Tuesday 10 June 2014

Top Flite Freshman


The Freshman was designed by Dan Santich.  I know this from an article in the November 1978 issue of RCM, where he had his Magnum 40 design published.

For more info, see his AMA bio

As a 12 year old, this was the first RC airplane I ever got to take the controls of and so it has some sentimental value.  The kit came onto the market in 1977 and was discontinued, probably around the time of the aquisition of Top-Flite by Hobbico in 1990 and the Gold Edition lineup, where the Sierra trainer was introduced.  Thus, it has become an endangered species.  The plans are available from Top-Flite or the AMA plans service.  However, without the fuselage formers and other details, it is impossible to build an accurate model.  I didn’t want to see this airplane become lost to history, so I found a “new in box” kit to take measurements from and document the pieces missing from the plans.  I figure this kit has traveled at least 7000 km, having gone from the factory in Chicago to Phoenix, AZ, on to Texas and finally arriving at my door, here in Canada.


There seemed to be two trains of thought when it came to learning to fly.  The first was to basically take a free flight airplane and give it some measure of control.  These types of airplanes were your high wing, lots of dihedral, flat bottom airfoil types, like the Sig Kadet ( or even the Cub ) and Goldberg Skylane ( the Eagle was not yet available ).  Then, there was the other idea, where you take a pattern type airplane, which goes and stays where you put it, so the pilot isn’t fighting the stability, especially in wind.  Airplanes like the Goldberg Falcon, Ugly Stik, Sig Komander or Top Flite’s own Tauri trainer would fall into this category.  As long as they fly slowly and the controls aren’t too sensitive, they should make fine trainers.  The Freshman was probably designed to replace the aging Tauri.  It’s interesting how Sig’s Kavalier was introduced around the same time as the Freshman and bears a very strong resemblance to the old Tauri trainer !  As I write this, you can still buy a Kavalier kit from Sig!

Let’s get on with the design.  It strongly resembles the Tipsy Nipper, a full size homebuilt airplane that was designed to be easy to build, maintain and fly.


Mr. Santich also seemed to be influenced by the Boeing P-26 for the rear cockpit area and overall colour scheme.


He was in the USAF after all and would publish ¼ scale P-26 plans a few years later ( Sep 1982, Model Airplane News ).  Perhaps, he already had it in mind when designing the Freshman.

Wing

The wing is rectangular with airfoil shaped, block wingtips.  It measures 48” x 10-3/8”, including the ¾” ailerons ( +/- 3/8”, 30 degrees ) and wingtips.  There are two spars ( ¼ x ½ balsa ), centered at 3.5” from the leading edge, in the top and bottom of the 3/32” balsa ribs.  The ribs start 2” from the centerline, with 2-29/32” space between ribs, except for the last bay, which is 2-13/16”.  The tips add another 2” to the span.  The center section is sheeted with 3/32” balsa out to the first ribs, top and bottom.  The thick airfoil is a NACA 1417 with the last 1/8” rounded off.  If you build from a kit, the substantial leading edge is pre-shaped with a ½” x ¼” span-wise groove, where the ribs notch into it.


Tail

The tail surfaces are 3/16” balsa sheet.  The horizontal tail is of constant chord and measures 5-1/4” x 18”, including the 1-1/4” elevator, with 3/8” travel ( 17.5 degrees ).  The tail moment is 22”.  The fin leading edge sweeps back 24 degrees to a height of 6-5/32” above the stabilizer, where the chord is 3-7/16”, including the rudder, which is 1-1/8” at this point.  Total rudder area is approximately 11 sq in.  The hinge line extends down to the bottom of the fuselage 7-7/8”.  The rudder moves ½” either way.


Power

The plans call for a 0.29 – 0.40 engine.  The model I flew back in 1985 was powered by an OS 40.  There is no right thrust and 1 degree of down thrust ( the wing and horizontal stabilizer are at 0, as far as I can tell ).

Landing gear

The wheelbase is 9-1/4” with the main wheels ( 2” diameter ) located 1-3/8” behind the empty CG, which is exactly 3" behind the leading edge ( 28.9% chord ).  Plans call for a 1-3/4” nose wheel.  Ground clearance for a 9” propeller is 1-1/2” ( or 1” for a 10” propeller ).  The ground angle for tail clearance is about 12 degrees.  There was a revision issued with the kit, where the landing gear is modified to give an extra 1" ground clearance with 2-1/4" wheels all the way around.  The main wheel track is about 14.5".

Construction

Mine isn't finished yet, but you can check out the RCM review, from March 1978 here,


I'm planning on covering it like the box, except using Cream Monokote instead of white, for that vintage look.  The red will be a Metallic Red, along with Insignia Blue.


2 comments:

  1. Excellent article. Excellent model. Thank you! This is class!

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  2. Do you have any tips on how best to align fuse sides when gluing. The instruction illustrations are clear as to what exactly they want you to do? The first one I built I put the formers 90 degrees and fuse came out longer on one side due part F4 not matching up. Please advise.
    Jesse Paz
    jessep3m@att.net

    ReplyDelete