Motor/ prop Help needed

[Craigasoarus]

Well I am at it again with my latest build project only to run into the wall I always do because of my ignorance of electrical stuff. I just had Aloft send me a real cool looking motor only to find it wont fit in the nose of the fuselage. The numbers suggested by the kit maker didnt seem to be of help and I now Know that the numbers on the side of the motor have nothing to do with the actual dimensions of the entire unit. So I have a cool motor to look at until I find something to use it in but need a motor for this glider project. I have no idea how to figure out (easily) what my actual motor, esc and prop needs are. My glider project has about 633 sq in. of wing area and will likely be about 800-900 grams empty weight. I have no idea what actual flying weight will be untill it is completed. The motor I received has an outside Dia. of 35mm and my nose is 33mm width and height. I do have a couple of other smaller motors that I bought from Aloft in my inventory (emax 2212 980kv) but not sure if they can provide enough climb for the launches of this glider. Hope you folks dont get tired of me asking for your feedback. Thanks in advance.

 

[Joe Garfield]

So no batteries or props yet? And what motor did you get? The numbers usually mean something just not necessarily outer dimensions.

 

[Joe Garfield]

Here’s a flight call if you want to experiment:

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[Craigasoarus]

So no batteries or props yet? And what motor did you get? The numbers usually mean something just not necessarily outer dimensions.

Thanks Joe for the reply, I have been looking up articles on selecting motors etc. and there is a number of calculations involved I have learned. I understand some of the info like how many watts required per pound for a given model type etc. and now realize that the numbers on the case don't always equal the actual diameter of the motor. I also understand now that lower KV number means more torque and can turn a larger prop etc. Still don't understand how to select the prop diameter etc. and why I need to care about RPM of motor. Bottom line is I still don't know what motor would be good for this project or for the next 4-5 electrics I have kits for. When it comes to batteries I have a couple on hand like 3s and 2s which is what I would prefer to use. I have one kit an e-flight Taylorcraft 450 that at least tell you the size motor but if you dont know about what 450 means you can have a real hard time finding a motor from all that are available. It is frustrating since I would like to be able to know what I need before hand so I can shop for the components I need. Thank you again Joe for taking time to reply.

 

[gp49]

What about starting with the recommended setup from the kit maker, and go from there....

ELECTRONICS SETUP:

Engine: 2836 1120kv
Battery: 2200mha / 3s
ESC: 40A
Propeller: 10X6 (folding)
Spinner 40m
2 Servos 9g (metal)

Vimana | blueskyairmodels

www.blueskyairmodels.com

PROPDRIVE v2 2836 1200KV Brushless Outrunner Motor

PROPDRIVE v2 motors are designed to perform right out of the box with tight windings, smooth bearings, correctly rated magnets, precision cut stator and balanced rotors.

hobbyking.com

 

[Craigasoarus]

What about starting with the recommended setup from the kit maker, and go from there....

ELECTRONICS SETUP:

Engine: 2836 1120kv
Battery: 2200mha / 3s
ESC: 40A
Propeller: 10X6 (folding)
Spinner 40m
2 Servos 9g (metal)

Vimana | blueskyairmodels

www.blueskyairmodels.com

PROPDRIVE v2 2836 1200KV Brushless Outrunner Motor

PROPDRIVE v2 motors are designed to perform right out of the box with tight windings, smooth bearings, correctly rated magnets, precision cut stator and balanced rotors.

hobbyking.com

Thank you GP, Great suggestion and that is kind of what I did, I ordered one from Aloft based on that info but it is to large a diameter for my glider nose area. So I will have to save the motor and esc for another project and am starting over trying to find the correct motor and esc. The motor I purchased said 2826 1090kv but the can diameter is 35mm way to large for my nose area of 30mm max space at the mounting plate. I also need to get up to speed on what all the numbers mean but am not an electrical engineer but only an old worn out Govt Woodworker. In any case I will try to learn as much as I can so I don't have to feel so embarrassed asking on the forum. Although the fellowship with other builders is enjoyable.

 

[Konrad]

There is/are no standards as to outrunner model motor sizing. Some OEM use the size of the stator in their call outs. While not as good as calling out the electrical characteristics of the motor, it does indicate a class of power. Now other OEMs call out the diameter of the can (first 2 numbers) and length (last 2 numbers), this actually tells us little about the motor. But seems to be what novices to electrical power are concerned with. If looking to physically fit the motor comparing weights might be a better reference when looking for the initial fitting of the motor between different OEMs. Try to find a drawing of the motors you are wanting to buy.

 

[Craigasoarus]

Thank you GP, Great suggestion and that is kind of what I did, I ordered one from Aloft based on that info but it is to large a diameter for my glider nose area. So I will have to save the motor and esc for another project and am starting over trying to find the correct motor and esc. The motor I purchased said 2826 1090kv but the can diameter is 35mm way to large for my nose area of 30mm max space at the mounting plate. I also need to get up to speed on what all the numbers mean but am not an electrical engineer but only an old worn out

There is/are no standards as to outrunner model motor sizing. Some OEM use the size of the stator in their call outs. While not as good as calling out the electrical characteristics of the motor, it does indicate a class of power. Now other OEMs call out the diameter of the can (first 2 numbers) and length (last 2 numbers), this actually tells us little about the motor. But seems to be what novices to electrical power are concerned with. If looking to physically fit the motor comparing weights might be a better reference when looking for the initial fitting of the motor between different OEMs. Try to find a drawing of the motors you are wanting to buy.

