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Old Jul 10, 2011, 05:06 PM
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Bedford, Mass. USA
Joined Dec 2007
386 Posts
Nice post. Glad they were able to catch you and tell the world about combat wings... and get a plug in for Crashtesthobby. I get stopped a lot myself when I pull over and throw it up, but not by a newspaper!
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Old Jul 10, 2011, 06:09 PM
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Bombay's Avatar
Richmond, TX
Joined Apr 2008
3,236 Posts
Quote:
Originally Posted by mdmowrey View Post
I just got the LEDs installed Friday night and had my first ever night flight Saturday night. The LEDs are super bright and light the wing up well. I can't see the design in flight so it is difficult to tell top from bottom.
MD:
So the fact that the green is on the right and white on the left doesn't help you determine top from bottom?

I haven't flown a wing yet where the leds show thru the top and bottom...I've only flown them where the leds are one color on top and a different color on bottom...but it would seem that having one half one color and the other half another color would aid in orientation.
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Old Jul 10, 2011, 07:54 PM
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United States, OH, Urbana
Joined May 2010
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Quote:
Originally Posted by Bombay View Post
MD:
So the fact that the green is on the right and white on the left doesn't help you determine top from bottom?
It helps my mind dermine left from right. If the wing is in such a position that I can see the distinct "V" pattern it makes sense to me but in a position where the pattern is more of a line, my mind doesn't have enough experience to quickly determine upright going away vs. inverted coming towards... yet. Like I said, it was my first night flight ever.

One idea I had was to clip one segment of the LEDs off the strip and re-attach it with the diodes facing out of the foam. That should help with top/bottom orientation.
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Old Jul 10, 2011, 09:07 PM
Planes in flames,,,
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Gravity Sucks
Joined Aug 2010
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Mark, on my big wing I have the LEDs facing up into the foam on the bottom side.
On the top side I have just a couple of strips that face outwards. they are indeed super bright and leave no doubt as to which side is up. The only caution is with lights on the top of the airfoil you need to take care you do not disturb the airflow over the top of the wing. Either arrange the light strip on the top to run front to back or make a trench for the lights to sit in so the surface is not disturbed. Night flying is awesome fun. Night combat is even more fun!

No matter how you have the wing set up, night flying (for me anyway) can be disorientating. I flew a week or so ago after not flying at night for a while and it took me a good little while to get back into the groove.
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Old Jul 10, 2011, 09:10 PM
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Richmond, TX
Joined Apr 2008
3,236 Posts
Quote:
If the wing is in such a position that I can see the distinct "V" pattern it makes sense to me but in a position where the pattern is more of a line, my mind doesn't have enough experience to quickly determine upright going away vs. inverted coming towards
MD:
I know what you mean. Sometimes your mind can 'misread' the shape of the V. One thing that helped me...which I learned from another flyer...was to put a small strip (3 leds) on the back of the wing. Believe it or not, that happened immensely.
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Old Jul 10, 2011, 09:14 PM
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Lee's Summit, MO USA
Joined Jan 2001
387 Posts
Quote:
Originally Posted by KC Flyer View Post
The MicroDan rewind works great with 9 turns - maybe a little too good!

With fully charged batteries, I got 14k rpm with the HK 7x6 prop. But also 33 amps out of my HK SS 25-30a ESC. After the batteries drained down a little was still getting 13,200 rpm at 10.6v.

Was really windy this morning but took it to the field anyway. Great unlimited vertical and really quick rolls. Motor was cool even after a spirited run. Flight time shorter and ESC/battery a little warmer than usual.

I did notice that the motor stuttered at 11,500 rpm with prop on but not at any other speeds. Prop was balanced so I tried a different rotor (bell) and bearings but same problem. Then I changed the timing from medium to high and the problem went away.

