MD 500 fuse with Trex 500 ESP & Align 4 Blade Head

[DaweMD]

I have a md500 fuse along with the align 4 blade head and was wondering if anyone could point me in the right direction for a good motor and pinion combination? What would be a good headspeed for this head? I have seen some guys talk about scorpion and kde, but was wondering which would be better. I have also heard good things about xnova, but which one of theirs would be good? I am more of a gas and nitro guy so I am a little ignorant when it comes to figuring out electric motors.

Any help would be much appreciated.

[npomeroy]

Are you aware of the formula for head speed?
... rpm (at 100% throttle) = volts x motor kv / gear ratio. Normally reduce the answer by another 10% because motors are not more than 90% efficient. What tooth count do you have on the gear and pinion of the Trex 500? Does it have a motor (what kv?)?
I believe a head speed between 1500 and 2000 rpm is often used for a 4-bladed 500-size.

[DaweMD]

At this point just the head and fuse.

[npomeroy]

OK. So I presume you are going to buy a T-Rex 500 for the mechanics - especially if it's the Align fuselage you have. I think the earlier model 500s have 162-tooth main gear and 12T pinion on a 1600 kv motor. Higher tooth pinions are available. I'd look at a 900 - 1200 kv motor such as Scorpion HK-3226-900KV or X-Nova 3215-930KV.
You could buy mechanics used. Align kits include the motor and you may wish to get a clone bare bones kit so you can chose your own electronics.

[TR450ZS]

A Scorpion motor in a scale fuse? I don't think so......it needs oiling after every 5 flights or so......

[npomeroy]

Originally Posted by TR450ZS

A Scorpion motor in a scale fuse? I don't think so......it needs oiling after every 5 flights or so......

I hadn't thought of that... But on many scale helis with the front off the motor is quite accessible.

[DaweMD]

Ok, thanks guys. I was considering the xnova or one of the Savox motors.

[TR450ZS]

Get yourself a Savox motor you won't be sorry.
I have a 1200kv Savox pro series in my Huey running 1700rpm HS gov and it has plenty of power.
However 1700 IMHO would be to fast for a scale like HS with 4 Blades. I would aim for 1500rpm.
You can download the Mr. Mel's headspead app to assist with your calculations wrt the pinion and gear size etc.

[BlackTitanium]

Originally Posted by TR450ZS

A Scorpion motor in a scale fuse? I don't think so......it needs oiling after every 5 flights or so......

I have Scorpion 1210kv motors, for many years, and oiling the motor is easily accessible in my two 500D scale models.

But since they are no longer available, go with TR450ZS's recommended Savox 1200kv motor.

[DaweMD]

Ok, cool. Thanks again.

[Andy01]

I have a Savox 1300kV motor with CC Ice 75 ESC in my 500 sized UH-1N, running 12T pinion and 162T main gear. I run it at 1700rpm, and the throttling is a bit more than I would like on the 1300kV, so a 1200kV would have been better. It is obviously a 2 blade though, so a 1200kV may even be slightly fast if you plan to run around 1550-1600rpm on it (assuming the gearing is the same).

Colin

[TR450ZS]

Originally Posted by Andy01

I have a Savox 1300kV motor with CC Ice 75 ESC in my 500 sized UH-1N, running 12T pinion and 162T main gear. I run it at 1700rpm, and the throttling is a bit more than I would like on the 1300kV, so a 1200kV would have been better. It is obviously a 2 blade though, so a 1200kV may even be slightly fast if you plan to run around 1550-1600rpm on it (assuming the gearing is the same).

Colin

+1. I was thinking he could use the 1200kv motor and slow the head down with a smaller pinion if possible and in so doing have plenty power and torque available. Can't remember what pinion sizes are available for that main gear.

[Andy01]

I think a 12T was the smallest pinion I could find, but perhaps there is an 11T out there somewhere. Just make sure it is strong enough (enough metal between the tooth root & the hole) - I had a Mod 0.7 12T 6mm pinion shatter (I am not the only one) on a 600 because of this.

Colin

[marke]

i have a question-I have completed my build of my md500 with the 4 bladed head using the stock align 500--and of course i have the 1600 KV motor on it--what happens if i just lower throttle curve-what problem should i expect?

i would like to run around 1500 to 1600 Head speed.. i am running the 164 main with 12 tooth pinion on 1600 kv.. so per the calculator ill need to run at around 59% efficient..which i am sure is bad. i do have a fan on the esc will that help at all? also what about reducing cell count? go higher ma and less cells?

thank you for the help--i assuming a new motor is on the horizon..are scorpion motor bearing that bad that they need to be lubed every 5 flights?

[BlackTitanium]

Originally Posted by marke

i have a question-I have completed my build of my md500 with the 4 bladed head using the stock align 500--and of course i have the 1600 KV motor on it--what happens if i just lower throttle curve-what problem should i expect?

i would like to run around 1500 to 1600 Head speed.. i am running the 164 main with 12 tooth pinion on 1600 kv.. so per the calculator ill need to run at around 59% efficient..which i am sure is bad. i do have a fan on the esc will that help at all? also what about reducing cell count? go higher ma and less cells?

thank you for the help--i assuming a new motor is on the horizon..are scorpion motor bearing that bad that they need to be lubed every 5 flights?

You need an ESC (Kontronik, Scorpion, YGE, YEP) with Active Freewheeling , if you want to run at 59%.

The problem with lowering the head speed, via 59% without Active Freewheeling, is that the motor and ESC will run hotter.
The reason it will run hotter is because lower ESC voltage, to turn the motor, equals higher current draw.

Also, if you run the system at a lower cell count, your power system will just run hotter as well.

Lower voltage = higher current draw = higher ESC & motor temperatures.

You must use a lower KV motor to achieve the desired head speed, and maintain an efficient power system.

[marke]

Originally Posted by BlackTitanium

You need an ESC (Kontronik, Scorpion, YGE, YEP) with Active Freewheeling , if you want to run at 59%.

The problem with lowering the head speed, via 59% without Active Freewheeling, is that the motor and ESC will run hotter.
The reason it will run hotter is because lower ESC voltage, to turn the motor, equals higher current draw.

Also, if you run the system at a lower cell count, your power system will just run hotter as well.

Lower voltage = higher current draw = higher ESC & motor temperatures.

You must use a lower KV motor to achieve the desired head speed, and maintain an efficient power system.

Thank you sort of thought this might be the way forward. Looks like a 960 kv in my future