Very well done! The final motor "test" is done at the flying field: the motor should not get hot. A little warm is OK, but not hot. If the motor runs hot, you must reduce the diameter/pitch of the prop so that the motor turns at a higher RPM and draws less current. This is especially important if you don't know the wattage rating of the motor.
Man you are awesome. All this people online are always trying to make it as complicated as possible which is pointless for a beginner like myself. I be asking simple questions which you have discussed and asnwerd delcuintly in this video, and the answer I always get from people online is "It depends" and they start explaining way too complicated stuff for me which drives me crazy I just want a simple answer! Awesome video thanks!
Hi Simon, I really appreciate this video. Fairly new to RC and have an ambition to start building my own planes. I'm familiar with design principles and techniques re airframe but the power side (electric) is a mystery to me. What you've demonstrated here is a massive help. Thanks!
Simon this is fantastic!!! your level of details is so important in designing your own plane. Absolutely necessary to know abs substantiated with numbers Richard
Looking forward to part 2 how to select what a 400W out runner is! and what prop to choose. Great explanation in simple to follow steps on how to get your output power. Thanks 🙂
I haven't filmed a Part 2, and that information is out there for people to research. A 400w electric motor is one which has the quoted power rating of "400w". My advice would be to choose one with has a slightly higher max power rating. (450w for example) That way you are always within the safe maximum. For prop choice, you need to connect a watt meter to see what is "going on" numerically with the chosen load you have put on your motor.
Nicely presented and very helpful. I think reference should have been made to choosing the right C rating for your Lipo battery and I think also there could have been discussion about prop sizes and which to go for. This last point, along with choosing the best motor KV rating, crucially links to how you want the plane to fly (big draggy slow scale biplane, STOL plane, 3D plane, high speed plane, electric glider etc as each has different needs)
Thanks Mike - Yes I knew when I filmed it I didn't touch on everything. I can expand on this video soon to give more guidance on watt meter use, prop selection and so on. 👍👍
@@SimonWebbRCandModellingChannel You could always do a quick addendum video and link to it in comments. Your overall presentation was very good and helpful so it would add to its value. My particular challenge is converting a 10lb weight 72" span slowish flying Tiger Moth biplane to electric. I probably want a low KV motor driving a big prop (scale diameter suggests 15"). 6S 5000mah lipo I suspect. I'm busy mugging up on what I'll need to be buying!
@@mikeonb4c Yes I will sort something out! At least with your Tiger Moth you have 2 wings to cope with the ballast of 5000mah capacity. I think a low revving low kv motor and a bigger prop would suit the Tiger Moth, and it would behave much more "scale" like in the air. The real aircraft engine wasn't revvy and it plodded about the sky. The model should do the same with sensible electronics selection.
@@SimonWebbRCandModellingChannel Agree! I'm working on it. Id have loved to fly it with the ASP91 FS it came with but its such a pig to start and fuel leaks every that at 72 I've decided nostalgia is getting less and less important. I just want to be flying! 😆👍
Hi, thank you for the Video, it is so informative and inspirational even for those with some experience. It would be ideal to make a spreadsheet with data and formulae using the info you gave for future calculations made easier.........:)
A good intro…… I think you missed mentioning a very important part and that is Pitch Speed. I see a few questions about propeller and KV choice and Pitch Speed must be considered when choosing the motor prop combo. You can have the desired wattage but the model could fly too slowly if the Pitch Speed is insufficient! It’s all about calculating how fast the air speed is coming off the prop.
Yes you are right I haven't mentioned everything. This video gives a background to the basics. I have addressed some things in some replies though. I am considering doing a Part 2 of this video because it has garnered such interest.
Nice video and well explained but just a couple of points. When weighing and calculating the overall weight including all components, and while it won't make much difference, you didn't include the weight of the receiver. However, what I'm trying determine, is how to know the optimal motor, ESC, combination size for the weight of an airframe with only battery, servos, pushrods and landing gear included?
I included a note on not including the Rx.....but I did increase the power of the motor (which more than covers it). Weigh all your components, determine the performance you require, apply P=I x V and work out each one, as I have done. You will get a good idea from doing this.
