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Old May 14, 2011, 10:09 PM
Team Wack-a-Mole
Melnic's Avatar
Maryland
Joined Oct 2008
8,439 Posts
Quote:
Originally Posted by ApexPredator View Post
How about a HS-5245MG?
that is a GReAT cyclic servo but a horrible tail servo.
We just pulled one out of a guys' 500 3 weeks ago and put one of the mini tail servos from value hobby on it and it was great
Here is a budget 500 build
http://www.mycoolheli.com/EXI500BudgetBuild.html

I need to update that page cause some things are outdated
The GY401B is not as good as the Gy48v. The g401Bneeds to be modded.
The SS ESC spings up WAY too fast. The slow start is horrible. Use it if you want buy many have stripped maingears accidently starting it up too fast on a 500. It's easier to get away with it on a 450, but not a 500.
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Old May 14, 2011, 10:45 PM
Maui RC Modelers
United States, HI, Lahaina
Joined Jan 2008
152 Posts
I agree with that tail servo being a bit small for a 500 size heli, and like the description says its more for a 200-450 class helis. I have a full size JR 8900G tail servo on mine.

A 13T pinion with your motor should get you around 2350-2550 HS maybe more depending on your battery's capabilities.
2357 HS @ 20.4v
2565 HS @ 22.2v
2704 HS @ 23.4v

20A - 6.3 minutes 2100mah (70%)
- 6.75 min 2250mah (75%)
- 7.2 min 2400mah (80%)

Useful formulas:
Volts X Kv X .9 X pinion / Main gear = HS
HS X Main gear / pinion / volts /.9 = kv
2.4 (mah used) / 20 (amps) X 60 = Flight time
2.4 (mah used) / 7.2 min (flight time) X 60 = Avg Amps

These are for best estimates only and there a lot of things that will affect your actual numbers. I would start with small flight times and keep track of the mah used and increase times slowly till you get to around 70-75% of your battery's capacity leaving you with some extra mah to play with.

Aloha,
Les
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Old May 14, 2011, 11:40 PM
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Joined May 2011
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Quote:
Originally Posted by Melnic View Post
that is a GReAT cyclic servo but a horrible tail servo.
We just pulled one out of a guys' 500 3 weeks ago and put one of the mini tail servos from value hobby on it and it was great.

Here is a budget 500 build
http://www.mycoolheli.com/EXI500BudgetBuild.html

I need to update that page cause some things are outdated
The GY401B is not as good as the Gy48v. The g401Bneeds to be modded.
The SS ESC spings up WAY too fast. The slow start is horrible. Use it if you want buy many have stripped maingears accidently starting it up too fast on a 500. It's easier to get away with it on a 450, but not a 500.
Thanks for your help. I'm planning on doing the mod on the gy401b. Already ordered the esc so I'll try giving it a go while keeping my fingers crossed. Unfortunately, I also already ordered the micro servo for the tail so I'll have to sell that when I get it from HK.

Can you specify which tail servo you got from value hobby? Could you suggest a servo under the $40 range for my setup?
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Old May 14, 2011, 11:48 PM
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Joined May 2011
16 Posts
Quote:
Originally Posted by MolokaiBoy View Post
I agree with that tail servo being a bit small for a 500 size heli, and like the description says its more for a 200-450 class helis. I have a full size JR 8900G tail servo on mine.

A 13T pinion with your motor should get you around 2350-2550 HS maybe more depending on your battery's capabilities.
2357 HS @ 20.4v
2565 HS @ 22.2v
2704 HS @ 23.4v

20A - 6.3 minutes 2100mah (70%)
- 6.75 min 2250mah (75%)
- 7.2 min 2400mah (80%)

Useful formulas:
Volts X Kv X .9 X pinion / Main gear = HS
HS X Main gear / pinion / volts /.9 = kv
2.4 (mah used) / 20 (amps) X 60 = Flight time
2.4 (mah used) / 7.2 min (flight time) X 60 = Avg Amps

These are for best estimates only and there a lot of things that will affect your actual numbers. I would start with small flight times and keep track of the mah used and increase times slowly till you get to around 70-75% of your battery's capacity leaving you with some extra mah to play with.

Aloha,
Les
This was very helpful, thank you. Saved as reference.
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Old May 15, 2011, 06:15 AM
Older than rocks
n2wizard's Avatar
United States, PA, Warminster
Joined Dec 2002
418 Posts
I have not had good results with the HS-5245. see http://www.rcgroups.com/forums/showthread.php?t=589365

Good moderate priced servo for tail : ES9257 . Google is your friend.

