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Lifting body + prone position ?

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Retroflyer_S

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Effective for what?

It is absolutely dubious because (in my opinion) the true lifting body is the very least efficient aerodynamic configuration of any flying machine. The government and the military can afford to use this configuration if it were necessary, but commercial aviation and certainly private aviation cannot afford this. The lifting body was invented and tested as a way to return astronauts to the ground in an environment where wings are too easy to damage or break or burn up. But the lifting body is so inefficient that it was worth the effort to put wings on the Space Shuttle, despite having to solve the heat and structure problems.

All homebuilders are operating their aircraft where re-entry from space is not an issue (sorry Burt... almost all homebuilders). So the one and only real aerodynamic advantage of a lifting body is not present.

What we're left with that is relevant is the cost of fuel, the amount of power needed for level flight, the distance for takeoff and landing, and the amount of training necessary for the target pilot population to be competent. None of these factors favors or even tolerates the true lifting body.

The blended wing/body configuration is different, and is potntially relevant to homebuilders as Barnaby Wainfan's Facetmobile has demonstrated. But tis is nowhere near a "lifting body" like the HL-10 and M2-F2 NASA programs.

The Facetmobile proved to be far more efficient than anticipated, and there are very important advantages that this type of configuration could possibly deliver to general aviation.
Yes definitely....pure lifting body without wings is pretty much obsolete in homebuilding for sure.
 

Retroflyer_S

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DangerZone

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If I had one the landing gear would be too flimsy...

>>>

This link has been posted before. I like his prone pilot foam body mold method (could be used for conventional seats)
Interesting testing methods... :)

The guy really made an effort, but it would also help to see some old prone position testing information to skip trying to reinvent the wheel.
This is a pic from the 1940s when the Americans made some good research on the subject:
airforce.jpg

The wingsuits and wingbodies are an excellent way of flying, visibility is excellent. However, there might be some who will object about the head eing 'too exposed' or god knows what.

yves-rossy-flight.jpg

Then there was a Homo Avis some half a century or so ago...
Homo_Avis.jpg

But eventually not many went that way because flying in prone position takes some time to get used to and many ergonomic solutions to ease longer flying hours.

One thing that is sometimes problematic is pulling/pitching up suddenly because it does blurr the vision and can lead to a sudden redout. Not a good thing if you are rocketing through some trees/canyons at speeds over 200kts.
 

bmcj

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This is not aimed at you DZ... I'm just using your post as a 'jumping off' point.

Interesting testing methods... :)

The guy really made an effort, but it would also help to see some old prone position testing information to skip trying to reinvent the wheel.
This is a pic from the 1940s when the Americans made some good research on the subject:
View attachment 43516
Ouch... talk about torturing a lab rat!

DangerZone said:
The wingsuits and wingbodies are an excellent way of flying, visibility is excellent. However, there might be some who will object about the head being 'too exposed' or god knows what.

View attachment 43517
I think the only reason he gets decent forward visibility is because he flies at such a high angle of attack; if he flew flat, he would really have to bend his neck upward drastically. Just for fun, put on a motorcycle helmet, lay face down on your bed with your head and shoulders hanging over the edge, and hold you head up or level for as long as you comfortably can. I don't think it will be very long.

DangerZone said:
Then there was a Homo Avis some half a century or so ago...
View attachment 43518

But eventually not many went that way because flying in prone position takes some time to get used to and many ergonomic solutions to ease longer flying hours.
I mentioned this one before... the "Switchblade" Phasst Glider.

bondphasst1.jpg

PHASSTex.jpg

PHASSTcr.jpg
 

danmoser

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The prone position does solve some visibility issues, but this is not a profound new discovery.
.. Wright Brothers, DaVinci, Icarus, etc..
In fact, isn't EVERY flying creature found in nature a face first flier? :ponder: :gig: :ban:
 

Retroflyer_S

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Interesting testing methods... :)

The guy really made an effort, but it would also help to see some old prone position testing information to skip trying to reinvent the wheel.
This is a pic from the 1940s when the Americans made some good research on the subject:
View attachment 43516
If you push your elbows out like wings you get 20 cm ( 8 inches ) slimmer space to be at.

