Fun, Learning, Friendship and Mutual Respect START  HERE


Unregistered
Go Back   HeliFreak > R/C Helicopter Support > Scale Helicopters > Power Systems


Power Systems Power Systems Discussion


Reply
 
LinkBack Thread Tools Display Modes
Old 10-05-2016, 02:00 PM   #1 (permalink)
Registered Users
 
Posts: 113
 

Join Date: Jul 2015
Default Motor for 500 Size Apache and 4 blade head

I am working on building an old RC aerodyne 500 size Apache and am having issues trying to find a suitable motor. The kit includes a smaller 120t main gear to allow it to fit in the fuselage, and warns not to use pinions with 12 or less teeth. So, if I want a head speed of 1700 rpm, I need a motor with around 800kv. Does anyone know of a 500 size motor with a KV that low? I have a 1000kv Scorpion and a 1200kv Saxov, and the lowest I can find available is a scorpion 3226 900kv.. Any suggestions?
EnstromPilot is online now        Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Old 10-14-2016, 04:18 PM   #2 (permalink)
Registered Users
 

Join Date: Feb 2005
Default 1000kv motor

I have used a Hyperion 3026 1000kv motor on a Trex 500 which was in an Align Cobra fuselage. I used a 17T pinion giving it an rpm of 1700 for that scale flying speed. It did flew very well for scale. Used 473mm Edge blades on it though I heard 500mm blades would fit, too. Castle Creations Edge 100a was my esc for a governed head speed of 1700.
TACO88 is offline        Reply With Quote Quick reply to this message
Old 10-16-2016, 04:57 AM   #3 (permalink)
Registered Users
 
Posts: 4,228
 

Join Date: Apr 2008
Default

OP

The slowest motor roughly that size I can think of is a XNova 2820-890kV.

http://www.xnovamotors.com/xnova-282...pecifications/

Not ideal as you would need to govern at about 88% with a 13T pinion to get 1700rpm. You would need to watch the ESC temps (especially in Texas).

Taco

I don't know what size main gear that Cobra has, but 1700pm would have seen some fair governing, even with a stock 162T main gear. With the OP's 120T main gear, the ESC would have to govern at 60%, which would probably kill it

RPM = 1000 x 22.2 x 0.9 x 17T / 162T = 2097rpm at 100% towards the end of the flight, so running at 1700rpm would be governing at 81%, which is pretty low for a CC ESC. Does it run hot ?

Colin
__________________
Vario Long Ranger 700e
Seahawk 600
UH-1N 500
Baumann EC-145 800+ (coming soon )
Andy01 is offline        Reply With Quote Quick reply to this message
Old 10-16-2016, 11:38 AM   #4 (permalink)
Registered Users
 
Posts: 579
 

Join Date: Apr 2016
Default

I just got the same fuselage and I'm using the 4 blade head and tail. I went with 3226-900. With a 12t pinion. Where did you see that you can't use a 12?
Bm421 is offline        Reply With Quote Quick reply to this message
Old 10-16-2016, 12:28 PM   #5 (permalink)
Registered Users
 
Posts: 113
Thread Starter Thread Starter
 

Join Date: Jul 2015
Default

Quote:
Originally Posted by Bm421 View Post
I just got the same fuselage and I'm using the 4 blade head and tail. I went with 3226-900. With a 12t pinion. Where did you see that you can't use a 12?
3rd page of the instructions, see attached. As for governing, might oversizing the ESC help with the temps? I was thinking of using a CC edge light 100. Maybe using a beefier Phoenix 100 would help? Otherwise, that motor looks to be the best choice so far.
Attached Thumbnails
Click image for larger version

Name:	image.jpg
Views:	154
Size:	60.3 KB
ID:	675835  

Last edited by EnstromPilot; 10-16-2016 at 01:29 PM..
EnstromPilot is online now        Reply With Quote Quick reply to this message
Old 10-16-2016, 12:39 PM   #6 (permalink)
Registered Users
 
