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Sep 28, 2014, 07:13 PM
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Build Log

OneSheeter #16 OSK - Kestrel (a Goldberg Falcon tribute)

caveeagle and I have been discussing a plane that he flew "back in the day" and wants to build a foamie version: Carl Goldberg's Sr. Falcon. While he was familiar with the plane, I wasn't, being out of the hobby, getting married, raising kids, etc, etc "the rest of life". When I did a bit of research on it, I found it was a really popular plane, and was done in several variations and sizes and there were a fair number of plan sheets out on the web. While he was pondering working right off the original plans and building one from scratch, I got thinking about doing it as a onesheeter, and one evening went into a fit of creative passion (well, maybe not a fit....) and came up with a foamie version. We are going to both build one and compare notes. Thanks to my favorite Laser Lady, we will be using laser cut parts from Model Plane Foam. Of course, these first go arounds will inevitably have mistakes, and missing parts (that I forgot) so be aware the templates aren't finalized. I used the Jr. Falcon plans to build the foamie version fyi.

I forgot to mention the Kestrel is a small falcon native to most of North America. It is one of the smaller ones that we see hovering above the freeway medians getting ready to pounce on those little mice! So, we are doing a little Falcon.....

edit 10/23, here's a second flight day video:
osk 10-23-14 (3 min 11 sec)

Here's a couple pix of the originals:

10/25/14 and a picture of the finished foamie:
Last edited by springer; Oct 25, 2014 at 10:36 AM. Reason: added video
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Sep 28, 2014, 07:13 PM
springer's Avatar

templates pdfs, etc

We are doing the MPF version with almost a 40" span, but I also created a Readiboard version with 36" span. I will upload the MPF version first. Again, remember these aren't built yet, so may be missing parts, etc.

templates for wire landing gear added 10-20-14

9-20-15: Readiboard version templates pdf's posted per request.

10-14-2017 update: Uploaded files for the rev 3 version. This includes a .5" longer nose, no taper on the fwd fuselage, and Wing LE formers shortened to fit longer batteries in fuse. I also added a PDF of the three ply parts. More pics of a virtual build are on page 7 of this thread.
Last edited by springer; Oct 14, 2017 at 04:49 PM.
Sep 29, 2014, 08:35 AM
Looks like the start of another great One Sheet design.

I never had a Falcon but I did have a Carl Goldberg Ranger 42. It may have been the original foamie. At least it was the first foam plane I ever saw. Mine was rudder and elevator only. Power was a Cox Tee-Dee .049. It was my first really successful RC Plane. It had a used 3 channel Kraft single stick proportional radio. Third channel was a rotary knob on the end of the stick, normally used for throttle. The plane flew great. It traveled with me on military reserve camp outs and vacations around MI. One day I was flying and a young (8-10 yr. old) lad came to watch. He jumped at a chance to fly it, when I offered. He flew around for several minutes following my instructions and doing a nice job. Then for some reason he started to push the stick forward. A shallow dive kept getting steeper despite my instructions to pull back on the stick. I kept saying pull back, pull back! He finally did. Just as the near vertical dive was about to enter the top of a large tree. Wing folded and fluttered down as the fuse went right through the heart of the tree. Miraculously, the pieces all came down and were soon glued together and flying again a few days later.

Check out the Ranger 42. Photo of plans here.
Last edited by bz1mcr; Sep 29, 2014 at 08:48 AM.
Sep 29, 2014, 11:32 AM
springer's Avatar
Wow, Goldberg sure did a bunch of planes on that same basic set of specs! Ranger looks like the same plane with a cabin instead of canopy. While searching, I noticed his skylark a low wing plane on the same general plan. If it aint broke, don't fix it!

And a very early testimonial of foam's repair-ability, too!
Sep 30, 2014, 12:22 AM
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I am looking forward to this build. I have been thinking about adding ailerons to the OSF for a while, but decided I would rather leave that plane alone and work on another plane to serve as a good 4ch trainer. I am very pleased that to have Springers plans to work from!

Here is the gear list I am planning to use:
-Emaz CF2812 motor
-Hobbywing Slywalker 20amp ESC
-32 1300mAh battery
-Fixed trike gear
-9g Towerpro servos

Here are some vintage pics from 1986:
First pic was taken at Kuhberg Hill Army Rec Center field. Bad Kreuznach, Germany.
Oct 07, 2014, 10:08 PM
springer's Avatar
Wow! You are gonna have yours done before i get mine started!

All looking good!
Oct 09, 2014, 05:32 PM
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caveeagle's Avatar
Just got back in town and found a package full of RC gear arrived in the mail!!
...That never gets old.

Looks like the motor will fit great with a little foam clearancing. I will need to get creative with the bottom cover to make sure battery access is smooth and easy. I hope balance turns ou ok, because I don't have much option to move the battery.
Oct 10, 2014, 09:05 AM
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caveeagle's Avatar
I am planning ailerons similar to the OS #12 Edge, using cofee straws to actuate the control surfaces.

I need to decide if I want to put the aileron linkage, and control horns above or below the wing. Below seem like the obvious choice, but in some models I have notices more travel on the same side as the control horn. (maybe I am doint it wrong)

In any case, I am planning on putting a small canopy on top of the wing, so I could easily hide/protect the servo and linkage.

I would rather not force the coffee-straw through the middle wing panel, so I think the servo 'top' should be on the same side as the ail control horns.

...I am probably over-thinking this.
Oct 10, 2014, 09:09 PM
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This is the first time I have used XT60 connectors. They are MUCH easier to solder that the Deans connectors i have used. They seem a little tough to pull apart, but maybe they will loosen up a bit.
Oct 10, 2014, 09:19 PM
Brings back memories of my old Falcon 56.......

Is that EPP ? Kinda looks like EPP when you enlarge the pics.


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