Radio Upgrade Help Please

[joseywales]

After a mysterious 27mhz radio signal loss induced collision with a metal pole building (Cub survived luckily) I decided to ditch the stock electronics. I'm new to this and wondering what all I need.

I don't have a lot of coin to throw into this so I snagged this JRSport SX600 on Ebay for $89: cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=280225766755

It comes with servo's and RX. All I need then to run this with my 2150 3S Lipo is an ESC like this one, correct? www.horizonhobby.com/Products/Default.aspx?ProdID=GWSICS480

Is that all I need to make this work then? I want to keep the stock motor in for now. Any help would be appreciated! Oh and when they say 27mhz can be cut out by CB radios they mean it!

[sayers]

Hi
I am new at this also but have switched electronics , were you running the lio batt with the 27MhZ set up ?
If you were then you have already switched props , right ? From the 10X8 stock to 10X6DD. If you have not you should to keep the Amp Draw down. I am sure some of the experts will jump in here and tell me if I am wrong and what you need , but to me looks as if it should work.
Sayers ( Jerry )

[duck9191]

the problem that some had with the 10x8 on stock electronics with a lipo was that if you are a speed freak (who isn't) and cruised around with a bit to much throttle people were smoking the fet's in the stock receiver/esc. a 10x6 would be easier on the motor but there only $10 lol.

you don't want to use that esc with a lipo, the cut off is 4.2 volts, and on a 3s lipo could mean fire lol. you want this one ics-480-li its the same esc just lipo save-er. the cut off is still to low at 8.1 volts but it shouldn't kill the battery if you get distracted and fly to long. just try to time your flights.

*edit*

on horizions site it still list the cut off at 4.2 volts, but on the gws site ti says 8.1 volts. here is the link for the lipo one. again try to time your flights to try to keep the pack above 9 volts, it will help with the life span and is safer.

[flydiver]

8.1v on a 3S is still WAY to low. Personally I consider 9V too low. Most modern high discharge lipos are basically empty at 3v/cell. DO NOT believe resting voltage-not reliable or very accurate.

Since most ESC's do not have lipo safe LVC you need to learn to time your flights and bring it down with about 20% of the battery left.

Passing this along from another flier:
[4.20v = 100%
4.03v = 76%
3.86v = 52%
3.83v = 42%
3.79v = 30%
3.70v = 11%
3.6?v = 0%

Capacity below 3.7v "resting" is not usable for flying; it's where the battery voltage dump begins.
I have verified these results myself many times and simple fact is that the newer LiPolys do hold volts better under load so when a given LVC is reached they have even less capacity left in them.

For best life you should never use more than 80% capacity and resting / no load voltage should be a minimum of 3.7 per cell and 3.8 per cell is much better.]

fly

[joseywales]

;D Thanks for the quick responses!

I'll look into that Lipo Saver controller for sure! Thanks!

I noticed in the ebay description on that radio I bought it mentions that the "Switch Harness" is also available for sale. Do I need that also? It's here: cgi.ebay.com/JR-SPORT-JSP98010-STANDARD-SWITCH-HARNESS-SX600-S400_W0QQitemZ270235663726QQihZ017QQcategoryZ34056QQcmdZViewItemQQ_trksidZp1713.m153.l1262

Also, does anyone out there have that radio and know if I have to use the battery it comes with or can I use AA's? It doesn't come with the $30 charger, and I'd rather use my rechargeable AA's.

Yes I've been using the 3s Lipo in my stock cub. I only flew it twice, both times with the standard prop. I rarely go full throttle. I timed each flight at 15 minutes and checked voltage and it was at 10.8 or so.

I did buy some 10 x 6 props to try but I kind of like the power that the stock prop gives me. I like being able to take off and gain altitude quickly. Will I take a big power hit if I slap the 10 x 6 on?

I read on another forum where a fella said to cut 1/2" off each side of the stock prop. It brings Amp draw down, motor runs cooler, yet you still retain a lot of power vs switching to the 10 x 6.

So when I test my resting battery the lowest it should ever be is 9.6 then?

[duck9191]

check out ampaviators page here for some prop data on the stock brushed 480 on lipos. you lose about 50 grams of thrust and gain about 1500 rpm

the switch harness is just a external power on/off switch that you can put on the out side of the plane. so no you don't need it.

just noticed, i just bought a nitro truck from these guys, shipping's pretty fast.

