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View Full Version : Stuka kit but help on the Axi4130..


Opcod
02-27-2006, 12:19 AM
Hi

So i will try myself to do a Stuka kit from Skyshark. I also view on the other thread:
http://www.wattflyer.com/forums/showthread.php?t=882&page=2

about people use the Axi 4130/16. But me, i have now the Axi4130-20 and 2 lipo 3s4p. So i whant to know: what i understand is the 4130/20 is much power hungry vs the 4130/16. Does it will be better to use and buy a 4130/16 with a 15/8 prop for being more powerfull ??

Also, the team of skyshark told me that the plane will be the best with a 4120/18.

Thanks in advance

Cubano8
02-27-2006, 01:33 AM
If your plane comes out around the 6lb range that Skyshark posts, then you will be OK with the AXI 4120. In fact I have flown a plane, 8lbs with a 4120, and flew good. I have also used a 4130 on an 8 1/2lb plane with a 16x8 prop, and it flew with authority(plenty of power).
I'm in the process of building a Skyshark FW-190, and I'm going to use a 4130 with two 3s3p 6000mah packs in series. It should give me more than enough power, if it comes out in the 6 to 7lb range.

rcers
02-27-2006, 02:46 PM
3s is not enough voltage for either of these motors. Do you mean 6s???

You will need at least 4s packs (most use 5s) with the 4120 and 5s-8s for the 4130. Remember these are monster motors....

Mike

Ron
02-27-2006, 04:45 PM
I use the 4130/20 in a 10 lb model on 20 round cells. It swings a prop that's 18X12 ( APC electric ) and the model just rips off the ground.

I also use this motor with a 2 to 1 reduction on 20 round cells...this swings a 30 X 14 hand carved prop on a 10 1/2 pound 30% DR1 it produces over 12 pounds of thrust....this motor has lotsa poop.

I have a friend who uses the 4130/16 on a Hangar 9 P 51 ( Miss America) ...it flies on 6S lithiums and is a no compromise model in the power dept....I believe he swings either a 16 X 10 or a 15 X 10 4 blade prop. Not positive which of the two it is, but it is definitely 4 bladed.

Opcod
02-28-2006, 12:58 PM
Thanks for the input.

Of course, the power will be 2 lipo in series that give the 6s4p... I will also plan to use a 3 blades prop: a 16x8 that is supposed to equal a 15x8 prop, if i'm right.

*Cubano8, if you can post a topic with your project fw-190 update, it can be interesting to see your work.

rcers
02-28-2006, 02:27 PM
Of course, the power will be 2 lipo in series
That is why I was confused 2 lipo in series is commonly designated as 2s. What you have is a 6s pack (6 cells in series). I think we are all on the same page now....

A three blade prop should actually be smaller. A 16x8 two blade is about (roughly) the same as a 15x7/8 three blade. All props are not created equal so much testing may be in order.

Mike

Cubano8
02-28-2006, 07:35 PM
*Cubano8, if you can post a topic with your project fw-190 update, it can be interesting to see your work.

Well, I can't really start a thread on the build since it's already half built, but here's where I'm at with it..

The top wing is already sheeted. The Bottom wing has the two gears(Robart air) already installed. Also I added split flaps to the wing, controlled by the Hitec slim servos( shown in the pics). The fuselage is 3/4 complete, and included is a pic of where the two 3s3p are going to be placed. I still have a lot of work on the plane, but most of the hurdles have been overcome.

Opcod
03-03-2006, 07:11 AM
Prety good work up now. What is the model of your robart, it's in the 3xx series ?
Also, go fly without air system, does the weel will stay in place all the flight and you will be able to land also ? ( So does the retract always need a certain amount of pressure, to not closing by itself ? ) Just whant to know

Cubano8
03-03-2006, 03:09 PM
This is the model of the robarts: 606HD
http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXES05&P=0

Here' what I use for the struts:
http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXES70&P=0
http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXES71&P=0

If there is an air leak while I'm flying, and I run out of air in the air tank, then yes the gear will remain in the last position. Theses retracts need air pressure to close and retract them.

Now you could go with the spring air, as the Skyshark web page advertises, or robart has a spring/air system too:
http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXJZD4&P=0

I've only used those robart spring air on my P-47(pic Included), and I dont like the way they spring down, too fast. With the air system that I'm going to be using on the FW-190, I can control the air flow in both directions.

So what have you finally decided on the motor? Would like to see your build/progress, I'm thinking of getting this kit.

Opcod
03-04-2006, 12:30 AM
Hi

Thanks for all the info. it's welcome. But the retract was not for the Stuka, of course. So i really don't know when, i had school and work all the time. But during the summer, i will start a plog on that.
Also, i will try my 4130-20, i have it, so we will see.
Let us know when you got yours in the air .

CorsairJock
03-21-2006, 01:04 PM
...............I have now the Axi4130-20 and 2 lipo 3s4p. So i whant to know: what i understand is the 4130/20 is much power hungry vs the 4130/16. Does it will be better to use and buy a 4130/16 with a 15/8 prop for being more powerfull ??
Also, the team of skyshark told me that the plane will be the best with a 4120/18.
Thanks in advance

I think your motor choice is a good one, and I assume that when you state "2 lipo 3s4p", you intend to run 2, 3 cell packs in series, thus creating a 6S pack. If so, again I agree with your choice.

In a nutshell: the 4130/20 will swing a bigger prop, but at slower RPM than the the 4130/16 (at a given voltage). It is NOT more power hungry than the 4130/16. Thus, the 4130/20 will swing a Master Airscrew 3 blade 16 x 8 while pulling only about 32 amps, and proving over 6.5 lbs of thrust (static), which should be plenty for your Stuka AND it will look VERY scale.

I obtained those specs by using the calulator at this site:
http://brantuas.com/ezcalc/dma1.asp

I 'plugged in' 6 Kokam 3200 Li-Po cells. As you will see, they have both motors (4130/20 AND 4130/16), so you can compare for yourself.

Again, let me state: your power choices thus far have been very good, and I would probably would have chosen the same.

My big electric warbird: AXI 4130/16 powered highly modified H-9 Corsair (swinging only 14" props).