes sense
And how did the F104 manage with such small wings, bearing in mind the idiots guide above
I realise it was named to coffin maker, but i thought that was because the German airforce lost a lot of the type
The idiots view is that total psi under the wing minus total psi above the wing ,should be near to the weight of the aircraft giving assistance to it taking off
Looking at a couple of fighters ,the EE Lighting and the Lockheed F104 brought up this in my head
One the Lightning does the aerofoil shape keep parallel to the fuselage or keep at 90 degrees to the leading edge
Hope that makes sense
And how did the F104 manage with such small wings, bearing in mind the idiots guide above
I realise it was named to coffin maker, but i thought that was because the German airforce lost a lot of the type
The F104 had to go very fast to maintain enough lift. for low speed flight it used "blown flaps" where it blew air out of vents in the wing to increase the effective camber of the wing. This meant that they lost the engine the stall speed was so high that that were supposed to eject rather than try to glide land. Even with the flaps the landing speed was 175kts, so dread to think what it would have been without an engine.
For comparison, landing speed for a Lightning was 130kts.
For comparison, landing speed for a Lightning was 130kts.
silverfoxcc said:
couple of other questions not techy
The idiots view is that total psi under the wing minus total psi above the wing ,should be near to the weight of the aircraft giving assistance to it taking off
Looking at a couple of fighters ,the EE Lighting and the Lockheed F104 brought up this in my head
One the Lightning does the aerofoil shape keep parallel to the fuselage or keep at 90 degrees to the leading edge
Hope that makes sense
And how did the F104 manage with such small wings, bearing in mind the idiots guide above
I realise it was named to coffin maker, but i thought that was because the German airforce lost a lot of the type
well for takeoff you want a pressure differential. at level flight lift is equal to weight. The idiots view is that total psi under the wing minus total psi above the wing ,should be near to the weight of the aircraft giving assistance to it taking off
Looking at a couple of fighters ,the EE Lighting and the Lockheed F104 brought up this in my head
One the Lightning does the aerofoil shape keep parallel to the fuselage or keep at 90 degrees to the leading edge
Hope that makes sense
And how did the F104 manage with such small wings, bearing in mind the idiots guide above
I realise it was named to coffin maker, but i thought that was because the German airforce lost a lot of the type
you can cut a wing in any direction and see an aerofoil section, it will just be different depending on the line you cut. the design aerofoil will be in the direction of the airflow [so oriented with fuselage as per your question] which will differ depending on the sweep angle of the wing. so unswept the design aim would be for lift and low speed maneuvering, swept would be to minimise wave drag at transonic / supersonic speed.
the f104 is very light, max take off weight around 14ton, and had very high take off / landing speeds. lift is proportional to velocity. both those aircraft would glide like a brick if the engine was cut.
silverfoxcc said:
couple of other questions not techy
The idiots view is that total psi under the wing minus total psi above the wing ,should be near to the weight of the aircraft giving assistance to it taking off
Looking at a couple of fighters ,the EE Lighting and the Lockheed F104 brought up this in my head
One the Lightning does the aerofoil shape keep parallel to the fuselage or keep at 90 degrees to the leading edge
Hope that makes sense
And how did the F104 manage with such small wings, bearing in mind the idiots guide above
I realise it was named to coffin maker, but i thought that was because the German airforce lost a lot of the type
The Lightning would have the section parallel to the fuselage.The idiots view is that total psi under the wing minus total psi above the wing ,should be near to the weight of the aircraft giving assistance to it taking off
Looking at a couple of fighters ,the EE Lighting and the Lockheed F104 brought up this in my head
One the Lightning does the aerofoil shape keep parallel to the fuselage or keep at 90 degrees to the leading edge
Hope that makes sense
And how did the F104 manage with such small wings, bearing in mind the idiots guide above
I realise it was named to coffin maker, but i thought that was because the German airforce lost a lot of the type
The F-104 had a high wing loading, which wasn’t much of an issue for its intended role. For lower speeds it had an ingenious ‘blown flap’ system, whereby as the flaps were lowered, they exposed slots in the hinge which blew high pressure air from the engine over them to increase lift. Of course engine failure would be a big issue when, for example, landing.
