Optimist III (oz16250)
About this Plan
Optimist III. Free flight sport model for rubber power. Wingspan 44 in.
Direct submission to Outerzone.
Note this is not a full size plan. Wing and fuse layout are shown at 25%, as printed in the original pages.
Update 4/9/2025: Added article, thanks to Pit.
Quote: "Optimist III, by EJS Townsend. The model described here has been developed from a Wakefield machine originally designed at the end of 1939. The Mk.I had a two-wheel, fully retractable undercarriage, a two-bladed folding propeller and was entirety covered with 1/32 sheet balsa. Optimist II had a fixed wire undercarriage and a single bladed folding propeller. The fuselage was double covered with two layers of tissue. From this model the Mk.III was developed, and now a Mk.IV with a single leg retracting undercarriage, single fin and rudder is awaiting flight tests.
Mks I, II and III have all been steady and consistent flyers, Mk.III placing second in the Gutteridge Trophy and fifth in the Weston Cup, also winning many club competitions.
A point worthy of note is that all the marks have been fitted with Mattioli Randisi disruptors which improve lateral stability in gusty weather.
Fuselage: Build up on the plan, both sides simultaneously. This requires care in pin-sticking but gives two identical sides. Longerons and cross-members are 3/32 in substitute, a strong cellulose glue being used for construction. Allow to set overnight before removing from the plan.
Fix the sides together with cross-braces and add the plywood nose former. Add stringers to form a rounded nose-section back to the second cross-brace, The tail and nose sections should be filled in with 1/18 sheet for strength when handling. The tail section is then cut off and a ply of 1/4 in sheet fitted into it, forming a tight fit into the main fuselage structure. The undercarriage and tail skid are then bound and cemented to the fuselage..."
Supplementary file notes
Article
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
-
(oz16250)
Optimist III
by J Townsend
from Aeromodeller
February 1944
44in span
Rubber F/F
clean :)
all formers complete :)
got article :) -
Submitted: 15/07/2025
Filesize: 697KB
Format: • PDFbitmap
Credit*: Pilgrim
Downloads: 137
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
- Optimist III (oz16250)
- Plan File Filesize: 697KB Filename: Optimist_III_oz16250.pdf
- Supplement Filesize: 460KB Filename: Optimist_III_oz16250_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, 2011-2025.
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.