Sentry R3 - Design of a Foamboard Scratchbuild

August 2, 2013|Jamblor

Hi Everyone,

This is my first (sucessful) scratchbuild. I call it the Sentry R3. The video below will introduce the plane and the major components and will provide you with an idea of the flight characteristics both onboard and from the ground. Below the video I will post the specifications of the plane and several pictures. I really enjoy this plane as it zips along when the winds are calm and if there is some wind, well I send it straight up and have fun gliding it back down.

I hope you enjoy this plane and I'd love to see people build it for themselves to try out, or modify to make it better! And if you do build one please share the photos or videos.

Thanks and enjoy!

Specifications:

Dollar Tree Foamboard and 1/2" Pink Insulation Foam
-1m (40") Wingspan with a KFM2 airfoil
CG ~ 180mm back from the nose.
AUW: 360g (12.9oz)
Turnigy D2822-14 1450kv
APC 7x4 prop.
20A ESC
1000mAh or 1300mAh lipo
2 x 9g servos
Elevon programming.

Notice the air scoop on the electronics pod. With this design to streamline the electronics, I really needed to direct some aircooling over the esc. Also note that the two tail fins are angled at about 70-80 degrees.

Simple motor mount, thrust line parallel with the foamboard. Also note the carbon fiber spar running along the KF step of the wings.

The underside with two rails to provide strength and hold the servos.

Note the dual control linkages for elevon control on both ailerons and elevators. I tried this design without the ailerons and it has a very hard time banking.

The inside of the electroncs pod.

And finally the plans. These were done in a cad program and then printed full size to pdf. I tested printing them with acrobats tile feater and it printed to scale so hopefully it will work for everyone. If not please let me know so I can fix the plans.

Simply print out the pdf, tape them together and cut out the shapes. Trace onto the foamboard and cut away. The first file is the full plans and the following two are how I cut the shapes out of regular sized dollar store foamboard. (These plans are more cutting plans)