Espritmodel.com Telemetry Radio
Reply
Thread Tools
Old Jul 19, 2009, 08:41 AM
Chasing dreams not d competion
uk
Joined Feb 2009
573 Posts
Discussion
Medium sized heli best brushless motor and esc choices

Looking at a 4.5 foot long model what options are out there as regards esc and motors?
I see a lot of numbers and other such stuff that means nothing to me, any suggestions?

Dont want stupid priced stuff, i dont want to have to sell the dog to buy them.

Dont want 3d capable things but need powerful to lift weight of scale body shells.

Dont want 2 min flight times, need to have some enjoyment out of them.
BrownOut is offline Find More Posts by BrownOut
Last edited by kananga; Jul 22, 2009 at 01:42 PM.
Reply With Quote
Sign up now
to remove ads between posts
Old Jul 19, 2009, 09:20 AM
Registered User
dswitkin's Avatar
United States, CA, SF
Joined Sep 2007
1,372 Posts
Which heli are you looking at? What size blades do you want to run? What is the expected all-up weight?

Daniel
dswitkin is offline Find More Posts by dswitkin
Reply With Quote
Old Jul 19, 2009, 09:25 AM
Chasing dreams not d competion
uk
Joined Feb 2009
573 Posts
Scratch built, around 1200 ish, around 20oz.

Scratch built mechs.
BrownOut is offline Find More Posts by BrownOut
Reply With Quote
Old Jul 19, 2009, 09:40 AM
Bush Pilots Bounce Higher
Spidious's Avatar
USA, IL, Champaign
Joined Dec 2006
4,309 Posts
Good luck having a coptor with 1200 blades that only weighs 20oz !
Spidious is offline Find More Posts by Spidious
Reply With Quote
Old Jul 19, 2009, 10:03 AM
Registered User
Joined Jun 2009
192 Posts
my trex500esp which slings 425mm blades,with a 2200mah 6s lipo weighs in at 1796grams. that equals to 63.3520 oz.

when you say 1200ish do you mean 1200mm blades or total diameter of the blades? maybe you mean 600mm blades?...

let me know when this heli is built. i sure like to see it.
DrDoom is offline Find More Posts by DrDoom
Reply With Quote
Old Jul 19, 2009, 10:08 AM
Bush Pilots Bounce Higher
Spidious's Avatar
USA, IL, Champaign
Joined Dec 2006
4,309 Posts
He says 5-6 foot long in the title. So that would be about 1200mm long blades.
Spidious is offline Find More Posts by Spidious
Reply With Quote
Old Jul 19, 2009, 10:17 AM
Registered User
Joined Jun 2009
192 Posts
i'm not trying to be a smart a$$ but the OP needs to rethink this over. and what exactly do you mean scratch build??? a frankenstein heli? just imagine if you crash your frankenstein heli, the parts list will drive you crazy.

you have a choice of trex250,450,500,600,700. prices are great right now and they fly and look great.
DrDoom is offline Find More Posts by DrDoom
Reply With Quote
Old Jul 19, 2009, 11:45 AM
Chasing dreams not d competion
uk
Joined Feb 2009
573 Posts
Sorry my mistake, the heli will be 4.5 foot long, the rotor span will be 1220mm, the weight will come in at 20 ounces (570 grams).

I dont need to rethink anything, just some advice on what the better motor and esc combos are out there for this size of model as i dont have any present day experiance in electrics.
Scratch build while ive been in the hobby means bulit from my own design with raw materials made to fit, i am sorry if this means somthing else right now but my model is my design and made by me, the rotor head and tail mechs etc all machined by me, the fuselage all moulded by me etc etc. Frankenstein heli sounds like somthing someone makes up from all the spare parts in their box, i assure you i am a serious modeller and not playing at this ive just been 'out the loop' for a while as i stopped buying the various magazines and am a lone flyer (no club or friends who fly).

As all bits are made by myself getting replacement parts is not an issue and ive not crashed a heli in over 15 years (infact ive actually only crashed once in 26 years if you dont count the piccolo and hornet experimental times which are rubbish helis anyway).
BrownOut is offline Find More Posts by BrownOut
Last edited by kananga; Jul 22, 2009 at 01:43 PM.
Reply With Quote
Old Jul 19, 2009, 12:44 PM
Registered User
dswitkin's Avatar
United States, CA, SF
Joined Sep 2007
1,372 Posts
Hi Kananga,

OK, so you mean 520 or perhaps 550 mm main blades, for a diameter of 1200 mm. That's the same size as a Century Swift 16:

http://www.centuryheli.com/products/...?currentid=304

As you can see, that size heli weighs 1.5 kilograms without the battery. My battery is another 700 grams on top of that, but you could use a smaller pack. It still means you're at 2 kilograms flying weight without the scale fuselage.

I think the lightest you could possibly lift off the ground with a fiberglass scale Apache of this size is 2.5 kilos, and you could easily end up between 3 and 4.

