abufletcher

Thanks for the clarifications. I think all I really want/need is the BatShare. Unfortunately, even though it's only $30, international shipping to Japan would be an additional $45! I think for now I'll do without. And maybe order one for the next time I'm in the US (next February).

speedracerntrixie

My Feedback: (29)

Although I use and recommend the Smart Fly products, I don't deem the Batt Share as something that is a must. It's nice to have as I found with it my batteries would discharge almost identical. Useful tool if one battery starts taking more current to top off then you would be aware of a possible issue.

abufletcher

OK, I just have to ask. What's the deal with the DEANS plugs on the SmartFly products? I've always thought of those as something strictly for electric models (and frankly I hate them).

pedroaleman65

Hi Abu, important to me seems the use of metal gears at any control surface. But I am sure, you knew that. The throttle servo can be plastic or carbonite gear, but choose a good one, not the cheapest. Sometimes the protection against vibrations is not made accuratly.

I never had any plane with dual batteries. I learned soldering at Bosch, where I was trained as an industrial mechanic. Therefore, I can rely 100% on my work, doing all the electric stuff myself.

Now, in the digital age, I came back to 4 cell Nimh batteries. The servos are so fast and strong, that this is absolutely enough. Even for me, sometimes doing 3D and moving huge ailerons.

The new generation of Nimh-cells, such as the sanyo eneloop or the panasonic evolta are found at the supermarket. They stay charged for quite a long time. The package has to say "Ready to use" !!! Of course you need the skills and the strong tool to solder them. But I saw enough crashes with rubbish-batteries bought from the modellers-shop.

In my profile you find "Raudilio grande". This machine weighs 8 kilos, has a DLA58. The RX-battery is 2x4cells Panasonic evolta. They are soldered parallel. So, the capacity has doubled to 4000mah and also max current power to about 20 Amperes.

I dont use a switch. I connect the plus wire with a bridged Deans-Plug. You know that system and the power, needed to connect them. Gives you good safety.

The servos on ailerons and rudder are Graupner DES 707. Look at the specs. They are strong, not too fast and have a very low consumption of energy. I can do 30-40 flights of 15 minutes, if I want to. And look at the price!!!

Both elevators work with Hitec 5485HB, Don`t use them in your plane. Not because they would be bad!!! It is just because I have huge aerodynamic compensators. So they are not stressed with pulling really hard or by the vibrations of the engine. I guess they would do on your elevator, but I do not know the size of the surfaces.

The "switch" and the sanyo evolta RX-battery. The female part sitting in a plywood tray and locked with a piece of white plastic tube.


Pedro

abufletcher

Here are the specs on the Futaba 3305 servos I plan to use:

pedroaleman65

Yes, this will work for your purposes. It is slow, but therefore you won`t need expo to get your plane smooth. What I can recommend you to do is, use the Multiplex gold connectors to connect your ailerons. Don`t take the normal servo connectors. Secure the cables to the MPX with hot glue against vibrations and to have a grip.

BarracudaHockey

My Feedback: (11)

Pedro, glad you're having success with 4 cells. I personally would never do it with modern radio systems due to 2.4 systems being less tolerant to low voltage conditions but if it works for you.

speedracerntrixie

My Feedback: (29)

Agreed, I would not ever install less then 6V RX pack with 2.4 in anything.

pedroaleman65

It works really good. I fly a futaba FX18 radio converted to 2,4 GHz with an ACT module. Transmitter and receivers are doubled systems. Means, not only two antennas on the receiver, but two receivers working and comunicating as one. This receivers work down to 3 Volts, like the old futaba receivers did. And their new 2,4 types.

What I heard over the years, was that the old Multiplex-receivers were really delicate, when the voltage dropped under 4,8 volts. But this was before the 2,4 era.

With five of these cells, charged fully, you need a regulator. Until the peak drops down, you reach almost 8 Volt. And the nominal will be at around 6,5 Volts.

I keep everything as simple as possible and therefore I don`t want to use even a regulator. As some of you said, keep the sources for problems to the minimum.

And the modern, ready to use Nimh cells come with a higher nominal voltage. With four cells you come out at around 5,3 Volt.

Flyfast1

My Feedback: (1)

Would you please explain more about your two receiver setup and how it works?

Thanks,

-Ed B.

vertical grimmace

My Feedback: (1)

Keep in mind Abu, that many of these items were originally developed for the IMAC/3D aircraft with lots of ganged servos, and large power requirements. You will see many of the battery connectors are in fact Deans style, which are geared toward heavier current.

The "Power board" is very useful when lots of servos are used on 1 channel.

So, with that said, it is important to think about what your requirements are. If you are just gonna scale fly around the sky, and your plane does not have a lot of servos, the original point of 2 switches, batteries, should be fine

thumbnstick

My Feedback: (169)

KISS ... keep it simple stupid. Paid money to learn that a long time ago in college. Paid money to learn it too. Dual batteries are a good idea. I do it even in my Jets. No power boxes. Two switches, two plug ins and one battery voltage indicator, plugged in or Y'd in the Rx outlets. You can use a simple inexpensive LED light bar to read voltage..... while you move the servos around, on the ground you can see the voltage drops with the servo movements. It gives you a simple way to show how your RX and servos are effected by current draw. Turn one switch on and check it, turn that off and the other on and check it, now both on and check it. Simple. Remember, With dual packs, if one goes bad, it will pull the other down. If you are at the field and one pack is bad or not fully charged, you have the option to fly with one pack.

speedracerntrixie

My Feedback: (29)

Depends on the airplane. A 150cc 3D airplane is going to draw much more current then any jet or sport airplane. Keeping it simple is always a good idea but you still have to match the equipment to the airplane and expected performance level. Sometimes this means more equipment in the airplane.

pedroaleman65

Okay Ed, but don`t expect too much from a mechanic...... As I said, there are two receivers in one housing or in the lighter versions without the housing but a shrink tube. You do not have kinda satellites like the spectrum system. Therefore less cables or connectors that could be sources for problems.

