Watt Four (oz13084)
About this Plan
Watt Four. Radio control sport aerobatic model, for 40 - 60 engines.
Note this is a clone of the Chris Foss Wot 4 design. The original design used a foam wing, this here shows a built-up wing. Note the plan shows choice of two wings, either straight-chord or tapered.
Note this plan was previously available as a free download, from the now-defunct Colin Usher website. We found this file in 2021 using the Wayback machine, see datafile link.
Quote: "Watt Four Notes: The original [Wot 4] design has been at the top of the best selling list of model kits for years and an ARTF version was released some while ago. This has now been followed by an Electric RTF 'Foamie'. It is a simple model but it has a sparkling performance and is a superb follow on from a basic trainer. A plan has never been released, so it is impossible to build your own exact copy from scratch. Building a near copy is not as easy as it seems, every version from the Mk I to the latest Electric Foamie is different.
I have built a number over the years from so called 'official plans' to drawings made from crashed models or from parts copied from a kit prior to assemble. They all look the same but vary considerably in detail. For example the chord on the ARTF is 11 in although the span is the same, but the MK II has a 12 in chord. The Foamie is only 47.5 in span and the XL (Extra Large) is 68 in.
Fuselage shapes also vary considerably, as does the hinge line for the rudder, vertical on the ARTF, sloping on the MK II. Then we have the Taper Wing version with a slightly larger span, and so it goes on.
The drawings given here are in pdf format and for copyright reasons not an exact copy of the original, whatever that may be. For a start the wing is built up construction (now copied by the new ARTF version) and the airfoil is not as per original. This is an NACA 63 0 18 Root & 63 0 15 Tip. Other minor changes make it slightly different.
Electric Version hence the Watt Four: The plan as drawn is for an OS 46 MAX FX but a version is flying with an AXI 4120/14 660 kv Brushless motor, a JETI 70w Advanced SB ESP, together with a Winforce 5 cell Li-Po pack running a 12 x 8 prop. Cheaper alternatives are a KSM 4120/06 660kv with a Wasp 70W Opto ESP from BRC. A 4 cell Li-Po also works but without the extra power of a 5 cell.
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
by Colin Usher
Found online 15/05/2021 at:
Format: • PDFbitmap
Do you have a photo you'd like to submit for this page? Then email email@example.com
User commentsNo comments yet for this plan. Got something to say about this one?
Add a comment
* 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.
© Outerzone, 2011-2021.
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.