Mini Heli Blog

Axe CPv3 Using a Blade CP Rear Tail Rotor

The new Axe CPv3 has a direct-drive tail rotor that replaced it’s earlier version which was setup with a larger rotor that was gear driven in the CP. While this change definitely looks cooler and more scale, the direct drive rotor seems to break if you just look at it wrong. I’ve had it break in the air for no apparent reason resulting in a crash, I’ve had it just come off all-together on a hard landing (that didn’t hit the rotor), and if you do scrape it or touch it while it’s moving at all it’s a goner for sure. The other problem with this setup is that the non-geared motor gets really hot and I’ve already burned one out. These motors are $27.99 at my local hobby shop, more than the main motor!

So I decided to switch to the tail setup on the original Axe CP (which is the same as the Blade CP, Hummingbird FP, Sabre FP and most other micro helis) and so far it’s been great. I bought the CF boom for the Axe CP which came with most of the hardware for the conversion, and I used the gear, tail motor and bearings from an old Sabre FP I had laying around. Finally for strength, I bought the CF rotor for the Blade CP. Tail authority is just as strong if not stronger, piros seem faster and the few times that i’ve scraped the tail on the ground, it’s only knicked the CF tail, or brought it out of the gear, instead of snapping at the same point like all of the other CPv3 tails I went through. I’m also using the motor out of the Sabre, which is a $7 replacement part opposed to the near $30 Axe motor.

I also keep hearing that Helimax is coming out with a torque tube gear driven tail conversion for Axe CP, which I would definitely be interested in. It’s been on Tower Hobbies website for a while but each month the expected arrival date gets pushed back to the following month, so who knows if it will ever show up.

Picked up a Spektrum Dx6i for my Axe CP and T-Rex 450

I finally finished my T-Rex 450 SA yesterday when I picked up a Spektrum Dx6i w/ AR6200 receiver from my local hobbyshop.

I had never programmed a computer radio, let alone the settings for a helicopter, but I found all of it to be very intuitive and straight forward. The internet is also filled with different people’s settings, so it was easy to setup for both my Axe CPv3 and the T-Rex 450. I’ve only flown the T-Rex once now, just a simple tail-in hover to get everything balanced properly. It’s amazing how much better that hovers than my CP though. I can take my hands off the sticks for more than a few seconds before it starts to drift one way or the other. The CPv3 flys much better with the Spektrum than it did the stock radio. The subtrim allows me to get the swashplate balanced very well, and the swashplate mix and the expo allows me to get the right sensitivity.

I’m still trying to figure out the perfect pitch and throttle settings for the Axe and will work on the T-Rex once I get a bit more comfortable with it. But yeh, so far I’m very happy with the Spektrum Dx6i. The radio and receiver was $199 at Pacific Coast Hobbies in Lomita, CA, and I’ve seen it for a few bucks less online. The second digital receiver that I bought for my Axe was $49.

Differences Between Axe CP and CPv3 Tail Motor

The tail motor in the Axe CPv3 is ungeared and runs at a very high RPM, because of this, I’ve already burned out two motors at a very pricey $24.99 a piece. I’m sure these cost Helimax $2 each, but they overcharge for all of their replacement parts. They hook you in with an affordable helicopter and then get you when you need to replace parts. This is one reason why I’m looking forward to moving up to the T-Rex 450, because replacement parts cost about half as much.

Anyway, the last time I burned out a CPv3 motor in my Axe, my local hobby shop didn’t have the replacement motor for the CPv3, but did have the CP version with a brass gear on the end. They assured me it was the same motor, but when I got home, popped off the gear and put on the prop, I realized the shaft was much shorter than the original motor. The prop still fit on, but I’ve lost two props now, on a hard landing where the prop pops off and slams into the ground, breaking. I don’t think there’s any way i could further secure the prop, so it looks like I’m just going to have to replace the motor again when I get around to it. Anyway, Make sure if you replace the tail motor to wait for the correct one.

Welcome to the Mini Heli Blog

This blog will feature my experiences building, flying and crashing r/c helicopters. My first helicopter was a Century Hummingbird FP, which I couldn’t hover to save my life. A couple of years later, I picked up a Helimax Axe CPv3 and learned to hover it quite well. After learning basic tail-in hovering on the Axe, I could then hover the less stable Hummingbird with ease. At this point, I can hover tail/side/nose in and fly simple circuits and forward flight. I’m also building an Align T-Rex 450 which I hope to have ready in a couple of weeks. Stay tuned!