# Tail sizing for small aircraft [Drones]

hope you all are having a lovely day.

I am a novice designing a 3D printed, fixed wing drone as a personal project. The mission objective is maximum endurance (and a decent range too). It has a MTOW of 10kg and a wing span of 1m. Reading a few books and internet articles, I've been able to do basic calculations to find these. However, I cannot find any good recources for tail sizing / placement etc.

On a tangential note can somebody experienced in building similar drones summarize the pros and cons of using a pusher vs puller config for the prop in simple words.

Thanks all!

• A good starting point would be to find existing craft of the same class and look at their proportions and sizes. As an aside: 10kg seems rather heavy for a 1m plane - many planes that size weigh barely 500g. For an endurance (efficient) craft, I would try to keep weight below 1kg Jan 22, 2023 at 21:47

Assuming as a 'Strict Datum' your requirements (Mass of 10 Kg and Wing Span of 1 meter), first off we should decide the aircraft configuration.

Since the mass is fairly high, to keep the aircraft simple for a novice pilot, I would use a classic High wing trainer configuration with a Wing Surface of 0.3 Sq.m (30 cm wing chord and 1 m Wing Span). The Stall speed at MTOW=10 Kg is (Assuming a a NACA 4412 Airfoil at Sea Level):

That means: Stall speed 22.027 m/s 79.296 km/h

The Takeoff speed if 1.3 times the Stall Speed: 28.6351 m/s 103.0848 Km/h

Propulsion:

Suggested Brushless Motor Hacker A60-5S V4 28-Pole Kv 295 Power 2600 W

Propeller 18x10.0

Static Thrust 8.724Kg

ESC 120 A

Battery 32300mAh (8s1p)

Endurance about 30 min. Range About 50 Km. Estimated Ready to Fly Empty Mass: 4 Kg. Payload (Camera, LIDAR, Fertilizer, etc.) about 6 Kg (MTOW 10 Kg- RtFEM 4 Kg).

Aircraft plans, you may download it here ( https://freercplans.com/plan3347.search.htm ), scaling the plans for the required dimensions and using the NACA 4412 Airfoil.

Building recommendation:

If the intention is to 3D Print the aircraft, consider to apply carbon fiber and kevlar reinforcements, especially on wing, wing joints, landing gear and wing spars. Due to the high mass, consider to apply wheel brakes to shorten the landing roll.

Takeoff and landing recommendation:

Consider to use at least a 200 mt hard surfaced runway to maximize the takeoff performance.

Tangential note: pros and cons of using a pusher vs puller configuration.

Puller propeller: Pros: Easier aircraft balancing, during Takeoff and landing the propeller gets away from the ground using proper flying technique.

Cons: Propeller airflow disturbing the wing and tail aerodynamics.

Pusher propeller Pros: Clear aerodynamic airflow on wing and tail.

Cons: Aft motor weight needs Center of Gravity proper design, during Takeoff and landing the propeller gets closer to the ground, In case of hand launch the propeller may get too close from the launcher.