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Old Feb 22, 2013, 06:24 AM
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United States, FL, Palm Beach
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36-40" fits in a hatchback sideways easily and launches with a flick of the wrist. The Swift is 32" I believe, and handles all fpv gear and a gopro, but just barely. It also maintains slow speed flight and stability with that load on board. A few more inches of wing area, thanks to a custom cut blunt center section, and it will handle dual batteries for longer flights as well. But there are still supply problems with that model. I also feel 60+s&h without laminate is steep. CTH seems to have good supply and kit pricing, but nothing for mid size wing fpv. I've been flying a Multiplex EasyStar fpv and I'm sick of field assembly every time I want to fly. So I'm moving to all wings. Battery, check surfaces, toss!
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Old Feb 22, 2013, 10:55 AM
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United States, MD, Kensington
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Originally Posted by viper522 View Post
Battery, check surfaces, toss!
You actually check surfaces before toss?
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Old Feb 22, 2013, 11:35 AM
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United States, CA, Livermore
Joined Jan 2012
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changing prop causes big trim change?

Yesterday, I flew with the usual 7x6 APC prop. Today I tried an 8x4 GWS which I have measured to draw a little less power. However, after changing the prop, the trim was way off. I guess i don't understand the aerodynamics enough to know if this makes sense or not. It seemed to need a lot more down trim and a lot more right trim.

If the larger diameter prop generates more torque, I guess I can see why I needed more right trim. I did notice on the 7x6 that the amount of right trim varied with power. I needed more right at full power than at half power.

I don't see though why I would need more down and its not obvious that an 8x4 generates more torque than a 7x6.
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Old Feb 22, 2013, 11:57 AM
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United States, CA, San Diego
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Originally Posted by rhodesengr View Post
Yesterday, I flew with the usual 7x6 APC prop. Today I tried an 8x4 GWS which I have measured to draw a little less power. However, after changing the prop, the trim was way off. I guess i don't understand the aerodynamics enough to know if this makes sense or not. It seemed to need a lot more down trim and a lot more right trim.

If the larger diameter prop generates more torque, I guess I can see why I needed more right trim. I did notice on the 7x6 that the amount of right trim varied with power. I needed more right at full power than at half power.

I don't see though why I would need more down and its not obvious that an 8x4 generates more torque than a 7x6.
Power/Torque might be getting confused with the effects of airspeed. Throttling up and gaining airspeed can accentuate any trim issue. A warped aileron or imperfection in the airfoil can cause trim issues that are only amplified with speed.

Assuming you are using the CF2812 motor, there is nearly no noticeable torque on the Assassin or Widowmaker with a 7x6. The effects of torque are felt at low speed, you should not feel them at all once at speed with the recommended power setup.

I've built nearly 10 Assassins for myself and others, with power setups from 2s-4s, 150w to 650w+ and torque really isn't a huge issue with these wings at these power levels.

Take a look at your elevon surfaces and wing halves to ensure there is no warping or twisting. Check your control horns and clevices to ensure there is no play or wiggle room.
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Old Feb 23, 2013, 01:49 PM
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Originally Posted by nofreee View Post
Power/Torque might be getting confused with the effects of airspeed. Throttling up and gaining airspeed can accentuate any trim issue. A warped aileron or imperfection in the airfoil can cause trim issues that are only amplified with speed.

Assuming you are using the CF2812 motor, there is nearly no noticeable torque on the Assassin or Widowmaker with a 7x6. The effects of torque are felt at low speed, you should not feel them at all once at speed with the recommended power setup.

I've built nearly 10 Assassins for myself and others, with power setups from 2s-4s, 150w to 650w+ and torque really isn't a huge issue with these wings at these power levels.

Take a look at your elevon surfaces and wing halves to ensure there is no warping or twisting. Check your control horns and clevices to ensure there is no play or wiggle room.
Well I appreciated your experience but it felt like and looked like torque problem. Bad lanches always went left and more power in the air caused more roll to the right.

So I tried an experiment. An easy way to add a balancing torque (when the wing is flat to the ground) is to add a weight on the right wing tip. I popped on a 7g weight out there. This and dropping to about 75% power at launch gave me to straightest lauch yet. So it seemed to help. This also adds moment of interia to it is harder to acclerate in the left roll direction. Once in the air, I didn't notice it.
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Old Feb 24, 2013, 08:03 AM
Lee
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If you are having launching problems, launch from the center of the plane with a brisk toss and power up after the plane is our of your hand. See Mikes toss at about 1:25 on this video vs the launch I did at the first of the video. Just be careful not to get your hand in the prop with the power on.

You can build ultra light with our planes too. I am building a Deep Reaper without the extension, that won't be laminated, and hope for a total weight of under 25 oz. How you build is up to you. How light you want to build is an important decision. I am using the Shock Cord. I will be using paint for color. The plane will be so light I hope to use a nose mounted 2812 motor and use the plane for super slow park flying.

