This ad space is available now!

Your Reviewer

Please Donate

All of the products reviewed here have been bought with my own money and nobody pays me for the time I spend writing these articles.

If you find any of this stuff useful and/or would like to see RCModelReviews continue to publish material like this then please consider making a small donation towards the operation of the site.

 

My Credentials
So who's doing this reviewing then?

Well I've been building and flying or driving radio controlled models for over 40 years and during that time I like to think I've built up a reasonable amount of knowledge.

I'm also a qualified electronics engineer who has worked in radio frequency, analog, digital systems and software for more than three decades. In fact I designed and built my first RC set back in 1969.

For the past nine years I've also been involved in the design and manufacture of some rather sophisticated engine technology and UAV flight control systems.

So, chances are I've been there, done that and have a huge pile of tee shirts to prove it.

Right now I'm heavily into 3D flying and enjoy all aspects of the RC hobby. I may be old but I don't feel it.

In the Pipeline

Here's just a little bit of what's to come on this site...

RC explained: Demystifying terms such as PCM, PPM dual conversion, single conversion, full-range etc., this feature will explain it all.

Cheap Chinese Engines: Just how good are those cheap Chinese glow and gas engines that sell for half the price of their "brand-name" equivalent? I put several to the test.

Build your own radio gear?: Back in the old days, building your own RC gear was not uncommon and now the arrival of 2.4GHz has made it practical again.

 

Feature: Telemetry, the next "big thing"?

NOW YOUR PLANE CAN TALK BACK

Dated: 24 Mar 2010

For decades, most model-fliers have been more than happy to enjoy a reliable RC link that allows them to control their model while its in the air and in that respect, our RC systems have come a long way.

Back when RC flying first started, equipment was bulky, heavy and unreliable. However, transistors eventually replaced tubes, superhet replaced superregen and today we have some very hi-tech gear in the form of spread-spectrum 2.4GHz radios and receivers.

Surely this is the pinnacle of RC equipment, right?

Well it would seem that the RC makers still have some cards up their sleeve and the next ace to be played is telemetry.

What if your radio control system not only gave you the ability to direct your model around the sky but also reported back exactly what that model was doing and how the onboard systems were functioning?

Suddenly things get a whole lot more exciting and new possibilities open up.

Telemetry has the potential, not only to improve the safety of our models by monitoring battery voltages, fuel levels and other critical parameters, but it also creates other opportunities to get even more fun out of flying.

Imagine being able to tell instantly exactly how high, how fast and how far away your model is flying.

Think of the benefits to be had from alarms that will sound to warn you when there's interference about or if your receiver battery is running unexpectedly low.

That's the world of telemetry and now there are a growing number of "off the shelf" 2.4GHz radio systems that deliver on that promise.

What's Available?

A few years ago, a US-based company called Xtreme Systems told the world that they were about to release a revolutionary spread-spectrum RC system called XPS that would include telemetry.

This, they told an eager audience, would include a kind of telemetry dashboard that would attach to your transmitter to display all manner of information beamed down from your model in real-time.

Sadly, but not unexpectedly given the track record of the company's founder, this realtime telemetry and display screen have failed to eventuate -- but others have already begun to deliver what, in the case of XPS, remains an unfulfilled promise.

The first to really roll-out a telemetry-enabled 2.4GHz radio was Jeti. Their bi-directional 2.4GHz system can provide the flier with a range of useful (some say essential) information about what's going on in the model while it's flying. So far, users of the Jeti system seem very satisfied with the product but unfortunately I don't have one to test or comment on.

Recently Hitec also announced that their AFHSS 2.4GHz system would include telemetry capabilities, and it does.

When coupled with the feature-filled Aurora 9 transmitter, the Hitec system provides a version of that telemetry dashboard we were promised for so long by XPS. At a glance, you can see exactly what your receiver voltage is and set alarms to warn you if it drops too low. There are also plans to deliver a range of sensors for airspeed, GPS, altitude, RPMs, etc.

Even those who upgrade their Futaba or earlier Hitec radios to the AFHSS system will benefit from this telemetry, the module being capable of screeching different warning tones for the basic alarms, regardless of the transmitter it's installed in.

There is a video review of the Hitec system on the RCModelReviews YouTube Channel

Watch for the full review of Hitec's AFHSS system appearing on RCModelReviews.com shortly.

More recently, Chinese manufacturers have also started entering the telemetry-enabled market. FrSky, whose existing FHSS system scored extremely well in my review have sent me a pre-release version of their system, which I'll be testing out shortly.

