Wattflyer RC Network: RC Universe :: RCU Magazine :: RCU Forums :: RCU Classifieds :: RCU User Reviews :: RCU YouTube
Home Who's Online Calendar Today's Posts RealTime Post Spy Mark Forums Read
Go Back   WattFlyer RC Electric Flight Forums - Discuss radio control eflight > Electric R/C Airplanes > General Electric Discussions
Register Members List Wattflyer Extras Articles Search Today's Posts Mark Forums Read Social Groups

General Electric Discussions Talk about topics related to e-powered RC flying

Thank you for your support (hide ads)
Reply
 
Thread Tools Display Modes
Old 08-31-2011, 03:34 PM   #1
Doclove524
Member
 
Join Date: Aug 2011
Posts: 66
Thanked 1 Time in 1 Post
iTrader: (0)
Friends: (0)
Default First Electric build questions.....

I have a couple of foam RTFs.. a Cessna, and an MX2 sport plane. I also have a couple of sport planes one is a 63" 4stroke .91, and the other is an Extra 260 70" with a 20cc gasser. This will be my first electric build. I have bought a Senior Telemaster 94" WS. I have all the Tx/Rx stuff as well as the servos to complete the plane. I have questions as to the Motor, ESC, and Bats that I have purchased to go with it. I bought the Gens Ace Mars Brushles BL4850-340KV moter with the BL75A ESC. I also purchased two 5s 3000mah 20c lipos to go with it. I am wondering if this is a suitable combo for this plane, and if there is anything else I will need to complete the package??

Any info is appriciated guys. Like I said this is my first electric "build" and I think I researched before i bought, buy I want some added info as to my set up.

Thanks!!
Doclove524 is offline  
  Reply With Quote
Old 08-31-2011, 06:09 PM   #2
Doclove524
Member
 
Join Date: Aug 2011
Posts: 66
Thanked 1 Time in 1 Post
iTrader: (0)
Friends: (0)
Default

Any info there fellas??? Somebody say something??!!?
Doclove524 is offline  
  Reply With Quote
Old 08-31-2011, 06:35 PM   #3
spad
Member
 
Join Date: Aug 2009
Posts: 643
Thanked 25 Times in 25 Posts
iTrader: (0)
Friends: (0)
Default

All up weight of the airframe?

Amp rating of motor?

Wattage rating of motor?

Are you following any "watts per pound" formula?
spad is offline  
  Reply With Quote
Old 08-31-2011, 06:57 PM   #4
Doclove524
Member
 
Join Date: Aug 2011
Posts: 66
Thanked 1 Time in 1 Post
iTrader: (0)
Friends: (0)
Default

Weight will be in the 9 / 10 lb range. Actually I used what I think is a comprable size or maybe just slightly larger size motor than the hobby lobby website suggests for this plane?? I don't really know all the wattage ratings for these Electric motors. I know that the sugested motor for this plane was a 515KV. And the motor I bought is a 340KV. Sugested motor uses a 55a ESC and the one I got uses a 70A ESC. The motor I bought is 1650W, and I think 75A. They both seem to turn around the same size prop range.

Thanks for your help Spad!!
Doclove524 is offline  
  Reply With Quote
Old 08-31-2011, 07:35 PM   #5
dumo01
dumo01
 
dumo01's Avatar
 
Join Date: Mar 2009
Location: Columbus, Ohio
Posts: 766
Thanked 99 Times in 99 Posts
Club: Westerville Model Aeronautics Assc
iTrader: (0)
Friends: (7)
Default

That motor should give you plenty of power for a 9-10 lb airplane, the spec page I found for it :
http://www.hobbypartz.com/98p-mars-b...75a-combo.html

suggests that motor for model weight up to 15 kg, which would give you marginal performance, but still gives you plenty for 4.5-5 kg.

