jetnuno

Hello

This weekend I logged some more flights in my F18F, but something stange happened...

I am now flying in 2,4Ghz (FASST) with a Power box Evolution and a Tam gear fail safe. All the valves and sequencer are jetronics.

All is operating flawless but.... when I pressure the power box switch to turn it on, sometimes( not all times) the gear comes up and got some homework repairing gear doors, etc

Anyone knows why is this happening?

Regards

Nuno

JP-1

Has the fault just occured out of the blue? or new aircraft, new set up, could it be fail safe related, particularly if on 2.4 Ghz

Dave Wilshere

Nuno

When did you last set the FS/bind process, sounds like something has changed in the set up since the last update. Try rebinding

Dw

jetnuno

Hi

Lets clear this out a bit...

I have changed to FASST in June. Since then I have logged arround 20 flights. All in all the plane as 96 flights, but I don't think it is a bind issue.

At first I thought it was related with the Tam Jet fail safe, so I tried to power on the power box with several pressures in the tank to see if it was a tamjets failsafe/pressure issue. No changes here

Then a frien told me that I have to keep my figer pressing the power on button for over a second or if less time the gear might come up[&:]

Sounds funny, but I have to try it. Nevertheless, I was expecting that you guys might chime in with some guessses

Regards

Nuno

SpiderJets

All electronic valves have a default setting ; this means, they "move" to one "direction" when they do not get a servo signal (yet).
I guess in your case, it seems like the valve for the retract is acting your retracts for a fraction of a moment in the wrong direction (during binding/booting when you switch the rx on).
Reverse your retract valve channel and swap the two air lines going to the retract.
That could solve it.

Nicolas.

tassos p

Hi Nuno,

Are you using 6014Rx?

The jettronics sequencer has an issue with 6014. You need to use a signal booster for it to operate fine or use a channel of the powerbox.

I'm using the 6014 Rx and have installed a signal booster with the sequencer and I have no issues whatsoever.

Also the sequencer has memory. It keeps in memory the last off condition. So if you switched off with gear up and switch back on again it will go to gear up no matter what your gear switch on your transmitter is.

Tassos

Dave Wilshere

Tassos

Two good ones, but later sequencers should not need this. Option 2 is a possible!

Dave

Rob Howarth

Nuno,

It most probably is dependant upon which 6014 RX you are using. If you are using a 6014FS the signal output voltage is only 2.7v and cannot be detected by the Jet-tronics valve on initiation. However, the 6014HS does have a 5v signal output. I learnt this from the exact same experience.

Rob

jetnuno

Hi

Thanks. My sequencer is the latest one (2 years), at least it as the yellow screw. The old one as a red one. I have a 6014 HS and the gear channel is not going in the PB
Option 2 is not valid, because it happened after refuel, so the gear and the gear switch were down when power was turned on.

Nicolas - your idea makes sense. I'll give a it a try. What about what my friend told me about pressing the button for over a second? Does it makes sense?

Regards

Nuno

topgun24

My Feedback: (25)

I have found this happens when you have an analog servo for the gear retract causing it to pulse at power up causing the gear the to pop up and then go back down. I changed the analog servo to digital and it has NEVER happened again in over a year. Prior to changing the servo it would happen every now and again. We used to lift the model every time we turned it on. No more!!

KC36330

With the Tam Jet failsafe unit you need to set your failsafe in the radio (binding with JR, not sure about how to do Futaba) with the gear switch UP. the failsafe then prevents the gear from cycling and will put it in the DOWN position if not already there till it sees a solid gear down signal. binding it with the gear in the down position can/will cause the gear to cycle on power up sometimes.

jetnuno

Hi KC3630

If I remember correct I Bind it with gear UP as per instruction manual. I'll bind it again any way...some good inputs here

The jetronics valves use analog signals, so nothing to do about it...

Regards

Nuno

rhklenke

My Feedback: (24)

You didn't say what RX and TX you are using, but I'm assuming that you are using a combination (higher than 7 channels) that has failsafe on more channels than just the throttle, correct? If that is the case, then, as others suggested, there might be an issue with where the failsafe on the gear channel is set. It should be noted though that in the Futaba systems (FASST included), the failsafe settings are *not* stored in the receiver (except for the 7-channel and lower RX's where only throttle has a failsafe setting) and it usually takes several seconds or more after power on before the failsafe settings are downloaded from the TX to the RX. In addition, in the FASST system, if you do not have the TX on before turning the RX on, the RX will power up the servos, but not send out any pulses to them until the TX is turned on. Perhaps the Tams Failsafe device behaves differently in that case and pulls the gear up?

Bob

AndyAndrews

How do it know?

rhklenke

My Feedback: (24)

Andy,

How do it know what? Most of what I said comes from playing around with two 6014 RX's on a 10CAP this past weekend on a Powerbox RSS setup for a UAV we are working on. I setup the failsafe on the throttle channel and on channel 8 which is used as an input to the RSS to allow it to determine if one of the RX's has gone into failsafe. During that experimentation, I discovered that with FASST 1) nothing comes out of the RX when you first turn it on if the TX isn't on (I knew that already, but confirmed that) 2) the failsafe is not present in the RX when it first turns on, and 3) the failsafe settings take a few seconds or so to get downloaded from the TX to the RX.

2 and 3 I determined by (multiple times) turning on the TX, and then the RX, and then turning off the TX. If you turn off the TX right after the RX comes on and starts driving the servos, it will not go to the failsafe settings - all channels hold. If you leave the TX on after the RX comes on and wait a bit, they you *will* get failsafes on the channels where it is specified. The time you have to wait is somewhat variable and I couldn't pin down a real minimum or maximum, but to be safe, you have to wait at least 15 seconds or so. I recall reading somewhere that in the Futaba PCM system, the TX tacks on a "failsafe packet" with the failsafe settings every so often to the RX - thus the waiting time, you have to wait for the TX to decide to send one of those packets to the RX. My testing indicates that FASST works the same way - i.e., the failsafes don't go from the TX to the RX on every packet, just every so often...

Bob

Eddie P

My Feedback: (4)

My bet is the analog servo on the gear switch. I had the same issue as well.

rhklenke

My Feedback: (24)

The original post states:

"All the valves and sequencer are jetronics"

I'm assuming that means that he does not have any servos in the gear system at all.

Bob

AndyAndrews

lol, sorry, the "how do it know" deal is an old joke... I was applying the joke to the title of the thread.