Drenalyn 001
Name: Drenalyn 001
Date: August 2012
Material: 3mm #1.3 EPP foam
Wingspan: 13 in.
Airfoil: Flat plate; curved
Propeller: 4 x 2.5 (with 5 degrees down thrust)
Electronics: Hobby King HK1612 brushless motor + 6A ESC + two 1 g Hobby King servos
Battery: Turnigy NanoTech 2S 180 mAh
Weight: 63 g (with battery)
Design:
Quick note about the EPP: I ordered 6mm EPP from RCFoam.com, but I received 6 sheets that were only 3mm thick. Fortunately they re-shipped 6mm EPP, plus I got to keep the 3mm EPP sheets, one of which I used for this airplane.
In 2012, while I was working with the University of Toronto Aeronautics Team (UTAT), we were experimenting with a new type of plane called the "Pizza Box". You start by cutting the planform of the wing from Depron or EPP, and then curve the entire wing. The airfoil is open at the bottom, and this provides a lot of lift, but at the same time, a lot of drag. The purpose of the UTAT airplane we were designing was to have the lightest airplane that can carry the most weight. After conducting my own research, I chose to build a plane that is a combination of the traditional "Pizza Box", "USA UFO" and "The Nutball", which is called the "Drenalyn".
The planform is a 13 inch square with a rounded front. The fuselage's curve was cut and the wing glued in a curved position. The elevons are 2 in. wide, and these are the only control surfaces. The wing's airfoil high point is 3 in. from the LE, and the curvature comes back down after another 4.8 in.
Date: August 2012
Material: 3mm #1.3 EPP foam
Wingspan: 13 in.
Airfoil: Flat plate; curved
Propeller: 4 x 2.5 (with 5 degrees down thrust)
Electronics: Hobby King HK1612 brushless motor + 6A ESC + two 1 g Hobby King servos
Battery: Turnigy NanoTech 2S 180 mAh
Weight: 63 g (with battery)
Design:
Quick note about the EPP: I ordered 6mm EPP from RCFoam.com, but I received 6 sheets that were only 3mm thick. Fortunately they re-shipped 6mm EPP, plus I got to keep the 3mm EPP sheets, one of which I used for this airplane.
In 2012, while I was working with the University of Toronto Aeronautics Team (UTAT), we were experimenting with a new type of plane called the "Pizza Box". You start by cutting the planform of the wing from Depron or EPP, and then curve the entire wing. The airfoil is open at the bottom, and this provides a lot of lift, but at the same time, a lot of drag. The purpose of the UTAT airplane we were designing was to have the lightest airplane that can carry the most weight. After conducting my own research, I chose to build a plane that is a combination of the traditional "Pizza Box", "USA UFO" and "The Nutball", which is called the "Drenalyn".
The planform is a 13 inch square with a rounded front. The fuselage's curve was cut and the wing glued in a curved position. The elevons are 2 in. wide, and these are the only control surfaces. The wing's airfoil high point is 3 in. from the LE, and the curvature comes back down after another 4.8 in.
I used a 1.5 mm x 1000 mm carbon fibre rod ($1.20) to reinforce the wing (at the airfoil high point), the trailing edge, and the fuselage (bottom). I secured the carbon fibre to the EPP using only tape, so I could potentially re-use the carbon fibre.
Flights:
Very little reflex is needed - just 2 mm up on the end of the elevons. This plane is extremely hard to fly since it is fundamentally unstable. However, once I got the hang of it, I could fly very slowly around the field. This airfoil stalls very easily - thus the plane cannot be banked at more than about 20 degrees when turning. Also, since I wanted to make the plane very light (63 g flying weight), I had to use my smallest motor (the HK1612), which unfortunately doesn't have enough power to do a loop-the-loop. After a while, it becomes boring when all you can do is fly around in circles...
The Drenalyn 002 (if I make one) should have a more powerful motor, perhaps one that can use a 3S LiPo, which will allow for more aerobatic flying. Note that if the weight of the plane is increased, the wing area must also be increased in order to keep the wing loading constant.
Very little reflex is needed - just 2 mm up on the end of the elevons. This plane is extremely hard to fly since it is fundamentally unstable. However, once I got the hang of it, I could fly very slowly around the field. This airfoil stalls very easily - thus the plane cannot be banked at more than about 20 degrees when turning. Also, since I wanted to make the plane very light (63 g flying weight), I had to use my smallest motor (the HK1612), which unfortunately doesn't have enough power to do a loop-the-loop. After a while, it becomes boring when all you can do is fly around in circles...
The Drenalyn 002 (if I make one) should have a more powerful motor, perhaps one that can use a 3S LiPo, which will allow for more aerobatic flying. Note that if the weight of the plane is increased, the wing area must also be increased in order to keep the wing loading constant.