MiGBane

Thanks in advance for educating me. I've been away from RC for 7-8 years, so I missed the whole 2.4GHz revolution. I'm really feeling the itch to get out and fly this spring, but... My 72MHz Airtronics RD6000 TR and/or receivers all seem to have given up the ghost while in storage. I've tried new batteries and crystals in all and nothing is functional. I get a little servo jitter from a few combinations, but not much more. The TR was in for repairs a few times during its tenure, so I don't really trust it anyways, and I'm thinking about updating to a new 2.4GHz radio (and my fleet of 14 receivers to go with it). This brings on a slew of questions.

1. My planes all use Airtronics style (connector type and conductor order) servos. As I read reviews, ads and documentation for receivers, I see no mention anymore of the whole servo style compatibility thing. Is everything Futaba style clones now? Are receivers smart enough now to sense the servo style? I don't really want to tear up the wiring on 14+ planes to swap pins around in connectors and I'm opposed to adapters (doubling the number of interconnects rubs me the wrong way). How can I tell if a new radio system that I pick out today supports my old Airtronics style servo wiring? Does anything on the market now support them?

2. I see a lot of new brands in the radio segment that weren't around a few years back -- as well as a few notable absences. FrSky, Tunigy (I thought they just made LiPos) and Quantum are new to me. I know everyone has an opinion on what brand they like, and it isn't my intention to create a Dodge vs. Ford thread here. I'm curious to hear, outside of Futaba, what are the most apparently popular 2.4GHz radios at your club or field today? Am I missing any new brands that deserve a look?

3. I've done a little research on 2.4GHz radios, but haven't found a lot of good comparative data on the new guys or the current 2.4GHz offerings from those that were entrenched or emerging around the time I stowed my fleet. Simple things like apples to apples RF range, reliability (warranty claim data), battery life, and simple feature set comparisons seem to be eluding my Google skills. Is there a recent comparative review that I can look to for guidance?

4. I've never been a Futaba guy, and want to keep my TR under $250, with compatible receiver options ranging from micro/light weight (1/2A and ducted fan foam) 4CH up to 90/100 size 6CH sport nitro planes with suitable range for a large model. I'd like 4.8V, 6.0V, BEC compatibility in the receivers. In the TR I would like support for V-tail, delta wing, flaperons (3 position), exponential, mixing, flight timer (with audible alert), end-point adjust, throttle cut, digital trim storage, anything but AA battery power, support for 15+ plane models with ability to back up to SD card or PC -- sadly, these types of features don't seem to be much talked about anymore in the radio literature I've seen so far. Maybe all or most are just bread and butter now? If you have a radio system that meets the above criteria, I'm interested in hearing the make/model. P.S. I do not need drone/heli model support - fixed wing only.

5a. I notice that some 2.4GHz receivers have one antenna, and some two. Is that for antenna diversity? One for Rx, one Tx to support telemetry? Do the single antenna models perform as well as the dual?
5b. I also notice that different manufacturers use different receiver antenna types. Some appear to be base loaded coil, whip, PCB (IFA/ILA/patch?). Are they all pretty much a wash as far as performance goes?

Thanks again, for any guidance you can give.

tedsander

Here's a link to the most common connectors: https://www.servocity.com/servo-connector-types I assume from your post, you have the old "T" style. There is nothing to be done but start the task of moving pins around.
Everyone uses the Hitec/JR/Futaba styles for their systems, which all plug into each other. None support the old Airtronics wiring.

The major two brands in the US now are Futaba and Spektrum. Spektrum has its roots in JR, which is now gone. Frsky (a Chinese mfg) has become very, very popular with their Taranis line. Hitec is still very big in servos, but has faded with transmitters/receivers. Multiplex and Jeti (both with European roots) are gaining in popularity, but not near as big as the first two. There are several other brands (Turnigy, Quantum, etc.) of various asian origins, but are pretty minor (and in my mind, pretty suspect).
I'd look closest at Spektrum and Frsky, if you don't want Futaba. I personally have gone from Futaba to Frsky, and been very happy with the switch. Futaba and Spektrum give you pretty much the tradition RC systems, with varying levels of features as you go up in price . Frsky is based on the OpenTX world (although they ship with their own version of it, that can be replaced), that is a freeware software system for configuring radios. They sell different styles of radios, but all are pretty much the same on the inside, and in capability. Can be more of a learning curve for setting up than the other solutions, but gives an extremely versatile, extremely high end system. It is comparatively very inexpensive. I replace my multi-thousand $$ Futaba 14MZ with the $220 Taranis, and found it to be far, far more capable. They aren't as "solid" looking/feeling as a high end Futaba or Spektrum, but electronics and mechanicals are excellent. They will do everything you want, and much, much more. I would only buy from the authorized US distributor, Aloft Hobbies, and not some far east seller.
I don't know Spektrum very well, but I'd say it is by far and away the most popular brand in my area. You'll have to spend some online time researching their features, although you will find most of the mid-range and above will likely fit your needs.

