Official FlightLine RC 1200mm F8F-1 Bearcat Thread

[Builda]

Loosen the screws holding the retract to the wing and try it, they may be binding when you tighten them. I've got two of these and have never had any retract issues.

Cheers for the quick reply. The intermittent issue is also evident on the test bench with retracts out of the plane. They run fine off my servo tester but as soon as I introduce an Rx they start to misbehave! Ive spent almost as much as the plane on replacement retracts so far and also spent money on a new rx as I thought that might be the issue, but no-that bellyflop option is looking like a good one unless there’s a replacement retract (say an FMS one) that fits in place of the FLRC ones. I’ve only flown the plane once thanks to this issue and I’ve had it 6 months or so. Really stumped as I’ve not seen this problem on both a plane and A test bench before.

[TiredIronGRB]

Cheers for the quick reply. The intermittent issue is also evident on the test bench with retracts out of the plane. They run fine off my servo tester but as soon as I introduce an Rx they start to misbehave! Ive spent almost as much as the plane on replacement retracts so far and also spent money on a new rx as I thought that might be the issue, but no-that bellyflop option is looking like a good one unless there’s a replacement retract (say an FMS one) that fits in place of the FLRC ones. I’ve only flown the plane once thanks to this issue and I’ve had it 6 months or so. Really stumped as I’ve not seen this problem on both a plane and A test bench before.

Very strange, have you tried powering the receiver with a different ESC or BEC it could be a voltage issue.

[Builda]

Very strange, have you tried powering the receiver with a different ESC or BEC it could be a voltage issue.

I’ve tried differrent BEC’s and Rx’s and it’s still got me stumped-I’ve put my servo amp meter on and they are only drawing 0.3A so ?? I have a theory what it might be having thought about it but I’m not 100% sure-I’ll try it out tomorrow as I am over the sight of it today lol

[Grossman56]

When you mount the retracts onto the wing, try installing one screw at a time then cycle them, then two and so on. You'll likely find that when you tighten down one certain screw, they will stop working, don't know why, Warbird Charlie could explain it, I just took him at his word.
Now, if this is the case, you can either back off that particular screw and see if it helps, or shim that position with a small shim and try that. Had the same nightmare with my E Flite Spitty, it worked for me.

Grossman56

[Builda]

When you mount the retracts onto the wing, try installing one screw at a time then cycle them, then two and so on. You'll likely find that when you tighten down one certain screw, they will stop working, don't know why, Warbird Charlie could explain it, I just took him at his word.
Now, if this is the case, you can either back off that particular screw and see if it helps, or shim that position with a small shim and try that. Had the same nightmare with my E Flite Spitty, it worked for me.

Grossman56

They DEFINATELY are not binding up in the wing. What appears to be happening is they randomly draw 2.5a which causes my Receiver to cut the power supply to that channel. They get stuck in both gear up and gear down mode so it’s not a mechanical bind issue. I have verified this by setting one up on the bench out of the wing connected to a receiver. Have tried 3 differrent receivers and 3 differrent BEC’s. The retracts start working again if you unplug the Lipo and plug it back in as it obviously resets the protection circuit in the Rx.

When i run the retracts on my servo tester I have no issues at all, even with them randomly drawing 2.5A-probably cause unlike my Rx’s my servo tester has no protection circuit in, or if it does it’s higher than 2.5amp to trigger it.

Have Emailed FMS with Retract unit dimensions as hopefully they make one that I can drop in that’s more reliable. The problem with the power spiking is that it overdrives the retract and this results in broken microswitches on the PCB inside, leaving the retract useless. I’ve spent almost as much on retracts for this plane as I spent on the plane itself and I’ve only flown it once!!

[TiredIronGRB]

They DEFINATELY are not binding up in the wing. What appears to be happening is they randomly draw 2.5a which causes my Receiver to cut the power supply to that channel. They get stuck in both gear up and gear down mode so it’s not a mechanical bind issue. I have verified this by setting one up on the bench out of the wing connected to a receiver. Have tried 3 differrent receivers and 3 differrent BEC’s. The retracts start working again if you unplug the Lipo and plug it back in as it obviously resets the protection circuit in the Rx.

