Giant Heinkel 219 by Dave Platt
 

I'm sorta new to electric: 30+ years in large warbirds, however. After dinking around with some foamies, then "training" on the Otter you see in the background, I teamed up with my buddy Lynn to electrify this 121", 54 lb beauty built by Dave Platt some 10 years ago. I suspect he gave up on it because he couldn't fit a big enough piston engine in the cowls!

All is going well, but I am doing thorough testing on all components before I fly a museum-quality masterpiece

Engines have come down to Dualsky 6000 vs AXi5345 and I've put them both through a lot of props on the stand.

Using Castle Edge HV160's and 7.7 amp-hour TP 12S lipos.

I really like the way the AXi swings a Xoar 20x12 prop for > 8 minutes and I have experience with those props, that rpm range on some big gassers: CBA-38 and Ziroli P-61

But I'm also measuring motor casing temps, and the AXi 5345 alway goes to about 130 F and stays there for most of a mixed high throttle run.

Is that OK??

I started with the higher engine timing set-up advised by AXi: 20-25 degrees, backed off to 5 degrees at recommendation of Castle tecchie and a knowledgeable friend, didn't seem to make much difference

Help??
https://cimg7.ibsrv.net/gimg/www.rcu...3dda7eca60.jpg

Not an answer to your question, but since it's a twin model ...

Too long wires batteryside will kill ESC over time: precautions, solutions & workarounds - RCG
Contents

• Two problems
  ◦ Voltage spikes higher than battery voltage: transistor/FET/chip breakdown.
  ◦ Current through input capacitors too high: overheating/popping/exploding.
• Example: four costly controllers consecutively cremated :(
• Solution I: simply lengthen the motor wires instead :)
• Solution II: add extra capacitors, rules of thumb
  Calculation spreadsheet
• Capacitor type and polarity/orientation!
• How & where (not) to add extra capacitors
  As close to or on controller.
• DIY capacitor pack pictures
• Capacitor & pack suppliers
• Expert/manufacturer opinions & their rules of thumb
  They all say the same ... noise_reduction_101, switching_power_supply_design_101.
• Cause, explanation, water hammer/knock analogy&video, theory
  References
• Measurements & scope traces

Vriendelijke groeten, en wees voorzichtig ;) Ron
• Without a watt-meter you are in the dark ... until something starts to glow •
• e-flight calculators • watt-meters • high power motor tips&tricks • Cumulus MFC •

Thanks for a very thorough summation

I wrassled with a lot of that with big-twin planning last fall and made a critical strategic decision to install the motors completely independently, which obviates concerns about long wires, but of course raises concerns about differential power outputs and/or battery rundown.

so far in testing on the Otter and the big motors, side differential has NOT been a problem. But my lipo’s are relatively new.

My prop testing has been aggressive: 2 and 3 blade Xoars, Mejliks, Biela’s, Varios from Germany. Favorite so far is Xoar 20x12’s 2B. Getting peaks > 7,000 rpm, run times up to 9 minutes at high mixed throttle.

Still concerned about the AXi’s (which chew up less battery) heating up to 130° and above at high throttle. No answer from Espirit Models. Could it be my 12S lipo’s? AXi package insert says 8-12S lipo’s, “10S ideal.”

Thanks for your help. Experienced big motor guys MUCH appreciated

Mark