Great explanation; that sure helps a newbie like me and I will apply it to the 1/9 scale Spitfire I'm beginning. Thank you. One question though, why do you abbreviate the word "cell" with an S ?
That is what the battery companies do!. I asked that question years ago, and never got an answer! The letter "C" is used for the capacity, so maybe they chose the phonetic version "s" for "cell"?!
Thank you for explaining this! Once we add landing gear our kit parts exceed the plane weight. I have wondered about this relationship. What about mixing of brands? Can we pick an esc from company A and a motor from company B? Is this standardized and interchangeable now?
👍👍👍💯💯💯Excellent presentation and without a doubt one of the easiest to follow and use in real life plane set ups.💯💯💯👍👍👍 I AGREE BEST HELP ON UA-cam , THANKS SO MUCH , NEW SUBSCRIBER.
Those values 100w 150w 200w per pound weight of model, were from an article in an RC magazine based on the author's research. I then set about powering the exact same model in each of the 3 power to weight set ups, and was in complete agreement with the author's findings. I should have mentioned this in my video.
You did miss something critical out - Really useful apart from missing the last critical step of finding the correct sized prop i.e. all your components can be correct according to the calculations but if you put too coarser pitch or too bigger prop on you will burn out the esc and or motor. The way I do it (which probably isn't the correct way) is by using the ammeter and running the setup on the bench to make sure that the current is within the rating of the motor and esc if it isn't I fit a finer pitch prop and if that doesn't work drop to a smaller diameter prop. I am sure there must be a better way.
Read the comments because I think somewhere I mention the use of Watt Meters.....the video was to show esc batt and motor only.....an update is needed. Thanks for commenting.
Hi. Glad you enjoyed it. I could make one about servos and servo sizes, but generally I use the rule of get the best you can afford. A nylon geared servo can achieve decent torque but may not last very long. The obvious upgrade is to get a metal geared version. Personally my models have always been "club size" so I haven't actually used larger servos myself, so I feel I am not best qualified to comment about such things. So, in summary get the best servo your budget can afford. 👍
I mention in the video to go online and find a typical item, and get that weight. So for example if you have a mid sized model, choose a mid-sized motor, a mid-sized ESC etc etc...and get those weights online. I have to say that you are very brave designing things like this if you are a newbie....well done!
Where did 175watts per pound come from? Is there some standard of weight to watts? Also how does the size and pitch of the propeller come into play? This vid left me with more questions than answer's..lol
I chose that value as an in between 150w and 200w. You can chose ANY value......but 400W per pound will be a bit ridiculous IMO. There have been magazine articles about it all. Play around with it all and see what suits you best. Less than 100w per pound is a slow model IMO. The propeller size is decided with a Watt meter. You need to link up your new design and open the throttle with various propeller sizes. When you reach 80-90% of your motor's max power output rating then stop. If it exceeds it then you are overloading your motor. So you have to experiment.
@@SimonWebbRCandModellingChannel sorry, wasn't intending to be harsh. The whole concept interests me. I don't have the experience you do so it make sense I would not understand everything. Thank you for the additional information, that will give me something to research more. Is this concept usable for multi-rotor also? I would think it would be from the power/current requirements but would the watts per pound be different due to vertical take off and landing?
@@djmjr77 I don't fly rotors quads or drones so I can't comment on them. Physics won't change but how to select motors and how to monitor loadings and current draw is alien to me where helicopters and their like are concerned. Good luck!
Omg you dont remember where the watt meter, it always goes between the battery and esc. A 45amps is to small and it would be better to be over 20% above 45a
Use a Watt Meter and try different sizes . The load of each prop will draw more or less current, and you will see it in real time on the display, but aim for a steeper pitch with a lower revving motor if you can (usually but depends on the model). Also IC sizes..... so if it is a 40 size model try 10 x 6 etc. It needs experimentation, so you don't overload your motor. I might do another video on that actually. Some design models suit low pitch longer props, others vice versa. Personally I like torquey set ups shifting a lot of air with each revolution, so steeper pitch.
kva tells you the theoretical rpms of the prop per volt of battery. As you add cells the rpm goes up. you could say that battery power goes up with higher kva, but that's not the point of the kva rating on the motor.
