S.P.A.D. Aircraft - Coroplast design Discuss the growing area of S.P.A.D.S. (Simple Plastic Airplane Designs). Coroplast type aircraft, pizza box planes, etc..

main spar alterations

Reply
Old 07-21-2011, 10:27 AM
  #1
flybyjohn
Thread Starter
 
Join Date: Jan 2004
Location: Helena, MT
Posts: 636
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default main spar alterations

I am new to spad design and I know the key ingredient is to keep it simple, however I have not run across a plan yet that utilized a double yardstick spar to its full potential. It may be out there, I just have not seen it yet and have searched a bit for it. I was thinking that if two yardsticks were to be used, then it would be the best configeration to have one stick vertical and rip the other stick lengthwise and glue it to the top and bottom of the vertical one to make a I beam out of it. this would put much more of the yardstick material in the tension/compression areas. Is this commonly practiced?
flybyjohn is offline  
Reply With Quote
Old 07-21-2011, 11:54 AM
  #2
flybyjohn
Thread Starter
 
Join Date: Jan 2004
Location: Helena, MT
Posts: 636
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: main spar alterations

I had another idea the other day also that some may be able to answer. Someone sugested using a dremel as a router or even a router to cut across one layer and through the flutes on the inside of the leading edge to make folding it much better with less stress on the plastic. I was wondering if you used this same technique to cut one layer on the inside of the wing off in squares, rectangles or circles with the router. Leave enought 2 layer material to make the wing ridgid but cut out uneccessary material out. This would save a bit of weight in the wing. I might try to do this with a flying wing I plan to make and see if the structure strength is still there.
flybyjohn is offline  
Reply With Quote
Old 07-21-2011, 09:54 PM
  #3
jimgee1
 
Join Date: Mar 2004
Location: Foster City , CA
Posts: 52
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: main spar alterations

John,

The early Debonair had a two yardstick wing. Nobody builds them that way anymore. Go to spadtothebone.com and look at all the free plans. You'll learn a lot just by browsing that site.

Craftman1 has a series of videos available on-line for spad construction. Look at norcalspads.com, too.

There's plenty of help on-line. Good luck..

Jim Gallagher
jimgee1 is offline  
Reply With Quote
Old 07-21-2011, 10:00 PM
  #4
jimgee1
 
Join Date: Mar 2004
Location: Foster City , CA
Posts: 52
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: main spar alterations

John,

I'm sorry. It's draftman1 who has the excelent videos, not craftman1 as I misstated in teh above post..

jimgee1
jimgee1 is offline  
Reply With Quote
Old 07-22-2011, 05:45 AM
  #5
Lnewqban
 
Lnewqban's Avatar
 
Join Date: Apr 2007
Location: South Florida
Posts: 4,039
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: main spar alterations


Quote:
ORIGINAL: flybyjohn

I was thinking that if two yardsticks were to be used, then it would be the best configeration to have one stick vertical and rip the other stick lengthwise and glue it to the top and bottom of the vertical one to make a I beam out of it. this would put much more of the yardstick material in the tension/compression areas. Is this commonly practiced?
Your thinking is correct; however, the plastic skin carries the tension / compression stresses.

The yardstick functions as a web or separator of both skins, and also to make the compressed skin more stable, preventing buckling.

In other words, the spar may or not be stronger than the plastic skin under stress by itself, but it would add weight and work for sure.
Lnewqban is offline  
Reply With Quote
Old 07-22-2011, 06:32 AM
  #6
Clean
 
Clean's Avatar
 
Join Date: Apr 2002
Location: Parkville, MO
Posts: 1,415
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: main spar alterations

USS uses that exact method, Yardstick center with top and bottom, though he uses trim strips instead, at the time we were getting terrible yardsticks that were spliced together scraps every couple inches. Stripped hardwood doesn't have that problem.

http://www.spadtothebone.com/SPAD/ul...34/page34.html

AND, they're excellant airplanes too.

Clean is offline  
Reply With Quote
Reply


Thread Tools
Search this Thread
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

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -8. The time now is 11:07 PM.