Ye Olde Rocket Forum

Go Back   Ye Olde Rocket Forum > BARCLONE > Designer's Studio
User Name
Password
Auctions Register FAQ Members List Calendar Today's Posts Search Mark Forums Read


Reply
 
Thread Tools Search this Thread Display Modes
  #1  
Old 03-13-2010, 06:48 PM
CPMcGraw's Avatar
CPMcGraw CPMcGraw is offline
BARCLONE Rocketry
 
Join Date: Mar 2005
Location: Mobile, Alabama
Posts: 5,355
Exclamation New Design -- Freewind BG

Here's a glider design that I'm trying to morph into a pop-pod BG. The glider should fly as shown, with the CG at about 25%. The ballast weight is about 1/8th ounce, or one good ball-shaped fishing sinker. I'm going to build a couple of these to see if I can trim it for a good glide, then I'll work on the pod.

Notice on the 2D views the working margin value of 8769.28... RockSim says it's overstable.

Wingspan: 13.5"
Length: 12"
Weight: 0.472 oz

Enjoy!
Attached Thumbnails
Click image for larger version

Name:  Freewind BG 2D Base View.jpg
Views: 94
Size:  80.3 KB  Click image for larger version

Name:  Freewind BG 2D Side View.jpg
Views: 98
Size:  79.3 KB  Click image for larger version

Name:  Freewind BG 3D.jpg
Views: 112
Size:  28.8 KB  
Attached Files
File Type: rkt Freewind BG.rkt (34.7 KB, 90 views)
__________________
Craig McGraw

BARCLONE Rocketry -- http://barclone.rocketshoppe.com
BARCLONE Blogsite -- http://barclone.wordpress.com
BARCLONE Forum -- BARCLONE Forum

BARs helping BARs

SAM 0044
AMA 352635
Reply With Quote
  #2  
Old 03-13-2010, 09:02 PM
JRThro's Avatar
JRThro JRThro is offline
BAR Wannabee
 
Join Date: Mar 2005
Location: NW Houston, TX
Posts: 1,304
Send a message via MSN to JRThro Send a message via Yahoo to JRThro
Default

I really like the look of this one, Craig.
__________________
John Thro, NAR #84553 SR
I was too old when I started! Now I'll *never* become a BAR!
Reply With Quote
  #3  
Old 03-13-2010, 09:14 PM
CPMcGraw's Avatar
CPMcGraw CPMcGraw is offline
BARCLONE Rocketry
 
Join Date: Mar 2005
Location: Mobile, Alabama
Posts: 5,355
Default

Quote:
Originally Posted by JRThro
I really like the look of this one, Craig.


Thanks!

I wish I knew more about BGs than I do. There's both an art and a science to them, unfortunately I'm neither an artist nor a scientist...
__________________
Craig McGraw

BARCLONE Rocketry -- http://barclone.rocketshoppe.com
BARCLONE Blogsite -- http://barclone.wordpress.com
BARCLONE Forum -- BARCLONE Forum

BARs helping BARs

SAM 0044
AMA 352635
Reply With Quote
  #4  
Old 03-14-2010, 12:40 PM
JRThro's Avatar
JRThro JRThro is offline
BAR Wannabee
 
Join Date: Mar 2005
Location: NW Houston, TX
Posts: 1,304
Send a message via MSN to JRThro Send a message via Yahoo to JRThro
Default

Quote:
Originally Posted by CPMcGraw
Thanks!

I wish I knew more about BGs than I do. There's both an art and a science to them, unfortunately I'm neither an artist nor a scientist...

Yeah, you and me both. And I don't generally have either the time or the inclination to spend much time trying to refine things until they work right.
__________________
John Thro, NAR #84553 SR
I was too old when I started! Now I'll *never* become a BAR!
Reply With Quote
  #5  
Old 03-14-2010, 09:33 PM
kevinj kevinj is offline
Not so Junior
 
Join Date: Apr 2009
Posts: 381
Default

The one rule of thumb that I've always used is to have some stability inducing part of the glider be on both sides of the motor thrust line. I've done this by having the vertical stab under the fuse and the wingtips above the thrust line via dihedral. That said, I do like the looks of the glider.
Reply With Quote
  #6  
Old 03-14-2010, 10:55 PM
CPMcGraw's Avatar
CPMcGraw CPMcGraw is offline
BARCLONE Rocketry
 
Join Date: Mar 2005
Location: Mobile, Alabama
Posts: 5,355
Exclamation

Quote:
Originally Posted by kevinj
The one rule of thumb that I've always used is to have some stability inducing part of the glider be on both sides of the motor thrust line. I've done this by having the vertical stab under the fuse and the wingtips above the thrust line via dihedral. That said, I do like the looks of the glider.


Kevin,

Behold... The Freewind BG Mk II...

