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E Flite Eratix 3D 25e ARF Owners Club

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Old 01-09-2009, 01:44 AM
  #51
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Default RE: E Flite Eratix 3D 25e ARF Owners Club

Guys - thanks for the advice re. hinging - as you said, not actually that hard a job once you've done it!

I have another question for anyone who might know - I am getting near the end of the build, and when I installed the motor I realized that the firewall/mounting point for the motor is offset and angled, i.e. it appears to mount the motor slight off-center (to the left), and point it slightly to the right. Is this correct? I know that gas and nitro planes usually have a slight thrust angle, but I thought that (for some reason) electrics did not. My Eratix seems to have quite a pronounced thrust angle.

Did any of you see the same thing in your builds?

I appreciate any comments...Chris
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Old 01-09-2009, 09:49 AM
  #52
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Default RE: E Flite Eratix 3D 25e ARF Owners Club

This is normal and need with all EP/Nitro. Remember brushless motors are very strong and when you swing a prop like the eratix requires it will cuase thrust and having the correct angel will offset this thrust.

Good luck on your build, I know you wont be disappointed with the Eratix, its a monster.
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Old 01-09-2009, 03:52 PM
  #53
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Default RE: E Flite Eratix 3D 25e ARF Owners Club

Thanks! See you at the flying field - I'll be the guy veering down and to the right!
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Old 01-10-2009, 01:32 AM
  #54
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Default RE: E Flite Eratix 3D 25e ARF Owners Club

More questions - I roughly finished my build to check out servos, programming and CG. AUW no battery comes to 47 ounces, which is fine, except, even using a 14-ounce 4S pack and sliding it far forward in the battery compartment, the CG is still too far aft. This may be partly caused because I am using a Scorpion 3020-12 @ 5.5 ounces rather than a Power 32 at 8.5 ounces. The Scorp motor is out on 1-inch spacers to match the cowl, but the CG still seems to far back.

Anyone else have much trouble with CG?

Thanks!...Chris
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Old 01-10-2009, 01:08 PM
  #55
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Default RE: E Flite Eratix 3D 25e ARF Owners Club

Nope.
Power 32, Castle Phoenix 60 and a five cell A123 pack, plus four DS3421 (MG) = AUW 3 lbs 12oz and the CG is right where you would want it.

I have more than one with the self same figures. My CG is on the wing tube and I have adjustment space even then.
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Old 01-10-2009, 01:13 PM
  #56
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Default RE: E Flite Eratix 3D 25e ARF Owners Club

Anybody having problems with wing rocking on harriers? I have been unable to stop them.
My Eflite Diamante 25E is rock solid on harriers, so I must not have the Eratix balanced properly, right?

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Old 01-10-2009, 01:18 PM
  #57
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Default RE: E Flite Eratix 3D 25e ARF Owners Club

I'm a Pattern guy who happens to find the Eratix a completely FUN airplane.

Try reflexing the airfoil.
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Old 01-10-2009, 09:33 PM
  #58
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Default RE: E Flite Eratix 3D 25e ARF Owners Club


Quote:
ORIGINAL: onewasp

I'm a Pattern guy who happens to find the Eratix a completely FUN airplane.

Try reflexing the airfoil.
I agree, the Eratix is awesome and, actually, quite easy to fly.

As to"reflexing the airfoil", I don't know what you mean. Please explain.
Thanks,
Jmir
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Old 01-10-2009, 09:45 PM
  #59
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Default RE: E Flite Eratix 3D 25e ARF Owners Club


Quote:
ORIGINAL: onewasp

I'm a Pattern guy who happens to find the Eratix a completely FUN airplane.

Try reflexing the airfoil.
OK, I read up on reflexing regarding wing design. I have my ailerons following the bottom line of the wing, so they are slightly turned up. I'm going to change this, by making the wing fully symetrical and see how that affects the wing rocking problem I'm having.
I have flaperons programmed, so I can switch the position of the ailerons while doing harriers to see what the effect is.

