Hurricane - glide rate

[waroff]

Read in AP1564A Hurricane I- Merlin II
"Gliding.
With flaps and undercarriage down a good average gliding speed is 80 m.p.h. A.S.I. reading with the engine running slightly faster than idling speed.

Approach
The normal method of approaching to land is by means of straight glide(at the speed mentioned above)

If for any reason a landing is being made with the flaps up increase the approach speed by 10 m.p.h. A.S.I. reading."

[Christer Engdahl]

Originally Posted by Revi16

It just ends up being whatever it is after the other performance goals are met.

Exactly what I meant, when the goal of low drag is met, you get a good glide ratio in the bargain! Compare the P-51. A "laminar flow profile" was developed to get the lowest possible drag and I bet it had one of the best glide ratios but at a comparatively high speed.

[Graham Boak]

The Mustang has less zero-lift drag, although most of its benefit was due to the flow through the radiator which would no longer help as much, but being heavier requires more lift, and hence more lift-induced drag. A simple taper wing is less efficient (if not a lot) than an elliptically-loaded wing like the Spitfire or Hurricane (with a straight centre section and tapered outer panels which comes close to the loading obtained from an elliptically-shaped wing). It is not obvious to me that the Mustang would have less overall drag, perhaps even the contrary. It will not be able to maintain a high speed without sticking its nose down and losing height, which rather defeats the point.

It seems to me that whichever aircraft you choose will attain its best glide rate from flying at its maximum L/D, which for a Bf109 is around 7. (I remember this from some Breguet Range Equation calculations demonstrating that some of the proposed range performance figures for the He100 were grossly optimistic nonsense.) I suspect (but cannot confirm) that this would be close to its optimum cruise/endurance speed. I don't know what the peak L/D is for these other types, nor how to get to the glide rate from this. Mea culpa.

[RSwank]

There is an interesting multipart article on learning to fly a Mustang here:

http://www.airbum.com/pireps/PirepMustangBurch.html

The author takes a "warbird" training course in Texas to learn how to fly WWII planes.

In part 7: http://www.airbum.com/pireps/PirepMustangBurch.7.html
the author mentions the glide ratio of the Mustang.

"I was at 6,000 feet and I thought I'd never get that thing down from altitude. At 175 mph it has a glide ratio of nearly 15:1; it will glide three miles for every thousand feet of altitude."

Another interesting comment:

"The Mustang was built to be flown by well-trained 200-hour pilots. I repeat, well trained, and if a pilot gets that same sort of training, the Mustang will be a piece of cake. On the other hand, if you approach the Mustang figuring you can whip it because you have thousands of hours in Bonanzas and the like, it'll chase you all over the airport. The P-51 has characteristics that nothing in civilian aviation can prepare you for."

[Revi16]

Originally Posted by Christer Engdahl

Exactly what I meant, when the goal of low drag is met, you get a good glide ratio in the bargain! Compare the P-51. A "laminar flow profile" was developed to get the lowest possible drag and I bet it had one of the best glide ratios but at a comparatively high speed.

My initial post which you quoted was "Best glide rate wasn't high on the performance needs list" only meant that a specific glide ratio wasn't a target goal in the development of fighters. The performance goals were Speed, Climb Rate, Altitude and Range.

The Spitfire Mk. I had a much lighter wing loading (and better glide ratio) than the later developed Spitfire Mk.'s. While the later Mk.'s "Power On" performance numbers kept increasing, their glide ratios decreased.


Edit - as for the other posts referencing "glide ratios", there is a distinct difference between a fully functional aircraft with its engine at idle (still making power) and an inoperable engine. An inoperable engine with the prop still turning is a huge air brake, the glide ratio will suffer greatly.