FrSky's approach is somewhat different to Jeti and Hitec. Instead of integrating the battery alarm, they've simply provided users with a bi-directional connection between transmitter and receiver. There are two analog inputs on the receiver that can be used (with the addition of suitable hardware) to measure almost anything (voltage, current, airspeed, altitude, etc) and a digital RS232 interface that could be used for the transfer of other data -- such as GPS info.

At the transmitter end, the system can be configured to alarm on predefined levels of the remote analog inputs and there's a serial-out connection for the digital data stream.

I'm hoping that FrSky will publicly release the specifications (and pretty sure they will) that allow DIY enthusiasts and other manufacturers to create a raft of different sensors for the airborne end and displays for the transmitter end. Although the FrSky offers the least turnkey capabilities, it does have the maximum potential.

Who needs telemetry?

Having read this far, you might think I believe that telemetry is indispensable but you'd be wrong.

The big problem with telemetry is the potential for overkill.

Flying an RC model requires you to keep a constant eye on the model itself. Often, glancing away to look at a display can result in disorientation or simply being unable to find the model when you look back to where it was before.

For this reason, some information such as RPMs, speed and even altitude can be more trouble than they're worth. Imagine you're trying to see how high you can fly -- climbing until your model is a tiny spot in the sky. You look down to see exactly what the altitude telemetry is saying and when you look back -- that little dot is gone.

Even the use of audio-alarms can be problematic.

Have you ever stood in a busy flightline and heard a transmitter (just like yours) start beeping? Was it yours? Why is it beeping? Once again, you sometimes have to look away just to be sure.

But I'm not entirely negative either -- telemetry certainly has its place and for some kinds of model flying it will be indispensable.

Many model-fliers are required by law to remain under 400 feet of altitude, something that's pretty hard for most to estimate by eye. Set an alarm that sounds when your model reaches 350 feet or so and you'll never risk flying too high again.

A low-battery alarm should never be activated if you use the right batteries and care for them properly -- but sometimes things do fail and if that alarm sounds it might just save your model.

Likewise, if your model starts getting hit by interference, it would be very nice to be alerted to this fact before control is lost -- thus giving you the opportunity to land before it's too late.

So telemetry is good.

Over coming weeks and months, I'll be taking a closer look at telemetry and trying to review each new telemetry-enabled system as it comes on the market. There'll also be some DIY projects based on FrSky's upcoming system for those who are keen to do some tinkering.

Related links

Fresh Articles:

Privacy Policy

 

YouTube

 

Join the Forums!

Discussion Forums

 


The Blog

Updated: 20 Sep 2012
Here's a blog that will keep you informed just what's going on behind the scenes at RC Model Reviews and also tells you a little more about myself.

How compatible are 2.4GHz RC systems?

23 Mar 2010
How come there's no compatibility between different brands of transmitters and receivers? Why can't you use a cheap Chinese receiver with your Futaba FASST radio?

How to get a product reviewed here

4 Mar 2010
Since this has become a very frequently asked question, I've posted this simple guide to getting your product, or a product you're thinking of buying reviewed here at RCModelReviews

How servos work

Useful information on what's inside your servos and how they work.

The Good Oil

Important facts you should know about the oils that are used in our model engine fuels.

Heads-Up: 2.4GHz RC systems tested

How well do five different 2.4GHz systems stack up when hit by interference? The answers are here, with more to come.

Review: Bushnell's $80 Speed Gun

Yes it does work on model airplanes but there are some limitations involved with this bargain-basement radar speed gun.

Review: TowerPro MG995 servo

These are possibly the world's worst servos, find out exactly why you should avoid these boat-anchors at any cost.

Review: SK90

2.4GHz

It's cheap but can it really stack up against other glow engines in the .90 market? Find out in this review.

Review: iMax 9X 2.4GHz radio

How does this cheap 9-channel 2.4GHz radio system perform when compared to big-name systems that can cost two or three times as much? Have the Chinese finally developed a real contender with the iMax 9X?

2.4GHz Explained

Does all this 2.4GHz stuff have your head spinning? 2.4GHz

I've done my best to demystify the whole subject so if you feel like a bit of learning, this is the stuff for you!

Fix That Engine!

How can you tell when your engine needs new bearings? Who has the best prices and service on replacements? Just how do you change them? Get all that information and watch a great video tutorial anyone can follow.

Chinese Servos - How do they stack up?

Servos

The Chinese are now churning out a huge number of very reasonably priced no-name servos. But are they any good?

Baffled by batteries?

Batteries Nicad, NiMH, Li-Ion, LiPoly, LiFePO4, A123... the range of different battery types has never been greater. So how do they differ and what type should you be using?

Possibly useful: