Cheap radio systems for rocket gliders?

[GlueyFingers]

Given that prices of 2.4 GHz import radio systems are nearing the "disposable" range, anyone have experience using these in a rocket glider? The cheap micro heli intended servos are certainly small enough, and since those helis fly at an ounce or two total, the radio parts are well within rocket mass ranges.

Unfortunately the lowest price range systems don't do flaperon mixing, though one with a more expensive transmitter (and still dirt-cheap flight components) would. Or gliders with substantial dihedral could fly on rudder/elevator.

[rokitflite]

Yes...

[GlueyFingers]

Which is that? The linear servos make me think mCX/Vapor/Ember guts?

Are you flying with the "toy" transmitter or a full power spektrum tx?

[FlyBack]

-- Unfortunately the lowest price range systems don't do flaperon mixing,....

If you are just getting started in R/c, buy the most expensive transmitter you can afford. Trust me, you will grow into it. You can cut costs everywhere else but not on the transmitter.

Regards,

FlyBack

[GlueyFingers]

If you are just getting started in R/c, buy the most expensive transmitter you can afford. Trust me, you will grow into it. You can cut costs everywhere else but not on the transmitter.

Most models don't need those features, so the volume deals are to be had on the basic 4 channel sets (in my youth), or more lately of the included-with-airframe variety.

To get the value from a fancier TX for cheap models, you have to be able to buy cheap compatible RX's (or whole compatible systems and discard the TX).

I'd like to put the at-risk components, ie the flight pack, in the $30 range - which I think is do-able with today's dirt cheap import gear, just a question of choosing which.

The rc24 open source project based on the jennic modules looks interesting... potential for telemetry back down too. And rx-tx distance measurement for model recovery.

[rokitflite]

Which is that? The linear servos make me think mCX/Vapor/Ember guts?

Are you flying with the "toy" transmitter or a full power spektrum tx?


Vapor brick, DX6i radio :) .

[GlueyFingers]

Cool. Vapor bricks aren't exactly cheap though, being "name brand"... I'm thinking more along the lines of direct import stuff - hobby king, or even the spare walkera heli rx and servos I picked up.

[FlyBack]

I think we all would like a $30 flight pack for R/c rocket gliders. You have identified the problem. Receiver compatibility. All of the different 2.4ghz brands use their own protocols.

None of them are compatible.

For the Walkera gear you have, you would need a transmitter like the WK-1001 (http://www.ehirobo.com/shop/product_info.php?cPath=373_374&products_id=5770) or the WK-2801Pro (http://www.ehirobo.com/shop/product_info.php?cPath=373_374&products_id=6789). The cheap "disposable" transmitters that come with the helicopters only have a 10mw output. For full range you need at least 100mw. So, it's not about the number of channels or how fancy ... it's all about the POWER OUTPUT.

There is a reason why Spektrum is so popular for indoor and micro aircraft (and gliders). They have the widest selection of light weight 2.4ghz receivers and their transmitters are full range (more than 100mw power output).

So, even if you do find a cheap, light weight receiver you are still stuck buying a full range transmitter to use with it. That being the case, you may as well get one that has some useful features... like flaperons or elevon mixing.

Regards,

FlyBack

[GlueyFingers]

At the moment, no, you can't get a cheap DSM2 receiver -

But you can get a cheap full power 2.4 GHz import set

Or you can get a module to retrofit to an existing TX and change it to one of the import 2.4 GHz systems. Just looking at a TX module and receiver bundled for $29, additional receivers for $19.

My question was more if anyone had used one of these cheap (assan, corona, hobby king, etc) systems in a rocket glider, with equally cheap servos.

[GlueyFingers]

Hmm, so a corona 4ch 72 mhz RX is $15-$20, and micro servos are to be had for $5, so with a very cheap battery solution the $30 flight pack is feasable.