The antennas you position in a right angle. So you have the best conditions for receiving the signals. The receiver with the strongest signal is taking command of the servos. It depends on the flying position of your plane.

The antennas of the transmitter are positioned the same way. Yes, and here are also two transmitters working in one housing. The power is therefore 2x100 milliwatt not only 100.

There are quite some systems like mine on the market. Weatronic for example or Yeti duplex, I think goes the same way. Some of the Jet-Pilots rely only on this systems.

Pedro

acerc

I base a lot of what I do from what I see and whom I talk with at major competition events held here such as Top Gun, Monster Planes, Florida Jets. And I have yet to see one plane with nothing but two batteries and two switches going to the Rx. If it is anything more than a 50cc, more than one servo per surface, high voltage, and lots of money you can bet your sweet petunias there is some form of power board on board. But for the smaller cc's, fewer servos, lower voltage, I agree it is not necessary or needed.

But then on the other hand I did fry a Rx on a 26cc profile with standard everything, just wasn't up to the power of all the servos going ape sheet at the same time under load.

pedroaleman65

Yes, you are right.... No one will go to to the TOC or Joe Nall with my simple equipment, these machines really require another setup

speedracerntrixie

My Feedback: (29)

Right you are Pedro. A regulated system is really needed at that level. The top guys need to have servos running the same speed and power whether the first or last flight of the day. I would like to think my 40% Extra is capable even if I'm not LOL

Flyfast1

My Feedback: (1)

Pedro,

What is the device that the two receivers are connected to that switches to the receiver with the strongest signal. Sorry if I missed something here.

Thanks,

-Ed B.

abufletcher

Since my only goal with the P-56 ARF is to get to know how my Seidel-UMS 770 operates (and operates under actual flight conditions), I won't be doing anything fancier than a slow loop, barrel roll, or an Immelmann. The Sopwth Strutter this engine will eventually go into won't even be doing that. I don't fly at shows (and the club field is empty most of the time) so the chances of damaging anything besides the model (and my pride, and of course my wallet) is minimal. I've got heavy duty, metal-gear servos (Futaba 3305), heavy duty twisted servo extensions, and two brand new 6.0V 2000mAh NiMh battery packs.

So for my purposes the simple dual battery/dual switch system into the Rx should be enough for right now. Later on, I'll add the BattShare or something similar.

drac1

My Feedback: (4)

Yep, same here. I use 2 batts plugged directly into the receiver and they both draw evenly.

abufletcher

That seems a little extreme. Nowadays the vast majority of RC flyers now fly with 2.4 radios and the vast majority of them are using simple 4.8V Rx packs. But, of course, the vast majority of modelers aren't flying enormous models. Personally, I've used 4.8V packs with 2.4 radios for over 5 years...but it's all been 50-class 4st models.

Boomerang1

Yes, that's what I'm using at the moment too. But it's important to remember the limitations of these cells. These batteries in the AA size have a limited current delivery capability,
As you can see by the discharge curve they maintain their rated 1.2 volts through most of their discharge up to about 2 amps. Two battery packs would give you 4 amps max.

Some jets using really powerful servos on all-moving tails or large gas powered 3D aerobatic models with ganged servos max exceed this & drag the battery voltage down under
extreme loads to dangerous levels.

But for 99% of 'average' models (like I fly) no problems at all. - John.

speedracerntrixie

My Feedback: (29)

Quite so, then again I started using 6V packs well before 2.4 hit the market. It was a good way to get a bit more power and speed out of the servos. I just carried the practice over when the 2.4 stuff came out. Lots of guys that were having issues with the early Spektrum stuff was using the supplied 4.8V battery. I never experienced the same issues with my 6V packs. However you are correct as even then the smallest airplane in my fleet was 1.2 powered. Even now with the pylon racing I have been doing the airplanes are fairly small ( 64" span ) but are powered with a YS 115, have electric retracts and travel well over 150 mph I use LiFe 6.6V batteries and have had zero radio issues.

pedroaleman65

My dear friend Ed, you brought me to the limit now.

My receiver is a divercity system uniting the electronic pieces of two receivers on one plate. I really cannot tell you what that piece is called, switching to the receiver with the better signal. But it is not an external device, it is also sitting on the same plate.

Klaus Westerteicher from ACT-Europe could tell you that. He worked for Multiplex and Robbe/Futaba before he sold his own products.


sorry, if my knowledge is not that big

Pedro

pedroaleman65

These are not evolta or eneloop. If the diagram shows an AA or Mignon size, it must be an old type. The new AAA or micro size could give you 3-4 amps. If my AA were that weak, all my machines come down.