Deep Reaper 2-13 (2 min 53 sec)
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Old Feb 24, 2013, 09:11 AM
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I was pounding the ground about every 3 to 4 Assassin launches for weekend after weekend. Used nose and wing launch styles and still I would dork it in way too often. Then instead of hard tossing I just started gently tossing at 1/2 throttle by the wing end and discovered Assassin launch happiness. Now the drama is gone and my Assassin is much better for it!

Blu
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Old Feb 24, 2013, 11:08 AM
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I was pounding the ground about every 3 to 4 Assassin launches for weekend after weekend. Used nose and wing launch styles and still I would dork it in way too often. Then instead of hard tossing I just started gently tossing at 1/2 throttle by the wing end and discovered Assassin launch happiness. Now the drama is gone and my Assassin is much better for it!

Blu
Absolutely, as long as the assassin is within the recommended auw, 1/2 throttle and a toss like you're throwing a shirt on the bed, with a little up trim and you're golden. Don't use a lot of wrist, just the arm motion like you're trying to guide it onto a cushion of air. The plane will do the rest!
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Old Feb 24, 2013, 12:48 PM
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United States, FL, North Fort Myers
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Originally Posted by viper522 View Post
Absolutely, as long as the assassin is within the recommended auw, 1/2 throttle and a toss like you're throwing a shirt on the bed, with a little up trim and you're golden. Don't use a lot of wrist, just the arm motion like you're trying to guide it onto a cushion of air. The plane will do the rest!
+1 DJ
I think that's a very apt description viper. When I first got my assassin together I took it out in the open flat field, no trees, no polls just grass and started slinging this thing. Role left crash, role left and crash etc. etc. etc. then I started noticing something, being right-handed when I held the front edge of the end of the wing with my right hand, forefingers on top, and, thumb underneath that on launch I was actually holding the wing down when the plane tried to rise.

So I tried something new I let the wing tip that I wasn't holding sit on the ground a little behind me, I would push up the throttle until the plane started the pull then I would let off the gas. I tried to develop a little rhythm of throttle up, plane pulls, let backoff to get some smooth timing happening all the time keeping in mind that I wanted to lift the wing with my thumb as I released it.

Long story short; I finally had my head in the right place. I struck the pose, came in on the throttle, plane started pull, push the throttle up to about half the plane tried to fly I simply extended my arm is plane left the ground flipped up with my hand at release. The plane flew out dead level again and again and again.

Like all planes it will want to roll to the left due to P-factor and torque. Flipping the wing up slightly helps that a lot plus the outside wing will naturally want to rise and if you hold the launch wing down you've already turned the plane to the left.

I had so much fun I started trying to see how slow I could launch it it's amazing! Tried to flip the wing up hard on launch to see if I could get it to roll right, found it doesn't want to roll right and I'm not going to be able to flip it right make it crash found that really interesting.

Now I've taught my flight instructor and a couple other guys at the field how to do this and they all are doing it well.

It is; do not throw the plane into the air. Lay the plane on the air and it will fly away.

DJ
BTW: being able to show my instructor something and teach them how to do it was so gratifying.
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Old Feb 24, 2013, 01:32 PM
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Lay it on the air cushion (first few secs)

CTH Assassin 34" flying wing - 2 (6 min 16 sec)
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Old Feb 24, 2013, 06:37 PM
Dixie Sky Devils AMA# 1015548
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United States, MS, Tupelo
Joined Oct 2012
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Had flying weather today! can you believe it!! actually got my 3rd flight with my Assassin, first wing ever for me!


http://www.youtube.com/watch?feature...i0F-UFiUk#t=1s
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Old Feb 24, 2013, 06:52 PM
Lee
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Love the videos. I just uploaded a video shot by Mike and James from last fall at the local 2012 sWARm also known as the UnCivil War 2012. I thought it was about time.....

UnCivil War Fall 2012 (7 min 12 sec)
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Old Feb 24, 2013, 08:13 PM
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Quote:
Originally Posted by Bluhammer View Post
I was pounding the ground about every 3 to 4 Assassin launches for weekend after weekend. Used nose and wing launch styles and still I would dork it in way too often. Then instead of hard tossing I just started gently tossing at 1/2 throttle by the wing end and discovered Assassin launch happiness. Now the drama is gone and my Assassin is much better for it!

Blu
You got that down now bro.
Now its my turn to learn.
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Old Feb 24, 2013, 08:23 PM
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Here it is my new Assassin fresh off of the bench this morning.
Many thanks to Dave (Blu) and to Jim for all of the build help and support.
Thanks to Dave for all his help today with setting it up today and with the Maiden Flight
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Old Feb 24, 2013, 09:07 PM
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United States, FL, North Fort Myers
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Originally Posted by foamyflyerr View Post
Here it is my new Assassin fresh off of the bench this morning.
Many thanks to Dave (Blu) and to Jim for all of the build help and support.
Thanks to Dave for all his help today with setting it up today and with the Maiden Flight
Flyer, that's a nice looking airplane. Not only did you give great contrast in what is the top and what is the bottom you did it artistically.

DJ "half the fun of going is looking good getting there"
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