Originally Posted by Snowbird One

....It's interesting to note that the recommended MC35s aren't anywhere near as good as any we are discussing here!

By the way, the www.servodatabase.com website is such a useful reference (as someone stated many hundreds of pages ago!). You can make your own comparison chart with just a click or two

+1

I've got 74 flights and use hs 81mg's everywhere. I believe they are really hs 82mgs as the specs are identical. No issues whatsoever. They are fast, and the flight surfaces are as tight as they were on maiden. I got 131 mph on one slight wind aided pass, not bad for stock. Totally happy with this jet. Stephan

I have several Habu's and have worried over my servo selection until now. I run a mix of servos in my Habu's from Hitec HS 82mg, HS 85mg, Ino Lab digitals and now HS 5085mg.

I was worried about having the right servos or at least a good enough servo to stay out of trouble. I think we can get away with anything from Hitec 81 to Savox servos and be just fine. I did a little research of the recommended servos and what I was running;

V Torque V Torque
Jr. 368 4.8v 53 oz
Jr MC 35 4.8v 30 oz 6v 35oz
HS 81 4.8v 36.1 6v 41
HS 82mg 4.8 38.9 6v 47
HS 85 4.8 41.66 6v 48.6

These servos are all very close in size, torque and weight. Well actually the Hitec servos are a little stronger than the Jr MC 35....well maybe more than a little.

After this little research project I feel just fine flying Hitec servos in all of my Habu's. As far as the rudder servo, flutter could be an issue but what about the elevator and ailerons? I'm not sure what the thinking is with a digital, higher torque servo on the rudder. In one I'm running a HS 85mg on the rudder and the other one I'm using a HS 82mg. I do knife edge and point rolls....so far everything is good with no slop.

I will never argue about the quality of JR servos, as good as it gets as far as I'm concerned, I own a ton of them, just no small ones. I also think Hitec is a pretty good servos as well and I'm not afraid to use them.

From www.servodatabase.com

Originally Posted by Snowbird One

From www.servodatabase.com

Got me, that was easier than looking them all up

I did not know you could compare them.

Good work!

Originally Posted by Snowbird One

I'm sorry, maybe I mis-worded it. I meant to say why use a SECOND BEC. You already have the one on the ESC, why get a second one, and cut one of the wires. Wouldn't a voltage regulator do the same thing? I really don't get it what does the SECOND BEC do that the voltage regulator wouldn't. And, yes, like I say, I'll get an A123 for redundancy, but I am just so curious about it.

I do not agree with the statement that a servo does not add to or prevent flutter. Sloppiness in any part of the linkage system CAN lead to flutter. A servo that has teeth that are not meshing nicely will certainly introduce 'slop' -no matter how little it may be; likewise, also will a shaft not firmly seated in a bushing or bearing. This CAN allow the control surface to begin to oscillate. Hit the right frequency, and you will experience flutter.

So by the predominant choice of the 85MG people are saying that it's better to have the heavier, slower 85MG because it has the ball bearing?? With so little understanding of how the ball bearing is an advantage I don't understand why they're choosing that over the 82MG. Not quite sure I understand the 'robust' statement, either. Robust because the shaft is supported by a ball bearing?

It's interesting to note that the recommended MC35s aren't anywhere near as good as any we are discussing here!

By the way, the www.servodatabase.com website is such a useful reference (as someone stated many hundreds of pages ago!). You can make your own comparison chart with just a click or two!


85HB? Is that another one? I couldn't find it in the servodatabase.com website.

Sorry i couldn't be more helpfull. By robust i just meant "bigger, stronger, more powerful, etc." Now that you mention it I guess an old worn out sloppy servo with bad bearings could allow a surface to flutter. My bad on the "HB" designation for the 85's. The non MG version of the servo has nylon gears, not Karbonite, which Hitec calls "HB". Hitec doesn't use any designation for nylon.

Ok, I have a question about balancing...

How is it that you're able to balance to within a mm? A lot of you are reporting that you've balanced it at, for example, 117mm. That's a pretty tight tolerance!

If you're balancing as per the manual, you can't even see the lines you've marked (though I did just come up with an idea to use a mirror on the table underneath the wing!), and the tips on your balancing device must surely be larger than a millimeter?

Also, even if you have such an fine tip on the type of balance illustrated, ANY amount out of level means you're not truly at that balance point. This leads to the question: what is your reference line, and how do you go about ensuring that reference line is level? (I don't mean adding weight to the nose or tail, I mean, how do you actually get a measurement from that reference line? For example, if they had a nice flat surface sanded into the fuselage, you could put a bubble level there; but I highly doubt it offers such a luxury.)

So...how do you guys do it?

How difficult is it to switch from the stock landing gear to retractable landing gear (not necessarily E-Flite's) later?

The E-flight gear is a drop in fit and works well. For any other retractable gear you will be on your own (unless someone else has done it). I honestly don't see where you could put a retract servo in the fuselage for a servo actuated retract, you might be able to get an air cylinder under the battery tray, I don't know.
The good news about balancing is the Habu is very forgiving, it has a wide acceptable CG range. I agree that measuring it within a mm would take a pretty sophisticated instrument. I like to put a strip of thick tape like electrical or masking tape the width of the CG range under my wings near the fuselage. So I can quickly put my fingers under the jet at the field and feel for the tapes. i just balance it on my fingertips, I like to fly it at the aft CG point specified in the manual so I just put my fingertips on the aft edge of the tape and move whatever battery is in there until I'm happy. I do this on all my planes even for instance if I am flying a foamy or slope glider in high winds I can quickly find a more forward CG when I install the battery at the field.

Snowbird, thanks for the servo site. That is a great way to compare servos.

I balanced my Habu in the middle of the range using a piece of Tamiya tape on the top of the wing to mark the location. Then I use a balancing machine with the Habu inverted. I remove my tape when I have installed everything. Like Husafreak says, the CG is somewhat forgiving, so shoot for the middle, and close is good enough.

Ok, so when someone says they're balancing it at xxx millimeters, basically they're full of it?? (j/k) But basically you're saying no one really has any idea within even several mm what their balance point is.

As for the gear I was actually more asking about if I STARTED with fixed gear, and then later changed over to retracts (to save on the initial cost) would that be detrimental in some way? Ie. would I being tearing out something that's been glued, leaving a mess?

You're welcome for the link, but I am really just reiterating what someone had posted several hundred pages ago! (This thread really is too long!) I haven't checked to verify the data in there with any of the official specs, but in this case ignorance is bliss. Just use at your own risk, I guess!

Snowbird,

Drop in fit is the answer to your gear question. If you start with the standard gear and decide to switch to the eflite electrics later, they will drop right in. You do need to make some provision for getting the servo leads to the etracts later on. As stated above, any other retract option is likely to result in some cutting and fitting.

You can get the CG on the number using a CG mach.

Tony

Tony:
You can get the CG on the number using a CG mach.

True....or use use a pair of calipers...no big deal on finding the CG......or once you mark the CG on the wing use your fingers to find the balance point. On most planes the recommended Cg is a starting point and the HAbu is no different....and in fact is very forgiving as to the CG setup.

Remember to balance it upside down if using the finger method or a balancer!