I'm not aware of any comparison articles like we used to see in the old days.

Antenna type varies a lot between and within each mfg. As in the old days, the brands run different ways to implement 2.4Ghz, so once you get a transmitter, you are still pretty much locked into that brand receivers (if we ignore the Chinese rip-offs, like Orange, etc.). They all accommodate pretty much anyones servos. Antennas are dependant on the type of 2.4Ghz, and the intended use of the receiver, so not really a selection criteria for deciding which brand performs better. Futaba, Spektrum, Frsky, Multiplex and Jeti are all very solid from a performance perspective.

MiGBane

Thanks for the info Ted. Stay warm!

Skyhawk940

In todays radios, it depends on how far you're going to take it. Almost any 6 chan. radio system will work just fine and have enough features to fit your needs. If you want a high end, then you need to do some research to fit your needs. Your servos should work fine, but you may want to upgrade to digital servos also.

Skyhawk
Sandusky, OH

MiGBane

Thanks Skyhawk. What is the thought process behind the digital servo suggestion when upgrading to a modern receiver? My hangar has a mix of analog and digital, with digital on larger sport planes and analog on the smaller, lightweight stuff and models that don't require a ton of torque/precision.

MiGBane

I'm sort of leaning toward a Tanaris Q X7 transmitter. Based on a few YouTube videos that I found, it seems like it meets all of my requirements and the $105 price tag (and $15-30 for compatible receiver depending on channel count and telemetry function chosen) is really a great deal.

This radio has a USB interface. Does anyone that owns one know whether it is compatible/useable with RealFlight G3?

tedsander

Ummm...RealFlight G3 is really old.....
It might be useable, IF you have the old Interlink box from RF and it is one that allowed an adaptor cable to be plugged from it into the trainer port of the TX. And you have the cable with the right ends. No guarantees. Back in the day when I was building Ace MicroPro's and it's successor MicroStar, I got it to work with "off beat" transmitters. And the trainer output is still mostly the same as it was back in those days. But I'm unsure whether it would need adjustments to the pulse output and polarity, which aren't directly changeable for the trainer port of the Taranis. Never tried it with modern operating systems...but if you have G3 currently working with it's own Interlink, that shouldn't be a barrier. Wouldn't hurt anything to try.
Far easier would be to buy the current version of RealFlight (RF 8), where you don't need their box at all. Just use a USB cable from the TX to the computer. There is a pretty detailed thread on the Real Flight forums about how to set things up.
There is a pretty strong argument, though, to just buying the box from RealFlight, and save the wear and tear on your radios gimbals and batteries.

I think Skyhawk940's comment is related to your mention of using old Airtronics connectors, so he assumed reasonably that they were also very old servos. Sounds like you have a mix. No need for replacement or upgrade....unless you want to get fancy with using "sbus" setups, which allow more channels to be output, using a single connection. But the servos need to be capable of that, or there needs to be an adaptor down stream for them to plug into.

Skyhawk940

Just my thoughts about servos. Digital servos are more precise and have higher holding power. I know my real old analog servos would get dirty on the var. resisters and not be so dependable. If you don't need the digitals, I would still swap out the servos with new analogs. Sitting for 7 or 8 years is quite a while.

MiGBane

Thanks for clarifying -- and good advice. I was a little worried, reading into your comment and seeing all of the new SBUS, CPPM, I-BUS stuff on the market during my initial research, that I feared that I was also facing at a wholesale servo swap-out on top of receivers and Rx battery packs. I've done a lot more research now and see that the good ol' fashioned PWM servo interface is still around and available in receivers that work with the new radios.

bigedmustafa

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Airtronics is still being sold and serviced here in the United States under the manufacturer's Sanwa brand name. They have a nice 6-channel 2-4Ghz computer radio called the Aquiila:

https://www.amainhobbies.com/sanwa-a...30781a/p500037

Many 2.4Ghz radio systems can be very low latency and some modulation modes, like Sanwa's FHSS-3 modulation, can actually overwhelm some older analog servos. The Aquila uses Sanwa's FHSS-1 modulation, and should be compatible with any of your old servos that survived storage.

Extra receivers are quite affordable, and the radio offers powerful but simple programming features. Sanwa may not be popular, but it's a solid value and a reliable option.

MiGBane

So, update on my journey back...

