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ACHIEVING THE BEST REFLEXED AIRFOILS FOR FLYING WING USE IN THE SMALL PLANE CATEGORIES

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WINGITIS

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Joined
Jun 24, 2020
Messages
321
Location
Wellington, New Zealand
WHICH RAISES A POINT WORTH MENTIONING.............................................

NOTE TO ALL.....................................................AS SOME OF YOU MAY NOT KNOW.......

XFLR5 the tool we are using here has the ability to allow a manual creation of a SPLINE(Basically a 2D line around an airfoil from a picture) so that if
you folks out there have a GOOD, GREAT, RARE or even WEIRD LOOKING flying wing or reflexed airfoil please just post it as an image in the best resolution you can get it in....with a filename of what it is and what it is off.

(IT MUST BE EXACTLY AT RIGHT ANGLES AND GENERALLY NOT A PHOTOGRAPH) photographs can be done but involve a lot of time(Post processing) to get rid of parallax and sometimes even the focal length of the camera is required. I only do that for extremely RARE airfoils that no one is sure of, such as the JU52..

But for anything else I can do the rest and create a Selig format file to upload here for everyone to share in! that way you get to share in this process with us, everyone is welcome!

XFLR5 is a free tool and is fairly fully featured....it takes a while to learn.....more than just a few hours.........but have a go if you have the time.....

WARNING that may get addictive! :oops:
 

sigrana

Well-Known Member
Joined
Oct 19, 2010
Messages
59
Location
Australia
Hello folks

After starting these discussions within the thread:

Flying wing as cheap and simple option for basic fun flying

We were taking up to much space discussing Airfoils and associated things so the intention is to bring the conversation here.

I will bring across some of the topics and data we have already discussed in the next day or two.

The premise is, can we gather the best of the FW airfoils(FOR RIGID WINGS) into one place where they can be tested against a uniform set of criteria for comparison and this may drive two outcomes:

1: Others may see the FW Reflexed airfoils that are available so they may perhaps choose one that best fits their application

2: Work can be done to perhaps progress to a better generation of FW airfoils as we get into the 100 year interval since the Horten and Munk M6 type of airfoils were promulgated.....

The idea being that XFLR5(ALTHOUGH NOT PERFECT) is used as the common test tool.

NOTE: You can use PNG2PDF on their website to take XFLR5 PRTSCREENS and combine them into PDF's to provide better quality viewing on this board.

Please provide the CL, CM, CD and LD images in that order in the PDF's.

Limit the number of airfoils tested in each series to 10, it can get messy after that.....

The base settings(WE HAVE TO HAVE SOME) to test airfoils against for comparison purposes are currently:

ANALYSIS = TYPE1
MACH = 0.1
AOA = -5 to +20
RN = 3,000,000
TE = 0.2 UNLESS IT IS ALREADY LARGER (SO NO POINTY TAILS YOU CANNOT BUILD THEM ANYWAY)
NCRIT = 9
TRIP LOCATIONS = CURRENTLY UNDER DISCUSSION

For your own purposes you can use what you want but please use these settings when posting results in here.



JUST A THOUGHT, what say you?

Regards,

Kevin Gill
Wellington
New Zealand

WARNING: YOU MUST NOT USE ANY OF THESE AIRFOILS ON ANY HUMAN CARRYING AIRCRAFT WITHOUT ENGAGING APPROPRIATE DESIGNERS AND ANALYSIS TOOLS TO COMPLETELY VALIDATE REAL WORLD USAGE(THIS MEANS ALL RESPONSIBILITY AND LIABILITY IS ON YOU AS INDIVIDUALS)

The comparison of airfoils with base known ones that are well documented in previously issued NACA papers does allow for conclusions to be drawn against other airfoils created but this is an academic activity as far as this thread is concerned and airfoils should only be tested on non-human carrying models, which can be largish ones if required using the available autonomous technologies in a regulated manner taking into account the laws of your country.

