Official Freewing MiG-29 Fulcrum Twin 80mm Thread

[steven gubala]

Looking good AirGuardian

[Airguardian]

Thanks Steven!
I just glassed the stabs too,, using 18g/m² glass cloth and WBPU.
She should be quite tough after the upgrade :)

[kallend]

It is the intention of this config in the first place. A loop is NOT bad in this case.

If it is the intention, how come CC does not state to do it that way?

If ground loops are OK, why does a Spektrum system designer (Andy Kunz) specifically advise against creating them?

At least you and Evan are now acknowledging that there IS a ground loop if connected that way, which is, I suppose, a positive development.

[leithalweapon]

If it is the intention, how come CC does not state to do it that way?

If ground loops are OK, why does a Spektrum system designer (Andy Kunz) specifically advise against creating them?

At least you and Evan are now acknowledging that there IS a ground loop if connected that way, which is, I suppose, a positive development.

Maybe ask Andy Kunz?

[janmb]

If it is the intention, how come CC does not state to do it that way?

Been a while so don't quote me on the exact wording, but the quick sheet or manual states something along the lines that the two outputs (which to be clear are not independent) are intended for connecting at various locations in your rx system to better distribute load.

The two leads coming out of that box are already on a common ground, as are the positives.

If loops concern you greatly, there's always the option of running signal only from rx to bb, which in this case would be fine too.

[Evan D]

John, when I acknowledged there is a ground loop I also said there is an extremely small differential in the potential. There are always tiny losses due to wire resistance but the micro/ milli volt difference would not cause any problem at all. The normal concern with ground loops is the possibility of a high difference in potential in the grounds which will cause issues. Not the case with the CC dual output BEC.

[mshagg]

Evans workflow is consistent with how I'm using the twin outputs from the CC BEC and freewing planes with an mcbe/junction box (or even planes with a seperate Rx and hobbyeagle gyro). Which is pretty much all of them nowadays.

Acknowledge the presence of a ground loop, but I think there's an advantage to getting the voltage source closer to where it's needed.

Probably dependent on how you have it wired as well. If it's stock setup with 6 cables going from the Rx to the mcbe then you have ample redundancy/current capacity with parallel connections to the power rail. Any of these planes which I transport assembled have only one connection between the rx/mcbe (gear channel) with servos running direct to the Rx. Including the jet in question here.

If ground loops are OK, why does a Spektrum system designer (Andy Kunz) specifically advise against creating them?

Andy and his team probably have KPIs regarding complaints, returns and refunds arising from the operation of the equipment he designs lol. Andy says we should only be using genuine spektrum radios, too

[Airguardian]

MiG-29 maiden done! :DDD

[Hugh Wiedman]

MiG-29 maiden done! :DDD

Beautiful flying, especially for a maiden. Looks like you've been flying this forever, outstanding landings as well.

[Airguardian]

Thanks Hugh!
Well, there are definite similarities with the Su-35, and I have been flying that one for quite a while, so there's that. :)

[kallend]

Been a while so don't quote me on the exact wording, but the quick sheet or manual states something along the lines that the two outputs (which to be clear are not independent) are intended for connecting at various locations in your rx system to better distribute load.

That is correct, but it can (and should) be done without creating two separate paths from receiver to BEC to create a loop. CC certainly didn't recommend doing it that way.

First you and Evan denied there was a loop. Now it has been demonstrated that there certainly is one you move the goalposts and admit there is a loop, but it's OK.

[janmb]

That is correct, but it can (and should) be done without creating two separate paths from receiver to BEC to create a loop. CC certainly didn't recommend doing it that way.

First you and Evan denied there was a loop. Now it has been demonstrated that there certainly is one you move the goalposts and admit there is a loop, but it's OK.

There obviously is a loop if you choose to make one, but since absolutely all of it is on the same potential, that is completely unproblematic

[Flyingpit]

anyone know when the MIG-29 will be available again? e.g. at MotionRC?

klaus

[kallend]

There obviously is a loop if you choose to make one, but since absolutely all of it is on the same potential, that is completely unproblematic

Whoosh. Forgot about Maxwell's equations, did you?

Ground loops are BAD. Electrical Engineering 101.

At least you are no longer in denial that there is a ground loop.

[Evan D]

No, differences in potential in a ground loop is bad. In our case there are sufficient connections between the possible loops to minimize the differences.

Just about any circuit has ground loops within the circuit due to resistance in those circuits, they are not important unless there is significant resistances or no community between the grounds and a difference in potential is present.

[xviper]

anyone know when the MIG-29 will be available again? e.g. at MotionRC?

klaus

RC Castle still has stock but I have a feeling that once those are gone, there may be a period of time of "out of stock" till Motion and Freewing has figured out how to remedy the weaknesses in this plane. And really, who knows how long that will be and I'm sure Motion ain't talking.

https://www.rc-castle.com/index.php?route=product/product&product_id=8845

In the meantime, I'll keep flying mine and doing my best to avoid flight scenarios that "might" succumb to those weaknesses. So far, so good.

[kallend]

No, differences in potential in a ground loop is bad. In our case there are sufficient connections between the possible loops to minimize the differences.

Just about any circuit has ground loops within the circuit due to resistance in those circuits, they are not important unless there is significant resistances or no community between the grounds and a difference in potential is present.

Wrong.

https://hackaday.com/2017/03/09/wtf-are-ground-loops/

[Evan D]

If you go by that there are no ground loops using the BEC outputs to the MCBe and receiver since they have connected grounds. Case closed. But I stand by my reasoning that there are slight ground loops due to resistance in the circuitry.

[Evan D]

I don't think so. I think the reason it's out of stock is simply due to shipping issues. I think FW will simply be putting in the slightly upgraded servos as the assemble the newer kits,

RC Castle still has stock but I have a feeling that once those are gone, there may be a period of time of "out of stock" till Motion and Freewing has figured out how to remedy the weaknesses in this plane. And really, who knows how long that will be and I'm sure Motion ain't talking.

https://www.rc-castle.com/index.php?route=product/product&product_id=8845

In the meantime, I'll keep flying mine and doing my best to avoid flight scenarios that "might" succumb to those weaknesses. So far, so good.

[janmb]

No, differences in potential in a ground loop is bad. In our case there are sufficient connections between the possible loops to minimize the differences.

Just about any circuit has ground loops within the circuit due to resistance in those circuits, they are not important unless there is significant resistances or no community between the grounds and a difference in potential is present.

This.