[Andy W.]

I have some newbie questions about receivers. I am collecting the electronics for two park-flyers. I would like to use the same receiver in both of them, as well as other future planes. One plane needs 3 channels (ESC, E, R), and the other needs 4 (ESC, E, R, A). I have a Spektrum DX5E-DSM2 transmitter, for my trainer plane. I want to use it with my park-flyers. What receiver(s) can I use in them? Do I have to stick with the Spektrum AR500, or can I use something else? Does it have to be a 5-ch receiver? I would like to use a smaller/lighter receiver. Any recommendations?

Below are the spec's for my two park-flyers. I would like some help choosing the right components.

PF#1 (3ch hi-wing tail-wagger)
fly weight= 6-8 oz.
wingspan= 35.5"
W area= 192 sq.in.
length= 24.0"
motor= E-flite Park 250
ESC= Thunderbird 9A
servos= 2x Spektrum S75
receiver= ?

PF#2 (4ch Biplane)
fly weight= 26-28 oz.
wingspan= 32.25" top, 31.25" bottom
W area= 315 sq.in.
length= 26.5"
motor= Cobalt 400 27T (came w/the plane)
ESC= 30A recommended (Mfgr?)
servos= 2x 6g. + 2x 9g. recommended (Mfgr?)
receiver= ?

The items in red are items yet to be acquired. What do you recommend I get? Do you think any of the items I do have are inappropriate?

Thanks, for your replies, and let me know if you need any other information.
- Andy W.

[Andy W.]

Oh, and any recommendations on batteries would be nice too. Preferably 2 or 3 cell LiPo's.
- Andy W.

[daniel]

Your DX5 can talk to any of the current Spektrum receivers. If there is more than 5 channels on the receiver, they are "wasted" and won't be receiving a signal... but there may be a reason to use one of the better receivers - the AR500 is designed for park flyers with low power usage... but if it's up to the task of flying the Apprentice, it should be fine in things about that same size, or smaller. It is not a good idea to actively swap a receiver around between planes - the little plugs get worn out and eventually they won't make a reliable connection - there's other issues with doing that too, but this activity puts a lot of mechanical stress on the receiver, and they aren't built for that.

Personally, I like to use the best stuff for servos and ESCs and all - because really, the life of your plane is depending on those parts, and while I can emotionally handle a crash that I caused, receiver lock outs, broken servos, and other parts failures - really pisses me off. It is hard to say what the "minimum" servo would be in some cases - on the lighter of the two planes, the S75 should be fine. On the other one, it's hard to say - that's a bigger biplane, and if there's things like 4 ailerons going on, then you have to move a lot more weight - each aileron servo would be moving two ailerons and a bunch of linkage... so maybe a micro servo like an HS55 isn't going to work.

One more thing - the Cobalt is a 200-watt BRUSHED motor... this means it may be hard to find an ESC for it... now... here comes the math

To get 200 watts on a 3-cell (11.1V) battery, your ESC and battery can be a little less - 200 watts / 11.1V = 18 amps (which the motor can handle just fine)

To get 200 watts on a 2-cell, your ESC and battery will need to handle a lot more current - 200 watts / 7.4V = 27 amps (which the motor can not really handle for extended periods)

Basically this means you'll probably need to run 3-cells, and an Electrifly 25-amp ESC (Electrifly is about the only option you can get locally for brushed ESCs), and you'll need a battery that can handle 25 amps or so... you will probably need different batteries for each plane. Come by the field some time and I'll show you my collection of batteries and why I need each different size. A lot of them can be used in different planes, but some are too heavy for some planes, some don't handle the power requirements of other planes, and so on...

It would probably be beneficial to convert the Biplane to brushless power... and it would be easier to find parts that match up. Might even be cheaper.

[Andy W.]

E-flite has a 30A Mini 'Brushed' ESC for 400-600 speed motors, and will handle 3.5 to 9 V power. The mfgr recommends a 7 cell NiCd battery. I am going to try to locate an equivalent 2 or 3 cell LiPo.

