aldrhan

I just got myself a Great Planes Patty Wagstaff 1/4 Extra 300S. I'm having trouble deciding what kind of radio installation I should go for though. So much advice is available from so many different sources. First off: How powerful servos do I want? I want absolute peace of mind that they will do the job, and even perhaps be possible to use in a 1/3 plane sometime in the future. The manual says minimum 60 oz-in of torque from all servos. And there's two of them on every control surface. I have a Futaba R319 DPS Reciever and Futaba 9C TX so I want Futaba servos to eliminate the risk of some sort of computer-programming-related incompability. I also would prefer them to be standard sized.

Secondly: Do I want 4,6 volt or 6 volt batteries? Someone said that if I buy too powerful servos, they might drain so much power the RX will lose signal in a 4,6 volt radio setup. And if I go with 6v, do I need to get a regulator? That just feels like one extra thing that can fail in the air.

So to sum up, an all-round futaba servo suggestion with plenty of torque would be greatly appreciated and some input on the power sources. I'm going with a glow engine if that helps so I don't need an extra battery for gas ignition.

Rcpilot

My Feedback: (78)

If your planning to get a 33% plane in the future, then buying servos that are too big for the GP Patty Wagstaff is a good idea. Lots of guys do that. It natural to move up into bigger planes in this hobby, especially when your flying Scale Aerobatic planes.

You want to use Futaba servos. Nothing wrong with that. You already stated that you want absolute peace of mind. your not looking for a servo failure. Thats also a very smart attitude to have. It's going to cost you a little bit of money for nice servos that will transition into a 33% plane later, but it's money well spent. The difference between a cheap servo and a nice servo is really noticable when flying. Not to mention that peace of mind.

Take a look at these:


Coreless servo. They will put out almost 100oz of torque at 6V. This is overkill on the Patty, but a nice servo for the future. $50 is a good price too.
http://www2.towerhobbies.com/cgi-bin...?&I=LXH299&P=0

This is a little cheaper. Standard motor, instead of coreless. But, metal gears. Probably not as precise as a coreless motor, but Futaba makes good stuff, so it will definetly work on the Patty, but I don't know about a 33% plane. It's got 124oz of torque at 6V
http://www2.towerhobbies.com/cgi-bin...?&I=LXDWF8&P=0

Batteries:
Depends on the servos. Some of the Futaba servos claim to draw excessivly high amperage. They recomend NiCd or LiPo batteries to ensure that you get plenty of amps to these servos. I think that may be outdated information. Metal Hydride (MH) batteries are available today that have very low internal resistance and are capable of delivering all the amps you need for high torque servos.

6V batteries will provide about 20% more torque than a 4.8V battery. They also allow the servos to draw more current, so they will drain down faster, but thats not really a big deal. You just buy a little bit bigger battery. MH batteries don't weigh 1/2 as much as a niCD, so buying a little bigger 6V MH battery isn't going to kill you or make the plane fly terrible. Lets face it, a few ounces isn't going to ruin the way the plane flies. If it does--then the plane was too heavy to begin with.

You DO NOT need a regulator for a 6V battery pack. UNLESS you buy some of those Futaba servos that are only rated for 4.8V. Don't buy a regulator for a 6V battery system. You are right when you pointed out that it's just another failure point.

In my opinion--LiPo batteries aren't necessary in the GP Patty. They aren't NECESSARY at all. Not in ANY plane. It's just a matter of preference that different guys have. MH batteries have come a long way. You can buy MH battery packs that have cells inside that were originally designed to electric cars. They are high output, high discharge, high amperage batteries and they will work fine in just about every airplane. They will put out 15amps or even 20amps continuously. If thats not enough for your model airplane--then you need to just go get a pilots license and fly the real thing. 20 amps will feed 3 amps CONTINUOUSLY to 6 or 7 really kick-butt high torque digital servos. I dare you to try and fly an airplane and load all 7 servos at 3 amps continuously untill you run the battery down.

I'd go to NO BS batteries at www.hangtimes.com or go to www.radicalrc.com and buy a 6V MH battery. Mah rating should be 1600--1800 MINIMUM. I'd probably buy something like a 2300mah or 2700mah battery for the GP Patty Wagstaff. That should give you plenty of power to fly 4 or 5 times without worrying about it.

You'll want different batteries--or maybe dual batteries when you move up to the 33% plane--so don't worry about that right now. Just get a good solid battery for the GP Patty and fly it. Don't go cheap on your battery. You can land an airplane when the engine quits. You can land an airplane if you loose a servo. You can land an airplane if you loose a control surface. I've seen guys land airplanes with huge holes in the wings. You CANNOT land an airplane without a BATTERY.

Switches:
A battery is only as good as the switch. Get a good switch for your battery. Cermark makes heavy duty switches. Hobbico makes heavy duty switches--I've been using them for years without any failures. I replace them every season though. $20 for a switch and $40 for a battery is darn cheap insurance for your $1700 plane. But, thats just my opinion. I don't know anyone else that does it.

Use heavy duty servo leads too. Hobbico makes 20ga leads for a good price.

Think heavy duty on everything. Don't buy cheap servos. Don't buy cheap extensions or switches. Get a solid MH battery. Don't make it too complicated. Regualtors are not necessary with a 6V battery system.

Good luck.