logo
Thread Tools
Old 04-01-2021, 09:41 PM
Cessna195 is offline
Find More Posts by Cessna195
Registered User
Joined Apr 2021
1 Posts
Discussion
Electric Set-Up For Aero Works Cessna 195

I’m new to giant scale and giant scale electric. My Dad successfully converted a Top Flite 182 he built to electric, when he was 88! We are putting together an Aero Works 195 and he wants to convert it to electric. It is listed as 15-16 lbs, designed for a 30cc or 180 glow, 90” wingspan. Is a 120 motor too small or should we go with a 160? 80 or 100 ESC? 6S and 4S combination for 180 motor. What size motor, ESC and Battery set up should we use.? Thanks.
Cessna195 is offline Find More Posts by Cessna195
Last edited by Cessna195; 04-01-2021 at 09:47 PM.
Reply With Quote Quick reply to this message
Sign up now
to remove ads between posts
Old 04-02-2021, 06:59 PM
grosbeak is offline
Find More Posts by grosbeak
Illegitimi non carborundum
grosbeak's Avatar
Canada, ON, Ottawa
Joined Oct 2012
2,094 Posts
I have an RCGuys Cessna 150 that used to run on a 30cc engine, weighing 16.5 lbs. I am converting it to electric and while I haven't made the final decision, I am considering a 16 x 10 prop on a Rimfire 120 through an Cast Creations Talon 90 to a Tattu 6S 15C 8000 mAh LiPo.

I am brand new to electric and have spent the last couple of weeks learning all I could.
grosbeak is offline Find More Posts by grosbeak
Reply With Quote Quick reply to this message
Old 04-03-2021, 06:29 PM
Cessna340 is offline
Find More Posts by Cessna340
Registered User
United States, NV, North Las Vegas
Joined Dec 2020
64 Posts
16 pounds sounds heavy for 6S packs, but I'm far from an expert. Just learning electrics myself.
I didn't know they sold 15c batteries. I would think you would need 35-50C.
Either plane is not going to have any extra power.
Once you jump to 30CC electric motors and up, you need 10S-12S batteries and at least a 120HV ESC.
Thumb thru Extreme Flight's website (and others) and you will get an idea of their Xpwr motor combinations that they have tested that work.
Good luck and keep posting results.-
Cessna340 is offline Find More Posts by Cessna340
Last edited by Cessna340; 04-03-2021 at 06:37 PM.
Reply With Quote Quick reply to this message
Old 04-03-2021, 09:32 PM
grosbeak is offline
Find More Posts by grosbeak
Illegitimi non carborundum
grosbeak's Avatar
Canada, ON, Ottawa
Joined Oct 2012
2,094 Posts
Thanks for the feedback. The combo gets good results in eCalc.
grosbeak is offline Find More Posts by grosbeak
Reply With Quote Quick reply to this message
Old 04-04-2021, 06:20 AM
ron_van_sommeren is offline
Find More Posts by ron_van_sommeren
uomo ludens modellesticus
ron_van_sommeren's Avatar
near Nijmegen, Netherlands
Joined Apr 2009
161 Posts
Quote:
Originally Posted by Cessna340 View Post
... I would think you would need 35-50C. ...
Minimal C-rating needed also depends on capacity of battery.
C-ratingmin = currentmax / capacity
Divide manufacturer's C-rating by two, at least. Some ratings are pure nonsense.

