Electrifying models of the 70 Glow Size - WattFlyer RC Electric Flight Forums - Discuss radio control eflight

Sport Planes (Formerly I/C & Gas Conversion) Discuss I/C or Gas Conversions, Aerobatic Planes and Sport Aircraft

Electrifying models of the 70 Glow Size

Old 03-28-2009, 09:13 PM
  #1  
kyleservicetech
Super Contributor
Thread Starter
 
kyleservicetech's Avatar
 
Join Date: Apr 2008
Location: Wisconsin, USA
Posts: 8,952
Default Electrifying models of the 70 Glow Size

I'm the editor of the newsletter of a Milwaukee Area Radio Control club. Over the past year or so, I've put together a series of articles on medium powered electric models. These articles have been compiled to the attached 14 page PDF document.

The article covers the following items:

Four Stroke 70 Sized Electric Powered Models
Chapter I ---------Definition
Chapter II --------Field Charging Issues
Chapter III -------Selection of Hanger 9 Showtime 50 Model
Chapter IV -------Get Computer Software Help
Chapter V --------Evolution from Geared Astro 40 to Hacker A50 Motors
Chapter VI -------Results
Chapter VII ------BEC (Battery Elimination Circuits) Issues
Chapter VIII -----Power output vs Four Stroke 70 Glow Engines
Chapter IX -------Electric Power Prop Unloading
Chapter X --------A123 Cells
Chapter XI -------Showtime 90 Design
Chapter XII ------Electric Cost Issues
Chapter XIII -----Battery Life Span
Chapter XIV -----How to Kill a Lipo/A123 Pack
Chapter XV ------Editors On Board Monitor
Chapter XVI -----Charging Lipo/A123 Packs


This article may be of some benefit for those club members seeking to advance to medium sized electric models.

Dennis V
kyleservicetech is offline  
Old 03-29-2009, 12:48 AM
  #2  
BradT
Scale Nut Loves Biplanes!
 
BradT's Avatar
 
Join Date: Dec 2005
Location: Abbotsford,B.C.,Canada
Posts: 520
Default

Excellent article, Dennis. I haven't tried A123 cells yet, but they are a possibilty for my giant scale project, though it will initially fly with 6S2P 5000 Zippy H lipo's (actually, 4 3 cell packs, which can be used as 3S in other models, for economy). You've written a good, common sense approach to the subject.
BradT is offline  
Old 03-29-2009, 01:29 AM
  #3  
kyleservicetech
Super Contributor
Thread Starter
 
kyleservicetech's Avatar
 
Join Date: Apr 2008
Location: Wisconsin, USA
Posts: 8,952
Default

bradt
Thanks!
How much current are you planning on pulling? I've found that about 25-30 Amps per A123 cell is a good average amount of current to pull out of them. Go much higher, and your flight time gets rather short.

What ever you do, don't ever short an A123 pack out. The pack will ALWAYS win. (Don't ask how I know!)

One of these days, I'm going to add to my fleet of 12 ready to fly electrics, and try a Biplane! To give you an idea on how these perform, I've got a lead sled CAP232-46 model that weighs in at 7 pounds, with 30 ounces per square foot. Power is a Hacker A40-10L with a 16X12 APC-E prop, and 5S2P A123's. It gets off the ground in about 30 feet, and climbs up at about 50 degrees out of sight.
kyleservicetech is offline  
Old 03-29-2009, 05:23 AM
  #4  
Larry3215
Look out for that tree!!!
 
Larry3215's Avatar
 
Join Date: Mar 2006
Location: Gig Harbor, Wa USA
Posts: 7,061
Default

I couldnt agree with you more Dennis.

These are a couple of my recent large A123 powered foamy projects. They are not glow conversions, but they illustrate the point just as well I think

The Mega Capricorn weighs about 6.5 pounds (havent actually weighed it yet but thats close) and runs off a 6S1P A123 pack. Peak power is in the 8-900 watt range but flight times are a solid 6 to 7 minutes the way I fly. I spend most of the flight loafing along at 1/4 to 1/2 throttle.

The XXL Polaris runs off 6S2P A123 packs. It only weighs 7.5 pounds but the average power draw is a good bit higher. Peak power is 1250 watts and flight times are 8-9 minutes max. I tend to spend a lot more time at 3/4 to full throttle with this one. It looks better going fast



Larry3215 is offline  
Old 03-29-2009, 06:38 AM
  #5  
BradT
Scale Nut Loves Biplanes!
 
BradT's Avatar
 
Join Date: Dec 2005
Location: Abbotsford,B.C.,Canada
Posts: 520
Default

Larry, Ive followed your threads on both those models, and saw that they both perform very well, indeed!

