DX7 Servo Issues

[doobeycat]

Having read the previous post in this forum, I have become slightly concerned about putting these digital servos into my new set up (Raptor 50).

Can anyone shed any further light on this issue and recommend what servos would an ideal replacement (please bear in mind I am setting up from scratch so money is tight!

Also I have been searching for the DX7 transmitter on its own but have not been successful. I know the receiver can be purchased alone but have yet to find the transmitter. So any direction would be much appreciated

Thanks once again for all your input, this website has been a great help in getting set up in this new hobby.

[Smoothound]

If you go into any shop or phone they will often do a price less servos or whatever. It is sometimes cheaper to just take the deal as is and sell on the stuff you don't want.

If you want digital servos Futaba 3152's would be a good choice but there are others, JR811's for eg. which can be had quite cheap but there are horror stories about them

[ChrisB]

The DX7 is a good price with the servos,,i have not used the supplied servos for a flight control but will gladly use them on throttle etc..

I can fully recommend the Futaba 3152 as a good all round budget servo

[Nutz]

For general flying with no hard 3D the servos supplied with the DX7 will be OK, they are around 5KG and 19sec/60°.
Compare with basic Fuatba spec servos @ 4.8V
Futaba S3001 3.2Kg, 0.23sec
Futaba S3004 3.00Kg, 0.22sec

You will be very lucky to find a DX7 set yet alone a DX7 TX by it self, I have been looking for one for my mate since Monday and most places are sold out until the end of the week (if were lucky).

[richieclarkie]

The concern isn't over the power of the servos, it's the shafts tendency to be brittle and break. During my 3D build two of the shafts broke away. You just don't know whether they will break mid air!

[ChrisB]

Yes Rich is correct,there are some bad stories of servo output shaft failure in flight,,

His snapped during the build

I wouldnt dare fit one on a cyclic control,i value my helis and my Boxer shorts too much

[moyesboy]

Its a pain that you have to take a set of crap servos with an excellent (apparantly) radio set.
They say these servos are "badged JR" so maybe there is a JR spare part that can be used to switch the dodgy shaft out?
If the shaft is nylon then it could be brittle and dry and need aging to take on its natural water content. this can be accellerated by boiling it in water - but if the parts have been a long time out of the mold its not that that is the problem.
Probably its acetal anyway for low friction in which case its crap quality material or a bad shape or got inclusions or voids from poor processing.

[robgt]

Crap servo bundling is normal in Tx sales as far as I'm aware.
Futaba seem to stick 3001 servos in their Tx bundles, and I wouldn't use them.
Might be ok for a complete beginner, but I still wouldn't recommend them for anyone flying a heli!

Cheers,
Rob

[doobeycat]

Thanks for all the replies to my query. I have gone for the DX7 with servos but will probably replace them with S3152's to avoid any potential problems in flight.

Mind you, having only just started out, it is unlikely I will have the helicopter off the ground that soon!!

[woody]

JR811's for eg. which can be had quite cheap but there are horror stories about them

Futaba seem to stick 3001 servos in their Tx bundles, and I wouldn't use them. Might be ok for a complete beginner, but I still wouldn't recommend them for anyone flying a heli!

If there was ever a thread to give me nightmares it's this one. Bet you cant guess what servos I have in my heli. The only good thing its got is a 401. I better go crash it sooner than I was hoping to so that I have an excuse to buy some better stuff.

[Ade_Law]

dont worry woody, 811 are fine. never had a problem used to use them on my raptor 50.

might want to ditch the 3001 on the tail for a 9254 tho

Ade

[Nutz]

I too have used 3001 up front (not on tail) and have had no problems with them, I will take what has been said about the Spektrum servos on board but I am still going to give them a try in a heli, that will be the only test to satisfy me. I know others have had issues but how do I not know it is not a one off.

[ross]

Possible Interference Spektrum Transmitters And Receivers.

An article in DEC 2006 ELEKTOR ELECTRONICS magazine (Pages 80 to 83) concerning Radio Control using WLAN ic's (Broadband and DSSS technology for Model Aircraft). . .

. . .writes of a test for interference and range carried out with the SPEKTRUM DX6 tranny and the recvr 1.5m above ground level separated by 800 metres with a RC car setup (a heck of a distance anyway). . No interference. However, as soon as the transmitter or receiver antenna was blocked by a human bodies ...the signal was blocked and the link lost altogether!

It would also appear that a problem can arise if several people are using the system at the same time, - as the tranny and rcvr use two of the 79 Chans simultaneously. Ok, the test was with a car RC setup but. . .

Sounds like a case for those modellers into electronics to do some testing!

[phil485]

been having a bit of a read. My interest was pricked with the news that futaba have startedreleasing 2.4 Ghz stuff. Came along a potentially worrying bit about the binding process. when the transmitter is turned on it seeks out other transmitters to work out what is free. If the two transmitter are just out of range or if one is shielded in a case or something, it could pick the same channels.
Not necessarily a problem at a small field, but I think they were worried by something like the nats where there are a number of different flight lines quite spread out.
just another thing to think about. Saying that I do pray every night that they bring out a module for my FF9, highly unlikely but I hope they can/do

[robgt]

The first major difference here (outside of the rc car issue) is that nobody should ever ever get between you and your heli while you're flying it.

If they do, they:
a) Have a death wish
b) Have escaped from the local loony bin
c) Both of the above

I don't know many people that can float either... so putting a human inbetween you and your flying helicopter might prove difficult

Finally, if you're flying 800 metres away from yourself, I'd suggest the heli is lost, or that you're name is Bob Johnston and you're up reeeeeaaaaaallllly high for yet another blistering auto

Cheers,
Rob