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Old Jan 12, 2013, 06:10 PM
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Canada, ON, Guelph
Joined Mar 2008
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Hey Dave,

Nice update. I do have one other question for you though related to your setup.
I have a couple of CC 85HV ESC's and being a newby am wondering if they would be adequate with your battery/motor setup.
Any thoughts?

thx
Dave
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Old Jan 12, 2013, 07:26 PM
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Well, I'm using a Castle 120, and I've checked this log several times while evaluating the various props that I've tested.

Looking at the log of the last seven flights using my current set-up (-6XS motor, 7S, 19X12 APC), although the "average" current draw is only 22 amps, the max current recorded during the seven flights was 109 amps. Also, the "average" watts is only 550W, but the max recorded in the seven flights is 2736W.

Of course we all know the peak amp and watt readings with electric systems are short lived, and come and go quickly. Also, I have a lot of experience with larger electric power systems on R/C models (10-14S powered helis), and by every reference I have on the MythoS, the power system is running "happy", and is nowhere near close to its full capacity. Temps are low, batteries are running easy, flight times are reasonable, however performance is unlimited vertical if you want it.

All that said, I'm not sure an 85 amp ESC with the lower 6S or 7S cell count would be enough? I'm pretty new to F3A models and their set-ups, but I gather 85 amps is common with 10S powered systems. But with the lower 6S-7S cell count, and the increase in current draw for the same performance, I'd think the 85 amp ESC might be a little thin???

Someone out there must have tried it you'd think. But I can't say for sure, having never tried it myself.

(-: Dave
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Old Jan 12, 2013, 09:26 PM
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Miramar, Florida
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The MythoS is the best flying plane I own, it may be the best and most neutral flying plane I've ever had, including the Comp-ARF and CAModels planes, it really is a head turner too, never stop staring at it myself sometimes at the field!

Jack
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Old Jan 12, 2013, 09:28 PM
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85 Amps won't leave you anywhere near enough head room, you really should go with nothing short of a 100 Amp controller. I also went with the HV 120 after killing a Jeti Spin 99 (on 6S)...

Jack
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Old Jan 12, 2013, 09:31 PM
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Canada, ON, Guelph
Joined Mar 2008
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Thanks for the information Dave and Jack. It gives me a better understanding of where I'm at.
I think I can get $50 for one of my CC85HV esc so that will offset the cost of going with a 120HV that you and Jack have in your airframes. The unique nature of this plane at my local club is going to be really cool.
Thx
Dave
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Old Jan 13, 2013, 11:42 AM
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Sverige, Värmlands Län, Filipstad
Joined Jan 2009
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Hi,

I prefer 20-30% margin how much ESC can handle acording to specifications compared to actual max amp in flight at full throttle. So far that has been good rule for me.
For example in my Sebart Wind S 50E I have a Castle Creations Phoenix ICE 100 and at full throttle in air I have 70 amp. Feel safer that way. I have just got a Sebart MythoS 125E and plan to use the new Hacker A60-7XS motor and 8 cell LiPo in this plane. Maybe I will try the new Hacker MasterMezon ESC, I just have to figure out how many max amp I need to have the ESC to handle with 20-30% safetymargin (probably the MasterMezon 115 opto is what I will select).

/Bo
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Old Jan 13, 2013, 03:42 PM
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Canada, ON, Guelph
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Myths

Hey guys thanks for all of the feedback.
I'm good to go and will get a CC120HV esc for my 7s setup with a Hacker 6XS motor.

Dave
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Old Jan 13, 2013, 04:09 PM
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Miramar, Florida
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Quote:
Originally Posted by DLEVETT View Post
Hey guys thanks for all of the feedback.
I'm good to go and will get a CC120HV esc for my 7s setup with a Hacker 6XS motor.

Dave
I love this ESC for a prop plane, the throttle response is awesome, no lag, no stutter, smooth as silk ;-)

Jack
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Old Feb 03, 2013, 11:48 PM
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Well guys I've been flying the pants off the mythos and I'm starting to notice some things.

I'm wondering if anyone else is too.

I notice that on a 6600 pack, I can do the P-13, and vertical is great initially, but I find that I have it WOT for the second half of the schedule, and I all but stop on the half knife edge square loop on corner , I can get the first leg, but the second leg just washes out. I'm starting to economise on the start of the schedule so I have enough to finish.

It does feel draggy, and that helps with the constant speed of things, but it does feel like it could use more power, and speed.

Anyone else find the same?
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Old Feb 04, 2013, 11:42 AM
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Miramar, Florida
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Quote:
Originally Posted by Curare View Post
Well guys I've been flying the pants off the mythos and I'm starting to notice some things.

I'm wondering if anyone else is too.

I notice that on a 6600 pack, I can do the P-13, and vertical is great initially, but I find that I have it WOT for the second half of the schedule, and I all but stop on the half knife edge square loop on corner , I can get the first leg, but the second leg just washes out. I'm starting to economise on the start of the schedule so I have enough to finish.

It does feel draggy, and that helps with the constant speed of things, but it does feel like it could use more power, and speed.

Anyone else find the same?
What battery are you using (brand and C rating)? You shouldn't be able to tell the difference between a fresh LiPo and one 50% discharged really, we're talking about a 5 to 8% decrease in voltage for a good, hich C pack. Is it possible it's you just getting used to the way it flys and adding more power on your own, I find myself doing that at times...

Jack
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Old Feb 04, 2013, 08:24 PM
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6600mah 30C continuous. Thats acutally a good point, I should try doing a reversed shedule and see if I have the problem from the outset, as well as at the end of the flight.

Just about got the snap and spin conditions right. Getting there, slowly!
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Old Feb 04, 2013, 08:59 PM
HAL... Open the damn doors!
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Quote:
Originally Posted by Curare View Post
6600mah 30C continuous. Thats acutally a good point, I should try doing a reversed shedule and see if I have the problem from the outset, as well as at the end of the flight.

Just about got the snap and spin conditions right. Getting there, slowly!
I've been using the 65C Thunder Power packs and I've noticed no drop in performance. High C-rated packs are not only for huge App draw but minimal voltage sag as well ;-)

Jack
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Old Feb 04, 2013, 10:47 PM
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I remember you saying you were using those, I couldn't justify the $350 price tag.
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Old Feb 11, 2013, 04:14 AM
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Joined Oct 2012
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I have put lots more flights on both of mine:
  • First is on 10s with 220kv EF Silver Bullet on 20.5 x 14 prop
  • Second is on 8s with 300kv Motrolfly on 20 x 13 prop
Both fly about the same and handle windy conditions fine. What I would say though is that the model doesn't need more than 2,500 ish Watts for full F3A performance - but on both these set ups it will pull more, but with no discernable performance boost (but greater battery drain). Flying 10s with 4,600mah Hyperions and completes P-13 with about 20% left if throttle managed sensibly (including windy conditions). But if over pushed, as with this set up in full 2m models, you will flatten packs and notice it in square loop on corner coming into Z. Flying 8s on 5,800mah Zippy's and story is the same.

For similar overall 'capacity' and 'power' on 6s as these 2 would need around 7,600mah

Gibbo
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Old Feb 11, 2013, 11:00 PM
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I'm getting that feeling
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