1/10th Scale Westcraft B-17G Electric Conversion

[rifleman_btx]

If I recall the top turret was manned by the navigator or something like that..

[Ole-Timer]

Top Turret gunners were the flight engineers of the crew. As long as there were no enemy aircraft around, if there was a system issue onboard, he was fixing it or attempting to. It was also commonplace for crew members to learn others responsibilities in case of death or injury in flight to fill in where needed. The top turret was always manned anytime the bird was vulnerable.

[fhhuber]

Several minor variants... Some, the radio operator was the navigator and there was a bubble window just forward of the top turret for taking the sextant sightings.

Obviously the radio operator had a lot of sit and listen and little time they actually transmitted because they wanted to avid detection of the raid as long as possible.

Al the radio chatter between bombers in the movies... pretty much didn't happen.

[rifleman_btx]

Indeed

[Hardway]

Here are a couple more of the top turret. I drilled out the gun barrels... The turret ring and base is airbrushed interior green (FS 34151) by Model Master. The guns were sprayed in gunmetal and dry brushed in satin black from Ammo by Mig Jimenez . After a day or two of drying, a wash of black India ink and alcohol will bring out the vent holes in the barrel shrouds... The last pic is of the modified turret (top) and the stock turret (bottom). More details (gun sight, ammo belts, charging cables) to be added later!

[Hardway]

Here are a few of the main wiring harnesses from the batteries to the ESCs. 10 AWG wire and EC-5 connectors. 10mm heat shrink for the harness binders...

[fhhuber]

How long are those extension wires?

Generally bad practice to extend between the battery and ESC more than doubling the length that would have been between with the wires originally on both.
The potential issue is blowing up the ESC input capacitors, This issue is worse at partial throttle than full throttle. Exactly where its the worst is dependent on the resulting RC circuit frequency and the mosfet cycling frequency for the motor RPM. (like a harmonic sound frequency breaking glass)

The normal solution if the long wires are not avoidable is to add more capacitors (lots more capacitors) But that comes at the price of having t charge the larger capacitor bank and causing a much larger spark as you plug in the battery, which can arc weld or melt down your battery connector.

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If possible, its better to extend between ESC and motor.

[Hardway]

Well... They are 44" on the outboard nacelles... If I put 4- 100 amp ESC's and 4- 5000mAh 6s batteries in the fuselage, what kind of cooling is possible?? Could I use a fan like in a power supply?? If I run wires from the Power 60's to the fuselage, will that work? The motors have 12 AWG and the ESC has 10 AWG. I can't fit the battery and the ESC in each nacelle... That was the first thought... Any advice would be nice. I am crunched on time, especially if I have to start over on the wiring...

[Hardway]

I am looking for any experienced input. I have over 100 electric models flying. But I have no real life experience doing a giant scale conversion to electric, so please speak up and spare no feelings. No offense will be taken here. I just want the plane to fly with ALL of it's motors going, for the ENTIRE flight!!! LOL Thanks all in advance... :Sweating:

[Hardway]

Going to have a beer and regroup... :Straight-Face::Drinks::Cool:

[Twowingtj]

fhhuber has a valid point. Maybe one solution, if you have room, would be to put both ESCs in the inboard naccels with the long ESC to motor wires going to the outboard motors. You could then keep the batt to ESC wires shorter and still get air to the ESCs. What is the distance between battery location and the inboard motors?

[Hardway]

Still about 34", but can cut it down to 30" minimum... The inboard nacelles house the retracts and wheels... But I think I can make both fit there OK... Would a power supply cooling fan in the fuse work? Over the batteries and the ESC stack???

[Twowingtj]

Even 30" is a bit much. Cooling fans should work as long as you can get good air axchange. Other than a slight voltage drop, not sure what other issues you might encounter with the length of wires to the outboards. I've never tried a run that long.

[Hardway]

Thank you!! The battery leads on the giant LX B-25 are quite long from the ESC to battery in comparison to other set ups... So are the F-4 and the A-4..... Hmmmmmm Will have to work a compromise... The CC Phoenix 100 data didn't have any length of lead data either... :Confused:

[Ole-Timer]

If I had to, I’d move the esc’s into the fuselage to get them nearer to the batteries.
Read through the following link, there are some interesting tidbits therein.

https://www.rcgroups.com/forums/show...ns-workarounds

Before you make any move, contact Castle Creations support and get the straight scoop on battery to esc wire lengths for the Phoenix 100.
There is no substitute for directed ambient ram airflow to keep an esc cool. If they overheat in flight it could be disastrous.

Try and be mindful of weight at this point, don’t add anything you really don’t need.

[Hardway]

Thank you!!! I agree. I will call them in the AM... Ram air is good.... Heat is bad!!! LOL Really, I sincerely appreciate the help!!!!

[rifleman_btx]

Yeah it's kinda why all the pnp planes we get all have the escs right behind the props or in the case of edf somewhere in the airflow. So far I never had any issues with longer battery cables. Be it they were not that long as you will need...:Confused:

[Hardway]

44 inches is a little long!!!! I am stopping for today and going to reboot in the AM.... :Confused::Straight-Face::Thinking:

[Hardway]

Wish this was brought up earlier in the testing phase... But, it is great to have the data and be able to adjust now.....

[fhhuber]

My plan on a model that will need long leads is to place smaller packs in the nacelles and the big packs in the fuselage.

4X 3s 2200 surrounding each of the 2 EDFs and a total of 12S 10,000 mah in the fuselage. (12S 14400 mah total for 2 X 5000 watt EDFs, expected 4 min flight times.)
The 4X 3S 2200's will be the most I can get in the nacelles.
ESCs are integral to the EDF units I have and relocating them is not practical.

Plug the small packs to charge the ESC capacitors and then parallel everything.

With high C rated packs, the small packs will virtually eliminate the "inductive snap" (which is the issue of concern) from the long wires.

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Cooling packs in flight is not a big concern, without the ESCs in the fuselage.
Just pull the packs ASAP after landing

But the ESCs buried in the fuselage can cook the packs if you don't have cooling air.

Some will put the ESCs in the bottom of the wing beside the fuselage, making the wires from ESC to battery pretty short and the wires from ESC to motor long. This will be a bad idea for a pretty scale model.