Official Freewing MiG-29 Fulcrum Twin 80mm Thread

[Evan D]

It prompted a great discussion!

[xviper]

Careful….I intended to state others have PARALLELED batteries on similar systems as the MiG. Hopefully this clears up my statements.

Sorry that I wasn’t more clear.

If you leave the MiG stock….without paralleling the battery connections…and mix different capacity batteries, that would be a disaster.

-GG

That does clear up things a lot. Paralleling the batteries makes this a different scenario. I've always been talking (and thinking) about the Mig as it is stock. I overlooked the fact that dabeven did originally state he was going to "parallel" his 5000 and 4000 mah batteries, giving him a combined "shared" total of 9000mah, rather than the typical 10,000mah, separated - my fault for not re-aligning my thinking. That meant that he would then split that total power source lead back to the separate leads to each ESC, essentially sharing the 9000mah between the two powertrains. It all makes sense now and what he said is applicable. (I gotta slow down when I read stuff. Speed reading has it's bad points.)

[xviper]

Just to be clear (again) my original question was asking *if* the MiG was wired in parallel - in which case I was going to run different sized packs (which is perfectly OK!) *if* it's not parallel (which people are saying it's not) then I'll either run identical packs or solder the wires so they are parallel.

I was *never* suggesting running two different pack sizes in a non-parallel set up. (that would be silly.)

I was *never* asking if two parallel packs could be different sizes, as I already know the answer (yes they can)

...thanks for the replies though!

Dave

And I got sucked into that silliness by not reading your post more carefully. My bad.

[Airguardian]

Two batteries in parallel will have their voltages pinned to each other as the two pos+ will be connected and the two neg- connected. Therefore it is impossible for one to discharge more than the other one. What will happen in practice is that in order to keep this voltage the same the larger pack will supply more current than the smaller pack.

Hi Dave, may I ask what is the point of running the parallel setup you suggest?

I mean, if you are making it parallel, you will be running all the current through a single set of wires instead of two... current will come from both batteries and add up to supply the total amount demanded by the sum of the two EDFs. This means that the section where all the current is flowing through just 2 wires (instead of 4) will need to be able to handle much higher currents, so you will need to size it accordingly and increase the wire gauge so it doesn't lose too much energy overheating. Sure, most twin-EDF setups with a single battery operate that way, but I don't quite see the point of doing this for the MiG-29. I mean, if you were considering using them in series, then totally as that allows to reduce wire gauge while outputting the same power (higher voltage, less current, Joule effect), so you deliver more power with less energy losses and save weight while at it... but... why parallel? what is the gain?

[dabevan]

Hi Dave, may I ask what is the point of running the parallel setup you suggest?

So that I can use different capacity packs (please don't tell me this is not recommended etc - it's fine)

If I make the wires parallel then I'll retain both sets of wires and put a set of jumper wires between the two. These will only need to handle the difference in current between the two packs, not double as you suggest.

[crxmanpat]

Dave,

Did you see my response to you on Facebook where I posted the two sets of connectors you'd need to do what you're trying to accomplish? You need a parallel adapter to hook the batteries together, and then a splitter (one source to two loads) to hook the two ESC/motor plugs to.

Parallel Adapter - https://www.motionrc.com/products/be...39935839436985

Splitter - https://www.motionrc.com/products/be...39935861620921

[Evan D]

Pat that would not be a good way to do it since all the current from both batteries would go through one EC5. Dave's way, to have a simple balance wire between the two stock connectors would be better.

[kallend]

So that I can use different capacity packs (please don't tell me this is not recommended etc - it's fine)

If I make the wires parallel then I'll retain both sets of wires and put a set of jumper wires between the two. These will only need to handle the difference in current between the two packs, not double as you suggest.

correct

[Airguardian]

So that I can use different capacity packs (please don't tell me this is not recommended etc - it's fine)

If I make the wires parallel then I'll retain both sets of wires and put a set of jumper wires between the two. These will only need to handle the difference in current between the two packs, not double as you suggest.

Ok, I guess that makes sense, thanks for ellaborating!

[lusek_pl]

I need help before the model comes, i would like to make a stand under it. Someone can give up put size on the basis of their stands?

[Airguardian]

My two cents: Don't make a stand from scratch, use the foam from the packaging box. You cut openings for the wings and stabs and it doubles up as transport box to the field and plane stand.

[xviper]

I need help before the model comes, i would like to make a stand under it. Someone can give up put size on the basis of their stands?

I used a section of the styrofoam box the plane came in for the stand and that was only for taking to the field so I could lower the gear without hitting the table. For building, I just used a generic stand to do the work. I don't even use a stand anymore at the field. I just put each wing on with the plane at the edge of the table to install the screws from below. I tilt the plane onto its tail to lower the gear.
My work stand for this plane is one of those that the end supports can slide to make the space in between anything I need it to be.

https://robart.com/products/super-stand-ii

[Airguardian]

Forgot to say... My method also makes it more convenient to stack planes atop of each other ;)

[Hugh Wiedman]

I need help before the model comes, i would like to make a stand under it. Someone can give up put size on the basis of their stands?

There's always this stand for $22 at Harbor Freight. It's a great stand to work on the plane from, keeps it up where it's easy to work on. Folds up nice if you want to take it to the field as well. Just a thought.

https://www.harborfreight.com/200-lb-capacity-portable-work-stand-38778.html

[locharrow]

My two cents: Don't make a stand from scratch, use the foam from the packaging box. You cut openings for the wings and stabs and it doubles up as transport box to the field and plane stand.

I use the top of my wine rack in the garage as a stand but don't take it to the field, only take a couple of bottles !
Sometimes take the plane too........

[Captain Moron]

Think I was a bit hard on Motion RC Europe .,When I brought this on the forum both James and Jarrett at MRC Europe have been great and work their socks off to sort tis problem out I now think this could be resolved
Just like to thank Jarrett and James for their response to this problem and also how quick they reacted
Thanks James and Jarrett you have restored my faith in Motion RC👍👍

[James]

Come on Motion RC this is not the way to treat your customer .Order a Mig 29 from Motion RC Europe Fed Ex are unable to do a simple task of deliver this parcel to my address .Contacted Motion RC .Received one email from saying they would look into this .Then nothing then found out they had closed the case .Now I can not get in contact with them .They are impossible to contact. So it looks like I have ended up with no Mig 29 and out of pocket by 585 euros and on top off that just received a bill for VAT and handling charge from Fed Ex for £118 for a model I never received .Thanks Motion RC great Customer Service

Hello Chris,

I found the ticket in the system and there is an internal dialogue between Jarrett and the Warehouse. Looks like it was closed in error. Someone should replay to you today

[Captain Moron]

👌👍👍👍👍

[James]

I completely understand the frustration. It's still early here in the states, but I sent a message to Jarrett already. Give it a few hours.

[4qr1hu9n7]

Come on Motion RC this is not the way to treat your customer .Order a Mig 29 from Motion RC Europe Fed Ex are unable to do a simple task of deliver this parcel to my address .Contacted Motion RC .Received one email from saying they would look into this .Then nothing then found out they had closed the case .Now I can not get in contact with them .They are impossible to contact. So it looks like I have ended up with no Mig 29 and out of pocket by 585 euros and on top off that just received a bill for VAT and handling charge from Fed Ex for £118 for a model I never received .Thanks Motion RC great Customer Service

I ordered a gyro from Motion on October 15. I received no notification as too when it was shipped out. I had to issue a complaint on October 19 to find out what happened. I received notification that same day that it was shipped out. If Motion doesn't care about it's customers ,than there are plenty of other "players" out there that we can go to .