C-17 Globemaster III - 50mm EDF

[PsyBorg]

Amazing job with this. The flight vids are awesome and as stated earlier the post flight interview was great. Maybe FT needs to get him on payroll next just for that. Fly him around to everyone's maidens and have him do an ESPN like post flight show.

You did get very lucky with them wires not catching fire to the whole thing. Not to mention the esc's still function. This will be a crowd pleaser for sure no matter where you fly it.

 

[CMS_1961]

Maiden looked great!!! Great job with this project!!!

Maybe some type NASA ducts and a small DC fan inside will keep things cooler.

 

[Mid7night]

Amazing job with this. The flight vids are awesome and as stated earlier the post flight interview was great. Maybe FT needs to get him on payroll next just for that. Fly him around to everyone's maidens and have him do an ESPN like post flight show.

You did get very lucky with them wires not catching fire to the whole thing. Not to mention the esc's still function. This will be a crowd pleaser for sure no matter where you fly it.

I'll take that job in a hot minute! Yes, I got quite lucky that I didn't fry more than just the wires. I'm hoping that more robust silicone-covered wires will solve that issue so I'm ready to fly for FFW.

 

[ZALATOS]

Nice Job. Nice aircraft

Hi, I printed out the plans and transferred to foam board already I started cut them. Can you please post the order from where and how to start connecting the parts of the fuselage? I really don't know from witch part I start connecting. Show also the top and bottom spines where are going on the body.
Thank you.

 

[liamnave]

wow, that looks really sick. Wherebouts in so cal do you live? I was thinking of starting a club...

 

[DamoRC]

Just amazing! From the history with your Dad, through the build, to the maiden. Such a drama free first flight! Nice to hear you are going to keep it on the ground until FF West - looking forward to seeing it and you in person.

On the ESC wires thing, I'm with willsonman on this, longer power and shorter motor leads would help (I have the same issue with the Diamond). Down side is that the ESC is no longer easily accessible and, in your case, your accessibility issue might be 4 fold! But the heavier duty wires should help you as a first step.

DamoRC

 

[Mid7night]

Hi, I printed out the plans and transferred to foam board already I started cut them. Can you please post the order from where and how to start connecting the parts of the fuselage? I really don't know from witch part I start connecting. Show also the top and bottom spines where are going on the body.
Thank you.

First off; I wish you luck!

As for a part order....had I thought ahead more and numbered them I could provide a better build process, unfortunately that's not the case.

Take a look through all my build-process pictures on the first few pages, that should give you a decent idea of where to begin.

I started with the nose, then did the fuselage.

I'll be honest; the plans could be a lot better in terms of direction, but I only have so much time in my days. And on complicated builds like this one, there is a lot of improvising along the way. My best advice is, just start digging in and follow the progress pics.

 

[Mid7night]

Quick update: I got the new wiring in the wings, and discovered that one of my ESC's had indeed burned out, so I ordered a couple replacements. I just got those soldered up and installed, and all four fans turn again!. Still need to organize the wire mess a little better, but I need a little break; I designed a 1-sheet trainer plane, so I'm throwing that together tonight.

 

[Mid7night]

My 1-sheet trainer was a great success, but it was a bit too windy to get a good feel for it (no video, sorry), so I was happy to get back to the C-17.

Not a lot of work to be done, since I already soldered and tested everything, but the wiring still needed cleaning and organizing. I rerouted the ESC phase wires so they don't lay right on the ESC's themselves, so that should help keep the heat down. I'm still noodling on some ideas to get the ambient temp down inside, but I think even with these mods I'm better off than I was.

 

[Mid7night]

I was just doing a test on a separate project using one of the (supposedly) good ESC's running a different motor, and it was having trouble starting, and even when I got it to run up it ran rough and wouldn't go to full throttle. This now has me a bit worried about the remaining two 'old' ESC's that I left in. I'll do another ground runup later today to confirm their smooth operation, but just in case I also ordered 4 new ESC's as backups. Can't hurt to have a few spares!

 

[F106DeltaDart]

Hopefully everything turns out well! I haven't had the best experience with this Red Brick ESCs, especially with high current edfs. I pretty much run the plushes and Hobbywing ESCs exclusively at this point. Hopefully they work out better for you, and looking forward to seeing it in the air again!

