Corkscrew (oz5750)

About this Plan

Corkscrew. Sport aerobatic model for 4 channel RC and .19 - .30 power.

Quote: "The design concept is very basic - use the minimum number of pieces in the right configuration to yield the maximum amount of flyability. Because the piece count is so low, the prototype was completed in less than two weeks - and when it came unglued in flight (read on for details) and self destructed on the way to the ground, the second model was built and flown in only one week's time.

The exposed 'sight gauge" fuel tank may seem odd, but it allows you to land, check your fuel supply and go off again if fuel is sufficient. The simple shaped canopy came from my 'Simple-Fly' design of ten years ago and is extremely functional, as it yields much room inside the fuselage for lots of foam around the receiver and battery pack, and it provides more lateral area for extended knife edge flying.

The large amount of hardwood in the front of the fuselage represents sufficient mass for needed vibration damping for today's high revving engines. With an Enya .19 engine the model is quite docile but it requires about three ounces of nose weight under the engine. With an Enya .29 the model flies great but requires slight tail weight. The best performance has been with a new Super Tigre X-.25 which required neither nose nor tail weight and with an 8 x 4 balanced Master Air Screw prop turning over 16,000 rpm.

Inverted flight is just fine with this model, although tight outside loops are difficult regardless of power used because of the flat bottomed airfoil. The biggest advantage of the airfoil is that its speed envelope is relatively great. Full power yields good speed, but idle power really lets the model slow down for a nice predictable sink rate. Aileron throw must be at least the movement dimension shown on the plans; elevator and rudder throw can be adjusted to suit your temperament, If you elect maximum rudder/elevator movements, you may enjoy learning and performing the below described new maneuvers.

On a paved surface, hold full up and left or right rudder and slowly advance the throttle and watch the model ground spin around and around - I can almost safely get to full throttle - this is a low down Corkscrew.

The model does beautiful flat spins with good recovery if the Center of Gravity is as shown on the plans. The amount of lateral area behind the Center of Gravity is just right for easy entry/exit from this stunt. Climb much higher than you think you need to and enter a tailspin to the left using full left aileron, full left rudder and full up elevator - and full throttle. Slowly move from left aileron to right aileron. Very, very slowly move from up elevator to neutral elevator and the spin will dramatically change from conventional to flat - and then continue moving the elevator to full down position and the rate of descent will slow considerably - a beautiful, graceful and dramatic stunt! Recovery will take 2-3-4 rotations after neutralizing all controls if full power is left on. If you reduce the power or the engine quits, it may flat spin all the way to the ground! The prop blast on the fin/rudder is required to recover from the flat spin safely and quickly.

Sideslips are a breeze. Set your throttle one click above full idle, put in full right rudder and gently and carefully add left aileron as will be required to keep the left wing down and forward. You will also have to add slight amounts of up elevator - be sure to straighten up before touchdown, 'cuz you can't land sideways without dinging up wingtips! A fun and realistic stunt.

Corkscrew will knife-edge nicely with a .25 - .29 eng. From level flight bring up the nose slightly, a roll to the right or left and opposite rudder is applied. If the model flies to the top side, add slight weight to the tail and decrease/lower the elevators a turn or two on the clevis. If it knife-edges to its bottom side, do just the opposite..."

Quote: "Dear Steve, I love your website! Keep up the great work!! I just stumbled upon it the other day! I have attached for you a set of plans for an RCM magazine build called the Corkscrew by Stu Richmond. It was published in the January 1983 edition of RCM. Attached is a scanned set of plans original size. Also attached is the original article from RCM Jan 1983 written by Stu Richmond. Please post to your website. I bought these plans in 1983 when the magazine came out! I started building this plane in 2007 and the project has been on hold for the last 7 years, I'm getting ready to finish. I started a build thread on RC Universe's website back in November 2007
http://www.rcuniverse.com/forum/scratch-building-aircraft-design-3d-cad-174/6573923-rcm-plans-corkscrew.html#post6573923 It sparked some interest in the little plane and a few guys started building it across the U.S.. As of last year these plans are no longer available and as far as I know the only two people with the plans and the article are now you and I. If you get it published I will post the link to your site on the RCUniverse thread I started. Thank you and keep up the great work!! Sincerely,"

Direct submission to Outerzone.

Supplementary file notes

Article pages, text and pics.

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