ORIGINAL: bjr_93tz
Hi David,
I was hoping to take the higher voltage, lower current route. Actually my test flight was with a 4Ah and 5.35AH pack in series [X(] for proof of concept before getting a couple of 5S ~3Ah packs if it all worked out. Oh yeah, you're right about it weighting a ton, it took a couple of landing approaches to get the final turn lined up with the runway as it was running wide in the slow turns. But in the air felt ok.
I see where you're coming from but on trike classics, 6s
is the high V/low A route. Low V/high A would be the 5s route. Going to 12s is really only a sensible proposition on 14 lb+ models which are designed for 1.6/2.1 glow or 50cc gas setups. Equivalently, the 2m current pattern designs are running 10s setups but on much bigger motors with 20" props!
I was just very disappointed the $200 scorpion motor couldn't just bolt in and work properly, but I was very happy with the flight performance however dealing with the bad vibes at certain rpm needs some nutting out. The magnet/stator arrangement for that particular motor results in very heavy cogging and I'm tempted to believe that's part of the issue as well. Even with the prop off you can feel vibes kicking in at different rpm.
I think the motor probably does just bolt in and work fine but it is a torquer and not designed for our 11" props. You're overdriving it on too small a load. Bring the cell count down to 6s or 8s and a 15-16" prop and it will do fine - just not what you're looking for. If the motor doesn't turn smoothly unloaded there is a chance something is loose or unbalanced.
All good fun experimenting with a 20+ year old, oil soaked airframe but it was enough to convince me that building a brand new one purpose built for electric is the better way to go. Every time I visit the Tower Hobbies website I see a 75AX staring at me and I'm pretty sure it'd bring my Curare back to life at the correct weight with less fuss but I think I'm done with IC from now on......
Putting a 75 or 95 AX porker on a Curare is sort of similar to the electric 300-400KV motors we're talking about. Take 4 oz of fuel out and install a 55 AX and it might be surprising. I find even the 65AX to be a bit too much fat but it's not hugely different weight wise to the vintage 61's. Hanno has approved the 55AX on the new ARF he's been involved with. I think it speaks volumes about light modern airframe power plants.
David