I completed the maiden flight of my Ranger EX 757-3 today, with mixed results. The flying weight today was 6lbs, using a standard rule of thumb, the power requirements would be 450 - 600W. The supplied 3715/1000KV outrunner brushless motor only provides 300W.
- Initial parameter selection flew the aircraft safely and successfully in Manual and FBWA!
- The build was good (no bits flew off)!
- All the systems checked out
- Power monitor
- LIDARlite V3
- Airspeed sensor
- Modes checked
- Manual - now have a good trim
- Under powered, with the current motor and 6lbs flying weight takeoff and climb out were sluggish
- Batteries 2 x 5100mah 3S 8C batteries in parallel - which should deliver 40A each
- 40A ESC
- 25A motor (~300W)
- Looking to upgraded the motor to 450W plus and may need 60A ESC for 600W motor
dear Marc Halcomb would you please help me on something i wanna find telemetry madule
and i have holybro 500 Mw i want to know is it good for ranger or not?i saw ppl used 3DR and X8R,
I did both, I changed the motor first (E-flite Power 15) and flew with a 3S power pack, the performance was better but not great. Then I changed from 3S 5100mah to 4S 5500mah and the performance is good, lots of power to climb and at 8-10A cruise I get 30min from one 5500mah battery.
Takeoff weight of my 757-3 = 2700g
Original Motor 3S battery: 20A full throttle 950g static thrust (10X5 prop)
E-flite Motor 3S battery: 22A full throttle 1325g static thrust (10X7 prop)
E-flite Motor 4S battery: 33A full throttle 2150g static thrust (10X6 prop)
E-flite Motor 4S battery: 30A full throttle 1900g static thrust (10X5 prop)
The 10X6 prop runs the motor near the motors recommend maximum, but I only use full throttle for takeoff and have not encountered any thermal issues (yet). I did not go back and try the original motor with the 4S battery, that may be more than enough to get good performance from the airframe!
Second flight E-flite motor 3S battery: https://youtu.be/UFxnw4ubSEs
third flight E-flite motor 4S battery: https://youtu.be/J7a-_8eF0wY
Can you send me a link to the video? I cant seem to find it. Also did you switch to motor or just upgrade to 4s?
I just posted and update from my 3rd flight (with video clip of takeoff/landing), switching to a 4S power pack with the new motor have solved the underpowered problem!
Make sure you post some videos so i can see what a good flying ranger looks like. I'm one click from buying this replacement motor. I just don't know if 3s will work.
Thanks for the input Ben. After much searching, and some simulation I am switching to 4S batteries. A static thrust test using 3s batteries and various propeller pitches produced results in the 1375g range for a 2700g aircraft. The 4S batteries produced 2350g of static thrust. I plan to fly again soon, the local weather has been wet, so maybe a week or so before the 3rd flight. I hope to get much of the tuning complete on the next outing.
I tried stability takeoff with the higher max throttle and it worked well. I don't think I have enough stick time to use the word usually. I mainly keep it in stability to ensure when it crashes it crashes gear down. Because of the under powered motor I never have ventured to the fbwa, b, rth, loiter or any other mode where I surrender throttle control.
Ben, besides the "stable mode" takeoff attempt with the 75% throttle limit, do you usually use one of the stability modes for takeoff? eg FBWA, FBWB, STABILIZE ...
I was finally able to complete the 2nd flight of my Ranger EX 757-3. My expectations were high, the results were less than impressive. After installation of a 450W motor, I expected to the current in the 40A range (Burst) for takeoff, followed by 34A (Continuous) at full throttle. I expected a considerable boost in performance from the maiden flight, but as you can see I am running at 25A full throttle, and from the right-hand plot only 12A in FBWA.
As a result, I only had slightly better performance for the 2nd flight. Fortunately, my dodgy takeoff was followed by very stable albeit underpowered FBWA circuits around the field, followed by a nice landing.