Matronics Email Lists Forum Index Matronics Email Lists
Web Forum Interface to the Matronics Email Lists
 
 Get Email Distribution Too!Get Email Distribution Too!    FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 

The Obsidian Files - A Telling Tail

 
Post new topic   Reply to topic    Matronics Email Lists Forum Index -> Europa-List
View previous topic :: View next topic  
Author Message
Area-51



Joined: 03 May 2021
Posts: 379

PostPosted: Thu May 25, 2023 6:39 pm    Post subject: The Obsidian Files - A Telling Tail Reply with quote

In this episode of the obsidian files we take a look at the empennage section of the europa and investigate ways to make it more efficient.

For this round of back yard science we have taken our pig and removed all of its apendagé but for the vertical stab... and vwalla our pig has instantly been transformed into a pug, sorry plug....

First we ran the pig (3B) head on into a 400kt stream of zero Alpha air and recorded the numbers... then we did the same with two variants, one with an added concave style empennage (Tubby Tub) and one with a more convex style empennage (3X2). The modelling on both variants was quick and crude with the sole requirement being directional signalling; better, or worse... what we ended up with was one shape similar to a Bonanza and the other a Pipistrel

Between all variants the results were not that dissimilar; so the compare & contrast aspect of this study was not remarkable.

Additional runs were also performed at 100kt.

Our meshing resolution was set to high and run through 100 solution cycles each.

Results were as follows:

Velocity 204m/s (400kt) Alpha 0 (Drag, Lift)
3B (factory) - 141kg, 2kg
TubbyTub (concave) - 149kg, 2kg
3X2 (convex) - 149kg, 11kg

At 51m/s (100kt) all pugs presented similarly at 9kg Drag and 0kg Lift.

Acoustically similar results were returned however the acoustic footprints were quite different and all becoming active aft of the fuselage max cross-section. A further journey into this phenomenon revealed boundary layer friction/cavitation as the cause for acoustic noise around the fuselage; slower air close to the surface being pulled back into free stream velocity some one inch above. As we increase velocity this acoustic noise increases in amplitude. However at 100kt this accoustic energy is only 50-60db; so we could say daytime ambient silent, i.e inaudible over the drone of nature.

So in the end the results were not greatly different to each other however out of the three little pigs the Europa's factory empennage shape came out on top on all accounts.

And a final bit of anecdotal assumption from these tests indicate 400kt Vmax with a 912 rotax at 20L/hr fuel burn is quite possible in a Europa providing the wings and horizontal stab are removed first...

This concludes this episode of the Obsidian Files and the subject open to discussion.

Europa declared "winner" again!


- The Matronics Europa-List Email Forum -
 

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?Europa-List



DA05E291-988C-4E70-AC22-5A85008ACF54.jpeg
 Description:
Factory - Acoustic - 100kt
 Filesize:  43.21 KB
 Viewed:  1383 Time(s)

DA05E291-988C-4E70-AC22-5A85008ACF54.jpeg



6CEDB21A-F2FA-490C-B787-8DBE52D162B4.jpeg
 Description:
Factory - Acoustic - 100kt
 Filesize:  54.54 KB
 Viewed:  1383 Time(s)

6CEDB21A-F2FA-490C-B787-8DBE52D162B4.jpeg



E89D5AF5-7854-4D94-BB69-864683EA9747.jpeg
 Description:
Factory - Acoustic - 100kt
 Filesize:  61.28 KB
 Viewed:  1383 Time(s)

E89D5AF5-7854-4D94-BB69-864683EA9747.jpeg



B61ABB89-B44F-460B-895E-7E5BCA549482.jpeg
 Description:
3X2 - Acoustic - 400kt
 Filesize:  61.94 KB
 Viewed:  1383 Time(s)

B61ABB89-B44F-460B-895E-7E5BCA549482.jpeg



C9491F31-814B-4B30-BBF9-57776A55E856.jpeg
 Description:
3X2 - Acoustic - 400kt
 Filesize:  63.93 KB
 Viewed:  1383 Time(s)

C9491F31-814B-4B30-BBF9-57776A55E856.jpeg



5005D0DB-E02E-4C21-AF0C-F373A692149F.jpeg
 Description:
TubbyTub - Acoustic - 400kt
 Filesize:  61.96 KB
 Viewed:  1383 Time(s)

5005D0DB-E02E-4C21-AF0C-F373A692149F.jpeg



205C9C16-3EC2-4F94-A734-E2BE0B6B534D.jpeg
 Description:
TubbyTub - Acoustic - 400kt
 Filesize:  64 KB
 Viewed:  1383 Time(s)

205C9C16-3EC2-4F94-A734-E2BE0B6B534D.jpeg



92279D85-3277-4713-8FA7-71E64EA3E344.jpeg
 Description:
Factory Acoustic - 400kt
 Filesize:  59.73 KB
 Viewed:  1383 Time(s)

92279D85-3277-4713-8FA7-71E64EA3E344.jpeg



3E9EBB74-A652-4E1E-9439-23E7CB0CAC22.jpeg
 Description:
Factory Acoustic - 400kt
 Filesize:  64.79 KB
 Viewed:  1383 Time(s)

3E9EBB74-A652-4E1E-9439-23E7CB0CAC22.jpeg



8FA9AC5B-67B1-4193-AD30-ECD1AB51E410.jpeg
 Description:
Factory - Acoustic - 400kt
 Filesize:  65.16 KB
 Viewed:  1383 Time(s)

8FA9AC5B-67B1-4193-AD30-ECD1AB51E410.jpeg



7C6FE9F2-A7A0-41C9-B3CA-DD0E7B71DA7C.jpeg
 Description:
Boundary Layer Velocity - 400kt - Cross Section
 Filesize:  49.64 KB
 Viewed:  1383 Time(s)

7C6FE9F2-A7A0-41C9-B3CA-DD0E7B71DA7C.jpeg


Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic    Matronics Email Lists Forum Index -> Europa-List All times are GMT - 8 Hours
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum


Powered by phpBB © 2001, 2005 phpBB Group