Witch Hawk (oz4466)

 

Witch Hawk (oz4466) by Jim Clem 1979 - plan thumbnail

About this Plan

Witch Hawk. 1/2A contest free flight model.

Quote: "The hot little 1/2A Gas job that won the 1979 Nats in the hands of Bill Jenkins, and set a new record, too. Witch Hawk, by Jim Clem.

The small 1/2A Witch Hawk (237 square inches of wing area) was designed for the specific purpose of achieving a glide comparable to the larger 1/2A contest ships. This quality, combined with a hot climb, has produced a potent contest machine.

A long tail moment arm was used to place the 27% stabilizer approximately 20 inches from the CG. Had the rudder been placed aft of the stab, the fuselage would have been too long, resulting in the need for a longer nose moment to achieve a proper balance. Consequently, the rudder was placed forward of the stab. This, of course, is nothing new; it's seen all the time, but not too often on AMA gas models. The rudder placement has proven to be a nice arrangement. It is far enough from the prop blast not to be troublesome and it eliminates the need for a lot of left engine thrust. The two degrees used on the prototype was excessive - both Witch Hawks I'm now flying have only about one degree of left thrust. Bill Jenkins' 'hawk' has about the same, or less. During the development stage of testing several models, the rudder was increased slightly in height. The original rudder was found to be 'marginal' since it permitted the airplane to occasionally roll under high power.

The Witch Hawk design has met the original objectives. It can hold its own in the glide department with the larger 1/2A ships; and its fast climb, of course, was never in doubt, The ship also does well without a lot of the wash-ins and wash-outs usually associated with low thrust designs.

The Witch Hawk has gone through a long period of testing and development. A special thanks to Bill Jenkins of Memphis and Jim O'Reilly of Wichita for their help in this development. Jim supplied valuable technical data, while Bill did extensive flight testing with his Witch Hawk. Keith Williams of Bartlesville, Oklahoma, built the first ship and his input was of great value. With help like this, it makes developing a new design much easier.

Construction. If you want to give the Witch Hawk a try, you can do so without a lot of building time. The construction is straightforward and all flying surfaces can be built flat. You can build it very light in weight or you can build it heavy, depending on your local flying conditions; your Witch Hawk can weigh from 5.5 to 7 ounces. If your winds are usually light, build the ship to weigh 5.5 to 6 ounces. If you fly under windy conditions, build a bit heavier for better penetration, you can control the weight by your wood selection.

Wings. Only a few comments need he made about the wings, as the plan is self-explanatory. Keep the outer extremities light by using lightweight balsa for the wing tip panels. Care should be taken when installing the dihedral..."

Steve, Attached is a scan of the WITCH HAWK plan and article that appeared in the December 1979 issue of Model Airplane News.

Direct submission to Outerzone.

Update 05/01/2017: Added missing page of article, article, thanks to Simon Blake.

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

Witch Hawk (oz4466) by Jim Clem 1979 - model pic

Datafile:
  • (oz4466)
    Witch Hawk
    by Jim Clem
    from Model Airplane News
    December 1979 
    42in span
    IC F/F
    clean :)
    all formers complete :)
    got article :)
  • Submitted: 28/05/2013
    Filesize: 292KB
    Format: • PDFbitmap
    Credit*: PI
    Downloads: 2334

Witch Hawk (oz4466) by Jim Clem 1979 - pic 003.jpg
003.jpg

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

User comments

Hi Mary, Steve. I was looking at the article for Jim Clem's Witch Hawk and noticed that page 3 is missing. So, I scanned it in and it is attached. It contains pretty important trimming info for anyone building this model. I have built several, both this size and the 500 version. The Witch Hawk 500 is the model for the One Design event at the 2017 U.S. Nationals.
SimonBlake - 05/01/2017
Add a comment

 

 
 

Download File(s):
 

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, 2011-2024.

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.