Here are a few performance numbers below with HK 7x6 prop (the Kv values were calculated by putting 2 pieces of electrical tape on the rotor with no prop, then taching and dividing by voltage):

Stock: 1480 Kv, 11,400 rpm @ 11.2v & 16a
RS 26ga/10T: 1780 Kv, 12,400 rpm @ 11.2v & 21a
MD 24ga/9T: 1975 Kv, 13,200 rpm @ 10.6v & 27a

Here are a couple pics. The first is the stator with burned out RS 26 ga wire. The second is the same stator with MD 24 ga wire. It was hard to fit 9 turns on it. On the third tooth (out of 4) on each piece of wire, I used 8.5 turns which I later learned is equal to only 8 turns (only a full turn counts).

If you want to rewind a stator with 10 turns, I would use MD 25 ga wire to fit it all in and do 10.5 turns on the 3rd tooth. This should last much longer than 26 ga Radio Shack wire.

I finally got around to measuing data from this rewound motor. First chart is the RPM vs Watt graph. Next is a pic of my setup to measure static thrust, RPM, Watts. This is my first attempt in doing something like this. I also added my spreadsheet in case anyone is interested in more detail (or wants to add efficiency, etc.)

Basically, I love the results of the rewind. As you can see from the chart, I really don't lose much efficiency over the range of the stock motor - but I can cram twice as much power through the rewound motor if I want.

The motor did get a little warm during testing. In flight it stays pretty cool due to the fully exposed install on the Assassin.

Weight of motor/mount/power connector is 43.0 g stock and 44.0 g rewound.

I started another thread on this motor and its rewind potential:
http://www.rcgroups.com/forums/showthread.php?t=1456812
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Old Jul 10, 2011, 10:21 PM
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Lee's Summit, MO USA
Joined Jan 2001
387 Posts
Here's a graph showing thrust of stock vs. rewound motor:
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Old Jul 10, 2011, 11:44 PM
Planes in flames,,,
jetpackninja's Avatar
Gravity Sucks
Joined Aug 2010
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So KC Nice research!
So if I understand what your numbers and research suggests:
10 winds will give a good improvement over the stock wind on the little red motors.
9 winds will give a great power improvement but will come at a cost of running a much higher wattage setup and likely not last nearly as long?

I have two red motors that need rewinding, just haven't got around to trying it yet
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Old Jul 11, 2011, 12:10 AM
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Renton, WA
Joined Oct 2005
57 Posts
DX6i Radio Problems

Hi Lee,

After about 1 year of use, my DX6i transmitter that I use with my Roswell appears to be failing - up/down elevon does not work, but left and right elevon does work - Caught this in my pre-flight check. I swapped out the Spectrum AR6110 receiver for an Orange 6 channel Rx, bound it, and had the same result. So I assume that the transmitter has a fault and I should send it in for servicing.

I got out my brand new DX6i Tx, programed for elevon and bound it to the same AR6110 receiver. The servo directions are correct, but the left servo provides about 1/4" more left elevon up deflection, and the right servo provides about 1/8" more right elevon down delflection. I double checked that the servo arms are both two teeth up from neutral, the pushrod is in the outer hole on both arms, and in the upper elevon control horns. We re-set the trims and the control surface EZ connectors to ensure all was correct. Could one of the servos be failing? If so, how would I know which one is going bad?

I don't want to fly until I resolve the imbalance.

Do you have any suggestions?
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Old Jul 11, 2011, 07:19 AM
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Lee's Summit, MO USA
Joined Jan 2001
387 Posts
Quote:
Originally Posted by jetpackninja View Post
So KC Nice research!
So if I understand what your numbers and research suggests:
10 winds will give a good improvement over the stock wind on the little red motors.
9 winds will give a great power improvement but will come at a cost of running a much higher wattage setup and likely not last nearly as long?

I have two red motors that need rewinding, just haven't got around to trying it yet
10 winds is probably a good compromise but I wouldn't use Radio Crap wire. I would use MicroDan 25 or 26 ga as it will handle the heat much better.

I like the 9 winds best as I have power to spare and don't have to use it if I don't need it. I have no reason to believe that the motor will not last as long using the MD 24 ga wire. My guess is that the 25-30a ESC might fry one of these days - but probably not the motor.

As I learned later, the video does 10 & 9.5 winds which is not optimum. 10 & 10.5 or 9 & 9.5 winds is what you want to use as a half wind doesn't count
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Old Jul 11, 2011, 03:00 PM
Life is better, when you fly.
United States, CO, Conifer
Joined Oct 2006
128 Posts
I have 2 newly built Assassins. However, I just miss the loud angry screaming of my old Wing Warrior eRaider. So I thought I could keep my stock bullet proof Assassin, and make the 2nd a faster, louder, heavier, though surely less nimble, Assassin.

I was thinking to match a 4 gram 3200KV inrunner with 2200 3S Turnigy nano-tech, and a 5x5 prop. It seems like the CG balance might be close enough to work. I have a 40A and 60A ESC if I need to use that too.

1) has anyone had good results like this?
2) how do you mount the motor? It won't fit on top of the plane, behind the motor mount. Maybe if I bend the motor mount out, so the prop has a slight down focus, and give the elevons a higher start for more lift? That seems to be how my eRaider is setup.

Eric
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Old Jul 11, 2011, 03:05 PM
Life is better, when you fly.
United States, CO, Conifer
Joined Oct 2006
128 Posts
On another note, how long is the average build time on these Assassins? My fly buddies and I are averaging 11 hours per plane, including soldering.

To be fair, we are extra anal retentive about the process. On top of that I sometimes think we are a drinking club with an airplane problem. Maybe that's where the time goes?

Eric
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Old Jul 11, 2011, 03:48 PM
Combat: You're doing it wrong.
chewbaccah's Avatar
United States, UT, Layton
Joined Sep 2009
1,807 Posts
Quote:
Originally Posted by Docta View Post
I have 2 newly built Assassins. However, I just miss the loud angry screaming of my old Wing Warrior eRaider. So I thought I could keep my stock bullet proof Assassin, and make the 2nd a faster, louder, heavier, though surely less nimble, Assassin.

I was thinking to match a 4 gram 3200KV inrunner with 2200 3S Turnigy nano-tech, and a 5x5 prop. It seems like the CG balance might be close enough to work. I have a 40A and 60A ESC if I need to use that too.

1) has anyone had good results like this?
2) how do you mount the motor? It won't fit on top of the plane, behind the motor mount. Maybe if I bend the motor mount out, so the prop has a slight down focus, and give the elevons a higher start for more lift? That seems to be how my eRaider is setup.

Eric
This setup sounds a little heavy for an assassin. Will it fly? Yes, like a rocket.... Will it glide? Like a rock . I like the setup Lee recommends. It is inexpensive, powerful, rugged and light. I rewound the motor he suggests (after frying it) and now it has even more power and top speed. You can't mess with perfection.

On the otherhand, head-to-head mid-air crashes with two assassins at 100+ mph makes for a good summertime popcorn spectater sport.
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Old Jul 11, 2011, 10:17 PM
Life is better, when you fly.
United States, CO, Conifer
Joined Oct 2006
128 Posts
Ya, I'm very impressed with my stock Assassin. I do want to do any experiments with it.

With my 2nd Assassin, I figure if I don't like it, I can always put a little red CF2812 motor back on it. Do you think it will a big problem if I have to bend the metal motor mount away from the plane to make the inrunner sit behind it flush with the trailing edge of the wing? The only other option is to find a taller motor mount or try some variation of the velrco motor mount.
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Old Jul 12, 2011, 01:15 PM
Combat: You're doing it wrong.
chewbaccah's Avatar
United States, UT, Layton
Joined Sep 2009
1,807 Posts
Quote:
Originally Posted by Docta View Post
Ya, I'm very impressed with my stock Assassin. I do want to do any experiments with it.

With my 2nd Assassin, I figure if I don't like it, I can always put a little red CF2812 motor back on it. Do you think it will a big problem if I have to bend the metal motor mount away from the plane to make the inrunner sit behind it flush with the trailing edge of the wing? The only other option is to find a taller motor mount or try some variation of the velrco motor mount.
As long as the bend does not cause a thrust angle problem, or make it tail heavy. Instead of bending the mount, can you move it back further?
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