![АЛАУДИНОВ у Скабеевой: эти их ВСУ нас НЕ ДОГОНЯТ 😁 [Пародия]](http://i.ytimg.com/vi/an0anqU4WGQ/mqdefault.jpg)
Very well done! The final motor "test" is done at the flying field: the motor should not get hot. A little warm is OK, but not hot. If the motor runs hot, you must reduce the diameter/pitch of the prop so that the motor turns at a higher RPM and draws less current. This is especially important if you don't know the wattage rating of the motor.
Man you are awesome. All this people online are always trying to make it as complicated as possible which is pointless for a beginner like myself. I be asking simple questions which you have discussed and asnwerd delcuintly in this video, and the answer I always get from people online is "It depends" and they start explaining way too complicated stuff for me which drives me crazy I just want a simple answer!
Awesome video thanks!
Hi Simon, I really appreciate this video. Fairly new to RC and have an ambition to start building my own planes. I'm familiar with design principles and techniques re airframe but the power side (electric) is a mystery to me. What you've demonstrated here is a massive help. Thanks!
So glad you found this video helpful. Thanks for your comment! 😊👍
Excellent presentation and without a doubt one of the easiest to follow and use in real life plane set ups.
So glad you enjoyed it and gained knowledge from it Russ 👍 Thanks for your comment!
Simon this is fantastic!!! your level of details is so important in designing your own plane. Absolutely necessary to know abs substantiated with numbers
Richard
Looking forward to part 2 how to select what a 400W out runner is! and what prop to choose.
Great explanation in simple to follow steps on how to get your output power.
Thanks 🙂
I haven't filmed a Part 2, and that information is out there for people to research. A 400w electric motor is one which has the quoted power rating of "400w". My advice would be to choose one with has a slightly higher max power rating. (450w for example) That way you are always within the safe maximum. For prop choice, you need to connect a watt meter to see what is "going on" numerically with the chosen load you have put on your motor.
Nicely presented and very helpful. I think reference should have been made to choosing the right C rating for your Lipo battery and I think also there could have been discussion about prop sizes and which to go for. This last point, along with choosing the best motor KV rating, crucially links to how you want the plane to fly (big draggy slow scale biplane, STOL plane, 3D plane, high speed plane, electric glider etc as each has different needs)
Thanks Mike - Yes I knew when I filmed it I didn't touch on everything. I can expand on this video soon to give more guidance on watt meter use, prop selection and so on. 👍👍
@@SimonWebbRCandModellingChannel You could always do a quick addendum video and link to it in comments. Your overall presentation was very good and helpful so it would add to its value. My particular challenge is converting a 10lb weight 72" span slowish flying Tiger Moth biplane to electric. I probably want a low KV motor driving a big prop (scale diameter suggests 15"). 6S 5000mah lipo I suspect. I'm busy mugging up on what I'll need to be buying!
@@mikeonb4c Yes I will sort something out! At least with your Tiger Moth you have 2 wings to cope with the ballast of 5000mah capacity. I think a low revving low kv motor and a bigger prop would suit the Tiger Moth, and it would behave much more "scale" like in the air. The real aircraft engine wasn't revvy and it plodded about the sky. The model should do the same with sensible electronics selection.
@@SimonWebbRCandModellingChannel Agree! I'm working on it. Id have loved to fly it with the ASP91 FS it came with but its such a pig to start and fuel leaks every that at 72 I've decided nostalgia is getting less and less important. I just want to be flying! 😆👍
Brilliant! As a new kid, you answered a ton of my questions.
Great stuff I am glad you found my video useful 👍
well made, well explained. especially for a beginner who wants to design from ground up. keep up the good work. very appreciated!!!
What a fantastic video, answered the niggling doubts, thank you.
Sorry about the flicker - 4 overhead strip lights and the camera are to blame!
Cool video. The only thing I knew about motor selection was that I don't know anything about motor selection.
