squishy
Pirate ParkFlyer
I think you got it, you'll know more about it than anyone I know pretty quickly...I just can't figure out the purpose of this direction, what are you trying to achieve besides the max efficiency of a system? Anything?
Thrust vs Power to Weight Ratios for Prop Planes
I think you got it, you'll know more about it than anyone I know pretty quickly...I just can't figure out the purpose of this direction, what are you trying to achieve besides the max efficiency of a system? Anything?
The benefit will be meaningful info on the power system as a whole instead of just motor data and a prop recommendation.
JDConover
Junior Member
Perhaps an exercise in futility. LOL.
Most likely in the long run I will have a feel for what general prop/motor & battery combinations are capable of and save money by just swapping them around on various platforms. I think that is the general idea of the swappable series from FT anyway.
I just wanted to put a bit of science behind it as apposed to just using someone's word for what works. That and the study helps to realize why & what is supposed to happen and why & what actually is happening.
Also, with this same process it would be possible to take the suggested items listed by FT and reverse engineer just for fun.
Bottom Line and to answer your question, Some people read novels, some read technical manuals. I'm one of those people.
alflurin
Junior Member
Thrust to Weight Ratio - Mini SkyHunter overpowered??
Just a fast one. I have a mini SkyHunter and I'm a bit rusty on my by rc skills. I haven't flown in a long time. The original power combo was slightly underpowered to carry 2 2650mAh "nano" Lipos, FPV stuff and other gear. Now I'm afraid it is overpowered but I guess it better to be over than underpowered. I have a Turnigy K-force 40A ESC and a SK3 2836-1500. My thrust to weight ratio is 127.6 W/lbs... is it too much or can I easily control it using my 9XR-pro settings.
Thanks
P.S.: I'm having massive CG problems with this plane. It is insanely tail heavy. I putted two lipos on the front and lead weights, still it is not perfect. Should I cut down a bit of the carbon fiber tubes that connect the tail to the mainframe? Thanks again
Just a fast one. I have a mini SkyHunter and I'm a bit rusty on my by rc skills. I haven't flown in a long time. The original power combo was slightly underpowered to carry 2 2650mAh "nano" Lipos, FPV stuff and other gear. Now I'm afraid it is overpowered but I guess it better to be over than underpowered. I have a Turnigy K-force 40A ESC and a SK3 2836-1500. My thrust to weight ratio is 127.6 W/lbs... is it too much or can I easily control it using my 9XR-pro settings.
Thanks
P.S.: I'm having massive CG problems with this plane. It is insanely tail heavy. I putted two lipos on the front and lead weights, still it is not perfect. Should I cut down a bit of the carbon fiber tubes that connect the tail to the mainframe? Thanks again
Hai-Lee
Old and Bold RC PILOT
Personally my design process for any motor/prop combination starts with the design of the aircraft itself.
Once the size of the craft is decided and the design is roughed out I do a quick estimate of its weight and where the bare airframe will balance.
I then establish what flying performance I will expect and select the motor and battery for the approximate weight requirement to achieve the required CG point and endurance.
Once all of these parameters are established I then sit down and work out what prop will give me the required flying parameters with a reasonable margin of thrust excess, (In case of emergencies).
Props are available in a myriad of diameters and pitches so I select the largest prop diameter that will suit and select the pitch which gives the best thrust/power for my estimated requirement.
After the maiden flight I then evaluate the performance with the prop selected and often swap the prop to see how the flight envelope changes and settle on what i am most happy with.
A motor which has a smaller or lower pitch prop fitted uses less current and runs far cooler plus if I find that I do need more thrust it is far easier for me to change a prop than to swap out an entire Motor/Prop/ESC/Battery combination. An additional bonus is that I often have flight times far in excess of other fliers at the field with similar designs and more reliable aircraft.
Once the size of the craft is decided and the design is roughed out I do a quick estimate of its weight and where the bare airframe will balance.
I then establish what flying performance I will expect and select the motor and battery for the approximate weight requirement to achieve the required CG point and endurance.
Once all of these parameters are established I then sit down and work out what prop will give me the required flying parameters with a reasonable margin of thrust excess, (In case of emergencies).
Props are available in a myriad of diameters and pitches so I select the largest prop diameter that will suit and select the pitch which gives the best thrust/power for my estimated requirement.
After the maiden flight I then evaluate the performance with the prop selected and often swap the prop to see how the flight envelope changes and settle on what i am most happy with.
A motor which has a smaller or lower pitch prop fitted uses less current and runs far cooler plus if I find that I do need more thrust it is far easier for me to change a prop than to swap out an entire Motor/Prop/ESC/Battery combination. An additional bonus is that I often have flight times far in excess of other fliers at the field with similar designs and more reliable aircraft.
