Rearwin Skyranger (oz12250)

 

Rearwin Skyranger (oz12250) by Doc Mathews from Model Airplane News 1982 - plan thumbnail

About this Plan

Rearwin Skyranger. Radio control sport-scale model.

Quote: "Realistic looks and performance in a small package that builds quickly. Silhouette Scale. Rearwin Skyranger by Dr DB Mathews.

FOR YEARS I have been itching to build a Rearwin Skyranger. This silhou-ette scale Skyranger project was inspired by a superb 1/5-scale design by Gene Salvay published in MAN, November 1970. His background as an employee of the Rearwin Aircraft Company in pre-war Kansas City had inspired an exact scale model of great beauty, but complex structure.

My desire to develop an easy to build, light-weight, and smaller version was enhanced by a photo in Vintage and Veteran Aircraft Guide. The custom paint job on that particular version was more attractive than the solid color factory version. They don't even look like the same aircraft.

As presented here, the Skyranger is simplified structurally. I have taken liberties with the contours, but the model is still reminiscent of the prototype, both statically and in flight.

THE PROTOTYPE: Designed in 1939 as a replacement for the popular Sportster, the Skyranger was first flown in April 1940. Engineer Robert Rummel saw his work enter production in August 1940, and this version was powered by either a Continental 65 or 80. Production continued through early 1942 with a total of 82 units sold. After WW II, the production rights were purchased by Commonwealth, and an additional 275 units were produced. Approximately 90 Skyrangers are registered in the US, and they can often be seen at fly-ins and in hangars around small airports.

THE MODEL: This 1-1/2 inch to the foot cutie is intended for .15 cubic inch glow or .10 cubic inch Davis Diesel converted power. Power was marginal with a glow form of the O.S. Max 10FSR. A change to the Davis Diesel head, and a 9x4 or a 10x4 prop brought the model to life. If you don't own a Davis conversion, I recommend a sport .15 capable of turning a 9x4 prop at a reasonable speed. The silhouette scale concept emphasizes simplicity coupled with lightness, relatively low power, and slow flying speeds. The Skyranger fits those parameters well. The double curvature of the fuselage cross section was eliminated, and the stab mount simplified. Both changes are barely discernible, even to those well acquainted with the prototype. Don't let anyone criticize the deviations, they are there for a reason. The dimensions and outlines are quite close to true scale, however. The wheel pants were used primarily for decoration, and they make grass takeoffs nearly impossible. The flight photos were taken from a hand-launch start - something this model responds to very well. Other performance areas are just plain delightful. In fact, the model is as gentle as a pussycat all the way.

CONSTRUCTION: All balsa and spruce joints are glued with aliphatic resin glue, such as Sig-bond or Titebond. Five-minute epoxy was used on all plywood joints. Wood sizes and hardware items are all standard hobby shop items, and no unusual tools or equipment are required, just the usual hand tools. Take care in choosing wood grade and density. The model's weight is not critical, but the lighter she is, the better she'll fly.

TAIL GROUP: The empennage is straight-forward and simplified. I find it easier to cut the tip outlines after assembly. The wire elevator connector is more easily epoxied if it is done before separating the halves. Install the hinges after covering, using a toothpick section pushed through a pre-drilled hole, and secured with instant glue.

WING: A plywood master rib pattern can be developed with carbon paper, tracing paper, or ironed on from a Xerox copy. Cut the ribs from stacks of light C-grain sheet using a jig saw, or by carving and sanding.

Build the wing panels from the bottom up, over the drawing. Cut bottom spars flush with the outside of the tip ribs, position the light ply tips, then cut the top spars to match the tips. The center section is built integrally with the left wing panel, then cut away.

By tilting the inside wing ribs, and using the jig, I only needed to block up the wing panel and sand in the bevel using a table edge as a guide.

