Dirty Birdy 60 (oz4915)


Dirty Birdy 60 (oz4915) by Joe Bridi 1975 - plan thumbnail

About this Plan

Dirty Birdy 60. Classic pattern plane.

Quote: "The Dirty Birdy is a new pattern ship by Joe Bridi whose Sun Fly (oz3946) series and Kaos (oz6251) pattern aircraft have become almost legendary in competition circles. All-up weight, including retracts, ranges from 7-3/4 to 8-1/2 lbs and, with a wing area of 688 sq in, this new ship has been expressly designed for the current AMA and FAI Patterns.

Since the first flights of the prototype, the Dirty Birdy has proven itself to be a superb pattern ship. The design makes it a gentle and rock steady flier with absolutely no snap roll tendencies. Even though the clean design makes a ship that moves out well in the air (from 80 to 100 mph), the landings are as slow as you'll want them to be. 2 degrees of down thrust is used on the engine with no right or left thrust required. Response to the use of the control surfaces is extremely smooth. A minimum of surface deflection is all that is necessary for it to perform to absolute perfection. As a result, the plane is a very predictable and reliable ship that you will really enjoy on those Sunday morning flying sessions or at contest time.

Since most construction articles presented in model aviation magazines are necessarily short due to space limitation in each publication, we have asked RCM's Contributing Editor, Ben Strasser, to present a complete step-by-step construction article with full material list in order that you may build the Dirty Birdy in the shortest possible time and with as complete a set of instructions as is possible to present. For this reason, this article is divided into two parts. The conclusion will appear in the July 1975 issue of RC Modeler Magazine.

In this first segment, you can assemble the materials while waiting for your set of plans to arrive from the RCM plans department. The canopy is available from the RCM Products Division and, when your plans arrive, you can proceed with Ben's instructions to cut out a complete 'kit' for yourself with the full construction of the aircraft appearing in the conclusion of this two part series.

PART I: If you want to get your own DB going, your first step is to put a kit together. To save you time, we've prepared a list of the wood and hardware you'll need to get the job done. It's at the end of this article so you can cut it out without messing up our glorious building notes. Before you begin cutting the parts though, there are some other comments we want to make. First and foremost, the hotter the engine the better. If you fly one of the real 'go-ers' like the new Webra, put in a 14 oz tank if you want to fly the whole pattern without running out of fuel. A Sullivan SS-14 fits well.

The size and shape of the canopy is critical for the superb flight characteristics of the plane. If you care about that sort of thing, the canopies are available from RCM Products Division PO Box 487, Sierra Madre, California 91024. You can, of course, make your canopy from a hollowed-out balsa block or make a plug and shape your own, if you've done a lot of scratch-building you probably have your own techniques for marking the wood to cut out the pieces. If this is one of your first attempts, one way is to work with a double set of plans. Cut up one set. Put household rubber glue onto the back of the paper pieces and glue them to the wood. Or do it the easy way and buy a set of RCM's adhesive backed templates for the plane with the plans.

As you read through the cutting notes that follow, watch for the marker (*). Each one means you've read everything about that part and you're ready to get your knife or jigsaw going. Now, to quote a friend of ours by the name of Marvin Barnsworthy: It's time to get a' whittlin.

The Fuselage Parts: The top block is cut from 3/8 x 4 inch balsa. Cut a 3/8 x 8 in slot in the back end of the top block for the two rear fin sections. See plans *. Cut the bottom block from 1/4 x 4 x 36 in balsa. Because of the thickness of the balsa, the bottom sheeting is cut in one piece *. The fuse sides are to be cut from 3/16 x 3 in balsa..."

Direct submission to Outerzone.

Update 19/06/2020: Added kit review (of Bluejay Airplane kit) from Flying Models, January 2009, thanks to RFJ.

Supplementary file notes

Article in 2 parts, thanks to Rocko.


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Dirty Birdy 60 (oz4915) by Joe Bridi 1975 - model pic

  • (oz4915)
    Dirty Birdy 60 
    by Joe Bridi
    from RCMplans (ref:602)
    June 1975 
    65in span
    IC R/C LowWing
    clean :)
    all formers complete :)
    got article :)
  • Submitted: 11/10/2013
    Filesize: 513KB
    Format: • PDFbitmap
    Credit*: MarkS
    Downloads: 9509

Dirty Birdy 60 (oz4915) by Joe Bridi 1975 - pic 003.jpg

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User comments

It should be noted the RCM plan service is not in business anymore and the canopy can be purchased through park flyer plastics http://parkflyerplastics.com/cart/index.php?main_page=product_info&cPath=46_64&products_id=608 ...I hope this will help in the search for the airplane mine came out perfectly.
Robert - 24/08/2015
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  • Dirty Birdy 60 (oz4915)
  • Plan File Filesize: 513KB Filename: Dirty_Birdy_oz4915.pdf
  • Supplement Filesize: 2612KB Filename: Dirty_Birdy_oz4915_article_1.pdf
  • Supplement Filesize: 2716KB Filename: Dirty_Birdy_oz4915_article_2.pdf
  • Supplement Filesize: 3924KB Filename: Dirty_Birdy_oz4915_review_FM.pdf
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* Credit field

The Credit field in the Outerzone database is designed to recognise and credit the hard work done in scanning and digitally cleaning these vintage and old timer model aircraft plans to get them into a usable format. Currently, it is also used to credit people simply for uploading the plan to a forum on the internet. Which is not quite the same thing. This will change soon. Probably.


This model plan (like all plans on Outerzone) is supposedly scaled correctly and supposedly will print out nicely at the right size. But that doesn't always happen. If you are about to start building a model plane using this free plan, you are strongly advised to check the scaling very, very carefully before cutting any balsa wood.


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