Herman
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Old May 15, 2011, 07:46 AM
Team Wack-a-Mole
Melnic's Avatar
Maryland
Joined Oct 2008
8,439 Posts
http://www.valuehobby.com/product_de...63&item_id=208

We'd recently pulled a 5245 (the guy got it free) from a 500 tail that could not hold w/o wag and put tha servo on. It's pretty good.
http://www.valuehobby.com/product_de...63&item_id=208

Those ES9257 servos are "ok" for the tail but not as good as the value hobby one. I tried one myself and they DEFINITLY were not as good as a futaba S9257
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Old May 15, 2011, 08:04 AM
Registered User
Smyrna, TN
Joined Jan 2005
331 Posts
That servo is a full size and has plenty of torque. But if the speed is a little slow (.15sec @4.8, .12sec @6.0). You really want to look at a servo with a speed less than .1sec if possible. If you are on a budget, this would make a good option.
http://www.valuehobby.com/product_de...21&item_id=208

Dave
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Old May 15, 2011, 01:42 PM
Not a six pack
rocketscience's Avatar
USA, IL, Chicago
Joined Jul 2008
5,268 Posts
I would also warn against using 20C batteries on 6S if you live in a warm climate. I flew mine a few times in 90 degree weather. They were puffy and hot and didn't last long. Shoot for 25C at least. 30C is better but whatever you can afford.
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Old May 15, 2011, 02:24 PM
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Joined May 2011
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I plan on getting some more packs as well, appreciate the advice. I live in a suburb of Chicago and right now it's a cool 41 degrees lol.

I bit the bullet and grabbed that powerhd servo and a 80amp hobbywing esc and separate bec from value hobby today. Looks like I'll be selling off some of my stuff when it comes in.
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Old May 15, 2011, 06:24 PM
Team Wack-a-Mole
Melnic's Avatar
Maryland
Joined Oct 2008
8,439 Posts
back to the work table for my 500.
Maiden flight, 2nd take off after adjusting tracking.
Well, the screw holding the ball link onto the metal arm of the Hitec 5245 servo sheered and then the head wend ape$hit. I know it was the head cause of the way it reacted.
It pitched violently backwards then hit the tail first on the ground. I suspected a head linkage the way it flipped over. Upon inspection I found the sheered screw. It must have become weak on the last crash.

That's the bad thing about metal arms, they don't twist under strain like plastic arms. Same deal with metal gears, the metal does not give and break like plastic gears releasing the force. Blades, all the shafts, boom and belt. I think I have all the parts
I think I'll throw on some junk $8 fiberglass blades for a few flights though :P
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Old May 15, 2011, 08:09 PM
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mij_nagrom88's Avatar
tracy california
Joined Jul 2010
5 Posts
finished exi 500

just thought i would put my build thread up.thanks to rocketscience for all the great info on this bird.my only complaint is the slop in the tail.hopefully the wieghts from heim joint will take care of that.



exi 500 cf version
turnigy 500h typhon motor with 11t pinion
turnigy 80a plush esc with bec
turnigy 930's on ciclic
futaba 401 gyro
futaba 9257 tail servo
turnigy 30c 3000mah 6s battery
exheli 425mm cf blades


all for 400.00. i think this is a great build for a buget person.
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Old May 15, 2011, 10:04 PM
Team Wack-a-Mole
Melnic's Avatar
Maryland
Joined Oct 2008
8,439 Posts
mij,
that heli should be really stable. hope you re-loctited all the metal to metal.

Rocket,
Where do you get that clone belted tail housin
My tail has really taken a beating over the past 2 years. I think I need an upgrade.
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Old May 16, 2011, 06:21 AM
Team Mulikow 3D
Oxfordshire, UK
Joined Jan 2007
4,092 Posts
Quote:
Originally Posted by mij_nagrom88 View Post
just thought i would put my build thread up.thanks to rocketscience for all the great info on this bird.my only complaint is the slop in the tail.hopefully the wieghts from heim joint will take care of that.
Best remove the sticker from the motor before you use it
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Old May 16, 2011, 09:49 AM
Team Wack-a-Mole
Melnic's Avatar
Maryland
Joined Oct 2008
8,439 Posts
My friend tried to take off in his EXI 500. He has a SS ESC and I'd just sold him a spare ESC I had that has a better soft start.
He spooled up and the blades moved too fast and he stripped his maingear.
I tell everyone, that SS ESC does not have a good soft start. Don't buy it. Get a Plush/volcano/hobbywing at the least. Hobbypartz has the 60A opto for $30. I don't see why people think they need to go cheaper.

I have seen reports of the FMT ESC that is inexpensive and it seems to have a soft start that is acceptable.
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Old May 16, 2011, 10:25 AM
Not a six pack
rocketscience's Avatar
USA, IL, Chicago
Joined Jul 2008
5,268 Posts
Quote:
Originally Posted by ApexPredator View Post
I plan on getting some more packs as well, appreciate the advice. I live in a suburb of Chicago and right now it's a cool 41 degrees lol.

I bit the bullet and grabbed that powerhd servo and a 80amp hobbywing esc and separate bec from value hobby today. Looks like I'll be selling off some of my stuff when it comes in.
Well if you're out west by Oak Park or Maywood (I fly right across from Loyola Hospital) let me know and I can help. There's also a bunch of guys on Helifreak who fly out at Schaumburg but that's a bit of a hike for me.
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