More info about C-ratings, discharge rates, stickertuning and other blatant lies. Using uniform tests, getting published/reffered in opening posts:
Battery Load Test Comparisons - RCG (active thread)


Some excellent battery info
LiPo best care practices - post#8346 - RCG
Contents
  • Maximizing Cycle Life and Performance
  • Storage Facts
  • Fun Facts
  • Nerd Facts a.k.a Solid-Electrolyte Interphase (SEI) layer
  • Thermal Runaway
  • Results, Comparisons, and Lies exposed in opening posts

And there's this post#198 by Frank Siegert, about (yet) another advantage of heating a battery to body temperature, through and through, for about one hour. Before using and before charging. Not only voltage is higher and battery wear lower, but also ...
Short flight time is killing me - post#198


Want more background info?
Lithium Polymer Battery Technology - RCG
An introduction, with special consideration of RC model lithium batteries.
By dipl.-ing. Frank Siegert, a.k.a. RCG user bzfrank.

ron_van_sommeren is offline Find More Posts by ron_van_sommeren
Reply With Quote Quick reply to this message
Old 04-04-2021, 06:21 AM
ron_van_sommeren is offline
Find More Posts by ron_van_sommeren
uomo ludens modellesticus
ron_van_sommeren's Avatar
near Nijmegen, Netherlands
Joined Apr 2009
161 Posts
Below an excellent quote about motor selection.
From
brushless motors Kv?.
Quote:
Originally Posted by scirocco View Post
While an absolutely critical part of the system ...
... Kv is actually the item one should choose last.
  1. Decide your peak power requirement based on the weight of the model and how you want to fly it:
    Magic numbers for modellers.
  2. Pick a preferred cell count (voltage) and pack capacity for how to deliver the power.
  3. Pick a prop that will a) fit on the model and b) fly the model how you want - often as big as will fit is a good choice, but if high speed is the goal, a smaller diameter higher pitch prop will be more appropriate.
  4. Look for a size class of motors that will handle the peak power - a very conservative guide is to allow 1 gram motor weight for every 3 watts peak power.
  5. Then, look for a motor in that weight range that has the Kv to achieve the power desired with the props you can use - a calculator such as eCalc allows very quick trial and error zooming in on a decent choice. For a desired power and prop, you'd need higher Kv if using a 3 cell pack compared to a 4 cell pack. Or for a desired power and cell count, you'd need higher Kv if driving a smaller diameter high speed prop compared to a larger prop for a slow model.

The reason I suggest picking Kv last, is that prop choices have bounds - the diameter that will physically fit and the minimum size that can absorb the power you want. On the other hand, combinations of voltage and Kv are much less constrained - at least before you purchase the components.

So Kv is not a figure of merit, in that higher or lower is better, it is simply a motor characteristic that you exploit to make your power system do what you want, within the constraints you have, e.g. limited prop diameter, if it's a pusher configuration, or if you already have a bunch of 3S packs and don't want to buy more, and so on.

Minor lay-out changes by RvS

Vriendelijke groeten en wees voorzichtig, Ron
• Without a watt-meter you're in the dark ... until something starts to glow •
E-flight calculatorswatt-metersdiy motor tips&tricksCumulus MFC
ron_van_sommeren is offline Find More Posts by ron_van_sommeren
Last edited by ron_van_sommeren; 04-04-2021 at 12:02 PM.
Reply With Quote Quick reply to this message
Old 04-04-2021, 12:03 PM
ron_van_sommeren is offline
Find More Posts by ron_van_sommeren
uomo ludens modellesticus
ron_van_sommeren's Avatar
near Nijmegen, Netherlands
Joined Apr 2009
161 Posts
Better ignore the engine-motor equivalencies by manufacturers/sellers, usually lazy/bad advice.

E-motors are more flexible.
Engines (gas, 2-stroke, 4-stroke) are specced at high rpm e-motors can rev lower, turning more efficient props.

Prop- and voltage-ranges: higher voltage goes with low load prop, lower voltage goes with the high load prop. Not the other way around, will ruin motor because of too high a current.

Good/realistic numbers and ratings on www.innov8tivedesigns.com, Lucien Miller does al the testing himself.


Vriendelijke groeten en wees voorzichtig, Ron
• Without a watt-meter you're in the dark ... until something starts to glow •
E-flight calculatorswatt-metersdiy motor tips&tricksCumulus MFC
ron_van_sommeren is offline Find More Posts by ron_van_sommeren
Reply With Quote Quick reply to this message


Quick Reply
Message:


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools