Laminar flow wings

http://www.daviddarling.info/encyclopedia/L/laminar_flow.html

Now can someone post on the other types used in the war?

Here's a thread on the subject

http://forums.ubi.com/eve/ubb.x?m=441100584&a=tpc&s=400102&f=23110283

Laminar flow was great for fighters with high power:weight ratios as it allows for even less induced drag. But less induced drag also means much less lift, basically at high speeds its great, but low speeds = ****. The stall speed is much higher, wing loading is ussually lower. Also the wings aren't as thick so there is less room for fuel too.


The B-24 bomber's "Davis" airfoil was also a laminar flow airfoil, which predates the Mustang's. However, the designers of the B-24 only knew that their airfoil had very low drag in the wind tunnel. They did not know that it was a laminar flow airfoil.

There were several aircraft modified by NACA, in the late 1930s, to have laminar flow test sections on their wings. Hence, such aircraft as a modified B-18 were some of the first aircraft to fly with laminar flow airfoils.

The boundary layer concept is credited to the great German aerodynamicist, Ludwig Prandtl. Prandtl hyposthesized and proved the existence of the boundary layer long before the Mustang was a gleam in anyone's eye.


The P-51 Mustang is the first aircraft every intentionally designed to use laminar flow airfoils. However, wartime NACA research data I have shows that Mustangs were not manufactured with a sufficient degree of surface quality to maintain much laminar flow on the wing. The RAE found that the P-63, despite being designed with laminar airfoils, also was not manufactured with sufficient surface quality to have much laminar flow

Spiteful had em & wasn't considered success.

Anyway, be interesting to have conventional & trapezoidal? site brought in to compare all 3.

 

Spit & 47 were elliptical.

http://en.wikipedia.org/wiki/Elliptical_wing

 

Well, looks like everyone's exited about this one.

I'll say this, doesn't seem as though there was a perfect wing design for fighters, laminar good for speed, elliptical good for turn? Though 47 had one & wasn'r near as good in turn as Spit.

Tempest seemed to combine 2 designs into one. Laminar, but also looked elliptical like Spit. Lamaliptical perhaps.

 

I think you are mixing up two entirely different subjects. I never saw any reference to the wing planform being elliptical, trapezoidal, rectangular, whatever to the benefits gained by the airfoil being laminar or not.

The early Spitfires, with the beautiful elliptical wings, had a plain old Clark Y wing section.

 

Tempest wing was similiar in shape to the Spit, but was also laminar flow.

http://en.wikipedia.org/wiki/Hawker_Tempest

The laminar flow wing had a maximum chord, or ratio of thickness to length of the wing cross section, of 14.5 %, in comparison to 18 % for the Typhoon. The maximum thickness was further back towards the middle of the chord. The new wing was originally longer than that of the Typhoon at 43 ft (13.1 m), but the wingtips were clipped and the wing became shorter than that of the Typhoon at 41 ft (12.5 m).

The new wing cramped the fit of the four Hispano 20 mm cannon that were being designed into the Typhoon. They had to be moved back further into the wing, and the wing was extended into an elliptical shape

No confusion.

 

No?. Then go back to Wikipedia and look up "laminar flow wing sections", and find out if there is any relation between a wing section (laminar or turbulent flow) and the wingplan.

 

Both are part of the wing design, so yes they are related.

 

Sorry, no. Wing planform and wing section have nothing to do with each other, you can pick up a ruler and a triangle set and design a wing planform to any shape you like, and then use any wing section you wish from a list. For instance Dr. Mike Selig (Univ. Indiana, http://www.ae.uiuc.edu/m-selig/ads.html) has a list of more than 1500 sections to chose from. Or you can pick a decent software like www.profili2.com and play with it till you get fed up.

As I said above, the early Spitfires had that beautiful wing planform but a primitive wing section that nowadays is no longer used not even in the most basic airmodels.

At most, for a laminar wing section (and what is a laminar wing section? a wing section where turbulent flow inception - also called boundary layer separation - is delayed further along the chord than usual) to work better, it should have no kinks on the planform, that is a pure elliptic or a pure trapezoid or rectangle.

Pure elliptic: Spitfire.
Pure trapezoid : P-51, Me-109, FW190, Hellcat, etc.

Of the above, to my knowledge only the P-51 carried a laminar flow wing section, develop in the NACA labs (National Advisory Commitee for Aeronautics), later NASA.

On a 'cranky' wing like an Avenger a laminar flow wing section would lose efficiency at least in the mid wing kink neighbourhood due to mutual interference.

To further add to confusion, normally a wing does not have a constant wing section, the section from root to tip will vary more or less smoothly providing different lift and drag coefficients along the wingspan as well as varying stall behaviour. This is called areodynamic torsion, as opposed to geometric torsion, whereby the wing section is constant but twisted a few degrees nose downwards towards the tip. Aerodynamical and geometric torsion can and are often combined.

But of course you know all about this already.

 

Sorry yes. Wing planform & wing section are both components of wing design, therefore related. & Tempest had shape similiar to Spit, hence elliptical, & as well had laminar flow added to the design of its wing.


"Of the above, to my knowledge only the P-51 carried a laminar flow wing section, develop in the NACA labs (National Advisory Commitee for Aeronautics), later NASA."


Tempest & P-63 also had laminar.

 

Ok, I see now. Another

 

The shape of a wing greatly influences the performance of an airplane. The speed of an airplane, its maneuverability and its handling qualities are all very dependent on the shape of the wings.

http://virtualskies.arc.nasa.gov/aeronautics/tutorial/wings2.html

So the shape & planform both are related to how well the wing cuts through the air.

 

Spit, 109, & Stang

While Spitfire had the much vaunted elliptical wing (effect of which is much debated), the P-51 had its (again , much debated) laminar flow wing (trapeze in this case)


The wing of the 109 was made with no warp from tip to root (same angle all the way), this made it very efficient liftwise compared to "Allied wings", which had up to 2 degrees of washout to avoid tip stalling of the wing. Messerschmitt solved the same problem by adding excellent (British licensed, Handle Page invented) automatic slats to extend when the tip would stall. This made the 109 almost impossible to spin.

At the end of the day, it is how well the wing will roll, turn, perform in dive etc that matters.

Stang did most of these things well. Spit didn't roll & dive well, ( MK 14 excepted ), & 109 wing was a bit small & in the case of the G-6 had to flown at high speed at high altitude cause wings didn't get enough air purchase.

Comparing these 3 different design philosophies & the various pros & cons thereof was where I was attempting to go with the post.