Sikorsky S-43 (oz6320)


Sikorsky S-43 - plan thumbnail image

About this Plan

Sikorsky S-43 (1935) - free flight seaplane for electric power.

Quote: "Several of our builders have requested a Sikorsky, and I thought that the S-43 was a pretty decent looking airplane, so here it is! To fulfill yet another request, this S-43 can be built either as straight free-flight, or as a single-channel R/C model. The folks at Cox Hobbies (John Elliot) were kind enough to furnish us with an evaluation sample of their 'Failsafe' system, and that's the one we designed around. The August 1992 issue of Flying Models magazine reviews this system in an article by Bob Aberte on pg. 50 ff. If you'd prefer to stay with free-flight, leave out the radio stuff, and relocate the batteries to preserve the C.G. (at the wing spars). The Wiring Diagram is explicit for the two versions. I departed from scale in the design in only two areas: the engine nacelles are at 80% of scale diameter to reduce frontal area, and the stabilizer surface area has been increased by about 20%. I also added a door on the port side ...Our model is at a scale of approximately 1:20. As is usual with our designs, we recommend dry-land flying only. Water take-offs can use up a lot of battery power, and a bad water landing can damage motors, batteries, and radio (especially if it's salt water). As much as possible, the model is designed for maximum crash-survivability, with the intent that the wing be able to pivot in the saddle in a hard landing. Accordingly, use the lightest possible rubber bands for initial flight testing, so the wing can shift or detach upon landing. With the tip floats extended, as shown on the plan, it's almost certain that they'll trip up on landing, with the possibility of some damage, so it's suggested that they be installed in the retracted position."

Quote: "Steve, I cut and pasted this plan years ago to make it more economic to enlarge. So there are pieces in the wrong places but it’s all there. Until someone comes up with an original plan, this will have to do. Thanks for putting these on your site as I’d hate to see them lost to future modelers..."

Direct submission to Outerzone.


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

Sikorsky S-43 - completed model photo



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

User comments

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