ETA - Apologies, I didn't see RTR's response before posting mine saying the same thing.
Edited by dr_gn on Tuesday 28th March 12:51
silverfoxcc said:
couple of other questions not techy
The idiots view is that total psi under the wing minus total psi above the wing ,should be near to the weight of the aircraft giving assistance to it taking off
The idiots view is that total psi under the wing minus total psi above the wing ,should be near to the weight of the aircraft giving assistance to it taking off
To take off, psi under wing minus psi above the wing needs to be greater than weight. Its not just "assistance", its the only thing lifting the aircraft.
On cruise, it needs to be equal (simplification neglecting the effect of tail, fuselage, thrust direction etc.)
silverfoxcc said:
And how did the F104 manage with such small wings
Wing loading comes into it. Simplistic assumption, for a given wrong profile lift varies linearly with angle of attack (AKA alpha) up to about 15 degrees.
You could design your aircraft to cruise at 1 degree alpha, with the wing producing 1g worth of lift. If you then increased alpha to 15 degree, it would produce 15g. It would be a very big wing, with lots of friction drag. You could call it a fighter wing.
You could alternatively design it to cruise at 3 degree alpha, again producing 1g of lift. If you increased the alpha to 15 degree, it would only produce 5g, but the wing would be smaller (1/3 of the size!) with less friction drag. You could call it an interceptor wing.
As you slow down from cruise, lift drops with speed squared. So an interceptor wing which produces 1g at say 400knots with 3 degrees alpha, would only produce 0.25g at 200 knots. So you need to increase alpha to 12 degrees. As you slow down further, you can't sustain level flight with that wing. Hence lift improvements devices for low speed.
dr_gn said:
silverfoxcc said:
couple of other questions not techy
The idiots view is that total psi under the wing minus total psi above the wing ,should be near to the weight of the aircraft giving assistance to it taking off
Looking at a couple of fighters ,the EE Lighting and the Lockheed F104 brought up this in my head
One the Lightning does the aerofoil shape keep parallel to the fuselage or keep at 90 degrees to the leading edge
Hope that makes sense
And how did the F104 manage with such small wings, bearing in mind the idiots guide above
I realise it was named to coffin maker, but i thought that was because the German airforce lost a lot of the type
The Lightning would have the section parallel to the fuselage.The idiots view is that total psi under the wing minus total psi above the wing ,should be near to the weight of the aircraft giving assistance to it taking off
Looking at a couple of fighters ,the EE Lighting and the Lockheed F104 brought up this in my head
One the Lightning does the aerofoil shape keep parallel to the fuselage or keep at 90 degrees to the leading edge
Hope that makes sense
And how did the F104 manage with such small wings, bearing in mind the idiots guide above
I realise it was named to coffin maker, but i thought that was because the German airforce lost a lot of the type
Yertis said:
One of the things that has interested me about aerofoils, since I was kid making actually, is how the aerofoil presented to the airflow changes on swing-wing aircraft. As the wings swing back the aerofoil as presented to the air changes completely. So there must be some quite interesting maths going on to ensure that the aerofoil is optimised as far as possible for all sweep angles. Or is it optimised for one sweep angle, and a compromise accepted at other angles? Also, does the angle of incidence change according angle of sweep?
At high speed a thin aerofoil is more efficient than a thick one. At low speed a thick or heavily cambered one is more effective. A swept wing allows a deeper spar in a wing of the same wing section. One of the benefits of a swing wing is that it allows a less cambered low aspect ratio wing at high speed and a more cambered higher aspect ratio wing at low speed. A swing wing's section will no doubt be a compromise at either speed range but still more efficient than a fixed wing overall. There probably will be a reduction in incidence when swinging the wing, as the chord increases and the effective depth reduces, however most swing wing aircraft have all moving tails which allow the longitudinal dihedral (difference in incidence between the wing and tail) to be optimised.
Leaving aside leading and trailing edge devices (slats and flaps) the only swing wing that I am aware of that could adjust its wing incidence was Barnes Wallis's Wild Goose unmanned test aircraft which also used differential incidence and sweep for roll control (seen here on its launch trolley at Predannack, Cornwall between 1950 & 1952).
Edited by GliderRider on Wednesday 29th March 18:18
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