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Book Recommendation

alan0043

Active member
#1
Hi Everyone,

I hope this is the right section on the forum for this question. I would like to find a book on RC motors, props, esc, and more. I understand that there is info on line. But I don't want to get on line every time I want to read something for about 2 minutes. On the FT beginner series Josh talks about the prop choose the motor and the motor choose the esc and etc. How do you know what prop to start with. That is one of the reasons I want to read the info in a book about. Another question that comes to mind, what motor do you put into a plane. Does the wing size have to do with the motor choice ? I understand most of you guys know this info like the back of your hand. I also understand that there is more info then I am asking about that would be nice to see in print. It would be nice to have this kind of info in a book so someone can go to the book as a reference material. Any ideas ?

Al
 

FDS

Well-known member
#2
The best way to do all that easily is to use an online calculator, set up for planes. Theres a load of different ones, I can't remember which one is most often used here, I am sure someone will come along and tell you.
The problem with a book is that it will be out of date in a couple of months, as brushless motors come and go so fast, specs change and suppliers make new versions of existing motors etc etc.
The starting point for all projects is the power:weight, there's simple rules of thumb for performance based on the power in Watts to the weight of the aircraft.
From another post here-
Thanks quorneng. I pulled the following of the internet as a starting point see if you agree.

50-70 watts per pound; Minimum level of power for decent performance, park flyer/slow flyer models
70-90 watts per pound; Trainers and slow flying scale models
90-110 watts per pound; Sport aerobatic and fast flying scale models
110-130 watts per pound; Advanced aerobatic and high-speed models
130-150 watts per pound; Lightly loaded 3D models and ducted fans
150-200+ watts per pound; Unlimited performance 3D and aerobatic models
You pick the sort of flying experience you want, based on the all up weight of the aircraft, which then gives you an idea of how much power you need and what sort of prop you want. For example a pylon racer is going to want a lot of thrust at higher engine RPM's for maximum airspeed, with plenty of power across the top of the throttle, whereas a 3D plane will want more thrust low down in the rev range with plenty of power to weight.
If you want to go fast, you spin a smaller prop faster (broadly speaking) and the bigger the plane the larger the prop diameter will need to be to make the power required.
You look at the motors power output in W and which props are recommended for it, plus where they make peak thrust and efficiency, which is in the motor spec sheet.
You will find that a couple of motors become your go to, I have 3 sizes and RPM's that I use for all my FT builds, most of which are fairly cheap to buy. When you design your own build or come across an airframe you like then you will tend to use a motor and prop combo you are familiar with. Sure if you are racing or competition flying then there's more t it, but I like simplicity, so I stick to motors I know work and that I can get easily, a bit like FT power packs!
 
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alan0043

Active member
#3
The best way to do all that easily is to use an online calculator, set up for planes. Theres a load of different ones, I can't remember which one is most often used here, I am sure someone will come along and tell you.
The problem with a book is that it will be out of date in a couple of months, as brushless motors come and go so fast, specs change and suppliers make new versions of existing motors etc etc.
The starting point for all projects is the power:weight, there's simple rules of thumb for performance based on the power in Watts to the weight of the aircraft.
From another post here-


You pick the sort of flying experience you want, based on the all up weight of the aircraft, which then gives you an idea of how much power you need and what sort of prop you want. For example a pylon racer is going to want a lot of thrust at higher engine RPM's for maximum airspeed, with plenty of power across the top of the throttle, whereas a 3D plane will want more thrust low down in the rev range with plenty of power to weight.
If you want to go fast, you spin a smaller prop faster (broadly speaking) and the bigger the plane the larger the prop diameter will need to be to make the power required.
You look at the motors power output in W and which props are recommended for it, plus where they make peak thrust and efficiency, which is in the motor spec sheet.
You will find that a couple of motors become your go to, I have 3 sizes and RPM's that I use for all my FT builds, most of which are fairly cheap to buy. When you design your own build or come across an airframe you like then you will tend to use a motor and prop combo you are familiar with. Sure if you are racing or competition flying then there's more t it, but I like simplicity, so I stick to motors I know work and that I can get easily, a bit like FT power packs!

Thank you so much for the help. A link to the calculator sounds like it is all I need. I understand about the book. Thank you again for your write up.

Al
 

Merv

Well-known member
#5
Most sellers will suggest a recommended prop. If the seller you are using doesn’t recommend a prop, find someone who does.