Is this something of what you had in mind? I know the wing tips are not quite where you're describing, but I may have another idea for that...
Attached Thumbnails
Click image for larger version

Name:  Freewind BG Mk II 3D.jpg
Views: 83
Size:  33.0 KB  Click image for larger version

Name:  Freewind BG Mk II 2D Side View.jpg
Views: 73
Size:  78.9 KB  Click image for larger version

Name:  Freewind BG Mk II 2D Base View.jpg
Views: 80
Size:  79.8 KB  
Attached Files
File Type: rkt Freewind BG Mk II.rkt (39.2 KB, 71 views)
__________________
Craig McGraw

BARCLONE Rocketry -- http://barclone.rocketshoppe.com
BARCLONE Blogsite -- http://barclone.wordpress.com
BARCLONE Forum -- BARCLONE Forum

BARs helping BARs

SAM 0044
AMA 352635
Reply With Quote
  #7  
Old 03-14-2010, 11:15 PM
CPMcGraw's Avatar
CPMcGraw CPMcGraw is offline
BARCLONE Rocketry
 
Join Date: Mar 2005
Location: Mobile, Alabama
Posts: 5,355
Exclamation Yet another version...

Here's the Mk III version, with polyhedral tips. The span is now 17".
Attached Thumbnails
Click image for larger version

Name:  Freewind BG Mk III 2D Base View.jpg
Views: 75
Size:  80.7 KB  Click image for larger version

Name:  Freewind BG Mk III 2D Side View.jpg
Views: 71
Size:  79.0 KB  Click image for larger version

Name:  Freewind BG Mk III 3D.jpg
Views: 75
Size:  27.6 KB  
Attached Files
File Type: rkt Freewind BG Mk III.rkt (46.2 KB, 72 views)
__________________
Craig McGraw

BARCLONE Rocketry -- http://barclone.rocketshoppe.com
BARCLONE Blogsite -- http://barclone.wordpress.com
BARCLONE Forum -- BARCLONE Forum

BARs helping BARs

SAM 0044
AMA 352635
Reply With Quote
  #8  
Old 03-15-2010, 07:03 AM
gpoehlein's Avatar
gpoehlein gpoehlein is offline
Paper Rocketeer
 
Join Date: Mar 2005
Location: Evansville, Indiana
Posts: 1,180
Default

I can't really tell much difference between 1 & 2, but they both look pretty good. I think what Kevin was really talking about was turning the tail upside down so the vertical control surfaces (rudder) are opposite the boost pod. Also, how many degrees of dihedral do you have there. Rule of thumb is that a dihedral of 15 degrees works about the best, and the dihedral should be wrapped around the boost pod (like you've done). Personally, I like simple dihedral such as you have in versions 1 and 2, and I find complex dihedral as in 3 a bit tedious. Again, the total dihedral should be about 15 degrees.

Greg
Reply With Quote
  #9  
Old 03-15-2010, 07:38 AM
CPMcGraw's Avatar
CPMcGraw CPMcGraw is offline
BARCLONE Rocketry
 
Join Date: Mar 2005
Location: Mobile, Alabama
Posts: 5,355
Default

Quote:
Originally Posted by gpoehlein
I can't really tell much difference between 1 & 2, but they both look pretty good. I think what Kevin was really talking about was turning the tail upside down so the vertical control surfaces (rudder) are opposite the boost pod. Also, how many degrees of dihedral do you have there. Rule of thumb is that a dihedral of 15 degrees works about the best, and the dihedral should be wrapped around the boost pod (like you've done). Personally, I like simple dihedral such as you have in versions 1 and 2, and I find complex dihedral as in 3 a bit tedious. Again, the total dihedral should be about 15 degrees.

Greg


For the Mk III version, the main wing panels are set for 10 degrees total (+ & - 85 degrees), and the polyhedral tips are at 90 degrees to each other. The stabilizer is set at 30 degrees (+ and - 75 degrees), and the rudders are at true 0 degrees.

The only difference between I and II was the location of the stabilizer attachment, and the shaping of the boom. The wing remained the same. There was no difference in the dihedral between any of the three.

As soon as I get some "housework" done (reconstruction of a wall in my computer room) I'm going to build one of each to see how they fly. I'm starting to get itchy fingers for this project...
__________________
Craig McGraw

BARCLONE Rocketry -- http://barclone.rocketshoppe.com
BARCLONE Blogsite -- http://barclone.wordpress.com
BARCLONE Forum -- BARCLONE Forum

BARs helping BARs

SAM 0044
AMA 352635
Reply With Quote
  #10  
Old 03-17-2010, 09:59 PM
GuyNoir's Avatar
GuyNoir GuyNoir is offline
NAR # 19250 - Life Member
 
Join Date: Sep 2008
Location: Woodstock, IL
Posts: 333
Default

More dihedral, man. More dihedral.
__________________
A dark night in a city that knows how to keep its secrets. But high above the quiet streets on the 12th floor of the Acme Building, one man is still trying to find the answers to life's persistent questions. Guy Noir, Private Eye.
Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump



All times are GMT -5. The time now is 03:43 AM.


Powered by: vBulletin Version 3.0.7
Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.
Ye Olde Rocket Shoppe 1998-2018