Hey Guys,
I am just about ready to buy my first 42% plane and have been out of big planes for long enough that I have no experience with the more modern options for power systems. The plane I am looking at buying is a Dietrich 42% Extra 260. It has JR 8611a's all around, 2 per aileron, 1 per elevator half (I may switch to 8711's?? Different topic), and 2 on rudder. It has 2 Li-ion rx packs running through TBM regulators set at 6.0 volts and is using JR heavy duty switches. I fly on a 2.4ghz radio now, so here is my question. The system as it stands right now has very little safety/redundancy built into it as I see it. I am paranoid about the setup on this plane as it is my first 40% er. I can buy the plane with a JR9000 receiver in it, or I can buy without. Should I get the 9000 and buy a power expander to add redundancy, or get an AR9100 that has "powersafe" features built into it? If I go with a power expander setup, what exactly should I get? Is the only real advantage to teh AR9100 reciever the pwer handling capabilites? Meaning, if I go with a power expander, is the AR9000 good enough, or is there a reason to get an AR9100 instead? Thanks for any input and let me know if you need any more info to be able to answer accurately.

Thanks,
Todd

Here's my 2 cents worth. That and a 5 dollar bill will get you a cup of coffee.

I spoke with Bob Ritchey who makes the Smart Fly products at the AMA show this past weekend. I sent him an email asking him for a clearer explanation on this subject. Here's his response.

"Hi Steve,
The actual radio circuits inside the two receivers are the same. The
AR9100 is harder to hook up
to any power system because of the way the receiver has to get
power. To hook up an AR9100
to one of our systems you have to make an adapter for the two power
leads to standard R/C
plugs. Then you plug those into two unused servo outputs. On the
leads coming from our unit
into the receiver servo ports, on the two end ones, that have power
and ground also, you have to
remove or cut the red wire so that the higher voltage on the receiver
bus does not back-voltage
the 5V regulator and burn up the ICs inside our unit. Its just a
major hassle and you have no
advantage of the AR9100 over the AR9000 as far as the performance goes.
Let me know if you have any other questions."

The benefit to using the power expander in my opinion is this. The connectors for the servos are rated at a maximum of 3 amps. When you run a matchbox or a "Y" cable you are running more than one servo per connector. It wouldn't take much to exceed the 3 amp max. With the power expander you can plug multiple servo into one channel so you are not putting more than one servo per connector. Of course there are other benefits to using the power expander, but I see that as the most important.

If you are going to use the Li-on battery packs you should get what is called a "DC up" from Fromeco to ensure that you don't have any issues with brown outs. I don't know about the TBM regulators, but I only use the ones that Fromeco makes.

I hope this helps.


"

hey, congrats on the purchase!!!

i personally am a big fan of the smart-fly EQ6TP power system. this gives you a turbo regulator to handle the voltage consistancy, a built in optic ignition kill, a power expander, and best of all.... servo matching capability on 6 of the channels!

you are perfectly fine with a 9100 and a123's if you choose, you WILL need to get equalizers or matchboxes for the ganged servos if this is the case. there really is no way to visually verify the matching without. if one of these servos is even the slightest bit off of the other in the ganged setup, you'll have massive battery drainage!

when using just one servo per elev half, you may very well want to use 8711's for the extra 70 oz/in of torque. i would also look pretty seriously at using atleast 3 servos on the rudder if you are using the pull/pull setup.

you'll find that everybody will have a different opinion with their answers to your questions. most of them will all be acceptable. this is kind of a nike/reebok, or ford/chevy situation. i have personally used products from duralite (powerbox systems), smart-fly and the 9100 direct route. i tend to lean towards the smart-fly setup i mentioned because of cost, dependability, and redundancy.

good luck in your endeavor! i'm sure you'll love the outcome whichever route you go down!

matt

Yup, what he said.