 

[Aviator08]

I was just doing a test on a separate project using one of the (supposedly) good ESC's running a different motor, and it was having trouble starting, and even when I got it to run up it ran rough and wouldn't go to full throttle. This now has me a bit worried about the remaining two 'old' ESC's that I left in. I'll do another ground runup later today to confirm their smooth operation, but just in case I also ordered 4 new ESC's as backups. Can't hurt to have a few spares!

Very cool. FF West will be here before you know it.

 

[Mid7night]

Hopefully everything turns out well! I haven't had the best experience with this Red Brick ESCs, especially with high current edfs. I pretty much run the plushes and Hobbywing ESCs exclusively at this point. Hopefully they work out better for you, and looking forward to seeing it in the air again!

The ESC's themselves worked great, until I melted the insulation on the phase wire extensions and shorted them out!

With the new silicon-coated extensions, better circulation around the wires and actual vent holes in the fuselage I should be in better shape for FFWest.

Although, if I'm honest...I'm still toying with the idea of putting a little bit of dry ice in a perforated container in the nose...

 

[willsonman]

Just to be annoying...

The specific heat of water may outweigh the weight penalty of the higher density of dry ice. Water has a density of 1g/mm^3 and dry ice is 1.4 - 1.6. As Dry ice (CO2) vapor is readily dispersed, the dry ice would have to be in direct contact with the ESCs to really serve any cooling capacity.

 

[Mid7night]

Just to be annoying...

The specific heat of water may outweigh the weight penalty of the higher density of dry ice. Water has a density of 1g/mm^3 and dry ice is 1.4 - 1.6. As Dry ice (CO2) vapor is readily dispersed, the dry ice would have to be in direct contact with the ESCs to really serve any cooling capacity.

Not annoying at all! I like learning new stuff. This is mostly why I haven't been in a hurry to source any and try it. In my head, the sublimating dry ice in the nose of the fuselage would further cool the ambient air as it transits into the hot centerbody, providing more cool air for the fan to blow over the ESC's. But it may be more trouble than it's worth.

 

[Andre]

That or water cooled.

Might need to rework the ESC stack and go with 4 CPU fans directly on the esc's vs 1?

 

[JimCR120]

So Ben, if you have overheating wires, shouldn't larger wires be a reasonable fix? And if the ESC's are overheating a well ventilated heatsink using thermal transfer compound would seem to help.

Surely ventilating the area or distancing them from each other should also be big help (like the idea of a hot coal in proximity to others vs separated).

 

[Mid7night]

So Ben, if you have overheating wires, shouldn't larger wires be a reasonable fix? And if the ESC's are overheating a well ventilated heatsink using thermal transfer compound would seem to help.

Surely ventilating the area or distancing them from each other should also be big help (like the idea of a hot coal in proximity to others vs separated).

Well it's no fun if you're gonna be so REASONABLE and LOGICAL about it all!

Yes, all those options would be improvements, unfortunately the layout as it stands is quite prohibitive - it's too late to move the ESC's to the wings (and extending the power leads is worse than the phase leads), and keeping them on the wing root doesn't open up much real estate.

I theoretically could move them to mount in the fuselage, maybe even mount them with the heat sinks poking out externally through holes in the sides or bottom ... but that would mean making 12 motor connections & 2 Rx connections every flight, not to mention cutting holes in the fuselage which I'm not keen on doing.

Although, now that I've typed all that out....if I COULD find space for them in the bottom of the fuselage, poking out the bottom; cutting holes there would at least mean cutting holes in a lower-stress area of the body, which might be workable.

Gosh darnnit, now you've got me THINKIN'!

 

[JimCR120]

Like you I'm all for preserving the scale look as much as practical. I'm not looking for major reconfigurations but rather workable ways to run less hot.

Even if you don't relocate the ESC's, larger gauge wire should help solve one of the problems. And as for cooling the ESC's, with such a large fuselage, it seems that if you could just get some space between them they wouldn't be adding to their neighboors heat problem with their own. And if there's a discreet way to channel more air through that fuselage via the wheel wells of the landing gear, or the ram air inlets I see outside the mainmount wells, or maybe a couple of mesh screens fore and aft.

Along those lines I have a couple of questions. Are you using retracts? And, what is the dark colored rectangular area on the port side below the pilot's window?

 

[Mid7night]

I did a 70% throttle runup this afternoon in my living room, and all the ESC's and fans seem to respond normally and smoothly. For now, I'm going to leave everything installed as-is. The additional ESC's on their way will be backups as needed. Now....back to family bowling.