The coreless motor in use with a 1s battery has an output of 40-50 grams . Thus, your aircraft with all components and electronic components should have a max. Weigh 50 grams. 
 
 8520 Coreless motor and 138 mm propeller set for models with a total weight of 40 - 50 grams 

 Product features: 
Propeller length: approx. 138 mm
Propeller aperture: 0.8 mm (fixed)
Motor: 8520 motor (8.5 x 20 mm)
Total weight motor and accessories (without propeller): 6.1 grams
Voltage: 3.7 V.
Power: Has enough power for models with a total weight between 40 - 50 grams

 Suitable for our slow flyer models: 
Fokker E.iii
Etrich Taube
Blériot XI
Sopwith Camel
A6M2 Zero
P-51D Mustang
Avro 504k
Humming Bird
Fokker DR.1
SE5A 
 Our engine has excellent performance with low consumption. See for yourself! 
 
 ✅ [PERFECT FOR MODEL BUILDERS] If you are looking for the challenge of getting a slow flyer made of balsa wood to fly, you have found the right accessories here - our RC airplane propeller has a length of 138 mm. 
 
 ✅ [CORELESS MOTOR HAS POWER FOR MODELS BETWEEN 40 - 50 GRAMS TOTAL WEIGHT] Suitable for model aircraft of the Slow Flyer and Park Flyer class up to an aircraft weight between 40 - 50 grams. 
 
 ✅ [PREMIUM SLOW FLYER DRIVE SET AT 3.7 VOLT] The coreless 8520 motor for model aircraft is easy to install and our model builder customers are exceptionally satisfied. 
 
 ✅ [ENGINE + ACCESSORIES WEIGHING NUT 6.1 GRAM] This aircraft model engine KIT is extremely light and has a high-quality copper core with low heat generation.