As for receiver(s), I believe the one to use is Spektrum AR6100, AR6100e, AR6110, or AR6110e.

And as for servos, I may stick with Spektrum 6g and 7.5g units. What is the difference between standard and digital servos?

[daniel]

Andy W., on Sep 5 2009, 07:43 PM, said:

E-flite has a 30A Mini 'Brushed' ESC for 400-600 speed motors, and will handle 3.5 to 9 V power. The mfgr recommends a 7 cell NiCd battery. I am going to try to locate an equivalent 2 or 3 cell LiPo.

You need an ESC with Lipo protection - this is pretty important, or you risk running the Lipo down too low, and then it won't charge any more. Lipos are 3.7V per cell, so there's not a way to make a 9V. They charge up to 4.2V per cell, and you can run them down to 3V per cell. At this point, a proper ESC will shut down the motor and you will retain control of the servos to land.

Quote

As for receiver(s), I believe the one to use is Spektrum AR6100, AR6100e, AR6110, or AR6110e.

Those are 6 channel receivers, and they will work, but you will be paying extra for the channel you don't need.

Quote

And as for servos, I may stick with Spektrum 6g and 7.5g units. What is the difference between standard and digital servos?

The little Spektrum servos might not be strong enough for the biplane - this can result in stripped gears in the servo and loss of control. The difference between digital and analog servos is slight - you won't notice it on most airplanes - they both work with the same input signal, and the difference is how the servo moves between updates from the receiver. There is more explanation on various articles you can find with a simple Google search. You won't need digital servos for light airplanes, and all it will do is increase the power consumption. Note: the Spektrum digital servos are digital in the way they handle signals, but they do not accept the higher update speed that has become standard for digital servos, so they will not seem any faster. IMO, those Spektrum servos aren't that good... Hitec is much better.

http://forums.parall...ch.aspx?a=11634

[euronse09]

Yep, they fit stock perfectly fine with no CG issues. Just put them on the battery plate pretty far up just about against the servos. Do you have a 60amp esc? Cause between the -6 and these batteries, a 60 amp esc will be able to deliver the power much safer. I wouldnt trust a 45 amp to take it for long. The -6 is rated for 52 amps continuous, and will peak a bit higher.

[hyperdyne]

I would really, strongly, imperatively, advise against using the AR6100. They are NOT full range receivers and as such you will get lockouts quite easily. I know firsthand, crashing over 5 planes due to "death by 6100". It's not worth it. Some people may claim they have great luck with them, but IMO they are on borrowed time. The RF link is nominal at best.

The AR500 is better since it is a full range receiver. Now you probably know why spektrum just released the AR500 (and why it is used in their bind and fly models), since the 6100 is such a wart on their product line. I ended up changing out any 6100s to 6200s and all was fine. But if you dont need 6 channels and a remote receiver the 500 should be the way to go.

YMMV.

[JoeSantora]

And by the way. The trainer switch will control a 6th channel if you use a 6 ch reciever.

[daniel]

hyperdyne, on 22 November 2009 - 07:57 PM, said:

I would really, strongly, imperatively, advise against using the AR6100. They are NOT full range receivers and as such you will get lockouts quite easily. I know firsthand, crashing over 5 planes due to "death by 6100". It's not worth it. Some people may claim they have great luck with them, but IMO they are on borrowed time. The RF link is nominal at best.

The AR500 is better since it is a full range receiver. Now you probably know why spektrum just released the AR500 (and why it is used in their bind and fly models), since the 6100 is such a wart on their product line. I ended up changing out any 6100s to 6200s and all was fine. But if you dont need 6 channels and a remote receiver the 500 should be the way to go.

YMMV.

