Just getting started

[under2oz]

Hi hows everyone? I got a couple of questions for everyone, I'm new to micro flying, I've been getting the mag micro flight for sometime now. I need to know if I should buy a rec and servos or rffs and actuators? Some of the stuff I've read the servos are compareable in weight to actuators. Can someone give me some advice? Also I don't know what servos are compatable to what reciever and what actuators are compatable to a reciever. I've read so many articals I don't know. I would like to build a couple of airplanes over the winter months and stay somewhere in the 1 to 2 oz. Any info would be great. Thanks

[Mike Taylor]

The RFFS and JMP (actuator version) RXs use actuators. The RFFS was the first of the 'plug-n-play' systems, works very well, but it is rather wide band which means you may get intereference if there are several other systems transmitting while you are airborn. Bothe the RFFS and both versions of the JMP have a built-in ESC, a further weight and outlay advantage.

The JMP receivers are newer, are narrow band and have good signal rejection from other TXs. If you get the actuator version that has plugs already added for plug-n-play, it weighs more than the RFFS.

Actuators are good for model up to 1 1/2 ounces, but best suited for lighter planes. When you get over an ounce, the actuators you need are the BSD 'Standard' actuators. They weigh 2.2 grams each. For model below that, the 'mini' actuators (same as those from DWE) are about 1.1 grams each will work. If you want to have ailerons the 'standard' actuators are needed.

Over an ounce and a half, you are into the servo size of planes. The Falcon servos weigh less than the larger actuators at 1.7 grams each. These servos work with the JMP (servo version), the Cirrus Micro Joule (you need to swap a couple of leads on the plugs - not a biggee), and some other light weight RXs. These are great little servos, but are a little harder to mount than some, and they run $60 a pop. The JMP and Falcon servos make a great light weight system that can fit in the Micro-Mite 7" WS plane, so they are not limited to larger models.

The Cirrus MJ system is all complete in one package for about $120 (on sale) or $150 full price. It is the cheapest all up system, but it weighs the most at 9.7 grams. An advantage of this system is that you can get the flight pack with either a 1-cell or a 2-cell ESC that is rated at 5 amps. This will fly a pretty larger model. The servos are easy to mount and only 1/4" x 1/4" x 1". Hobby people sells this set up, and their warranty and returns policy is the best there is. I have several of these and like them very much. I tend to put these into higher performance models with 2-cells and and geared N-20 motors.

Another RX I have used is the Gasparin 'Penta' 5-channel radio. It is narrow band, very light weight, has good range, but the servos and power leads need to be soldered to the PCB. It is very small and light, but also requires an external ESC.

There are some other options like the new Falcon 'brick' with integrated RX and 2 servos for about US$134. I believe it requires an external ESC. I expect to have one of these in the near future to test out, and I cannot yet comment on its performance in the air. The front end seems very similar to the JMP and Penta designs, so it should provide similar good performance in crowded conditions. With only one board to mount, it should be the easiest to install in a model.

This field is only a couple of years old and the gear is developing fairly rapidly, serves many different needs, and rather subjective with everyone having their own opinions of what is best.

IMHO, if you can afford the expense and can live with 3 channels, I would recommend the JMP and Falcon servos. There are additional boards that you can add to the JMP to add an additional channel, and run on 2 cell instead of 1-cell. For most indoor flying the stock set-up is fine. This isn't the cheapest way to get airborn, but it does provide very good, solid performance and good 'bang for the buck' It is also pretty easy to set up and maintain, and Bob Selman (the U.S. distributor) provides good advise and timely service.

If you fly mostly alone or with just a few friends and want very light weight systems for smaller planes, the RFFS and light actuators are a good choice. If you decide to go with actuators, I prefer the 'remote' mounted ones for several reasons - primarily due the fact that they are more protected than the surface mounts and also because they make it easier to balance a model.

I hopes this helps some...

[under2oz]

Mike thanks for the info. The falcon brick is that new? Sounds like my very first rc equipment I had in the early 70's.

I plan on flying some very light planes (15-28 grams) so I guess that will be with actuators, I've read that setting them up is kind of hard.

Anything else I guess I'll use the falcon servos and jmp rx. Most of the airplanes I have found would not be over 2 oz. I'm kinda fond of the P51 and maybe an F86 (found plans for a very small one that can be converted).

Guess I'll have to make a new Christmas list for the wife along with the web addresses to get everything.

Thanks again Mike enjoyed your responce.
David

[Mike Taylor]

David,

Heres a couple of shots of actuator installations. The first one is a ;surface mounted' actuator. The magnets are mounted to the movable surface. This one was an aileron experiment, but the mounting method is the same for rudder or elevator. The instructions said to use copper or brass wire, but I found, after repeated 'attachments' to rulers, knife blades, nail heads of the work bench, etc., that each of these events required re-shaping the soft wire. Now I use steel guitar string; it springs back into shape much easier. The gold spot in front of the coil is a small rare earth magnet to provide magnetic centering and control dampening.

http://forums.radiocontrolzone.com/attachment.php?attachmentid=31767&stc=1

Here is a shot of a 'remote' actuator set-up. The front actuator is rotated 90* from the rear one. This allows the magnets to attract each other and provides centering force. This smoothes out the control inputs and keeps the surfaces from flapping or fluttering. Since the magnetic flux from the coils is also at 90*, one coil doesn't affect the other control.