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Old 09-17-2018, 07:02 PM   #21 (permalink)
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The Template is simply an edge case for Mair:



...a 'stretch' of zero length.

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Old 09-18-2018, 11:10 AM   #22 (permalink)
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lift

Quote:
Originally Posted by kach22i View Post
I have to give this some more thought.

I somehow believed there was a great deal of lift with the Aero-template.

The airfoil myth

The airfoil myth







I'm not sure how mainstream the blog above is, perhaps some sort of radical or heretic?
All wing sections have an angle of attack of zero lift.It is referred to as the 'bottom of the 'bucket.'' A look at Abbott and von Doenhoff's book on wing sections will illustrate it.
Half-bodies of revolution are similar to wing sections when viewed from the side,however,in no way resemble a wing in plan view (looking from the top down).There's no 'span.'
Since a streamlined body of revolution is streamlined,the rearward stagnation pressure is nearly identical to the forward stagnation pressure,with only a loss in energy,equal to what is lost with skin friction,which is the absolute minimum with the template,on account of it's specific fineness ratio.
Lift IS produced over the maximum cross-section on top,but is cancelled at the nose and tail.As long as angle of attack is not introduced.
At 135-mph,Spirit's nose produces negative 30-pounds (downforce),and the tail produces positive 22-pounds of (lift).For a 4,200-pound vehicle this lift is 'meaningless At legal speeds lift is unmeasureable.
We can't use the lift data for the baby template car due to how it was fashioned to the load cells but according to Kamm and Fachsenfeld, these half-bodies are incapable of producing lift.
Now if you get the car sideways at high speed,that's another matter all together!
I used to have graphics to share from Photobucket,but I've lost the use of all of them.
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Last edited by aerohead; 09-18-2018 at 11:13 AM.. Reason: spelling
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Old 09-18-2018, 12:45 PM   #23 (permalink)
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Quote:
Half-bodies of revolution are similar to wing sections when viewed from the side,however,in no way resemble a wing in plan view (looking from the top down).There's no 'span.'
I always think of a comparison to the wing tip, sticking out of the ground.
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Old 09-18-2018, 05:24 PM   #24 (permalink)
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Quote:
Originally Posted by aerohead View Post
Now if you get the car sideways at high speed,that's another matter all together!
Like this:



Could have been mitigated/solved with a fence or two running longitudinally over the roof, which this car did not have:

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Old 09-18-2018, 08:55 PM   #25 (permalink)
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Quote:
Originally Posted by aerohead View Post
......Half-bodies of revolution are similar to wing sections when viewed from the side,however,in no way resemble a wing in plan view (looking from the top down).There's no 'span.'
My understanding of lift from body shape partly comes from an early childhood fascination with the so-called NASA Lifting Body aircraft of the mid-1960's thru mid-1970's.

Lifting body
https://en.wikipedia.org/wiki/Lifting_body

Quote:
A lifting body is a fixed-wing aircraft or spacecraft configuration in which the body itself produces lift. In contrast to a flying wing, which is a wing with minimal or no conventional fuselage, a lifting body can be thought of as a fuselage with little or no conventional wing. Whereas a flying wing seeks to maximize cruise efficiency at subsonic speeds by eliminating non-lifting surfaces, lifting bodies generally minimize the drag and structure of a wing for subsonic, supersonic and hypersonic flight, or spacecraft re-entry. All of these flight regimes pose challenges for proper flight safety.
These "aircraft" were falling rocks (gliders) at a high angle of attack using air-ground compression to land. However the later X-24B flew at powered level flight.

technology of lifting bodies

Quote:
The X-24B is seen on the lakebed at NASA's Dryden Flight Research Centre in Edwards, California. This was the last aircraft to fly in Dryden's Lifting Body program. The final flight took place on September 2, 1975.



I'm taking Aerohead at his word, but I need time to integrate his information with other things that I'm familiar with. Being familiar may not be the same as understanding, but I'm always trying to improve.
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Old 09-22-2018, 12:24 PM   #26 (permalink)
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lifting bodies

the lifting bodies evolved from a 'nose' form with a portion slashed away in a diagonal chop,which produced delta-wing-like attached vortices for generating lift.It was discovered by accident around 1958.
They came in real 'hot',with very high stall speeds,since they didn't have a lot of wing area.
The Space Shuttle was a variation on the design,and in some landing footage,you can discern the over-wing vortices as they touch down.Landings were computer-controlled and in the event of a system failure,chase plane pilots could talk the Shuttle pilots down,as is done with the U-2 and Camaro-based spotter,so visibility wasn't as big an issue.
The Concorde utilized this also,and had to incorporate the drop-nose for takeoff and landing,as the angle-of-attack required for lift would have otherwise made visibility from the cockpit impossible.
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Old 09-22-2018, 02:47 PM   #27 (permalink)
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Quote:
They came in real 'hot',with very high stall speeds,since they didn't have a lot of wing area.
As seen in the opening scene of Six Million Dollar Man


It drops like a steerable rock.
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Old 09-23-2018, 10:09 AM   #28 (permalink)
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Quote:
Originally Posted by freebeard View Post
As seen in the opening scene of Six Million Dollar Man............

It drops like a steerable rock.
Cool, I've never seen the unique canopy in operation before.

Similar video, but with highly informative audio:


Aerohead, I've never read a description of lift before on these craft as "delta-wing-like attached vortices for generating lift". Reminds me of F-117 Nighthawk Stealth Fighter flight/lift descriptions. Thank you for the description.

These "over-wing vortices" are something I'd like to see a wind tunnel video of, I may have to look that up one day.

Such a video may answer why the early lifting bodies were upside down foil shapes, and the latter ones just the opposite with curve on top not the bottom. Part of the mystery that my brain has never been able to fully process. The key must be these over the body/wing vortices combined with the ridiculous angle of attack.

EDIT:
Freebird soundtrack, and you know this bird cannot change aaaaaaaaaa change............

At the 6:00 mark you can see the landing speed is similar to the Douglas Skyray chase plane's stall speed.



Good footage otherwise, much of it seen already in the other two videos but very crisp.
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Last edited by kach22i; 09-23-2018 at 10:26 AM..
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Old 09-23-2018, 11:21 AM   #29 (permalink)
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IIRRC, lifting bodies were more aligned with kasper theory of attached tip votrices, but could be wrong. They were attempting to make spacecraft recovery better without deploying external devices like chutes.

Also Facetmobile. https://en.m.wikipedia.org/wiki/Wainfan_Facetmobile
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Old 09-23-2018, 01:17 PM   #30 (permalink)
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[waves lighter in air]

Quote:
The M2 was a plywood aerobody built in a garage, and towed first by a car, then a C-3.
The compound curved skin should be an inspiration to ecomodders everywhere.

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