In general, a 3-bladed prop should be 50% more "load" on the motor, and push 50% more air at the same rpm. This can be quite significant!

Originally Posted by THOMASJONES

10 minutes is definitely a joke for fpv.

Unless you fly aerobatic jets in formation... Then 10 minutes might be too long...

Originally Posted by ysolomon

Unless you fly aerobatic jets in formation... Then 10 minutes might be too long...

very true

Originally Posted by FPV_Habu_Flyer

Ok, sounds good, but what will happen if I stick with the NiCD pack that is included? Can I still expect decent range?

Keep in mind that I have never yet flown FPV. I am just going to stick to the basics. The guys at my hobby store said that Futaba radios have good range without LiPo packs but I'm not sure...

That sounds like complete hooey to me. Don't these radios run an internal regulator? You aren't actually sending more power to the circuits when your input voltage is high - you're just wasting energy in the regulator.

That said, I run the A123 packs in my radios and the convenience of being able to charge at the field, and the better overall performance makes it worthwhile to me. But I don't expect the radio to work any better - that sounds just a little bit crazy to me.

Originally Posted by jasmine2501

Don't these radios run an internal regulator? You aren't actually sending more power to the circuits when your input voltage is high - you're just wasting energy in the regulator.

Thats the way I understand it.

too high of a voltage can burn out the regulator

also stock batteries drop peak voltage fast and settle down to the recommended voltage for the rc tx

so if you use a lipo as an example charge it to the
'settleing down" voltage as lipo battery will not drop in volts like the stock one

you won't get further with more volts to the rc tx

Originally Posted by jasmine2501

That sounds like complete hooey to me. Don't these radios run an internal regulator? You aren't actually sending more power to the circuits when your input voltage is high - you're just wasting energy in the regulator.

That said, I run the A123 packs in my radios and the convenience of being able to charge at the field, and the better overall performance makes it worthwhile to me. But I don't expect the radio to work any better - that sounds just a little bit crazy to me.

FYI - I run a lipo in my Futaba 9zWc2. Because the radio was designed to operate with NiCD's originally, I use diodes to drop the voltage of the lipo. I am rather fond of my 9z, and decided to be safe and run the radio at the voltage it was designed for rather than risk it.

Quite right, you're not going to get any extended range with a higher voltage or bigger pack. At best you'll get the special edition infinitely shortened range version when the regulator or caps go *POP* from the excessive voltage (and heat).

You would know... * reads "magic smoke maker" from title... lol
P.s if you guys could take a quick look at my thread and give me some tips for my first fpv flight...

P.s.s OMG!! 500th post.?!!

Originally Posted by nft343

FYI - I run a lipo in my Futaba 9zWc2. Because the radio was designed to operate with NiCD's originally, I use diodes to drop the voltage of the lipo. I am rather fond of my 9z, and decided to be safe and run the radio at the voltage it was designed for rather than risk it.

I use a little DC/DC converter to bring the lipo voltage down to what the HF part requires. The digital part (in my radio) can cope with the lipo voltage and this gives the advantage that the voltage shown by the radio is still what the Lipo delivers giving me an easier way to check the stat of the lipo battery.

Markus

Originally Posted by jasmine2501

That sounds like complete hooey to me. Don't these radios run an internal regulator? You aren't actually sending more power to the circuits when your input voltage is high - you're just wasting energy in the regulator.

That said, I run the A123 packs in my radios and the convenience of being able to charge at the field, and the better overall performance makes it worthwhile to me. But I don't expect the radio to work any better - that sounds just a little bit crazy to me.

http://fpv-community.com/forum/showthread.php?tid=911

and:

https://fjallfoss.fcc.gov/eas/GetApp...html?id=388590 <--page 22

The transmitter's output power goes up proportional to the input voltage. I've read this many times elsewhere.

simply put, want more range? get more volts

Originally Posted by David22

too high of a voltage can burn out the regulator

also stock batteries drop peak voltage fast and settle down to the recommended voltage for the rc tx

so if you use a lipo as an example charge it to the
'settleing down" voltage as lipo battery will not drop in volts like the stock one

you won't get further with more volts to the rc tx

according to the FCC, you will get further with more volts to the TX.

Originally Posted by PLD

Quite right, you're not going to get any extended range with a higher voltage or bigger pack. At best you'll get the special edition infinitely shortened range version when the regulator or caps go *POP* from the excessive voltage (and heat).

I'm no IBcrazy, but from what i have read, the final amplifyer in a 7C is unregulated. This is where you get the boost in output power

Originally Posted by gundamnitpete

I'm no IBcrazy, but from what i have read, the final amplifyer in a 7C is unregulated. This is where you get the boost in output power

If that's the case, then yes, you might get some gains - that said you'll probably also will get a whole lot of spread on the noise too, as well as likely violating FCC limits. You will still also be at risk of burning out parts depending on how close to the edge they designed certain things.

Looks like it's a specific case only with that radio... although I do remember that my range was noticeably reduced when my Hitec would run low on power - yet another thing to hate about 72MHz I guess. I wonder if all the radios are like that - it seems dangerous to regulate the power output in that way.

But my point about the A123 battery is that you won't melt your radio with it - it has almost the same voltage range as the stock NiMH packs, and it has all those other groovy features, but I'm not convinced it's worthwhile to up the voltage over what the stock packs give. After all, what good is more range if the radio melts in your hands?

SOME THOUGHTS ON THAT FCC DOCUMENT


the FCC document shows this for a 7C:

8.16v - 297mW
9.60v - 375mW
11.04 - 442mW

Using some simple math (read:google calculators), we can extrapolate for a fully charged 12.6 volt lipo.

12.6 - 575mw

at 12.6 volts, you are looking at near 600mwmw of output power, which is double the stock power at 8.16 volts.

This will give you roughly 30% more range, in thoery.