Thanks for the tip!
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Old 01-10-2009, 10:32 PM
  #60
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Default RE: E Flite Eratix 3D 25e ARF Owners Club

Very interesting stuff! Like you, I have set my ailerons to be as symmetrical to the wing as possible - thinking being that it will make inverted flight as similar to normal as possible.

I've also tried programming flaperons on a few planes, with limited success - unless you are already experienced at it, I suggest a fairly small amount of flap to start with.

Godd luck...Chris
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Old 01-10-2009, 10:47 PM
  #61
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Default RE: E Flite Eratix 3D 25e ARF Owners Club

Chris , awaiting your maiden with the Scorpion Motor. I have been looking at them with interest lately. I have the Eratix with a Power 46-60 AMP ESC (E-Flite)13X8E APC Prop-TP 4S 3850MAH Battery Pack. My power is GREAT, I just think I could cut some weight and increase watts at the same time. Really, I think I am just looking for an excuse to get a second Eratix !!!-[color=#990000/color]WOODIE
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Old 01-10-2009, 11:15 PM
  #62
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Default RE: E Flite Eratix 3D 25e ARF Owners Club

Woodie - Biggest drawbacks to its first flight are:

1) Snow and hideously irritating cold weather.
2) CG - since last night I am thinking of ways to get the cg forward - the 3 ounce weight loss by using the Scorpion is obviously an important contributor - my ESC weighs 2.6 ounces and could move forward a couple of inches, and the AR6200 receiver and Castle UBEC hardly weigh anything, so I don't have a lot to work with. As the weight is currently nice I want to avoid adding any more weight as much as poss.

- I will, however, run some bench tests in the garage to see what propellers get what kind of wattage - don't have a thrust gauge unfortunately. I will post the details here if you are interested. I will have to hold onto the Eratix to avoid it flying off the bench, and/or the propwash blowing the dog's eyebrows off.
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Old 01-10-2009, 11:55 PM
  #63
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Default RE: E Flite Eratix 3D 25e ARF Owners Club

Chris, I WOULD definitely like to see the results with different props and readings. Do you have a wattmeter to gather the info???MANY THANKS-WOODIE
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Old 01-11-2009, 12:19 AM
  #64
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Default RE: E Flite Eratix 3D 25e ARF Owners Club

Woodie - Here are the figures from Scorpion. As you can see, you can reasonably get 600 watts from a 3S if you can handle 60+A, and a 4S with an 11x5.5 takes you to FunkyTown (800 watts - i.e. 200 watts/pound)

I am going to try it with an 11x7 and 4S. Will let you know if we survive...Chris
- - - - - - - - - - - - - - - - - - - -
Scorpion 3020-12 Prop Data 12/01/08

Wind - 12T Delta Motor Kv No-Load Current Motor Resistance Motor Weight
( 20 x 0.21mm Wire ) 1088 RPM/Volt Io = 2.24 Amps Rm = 0.029 Ohms 152 gm, 5.36 oz

Prop Prop Input Motor Watts Prop Pitch Thrust Thrust Thrust
Manf. Size Voltage Amps Input RPM Speed Grams Ounces G/W

APC 8x4E 10.5 11.58 121.59 10425 39.5 718 25.33 5.91
APC 8x6E 10.5 16.75 175.88 10100 57.4 836 29.49 4.75
APC 8x8E 10.5 23.77 249.59 9675 73.3 812 28.64 3.25
APC 9x4.5E 10.5 16.64 174.72 10125 43.1 1033 36.44 5.91
APC 9x6E 10.5 20.35 213.68 9875 56.1 1126 39.72 5.27
APC 9x7.5E 10.5 26.75 280.88 9475 67.3 1219 43 4.34
APC 10x5E 10.5 23.81 250.01 9775 46.3 1389 49 5.56
APC 10x7E 10.5 29.56 310.38 9425 62.5 1510 53.26 4.87
APC 10x10E 10.5 46.71 490.46 8375 79.3 1165 41.09 2.38
APC 11x5.5E 10.5 32.05 336.53 9275 48.3 1773 62.54 5.27
APC 11x7E 10.5 38.65 405.83 8825 58.5 1906 67.23 4.7
APC 11x8E 10.5 42.22 443.31 8650 65.5 1738 61.31 3.92
APC 11x8.5E 10.5 43.81 460.01 8575 69 1861 65.64 4.05
APC 11x10E 10.5 49.69 521.75 8125 76.9 1638 57.78 3.14
APC 12x6E 10.5 41.93 440.27 8650 49.1 2185 77.07 4.96
APC 12x8E 10.5 50.33 528.47 8075 61.2 1905 67.2 3.6
APC 12x10E 10.5 56.37 591.89 7675 72.7 1979 69.81 3.34
APC 13x6.5E 10.5 52.89 555.35 7875 48.5 2483 87.58 4.47
APC 13x8E 10.5 56.94 597.87 7650 58 2402 84.73 4.02

