Cessna Bird Dog (oz8452)

 

Cessna Bird Dog (oz8452) by Eric Fearnley from Aeromodeller 1954 - plan thumbnail

About this Plan

Cessna Bird Dog. Free flight scale model.

Quote: "36-inch span flying scale model, for .5 cc motors. Cessna L19 Bird Dog, by Eric Fearnley

THE L-19 BIRD DOG (Cessna 305) was chosen for a flying scale model because it appeared to be a 'natural' for modelling. This has been proved true of our prototype, which combines the aerodynamic proportions of a flyer of inherent stability with the ruggedness of the sport model, yet retaining a true scale appearance with very simple con-struction. If this be your first scale effort, you have an ideal model, capable of being flown in a small field, in all but the roughest conditions, with the best possible chance of keeping it in one piece over a long period of flying activity. The prototype has had some months of flying, and to date, no repairs, major or minor, have been executed on it, and it retains its new appearance.

Any of the modern .5 cc engines can be used. Ample power will be available, and it is suggested that a rather larger prop than usually employed on this size engine will make for scale flying appearance, and also simplify trimming. A 7 x 4 should replace the normal 6 x 4 in.

Start construction with the fuselage by cutting out two sides from medium 1/16 in sheet, matching them for strength to simplify later assembly. The formers are cut from 1/8 sheet balsa, except F3, F4 and F5, which are from light plywood. Form the undercarriage as shown, and sew to the ply former F3.

Assemble the ply formers on the sides and when true and dry, add Fl, F6, F7 and F8. Fit the t h sheet pieces under the motor mount, and 'make sure they are parallel with the thrust line. Cut out the motor mount to suit your engine, and cement this in place, adding the 3/16 upper pieces, hollowed bottom, nose, and the tailskid blocks. When dry, carve to final shape, and sand smooth. Make the detachable cowl top from laminated 3/16. Cover the rear of the fuselage with pliable 1/32 sheet. Avoid hard, brittle wood. Cover the bottom using strips at the front end where compound curves are indicated, and in one piece at the back. Steam if any trouble is experienced.

Root ribs F9 and dowels arc added, making doubly sure that the incidence is true, and then add celluloid window frames, and tube to take struts for wings, etc.

The wing tapers from the halfway mark, so it is best to assemble in two stages - the root, straight section, and when dry, the tapered tips. The cut-out spar shows this change in taper. When removed from the building board, fix the strut fasteners, make the struts from dowel and sand smooth.

Nothing could be simpler, than the flat plate tail surfaces. Small trim tabs are an aid to trimming to allow for small errors in setting the tail incidence.

Cover the fuselage with lightweight and the wing and tail with heavyweight tissue, using sanding sealer on the fuselage and two coats of clear on the flying surfaces. Cement the tail surfaces in place after covering. European Bird Dogs are khaki with white lettering while those in the USA are aluminium with black letters.

Trimming should be easy, but don't be careless with it. Balance where indicated, after fitting motor with outside holes to allow side thrust to be adjusted. A small washer should be placed under the back of the motor lugs for temporary down-thrust. If a sharp left or right flight is indicated, apply sidethrust to correct, leaving the rudder alone at this stage. After a power flight, watch the glide. Too steep a glide is caused by not enough longitud-inal dihedral - in other words, put up the tail tabs a little. If a stall follows this on power flight, add downthrust. Alternatively, a stall on the glide calls for the reverse - less tail tab angle: and less down-thrust if it is not climbing on power. The original model is so foolproof that it has been flown with many different trims, and with engine sidethrust either way."

Update 26/02/2017: Added PDFvector version of the plan, thanks to hogal.

Update 19/10/2020: Added a 2-colour vector BW version of the plan file, thanks to Miguel.

Supplementary file notes

Article, thanks to Newtmagick.
Vector PDF.
Vector PDF BW print file.

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Cessna Bird Dog (oz8452) by Eric Fearnley from Aeromodeller 1954 - model pic

Datafile:

ScaleType:
  • Cessna_O-1_Bird_Dog | help
    see Wikipedia | search Outerzone


    ScaleType: This (oz8452) is a scale plan. Where possible we link scale plans to Wikipedia, using a text string called ScaleType.

    If we got this right, you now have a couple of direct links (above) to 1. see the Wikipedia page, and 2. search Oz for more plans of this type. If we didn't, then see below.


    Notes:
    ScaleType is formed from the last part of the Wikipedia page address, which here is https://en.wikipedia.org/wiki/Cessna_O-1_Bird_Dog
    Wikipedia page addresses may well change over time.
    For more obscure types, there currently will be no Wiki page found. We tag these cases as ScaleType = NotFound. These will change over time.
    Corrections? Use the correction form to tell us the new/better ScaleType link we should be using. Thanks.

Cessna Bird Dog (oz8452) by Eric Fearnley from Aeromodeller 1954 - pic 003.jpg
003.jpg
Cessna Bird Dog (oz8452) by Eric Fearnley from Aeromodeller 1954 - pic 004.jpg
004.jpg

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User comments

Steve, this is built from your Eric Fearnley Bird Dog plan [more pics 004]. Thanks,
PatO'D - 12/03/2017
Nice one Pat, that's a very pretty plane.
SteveWMD - 14/03/2017
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Notes

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Scaling

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