Thanks Konrad and good to have your input again. (From your former Bay Area, "Oakland" Friend. 1959-1983).

 

[Joe Garfield]

Edit: Wayne's answer below is probably more appropriate.

 

[Wayne]

If you like, @Jarron is very good at defining motor options for planes. He is very good at it and seems to enjoy it. Win win.

Typically there is one critical area for a plane and I will start from that. In this care it it probably the space the motor needs to fit in. Once Ihave the basic motor selected for that goal I then start looking at the prop to get the power I would like from the motor. This will dictate the battery and ASC requirements.

 

[Flying Dutchman]

@Craigasoarus Some very good advice and insight in the above replies, but here is a very simple approach for your situation.

1. You have a hard limit in the diameter that would fit in the 33x33 nose, so look for a motor of 30mm or less diameter.
2. Based on the overall size of the model and the expected 850 gr empty weight, you'll probably end up around 1300 gr total weight (incl. motor & batt).
3. Unless you want to do rocket launches with it, thrust of 125% is enough, so ~1600 gr.

Aloft has some nice motors that would work well even with a 3s battery, like the DualSky 'Electric Glider Motors', in either standard or 'extended shaft' configuration. Especially the latter would be nice, if you're willing to spend a little more.

 

[Craigasoarus]

@Craigasoarus Some very good advice and insight in the above replies, but here is a very simple approach for your situation.

1. You have a hard limit in the diameter that would fit in the 33x33 nose, so look for a motor of 30mm or less diameter.
2. Based on the overall size of the model and the expected 850 gr empty weight, you'll probably end up around 1300 gr total weight (incl. motor & batt).
3. Unless you want to do rocket launches with it, thrust of 125% is enough, so ~1600 gr.

Aloft has some nice motors that would work well even with a 3s battery, like the DualSky 'Electric Glider Motors', in either standard or 'extended shaft' configuration. Especially the latter would be nice, if you're willing to spend a little more.

Thank you Flying dutchman.

 

[Craigasoarus]

I purchased motors and prop spinner etc only to find I need one more part to (prop Adapter) and need to know if the Adapters Aloft sells have the threaded hole in the end (not visible in the photo) for the spinner attachment. Please advise so I can order asap.

 

[Wayne]

What part are you looking at?

 

[Craigasoarus]

Hi Wayne, I am Looking at the prop adapters for the folding prop spinners you sell and I purchased. I need the adapter to attach the spinner and prop to the motor. Thank you and I left a message on your answering machine about same after purchasing an adapter. Thanks again

 

[Craigasoarus]

What part are you looking at?

Wayne I order the adapter that says for fixed prop but it is apparanetly what I need for my attachment photos enclosed. The only thing I cant see is does it have the threaded hole on the end for the prop spinner to attach to.

 

[Craigasoarus]

What part are you looking at?

Wayne, If I ordered the wrong part can you provide the correct one.? and if you dont have a way to attach the prop hub and spinner can you just cancel my order for the adapter. Thanks order number is 102112443. Please advise. thanks

 

[Konrad]

Not Wayne, but just about any Aeronaut collet will have a center spinner thread.

If you are trying to fit that spinner see the collets listed at the bottom of the list. These collets are fitted to the tapered bore of your prop yoke (center section).Pick the one for the shaft size appropriate to the shaft size found on your motor.

30mm Alloy Folding Prop Spinner

We are pleased to offer our alloy folding prop spinners with a great price! Don't confuse these as cheap spinners, these are very nice units with a great price. This Aloft Alloy folding prop spinner has a 30mm diameter and uses a special compact collet. We offer more sizes, but they have a...

alofthobbies.com

If it is a bigger spinner try these.

32mm Alloy Folding Prop Spinner

We are pleased to offer our alloy folding prop spinners with a great price! Don't confuse these as cheap spinners, these are very nice units with a great price. The Aloft Alloy folding prop spinners range from 32 to 45mm in diameter and all share the same collets. We offer more sizes, but they...

alofthobbies.com

Please note that all vendors and suppliers are having supply issue with Covid and shipping so you might have a wait a bit or be real good at mixing and matching non-standard parts.

 

[Craigasoarus]

Hello Konrad, Thanks that is the spinner I purchased and I also purchased another motor that I was able to fit into the fuse of my project. I realized that the base of the spinner needed an adapter to attach it to the motor shaft which I didn't have so I have just made another purchase for the adapter. If it has the center threaded hole then I should be good to go. I did find one in my spare parts bag but it is for a 5mm shaft. I also just plane forgot that I needed that part. Anyway thanks for your help.

 

[Konrad]

Tappers are not standard. So you will want to stay with the same "brand" with the collet as the yoke.

Your spinner has a back plate (Graupner's high RPM spinners often have tappers in the backplate to fit the collets)? Can you give us P/N# and brands as to what you are using.