I recall the Luftwaffe did similar experimenting as well. Some test planes too.
 

DangerZone

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I think the only reason he gets decent forward visibility is because he flies at such a high angle of attack; if he flew flat, he would really have to bend his neck upward drastically. Just for fun, put on a motorcycle helmet, lay face down on your bed with your head and shoulders hanging over the edge, and hold you head up or level for as long as you comfortably can. I don't think it will be very long.
...
I mentioned this one before... the "Switchblade" Phasst Glider.
View attachment 43521
I have the old model of the Z1 helmet which does allow pretty good visibility skydiving at +300km/h speeds even when looking up slightly. Sure, it does require some effort and strong head/neck muscles but how long do you want to stare up into the blue sky? If longer than a (split) second, I can always fly upside down and do some backflying for a while. The motorcycle helmet is not good for testing at higher speeds, it is bulky, has a high drag and pretty circular form which is good only for hiding behind a tiny motorcycle wingshield. Enough to say that the speed with a motorcycle helmet can be below 300km/h and with the Z1 above this speed on the same R motorcycle.
z1-hp.jpg

Even when trekking without the wingsuit my body is slightly head down and still I can see other skydivers who are above my horizontal flying level. The design and aerodynamics of this helmet allows that without too much drag and so does the helmet of Ives Rossy. Thus design is crucial for someone who wants to build a high quality wingbody with good ergonomics that can enable longer flights. The second important thing is the propulsion element, its position and whether it has thrust vectoring. The Switchblade Phasst was simply badly designed and so was the Homo Volis, they had too many elementary design flaws to become successful.

Felix Baumgartner went the other way, he applied the KISS principle, Keep It Simple and St...Straight-out. He designed the Gryphon Wing with a low AR but compensated that with good flying controls. Allow to use the speed for better handling. He knew that he can't get a wingbody to fly both slow and fast without sophisticated aerodynamics knowledge so he designed the wing for high speeds and controls which can do good at velocities close to terminal. And voila, he did great, flew across The Channel. There are other wingbodies people designed, some with more success and others (majority) with less. But the basic principle still applies, if you want to fly both slow and fast (or superfast) well - the design gets complicated.

If you push your elbows out like wings you get 20 cm ( 8 inches ) slimmer space to be at.

I recall the Luftwaffe did similar experimenting as well. Some test planes too.
Indeed. But what people often neglect is the human cardiovascular system. When positioning the elbows out the proposed way - the pressure lays on the arm arteries. The circulation in the arms gets problematic even without high G loads and soon the pilot start feeling arms 'fading' and hands becoming numb. This is the least desireable effect, to enter a high G load maneouver and not have the necessary strength to get out of it due to not enough blood in the muscles. There are ergonomic solutions for this but these are details beyond the topic of the thread.
 

Retroflyer_S

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Indeed. But what people often neglect is the human cardiovascular system. When positioning the elbows out the proposed way - the pressure lays on the arm arteries. The circulation in the arms gets problematic even without high G loads and soon the pilot start feeling arms 'fading' and hands becoming numb. This is the least desireable effect, to enter a high G load maneouver and not have the necessary strength to get out of it due to not enough blood in the muscles. There are ergonomic solutions for this but these are details beyond the topic of the thread.
This has to be researched and studied.
 

DangerZone

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How do you plan on getting a test pilot?

View attachment 43536

Are you kidding..? :D

In most cases when well designed and built experimentals are in question, there are a lot of pilots who would like to try it. ;)

It's like asking how would you find guys for free testing of your pimp friend's new hooker that just turned 18 and wanted to be a porn star her whole life. Are you sure there would be no candidates to fullfill her dreams? :gig:
 
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