About this Plan
Charybdis (aka McCutchen Wing). Free flight single-rotor helicopter-ish contraption.
Quote: "In Greek mythology, Charybdis was an extremely powerful whirlpool off the Sicilian coast. This helicopter is not particularly powerful, but like its namesake, everything revolves at a rather high rate of speed, and to that degree at least the name was appropriately chosen by the inventor, Charles W McCutchen of Princeton, New Jersey.
The Charybdis (oz5275) was developed 18 years ago, while McCutchen was living in Cambridge, England, and caused something of a sensation when he took it to the British Nationals of 1954. Since that time, variations on the 'McCutchen Machine,' as the design is more generally called, have occasionally appeared in European magazines, but a prophet is usually without honor in his own country, and the Charybdis seems to have been completely ignored in the US - a pity, since it is no tougher to build than a good hand-launched glider, and more fun than tying firecrackers to your old flying scales.
Construction is quite simple, with the emphasis on strength. The blade and stabilizer are of sheet rather than built-up, the motor and balance arms are of spruce, and the hub is reinforced with 1/16 in plywood. The motor arm is inlaid into the lower surface of the blade, the reinforcing plate doubleglued over the joint, and the whole bound with silk or other light cloth. This area is then virtually unbreakable, and also a good flat surface for the balance arm to bear against. You can, of course, glue or even bolt the balance arm in place, but Charybdis is much easier to carry around if the arm is detachable.
The blade is simply a 2 ft x 2 in lath of 1/4 in medium sheet balsa, shaped to a constant Clark Y section. No wash-in, no washout, no dihedral breaks; the squarest, easiest wing you ever made. Use a template to maintain section accuracy. Don't try something with under-camber instead. McCutchen tried both under-cambered and curvedsheet airfoils, and found the resulting Charybdis to be unimproved, at best, or just plain unstable, at worst. The stabilizer struts are 1/8 in hard sheet sanded to a streamline section. Use plenty of glue and perhaps even some silk reinforcing at the strut-to-stabilizer joint, the only vulnerable area of Charybdis.
The stabilizer itself is also 1/8 in hard sheet, but is given a lifting section. Be careful to set it at an angle of at least -5° or -6° relative to the blade, as this is most important. The motor pod is so designed mainly because it looks good. The streamlining probably helps a bit, but is really unnecessary. On the other hand, it does provide a solid mass behind the firewall..."
Direct submission to Outerzone.
Supplementary file notes
Plan file includes magazine article.
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
Do you have a photo you'd like to submit for this page? Then email firstname.lastname@example.org
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, 2011-2019.
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.