Krill Extra 330 LX building thread

[TazmanianDevil]

I've waited for a long time for the servos. Finally I've got them.
9 Savox 2270 brushless with 444 oz and 0.12 at 7.4V.
I'm going to use HV Fromeco regs and adjust them to 7.4V so the servos will get 7.4V constant.

Today I worked on the Stabs and elevator after all this s is what the IMAC plane is all about, the throws on the elev so after some thoughts Ive decide to use the 1" route.
It will give the most linear fill and with the right geometry it will even make the force bigger due to the leverage.
The slots I did will also be a way to cool the servos on very hot days.
I used a home made threaded rod with carbon as the pushrods and Dubro ball links.
Overhaul throw is 30 degrees up, 35 down.
I literally got the arm inside the skin to get enough throw yet still use 1" arm.

 

[HRRC Flyer]

Hey @TazmanianDevil,

How do you like Savox servo's? I've never used them before and I'm thinking about trying them on an old school 1/3 scale Lanier Laser I just bought.

Thanks

 

[TazmanianDevil]

Very good and precise servos.
I use only them.
Got very good experience with them.
I've got a plane with these 2270 with more then 400hrs.
Think about it.

 

[toysforbigboys]

sub'd

 

[Jlc]

Glad you got the servo's so I can see build progress. What batteries are you planning on using that need regulated?

 

[TazmanianDevil]

Fromeco Lion 7.4V 5200 mAh.
Also Hayin Lipo 7.4V 5000 mAh.

 

[HRRC Flyer]

Thanks @TazmanianDevil, I am seriously considering them

 

[bigblueswope]

Glad you got the servo's so I can see build progress. What batteries are you planning on using that need regulated?

I think he's regulating them so he always gets the same voltage on them which will give him consistent speeds.


BJ Swope

 

[TazmanianDevil]

And you are right.
I've noticed that when you use unregulated 2 cell the servos get straight 8.4 V at first, then it gradually getting lower up to 7.2v so...
1. The servos get the pick current 8.4 and not all can handle that.
They get jitter
My Savox 2270 can handle that and I did flew my planes without regs but then I've noticed that...

2. The power and the speed are not equal as you fly more and more.
The flight start to be less precise and crisp.

3. The servos wear and tear is up to 50% more.

4. I've noticed that the voltage drop is minimal so you don't have blow backs.

There are pros and cons with this regulated procedure
Pros...
1. Constant, straight and regulated current to the servos. They get 7.4 or less (what ever you diced) all the time so the power and speed are the same on all flights.

2. The servos wear and tear are to the manufacturer specs. 7.4v and you get the speed and power to the specs.

3. The voltage drop is minimal. No blow back

4. The regs monitors the amplified output voltage, adjusting the gain so that it is ruler flat over time.

Cons
1. You'll need to see that you don't have a voltage drop less than the one you fixed i.e. If you fixed the regs on 7.4 the regulator will work perfectly if you keep within the datasheet specs. If you supply it with less than 7.4V it will lose regulation.

I use a Fromeco cricket that measures the lowest voltage drop I have in every specific flight so, the lowest I had was about 6.9 and that was when the voltage got to 7.3 so when the batteries get to 7.5 I stop the flights and replace the batteries or charge them.
My plane gets to 7.4 after 6 15 minutes IMAC flights.
I charge them about 3000mAa.
proper disclosure I use Lipo 5000 mAa 30c batterie and try it with Fromeco Lion 5200mAa 8c as well.
Didn't see much change between them.

 

[dhal22]

Great thread. Enjoying the progress. Nice work by the way.