No dihedral gussets are shown on the plans as my experience has taught me a better way to develop a good fitting joint. After the three sections have been epoxied together at the correct dihedral angle, cut through the ribs using hack saw blades taped together. Place a blank section of plywood into the slots, and mark top and bottom outer lines. Remove and cut the ply to the lines, and you'll have a gusset that fits the exact dihedral angle.

Carve the leading edge to outline, sand the entire wing, and set it aside for use in the fuselage construction steps.

FUSELAGE. Two identical sides are constructed in the classic technique. The triangular stock is fitted for the firewall, and the bulkheads are fabricated directly over the plans. All holes are located and drilled, and the basic box constructed. Pin the right unit flat over the side view, install the four major forward section units, check for squareness with a triangle, and epoxy them into the slots in the right side.

Inset the left side onto the bulkheads to complete the forward fuselage box. Block up the tail post at the mid line, and pull the left post down onto the right one. Cut balsa cross pieces to length over the top view, and glue them in place with the fuselage still pinned down on the board.

Epoxy the wing saddles in after the fuselage is free of the board, and epoxy the 3/16 dowel onto the front saddle with the fuselage inverted. This needs to be in the center line. Place the completed but uncovered wing onto the saddles and drill a hole through the trailing edge down into the plywood mount. Either epoxy a pre-threaded hardwood block or appropriately tap. If the block is used, lubricate the nylon bolt to pull the block up tightly against the underside of the ply mount.

With the bolt still in place, position the 'wing grabber' onto the protruding dowel, then epoxy it to the rear spar faces. Add the windscreen frame and filler blocks with the wing still in place. Carve the blocks to blend with the wing contour before removing the wing. Allow some extra room for the thickness of the windscreen material..."

Rearwin Skyranger, Model Airplane News, November 1982.

Direct submission to Outerzone.

Supplementary file notes

Article pages, thanks to RFJ.

Corrections?

Did we get something wrong with these details about this plan (especially the datafile)? That happens sometimes. You can help us fix it.
Add a correction

Rearwin Skyranger (oz12250) by Doc Mathews from Model Airplane News 1982 - model pic

Datafile:
  • (oz12250)
    Rearwin Skyranger
    by Doc Mathews
    from Model Airplane News
    November 1982 
    50in span
    Scale IC R/C Cabin Civil
    all formers complete :)
    got article :)
  • Submitted: 18/02/2020
    Filesize: 676KB
    Format: • PDFbitmap
    Credit*: Circlip, RFJ

ScaleType:
  • Commonwealth_Skyranger | help
    see Wikipedia | search Outerzone


    ScaleType: This (oz12250) 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/Commonwealth_Skyranger
    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.

Rearwin Skyranger (oz12250) by Doc Mathews from Model Airplane News 1982 - pic 003.jpg
003.jpg
Rearwin Skyranger (oz12250) by Doc Mathews from Model Airplane News 1982 - pic 004.jpg
004.jpg
Rearwin Skyranger (oz12250) by Doc Mathews from Model Airplane News 1982 - pic 005.jpg
005.jpg

Do you have a photo you'd like to submit for this page? Then email admin@outerzone.co.uk

User comments

No comments yet for this plan. Got something to say about this one?
Add a comment

 

 
 

Download File(s):
  • Rearwin Skyranger (oz12250)
  • Plan File Filesize: 676KB Filename: Rearwin_Sky_Ranger_oz12250.pdf
  • Supplement Filesize: 3807KB Filename: Rearwin_Sky_Ranger_oz12250_article.pdf
  • help with downloads
 

Notes

* 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.

Scaling

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.

 

Terms of Use

© Outerzone, 2011-2020.

All content is free to download for personal use.

For non-personal use and/or publication: plans, photos, excerpts, links etc may be used, provided that full and clear credit is given to Outerzone with appropriate and specific direction to the original content i.e. a direct hyperlink back to the Outerzone source page.

Unauthorized use and/or duplication of this material without express and written permission from this site's owner is strictly prohibited. If we discover that content is being stolen, we will consider filing a formal DMCA notice.