I would suggest spending time looking through this sticky on selecting electric power systems:

http://www.wattflyer.com/forums/showthread.php?t=18521
dumo01 is offline  
  Reply With Quote
Old 08-31-2011, 08:00 PM   #6
rcers
Community Moderator
 
rcers's Avatar
 
Join Date: Jul 2005
Location: Trophy Club TX
Posts: 6,062
View rcers's Gallery57
Thanked 496 Times in 486 Posts
Awards Showcase

WAA-08 Pilot 
iTrader: (4)
Friends: (9)
Default

You will be fine with that Motor and ESC on the Telemaster. 5s packs is an issue though. The 340kV motor would like 6s voltages as a minimum.

I use a 300 kV motor with 6s but have to spin a 19x8 prop to get 1100 watts or so out of that. The thrust is stunning and speed is fine (for the Telemaster).

With 5s you will have to spin a GIANT prop to get the power up. Not sure you will have that with the standard gear.

Not many 3 blade propellers that might get the watts up a bit.

With 5s voltage you likely wanted to get a 500-600 kv motor. 400 kV = 6s and 300 kV = 8s as a general rule.

Here is a good thread for you to read:
http://www.wattflyer.com/forums/showthread.php?t=60742

Mike
rcers is offline  
  Reply With Quote
Old 08-31-2011, 08:10 PM   #7
Doclove524
Member
 
Join Date: Aug 2011
Posts: 66
Thanked 1 Time in 1 Post
iTrader: (0)
Friends: (0)
Default

Thanks Dumo01! Lots of good info there. So you are saying that the spec on the motor I bought says it will fly a plane weighing 33LB or 15KG!!!!???
Doclove524 is offline  
  Reply With Quote
Old 08-31-2011, 08:16 PM   #8
Doclove524
Member
 
Join Date: Aug 2011
Posts: 66
Thanked 1 Time in 1 Post
iTrader: (0)
Friends: (0)
Default

Originally Posted by rcers View Post
You will be fine with that Motor and ESC on the Telemaster. 5s packs is an issue though. The 340kV motor would like 6s voltages as a minimum.

I use a 300 kV motor with 6s but have to spin a 19x8 prop to get 1100 watts or so out of that. The thrust is stunning and speed is fine (for the Telemaster).

With 5s you will have to spin a GIANT prop to get the power up. Not sure you will have that with the standard gear.

Not many 3 blade propellers that might get the watts up a bit.

With 5s voltage you likely wanted to get a 500-600 kv motor. 400 kV = 6s and 300 kV = 8s as a general rule.

Here is a good thread for you to read:
http://www.wattflyer.com/forums/showthread.php?t=60742

Mike
So are you saying that the 5S bats will not power the motor?? Or will it just not get the most out of what the motor is capable of?? Sounds as though the motor is plenty powerful enough for the plane?
Doclove524 is offline  
  Reply With Quote
Old 08-31-2011, 08:25 PM   #9
Doclove524
Member
 
Join Date: Aug 2011
Posts: 66
Thanked 1 Time in 1 Post
iTrader: (0)
Friends: (0)
Default

Originally Posted by rcers View Post
You will be fine with that Motor and ESC on the Telemaster. 5s packs is an issue though. The 340kV motor would like 6s voltages as a minimum.

I use a 300 kV motor with 6s but have to spin a 19x8 prop to get 1100 watts or so out of that. The thrust is stunning and speed is fine (for the Telemaster).

With 5s you will have to spin a GIANT prop to get the power up. Not sure you will have that with the standard gear.

Not many 3 blade propellers that might get the watts up a bit.

With 5s voltage you likely wanted to get a 500-600 kv motor. 400 kV = 6s and 300 kV = 8s as a general rule.

