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Jan 25, 2008, 09:02 AM
rab
rab
Grounded in Arlington
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The paint and stickers added just over three tenths of an ounce.

I've been thinking about the fan. I was trying to use a 5kcv motor on 2s, I am going to try a 4kcv motor on 3s next.

I also suspect that I made a mistake in my duct work. I'll be setting up a ductwork test bed.

- Allen
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Jan 25, 2008, 07:04 PM
space1
thats better man you got to put some juice in edf try 4s two 2s in ser
Jan 26, 2008, 02:37 PM
rab
rab
Grounded in Arlington
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Yeah, well for the performance I would like I think I should be aimed at a 4000kv motor on 3s or a 6000kv motor on 2s. They would each spin the fan about the same rpm and the each power system combination comes out about the same weight.

The 5000kv motor I was trying to use, needed a battery that was too heavy on 3s and on 2s it just did not spin fast enough.

- Allen
Jan 26, 2008, 03:05 PM
space1
i use hyperflow 55mm 13.5 oz thrust 3s 1300ma 2s 7.6 oz most 10.7
Oct 26, 2008, 04:04 PM
rab
rab
Grounded in Arlington
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I have refactored this effort. So far the results are very encouraging. I successful test flight of a close to complete model this morning.

As I suggested above I acquired a Hyperion P1913 6 turn 2.3 mm 4 magnet to use with the GWS 55 fan. I built the ducting and fuse with 3mm Depron and the wings with 1/4in blue FFF. I am getting around 15oz static trust out of the fan with ducting.

The airframe grew a little more than 15%. The weight as flown today was 16.5 ounces, so the wing loading is less than the first one.

- Allen
Oct 26, 2008, 08:54 PM
rab
rab
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Here are a couple of images from the construction of this instance.

Now that it has flown I will finish the body work and paint it. I did not stress about the nose cone shape since I did not expect it to survive the first flight, but it did. So the nose will get replaced, I'll add a canopy, dorsal hump, and the exaust area. I am expecting all that to add about an ounce.

Here is the link to the test flight.

- Allen
Last edited by rab; Oct 26, 2008 at 09:41 PM. Reason: link to video thread
Oct 27, 2008, 05:36 AM
I'm not flying backwards!
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Rab, nice design and build.

Tony
Oct 27, 2008, 07:07 AM
Registered User
Wow! Allen,

I just saw this build, very cool. Looks like it's pretty fast. My guess is it rolls like a MiG-21, like a dart.

Great job.

Pete
Oct 27, 2008, 07:58 AM
rab
rab
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Thanks Tony. This one has come out a bit pudgy looking, I don't think I made the best compromises for the non-scale intakes. Now that I have one that works the next time I will adjust the dimensions to be a bit more scale.

Thanks Pete. Yes, the speed is about right for a park jet. And yes the roll rate is like a drill. I programed dual rates and a lot of exponential on the ailerons so most of the time it is manageable. This one is much nicer to fly than the first one. In a few weeks when the details are done this one should look better.

- Allen
Oct 29, 2008, 10:55 PM
Lori, hey, you're home early
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Allen-- Very nice. I just watched the video and it flies great. I've been slowly working on one for EDF 55 too.

Mike
Oct 29, 2008, 11:42 PM
Lori, hey, you're home early
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Allen-- What's the wingspan now? I scanned through the thread but didn't see it. I fly my 12.7oz Freewing F-35a 23.2" span on the GWS EDF55 and a Feigao 4500kv (I think) on 3s 1000 lipo. I'm thinking of resizing my Viggen to something like 22" or 23" from the current 17.5".

Mike
Oct 30, 2008, 09:57 AM
rab
rab
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The first one has a 20 inch wingspan and was most all quarter inch FFF. This one has a 24 inch wingspan and is a mix of quarter inch FFF and 3mm depron, the colors in the photos should show what is what.

I had to revise my ducting twice to keep my amp draw reasonable. That is the part I built first. Tested it on the trust stand with a watt meter to insure I did not repeat my earlier errors.

The size was chosen as a compromise between available thrust, wing loading, and the size of the inlets. Using the very technical 'that seems about right' method.

- Allen
Oct 30, 2008, 10:17 AM
Lori, hey, you're home early
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Quote:
Originally Posted by rab
...The size was chosen as a compromise between available thrust, wing loading, and the size of the inlets. Using the very technical 'that seems about right' method.

- Allen
That method works well most of the time. Commonly called "TLAR" or "That Looks About Right".

TLAR for me will be a 23" or 24" span. I use a tile printing program and it's a pain to get an exact span dimension.

I'm going to order a Wemo Microfan for it though since I realized that I have an HET 240-15 motor going spare at the moment and it makes nice thrust on 3s (13 to 15oz static I believe). If it turns out too heavy for the Micro fan's thrust at 24" span it'll be big enouch to possibly squeeze in a 70mm fan I think.

Flew very well in the video. Seemed very nice with no bad habits. Going with the blue and yellow paint?

I really like the Viggen. If I could only have a few EDF's they'd be the Viggen, the F-104 and the Gripen. My 3 favorites.

Mike
Nov 15, 2008, 06:21 PM
rab
rab
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Made some progress revising the details. The appearance is rather cartoon scale. I am now trying to decide what to paint it. I am debating between

1 an imitation of the fields and meadows camouflage color scheme.
2 blue and yellow with orange numbers
3 or a chevroned camouflage in the fields and meadows colors.

Here are a few images to illustrate.

- Allen
Nov 30, 2008, 10:54 PM
rab
rab
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I've flown it a few more times. I'm very happy with it's performance. Good maneuverability and adequate speed. I was wondering how fast it would feel at a big field; I was concerned that it would seem to take too long to traverse the field. But it was fast enough for me.

The combination of the GWS 55 and the Hyperion HP-P1913M-06 motor is working well for me in this airframe.

I've gone with painting option 1 and am perhaps two thirds done painting the plane. After I finish painting I don't think I will be able to see this one in the twilight.

Mike, I find that I am fascinated with canards, the Viggen being my favorite.

- Allen


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