APC 8x4E 14 19.37 271.18 13575 51.4 1252 44.16 4.62
APC 8x6E 14 29.22 409.08 12875 73.2 1381 48.71 3.38
APC 9x4.5E 14 28.38 397.32 13000 55.4 1783 62.89 4.49
APC 9x6E 14 32.96 461.44 12650 71.9 1916 67.58 4.15
APC 9x7.5E 14 48.31 676.34 11975 85 2019 71.22 2.99
APC 10x5E 14 40.78 570.92 12375 58.6 2366 83.46 4.14
APC 10x7E 14 49.23 689.22 11800 78.2 2479 87.44 3.6
APC 11x5.5E 14 54.47 762.58 11425 59.5 2913 102.75 3.82
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Old 01-11-2009, 12:23 PM
  #65
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Default RE: E Flite Eratix 3D 25e ARF Owners Club

jmir

By reflexing I am suggesting that you set up the flap switch for "both ailerons up at position zero" and then "both ailerons down at position two".
position one will be dead straight.

I use 15 degrees as the max initial setting (that happens to work well for me) and then 'adjust to taste from there' (That is 15* up on position zero and 15* down as position 2 while position one is no deflection).

These settings are often called "Spoilerons" and "Flaperons". Those names however apply only to the end result when used at certain points in the flight sequence. We are going to use them elsewhere.

The "reflex" results in a change in the effective angle of attack "AOA".
With both ailerons raised in high alpha upright flight (with appropriate throttle use) what I am labeling the effective AOA becomes less than the actual wing's apparent AOA.

Through the "reflex" we have added "wash out" to the full wing so the theoretical stalling of the wing (tip section for purposes of visualization) is far less than the observed AOA during the high alpha flight.

Inverted flight in high alpha uses Switch position two. This creates the same condition as we had in upright flight with Switch position zero.

Clear as mud, right ??????

Not all aircraft will respond positively to this 'adjustment'. However, I have found that MY Eratix does.
For reducing the 'pucker factor' I suggest you start the flight experiment at 'one mistake high'.
DO NOT resume level flight without returning the settings to zero (or switch position one).
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Old 01-11-2009, 05:39 PM
  #66
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Default RE: E Flite Eratix 3D 25e ARF Owners Club

Anybody flying it with a glow engine? I am thinking about putting an OS 46AX. Any thoughts?
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Old 01-11-2009, 05:48 PM
  #67
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There is NO way it would handle the vibration!!!

With a .25 or .32-.36 engine I'll give you three flights MAX.

With a .46 I doubt you will get one complete flight.
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Old 01-11-2009, 06:34 PM
  #68
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Default RE: E Flite Eratix 3D 25e ARF Owners Club

Thanks for your feedback but I think I'll take my chances anyway and go with the .46. I don't want to spend a fortune on lipos and I already have the OS. However, I'll reinforce the firewall as well as other high stress areas.
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Old 01-11-2009, 07:16 PM
  #69
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Default RE: E Flite Eratix 3D 25e ARF Owners Club

I am quite familiar with the airframe. My first question is just exactly what do you think you can glue 'supports' to ?????
There is almost nothing there.

