rrengineer

My Feedback: (3)

I am building an original Jr. Falcon kit I won on Ebay. It is one of the later kits manufactured just before production ceased. I am now at the wing construction phase and am trying to put the two wing halves together. The problem is that the plans call for a 5-1/4" dihedral total. The dihedral braces don't match this angle the way they are cut. I also have a much older Jr. Falcon kit (the wood has even darkened) and these plans call for 4-1/4" dihedral. From the looks of the dihedral braces I'm leaning towards 4-1/4". Anyone of you Jr. Falcon fans ever run into this?

Andrew

Dave Fritzke's plans show 6 degrees under each panel.

rrengineer

My Feedback: (3)

Well, let's see, 12 degrees total. I guess I'll have to get my 16 year old son to do some trig for me to figure out the verticle leg of the triangle in inches.

Sneasle

id run the numbers for you real quick if you gave me a wing span.


just plug and chug this eqn.. you can find a trig function calc easily. ...

(1/2 total wingspan) * sin 6 degrees = height from wing tip to horizontal line that intersects with wing root.

rrengineer

My Feedback: (3)

Well just for kicks, the toal wingspan is 37 inches. Not that it matters, just would be interested in the dihedral on the cad plans for Dave Fritzke's version. I talked to Bob Harris, formerly of Early R/C. He uses 4-1/2 inches total dihedral on his retro lazer cut kits, so I went with the 4-1/4 inch reccomended on the older Goldberg plans I have.
Mike

MajorTomski

How do you intend to fly the plane?

Rudder only like the original? Then go with the 6.

Ailerons? go with the 4.

T

rrengineer

My Feedback: (3)

The orignal "early" Goldberg plans call for 4-1/4 inches total for a single channel plane. Bob Harris retro plans on his lazer cut kits calls for 4-1/2 inches of dihedral. I suspect 6 degrees in each panel is about the same. I will be flying this single channel with an Ace pulse system (is there any other way?) If I was to make this a 3 channel airplane which seems rediculous anyway, I would take out most if not all of the dihedral. Anyone do the math on the 6 degree per panel of a 37 inch wingspan yet? That would be 12 degrees total wingspan.
Mike MacLean

rainedave

My Feedback: (1)

I failed most of my HS math classes, so I used my CAD program and I got 1.93" for an 18.5" line drawn at 6 degrees:

rrengineer

My Feedback: (3)

So, that is very close the original 4-1/4 inch dihedral that the early original Goldberg plans call for and a 1/2 inch less than Early R/C's kit. I went ahead and put my wing together at 4-1/4 inches and split the difference. I take it the later Goldberg plans was a typo at 5-1/4 inches. I wonder how many newbies back in the day put that much dihedral in their Falcon kits and how did it fly?
Mike MacLean