Official Freewing T-33 Shooting Star 80mm EDF Thread

[radfordc]

I keep finding new ways to crash. Last week I flew my T-33 again for the 6-8th time. All flight before were normal. This one the jet went wildly out of control. Turns out the gyro was acting in reverse. I had changed nothing between this flight and all the others. Gyro seems to have reverted to it's default settings on it's own.

In the video you can see the gyro moving the rudder and ailerons in reverse...

https://youtu.be/Xt8pDmrn2MA

[timmybeetle]

[QUOTE=radfordc;n316370]I keep finding new ways to crash. Last week I flew my T-33 again for the 6-8th time. All flight before were normal. This one the jet went wildly out of control. Turns out the gyro was acting in reverse. I had changed nothing between this flight and all the others. Gyro seems to have reverted to it's default settings on it's own.

In the video you can see the gyro moving the rudder and ailerons in reverse...

Hi

very strange, this gyro can not change his settings without getting into program mode?

Setting Methods
Setting Menu
Press and hold down the button for more than 2 seconds (long press)

Gyro Directions
It’s extremely important to verify that the gyros of all
channels are reacting in the correct direction before flight,
otherwise it could lead to losing control or even crash
during a flight!

Remote Master Gain
The GAIN is used to control the master gain remotely. You can make a linear adjustment by using a knob or slider on
your transmitter, or make a 3-level gain control using a 3-way switch. The master gain is just an optional channel that
the gyro can still work properly without connecting this channel.



Maybe if you have yours remote gain on a nob ore switch maybe the issue, otherwise it's not explainable!
It seems gyro is reacting on its maximum gains....

Grts Hans

[xviper]

Putting an A3L on a master gain knob or a switch will not reverse the gyro control direction. If there's too much gain, all it will do is oscillate like crazy, not reverse itself. Also, a knob or switch that is set to maximum gain won't actually give "maximum" gain. It will, at worst, give 100% of whatever the gain pots are set at. In the case of the A3L, even if the gain pots were left at just under 50%, that would mean 100% of 50%, so still only 50% and at the speed that the jet was going when it went nuts, 50% gain would not have caused an oscillation.
Unintended reversal of an A3L could happen if there was an odd power up and/or if the menu button was pressed by an obstruction. It is also very possible that reversal never happened and that the A3L came loose from it's mount. Sticky pads can lose their stick if the environment is dusty and even if a mounting platform was made (like a piece of wood), the wood can come detach or loose. Even a slightly loose gyro can cause the plane to do very crazy things.
Finally, did you have the control surfaces run through the control box? These things have been known to have intermittent common ground circuit shorts. Both my T-33s went inverted right after take-off. After repair, I took the control box out of the equation and it never happened again. I sold the first one and I still fly the second one.

[radfordc]

The gyro was not configured with a remote gain, but it was configured with a switch to change modes. The switch was set so that the gyro was either off or in rate mode...heading hold was disabled. The gain was set to 25% on the gyro. The gyro was securely mounted to a plywood floor...the floor and gyro were still firmly attached after the crash. I have since ripped the plywood floor out of the plane but the gyro is still mounted to the wood. When I initially installed the gyro I did the programming for all three axis's to get the correct movement of the surfaces. I flew the plane at least 6 flights with the gyro in rate mode with no issues.

Now, all three surfaces are reversed which makes me believe that the gyro has reset to it's default settings. To reset the gyro to default requires a very specific procedure..."Press and hold the button while power on the gyro, you will see both Blue and Red LED turn on. Keep holding the button for more than 4 seconds and don’t release it until you see the LED flashes Blue & Red twice, which indicates that all the settings have been restored to the factory default." I don't think that it's possible to accidently do this, so does that mean the gyro did it on it's own "magically"?

Yes, the controls were working through the blue box, but I can't see how the blue box could change the direction of the gyro corrections. Maybe one surface, but all three?

[xviper]

so does that mean the gyro did it on it's own "magically"?

Yes, the controls were working through the blue box, but I can't see how the blue box could change the direction of the gyro corrections. Maybe one surface, but all three?

It's a mystery "glitch". I would be hesitant to use that gyro again. I'm using a lot of these A3L's in many planes and only once did one ever act up and that was after a pretty nasty crash. I think the internals of the gyro got damaged.
I've never trusted those "blue boxes". I try to hook up at least the AIL and ELE directly to the RX. But you're probably right - maybe one but not all surfaces. For me, it was always the ELE when something went wrong.