Here is a good thread for you to read:
http://www.wattflyer.com/forums/showthread.php?t=60742

Mike
Crap... Sound like I blew $50 on two bats that aren't right for my setup??
I can run a 15" or 16" prop on this set up... Will that perform ok and not burn up my setup??
Doclove524 is offline  
  Reply With Quote
Old 08-31-2011, 08:30 PM   #10
dumo01
dumo01
 
dumo01's Avatar
 
Join Date: Mar 2009
Location: Columbus, Ohio
Posts: 766
Thanked 99 Times in 99 Posts
Club: Westerville Model Aeronautics Assc
iTrader: (0)
Friends: (7)
Default

The motor you have will fly a bigger plane than what you have, but only if you pair it up with the right battery and prop. As Mike pointed out, the 5s battery will spin the prop more slowly than a 6s or higher, so you need to use a bigger prop to get the motor to deliver the power it is capable of. This may be a problem depending on how big a prop the Telemaster can use.

Rule of thumb is 50 w/lb will get you off the ground if you are careful, 75 w/lb for a trainer, 100 w/lb for sport, 150 w/lb and up for 3d.

Looks like Mike and I both suggested the same thread as a good place for information

I did a quick and dirty look on Drive calc using a Hacker A50 12L motor (fairly close to your motor), a APC 16 x 10 prop and a 5 s battery puts you around 600 w or so.
A 6s battery would put you close to 950 w, and 8S would put you around 1550 w with a 15 x 10 prop, but it looks like your ESC is maxed out at 6s so that does not help you
dumo01 is offline  
  Reply With Quote
Old 08-31-2011, 08:37 PM   #11
Doclove524
Member
 
Join Date: Aug 2011
Posts: 66
Thanked 1 Time in 1 Post
iTrader: (0)
Friends: (0)
Default

Originally Posted by rcers View Post
You will be fine with that Motor and ESC on the Telemaster. 5s packs is an issue though. The 340kV motor would like 6s voltages as a minimum.

I use a 300 kV motor with 6s but have to spin a 19x8 prop to get 1100 watts or so out of that. The thrust is stunning and speed is fine (for the Telemaster).

With 5s you will have to spin a GIANT prop to get the power up. Not sure you will have that with the standard gear.

Not many 3 blade propellers that might get the watts up a bit.

With 5s voltage you likely wanted to get a 500-600 kv motor. 400 kV = 6s and 300 kV = 8s as a general rule.

Here is a good thread for you to read:
http://www.wattflyer.com/forums/showthread.php?t=60742

Mike
Mike,
In looking at the specs on the motor it states "Input 2-6S (5V - 25.2V)"
So my 5s bats are putting out 18.5V, is that right? I know nothing about this stuff!! Wouldn't the 5S be enough to power the moor at a decent level??

Thanks for all your help!
Doclove524 is offline  
  Reply With Quote
Old 08-31-2011, 08:47 PM   #12
Doclove524
Member
 
Join Date: Aug 2011
Posts: 66
Thanked 1 Time in 1 Post
iTrader: (0)
Friends: (0)
Default

Originally Posted by dumo01 View Post
The motor you have will fly a bigger plane than what you have, but only if you pair it up with the right battery and prop. As Mike pointed out, the 5s battery will spin the prop more slowly than a 6s or higher, so you need to use a bigger prop to get the motor to deliver the power it is capable of. This may be a problem depending on how big a prop the Telemaster can use.

Rule of thumb is 50 w/lb will get you off the ground if you are careful, 75 w/lb for a trainer, 100 w/lb for sport, 150 w/lb and up for 3d.

Looks like Mike and I both suggested the same thread as a good place for information
So is there some chart that would tell me if I use the 5S on a 340KV motor and turn a 16" prop, what kind of wattage I will be producing?? Looks like I will only need 675 - 750 for trainer type flying and 900 - 1000 for sport flying....

