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Mar 12, 2016, 05:50 AM
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Paul_BB's Avatar
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Build Log

1/2A Jr Falcon


Some (a long) time ago I was 13 and had just built a 1/2A Skylane fitted out with a cumbersome RC system. I was trying to learn to fly and my poorly built model didn't survive its maiden. As I was wipping my tears while gathering with my brother the remains of the ill fated Skylane, I heard overhead the familiar buzzing of a .049. I waited for the model to land and rushed towards its pilot, a grown-up of at least 20 year of age. He had built and was flying very successfully a Jr Falcon fitted out with a Cannon Tini series RC system.
Now it's my revenge, I also want to have fun with the Jr Falcon.

I found two plans of the Jr Falcon. The first one I have found on HPA seems to be the original plan and the second one I have found on OZ is a modern redrawn plan in PDF vector format, from Dave Fritzke originally.

The problem with these plans is that their scale are not exactly the same:
- the wingspan as measured on the original plan is equal to 37" 3/8
- the wingspan as measured on the redrawn plan is equal to exactly 37"

On the box is is written that the wingspan is 37" but I read somewhere on the Internet that the Jr Falcon wingspan is equal to 37" 1/2.

I know that I am nitpicking but there is another problem: the wing is not built the same way on the two plans. The spars are not located at the same place.

And worse, the airfoils are different.
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Mar 12, 2016, 08:55 AM
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Gunnymike's Avatar
In my youth I once tried to trade my older sister for a Cannon radio system. She was less than thrilled with the idea. The modern ribs look to me to be easier to cut and to build straight. You going to cut your own or go the laser route?
Mar 12, 2016, 09:12 AM
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Gunnymike's Avatar
For what it's worth, Rubbernecker cuts a Jr. Falcon short kit for a pretty darn decent price. I think it also comes with a canopy.
Mar 12, 2016, 10:30 AM
pd1
pd1
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I have an original Jr Falcon kit. i will measure the wingspan later today.
Is there anything else you want checked?

Paul
Mar 12, 2016, 10:45 AM
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I built the 1/2a Skylane back in 1973. It's still sitting unfinished in my basement. You could have it if you lived nearby. (smile)
Mar 12, 2016, 10:55 AM
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Paul_BB's Avatar
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Thanks guys.

Quote:
Originally Posted by Gunnymike
In my youth I once tried to trade my older sister for a Cannon radio system. She was less than thrilled with the idea. The modern ribs look to me to be easier to cut and to build straight. You going to cut your own or go the laser route?
I also had an older sister but never thought about trading here for the Cannon. I was so dumb at that time.

I'm gonna cut my own kit and try to stick to the original design, going down memory lane.

Quote:
Originally Posted by Gunnymike
For what it's worth, Rubbernecker cuts a Jr. Falcon short kit for a pretty darn decent price. I think it also comes with a canopy.
I have already ordered two canopies at Park Flyer Platics. I will try to bend my own nose gear.

Quote:
Originally Posted by pd1
I have an original Jr Falcon kit. i will measure the wingspan later today.
Is there anything else you want checked?
Thanks Paul, yes, if you could measure the half wingspan very accurately on your plan. This should make my day.
Mar 12, 2016, 11:02 AM
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Paul_BB's Avatar
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Quote:
Originally Posted by 706jim
i built the 1/2a skylane back in 1973. It's still sitting unfinished in my basement. You could have it if you lived nearby. (smile)
Lol
Mar 12, 2016, 01:14 PM
pd1
pd1
Registered User
The wingspan on the cover of the box is 37 inches.
The wingspan on the plans also is 37 inches.
The plan half span measures exactly 18 1/2 inches for 37 inch span.

If you want I can resize the plan from HPA to be 37 inches.

Paul
Mar 13, 2016, 12:42 AM
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Paul_BB's Avatar
Thread OP
Quote:
Originally Posted by pd1
The wingspan on the cover of the box is 37 inches.
The wingspan on the plans also is 37 inches.
The plan half span measures exactly 18 1/2 inches for 37 inch span.