When i run the retracts on my servo tester I have no issues at all, even with them randomly drawing 2.5A-probably cause unlike my Rx’s my servo tester has no protection circuit in, or if it does it’s higher than 2.5amp to trigger it.

Have Emailed FMS with Retract unit dimensions as hopefully they make one that I can drop in that’s more reliable. The problem with the power spiking is that it overdrives the retract and this results in broken microswitches on the PCB inside, leaving the retract useless. I’ve spent almost as much on retracts for this plane as I spent on the plane itself and I’ve only flown it once!!

I've never had a FL retract go bad...but I've had a crap load of FMS die. I still think there's some other issue, what receivers are you using?

[OV10]

Hello Builda,
Been watching your comments and there are a couple things that stand out as the common factor which is the Rx which you have not mentioned a brand but more so the exclusion of the control box.
Please allow me to walk you through my long distance troubleshooting of your problem so as to help you understand what is possibly happening here based on your comments.
Most run of the mill Rx use a common power buss that can handle significantly more than the 2.5A you mention and are not circuit protected and do not cause a reset to the system voltage.
Initially you say you measured .3A so this perplexes me when you now talk of 2.5A
Retracts are a voltage driven device(nominally 5-6Vdc) using on average 250-500mA. Current(amperage) is not a trigger for operation of the retract.
If your not getting the nominal voltage is when they don't want to work or function properly.
A power spike(voltage) will only drive the motor faster which drives the stop-cam on the worm drive screw faster to the micro-switch which is a mechanical-electro shut off which shouldn't break the switch.
Micro-switches are broken because of mechanical force of that stop-cam downwards on the switch by the trunnion caused usually by above normal/severe landing forces.
The most likely suspect I really think is in between the retracts and the Rx because they are functioning properly on the servo tester and based on the above explained retract operations I gave.
Since you bypassed the Control Box right from the beginning you should check out the Y cable(assuming) that you have the retracts connected to the Rx with.
I would suspect that there is short or crosswire in the Y section causing your voltage problems.
Best regards,

[Builda]

I've never had a FL retract go bad...but I've had a crap load of FMS die. I still think there's some other issue, what receivers are you using?

I’m using Frsky Recievers, and I’ve NEVER had a bad one, let alone 2 or even 3 of them. I sold all my Spek gear a long time ago. As for FMS retracts, they used to be terrible when they had them tiny microswitches in too but all the new generation don’t have them. Also when I run the retract on my tester with an inline Amp meter it’s showing that the retract is randomly spiking at 2.45a from the 0.2-0.3A when it’s not spiking. This spike is definitely tripping the protection circuit in the Rx (which is a good thing) but the reason the retracts are spiking is beyond me. It’s possible that other brands of Rx have a higher cutoff threshold, or none at all (hence no issue, same as wth my servo tester)

[Builda]

Hello Builda,
Been watching your comments and there are a couple things that stand out as the common factor which is the Rx which you have not mentioned a brand but more so the exclusion of the control box.
Please allow me to walk you through my long distance troubleshooting of your problem so as to help you understand what is possibly happening here based on your comments.
Most run of the mill Rx use a common power buss that can handle significantly more than the 2.5A you mention and are not circuit protected and do not cause a reset to the system voltage.
Initially you say you measured .3A so this perplexes me when you now talk of 2.5A
Retracts are a voltage driven device(nominally 5-6Vdc) using on average 250-500mA. Current(amperage) is not a trigger for operation of the retract.
If your not getting the nominal voltage is when they don't want to work or function properly.
A power spike(voltage) will only drive the motor faster which drives the stop-cam on the worm drive screw faster to the micro-switch which is a mechanical-electro shut off which shouldn't break the switch.
Micro-switches are broken because of mechanical force of that stop-cam downwards on the switch by the trunnion caused usually by above normal/severe landing forces.
The most likely suspect I really think is in between the retracts and the Rx because they are functioning properly on the servo tester and based on the above explained retract operations I gave.
Since you bypassed the Control Box right from the beginning you should check out the Y cable(assuming) that you have the retracts connected to the Rx with.
I would suspect that there is short or crosswire in the Y section causing your voltage problems.
Best regards,

These spikes ARE overdriving the retracts, which results in broken microswitches inside the Retract, rendering it useless.