Posts: 579
 

Join Date: Apr 2016
Default

Mine didn't come with instructions and the only one I could find online was in Chinese or Japanese
Bm421 is offline        Reply With Quote Quick reply to this message
Old 10-16-2016, 12:43 PM   #7 (permalink)
Registered Users
 
Posts: 579
 

Join Date: Apr 2016
Default

I'm using a 100amp on mine. I wonder if it is just heat issues or if it's the diameter I flew it with the 12 and if flew fine maybe go up to a 13 to be safe? idk...
Bm421 is offline        Reply With Quote Quick reply to this message
Old 10-17-2016, 04:30 AM   #8 (permalink)
Registered Users
 
Posts: 4,228
 

Join Date: Apr 2008
Default

Personally I would never buy a Edge Lite for a scale heli, unless you fly somewhere that is REALLY cold all year round. The Lite models are designed to have a decent air flow past them, which is something that almost never happens on a scale heli.

I have an Ice 75 in my 500 sized UH-1N, and the ESC is fitted up inside the doghouse and it gets REALLY hot - like around 190-200F when flying circuits in 85F weather. It was better when I had it in the rear cabin with the doors open, but I wanted the cabin clear.

I don't think a Edge 100 will run much cooler than an Edge 75, but I may be wrong. If flying gentle scale-like circuits, you will only be pulling around 20A anyway, so even the 75A is waaay overkill. According to Castle's spec, the Edge 100 is slightly smaller than the Edge 75, although I am not sure that is true.

A CC ESC likes to run between 90-95%, and preferably closer to 95%. I tried one once down to 73% and it got pretty toasty, even with a 80mm computer fan blowing on it. Much better to get a slower motor if you can.

You can also do things to reduce the chances of a gear stripping. Slow spool up (setting 1), reduce the rate of change of speed right down (1 or 2), low governor gain, reduce motor aggressiveness (from ESC) - low timing, medium start power, use DryLube on gears etc, and obviously flying gently. I have no idea if doing these things would allow you to run a 12T pinion, but it may be a good idea with any size pinion.

Colin
__________________
Vario Long Ranger 700e
Seahawk 600
UH-1N 500
Baumann EC-145 800+ (coming soon )
Andy01 is offline        Reply With Quote Quick reply to this message
Old 10-17-2016, 09:20 AM   #9 (permalink)
Registered Users
 

Join Date: Feb 2005
Default Cobra

Taco

I don't know what size main gear that Cobra has, but 1700pm would have seen some fair governing, even with a stock 162T main gear. With the OP's 120T main gear, the ESC would have to govern at 60%, which would probably kill it

RPM = 1000 x 22.2 x 0.9 x 17T / 162T = 2097rpm at 100% towards the end of the flight, so running at 1700rpm would be governing at 81%, which is pretty low for a CC ESC. Does it run hot ?

Colin[/QUOTE]

Colin,

My bad, the pinion on the Cobra was not 17T, I believe it was a 13T pinion. My friend bought the Cobra from me, so I can't double check on the pinion.

Marcus
TACO88 is offline        Reply With Quote Quick reply to this message
Old 10-19-2017, 12:09 AM   #10 (permalink)
Registered Users
 
Posts: 113
Thread Starter Thread Starter
 

Join Date: Jul 2015
Default

Just wanted to update this thread with the results. The Xnova was getting me good headspeed at flat pitch idle, but as soon as I pulled pitch I began loosing headspeed.The small motor just couldn't keep up with lifting a 7 lb model. I have a Scorpion motor on order now: Scorpion HKIII-4020-890KV - Scorpion Power System. Hopefully that resolves the issue, certainly capable of quite a bit more power. Also, I had to switch from my original plan of a Castle Edge 100 to a Talon 90. The Edge was too wide to fit on the side of the frames in the thin fuselage. Here's a photo of the aircraft just before I installed the tail rotor.
Attached Thumbnails
Click image for larger version

Name:	IMG_1467.jpg
Views:	118
Size:	121.5 KB
ID:	726477   Click image for larger version

