How did the change effect current at full throttle? From? To?
Current drawn is proportional to pitch¹ and diameter⁴.
(And proportional to voltage squared and Kv cubed. In a perfect world, assuming no voltage losses in battery, wires, controller and motor.)
This would give a change in current by factor (20/19)⁴ × (8/10) = 0,98. Slightly lower current, by 2%.

Vriendelijke groeten Ron
• Without a watt-meter you are in the dark ... until something starts to glow •
• e-flight calculators • watt-meters • diy motor tips&tricks • Cumulus MFC •

Originally Posted by ron_van_sommeren

How did the change effect current at full throttle? From? To?
Current drawn is proportional to pitch¹ and diameter⁴.
(And proportional to voltage squared and Kv cubed. In a perfect world, assuming no voltage losses in battery, wires, controller and motor.)
This would give a change in current by factor (20/19)⁴ × (8/10) = 0,98. Slightly lower current, by 2%.

Vriendelijke groeten Ron
• Without a watt-meter you are in the dark ... until something starts to glow •
• e-flight calculators • watt-meters • diy motor tips&tricks • Cumulus MFC •

While i dont have a watt meter i can definitely say efficiency went up. I got 6 flights in with the new prop and all used an average of around 300 mah less than with the xoar 19x10. Motor temps were around 115°f after landing and taxiing to the pits.
Only downside is speed i would like it to be somewhere between what i get with 19x10 and 20x8. The last 10% of my throttle doesnt really do anything with the 20x8

Originally Posted by scooby61

... i can definitely say efficiency went up. ...

Also due to larger prop diameter.

Originally Posted by scooby61

While i dont have a watt meter ...

That always scares me a bit Scoob (EE).

Without (the use of) a watt-meter you are in the dark.
Until something starts to glow

• To trust is good
• To calculate is better Will get you to say within 10%, i.e. IF the input is ok.
  e-flight calculators & propdata (compilation)
• To measure is a must
  Without a watt-meter you are in the dark. Until something starts to glow
  A watt-meter will more than pay for itself, several times over, your battery, ESC and motor will love you for it. After calculating, always check current when you have a new/changed setup. Will also help you find optimal setup. And it's a great tool for debugging your power train.
• And do keep battery-/watt-/multi-meter wires short
  too long wires batteryside will kill ESC over time: precautions, solutions & workarounds
• close out sale Hyperion Emeter II, originally +200$, with optical and electrical tach, servo tester, local&remote logging - RCG

Vriendelijke groeten Ron
• Without a watt-meter you are in the dark ... until something starts to glow •
• e-flight calculators • watt-meters • diy motor tips&tricks • Cumulus MFC •

Originally Posted by ron_van_sommeren

Also due to larger prop diameter.

That always scares me a bit Scoob (EE).

Without (the use of) a watt-meter you are in the dark.
Until something starts to glow

• To trust is good
• To calculate is better Will get you to say within 10%, i.e. IF the input is ok.
  e-flight calculators & propdata (compilation)
  
• To measure is a must
  Without a watt-meter you are in the dark. Until something starts to glow
  A watt-meter will more than pay for itself, several times over, your battery, ESC and motor will love you for it. After calculating, always check current when you have a new/changed setup. Will also help you find optimal setup. And it's a great tool for debugging your power train.
• And do keep battery-/watt-/multi-meter wires short
  too long wires batteryside will kill ESC over time: precautions, solutions & workarounds
• close out sale Hyperion Emeter II, originally +200$, with optical and electrical tach, servo tester, local&remote logging - RCG

Vriendelijke groeten Ron
• Without a watt-meter you are in the dark ... until something starts to glow •
• e-flight calculators • watt-meters • diy motor tips&tricks • Cumulus MFC •

Since i never go for absolute peak power i have never had an issue using temperature and batt usage to confirm my calculations. I calculate and then setup for no more than 80% of those calculations usually start near 60% and adjust up incrementally. I agree a watt meter is the only fully accurate way but as long as i stay well to the co servative side of max output never had any kind of meltdown.