Sportwagon (oz5310)


Sportwagon (oz5310) by S Cal Smith 1949 - plan thumbnail

About this Plan

Sportwagon. Free flight sport cabin model.

Quote: "Build this attractive American cabin design and enjoy hours of trouble-free sport flying. Sportwagon, by Calhoun Smith.

This design has been flown with Forster 29 and Bantam -19 engines. Any of the new British diesels or petrol engines of between 2 and 5 ex, should be suitable - such as the ED Comp Special, Mills 2.4, Allbon 2.8, 'K' Vulture, etc. Reposition the bearers to suit the engine you chose.

THE Sportwagon has been designed for the average Sunday afternoon model fan - so those who favour hot contest designs should turn to other parts of this Annual. Most modellers have only limited flying time available and the best way to get the most out of it is with a good free flight sport design. No new records, no out-of-sight flights - just good looks, good steady flying and the ability to get home in one piece.

With a little careful consideration to free flight design proportions,a near scale appearance can be achieved. The sketch titled 'Design Evolution' will give you a brief outline of the numerous initial sketches we made for Ibis model. The swept back profile resembles the popular Aeronca Champion and the window arrangement roughly follows the tandem seating layout of the full size machine.

A glance at the 'Force Arrangement' diagram shows the location of the Centre of Gravity and the Centre of Lateral Area in relation to the thrust line. Charles Grant is to be thanked for this aerodynamic set-up, which ensures good flight stability.

The overall proportions follow accepted practice and include 6 to 1 aspect ratio, dihedral 1-1/2 in per foot of span, 45 percent tail moment arm, tailplane area 33 percent of wing area and fin area about 71 percent of wing area.

To sum up the design factors needed for sport flying : Underpower the model by using a high power loading of 150 to 200 ounce per cubic inch - and build for a wing loading of 7 to 11 ounces per 100 square inches of wing area, Use tough wood for strength and double covering for extra puncture resistance. Use large wheels and tough landing gear, because this type of model flies just like the real thing.

The plans are drawn to 1/4 in scale - that is, 1/4 in on the plans equals 1 in on the full size model. The scale plans will have to be enlarged to full size for building. Full size patterns are given for the tricky parts, so pinprick these directly on to the appropriate sheet balsa.

Construction of the fuselage is conventional box type - the main framework consisting of 3/16 in square hard balsa longerons, uprights and cross members. The engine mount is of the break-away type for airscrew and engine protection..."

Quote: "How about these from the Ian Allen "Model Aviation" series magazine 'Model Planes Annual', dated 1949, reprinted from 'Flying Models'. The short lived Ian Allen mags were, in my view, the best ever produced in the UK. These are scans of a copy, but pretty clear. It is a very attractive design, one I have long been eyeing up for electric R/C"

Supplementary file notes

Article pages, text and pics.


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Sportwagon (oz5310) by S Cal Smith 1949 - model pic


Sportwagon (oz5310) by S Cal Smith 1949 - pic 003.jpg
Sportwagon (oz5310) by S Cal Smith 1949 - pic 004.jpg
Sportwagon (oz5310) by S Cal Smith 1949 - pic 005.jpg
Sportwagon (oz5310) by S Cal Smith 1949 - pic 006.jpg
Sportwagon (oz5310) by S Cal Smith 1949 - pic 007.jpg
Sportwagon (oz5310) by S Cal Smith 1949 - pic 008.jpg

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User comments

I built Cal Smith's Sportwagon about 15 years ago and made it an R/C version. I loved the plane and the design. I believe that I found a set of drawings via Model Aviation magazine as I recall. Anyway, attached are some additional photos [see more pics 003 and 004].
ScottBlack - 19/11/2015
I am in the process of building the Sportwagon, during this covid lockdown, for Electric power with rudder/elevator controls. I scaled the plans up from the Flying Models mag, but was then given the later Model Aviation mag by chance. There are discrepancies on the plan however, which was a bind. the width of the centre section is wrong, being to narrow to match the fuselage. The ribs, that fit into the round tips do not fit being short as to where they should mate with the tip shape. I have increased the rudder size and added an elevator. Will update more when finished.
Brian Austin - 23/01/2021
Have now finished my version of the Sportwagon [pics 006-008]. A problem that has come to light, is that the positioning of the front band retaining dowel, causes the wing to be forced back from it's true position. Either use different wing retaining method, or position front dowel, so as it holds wing down, but does not force it back.
Brian Austin - 27/03/2021
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