Forgive my igroence here guys!! Thaks for your help!
Doclove524 is offline  
  Reply With Quote
Old 08-31-2011, 08:55 PM   #13
rcers
Community Moderator
 
rcers's Avatar
 
Join Date: Jul 2005
Location: Trophy Club TX
Posts: 6,062
View rcers's Gallery57
Thanked 496 Times in 486 Posts
Awards Showcase

WAA-08 Pilot 
iTrader: (4)
Friends: (9)
Default

Originally Posted by Doclove524 View Post
So is there some chart that would tell me if I use the 5S on a 340KV motor and turn a 16" prop, what kind of wattage I will be producing?? Looks like I will only need 675 - 750 for trainer type flying and 900 - 1000 for sport flying....

Forgive my igroence here guys!! Thaks for your help!
To answer above yes the motor will "work" on a 5 cell battery but you will have to spin a large prop to get the power needed.

I would guess with a 16x10 prop you will be around 450 watts. This is about half the power you need.

A 22x10 will be about 1100w - good power for the Telemaster but a HUGE propeller that is likely too big for proper ground clearance.



MIke
rcers is offline  
  Reply With Quote
Old 08-31-2011, 09:04 PM   #14
Doclove524
Member
 
Join Date: Aug 2011
Posts: 66
Thanked 1 Time in 1 Post
iTrader: (0)
Friends: (0)
Default

So I guess my bottom line question is... Will the plane fly on the 5s battery with a 16" prop without damaging the motor or ESC???

Sorry for being a pain here folks!!
Doclove524 is offline  
  Reply With Quote
Old 08-31-2011, 09:08 PM   #15
Doclove524
Member
 
Join Date: Aug 2011
Posts: 66
Thanked 1 Time in 1 Post
iTrader: (0)
Friends: (0)
Default

Originally Posted by rcers View Post
To answer above yes the motor will "work" on a 5 cell battery but you will have to spin a large prop to get the power needed.

I would guess with a 16x10 prop you will be around 450 watts. This is about half the power you need.

A 22x10 will be about 1100w - good power for the Telemaster but a HUGE propeller that is likely too big for proper ground clearance.



MIke
What are your thoughts on using 6S lipo with a 15"-16" prop wattage wise??
Doclove524 is offline  
  Reply With Quote
Old 08-31-2011, 09:57 PM   #16
Doclove524
Member
 
Join Date: Aug 2011
Posts: 66
Thanked 1 Time in 1 Post
iTrader: (0)
Friends: (0)
Default

Ok all!!! I just ordered all this stuff yesterday and I was able to contact the seller and change the motor ESC selection to 98P-Mars-BL4841-550KV-BL60A-Combo. This as you can see is a 550KV motor and a 60A ESC combo. I believe this is right in line with the suggested motor from the hobby Lobby website for this plane. And I hope this will be perfect with the 5S lipos I ordered?? Thoughts from the Gurus???

Thanks for your help!!
Doclove524 is offline  
  Reply With Quote
Old 08-31-2011, 10:18 PM   #17
rcers
Community Moderator
 
rcers's Avatar
 
Join Date: Jul 2005
Location: Trophy Club TX
Posts: 6,062
View rcers's Gallery57
Thanked 496 Times in 486 Posts
Awards Showcase

WAA-08 Pilot 
iTrader: (4)
Friends: (9)
Default

Originally Posted by Doclove524 View Post
What are your thoughts on using 6S lipo with a 15"-16" prop wattage wise??
A 6s setup will likely get you about 600 - 700 watts barely enough to fly the telemaster. Not what you want.
rcers is offline  
  Reply With Quote
Old 08-31-2011, 10:18 PM   #18
rcers
Community Moderator
 
rcers's Avatar
 
Join Date: Jul 2005
Location: Trophy Club TX
Posts: 6,062
View rcers's Gallery57
Thanked 496 Times in 486 Posts
Awards Showcase

WAA-08 Pilot 
iTrader: (4)
Friends: (9)
Default

Originally Posted by Doclove524 View Post
Ok all!!! I just ordered all this stuff yesterday and I was able to contact the seller and change the motor ESC selection to 98P-Mars-BL4841-550KV-BL60A-Combo. This as you can see is a 550KV motor and a 60A ESC combo. I believe this is right in line with the suggested motor from the hobby Lobby website for this plane. And I hope this will be perfect with the 5S lipos I ordered?? Thoughts from the Gurus???

