dfalcon

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Finally ordered a brushless motor and esc today for my axe. I found a Himax 2025-4200 over at rcgroups for a fairly low price, and I ordered a Heli-max 25A esc and a 9T pinion from tower. Can't wait!!

MsDarla

Awesome
The helicopter reminds me of the Falcon 3D.
http://www.hobby-lobby.com/falcon.htm

dfalcon

My Feedback: (76)

Actually, the Falcon3D with it's driven, gyro/servo-operated tail is more along the lines of a shogun/zoom/mx400. I had a Shogun V1 about 6 months ago (shaft driven tail version, not belt driven tail), and it was a maintenance nightmare. I didn't even have to crash that thing and something would break. That happened about 4 times, and I got tired of it and sold it.
But back to your point, yeah, the Axe with it's full-body frame (the first thing I noticed and fell in love with) does look more like the Falcon although it functions more like a Blade.

DscottM83

for 100 more the falcon looks like a steal, wish i would of knew about it earlier [&o]

PilotLight

My Feedback: (1)

You could always sell on classifieds or ebay and re-up. With Tower's supply backup, I bet it will sell pretty quick.

I'm keeping mine.

DscottM83

Its on ebay now, thanks

Heliko

The Falcon looks like a great little bird. It's very smooth in the vid. It looks a bit more intricate then the AXE which may mean more damage in a crash, but my only real concern would be parts availability as it seems that many parts aren't available till next month. Also Hobby Lobby seems like the only place you can get it or the parts. I guess I've heard the all your eggs in one basket saying too many times.

Either way good luck with it.

Getting back on track though, don't forget to post when you get the brushless set-up working Mr. thefalcon. I was thinking of brushless conversion too.

dfalcon

My Feedback: (76)

You could most likely use shogun, zoom, or mx400 parts on it [Falcon]. They're all pretty similar.

DscottM83

Thanks, the AXE sold very quickly on ebay with a BIN, ill report back with how this bird compares with the AXE. Falcon is on order now.

outtamyway

Wow, look at this price... [link=http://cgi.ebay.com/Falcon-3D-6-Channel-Aerobatic-R-C-Helicopter-NEW_W0QQitemZ230076834534QQihZ013QQcategoryZ2563QQ ssPageNameZWDVWQQrdZ1QQcmdZViewItem?hash=item23007 6834534]Falcon 3d[/link]

That is with 2 sets of Carbon Fiber Rotor Blades, LiPoly, HH Gyro, Brushless, Heat Sinks, Training Wheels etc.

dfalcon

My Feedback: (76)

Wow! Maybe I'll sell the brushless Axe (as soon as it's put together) and buy that!

outtamyway

I thought you already owned a Falcon?

dfalcon

My Feedback: (76)

nope.

PilotLight

My Feedback: (1)

Mr. thefalcon,

Not sure how you determined the proper Kv motor size and pinion size, but here is a calculator from another Heli enthusiast. Not sure of the accuracy, but who knows, maybe its been tested.

Looking forward to hearing of your successes and recommendations.

http://dhrc.rchomepage.com/calcAdvanced.htm

dfalcon

My Feedback: (76)

Thanks, that's pretty handy and worth bookmarking. I've already begun to think that I might need a larger pinion at some point in time, when I'm comfortable with inverted hovering enough to try some more intensive 3D stuff.

Just by making sense of things on my own, I initially used (motor kV) * (approx. loaded battery voltage) * (pinion teeth) / (spur teeth) = rpm. Using this with 10.5V (I don't expect the motor to be working too hard and drawing the voltage down too much), 9T pinion, 4200kV Himax 2025, and 180T spur, I got 2205 rpm's. I trusted myself and ordered the components based on this information.

Then I found an equation [link=http://www.helihobby.com/html/going_brushless.html]here[/link] at helihobby, and thought 'Uh, oh!' when I first saw it. But it still gave me the same result:

(Target Head Speed x Main Gear Teeth) / (Motor Kv x Voltage x Percent Motor Efficiency) = Pinion Gear Teeth
(2000rpm * 180T) / (4200kV * 11.1V * 85% efficeincy) = 9.08-tooth pinion

When I've finally advanced beyond the basics, I'll probably go with an 10T or 11T pinion to get somewhere around 2400 to 2600 rpm's. But 9T will be a good starting point for the motor I've got.

PilotLight

My Feedback: (1)

I think there is something missing in this computation. If the motor stays the same speed, yes you will see a faster head speed with a larger pinion. However, what actually happens is the larger pinion causes the motor to turn a little slower at the same head speed as before and this causes more amps to be drawn through the motor.