On what kind of plane was this? The range is primarily affected by the transmitter power, and the main issue with Spektrum receivers is power problems. The 6100 can not run a set of full size servos, but the range on it is fine. The 6200 is a little better because it has the remote, which helps the user overcome placement issues, and it can push more amps which helps the user with power issues, but a properly installed and properly place 6100 should have the same range as any other receiver. If it can see the signal, it will work, and the ability to see the signal is related to antenna exposure and signal strength - antenna exposure is improved with the remote receiver of the 6200, but signal strength is only affected by the transmitter.

So I would question whether you had an actual range problem, or whether you had a shadowing problem or power problem with the 6100. I run plenty of 6100s, but I run clean power systems and only use them on small servos, and I haven't had any issues except one where I know I had a power drop.

[Steve Eiche]

Here is my recommendation. If you are now pretty sure that you are going to stay with the hobby, I would invest in a radio system. The DX5 is OK for a single plane, with limited functionality. It has no timer (VERY important for electrics), it uses regular AA batteries (which will be annoying to replace often), no model memory for multiple models, etc. If you already have the DX5, use it, but I would HIGHLY recommend a DX6i. That radio will work for you up until you get into fairly complex models. The cost is reasonable, and you can often find them for sale used in the online forums for a really good deal.

Personally, I started with a Futaba 6EX FASST, Futaba's six channel spread spectrum radio. I have never had so much as a glitch that I could attribute to the FASST system, so I am happy with it. Now I am using a 10C, and it does just about anything that I can want a radio to do. That said, due to the receiver options available for Spektrum, I think that is probably the way to go for people starting out. The receivers are cheaper, and they have sorted out the issues that they had with some early receivers. As long as you have the latest firmware in the receivers and good power to them, there is no reason that you should have issues with any of the receivers. If anyone has more than one crash due to a faulty receiver, they shouldn't fly it. Period.

As for the planes, I would take a look around on the rcgroups.com and rcuniverse.com forums for recommendations. You will learn a lot. I would stay away from brushed motors, and probably even replace them with brushless power systems in planes that came with them. In fact, I did exactly that in the Multiplex MiniMag trainer that I am selling in the For Sale forum. It came with a small brushed motor, but no ESC. Instead of using that, I got a decent brushed motor with lots of power and excellent efficiency. Places like hobbyking.com have decent brushless power systems at prices that eliminate the need to even consider using a brushed motor. In addition, if you start with a decent motor and ESC, you can always use it in another plane. I can guarantee that you are not going to want to put that brushed motor in anything else.

[hyperdyne]

Several planes - 2 strykers, p-51, spitfire, etc. Range is a function of Tx power, but I am not sure if you have a handle on the intricacies of receiver design. The 6100 no doubt has a worse front end. The 6200 has a remote receiver, but that only helps with multipath. My setup was pretty simple and the planes were not very far out. I disagree on the range, the 6100 is not listed as a full range receiver. And servo drive is related to battery only, not the receiver. The Rx doesnt have anything internal to regulate the battery going to the servos. I am not sure what you mean by the Rx being able to "push more amps".

The power system I used was the same with a 6100 and 6200. No real issues with power dropouts. It was certainly the 6100 RF link that was the problem. Things like shadowing, as you put it, are actually multipath issues that dont cause absolute failures like I've experienced (maybe a hold here and there).

daniel, on 02 February 2010 - 11:47 PM, said:

On what kind of plane was this? The range is primarily affected by the transmitter power, and the main issue with Spektrum receivers is power problems. The 6100 can not run a set of full size servos, but the range on it is fine. The 6200 is a little better because it has the remote, which helps the user overcome placement issues, and it can push more amps which helps the user with power issues, but a properly installed and properly place 6100 should have the same range as any other receiver. If it can see the signal, it will work, and the ability to see the signal is related to antenna exposure and signal strength - antenna exposure is improved with the remote receiver of the 6200, but signal strength is only affected by the transmitter.

So I would question whether you had an actual range problem, or whether you had a shadowing problem or power problem with the 6100. I run plenty of 6100s, but I run clean power systems and only use them on small servos, and I haven't had any issues except one where I know I had a power drop.