For people not familiar with the Reynolds Number and how it is derived and applies to your airfoil and usage I have attached this simple self explanatory calculator:
I am adding one of my 440 wing profiles which I developed during 38 years of experimentation. Its ccharacteristics and performance are far superior to the various NACA and many others, It is ideal for flying wings.

Cordially

Bruno De Michelis

www, brunodemichelis.com
Hello folks

After starting these discussions within the thread:

Flying wing as cheap and simple option for basic fun flying

We were taking up to much space discussing Airfoils and associated things so the intention is to bring the conversation here.

I will bring across some of the topics and data we have already discussed in the next day or two.

The premise is, can we gather the best of the FW airfoils(FOR RIGID WINGS) into one place where they can be tested against a uniform set of criteria for comparison and this may drive two outcomes:

1: Others may see the FW Reflexed airfoils that are available so they may perhaps choose one that best fits their application

2: Work can be done to perhaps progress to a better generation of FW airfoils as we get into the 100 year interval since the Horten and Munk M6 type of airfoils were promulgated.....

The idea being that XFLR5(ALTHOUGH NOT PERFECT) is used as the common test tool.

NOTE: You can use PNG2PDF on their website to take XFLR5 PRTSCREENS and combine them into PDF's to provide better quality viewing on this board.

Please provide the CL, CM, CD and LD images in that order in the PDF's.

Limit the number of airfoils tested in each series to 10, it can get messy after that.....

The base settings(WE HAVE TO HAVE SOME) to test airfoils against for comparison purposes are currently:

ANALYSIS = TYPE1
MACH = 0.1
AOA = -5 to +20
RN = 3,000,000
TE = 0.2 UNLESS IT IS ALREADY LARGER (SO NO POINTY TAILS YOU CANNOT BUILD THEM ANYWAY)
NCRIT = 9
TRIP LOCATIONS = CURRENTLY UNDER DISCUSSION

For your own purposes you can use what you want but please use these settings when posting results in here.



JUST A THOUGHT, what say you?

Regards,

Kevin Gill
Wellington
New Zealand

WARNING: YOU MUST NOT USE ANY OF THESE AIRFOILS ON ANY HUMAN CARRYING AIRCRAFT WITHOUT ENGAGING APPROPRIATE DESIGNERS AND ANALYSIS TOOLS TO COMPLETELY VALIDATE REAL WORLD USAGE(THIS MEANS ALL RESPONSIBILITY AND LIABILITY IS ON YOU AS INDIVIDUALS)

The comparison of airfoils with base known ones that are well documented in previously issued NACA papers does allow for conclusions to be drawn against other airfoils created but this is an academic activity as far as this thread is concerned and airfoils should only be tested on non-human carrying models, which can be largish ones if required using the available autonomous technologies in a regulated manner taking into account the laws of your country.

For people not familiar with the Reynolds Number and how it is derived and applies to your airfoil and usage I have attached this simple self explanatory calculator:
I am attaching one of my 440 plus airfoils which I have developed in 38 years of activity. This one is particularly indicated for flying wing aircraft.

Stable high performance profile.jpg
 

WINGITIS

Well-Known Member
Joined
Jun 24, 2020
Messages
321
Location
Wellington, New Zealand
I am adding one of my 440 wing profiles which I developed during 38 years of experimentation. Its ccharacteristics and performance are far superior to the various NACA and many others, It is ideal for flying wings.

Cordially

Bruno De Michelis

www, brunodemichelis.com


I am attaching one of my 440 plus airfoils which I have developed in 38 years of activity. This one is particularly indicated for flying wing aircraft.

View attachment 100802
Hello Bruno

Welcome to the thread, thank-you very much for posting an airfoil.

That airfoil looks very interesting indeed and so does your website:


You may have noticed that when posting images on this board the quality is reduced, this has happened to that airfoil image you posted, we normally put them on here as PDF's so the quality can be retained.

I use Convert PNG Images to PDF Documents Online to convert images to PDF's, it is a free site.

We analyze at RE/RN=3,000,000 and it looks like your airfoil will have an even higher CL if you test it at that.