[tbzep]

I'm glad you started this thread because I'm behind the times with R/C gear. I have a Futaba 8UAF which was Futaba's flagship radio back in the day. (Got a heck of a deal on it when a guy needed some money fast.) I see that you can slap a 2.4 g module in it and jump into the world of spread spectrum. I haven't even looked at radio equipment in years other than to pick up a couple of tiny Berg receivers. This new stuff looks cool....but $300 for the module and Rx doesn't. :eek:

Where are you finding $29 Tx modules?

Edit: I see that Hitec's module will work with the Futaba just like their old frequency modules did, so that would drop the price by a good 50%. :cool:

[GlueyFingers]

The 2.4 GHz gear ranges from pricey down to dirt, dirt cheap. But each brand is proprietary and only works with itself. I think the $29 tx module and receiver combo was from Hobby King, have not tried dealing with them yet. The plus is that these are the same kinds of places you look for the cheap, light, but maybe not going to last too long tiny servos.

Hmm, a pack of motors may cost twice what it did when I was a kid... but R/C planes have come down so much in price. Used to budget $50 for the kit, $60 for glow engine and $100 for radio.... plus probably another $60 in incidentals. Now you can get a park flyer complete with name-brand 2.4g radio for under $100.... (what's too bad is that they want $60 for the receiver/2servos brick from it)

[CJU]

I've ordered a bunch of stuff from Hobby King - not the tx/rx stuff, but I have purchased a bunch of HXT-500 and -900 5 and 9 gram servos. They seem to work pretty well, but you do get an occasional reject (I've had 1 out of 20 with an issue). Order well in advance of when you need stuff, and if you do get a bad servo, it usually costs more than it's worth to return.

[GlueyFingers]

if you do get a bad servo, it usually costs more than it's worth to return.

Yes, that's my impression of this price class of stuff....

For servos at five bucks a pop easy to order extra, for radio systems a little less trivial.

Those parkzone guys have an alternate play on this with their brick pricing at sixty... it's almost twice what you have to spend for a receiver and pair of servos, but it's one ready to go lightweight piece with a brand name behind it...

[chanstevens]

One thing I've learned to watch out for in the radio gear is not to get too enamored by the Tx or its price, but pay more attention to the receiver options and prices. I borrowed a Spektrum Dx6i last summer, loved it. Digital trim, model memory, lots of bells and whistles, outstanding range, and retails these days for $150. The only problem is that the receivers, while also excellent and now available in many size/weight ranges, are easily double the cost of what I can still buy to match up to my clunky old FM Tx, and now thanks to decent synthesized receivers (ex. Corona) I don't even have to hassle with getting matching crystals. In my case, I hope to eventually have 15-20 r/c models in my fleet, and the Rx cost is much more a factor than Tx to me, but if I were more of a normal flyer and stuck with 2-3 models, springing for any of the mid-range 2.4 systems (Hitec, Futaba FAST, Spektrum) would be a no-brainer.

[GlueyFingers]

Yes, the pricing of the corona synthesized receivers make staying on 72 MHz tempting.

Though the pricing of their version of 2.5 GHz is not noticeably higher once one spends thirty bucks or so on the TX module. Decisions decisions...

[kevinj]

When you buy cheap gear you tend to get what you pay for. I've had a couple of bad crashes (read that as totaling the glider) because of being cheap in the gear (servos for the most part).

kj

[GlueyFingers]

When you buy cheap gear you tend to get what you pay for. I've had a couple of bad crashes (read that as totaling the glider) because of being cheap in the sear (servos for the most part).

I guess it all depends on where the cost and risk are.

If you are going to put a lot of effort into building the airframe, and your flying site is one where the likelihood of recovery is quite good, invest in quality radio gear.

If the airframe is a quick foam and tube job, and you aren't airstarting any engines, and there's real risk of non-recovery, then the radio gear should be very cheap - crashing due to a failed servo or RF link is neither the greatest risk nor any great loss.

I'm thinking of putting the actuator control from a radio shack plane on the rudder of a readiboard dihedraled sky dart... "radio influenced" free flight if you will.

[rokitflite]

Buy the cheap stuff! Just make sure you take lots of pictures/video to post on the forum! :D