Name:	IMG_1469.jpg
Views:	122
Size:	69.0 KB
ID:	726478  
__________________
450 Twinrexx HUP Retriever
500 size UH-1C Huey, AH-6 Little Bird, AH-64 Apache, HO3S-1, UH-34D, 3D printed Gazelle
600 size OH-58A Kiowa, SH-3 Sea King
700 AH-1W Super Cobra, MH-60 Blackhawk
EnstromPilot is online now        Reply With Quote Quick reply to this message
Old 10-19-2017, 04:56 AM   #11 (permalink)
Registered Users
 
Posts: 4,228
 

Join Date: Apr 2008
Default

Wow I am surprised you can fit a 50mm diameter motor into a 500 frame - maybe they are special frames. I had to do some filing (cut halfway through a frame spacer bar) to get a 46mm diameter KDE 500XF into my 500.

I am also surprised that a 1100W XNova did not have enough grunt. My 500 sized UH-1N only used around 350W for FF.

Hope it works for you. Keep us posted.

Colin
__________________
Vario Long Ranger 700e
Seahawk 600
UH-1N 500
Baumann EC-145 800+ (coming soon )
Andy01 is offline        Reply With Quote Quick reply to this message
Old 10-19-2017, 07:25 AM   #12 (permalink)
Registered Users
 
Posts: 113
Thread Starter Thread Starter
 

Join Date: Jul 2015
Default

Pasted the wrong link. That was one of the tabs I had open when I was looking at options. This was the one that I purchased: Scorpion HK-3226-900KV - Scorpion Power System. Should fit without any dremeling. But yes, I was also surprised. Hopefully it is the motor that was limiting, and not the ESC. If I need to upgrade there, things would get very difficult..
__________________
450 Twinrexx HUP Retriever
500 size UH-1C Huey, AH-6 Little Bird, AH-64 Apache, HO3S-1, UH-34D, 3D printed Gazelle
600 size OH-58A Kiowa, SH-3 Sea King
700 AH-1W Super Cobra, MH-60 Blackhawk
EnstromPilot is online now        Reply With Quote Quick reply to this message
Old 10-20-2017, 05:07 AM   #13 (permalink)
Registered Users
 
Posts: 4,228
 

Join Date: Apr 2008
Default

I am not sure how ESC could limit it for scale performance - my 500 has a CC Ice 75 and Savox 1300kV motor, flies at 1700rpm, and has plenty of power. My typical logged power was at around 350-400W with occasional sharp spikes up to 650W.

Is there an ESC setting that is de-tuning the system heavily ?

Colin
__________________
Vario Long Ranger 700e
Seahawk 600
UH-1N 500
Baumann EC-145 800+ (coming soon )
Andy01 is offline        Reply With Quote Quick reply to this message
Old 10-20-2017, 11:07 AM   #14 (permalink)
Registered Users
 
Posts: 113
Thread Starter Thread Starter
 

Join Date: Jul 2015
Default

Quote:
Originally Posted by Andy01 View Post
I am not sure how ESC could limit it for scale performance - my 500 has a CC Ice 75 and Savox 1300kV motor, flies at 1700rpm, and has plenty of power. My typical logged power was at around 350-400W with occasional sharp spikes up to 650W.

Is there an ESC setting that is de-tuning the system heavily ?

Colin
Not that I know of. I just know that murphy's law tends to hang around when you have an "non-replaceable" component . My bet is that that the motor resolves it. My 6.5 lb Little Bird flies fine on a 60A ESC and a 1300W motor. The 1700W motor should have no trouble at all. The Xnova, on the other hand was designed to lift a roughly 4 lb 380 size helicopter, and is in a place with little to no cooling. I can see why it struggles a bit to lift 7 lbs of Apache..
__________________
450 Twinrexx HUP Retriever
500 size UH-1C Huey, AH-6 Little Bird, AH-64 Apache, HO3S-1, UH-34D, 3D printed Gazelle
600 size OH-58A Kiowa, SH-3 Sea King
700 AH-1W Super Cobra, MH-60 Blackhawk

Last edited by EnstromPilot; 10-21-2017 at 10:30 AM..
EnstromPilot is online now        Reply With Quote Quick reply to this message
Old 10-21-2017, 04:04 AM   #15 (permalink)
Registered Users
 
Posts: 4,228
 

Join Date: Apr 2008
Default

Bear in mind that the numbers you are quoting is for 3D flying.

A good rule of thumb for scale power is 50W/lb of weight (for 2 blade head), so even 7lbs should only require around 350W for scale FF, about 15-20% more for hovering and around double that to deal with an Oh $hit moment. This is based on gentle scale-like flying - obviously if the flying style gets more aggressive, then additional power is required.

Colin
__________________
Vario Long Ranger 700e
Seahawk 600
UH-1N 500
Baumann EC-145 800+ (coming soon )
Andy01 is offline        Reply With Quote Quick reply to this message
Old 10-25-2017, 10:20 AM   #16 (permalink)
Registered Users
 
Posts: 113
Thread Starter Thread Starter
 

Join Date: Jul 2015
Default

Well, I did technically get it in the air yesterday night, by maybe 3-4 inches. It would appear my predicted head speed was on the low side for maintaining tail rotor authority, even with the 4 blade tail rotor. When I lifted off, it would hold fine through the pull to pitch, but just as the chopper leaves the ground I would run out tail rotor and have to set it back down. I switched to a 14 tooth pinion, which helped a noticeable amount, but I was still bottoming out tail rotor to hold a hover. I will try a higher tooth count pinion to see if I can get things sorted out. Just have to wait on another order now.
__________________
450 Twinrexx HUP Retriever
500 size UH-1C Huey, AH-6 Little Bird, AH-64 Apache, HO3S-1, UH-34D, 3D printed Gazelle
600 size OH-58A Kiowa, SH-3 Sea King
700 AH-1W Super Cobra, MH-60 Blackhawk
EnstromPilot is online now        Reply With Quote Quick reply to this message
Old 10-26-2017, 04:42 AM   #17 (permalink)
Registered Users
 
Posts: 4,228
 

Join Date: Apr 2008
Default

What governor or throttle setting are you running ?

If I am using the correct numbers, you have;

RPM = 900kV x 22.2V x 0.9 x 14T /120T = 2098rpm at 100% throttle towards the end of the flight.

So unless my numbers are wrong, or you are running a very low throttle %, you have PLENTY of speed for the tail (with a 4 blade tail).

I run my UH-1N at 1700rpm, and yes it is only 2x 465mm wide chord blades, and I have 2x 95mm tail blades, but I have not problems with responsiveness on either main or tail rotor. With 2 stock 500 sized tail blades it was pretty marginal at 1700rpm, but with the larger tail blades, it has plenty of tail power.

I would think that you would probably want around 1600-1650rpm on the main rotor, and with 4 decent tail blades (you may have to try larger/wider/longer/asymmetrical tail blades), tail authority should not be a problem based on my experience.

A 4 blade head does generate more torque than a 2 blade, but usually doubling the tail rotor area will easily compensate. Are you getting enough travel (in the important direction) on the tail pitch ? I often don't set my tail pitch slider up so that it is centralised, but rather bias it towards the required direction.

Colin
__________________
Vario Long Ranger 700e
Seahawk 600
UH-1N 500
Baumann EC-145 800+ (coming soon )
Andy01 is offline        Reply With Quote Quick reply to this message
Old 10-27-2017, 12:17 AM   #18 (permalink)
Registered Users
 
Posts: 113
Thread Starter Thread Starter
 

Join Date: Jul 2015
Default

I am governing at 1900rpm at the moment, with the 14T pinion. Lifts off great, no shortage of power, but tail rotor is still bottomed out, running full left stick. I am going to dial in a bit more left bias into the tail and see what I can get.

I am really hoping to stick with my current main blades, which are thin chord swept tip carbon hobby 425mm symmetrical blades. I run them on my 5-blade Little Bird @1650 rpm, and it flies fantastic. It does require 600 size tail blades, but that's to be expected with a 2 blade tail. Asymmetrical is not an option for me since I am running CCW rotation on the mains as well.

My guess is that this is a combination of the CNC helicopter Apache tail unit I'm running (limited tail rotor throws) and the large wake blockage of the vertical fin. That can really do a number on your tail rotor effectiveness. Hopefully some tail bias and (worst case) a bit more head speed can get the tail rotor effective. Otherwise I'll have to try some less scale blades, which would be unfortunate after 10 months of detailing to get it as Scale as possible.
Attached Thumbnails
Click image for larger version

Name:	IMG_1756.jpg
Views:	104
Size:	80.6 KB
ID:	727147  
__________________
450 Twinrexx HUP Retriever
500 size UH-1C Huey, AH-6 Little Bird, AH-64 Apache, HO3S-1, UH-34D, 3D printed Gazelle
600 size OH-58A Kiowa, SH-3 Sea King
700 AH-1W Super Cobra, MH-60 Blackhawk
EnstromPilot is online now        Reply With Quote Quick reply to this message
Old 10-27-2017, 04:58 AM   #19 (permalink)
Registered Users
 
Posts: 4,228
 

Join Date: Apr 2008
Default

You may be able to get some similar length but wider tail blades ?

I had some tail issues with my 600 sized Seahawk because it also has a wide tail section, but I fitted 4x 105mm KBDD plastic blades (painted) and it works a treat - the tail can pull 500W by itself (no mains fitted) and melt a Trex 600 bevel gear in about 30 seconds at full pitch - I did a static test after two tail drive failures.

1900rpm is awfully fast for a 4 blade 500 unless you want to fly it very aggressively. Short flights ?

Colin
__________________
Vario Long Ranger 700e
Seahawk 600
UH-1N 500
Baumann EC-145 800+ (coming soon )
Andy01 is offline        Reply With Quote Quick reply to this message
Old 10-27-2017, 08:47 AM   #20 (permalink)
Registered Users
 
Posts: 113
Thread Starter Thread Starter
 

Join Date: Jul 2015
Default

I may have to try to get a few of the stock Align blades then. Slightly shorter, but wider chord. Or maybe the 72mm rotortech blades. Otherwise I may need to try cutting down some of the 96mm KBDDs. I completely agree with your thoughts on the headspeed, and would rather run a lower RPM as long as I can hold the tail steady. That information on melting the bevel gears is also concerning. Makes me a bit worried about my intermediary gearbox holding up.
__________________
450 Twinrexx HUP Retriever
500 size UH-1C Huey, AH-6 Little Bird, AH-64 Apache, HO3S-1, UH-34D, 3D printed Gazelle
600 size OH-58A Kiowa, SH-3 Sea King
700 AH-1W Super Cobra, MH-60 Blackhawk

Last edited by EnstromPilot; 10-27-2017 at 09:12 AM..
EnstromPilot is online now        Reply With Quote Quick reply to this message
Reply




Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the HeliFreak forums, you must first register.
Please enter your desired user name, your REAL and WORKING email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself. Use a real email address or you will not be granted access to the site. Thank you.
Email Address:
Location
Where do you live? ie: Country, State, City or General Geographic Location please.
Name and Lastname
Enter name and last name here. (This information is not shown to the general public. Optional)
Helicopter #1
Enter Helicopter #1 type and equipment.
Helicopter #2
Enter Helicopter #2 type and equipment.
Helicopter #3
Enter Helicopter #3 type and equipment.
Helicopter #4
Enter Helicopter #4 type and equipment.

Log-in


Thread Tools
Display Modes

Posting Rules
You may post new threads
You may 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
Trackbacks are On
Pingbacks are On
Refbacks are On




Copyright © Website Acquisitions Inc. All rights reserved.
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2021 DragonByte Technologies Ltd.

SEO by vBSEO 3.6.1