If the recommendation is a range, something like 8-10 inches and the voltage is a range, like 2-3s. Use the 10” on 2s and the 8” prop on 3S.
 

alan0043

Active member
#8
James Whomsley from the ProjectAir YouTube channel, who also works for Flite Test, wrote a book called "The Flite Test Book of R/C Planes". I have not read it, but it looks really good. here's a link: https://www.flitetest.com/articles/the-flite-test-book-of-r-c-airplanes-is-out-now
Hi Jackson,

Thank you for the suggestion. I have that book but it does have have the kind of info that I am looking for. I think the info that I am looking for could come down to about 2 or 3 pages. It could even be in the form of a list would be find. Looking for guide lines. It looks like I should buy a scale so I can weigh the air frames. Does wing size have anything to do with motor size ?

Please keep the info coming,
Al
 

Jackson T

Well-known member
#9
Hi Jackson,

Thank you for the suggestion. I have that book but it does have have the kind of info that I am looking for. I think the info that I am looking for could come down to about 2 or 3 pages. It could even be in the form of a list would be find. Looking for guide lines. It looks like I should buy a scale so I can weigh the air frames. Does wing size have anything to do with motor size ?

Please keep the info coming,
Al
Cool! Did you find the book useful? I just use my mum's cooking scales to weigh my airframes. The motor size is based mainly on the weight of the plane and the style. I just finished building a 4m wingspan balsa glider. It weighs 1870 grams, but it flies very nicely off the Turnigy D2836/8 motor on 3s, which is probably just a bit weaker than an FT power pack C. I don't need crazy speed or vertical performance, just a steady climb to altitude, which it does nicely. The same motor flies my FT Simple Scout nicely, which weighs only 700 grams or so and has a wingspan of less than a quarter of my glider. It's less than half the weight with the same power. It all depends on what kind of experience you want from the plane. Good luck with your builds!
 

buzzbomb

I know nothing!
#10
Hi Jackson,

Thank you for the suggestion. I have that book but it does have have the kind of info that I am looking for. I think the info that I am looking for could come down to about 2 or 3 pages. It could even be in the form of a list would be find. Looking for guide lines. It looks like I should buy a scale so I can weigh the air frames. Does wing size have anything to do with motor size ?

Please keep the info coming,
Al
What you need is @mayan and @Mad_Mechanic! Both have posted spread sheets concerning motors and props and batteries and such. It's not so much wing size that dictates motor size. It's the size of the plane, the configuration of the wing, and what kind of flying it's supposed to do.

The reason it's difficult to find in a book, is because it's aeronautics. There is a LOT of calculation that goes into the motor, prop, esc and battery size. The online spreadsheets that my friends will hopefully soon link will help.

You're talking a wing-load calculator, and that gets pretty complicated. That'll just tell you how much force is projected per square inch of the wing. Then you've got to go from there.

We might could help you simplify it. What are you trying to fly?
 

mayan

Well-known member
#11
What you need is @mayan and @Mad_Mechanic! Both have posted spread sheets concerning motors and props and batteries and such. It's not so much wing size that dictates motor size. It's the size of the plane, the configuration of the wing, and what kind of flying it's supposed to do.

The reason it's difficult to find in a book, is because it's aeronautics. There is a LOT of calculation that goes into the motor, prop, esc and battery size. The online spreadsheets that my friends will hopefully soon link will help.

You're talking a wing-load calculator, and that gets pretty complicated. That'll just tell you how much force is projected per square inch of the wing. Then you've got to go from there.

We might could help you simplify it. What are you trying to fly?
https://forum.flitetest.com/index.p...l-the-ft-models-with-electronics-required.64/

There is the link. Like @buzzbomb said let us know what your game plan is. Faster flyer, slow flyer? What is the diameter of the fuselage and the wingspan? High wing, low wing? Weight including everything but battery? Some will ask for weight with battery I prefer it without because battery can most times be changed to help balance on CG point, that way you can use bigger or smaller batteries. If it’s your first build that has no plans for check out my Howard DGA-6 build thread you might learn something out of my understandings. Here is a link to that too.
https://forum.flitetest.com/index.p...d-dga-6-racing-designed-by-mayan.59861/page-5

Good luck!
 

alan0043

Active member
#12
Hi Guys,

Thank you for the links. I some some reading to do now. I am in the rookie stage of learning to fly. A slow flying plane is just find with me. I don't have the stick skills to fly fast yet.

I did like the book by James Whomsley. I think it is a good read before you get a plane or you are thinking about getting into the hobby.

Please keep the info coming,
Al