450 Derek's Trex 450 Pro DFC

cml001

cml001

Well-Known Member
So what is my head speed? Align 450mx 3400kv, 12t pinion, 121t main gear, 106t auto gear, & 25t tail drive gear... Using a 3s 45c 2250mah pk... Train ratio is 1:10.08:4.24

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What # does peak efficiency come from on mr Mel's calculator? How does it know the amount of stick/throttle?

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View attachment 11006View attachment 11007
 
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Slobberdog

Slobberdog

Well-Known Member
I done it a little earlier and I think it came out at 3900 ish starting and finishing the flight at about 3300 ish

It does not know the stick throttle position it assumes you are running a flat 100% curve, and the efficiency is hard to get spot on so that is why it's set at 90%, the older your gear the less efficient it probably be!
 
Derek

Derek

Well-Known Member
cml001 said:
Just checked... 95-90-85-90-95 throttle curve on idle up... 13 pitch pos & neg.. My cyclic is at 9 degrees... Now I use the AR7200... Ur on the 3GX right.. I don't know if there are any differences between the 2 gyros w my numbers... I'm pleased with them tho... Hope that helps.

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U could look at my flight in the video section and compare the sound.... U said urs was screaming... That was in a 45c pk as well
Click to expand...

I'm using the Yep 45 amp esc. The head has +/- 10 degrees of pitch with 8 degrees of cyclic and yes, I'm using the 3GX on this one. I did buy two new 45C Nano Techs that I will be using when I get the connectors soldered on.

pvolcko said:
I got ~4050RPM for your high headspeed. 3600 * (3 * 4.2) * .9 * (12/121) Not sure why my number and the Mr. Mel number is so different. And that's only considering motor efficiency. You'll have mechanical losses in the drivetrain too, losses due to torque, etc.

It is high, though. 2800-3600 seems to be the range people fly at in my short research effort.

11T pinion would get you down to 3700ish RPM.
Click to expand...

I will be hunting down an 11 tooth pinion. I suppose I could just modify my throttle curve so that the high stick is only 80% (for example) or something like that.

Slobberdog said:
Derek what motor you running cos the Align 450mx is 3400 kv, not sure how much diff that will make though
Click to expand...

I'm using this motor - Turnigy HeliDrive SK3 Competition Series - 2839-3600kv (450 size heli)
 
Derek

Derek

Well-Known Member
No further thoughts or opinions?

Well, I did make it out the hobby shop today and they had an 11 tooth helical pinion, so I grabbed it. I'll try to get that installed tonight.
 
Ken Jackson

Ken Jackson

Active Member
You'll like those nano tech 45c batteries. The price is good and they perform very well. I bought them for my 500 last year and grabbed a pair for my 450 this winter.
Ken
 
Derek

Derek

Well-Known Member
I just noticed something on my 450 that made me shut it down...again.

I have the Yep 45amp esc on my 450 and when it is powered on, there is a little red light that is on. Ok...fair enough. The issue is when I spin the 450 up, above 50%, the little red light dims and then is off completely until I lower the throttle back down. Then the light on the Yep illuminates again.

Any thoughts? is this normal?
 
Derek

Derek

Well-Known Member
Ok, picture this...I have my DX8 turned on and Throttle Hold active....the 450 is plugged in and the 3GX is initialized.

Now...when I give rudder input, either right or left, the tail will come back to center when I let go of the stick. Does this mean that I am in Rate Mode? I need to be sure that I am in Heading Hold Mode.
 
murankar

murankar

Staff member
That should be rate mode. In head hold the slider won't move after giving input while on the bench. In the air it will correct instantly until it hits the correct heading.

Sent from my LG-E980 using Forum Runner
 
Derek

Derek

Well-Known Member
yeah, that's what I thought, too, Matthias. Hmmm, I don't want to be in Rate Mode. I must have missed something in the setup.

Thanks for the reply.
 
Derek

Derek

Well-Known Member
Thanks Kev! I have been going over the PDF manual that I downloaded and it said the same thing. The green status light is to indicate Heading Hold Mode. On my 3GX, the status light is indeed green, but the tail acts like Rate Mode.
 
Slobberdog

Slobberdog

Well-Known Member
Is your tail servo reversed, one of the guys in my club has his reversed and the HH mode is then -45 per say
 
Derek

Derek

Well-Known Member
not sure if the tail servo is reversed. During the bench tests, the tail turns, functions, and compensates correctly. Should I try setting the gain to a negative value and see hat happens or should I reverse the tail servo and redo the DIR?
 
Slobberdog

Slobberdog

Well-Known Member
Tbh you have the correct light so I am not sure,

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Derek just tried mine and in HH it returns to pretty much centre as well
 
Derek

Derek

Well-Known Member
Thanks Kev! I was just thinking about something, so I started messing with the 450 again. With the Status light being red, Rate mode, I moved the tail of the helicopter from the left to the right....the tail blades don't move, so it's not trying to correct for the movement. I changed the gyro gain back to the suggested 35%, this makes the Status light back to green, Heading Hold mode, I moved the tail of the helicopter from the left to the right...the tail blades move to make the compensation but don't bounce back, so it's now trying to correct for the movement.

So...Green means Heading Hold mode...I have Green...and I can see that my 450 is indeed in HH mode. Awesome!

I appreciate the help, Kev!
 
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