Thanks for the replies. I am leaning towards buying the plane with the AR9000 in it, and then picking up a Power Expander setup of some sorts. Hopefully Bob Ritchey will get a chance to check out my post and make a suggestion on exactly what I should grab. I like the idea of having the fiber optic kill switch and servo matching etc. As a side note for helping me choose what equpiment to grab, as I mentioned, the plane has li-ion batteries in it now and my thoughts were to use them since they are there, but if I was getting a plane without batteries already in it, I would grab a123's forit, so at some point either now or some point down the road I may make the switch. As far as the rudder servos, the popular setup seems to be just 2 servos on push pull mounted in the tail. Everybody says that seems to be plenty on this plane.

The 9100 setup would be lighter.
Best thing to do is get rid of any in-line switches. The Power expander and the 9100 will both do that.

Would the 9100 really be lighter in the end? I have also never dealt with match boxers for ganged servos etc, but it is my understanding that if I use a pwer expander with servo matching, that I can then lose the match boxes? Im trying to weigh out the benfits of each method. The AR9100 would be simpler as I could pretty much throw it in the plane as it sits now and go fly, and would also be cheaper just buying the reciver and being done instead of buying the AR9100 and Power Expander. That being said, if spending another $200-$300 will give me a better setup to protect my investment, I will go that route.

I have a 42% plane and its setup like this.

2 5200 LION on 2 switches.
1 matchbox per wing (they are in the wing)
1 matchbox for rudder

8611A's all around. 2 on each aileron, 1 on each elevator and 2 on rudder in push/pull. 1 8411SA on throttle.

I run the powerexpander pro and turbo regulator on 2.4 with the AR9000 and 2 satellites. I also have the SF optic kill.


Changes I'd make if I had to do it again.............maybe 1. I'd go with the EQ-6 for an all in one unit except that then I'd have to plug in 2 wires from the wing everytime I fly instead of one. But it would be cheaper to do the EQ-6 than 3 matchboxes, the reg and the optic kill seperate.

No need for a C-cup or any thing else. Of course I checked my surfaces with a H9 volt/amp meter to ensure they were not binding at setup.

Hi Todd,
For your setup I would recommend the AR9000 with a PowerSystem Eq6 Turbo Plus. The reasons are this. The AR9100 is fine when you have 1 servo per surface but when you have multiple servos per surface you would have to use Matchboxes or Equalizers. If you do this you are concentrating all the current the servos need into one lead. Something most people do not realize about digital servos is that they do not draw constant current. If they update at 200Hz then what happens is that the servos are updated every 5msec. What really happens is that the servo turns on the current for about 1ms and then turns it off for 4 msec. What this means is that if you use a meter to read the servo current draw and it says it is wanting 1 amp then in reality this is an average and what the servo is doing is asking for 5 amps for 1ms and 0 amps for 4msec. This means that when you have a Matchbox and 3 servos you are trying to pull 15 amps through your single lead for 1 msec. At 15 amps throught a standard R/C connector you can drop 1-1/2 volts or more. This means when your servo wants current your are starving it of voltage. This is why I don't recommend using Matchboxes or Equalizers on large planes. With the PowerSystem each servo gets its own servo lead. If you don't like hooking up all the aileron servos individually what a lot of people do is use a Multiplex green connector between the wing and the fuse. These connectors can handle high currents. The PowerSystem also isolates your receiver voltage from the servo voltages. The receiver voltage regulator takes it voltage directly from the battery inputs, which are Deans connectors and have much lower voltage drop than the connectors on the AR9100 at higher currents. The receiver in the AR9100 still takes its input power from the same bus the servos are running off. These are my thoughts from an engineering view point. If you have more questions please let me know.

This is the setup that I'm using.

AR9000 receiver
3 Hitec 7955's per aileron
3 Hitec 7955's on rudder (pull-pull)
2 Hitec 7955's per elevator half
2 Fromeco Kodiack switches for receiver
2 4600 mah A123 battery packs for receiver (With the A123's I don't have to worry about brown outs. The trade off is that I have to monitor milliamps used from the battery packs)
EQ 12 powerexpander with igniton cut off
I'm using the EQ 12 because I use the Hitec digital servos which I can program so I don't have to use matchboxes
1 2300 mah A123 igniton pack

This may be overkill, but it would really suck to loose a plane of this size due to a radio problem.

mr ritchey knows what he is talking about! and the support you get from SF is awesome! the eq6 is terrific!