Thanks for your help!!
Much better for 5s.
rcers is offline  
  Reply With Quote
Old 08-31-2011, 10:27 PM   #19
Doclove524
Member
 
Join Date: Aug 2011
Posts: 66
Thanked 1 Time in 1 Post
iTrader: (0)
Friends: (0)
Default

Originally Posted by rcers View Post
Much better for 5s.
Thanks rcers!! And do you think the 550KV motor is plenty for the 9-10lb Telemaster??
Doclove524 is offline  
  Reply With Quote
Old 08-31-2011, 10:33 PM   #20
rcers
Community Moderator
 
rcers's Avatar
 
Join Date: Jul 2005
Location: Trophy Club TX
Posts: 6,062
View rcers's Gallery57
Thanked 496 Times in 486 Posts
Awards Showcase

WAA-08 Pilot 
iTrader: (4)
Friends: (9)
Default

What is the weight of the motor? I ask because sometimes the motor manufactures over estimate their power delivery ability.

I use a formula of a max power output of 3 watts per gram of motor weight. It works pretty well to show what a motor can likely do.

Mike
rcers is offline  
  Reply With Quote
Old 09-01-2011, 02:05 PM   #21
Doclove524
Member
 
Join Date: Aug 2011
Posts: 66
Thanked 1 Time in 1 Post
iTrader: (0)
Friends: (0)
Default

Originally Posted by rcers View Post
What is the weight of the motor? I ask because sometimes the motor manufactures over estimate their power delivery ability.

I use a formula of a max power output of 3 watts per gram of motor weight. It works pretty well to show what a motor can likely do.

Mike
Ok so the motor weight is shown at 295g, and is listed as 1250 Watts.
So your saying it's probably more like 885 watts?? That doesn't seem enough for this plane? Would this motor not be a replacement for about a .60 size nitro motor? It is looking to me like this electric flight is way to involved and confusing to be any fun at this point!!!
Doclove524 is offline  
  Reply With Quote
Old 09-01-2011, 02:11 PM   #22
Doclove524
Member
 
Join Date: Aug 2011
Posts: 66
Thanked 1 Time in 1 Post
iTrader: (0)
Friends: (0)
Default

The recomended motor for this is a 515KV motor. I have seen videos of this plane flying with this motor and it seems like plenty of power. Some take offs I've seen are almost straight up! The plane itself will float around under almost no power and seems to fly nicely with the 515KV motor. So do you guys think the 550KV motor will be plenty to fly the plane with ease??
Doclove524 is offline  
  Reply With Quote
Old 09-01-2011, 02:28 PM   #23
rcers
Community Moderator
 
rcers's Avatar
 
Join Date: Jul 2005
Location: Trophy Club TX
Posts: 6,062
View rcers's Gallery57
Thanked 496 Times in 486 Posts
Awards Showcase

WAA-08 Pilot 
iTrader: (4)
Friends: (9)
Default

Yep that would be my upper safe limit - just under 900w. For a Telemaster that is good power.

Just remember the days when you were new to Nitro - it was confusing to you then. This will all make sense as you learn the new portions of electric flight. Don't be discouraged as questions!

On you motor choice - I am not a big fan of cheapo Chinese motors for larger models. I have had them fail.

So to me I would look at a bit more quality in the motor you select. Sometimes you really do pay for what you get. Reading that other thread I pointed you too has excellent suggestions for a Hacker power system.

I really like the looks of the new OS motors but have not used them. Other higher quality motors are:
  • AXI
  • Motrolfly
  • Hyperion
  • Scorpion
You can trust the ratings on those motors too. Anything with 1100 watts should be just fine.