[flydiver]

May 13, 2008 15:30:32 GMT 1 joseywales said:

I timed each flight at 15 minutes and checked voltage and it was at 10.8 or so.

I did buy some 10 x 6 props to try but I kind of like the power that the stock prop gives me. I like being able to take off and gain altitude quickly. Will I take a big power hit if I slap the 10 x 6 on?

I read on another forum where a fella said to cut 1/2" off each side of the stock prop. It brings Amp draw down, motor runs cooler, yet you still retain a lot of power vs switching to the 10 x 6.

So when I test my resting battery the lowest it should ever be is 9.6 then?

3.6x3=10.8 > you ran them to the safe edge. Can you do more?
Sure. Lipos don't cost all that much.

Yes, you can use a prop that's too big. Will it hurt? Not much. Lipos ESC's, and motors don't cost all that much. ;D

Funny how this sport is. Most of the 'valuable' lessons have to be learned the hard way.

fly

[joseywales]

Thanks for the info duck and flydiver!

I'm still a bit confused though. With the cub's electronics I plug in the one Lipo battery into the plane and it goes.

By upgrading to this JR radio do I need another seperate battery that powers the receiver in the plane in addition to the Lipo? And is that what the switch I mentioned in my first post is for? So this other battery doesn't stay ON all the time and kill the receiver battery?

[flydiver]

You don't need a separate RX battery. That is an option until you get to higher powered systems (4S + 4servos is kind of the line) or more.

The switch is not necessary. It does as you suspect and can be useful for some planes, especially if the battery is hard to remove an may be charged in place.

TX batteries are generally NiXX packs in higher end TX's. Mostly only cheap TX use loose AA's.
Manual for the TX www.horizonhobby.com/ProdInfo/Files/SX600_manual.pdf
A quick look appears though you'll need a JR charger, you do get the 700 battery. Charger is $30 more + shipping I'm sure.

READ THE MANUAL! The polarity on JR is reversed so if you get something other than their charger you can burn something up.

fly

[duck9191]

^^ ya deffintally read the manual, it will help alot. JR stuff is differnt then some other manufactures like the charging port, and that they are positive shift.

[joseywales]

Keen! I'll read the manual now!

Tnx for the heads up on the charger. I was thinking I'd buy a cheapo charger and Macgyver it to fit the battery but I think I'll just take the safe route and buy the $30 JR charger instead.

Thanks!

[joseywales]

I stumbled across another question. The JR RS6UL 6 Ch micro receiver that comes with this JRSport Sx600, I reckon I need a crystal for it. I can't seem to find any crystals on line for this puppy. Any ideas?

Also, do I then need another matching crystal for the TX? And out of curiosity, what kind of range can I expect from this setup? Anyone have any idea? Thanks!

[flydiver]

There are a number of rules about flying. Good to pay attention to.
There is one BIG one I have about buying RC- read BEFORE you buy. To NOT do so is generally to regret it later.

JR Xtals are a PITA. Hard to find, expensive. My LHS only sells them as an RX/TX pair. I contacted JR and they indicate you SHOULD send the whole unit in to be calibrated with any NEW TX Xtal. If you bought it guess you'll have to wait and find out what channel it is (or isn't). These guys have Xtals.
www.espritmodel.com/index.asp

There's often a reason stuff on eBay is cheap. Your unfortunately are finding out. I won't buy most ANYTHING on eBay anymore-place is getting so it sucks. The RC groups are MUCH safer, MUCH cheaper (if you study up a bit), and generally reliable. I found a TX (JR6102) with charger and upgraded battery for $100 from Wattflyer a year ago-cheaper now. You can get a number of comparable units for $80-120 often with an RX or 2.

Range should be farther than you can see your plane.

Expect to be TOTALLY baffled by the manual.

fly

[joseywales]

Thanks again Flydiver! I wish I would have scoped out Wattflyer etc first. I lucked out though, the TX and RX both came with crystals!

[flydiver]

Good! I'm sure that''s a relief.

For using it at first mostly what you need to know is control reversal in case you need it. Expo is very useful and dual rates can add a dimension. Later on if you get a delta type you'll need the elevon mixing. I was REALLY baffled by that for awhile. The JR books are minimally helpful and the concepts are brand new so it take awhile to catch on.

fly