Gohbee
Senior Heliman
Location: SC
| Ok....let me try to break it down as I see it. ....and let me emphasize "as I see it".
Torque:
A minumum torque is the issue when trying to size a servo to a particular size helicopter. The bigger and heavier the heli is, it stands to reason that a servo capable of more torque is required. My recommendation is to stick with servos greater than 80oz-in of torque on a 90 size machine. Preferably find a servo that is greater than 100 oz-in of torque for 3D. (Again my opinion) On the flip side a servo with an extraordinary amount of torque (ex. 330oz-in) will likely yield little performance increase over a servo with plenty of torque (ex. 150oz-in). Law of diminishing return. ...on the other hand...
Speed:
IMHO, speed is always good no matter the size of the heli. The faster the servo the crisper or "more real time" the response. This will aid your flying no matter your skill level. The slowest servo I would consider at this time would be around .19sec/60deg. Anything faster is going to help your flying.
Now. Your question was...what's the "best" servo for a 90 size heli. I assume when you say "best" you are refering to performance. First, I would only consider digital servos in this day and age. Inexpensive digitals are now available, so I think there's no reason to purchase analog servos. (again my opinion) With this in mind, purchase the fastest servo you can afford that meets the minimum amount of torque that your helicopter requires.
Here are some suggestions:
Bluebird 821's => 82oz-in, .11sec/60deg
Bluebird 820's => 130oz-in, .11sec/60deg
Hitec 6965's => 91oz-in, .10sec/60deg
JR 8717's => 160oz-in, .09sec/60deg
Futaba 9452's => 127oz-in. .11sec/60deg
Some of these we stock, some we don't. But this will give you a starting point. The main thing for most folks is to find a good performance servo that's in your budget. (Note: We are way behind in getting product up on our website. As a result we have a lot more stuff in stock than what the website shows. So if you have any questions, give me a call.)
One thing I will note. Be careful when comparing mfg's posted speed and torque numbers. I haven't looked into it, but I've heard there are differences in how some mfg's measure these values. So the numbers may not be an "apple to apple" comparison.
Also, don't forget to checkout the speed and torque at higher voltages. Some servos can handle 6V input and thus you'll get higher performance.
And last but not least. Don't forget to look at the servo's weight. Some servos have pretty impressive performance but they're really heavy compared to others. Heavy servos multiplied by 3 or 4 can add up pretty quickly if you're trying to outfit a 3D monster machine.
just my 2 cents........BTW, I don't consider myself an expert on servos....so I'm sure there are others out there who are more knowledgable and can offer better advice.
-David |