Mike
rcers is offline  
  Reply With Quote
Old 09-01-2011, 02:46 PM   #24
Doclove524
Member
 
Join Date: Aug 2011
Posts: 66
Thanked 1 Time in 1 Post
iTrader: (0)
Friends: (0)
Default

Originally Posted by rcers View Post
Yep that would be my upper safe limit - just under 900w. For a Telemaster that is good power.

Just remember the days when you were new to Nitro - it was confusing to you then. This will all make sense as you learn the new portions of electric flight. Don't be discouraged as questions!

On you motor choice - I am not a big fan of cheapo Chinese motors for larger models. I have had them fail.

So to me I would look at a bit more quality in the motor you select. Sometimes you really do pay for what you get. Reading that other thread I pointed you too has excellent suggestions for a Hacker power system.

I really like the looks of the new OS motors but have not used them. Other higher quality motors are:
  • AXI
  • Motrolfly
  • Hyperion
  • Scorpion
You can trust the ratings on those motors too. Anything with 1100 watts should be just fine.

Mike
Thanks Mike! Sorry for the slight venting there.... The AXI motor is the suggested motor on the Hobby Lobby Website. But for the size I need we are looking at $159 just for the motor!! Still need a good ESC and Batts!! I have several planes and have been spending way too much on the hobby lately!!! My RFT planes I'm sure have the cheapo motors you speak of and I have had very little problem with them to speak of. I will most likely put together a really nice power package that could be used in my 70" sport plane as well as I get into the electric world a little more..
I really appreciate all your advise and help, I would be lost without the pros!!
Doclove524 is offline  
  Reply With Quote
Old 09-01-2011, 03:41 PM   #25
Doclove524
Member
 
Join Date: Aug 2011
Posts: 66
Thanked 1 Time in 1 Post
iTrader: (0)
Friends: (0)
Default

Originally Posted by rcers View Post
Yep that would be my upper safe limit - just under 900w. For a Telemaster that is good power.

Just remember the days when you were new to Nitro - it was confusing to you then. This will all make sense as you learn the new portions of electric flight. Don't be discouraged as questions!

On you motor choice - I am not a big fan of cheapo Chinese motors for larger models. I have had them fail.

So to me I would look at a bit more quality in the motor you select. Sometimes you really do pay for what you get. Reading that other thread I pointed you too has excellent suggestions for a Hacker power system.

I really like the looks of the new OS motors but have not used them. Other higher quality motors are:
  • AXI
  • Motrolfly
  • Hyperion
  • Scorpion
You can trust the ratings on those motors too. Anything with 1100 watts should be just fine.

Mike
One last bit of info if you do not mind... What would be the suggested prop size for my set up??

Thanks again,
Mark
Doclove524 is offline  
  Reply With Quote
Reply

  WattFlyer RC Electric Flight Forums - Discuss radio control eflight > Electric R/C Airplanes > General Electric Discussions

« Previous Thread | Next Thread »

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Everything You Wanted To Know About Electric Powered Flight AEAJR General Electric Discussions 267 03-26-2014 02:57 PM
$100 Scratch Build Contest "Best Looking" poll here hillbillynamedpossum Scratch and Kit Built Aircraft 107 08-26-2013 11:23 PM
My Eros build for electric.. marksherlock Vintage and old timer models 24 02-14-2012 12:11 PM
new to electric with questions heistheman Power Systems 3 05-03-2011 05:49 PM
New to flying, couple of foamie Build Questions Brown7 Beginners 5 12-16-2010 02:01 PM


All times are GMT +1. The time now is 02:14 AM.


Powered by: vBulletin
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Copyright 2005 WattfFlyer.com
RCU Eflight HQ

Charities we support Select: Yorkie Rescue  ::  Crohn's & Colitis Foundation



Page generated in 0.35598 seconds with 69 queries