Dennis, I hope to draw no more than 40A on my big Bird Dog, for a little over 1000W, but that will only give me a very scale power loading of about 50W/lb, as the r.t.f. weight will be about 20 lbs. I can't do much to lighten the model, as it's already built, and formerly ran on a large twin gasser. The 6S2P 5000 pack will be mounted right up inside the firewall, and may not add enough nose weight for this 108" span monster, but I've got to see if it can be done. She does have fully functional flaps, and I think I may be relying on them for both take-off and landing. My experience with large models of scale slow-fliers is that they don't need huge power to weight to perform like the real thing. The D VII in my avatar weighs a hair over 10 lbs, wing loading is 13oz/sq.ft., and power loading is only 60W/lb., and she'll do everything the real one could, which is all I want from a scale model. WW I fighters should NOT prophang!
Brad.
BradT is offline  
Old 03-29-2009, 08:22 PM
  #6  
kyleservicetech
Super Contributor
Thread Starter
 
kyleservicetech's Avatar
 
Join Date: Apr 2008
Location: Wisconsin, USA
Posts: 8,952
Default

bradt
Dennis, I hope to draw no more than 40A on my big Bird Dog, for a little over 1000W, but that will only give me a very scale power loading of about 50W/lb, as the r.t.f. weight will be about 20 lbs. I can't do much to lighten the

Hi Brad
You can run that 6S2P A123 pack at 55-60 amps all day with no problem. To give you an idea on power, that pack will turn a 16X12 APC-E prop at about 5900 RPM using a Hacker A50-16S motor. This setup hauls my 8 pound Hanger 9 Showtime 50 up at about 50-60 degrees until you can no longer see the model. The take off run is about 30 feet or so on short grass. It pulls about 48 Amps out of the battery. Flight time is limited to about 7 minutes, which takes about 60% out of the battery after a very acrobatic flight. I've found that the current drops to about 15 Amps or so just keeping it in the air, so at that current level, the model could fly 15 minutes completely discharging the battery.

Note that these A123 batteries quit like a glow engine! When they reach total discharge, they just quit, like in 15-20 seconds! (That is hard on them, as well as the Lipo batteries. Did it once though, the battery came out just fine, but landed the model off the field.)
kyleservicetech is offline  
Old 03-29-2009, 08:34 PM
  #7  
kyleservicetech
Super Contributor
Thread Starter
 
kyleservicetech's Avatar
 
Join Date: Apr 2008
Location: Wisconsin, USA
Posts: 8,952
Default

larry3215
Good videos!
I used to go to my local field, complaining about my "Underpowered Electrics" then take off in 25 feet and climb out at 45 degrees, and make 80 MPH passes over the field. That with an 8 1/2 pound airplane. Guess our club members got wise, these Electrics ain't what they used to be! More than a few of them went electric.
kyleservicetech is offline  
Old 03-29-2009, 11:01 PM
  #8  
rudderfeet
Member
 
Join Date: Feb 2009
Location: Central Ohio
Posts: 145
Default

Excellent article - quite comprehensive. Give those of us thinking about larger planes a lot to think about - whether to stay electric or go with a traditional engine.
rudderfeet is offline  
Old 02-06-2010, 06:26 PM
  #9  
182 STOL Driver
New Member
 
Join Date: Jan 2010
Location: Boulder City,NV & WHite Hills ,AZ.
Posts: 12
Default Just getting stared inn Electric motors

Flight:
My question deals of what kind and size Volts/mah, battery would be good for a speed 400 electric motor on a Mini Telemaster. I want to get my grand kids to fly out at the ranch. Don't need to Out of Sight (OOS in old free flight days) performance -just a simple school yard flyer. Thanks and try to send responses to my email [email protected]

Thanks
Bill Reid
Boulder City ,NV
182 STOL Driver is offline  
Old 04-26-2010, 06:31 AM
  #10  
bluzjamer
Member
 
bluzjamer's Avatar
 
Join Date: Apr 2010
Location: rhode island
Posts: 216
Default

Awesome job Larry! Thanks for sharing.
bluzjamer is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Turbojoe
ParkFlyers
91
12-13-2009 07:12 PM
tommytorino
Sport Planes (Formerly I/C & Gas Conversion)
0
11-06-2007 01:05 AM
Steve
Indoor & Micro Electric Planes
2
10-19-2007 05:08 AM
tushmiller
Hi-Performance and Sailplanes
6
10-20-2006 11:56 AM
Doppelganger
Warbird Electrics
6
04-10-2006 05:57 PM

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Quick Reply: Electrifying models of the 70 Glow Size


Contact Us Archive Advertising Cookie Policy Privacy Statement Terms of Service

Copyright 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.

Page generated in 0.06854 seconds with 14 queries