Its like putting a bigger prop on the same small motor. If you go from a 6x4 prop to a 10x4 prop, you will not get more thrust. The motor just slows and bogs down and pulls more amps. The slower an electric motor is "forced" to turn, the more amps it will pull. You are looking for a balance.

Where did you get 2000 RPM for head speed?

MsDarla

Waiting to see one.
Especially a video of it flying.

dfalcon

My Feedback: (76)

I don't think that will will be the case in my setup, because the motor is a little oversized for the helicopter. Imagine you had the himax 2025 in the himax gearbox. Starting with 6.6:1 gearing and 3 cells with a small prop, like an 8x3.8. The motor would barely be loaded at full throttle, drawing 2.8 amps with a prop rpm of 6806. Now check the same motor/prop, but this time with a 4.43:1 gear ratio. The motor would now draw 6.8 amps at WOT with a prop rpm of 9589.

I'm not going to be pushing the Himax 2025 to it's limits like a Shogun or MX400 could with their larger rotors. So I believe the gearbox analogy above would hold true for the axe when going from 9T to 10T pinions (20:1 down to 18:1 gear ratio) and even up to an 11T pinion (16.36:1).

The relationship between gear ratios and head speed will not be linear, as the motor bogs down as you mentioned. But there will be an increase in headspeed nonetheless. <<<EDIT: from gearbox example above: gear ratios 6.6/4.43 = 1.49, rpm 9589/6806 = 1.41>>>

If I were going to use my smaller Himax 2015, I would be looking for the balance you mentioned. But I've got power to spare and room to play with the larger motor.

I googled. 2000 seemed to be the consensus among many sites as the upper end for hovering and sport flying a heli of this size. 2200 to 2600 is what I found was recommended in many places for 3D flying.

dfalcon

My Feedback: (76)

Had a setback today on my timeline (expected to go brushless tomorrow). Like money burning a hole in one's wallet, I couldn't just let the new motor sit there like that. I put a 4.7x4.2 APC E prop on it, and was going to power it with a 2s 2,080mAh battery. I noticed that the prop wasn't tracking properly so I assumed the shaft was bent. While trying to 'gently' straighten it bit by bit, I snapped the protruding part of the shaft off. Anyone know how to remove the end caps on the Himax inrunners? Are they pressed, glued, or threaded?
The rotor/shaft assembly is $15, but not knowing how to remove the broken one, I think I'm better off buying a new one.

no hesitation

Enough with all this "Falcon 3d" stuff. I wanna hear about Mr. Falcon going brushless with the high potential of the Axe cp!!!!!!!

PilotLight

My Feedback: (1)

Me too!! How's it coming Mr. Falcon?

Gamemaker

looking at the numbers using a Himax 2025-5300 would be better that is with 180T on main wheel i didn't count the teath yet LOL

from the looks of the markings on the motor

(Motor Kv x Voltage x Percent Motor Efficiency x Pinion Gear Teeth) / Main Gear Teeth = Target Head Speed
(4530 x 7.9 x .85 x 14) / 180 = 2365.9183333333333333333333333333
now the 180 main gear is est i didn't count the teeth yet
the 7.9v is from a multimeater on the power connection to the main motor with the idle up switch off
the 4530kv is from markings on motor
first line looks to be a series number
second line is model number ie 380 motor with 4530kv
and last is manufactuer date 07/29/06
sestcl
srs-380sh-4530
072906

bryon261

i see now and again comments about the falcon 3d, is it as good as it looks? i have a purple axe cp with servo and soon to be gyro upgrade , once it gets here. was thinking of getting the falcon for my second copter ,once i become a better pilot.it sure looks good and it comes with lipo batteries. i still have to upgrade to lipos. once the new gyro is installed i'll have too, since the current draw will increase.with nimh batt.'s i'm getting about 4 minutes.

Rotor13B

I bought a lipo battery, charger combo with 120ac wall wart and dc alligator clips off of ebay for 42 bucks shipped. It's only 1000mah but it is a huge increase of run time from the stock nimh. I'm tempted to buy another battery also cuz there selling them for 16 bucks.

dfalcon

My Feedback: (76)

Well boys, I'm out of the axe game. I listed the Axe for sale and ended up trading it with all the brushless stuff I bought for it for a Raptor 30 V2 with motor and all digital servos. It should be here Monday... I've got the Tx and Rx, just need to pick up a gyro. Good luck and happy flying to everyone.