Septal III (oz9581)


Septal III - plan thumbnail image

About this Plan

Septal III - Double Header - Radio control contest model for rudder only. Plan shows 2 complete models at different sizes, for either .15 or 1/4-A power. Wingspans are 50in and 30in.

Quote: "Almost three years have passed since the first .15 Septal left the drawing board and work bench. From that time to the present, so many changes have been made on the ship, only three things remain the same as the original - the shoulder wing configuration, the pulse system and the name. Although the first one flew fairly well after being trimmed out, I wasn't at all pleased with its stunting ability. It was somewhat larger and heavier than the final version, and with a .15 up front, it just didn't have the steam I was looking for. Actually, it was more like an advanced trainer, although I could probably have boosted its performance by switching to a .19. I knew if I increased the power I would be defeating my purpose, for the popular .15 size engine was what I wished to retain.

The next version started to take on the appearance, if only in physical shape, of the final Septal III. Reducing the over-all size and shortening the nose moment arm, increased performance immensely. Changes in construction methods reduced the total weight, and the Fox .15 really moved the bird out. Maneuvers started tightening up, and over-all I could see a marked improvement. In some respects however, it still didn't qualify for the goal I had set for my dream ship. After many hours of flying and many CCG and decalage changes, I could see the Septal III much nearer. A broken B+ lead in flight ended any further testing on this version, but the information I received was all I needed to freeze the design. Many planes of the Septal II type were built and flown, and the Septal III, as it is now, was finally born. I realize now all the time and efforts spent were not without reward, as the Septal III has either won or placed in every meet entered. I would like to point out now that the .15 is strictly not a beginner's ship, but a high performing contest threat, capable of every rudder-only maneouvre, including true spins. Motor control is not just desirable, it is a necessity..."

Septal III, MAN, July 1962.

Direct submission to Outerzone.

Supplementary file notes

Article pages, thanks to RFJ.
Article pages (same, but OCR) thanks to rchopper56.


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

Septal III - completed model photo

  • (oz9581)
    Septal III
    by Stan John
    from Model Airplane News
    July 1962 
    50in span
    Tags: IC R/C
    all formers complete :)
    got article :)
  • Submitted: 15/12/2017
    Filesize: 932KB
    Format: • PDFbitmap
    Credit*: Circlip, RFJ, rchopper56


Do you have a photo you'd like to submit for this page? Then email

User comments

I built the .15 size Septal in the spring of '63. Learned to do all of the stunts that a single channel could do with this plane and to date it is still my favorite. Used a home made pulse actuator from a micro mo motor with bang bang throttle control. Dad built the smaller one several years later but it could not perform like the .15 size.
rchopper56 - 22/12/2017
Add a comment



Download File(s):


* 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.


Terms of Use

© Outerzone, 2011-2019.

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.