Li_po's what do I need to get started?    Gallery
View related threads: (in this forum | in all forums)

Logged in as Guest



Users viewing this topic: none
    Search This Thread  
 
Printable Version

All Forums >> Electric Aircraft Universe >> E-Flight Power Sources >> Li_po's what do I need to get started?
Page: [1]

Tower Hobbies Today's Special Offer! Brands Products
Login
Message << Older Topic   Newer Topic >>
Li_po's what do I need to get started? - 12/20/2003 9:07 AM   
usairdave


 

Posts: 6
Score: 100
Joined: 12/20/2003
Last Login: 12/9/2004
From: west newton, PA, USA
Status: offline 		I order a Sig Lil Rascal and would like to use li-po batteries. I am new to electric. Sig says the motor needs a 8.4v nimh but a lipo is only 7.4 nominal. What all do I need to power this plane? I have a Great Planes Triton charger.
Dave

Hide Signatures
       Post #: 1

RE: Li_po's what do I need to get started? - 12/20/2003 6:07 PM   
Greg Covey



Posts: 5589
Score: 133
Joined: 5/24/2003
Last Login: 5/21/2012
From: Rochester, NY, USA
Status: offline 		Hi Dave,

Here are the specs. on your Sig Li'l Rascal ARF

Wingspan: 29.75in
Wing Area: 134in2
Length: 20.5in
Flying Weight: 8.5 - 9.5oz
Motor: Speed 180 (included)
Gearbox: 2.9:1 (included)
Battery Req: 7 cell, 300 mah NiMH battery pack
Radio Req: 3 channel, 2 micro servos.

The 180 motor, if it comes with the plane, is likely similar to a GWS IPS motor. A 2-cell Kokam 340SHC pack would work nicely here. It is very light (0.8oz) and can supply up to 6amps continuous which would power much larger motors.

You are comparing an unloaded NiMH pack voltage with a loaded LiPoly pack voltage so it is "apples and oranges". Not to worry, the Kokam 340pack will easily outperform a 7-cell, 300mAh NiMH pack.

Good luck!

_____________________________

Visit my Web Hangar at www.gregcovey.com/rc.htm

Hide Signatures

(in reply to usairdave)
       Post #: 2

RE: Li_po's what do I need to get started? - 12/21/2003 5:28 AM   
usairdave


 

Posts: 6
Score: 100
Joined: 12/20/2003
Last Login: 12/9/2004
From: west newton, PA, USA
Status: offline 		Thanks for the info. Does the speed controller regulate the power to the reciever and servos?

Dave

Hide Signatures

(in reply to usairdave)
       Post #: 3

RE: Li_po's what do I need to get started? - 12/21/2003 10:21 AM   
GordonFreeman



Posts: 119
Score: 100
Joined: 12/20/2003
Last Login: 10/22/2008
From: Ironhorse, WI, USA
Status: offline 		I have a new hummingbird with the 8.4 NiMH AAA pack (600 mAh I think). The power to weight (I have a big old 7 channel receiver taking up too much space and weight I'm sure) seems a little anemic, it can barely get out of ground effects. I was thinking of getting a 3S lithium, but you are saying that a 2S lithium would probably supply more power (than the stock 8.4 NiMH AAA pack)? That would be great if I could have just a little more power and a little less weight.

Thanks
John

< Message edited by GordonFreeman -- 12/21/2003 7:24:05 AM >

Hide Signatures

(in reply to Greg Covey)
       Post #: 4

RE: Li_po's what do I need to get started? - 12/23/2003 6:00 PM   
Greg Covey



Posts: 5589
Score: 133
Joined: 5/24/2003
Last Login: 5/21/2012
From: Rochester, NY, USA
Status: offline 		Dave,

Yes, the ESC powers the receiver and servos via the throttle channel connection. In any receiver, all the plus (+) and all the ground (-) connections are routed together on all channels via a bus. This can be seen by plugging your receiver battery into any channel during the servo testing and centering phase of building.

John,

This will likely be the case if you switch to a 2-cell Lithium pack. They tend to hold their voltage better than AAA NiMH cells. Alternatively, if you still don't get the power you need, you can increase the prop size or pitch a bit.

Often, I have found that just the weight reduction alone makes enough of an improvement in how the model flies.

Good luck!

_____________________________

Visit my Web Hangar at www.gregcovey.com/rc.htm

Hide Signatures

(in reply to GordonFreeman)
       Post #: 5

RE: Li_po's what do I need to get started? - 12/24/2003 4:31 AM   
Jason W M


 

Posts: 154
Score: 100
Joined: 3/26/2002
Last Login: 11/18/2011
From: Las Vegas, NV, USA
Status: offline 		Hello Dave,

I fly a number of models the same size and using the same motor your LiL Rascal does (I also fly a Speed 400 sized Rascal - GREAT looking and flying airplane!).

For these models, I use the Thunder Power 2 cell 730 mAh pack. It weighs only 1 ounce - barely .2 ounce more than the 340 pack, but with more than twice the capacity! This pack can also handle larger motors - Ive used it on speed 280 and some mild 300s with excellent success. With your Rascal and this pack, flight times will be in excess of 30 minutes with ease! You could also use the new 830 mAh cells if you want even more flight time - they only weigh .1 ounce more than the 730s!

I too use 2 cell LiPo packs in the place of many 7 cell NiMh packs. I fly a number of micro helis using the stock motors with 2 cell packs - and they have noticeably more power than the stock 7 cell packs did! One benefit is the huge weight reduction - the 7 cell AAA packs weigh around 3.5 ounces. The Thunder Power 1320 mAh 2 cell pack weighs in @ less than 2 ounces with nearly double the capacity! I get 20-25 minutes per charge with this pack!

When Im indoors, I now fly the new Thunder Power 2 cell 830 mAh packs. This pack only weighs 1.1 ounce and is capable of 7-8 amps continuous draw (9-10C) - perfect for micro helis indoors where the low weight helps keep the heli more nimble. Even though the capacity is just barely more than the stock 7 cell packs, the lighter weight allows me to get over 10 minutes using this pack. Pretty impressive power and duration for such a tiny battery that is under $30! To lose the weight of your big Rx, try one of the GWS Pico receivers. Theyre only $19.99 and weigh around .25 ounce - I use this Rx in my Hummingbird too - hard to beat the size and price with anything else!

Any of these packs and the Kokam 340s would make a great choice for the Rascal!

< Message edited by LVRCFlyer -- 12/24/2003 1:35:14 AM >

Hide Signatures

(in reply to Greg Covey)
       Post #: 6

RE: Li_po's what do I need to get started? - 1/1/2004 9:29 PM   
thejc


 

Posts: 69
Score: 100
Joined: 9/14/2003
Last Login: 12/28/2008
From: delta, OH, USA
Status: offline 		contact dave thacker radical rc good person to do bussiness with always willing to help

Hide Signatures

(in reply to Jason W M)
       Post #: 7

Page:   [1]
All Forums >> Electric Aircraft Universe >> E-Flight Power Sources >> Li_po's what do I need to get started?
Page: [1]





Jump to:


 
Google 



Search | Marketplace | Event Calendar | Local Clubs | Magazine | Product Ratings | New Products | Discussion Forums

Photo Gallery | Instructor Search | Field|Track|Marina Search

Advertisers | Hobby Vendor Resources | Rate Manufacturers | Sign In/Sign Up

SITE MAP!   : :   FORUM RULES

RC Universe is a service of Internet Brands, Inc. Copyright © 2001-2012.

Charities we support that also need your help
Yorkie Rescue | Humane Society | ASPCA | Crohn's-Colitis America


0.516RCU1