Have tried numerous Y cables, and even gone as far as to strip all the heat shrink off one of them to check none of the wires were shorting out (which they were not) so I re-sealed it.

Also the voltage problem I detected on the tester, NOT the plane. I’ve detected it with the retracts connected directly to the tester (via the inline amp meter) thus eliminating the Y lead altogether. I’m merely assuming the power spike is also happening when the retracts are connected to the Rx and thus upsetting it. Have tried a number of differrent RX’s too (and they are not cheap clones either) and replicated the setup in the plane on the bench (both with the tester and with a receiver). Soon as I use a receiver I get issues with the channel the retract is connected too shutting off as soon as the retract shows a spike, so honestly, short of buy a differrent brand of radio and Rx and try that I’m out of ideas. I might ring Bruce (Xjet on YouTube) and ask him his thoughts on it, but one things for sure-I’ve had 3 sets of retracts in this plane, 4 of the six no longer work due to broken microswitches from overtravelling and the resulting mechanical forces inside the retract. Also I am an engineer of many years, so I’m not a greenhorn as it were, hence my thorough going thru everything. I do find it odd that it’s not just one set of retracts that have displayed this issue, but that could be attributed to the cutoff threshold in the Rx-that I don’t know for sure, hence I might take it down to Bruce.

None of the other servos in the plane have an issue or cause any problem.

[Builda]

These spikes ARE overdriving the retracts, which results in broken microswitches inside the Retract, rendering it useless.

Have tried numerous Y cables, and even gone as far as to strip all the heat shrink off one of them to check none of the wires were shorting out (which they were not) so I re-sealed it.

Also the voltage problem I detected on the tester, NOT the plane. I’ve detected it with the retracts connected directly to the tester (via the inline amp meter) thus eliminating the Y lead altogether. I’m merely assuming the power spike is also happening when the retracts are connected to the Rx and thus upsetting it. Have tried a number of differrent RX’s too (and they are not cheap clones either) and replicated the setup in the plane on the bench (both with the tester and with a receiver). Soon as I use a receiver I get issues with the channel the retract is connected too shutting off as soon as the retract shows a spike, so honestly, short of buy a differrent brand of radio and Rx and try that I’m out of ideas. I might ring Bruce (Xjet on YouTube) and ask him his thoughts on it, but one things for sure-I’ve had 3 sets of retracts in this plane, 4 of the six no longer work due to broken microswitches from overtravelling and the resulting mechanical forces inside the retract. Also I am an engineer of many years, so I’m not a greenhorn as it were, hence my thorough going thru everything. I do find it odd that it’s not just one set of retracts that have displayed this issue, but that could be attributed to the cutoff threshold in the Rx-that I don’t know for sure, hence I might take it down to Bruce.

None of the other servos in the plane have an issue or cause any problem.

Forgive me, it was an AMPERAGE problem not voltage. The amps are spiking. The voltage is fine as far as I’m aware.

[Builda]

Have dug out that little distribution board thing which I did away with and used Y leads instead as I notice looking at the schematics that the Rx gets its power from that board too-it’s a long shot but I’m wondering if it will isolate the Rx from any power or amperage fluctuations and as such eliminate the problem. Seems odd though that I have to do it this way. Has anyone else done away with that distribution block and put Y leads in????

[Builda]

Hello Builda,
Been watching your comments and there are a couple things that stand out as the common factor which is the Rx which you have not mentioned a brand but more so the exclusion of the control box.
Please allow me to walk you through my long distance troubleshooting of your problem so as to help you understand what is possibly happening here based on your comments.
Most run of the mill Rx use a common power buss that can handle significantly more than the 2.5A you mention and are not circuit protected and do not cause a reset to the system voltage.
Initially you say you measured .3A so this perplexes me when you now talk of 2.5A
Retracts are a voltage driven device(nominally 5-6Vdc) using on average 250-500mA. Current(amperage) is not a trigger for operation of the retract.
If your not getting the nominal voltage is when they don't want to work or function properly.
A power spike(voltage) will only drive the motor faster which drives the stop-cam on the worm drive screw faster to the micro-switch which is a mechanical-electro shut off which shouldn't break the switch.
Micro-switches are broken because of mechanical force of that stop-cam downwards on the switch by the trunnion caused usually by above normal/severe landing forces.
The most likely suspect I really think is in between the retracts and the Rx because they are functioning properly on the servo tester and based on the above explained retract operations I gave.
Since you bypassed the Control Box right from the beginning you should check out the Y cable(assuming) that you have the retracts connected to the Rx with.
I would suspect that there is short or crosswire in the Y section causing your voltage problems.
Best regards,

