Hey everyone,

I decided that my question was probably too simple for the servo forum, so I came to you guys!

Right now I am just about to finish my trainer, the Sig Kadet. Everything is going great, I am planning on buying a Futaba or JR radio with the servos included. I understand this much. I am also about to start working on my new project, its called the Bushwacker. I don't really understand this part: Will the servos in the Kadet be ill the servos be too big for the Bushwacker? We are going from a .40 sized engine to .15! Am I just doubting the power of the servos? There has to be some piece of info that I'm missing.

Thanks in advance!

Medic

What size servos does the smaller plane call for? If it calls for standard size servos, like your Kadet does) and you verify that there is room, you can probbaly use them. If not, you may want to look at smaller servos. The only other consideration is weight. Maybe someone else here has built a few .15 size models and can give you a better answer, all of mine have been either .40 and larger or 1/2A.

Doesn't the new aircraft specs spell out what servo's you should use? Well, not specifically what servos, but what type of servo to use.

I will repeat what I wrote in another forum. Consider the Spektrum DX7 radio system. It uses the JR 821 digital servo and is expandable to include other aircraft. Other servo's will work with the RX. The main point with this radio is that it is completely free of inteference issues and can be operated no matter what other radio systems are being used at you field. And, it comes with four of the JR 821 servo's. (labled Spektrum, but they are the JR digitals.)

DS.

My planes that are that small get micro-servos for both weight and space reasons. The first time I built a .60 size plane, it was totally incredible to have so much room in the fusilage for servos and radio gear.

Is the Bushwacker an old kit? I remember that kit back in the 80's and we used (then) standard servos (~50 oz. torque) and didn't have any problems.....

Bushwacker
http://www.modelaircraft.org/plansall/b-plans.pdf
pg 62
An old Marks Models plane.

I have actually ordered the plans, and they should come soon. I cannot wait until I can build it!

I was just wondering if the smaller servos had less strength or power as the big ones. I do understand that bigger servos will always have more power, but I was wondering if the micro servos would be too weak.

So the micro servos that come with the Futaba 6EXS will be fine?

medic

Get yourself a radio with good standard servos. I would recommend a JR.

For the bushwacker, I would HIGHLY recommend getting some micro servos. But there are some problems associated with this. While I have seen kits in the .15 size range that had standard size servo's in the plan, most poeple put micros in.

The HS-81 is a good all around small servo. There is a metal gear version which is good when you are goign to belly land or worry about stripping gears. The HS-55 is even smaller and is nice, but the gears can strip relatively easy.

The HS-55 can be gotten for $10-13, then HS-81 for $15-17 (metal gear version for about $23-25 i think).

There is another option, the hs-56. It is the same size as the HS-55, but it has a karbonite gear and has a bit more power to it.

As you can see, these servos aren't that expensive. Your better off gettign your radio with some nice servo's and then buying micro's specific to your application as needed.

Whatever you use, i would suggest using an hs-55 for your throttle, maybe even a smaller (ie,3.6-5gram servo that can be gotten after a little careful shopping. hobby-lobby has them) servo to help keep weight down. Also, the front of these small planes can get pretty tight.

I also recommend trying to lighten the plane as much as possible. Even small weight savings make a difference here.

Good luck. If you need more help, visit the 1/2a forums.

There are 2 6EXS systems offered by Tower. If you get this one
http://www2.towerhobbies.com/cgi-bin...&I=LXKAJ1**&P=
you get a mini RX and micro servos. The servos would probably be marginally OK but the RX in this package is for park flyers and is recommended for 650 ft range or less.
http://www2.towerhobbies.com/cgi-bin...?&I=LXJSP9&P=V

The other system
http://www2.towerhobbies.com/cgi-bin...&I=LXHYK7**&P=
has a standard RX and standard servos with a bit more power. If the servos in this system will fit your plane I'd go with it.

Good microservo's have a surprizing amount of power, don't skimp in this area or you'll be paying for it with a crashed plane. I bought a bunch of cheap ones early on thinking I'm getting a deal only to be paying for it in crashed planes due to malfunction, glitches, lack of response and torque. If you are shopping for the radio, look at the radio's attributes alone, the rx and servo's normally given with them as a package are not necessarily always top of the line and you'll likely have several sets of them through the years while keeping the same radio.

As I stated above, be sure you get the correct RX for your application as well.