RC India

RC Models => Kites, Trains, Free Flight and All Others => Topic started by: Free Flight on September 06, 2022, 02:50:17 AM

Title: Yellow Bird 13
Post by: Free Flight on September 06, 2022, 02:50:17 AM
Decided to try this oldie glider again. The plans I used were from the Outerzone site. I still have a "blueprint" plans from the same kit that was purchased in 1984 from the Mumbai, IHC at Marine Lines then.

This is such an advanced glider. I am sure it did well as a hand launch glider, but I decided to make it a CLG.

Everything that the designer has done is optimum. Really a well thought off advance design for 1961. As you see in the video, even the trimming flights with no lift air approaches a minute in flight.

The fuse always use to break just behind the wing TE and it was impossible to get the incidence back. Hence the use of a carbon tube as the boom. Ready to fly weight is around 15 grams with no special light balsa wood. Only those pieces found in my balsa scrap box.

My modifications are: Carbon boom, Rudder turned 1/32 inch versus the recommended 3/32 as CLG go really fast and a badge viscos timer wing DT versus falling "dangling" weight fuse. Stab on my model is at Zero and wing incidence less then half a degree.

Hope you enjoy.



Title: Re: Yellow Bird 13
Post by: sanjayrai55 on September 06, 2022, 06:02:46 AM
Wonderful! Brings back many happy memories. The YB was my second model, after the Bobni. Both bought from the same place - IHC Marine Lines in the early 60s! To try to get a longer flight, I launched by climbing a tree. And of course, the fuselage broke :)

Sent from my moto g(9) power using Tapatalk

Title: Re: Yellow Bird 13
Post by: Free Flight on September 07, 2022, 12:08:22 AM
Thanks Sanjay.

It is a very well designed glider and so competitive to this day. His design encompasses all the salient features one finds in today's glider with no deviation.

This has been a lot of fun for me and am glad you liked it too. Did not grasp these things as a teenager, yet it flew so well with all the slob construction that it did tune me to further pursue model airplanes as a hobby.

Title: Re: Yellow Bird 13
Post by: Glidiator on September 07, 2022, 11:16:18 AM
 Copy book demo of what how CLG should perform.
Competitive CLG construction and trimming / flying  is an art and science that need good understanding of the aerodynamics of the different factors involved in CLG flight - very high speed at launch - low speed in glide.
Thanks to Free Flight for mentoring me in my first serious CLG - Hoosier.Kitty.
Final trimming flights soon now that rains have receded.
CLG is ideal for oldies like me who no longer have strong shoulders for a good Chuck throw.
Ihave about half a dozen Yellow Birds from IHC purchased about 15 years ago. . All balsa - but several differences in plan from the original one on Outerzone.

Title: Re: Yellow Bird 13
Post by: K K Iyer on May 04, 2023, 01:24:51 AM
Was looking at old posts by freeflight and found this thread.

The video is really worth watching again.

Title: Re: Yellow Bird 13
Post by: Free Flight on May 04, 2023, 07:06:52 AM
Thank you for your kind words.

YB 13 is still a very competitive model. Loved it then and still now.

Title: Re: Yellow Bird 13
Post by: Glidiator on May 04, 2023, 09:10:05 AM
How did you set the 1/32 rudder deflection on a straight carbon rod.?
With a 1/32 shim?

Title: Re: Yellow Bird 13
Post by: Free Flight on May 04, 2023, 09:57:23 AM
CLG needs very small off-set compared to HLG. Just a bit more than 1/64 of an inch. Done with small wires so it is adjustable.

Notice, had to move CG back when trimming. Added a bit of clay to the rudder as the nose had no additional weight (clay) to remove. Also harsh sandpaper at the rear for a firm hold when launching.