Hope that helps,
Daniel
dswitkin is offline Find More Posts by dswitkin
Reply With Quote
Old Jul 19, 2009, 12:55 PM
Chasing dreams not d competion
uk
Joined Feb 2009
573 Posts
Hi dswitkin, thanks for your replies, here is the approch engineering link http://www.approachengineering.com/products/AP103.php maybe this is the fuse weight and not including the mechs, they reccomend the swift 16 so your spot on.

The mechs of mine are/will be a simple frame that uses the bodyshell as additional strength.
Are there any formulae for how much glassed shells will weigh? i assumed a glass shell wouldbe lighter than the AE wooden one and indeed my own attempts seem to be heavier when made from wood but i can easily be imagineing it ive never had two simular models to compare.

Ive never bothered with weights before, if it flew it flew and that was it but im making these latest models to show what i can do and break into the scale scene with some sort of respect instead of being some gimp making cheque book aircraft so im trying to do everything in the recconised methods.

I apprechiate your reply and do see that i could be off on the weight.

Are there any motor/esc set ups that i could comfortably use for the sort of weight you mention?

I am sorry if i get details wrong, this one is still on paper so can be altered.
BrownOut is offline Find More Posts by BrownOut
Reply With Quote
Old Jul 19, 2009, 01:03 PM
Registered User
Joined Jun 2009
192 Posts
Quote:
Originally Posted by kananga
Hi dswitkin, thanks for your replies, here is the approch engineering link http://www.approachengineering.com/products/AP103.php maybe this is the fuse weight and not including the mechs, they reccomend the swift 16 so your spot on.

The mechs of mine are/will be a simple frame that uses the bodyshell as additional strength.
Are there any formulae for how much glassed shells will weigh? i assumed a glass shell wouldbe lighter than the AE wooden one and indeed my own attempts seem to be heavier when made from wood but i can easily be imagineing it ive never had two simular models to compare.

Ive never bothered with weights before, if it flew it flew and that was it but im making these latest models to show what i can and break into the scale scene with some sort of respect instead of being some gimp making cheque book aircraft so im trying to do everything in the recconised methods.
Dude, that weight (20oz) is for the scale body alone. What about the rest of the heli? electronics, batteries, rotor head and tail . Its common knowledge that a scale model will weigh more.
DrDoom is offline Find More Posts by DrDoom
Reply With Quote
Old Jul 19, 2009, 01:28 PM
Chasing dreams not d competion
uk
Joined Feb 2009
573 Posts
Ok, for arguments sake lets say 700 grams of a simular heli body plus 2000 grams of the mechs plus 100 grams for fun gives 2800 grams auw, any suggestions of a motor and esc combo to lift that weight with 5 x 550 blades?

Common knowledge? i would say its common sence that adding parts makes somthing heavier.

Im not quite sure what the issue is here, this design is in my head/on paper, im making it up as i go along, i cant be expected to know things like finished weight before its even started. Im sorry if ive made a mistake in the numbers im not perfect by any means. I am not a weights and measure steward so i assumed a listed weight of a commercial model was the all up weight.
Ive simply made this thread before i got into the design so i dont waste time and effort designing somthing wrong.
BrownOut is offline Find More Posts by BrownOut
Last edited by kananga; Jul 19, 2009 at 01:39 PM.
Reply With Quote
Old Jul 19, 2009, 01:39 PM
Registered User
Joined Jun 2009
192 Posts
that weight is right up there with the 600 class helis. so motor and esc for say a trex600 would work. a 1000watt brushless motor and 100a esc would work.
DrDoom is offline Find More Posts by DrDoom
Reply With Quote
Old Jul 19, 2009, 01:45 PM
Bush Pilots Bounce Higher
Spidious's Avatar
USA, IL, Champaign
Joined Dec 2006
4,309 Posts
My Agusta A109 Swift 16 weighs in at about 7# 9oz

Just in case you are wondering............ 121oz
Spidious is offline Find More Posts by Spidious
Reply With Quote
Old Jul 19, 2009, 01:45 PM
Chasing dreams not d competion
uk
Joined Feb 2009
573 Posts
Will 100a cope with the start up current of a 5 blade head?

121 ounce is around 3.5 kg, what motor and esc are you using.
BrownOut is offline Find More Posts by BrownOut
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion whats the best brushless motor and esc for a 450 heli jinxboy_2009 Mini Helis 2 Apr 30, 2009 10:22 PM
(another)Whats the best brushless motor and ESC to fit my needs 68Strat Foamies (Kits) 1 Nov 29, 2004 05:09 PM
Best Brushless Motor Controller/ESC Alan72787 Micro Helis 14 Sep 16, 2004 04:37 PM
What is the Best Brushless motor and ESC for my Corona? harbortime Electric Heli Talk 29 Dec 19, 2003 06:39 AM
Best Brushless Motor and ESC for CP Hornet.. Googleplex Micro Helis 15 Feb 14, 2003 08:39 PM