justy_123

Hey guys.

Been flying my Hangar 9 Spitfire 60 MII for a couple of years now and love it. Never had a problem with it. However, today I went out to the field and flew it. First flight went great but the second was not so. I was lucky! [:-]

I took off and I new something was wrong when the landing gear would not go up. As I turned on downwind to land I suddenly lost all control of my model for about 4 secs. Scared the hell out of me. Managed to gain signal on and off on base leg and somehow landed it! The only thing that saved the model diving into the ground was the fact that I had the fail safe set correctly. So that when the signal was lost all controls automatically went to neutral and throttle to idle. After this I packed up and went home. [X(]

In my 6 or so years of RC flying I have never experienced any signal loss. So what went went wrong?

Well, I think it has something to do with my landing gear setup using a separate battery to power the retract servo. The last couple of times that I have flown the spit, this setup has been real dicky. I have 2 switches ( 1 for each battery pack) and I have been noticing that when I flick the switches on, sometimes the gear won't work. But the flight controls will. So I have been switching the switches off then on again and in a different sequence. The gear and flight controls then work like normal. I check this problem before each flight and I make sure everything works. Been doing this for a couple of months with no problem. Until now!

After some troubleshooting on the work bench, I have noticed something. When I switch both the flight battery and retract switches to the on position and the gear will not operate (as stated in the above paragraph) the radio fails a range check! I only get 5 meters away from the model and I lose all signal!

This has got me stumped? This switch thing where the retracts wont work does not happen every time. Do you guys have any thoughts on this weird problem? Could it be the switches?

I ain't gonna fly the model until I get this issue sorted out!
I have used all my luck!

Many thanks
Justin

JohnBuckner

My Feedback: (1)

Justin in my opinion sometime in our attempts to acheve redundancy by adding complexity has a negative effect on reliability. I also beleve the mechanical switch is one of the most unreliable components in the link between our thumbs and the servo.

First thing with fully charged batterys by pass the switchs and see if you can repeat the problem. If not try a new switch on the radio and flight servos forget the gear. If you have no problem then replace the gear switch or my preferance fix the servo's lead and go back to a single battery/switch setup.

John

jetmech05

Switches are easy to swap out...your gear switch is intermittent, for that reason alone I'd change the gear switch. You have duplicated the problem before, replace the switch and try at least 5 times to duplicate the problem before doing another range check and with fully charged batteries and the motor running
Good Luck

sugarfox

My Feedback: (1)

I'd be willing to bet my last buck that its the switch. The switch is the weakest part of our systems in my opinion. We shock mount everything but the switch. I quit using the standard switches that are with the radio systems and have been using the MPI or JR heavy duty switches and have had no problems. I also "cycle" them on and off several times to prevent corosion (sp). good luck sugarfox.

dignlivn

I would get rid of the Gear Switch also. What size
Rx pac are you using ? Maybe a larger capacity pac
would be in order. I too use only HD Switches.


Bob

jaka

Hi!
You say you have a separate battery for the retracts...connected how??

Rodney

You should be the safest by using a separate battery and switch for the gear just as you have been doing. I'd guess that the most probable problem is somewhere in the harness, switch or battery being used on the gear. Very possibly some arcing somewhere that is creating RF interference. This could be worn brushes on the gear servo, switch contacts on the switch to the gear powering battery or even a broken wire making intermittent contact. Going back to a single battery is just asking for more problems, your original way is the best.

All Day Dan

My Feedback: (5)

Justin, Post a diagram of the battery, receiver, servo and switch circuit. Using two batteries is never a good idea. You may need isolation diodes. Dan.

justy_123

Thanks guys heaps for your posts. Some good info!

Both batteries are stock JR rx batteries 1100mah. I don't think I need to go bigger. The switches are stock standard aswell.

What I think ill do is bybass each system in the setup and try and limit it down to the problem. Will start off with the switches. Hopefully they are the problem. If not I am gonna replace them with JR HD ones anyways like many of you have said. Cheap insurance for sure. I have thought many times about what happens if the switches fail!

The 2 battery setup has been working well. I got the wireing diagrm off RCU. Can't really remember exactly the details of the setup but its the one where u cut the + wire going into the gear channel on the receiver and using a Y-harness. It may even be that cut + wire moving around in the fuse. Will heat shrink that maybe.

Will try this tonight. Will let you guys know how I go. [8D]
Thanks again guys.

Justin

All Day Dan

My Feedback: (5)

Solving a problem like this on the benchtop is hard enouh but you are half way around the world. Here's another thought. If you are switching your retract battery on to your retract servo and the problem shows up you may have a bad set of electronics in your servo that would not show up until the servo is powered. A bad signal circuit in the servo would load them all down. Maybe that's why you went into fail safe. I don't kow how well those signal lines are isolated from one servo to another. Dan.

justy_123

Well guys I have nailed it down to the gear switch!
After about 15mins of switching the switches on and off and almost 50 retractions, [8D] I got the retracts to not work 2 or 3 times!
When this happened, with both switches on, I touched the retract battery switch and down came the retracts! So this has to be the problem! So off I go to the LHS tomorrow to buy some brand new JR HD switches! Will fit them, do a comprehensive range check and go flying! [X(] Hopefully all goes well!

The link below is the choice of switches I have to choose from.
Which one do you guys like?

http://www.modelflight.com.au/jr_switches.htm

But how would would this switch this cause the radio glitches?

Thanks for your help guys!

jetmech05

there could be some arcing in the switch...this will happen with a micro build up of carbon...I'll bet the 2 switches, gear and airplane are next to each other, componding the problem...at least you got the problem found

justy_123

Yep! Both switches are right next to each other! In fact they couldn't get any closer!
I cant believe a dodgy switch almost brought down my model!
Thanks guys for your help!