Regards
Kevin
 

WINGITIS

Well-Known Member
Joined
Jun 24, 2020
Messages
321
Location
Wellington, New Zealand
Hello Bruno

Welcome to the thread, thank-you very much for posting an airfoil.

That airfoil looks very interesting indeed and so does your website:


You may have noticed that when posting images on this board the quality is reduced, this has happened to that airfoil image you posted, we normally put them on here as PDF's so the quality can be retained.

I use Convert PNG Images to PDF Documents Online to convert images to PDF's, it is a free site.

We analyze at RE/RN=3,000,000 and it looks like your airfoil will have an even higher CL if you test it at that.

Regards
Kevin
I quite like the EKRANOLET!
 

Norman

Well-Known Member
HBA Supporter
Joined
Nov 28, 2003
Messages
3,044
Location
Grand Junction, Colorado
Its not to far of yours in terms of results, less lift but more CM.

But yours is 2% thicker so that's a lot of difference!
That's why it says "mod of M-35a" in the file name. I don't know how I failed to see the original in my database. I have a project file with all the airfoils Marske has mentioned using that aren't proprietary. One of the files I have of attempted recoveries of the Go765 matches yours perfectly down to the number of points. The spline I posted is a tracing of a set of coordinates labeled "attempt 5" which was the least lumpy of the measurements of a museum Me163 that was posted on Rob de Bie's Me163 site many years ago . The slope and radius info looks like it accounts for most of the difference and may be from a different spanwise position.
 

Norman

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HBA Supporter
Joined
Nov 28, 2003
Messages
3,044
Location
Grand Junction, Colorado
Now that my memory has been jogged I know where I got the M-35a data. Jim Marske finaly got around to writing a real book and self published it this year. One of the appendices is a list of airfoils he has used and their coordinates. That's where I got the M-35a. I finished typing them in about 20 minutes before a facebook friend offered me a .DAT file. Your tracing is very good. If you'd like to compare it to Marske's published coords here they are.

M-35a-NM mod-comp.png
 

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Riggerrob

Well-Known Member
Joined
Sep 9, 2014
Messages
1,545
Location
Canada
Hello Iwerk

Yes well, a constantly changing airfoil would be hard to model accurately in the software!

The concept is rather scary..........still having to do a forced landing in water would be ok..
If you keep the chord long and Reynolds number high and airspeeds slow (ala. Facetmobile) minor flexing makes little difference to the airfoil. My experience comes from 6,000 on ram-air parachutes. Mind you, parachutes enjoy pendulum stability.
 

WINGITIS

Well-Known Member
Joined
Jun 24, 2020
Messages
321
Location
Wellington, New Zealand
That's why it says "mod of M-35a" in the file name. I don't know how I failed to see the original in my database. I have a project file with all the airfoils Marske has mentioned using that aren't proprietary. One of the files I have of attempted recoveries of the Go765 matches yours perfectly down to the number of points. The spline I posted is a tracing of a set of coordinates labeled "attempt 5" which was the least lumpy of the measurements of a museum Me163 that was posted on Rob de Bie's Me163 site many years ago . The slope and radius info looks like it accounts for most of the difference and may be from a different spanwise position.
Yes I agree a span-wise twist would account for it.

Cheers
 

WINGITIS

Well-Known Member
Joined
Jun 24, 2020
Messages
321
Location
Wellington, New Zealand
Now that my memory has been jogged I know where I got the M-35a data. Jim Marske finaly got around to writing a real book and self published it this year. One of the appendices is a list of airfoils he has used and their coordinates. That's where I got the M-35a. I finished typing them in about 20 minutes before a facebook friend offered me a .DAT file. Your tracing is very good. If you'd like to compare it to Marske's published coords here they are.

View attachment 100811
Thanks Norman

I have just set them to the XFLR5 0.2TE setting and compared them and they are indeed pretty close...

That is encouraging, because I do spend a fair bit of effort on some of those splines!

Here is the Comparo..
 

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