What you can find is 2mm ply about 6mm wide. That's the 'heavy' part of the fuselage construction.
It becomes a lot lighter from there on.

Do as you like but it is a waste of time and money IMO.


BTW, please take some pictures. I want to SEE this!
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Old 01-12-2009, 09:34 AM
  #70
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Default RE: E Flite Eratix 3D 25e ARF Owners Club

Onewasp,
Thanks for the information. Since I had been reading about reflexing, I did understand your comments.
My Spektrum DX6i only has two settings for the flaperons. So I will program switch one at zero and add 15% on flaps down to see what happens. Then, keep making changes until I get desired results.
I'm always trying different things, so this will be fun.

Again, thanks for taking the time with the comments.
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Old 01-12-2009, 09:39 AM
  #71
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Default RE: E Flite Eratix 3D 25e ARF Owners Club

I haven't received the plane yet, so I am just guessing about where to reinforce the airframe to withstand the vibrations generated by the OS 46.

And yes, I'll post some pictures.
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Old 01-15-2009, 01:41 PM
  #72
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Default RE: E Flite Eratix 3D 25e ARF Owners Club

Woodie - I ran the Eratix in my garage last night using two props not included in the factory specs. The battery was a 4S TP 3850 V2, the motor is a Scorpion 3020-12, ESC is a Mystery 80A, and here are the results:

11x7E (electristar prop) - Voltage before/min, amps, watts - 16.5/11.9, 70A, 832 watts
11x6E Master Airscrew - 16.3/12.3, 66.3A, 821 watts


Both of these exceed the motor spec on current (57A max), and wattage (800 Watts). I may run with the 11x6, but will probably go a get a couple of 11x5.5E props, which the manufacturer says gives 54.5A, 103 ounces of thrust and 762.6 watts, i.e. over 193 watts/pound at AUW 63 ounces, and stays within motor specs. I am a bit surprised at the relatively small props required to get these power figures. I guess it's the 1088kv as opposed to the 770kv for a Power 32.

I guess an alternative might be to run a 3S and 13x8E, which supposedly gives about 600 watts at 57A, and a weight saving of perhaps 4 ounces, i.e. 162 watts/pounds, but then I would have a CG problem.

The Scorpion motor weighs in at 5.5 ounces, as opposed to 8.6 ounces for a Power 32. The other new motor I want to try is a Turnigy SK 35-48 at 6 ounces, 900kv, which purports to handle 840 watts, with a maximum current of 60A. I was thinking of putting that one into an Extreme Flight 47" YAK that is waiting to be built.

Any thoughts relating to this stuff?

Regards...Chris
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Old 02-23-2009, 11:38 PM
  #73
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Default RE: E Flite Eratix 3D 25e ARF Owners Club

Well, my Eratix has managed a few flights in between the dismal weather. I managed to bend the gear once on landing, but no damage, perhaps because I had reinforced the gear mounting area with chewing gum and lettuce leaves (I mean epoxy and thin plywood.)

I love this plane! It seems to hang around lazily in the air, giving me the risky impression that I can actually fly it. The Scorpion 3020 with a 4S and 11x5.5E prop yanks it vertically into the sky and seems to suck down less than 250mah per minute given my (so far) careful flying. I guess that will be more like 300mah/min when I get more into it, so I should get a good 10+ minutes out of a 3700mah 4S battery. I may switch to an 11x7E prop just to push my luck pointlessly. Why not.
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Old 02-24-2009, 12:57 AM
  #74
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Default RE: E Flite Eratix 3D 25e ARF Owners Club

The Eratix is one of my favorites to fly. Like you said it seems to almost fly itself. Very easy to land and performs so many maneuvers making me look good. I will admit it’s the plane and a little bit of pilot I normally fly mine with 2x2200 3S in parallel and when I feel like I need more power I throw a 4S 3200 in and fly it like a maniac.
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Old 02-24-2009, 01:02 AM
  #75
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Default RE: E Flite Eratix 3D 25e ARF Owners Club

What motor and prop are you using with the 3S batteries?
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