Ok, so further to all this I was lying in bed thinking it over and not knowing got the better of me, SO I have again bench tested the setup out of the plane but this time using the little blue distribution box. I can connect a servo to the gear slot on the blue box and it will work perfectly with me operating the switch for the landing gear. Next I plug a Retract in-the first movement of the retract is the last until I unplug it, and re-connect it to the blue box-then it will operate in the opposite direction, stop, and again not work again. I can again unplug the Retract from the blue box and plug it back in and again, I get travel in one direction then nothing. If I then plug a servo into that port on the blue box it functions perfectly just as it did before, so if I have this right I have isolated the Rx from the effects of any kind of amperage spikes from the retract, and also proven that the problem is with the retract and not the signal or power supply to it. I then connected the retracts (I tried all this with both of them, one at a time) to my servo tester and as usual, they cycle back and forth without issue. So I’m first to admit defeat on this issue, I’ve tried everything I can think of and no joy-so I’m not going to waste my money on yet another set of retracts that will likely do the same-instead I’m gonna buy the power upgrade, glue up the flaps to the wing, and make it a belly lander. You get to a point where you have to financially draw the line (and psychologically for sanity) and this plane has certainly got to that point. Out of interest I will connect a Dynam and an fms Retract to this setup tomorrow and see if they suffer the same issue.

[radfordc]

One solution is to get rid of the microswitches and the internal retract control board. Here is how I did it: https://www.rcgroups.com/forums/show...postcount=1044

[Builda]

One solution is to get rid of the microswitches and the internal retract control board. Here is how I did it: https://www.rcgroups.com/forums/show...postcount=1044

I love that idea, I have one of those controllers here too-I’m sure I will be able to get at least one working pair out of all the broken ones here! Tell me, does that controller operate them slower also?

[radfordc]

I love that idea, I have one of those controllers here too-I’m sure I will be able to get at least one working pair out of all the broken ones here! Tell me, does that controller operate them slower also?

That one doesn't, but I think that there are some that do.

[OV10]

I love that idea, I have one of those controllers here too-I’m sure I will be able to get at least one working pair out of all the broken ones here! Tell me, does that controller operate them slower also?

The controller(both internal or external) does not control the operational speed of a retract.
Speed is controlled by TPI of the worm drive screw and motor rpm.

There has been a long established thread( started 5 years ago) about retract controller upgrades under the RCG label of FMS 1700mm retract mod (stock and all metal upgrade)
I was a contributor to it 2 years ago.
Radfordc's June 2017 posting uses the exact same principle.:Cool:

[Builda]

Have FINALLY found the problem.....Was the BEC all along......it wasn’t big enough! I guess we all have blonde moments, that was mine lol. I found it when I hooked up my 2 brand new (just arrived today) retracts and they only went in one direction as usual, yet with just one connected it worked fine-so I tried a 5a BEC instead and that fixed it. I’m tempted now to get a 10a one for that plane, although in theory I suppose it shouldn’t need it. At least I solved it. As for all the retracts here with broken microswitches, I’m gonna re wire them to be used with that seperate controller I have. Thanks to everyone who contributed 10c toward me solving this issue-and if you ever need to buy just the retract unit on its own (without the landing leg) I got them dirt cheap from Hobby-paradise.com. Part number E814. Everywhere else only sold them as a complete unit (complete with legs). Guess I have a few spares now lol.

[Mad Baron]

Had a bit of bad luck today. My Bearcat is no more it got too far from me and couldn't tell exactly which way it was going and it fell out the sky. When I made my way to the wreckage one aileron was separated from the wing and I don't know if it came loose in flight or the impact crash. :(

[rifleman_btx]

Awe man that suck, sorry man :(

[Mad Baron]

I'm upset that it crashed but that's the way it goes. These planes are on borrowed time as soon as the box is opened. I do have another Bearcat kit to put together I bought about a year ago so I will have another cat to fly again.