Hi Guys. I am building my first QM40 plane and need some help with servo selection.

QM is just getting started in South Africa and I have only seen one fly. I have no feel for the servo power requirments.

I was planning to use a Futaba 9101 servo for elavator and ailerons. I have the servos from my old .60 pattern planes. They are newish and no use in a 140 size plane and was wondering if they whould be OK in a QM.

I don't mind buying new servos if the 9101 is not suitable but to find a use for "good" unused servos is always a pleasure.

My concern is the low power (+- 3 kg) and the coreless motor.

Will they be OK ?

Paul

Hi guys.

If no one knows the 9101 servo, what do you guys use and i will check it out for spec.

Thanks

Paul

Not knowing about futaba ,,, but you may want to look at them Jr 3121 or the DS3421's,,, a little pricey but worth it

http://horizon.hobbyshopnow.com/products/jr.asp



BV

For us Futaba guys racing Q40's are using the Futaba MG S3102's elev rud MG S3002's for ail S3101 for eng. shut off Here in the states

Hi Guys

Thanks for the advice guys.

I have some jr3421's in my latest quickie and they are great.

The Futaba 3102 is a little more powerful and a bit slower than the 9101 and the 3002 is about the same power and also a bit slower than the 9101. I don't have a real space problem so don't need mini servos. I think i will use my 9101's.

Thanks again.

Paul

The Q40 and Quikie 500 do not need fast servos They use the Slower mini's because they have a better response with the faster airplanes Fast servo's and Fast Airplanes are not a good combination. The other reason for the mini servo's is the weight savings the lighter the plane the faster it goes

Hi, Fast servo no good for fast plane.....this seems strange to me, but i'll have to believe you. I understand that a slower pitch and roll rate might be better in racing to avoid over controle and to keep a smooth line. But a slow servo....?????

I always find a fast, powerfull and good centering servo best in any application. Pylon / pattern / heli and even just sunday flying...

As a rule of thumb the faster the less powerfull and the reverse is also true. Untill a newer better servo comes out. but then it that range the same is true.

Thanks

Paul

Hi pwood. You have to remember most sport planes only fly at an average air speed of 80 MPH the Q40 you are getting ready will do an easy 180 mph. if it is the same competition style we fly in the states. Full control service travel in say elev is less than 1/8" up and 1/8"down. Know put in fast servo's and you are going to have one fun time trying to control that Baby. I guess you can do what you want.Have Fun!!! Here is a Pic of my practice Plane the eng I fly it with is a Nelson Q40 This Plane will do an easy 180 mph, with the futaba servo's all day long. I listed the servo# earlier

For what it's worth, I prefer to use fairly fast servos and tone down the response around neutral using exponential -- with the JR transmitter, "+12%" on aileron and "+20%" on elevator suits my style.

You can get more speed and power out of your servos by boosting the voltage from 4.8 volts to 6 volts. A 5-cell, 270mah or 300 mah pack is ideal for this. Be aware that it will take longer to fully charge unless you also upgrade your charging system. Also, the current drain will be higher so keep a voltage meter handy (the kind that puts a 200ma load on the system when measuring) and don't fly if it drops below about 5.8 volts.

That being said, I've now gone back to 4-cell packs and things are ka-nuckin' along just fine ... JR 901s or 3021s on elevator and aileron, JR 341s or Hitec 85s on rudder and shutoff.

I prefer nylon gears because they're lighter, smoother, and never get sloppy. Yes, you will wipe them out in a crash, but if you crash a Q40 you'll have a lot of other problems that are 'way more expensive than servo gears!

Good question, answer: every application has it requirements. In the case of a Q-40 vibration must be considered, so a good quality servo is a must.

As for speed my opinion says faster is better. When I first started racing just staying in the sky and not killing my competitors were high on my list. Now that I can scribe the corner pretty tight I can sense the difference in servo speed when going from one end of servo travel to the other. When I fly my old scat cat with Futaba 148 servos I learned to let off of full elevator going around turn 1 before it really did, taking in account the slower servo speed. When I bought my first "fast servos" I could sense the difference and gained confidence knowing I didn't have time my stick inputs around the the fact of waiting for the servo to catch up.

This of course is just my opinion to a very good question.

We need a world RCU pylon championship race. That would be sweet...

Hi Jerrysu31

I must seem like a real ***. Sorry, I ask for yous advice and then try shoot you down.....I do appreciate your advice. I am new to QM40 and need all the pointers I can get.

Paul