Based on price, feature set, strong YouTube how-to video selection, positive review articles and helpful member comments, I took the plunge and bought a Frysky Q X7 radio along with a few V series (no telemetry) receivers. Tx was $105 and receivers under $20, plus I found a free shipping and 10% off coupon. While the radio ships with a 6xAA battery tray, you can run it on a 2S Lipo or LiFePo4 battery through the balancing connector. Receivers run on more or less anything you feed them too, 3V to 9V (HV versions). Binding the first receiver was a little painful, but I got the hang of it. I've set up a high wing trainer with expo, dual rates and throttle cut, and have servo centers and throws set up -- pretty easy, only took an hour or so first time. Next, I tackled an EDF foam jet with elevon control. The setup wizard chose the wrong direction for one h-stab output channel in the mixer, but that was an easy fix. The throttle trim feature caused me some pain as I could not get the throttle to register low enough to arm the ESC. Disabling T-trim fixed that up. No range tests yet as its windy, cold and snowing today. At least the groundhog said that the wait will be short.

Some other challenges resulting from storing my planes so long...
Have to install new Rx packs in all planes. Going with LSD 4.8V packs across the board. A couple of the little guys had 2/3AAA packs in them so they were a challenge. Most of my planes are big enough and have enough space for flat or square AA packs. Some of my NiCad packs are still semi-viable. I've been able to get maybe 80% capacity back on a few after charge/discharge cycles, but don't really trust them.

Two glow engines were really gummed up. I always used after-run oil and was pretty generous with it and the Marvel Mystery oil when they were put away last. Regardless, the carbs on both, the shaft bearings on one and the piston/sleeve on another were really gummy. Disassembled, de-greased with brake cleaner, cleaned, re-lubed and re-assembled. I probably should have replaced the bearings, but there is no play in them and they spin silently after the cleaning.

Rubber bands. The trainer uses those #64 bands to strap the wing on. They, including the ones that I had stored in my field box were brittle. Threw away and replaced.

Foam wing seating was squashed flat and the adhesive was weakened, letting it slide out of position.

Replaced fuel lines on 3 planes. I used blue silicon on everything but a few of the small line models had splits at the needle valve and muffle nipples.

Next project, check fuel tank seals. I've been putting pressure in them through the exhaust port while pinching off the feed line to check. Still a little worried that some of the older tanks might split due to the plastic aging.

At least I have things to do while waiting for Spring.

j.duncker

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I would not trust any RX battery pack that had been left flat for 7/8 years.

New ones are a very good investment.

If you go the lipo route make sure you have the specialist charger and consider some kind of fire resistant container. Make sure you can do a balance charge on any multicell lipo pack. Many people remove batteries from planes to charge.

Hydro Junkie

I have to agree with j.duncker.
I run 4.8 volt nicad flat packs and, even if I don't use them, I routinely cycle them so they are good to go when I do need them. The only pack I have that doesn't get cycled routinely is a 9.6 volt LiFe pack in one of my transmitters. I don't use it often but, then again, it doesn't lose power like most other types of batteries do.

MiGBane

Yeah, it was a sad day, throwing all of those old packs in the trash. I kept up on maintenance for a few years after putting them into storage, but got lazy as time progressed and paid the price. My field box battery bit the dust too.

Thankfully, I was flying a few LiPo-powered planes before taking a break, so I have a nice lidded earthenware pot for storage, LiPo charging bags, and a good (for the time) smart charger that can handle them. LiPo batteries didn't have balancing connectors and chargers didn't have balancing capability yet when I bought mine, but I did get a stand-alone balancer board that does the job just fine. LiFePo4 wasn't around then yet either so this charger doesn't support them. If I see a really compelling reason to use LiFe batts, I guess I'll have to upgrade my charger too.

Thanks for the advice!

b_gradinger

Im in the same boat. Planes in the attic for six years or so- planes ok, but I think all the batteries need to go. Servos? I'd like to think they're ok. Haven't upgraded to the newer transmitters- I'm assuming my old 72 futabas will do fine. Reciever replacement necessary?

tedsander

Unless the Futaba was really, really old when you put it away, except for the batteries themselves you should be just fine. You'll likely be the only one at the field with a long metal pole, hence interference/frequency sharing will be non-existent.
You may want to contact Futaba or Radio South to send your radio and receivers in for a check and tune-up, though. Things can drift a bit with age.

Hydro Junkie

That would be my recommendation as well. You might want to have the servos checked out too, just as a precaution. I've got a NIB high torque servo that I didn't use right away that actually went bad. When I finally did try to use it, it was totally dead yet, when I hooked up a different servo, that other servo worked fine, removing the chance of a bad transmitter or receiver

speedracerntrixie

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