Hi, thank you for the Video, it is so informative and inspirational even for those with some experience. It would be ideal to make a spreadsheet with data and formulae using the info you gave for future calculations made easier.........:)
You are very welcome Joseph! 👍
A good intro…… I think you missed mentioning a very important part and that is Pitch Speed. I see a few questions about propeller and KV choice and Pitch Speed must be considered when choosing the motor prop combo. You can have the desired wattage but the model could fly too slowly if the Pitch Speed is insufficient! It’s all about calculating how fast the air speed is coming off the prop.
Yes you are right I haven't mentioned everything. This video gives a background to the basics. I have addressed some things in some replies though. I am considering doing a Part 2 of this video because it has garnered such interest.
Nice video and well explained but just a couple of points.
When weighing and calculating the overall weight including all components, and while it won't make much difference, you didn't include the weight of the receiver.
However, what I'm trying determine, is how to know the optimal motor, ESC, combination size for the weight of an airframe with only battery, servos, pushrods and landing gear included?
I included a note on not including the Rx.....but I did increase the power of the motor (which more than covers it). Weigh all your components, determine the performance you require, apply P=I x V and work out each one, as I have done. You will get a good idea from doing this.
Great explanation; that sure helps a newbie like me and I will apply it to the 1/9 scale Spitfire I'm beginning. Thank you. One question though, why do you abbreviate the word "cell" with an S ?
That is what the battery companies do!. I asked that question years ago, and never got an answer! The letter "C" is used for the capacity, so maybe they chose the phonetic version "s" for "cell"?!
Thank you for explaining this! Once we add landing gear our kit parts exceed the plane weight. I have wondered about this relationship.
What about mixing of brands? Can we pick an esc from company A and a motor from company B? Is this standardized and interchangeable now?
I have never paid attention to brands - I always look at the technical specification of the item I am buying.
I love your accent man
👍😊
Thank you very much.. I'm totally new, understand the units and such but just starting to chew on rc applications and loving it.
👍👍👍💯💯💯Excellent presentation and without a doubt one of the easiest to follow and use in real life plane set ups.💯💯💯👍👍👍 I AGREE BEST HELP ON UA-cam , THANKS SO MUCH , NEW SUBSCRIBER.
Hi Simon really enjoyed your video. So well explained. Thank you.
Thanks so much Alan for taking the time to comment! So glad you enjoyed it 👍
Well done! Keep on RC!
Very well done instructional video. What source did you get the motor watts that you use in the equation(s)?
Those values 100w 150w 200w per pound weight of model, were from an article in an RC magazine based on the author's research. I then set about powering the exact same model in each of the 3 power to weight set ups, and was in complete agreement with the author's findings. I should have mentioned this in my video.
I think so you should add one "okay" counter on the screen 😂😂,but the information is very nice
I am just an amateur at it sorry....but glad you enjoyed the content.
Really informative thankyou
You did miss something critical out - Really useful apart from missing the last critical step of finding the correct sized prop i.e. all your components can be correct according to the calculations but if you put too coarser pitch or too bigger prop on you will burn out the esc and or motor. The way I do it (which probably isn't the correct way) is by using the ammeter and running the setup on the bench to make sure that the current is within the rating of the motor and esc if it isn't I fit a finer pitch prop and if that doesn't work drop to a smaller diameter prop. I am sure there must be a better way.
Read the comments because I think somewhere I mention the use of Watt Meters.....the video was to show esc batt and motor only.....an update is needed. Thanks for commenting.
@@SimonWebbRCandModellingChannel Thank you for producing informative and useful videos.
Excellent video ... although you do need to get out of the fllat spin !!!!!!
Sorry I don't understand your comment - Please expand!
Brilliant sir. Thank you!
Excellent explanation. Thanks
You are very welcome mate!
Very nice friend thank you.
great info. cheers
Hi so this video is so well done, could you make another one about servos and servo sizes please.
