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View Full Version : Question Who'll build me a Bird of Time Wing?


michaeljt
Feb 10, 2004, 06:17 PM
Is there anyone out there, that will build me a Strong Bird of time wing?? Maybe not one that would take a full pedal winch launch, but one that will not fold under a strong winch. I don't trust the BOT wing after so many have folded using a winch.

I would also be interested if someone could strengthen the one I have.

AcintSpec
Feb 12, 2004, 06:44 PM
michaeljt:

You could probably make the mod to your present wing yourself. One of the best things to do is carefully remove the covering in the vicinity of the spar. Glue in new shear webbing that fits the space between the upper and lower spars, aligning the web material so that the grain is up and down between the spars. The more exacting the fit, the stronger the joints. If for example the spars are 3/8 inch wide, use 3/8 balsa as a material.

R/
Gene

michaeljt
Feb 12, 2004, 11:08 PM
I found someone.

ercouper
Feb 18, 2004, 09:04 PM
Michaeljt:

I did just that, removed the white covering on the center section, removed all the 1/16" horz. balsa shear webs, I setup a fence on my saw and cut 3/8" vertical grain basal shear webs to a tight fit, coated with yellow glue, and slid them in to place, I don't think the tip section will need any work, as the center section takes most of the load, but remember this is a balsa, and hard wood constructed wing.

Happy soaring

ercouper, MRCC

Ollie
Feb 19, 2004, 05:46 AM
Shear webs that are 1/16 of an inch thick at the center of the wing will fail in shear with a line tension somewhere between about twenty and forty pounds, depending on the density of the balsa used in the shear webs. This result applies to webbing with either vertical or horizontal grain direction. The main advantage of vertical grain over horizontal grain is that it resists buckling in the top (compressed) spar cap better.

In my opinion, the prudent thing to do when launching a stock BOT ARF wing is to use a short piece of 20 pound test monofilament in series with the launch line to act as a fusible link so that the link breaks before the wings fold. This is called for even with histarts if the histart can withstand over 20 pounds of tension.

michaeljt
Feb 22, 2004, 06:39 PM
Just incase anyone is interested, this link will take you to a website where you can purchase BOT laser cut ribs. This is also the person, I was refered, to build me a BOT wing that will withstand a full pedal winch launch. Also he's installing spoilers while he's at it.

Laser cut ribs for the Bird of Time
All wood is hand selected "C" grain
The inner root ribs are rock hard
The main panel ribs are #4-6 Contest Grade
The tip panels are #4-6 Contest Grade
The ribs were CAD from Dave Thornburgs' original plans he submitted to RCM

http://www.soaringspecialties.com/contact.shtml

ameimen
Mar 09, 2010, 08:38 AM
I might suggest a carbon fiber rod be glued in along a spar.

Miami Mike
Mar 09, 2010, 09:25 AM
Resurrected a thread after six years! I wonder what the record is.

SPasierb
Mar 09, 2010, 08:20 PM
I'll do it! I need $6000 and a case of Jim Beam. Oh, and a couple years for delivery.