[F22trainer]

I had to wait awhile, but I had to have one. While most of my efforts are still rooted into the balsa forest, I have started dabbling with the edf’s. Nice product James.
See ya round’

[radfordc]

After my crash with the gyro problem I asked MRC if they would cover any of my loss. They were not interested in doing that. They recommended that I do better preflight inspections. Good advice for sure.

[timmybeetle]

After my crash with the gyro problem I asked MRC if they would cover any of my loss. They were not interested in doing that. They recommended that I do better preflight inspections. Good advice for sure.

Hi

Well in this case I must say they are right.
I also had one time a short preflight inspection, I could say there where some reasons I was distracted but in the end I as a pilot are responsible for doing it right.
I reversed my ailerons, using a set of my second P40 from BH because first one where damaged due to another crash sadly.

So now before every flight I stand behind my plane and check all moving surfaces , and if someone is talking to me I get unfriendly and say he should leave me alone doing my preflight checks.

Greetings from Hans

[MikeT]

After my crash with the gyro problem I asked MRC if they would cover any of my loss. They were not interested in doing that. They recommended that I do better preflight inspections. Good advice for sure.

I feel your pain but can't understand why you thought Motion should pony up on this.

Mike

[radfordc]

I feel your pain but can't understand why you thought Motion should pony up on this.

Mike

Yeah, you're right. I guess it's just frustration with buying products that are supposed to work "by the book" and then they don't. MRC products have cost me a lot of money it the last few months. First the Mig-29 flap issue and now this gyro problem.

[radfordc]

Well in this case I must say they are right.
So now before every flight I stand behind my plane and check all moving surfaces ,

I do that too. But, I didn't pick up the plane and check to see that the gyro was moving the controls in the correct direction.

What I should have done was keep the gyro turned off until the plane was at high altitude and then turn it on. Lesson learned....just because it was working correctly on the last flight doesn't mean it's still working correctly on the next flight.

[MikeT]

Yeah, you're right. I guess it's just frustration with buying products that are supposed to work "by the book" and then they don't. MRC products have cost me a lot of money it the last few months. First the Mig-29 flap issue and now this gyro problem.

I hear ya. This hobby can be frustrating at times.

Mike

[quitcherbitchen]

What I should have done was keep the gyro turned off until the plane was at high altitude and then turn it on. Lesson learned....just because it was working correctly on the last flight doesn't mean it's still working correctly on the next flight.

We get complacent and the preflight check is one of those "habits" that you need to develop. I have done all the same things including not checking the fail safe. That one caused a fly away. Make sure your throttle is set to zero for failsafe. Otherwise, with the gyro on the plane will fly itself till out out of battery-perfectly.

[radfordc]

After I posted about my crash in RC Groups someone else posted this:

"Wow, just happened across this since this jet is on my wish list. I flew the hobby eagle A3 in a plane a few years ago for about 6 months with no issues and then one day, on my 3rd flight of the day, the plane lost control and went in. Forensic testing revealed the A3 had reset to default settings, which unreversed the ailerons. Afterwards, I was able to reprogram it but no way will I put it in another plane."

[davegee]

Does anyone have an idea or technique they use to prevent scuffing or damage to the bottoms of the tip tanks without pulling the paint off, like tape often does?

Thanks for any ideas.

Cheers

davegee

[Evan D]

I use Associated RC car chassis protector. It's thick teflon like plastic with a sticky back. Usually I wait until I scrape a tip, fix it and then put a strip of the plastic over it and at the same spot on the other side.

[davegee]

I use Associated RC car chassis protector. It's thick teflon like plastic with a sticky back. Usually I wait until I scrape a tip, fix it and then put a strip of the plastic over it and at the same spot on the other side.

Thanks, Evan. I'd like to take a look at that. Do you have a link for it, or should I just google "Associated RC car chassis protector", or something like that?

Thanks,!

Davegee

[Evan D]

I did a quick search and this came up. I'm sure other places have it too..

Team Associated Chassis Protective Sheet [ASC9787] | Cars & Trucks - AMain Hobbies

[davegee]

I did a quick search and this came up. I'm sure other places have it too..

Team Associated Chassis Protective Sheet [ASC9787] | Cars & Trucks - AMain Hobbies

Thanks, Evan. Something like that is on the right track, for sure. Appreciate the link.

Cheers

davegee

[Evan D]

You’re very welcome. I use it a lot. On my high buck fiberglass gliders in case there’s a rock in the grass, wing tips, corners on ailerons, over tail skids…

Another option is piano wire tip skids. On planes like my F-16 I have sidewinders on the tips so the skid tape won’t work so I made piano wire skids. I’ll see if I have a picture saved… Sorry you'll need to zoom in on the tip to see it...