rabraaten

I am rebuilding a Hangar 9 Arrow into a low wing plane. The reconstruction means that the servo tray is moving up into the fuse a bunch and the servos will now be installed inverted. I'll be using the same transmitter (JR Sport S400) and would love to avoid the hassle of removing my battery and switching the servos in the radio. Is it possible to switch the wires in the servo connector so that the servo will rotate opposite to what it does now? I've seen some threads here and there with mention of openning up the servo and de-soldering and re-soldering internally but this seems a bit extreme. I'd also like to avoid frying a receveir as I've seen hints of this happeneing also....

Thanks a bunch

Ryan

http://www.rcuniverse.com/forum/m_7164146/tm.htm

MinnFlyer

My Feedback: (4)

Nope. It would be FAR easier to switch them in the Transmitter.

rabraaten

I have to ask.....Why?

Dorsal

My Feedback: (17)

In order to reverse a servo internally, you need to switch the wires on the motor inside the servo AND switch the wires on the potentiometer inside the servo. If you just switch the wires on the connector that plugs into the receiver, you will burn up the circuit board inside the servo, because it is NOT polarity protected. You might even fry the receiver.

richg99

You could use a servo reversal cable ....but that is an expensive option.

I found this at helihobby Servo Reverser

*********************************************
All Helis

The Servo Reverser is a quick and easy way to reverse the motion of the servo and it is ideal for flyers who do not have a computerized transmitter.


9.99


PART#DD-SVRV-PKG-01

- Weight: 1 gram
- Size: 8mm x 44mm x 5mm (average)
- Power consumption: 4 mA

Campgems

Or, if you are using a TX made in the last 30 years or so, you could just use the servo reverse switch for the channel you want to switch.

Don

rabraaten

OK...fair enough. The reason for all of this is mainly that I plan on flying the rebuilt plane and the currently flying plane at will. I was hoping to do this with as little trouble as possible, making the transmitter work with both planes with no disassembling. I will pop the battery out and reverse there as necessary...pre-flights will become far more important....hhhmmmm.....which plane was I flying last???? Thanks for all your help
Ryan

Campgems

Ryan, do you have the room to move the servo arms to the other side? instant reverse.

Don

mclina

I'd second what Campgems said. When I started out, I flew my H9 Alpha 40 on the same JR S400 TX as my Four Star. I just built the Four Star so that all of the servo directions were the same as the Alpha, and then I mechanically adjusted the trims to be as close as possible. It still required a bit of re-trimming between planes, but it worked OK.

By my third plane, I finally broke down and got a computer radio with model memory. It is definitely a lot easier.

Good luck

rabraaten

I think I might have enough room to switch sides of the servo arms...the rudder and elevator pushrod tubes are not held at the closest former but the outsides of the servos are pretty close to the outsides of the fuse....worth a try i guess....I do have a computer radio, I bought a 2.4 Futaba 7C last fall in a big sale buying spree but I also bought a flight pack to match the radio I'm using now for the rebuild....I like flying and so far I enjoy simplicity. I'll get into programming soon enough. (The Futaba is for the Sundowner 50 with an OS 55AX later this year.....) I spose for the price (around 40 bucks US) I could just buy another Transmitter and swap the crystal back and forth.... At least I think that is a functional transmitter... http://www.horizonhobby.com/Products...rodID=JSP98140 .

TedMo

Afraid I don't follow your line of thought. If you have a computer radio it must have servo reversing switch, what could be simpler?

Campgems

His plane is a 72mhz and his computer radio, a 7c is 2.4

Ryan, can you switch the rudder and elevator servos linkage and gain some room

As pointed out before, even though you are able to make it work, the trim differences will drive you nuts. That is one reason the old school guys had a receiver and transmitter for each plane. A little tape to make sure the trims were were you wanted and you were good to go.

The Computer radios have a huge number of advantages other than the number of channels, and the mixes, remembering the settings for each plane is probably the top of the list.

Don

kram

My Feedback: (7)

Hard to tell what's going on without looking at the set-up, but it sounds like the guys are correct about switching directions at the transmitter or turning the servo arms around.. Computer radio will do it for each model. Old radio will have to be done manually everytime you switch planes, which could lead to disaster if you forget.

I have encountered a couple of situations where I absolutely had to have a reverse servo for scale looks or convenience or a fit to a particular model and it can be done several ways:

1) get a reverse-wired servo from the manufacturer...they're even listed as stocked on Horizon Hobby for some JR servos
2) get a reverser wire harness... I never trusted that option, although I have no practical experience with failure since I never used one
3) Hitec's digital servos can be swung 180 degrees on their cute little "servo-adjuster" machine, which is about $180, or available for use at some well-stocked hobby stores
4) JR Matchbox. I think Futaba makes a similar device.

Good Luck! This is one of the little logic/geometry problems that makes novice modelers feel smart when they figure it out (or old modelers feel dumb when they realize they set the servo bay up backwards!)

Not that I ever did anything like that. People talk and you hear stories about other guys getting it wrong


mt

Campgems

Kram, is that a P-61 in your photo???

Don

kram

My Feedback: (7)

Don:

Why, yes it is...thanks for asking.

Ziroli P-61 Black Widow, overpowered by two G-62's

Sadly out for repairs since a rough landing last year. Here is a still photo of it and its little sister (VQ model)

www.youtube.com/watch?v=3tqliETnWOI for a short video of me landing it with an engine out. I'd like to brag, but it was mostly luck.

And, yes, it does have a couple of reversed servos: because of cramped compartments, the left aileron and the left outboard flap servos.

mt

Rodney

You could also change brands of servos; for instance Hitec and Futaba turn in opposite directions with the same input.

Campgems

I've got a ASM ARf setting behind me, still in the box. I'm waiting for the retract struts for it before I start building. My first twin. Thanks for the video. Do you use a twinsync?

Don

MinnFlyer

My Feedback: (4)

Since this is totally unrelated to the topic, why don't you guys PM each other?

Campgems

I don't know mike, with 11 servos and twice that many y harnesses, the reverasl issue is bound to come up on this plane

Don't buy that, Ok, back to the P-61 build fourm.

Don

rabraaten

That was great. I love reading something go a bit off topic and then have someone chime in with something silly that makes me smile....

kram-RCU

Rodney:

Of all the solutions I've come up with, I never thought of that one.

It sounds good!

Does it really work?

I freely interchange Hitec and JR servos, of course, which have the same polarity, and I have installed JR receivers in planes full of Futaba servos (shave the tabs off the connectors at the receiver). Perhaps I had to then reverse the channels at the transmitter, but I never noticed. I also installed a couple of Futaba hi-torque aileron servos in a plane otherwise powered by JR, because only the Futabas would fit the wing. But I have never intentionally installed a different brand servo just to get it spinning the other way.

This calls for some "bench research." If it works, then one could get servos spinning opposite directions by matching torque and speed.


mt

MinnFlyer

My Feedback: (4)

For the record, many JR servos are available in "Reversed" mode for about 10 bucks more

Just choose your servo on the Horizon site, then add an "R" to the end of the URL

Example:

Standard:
http://www.horizonhobby.com/Products...ProdID=JRPS821

Reversed:
http://www.horizonhobby.com/Products...rodID=JRPS821R