Hi. Glad you enjoyed it. I could make one about servos and servo sizes, but generally I use the rule of get the best you can afford. A nylon geared servo can achieve decent torque but may not last very long. The obvious upgrade is to get a metal geared version. Personally my models have always been "club size" so I haven't actually used larger servos myself, so I feel I am not best qualified to comment about such things. So, in summary get the best servo your budget can afford. 👍
@@SimonWebbRCandModellingChannel well said thank you!
That looks like a fun airplane. Are there any plans out there for it?
Not that I know of...I think it is an own design by the builder. It flies really well and is shown in flight in one of my recent videos.
@@SimonWebbRCandModellingChannel - I'll have to find/watch that video. Thanks for the info.
To a newbie I am totally lost on how to decide what components to purchase for my airframe so I can weigh them ????
I mention in the video to go online and find a typical item, and get that weight. So for example if you have a mid sized model, choose a mid-sized motor, a mid-sized ESC etc etc...and get those weights online. I have to say that you are very brave designing things like this if you are a newbie....well done!
Do these theories and formula work for Electric Ducted Fan models as well as propeller?
I am not experienced in flying ducted fan models, but the P = I x V formula will still apply.
As a general rule you will find that ducted fans are less efficient than props, so fans take more power.
Thank you 🎉l
Great JOB !!!!! Thank you very much. Great information.
Where did 175watts per pound come from? Is there some standard of weight to watts? Also how does the size and pitch of the propeller come into play? This vid left me with more questions than answer's..lol
I chose that value as an in between 150w and 200w. You can chose ANY value......but 400W per pound will be a bit ridiculous IMO. There have been magazine articles about it all. Play around with it all and see what suits you best. Less than 100w per pound is a slow model IMO. The propeller size is decided with a Watt meter. You need to link up your new design and open the throttle with various propeller sizes. When you reach 80-90% of your motor's max power output rating then stop. If it exceeds it then you are overloading your motor. So you have to experiment.
If it has confused you then my advice is forget everything I say in the video.......life is too short!.......lol
@@SimonWebbRCandModellingChannel sorry, wasn't intending to be harsh. The whole concept interests me. I don't have the experience you do so it make sense I would not understand everything. Thank you for the additional information, that will give me something to research more.
Is this concept usable for multi-rotor also? I would think it would be from the power/current requirements but would the watts per pound be different due to vertical take off and landing?
@@djmjr77 I don't fly rotors quads or drones so I can't comment on them. Physics won't change but how to select motors and how to monitor loadings and current draw is alien to me where helicopters and their like are concerned. Good luck!
Omg you dont remember where the watt meter, it always goes between the battery and esc. A 45amps is to small and it would be better to be over 20% above 45a
You have misunderstood, I meant I don't remember where the Watt Meter is IN MY WORKSHOP!!!!
Very well explained....Great
What is the right battery for 1400kv motor 40esc?
Well explained, cheers!
Sir have you made the circuit diagram of the ESC
No, I just use standard ESCs suitable for the current I have calculated.
How about the propeller?
Use a Watt Meter and try different sizes . The load of each prop will draw more or less current, and you will see it in real time on the display, but aim for a steeper pitch with a lower revving motor if you can (usually but depends on the model). Also IC sizes..... so if it is a 40 size model try 10 x 6 etc. It needs experimentation, so you don't overload your motor. I might do another video on that actually. Some design models suit low pitch longer props, others vice versa. Personally I like torquey set ups shifting a lot of air with each revolution, so steeper pitch.
what was 2.2 lb in this?
2.2 Ibs in a kilo!
How do you choose the size of the propeller?
Use a Watt Meter! Scroll down as I have answered this already for somebody.
hi, would the power to ratio work for a quad copter
?
This is for fixed wing - I don't fly quadcopters!
Plz give the relation between kva of motor and battery power
Can you be more specific?
kva tells you the theoretical rpms of the prop per volt of battery. As you add cells the rpm goes up. you could say that battery power goes up with higher kva, but that's not the point of the kva rating on the motor.
How is this only 2 servo plane when it has ailerons?
Rudder
Elevator
Ailerons
Isn't that 3 servos?
Oh, I see it. There is no rudder😅
👍❤