If you want I can resize the plan from HPA to be 37 inches.

Paul
Thanks Paul. So the HPA plan is found guilty.

I read somewhere on RCG that the Jr Falcon is a 2/3 scaled down version of the Falcon 56, but that is not true. 2/3 times 56" is not exactly equal to 37".

Yes I would be grateful if you resized the plan from HPA. Thank you very much.

Paul
Mar 13, 2016, 12:56 PM
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jpurcha's Avatar
I picked up a set of plans for the Falcon Jr with an additional sheet with the balsa parts traced on the back. If GP or Hobbico had introduced the foam Jr Falcon as a balsa ARF, I wouldn't have thought twice of purchasing it. But $80.00 for a foam ARF?

Jim
Latest blog entry: MAAC Wings
Mar 13, 2016, 01:39 PM
pd1
pd1
Registered User
Here are the plans. I adjusted the size of the plan to make the half span exactly 37 inches.
I also joined the right wing tip to the wing. I found that the right wing was skewed and re drew it.
Should be fine to build on now.

Paul
Last edited by pd1; Mar 14, 2016 at 07:04 AM. Reason: Right wing was off 1/16. now corrected
Mar 13, 2016, 03:08 PM
I'd rather be flying.....
JeffMac's Avatar
Hi Paul -

nice choice with the JR Falcon ..... I also built a skylane 42 but it was so heavy i never completely finished it..... ended up tossed out..... I do have a plan somewhere of the JRF and still have the sklyane plan....

best regards,

jeff
Mar 13, 2016, 07:13 PM
Registered User
Those airfoils are much closer in shape than they appear in your overlap. You have them at different incidences. The trailing edges match, so line them up so the leading edges match too. It's a NACA something-or-other, I've forgotten which number.

Anyway, you could adjust for the slight difference or just ignore it, it will fly and look the same.

Jim
Mar 14, 2016, 02:36 AM
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Paul_BB's Avatar
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Quote:
Originally Posted by jpurcha
But $80.00 for a foam ARF?
Disgusting LOL

Quote:
Originally Posted by pd1
Here are the plans. I adjusted the size of the plan to make the half span exactly 37 inches.
I also joined the right wing tip to the wing. I found that the right wing was skewed and re drew it.
Should be fine to build on now.
Thank you very much Paul This is a significant help.

Quote:
Originally Posted by JeffMac
Hi Paul -
nice choice with the JR Falcon ..... I also built a skylane 42 but it was so heavy i never completely finished it..... ended up tossed out..... I do have a plan somewhere of the JRF and still have the sklyane plan....
Hi Jeff, I have also considered building a 1/2A Skylane but I prefer the Falcon. I think the Skylane has a sort of chubby look. And the building is pretty complex if you take a look at the plan.

Quote:
Originally Posted by buzzard bait
Those airfoils are much closer in shape than they appear in your overlap. You have them at different incidences. The trailing edges match, so line them up so the leading edges match too. It's a NACA something-or-other, I've forgotten which number.

Anyway, you could adjust for the slight difference or just ignore it, it will fly and look the same.
Hi Jim, you are right the airfoils are pretty similar. I've read somewhere that the Jr Falcon glides very well so I'm gonna stick to the original airfoil. And with the front and rear spars in the middle of the airfoil thickness (depth wise), rather than flush with the upper and lower surfaces.
Mar 14, 2016, 07:04 AM
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rchopper56's Avatar
Hi,
I drew the CAD plan and intentionally changed the wing structure. At the time it was drawn, both Dave and I were concerned about copy write issues. Also, my experience with Goldberg wing structure - his wing structure designs folding in mid flight. Being an engineer, I chose an I beam that uses less material resulting in a lighter, stronger, and stiffer design.Changing the design to overcome the copy write issues.

The wing span difference, I suppose that I took the box cover as gospel. You will also find that I used the same wing design for my CAD Jr Skylark drawing from 2006.

The Jr Falcon was my favorite model as a teenager and wanted to share my experiences with this design. My cad drawing is from 2004, long before plans became freely available on the Internet.

Gene Rock


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