a610412

Ok, here we go on all the Pro's and Con's to a Duct Fan Tail for a micro Heli.

All the obvious reasons I had to install a Duct Fan Tail on my Blade CP where:

1. I can land on grass without the tail beeing stoped by grass.
2. You would think with this kind of setup the tail would be more powerful and more efficient.
3. It looks very unique.
4. You would think it's alot more sturdy and can take a beating.

Now the Con's as well as the facts

1. Believe it or not, a Duct Fan Tail weighs much more then you think. I had to shorten my boom 3.5 inches in order for a 1500mah 3 cell Lipo to be balanced. I altered my Canopy by cutting out the bottom part for the battery to be moved as forward as possible. Also, I moved my 4-1 forward half an inch for this to actually be balanced. My other Lipo 3 cell 700mah was way too light for this set-up and therefore I couldn't use it.
2. I used a 40H duct fan that is designed for up to 12V. It has six fans on it. You would think it's powerful, but it's really not enough. It's fine for slow flight, but would never be able to keep up with acrobatics. Also, it is not as efficient or as responsive as a Direct Tail or a Geared tail blade. It really does suck your battery dry because most of the time you're at full throttle!
3. I bought the carbon frame for it to hold the duct fan into place. I didn't have to drill anything. I've been flying heli's for 6 months and can say that I'm not a beginner and know how to land a heli. After tuning and recalibrating everything for the duct fan tail, I took it up for a spin. I was only able to fly for about 5 minutes with flat bottoms as I noticed the battery can't feed enough power into the duct fan for it to perform normal flight. So I decided to set it down. Just from setting it down on the ground, one of my six blades in the rear broke off, caused everything in the rear to be unbalanced and ripped the entire motor apart. I haven't had to replace my blades for three months. Now they're trashed.
4. Flying idle-up and duct fan is very difficult, the gyro is not able to produce the right inputs and lags quit a bit even at max sensitivity. Therefore alot of manual input for rudder is needed. most often your always putting in right rudder.
5. Since the heli weighs alot more, your going to have to add considerably more power for hover. My flight time on my 3 cell 1500 mah lipo with flat bottoms went from 17-20 minutes all the way down to 5 minutes. That's a major decrease.


Conclusion:
I'd advice not to install a duct fan tail on a light weight heli.

credence

My Feedback: (2)

Shortening your tail boom will affect the motors power to counter main blade torque. While I don't have any experience with ducted fans, I do know that shortening the tail boom probably won't help matters and make tail control worse. I understand you had to balance the heli, but it doesn't seem like an ideal solution to me. A new landing gear system or something that allows you to mount the battery at the front of the helicopter would've been better.

Also, it's well known that ducted fans aren't very efficent compared to a full prop setup, so i've never really understood the facination with using them other than for scale looks .

a610412

My main purpose of using a duct fan tail was to be able to land on grass and not have my tail stop moving. That caused so many of my crashes durring the summer.

Gorgok

Easier solution would have been to make a heli pad... Like a piece of plywood or something (or cardboard if it doesn't get blown away.

=D

credence

My Feedback: (2)

Yep, that's pretty much it. I fly off of and land on a piece of plywood I had laying around. Worked great.