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Old Jun 14, 2011, 05:40 AM
ExPat
Aero Andy's Avatar
Spain, Murcia, Mazarrón
Joined Apr 2010
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Stunning looking bipe, great job on the build, well done
Andy
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Old Jun 14, 2011, 01:36 PM
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Very nice!
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Old Jun 14, 2011, 10:34 PM
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Malaysia, Selangor, Kajang
Joined Jun 2009
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Built the motor mount this morning. How you mount your motor is really up to you. You may use a firewall if you like. I'll include an optional firewall in the plans later. The floor of the battery bay is also perfect for a stick mount. That's why it is positioned a bit lower than center line.

I use a slightly less conventional firewall-on-a-stick. Sort of like what you see on some pusher jets. The reason for this is that I don't have any screws small enough to mount the motor I want so I'm using twisted steel wire to mount the motor. A firewall would make installation awkward. My solution is to make the whole motor mount removable.
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Old Jun 16, 2011, 11:41 AM
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Malaysia, Selangor, Kajang
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OK, got a lot done since the last update. Installed the control rods for the elevator and rudder, built the wing mount and installed the aileron servos.

The wing mount took a bit of time mainly because I didn't think too much about it when drawing the plans. I thought I'd solve it as I build it. I considered a lot of ways to do it including using rubber bands but in the end settled on using a single screw to hold the wing in place.

I also had to rethink my original plans for the aileron servos. Originally I had planned on using a single HXT500 which is why the control horns were mounted underneath the ailerons. Looking around I realised I ran out of 5g servos so settled on using two 3g servos. Since I'm using two servos I decided to re-position the control horns above the ailerons. This allows me to belly land the plane if necessary.

Now that she's 99% done I decided to weigh her. Her AUW with a 370mAh battery is just a touch under 217g (7.7oz). With a 610mAh battery she weighs almost 227g (8oz). Since the motor produces roughly 230g of thrust this gives her slightly more than 1:1 thrust to weight ratio. I'm happy with that. I always have the option to upgrade to a 3s pack which should give me around 330g of thrust (so says Hobbyking).

CG check indicates that she is a bit tail heavy with the 370mAh pack but she should balance fine with the 610mAh pack.
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Last edited by slebetman; Jun 17, 2011 at 12:16 AM.
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Old Jun 16, 2011, 04:39 PM
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Joined Sep 2007
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Great build!!! Do you have any flying videos??
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Old Jun 16, 2011, 07:24 PM
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Malaysia, Selangor, Kajang
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Quote:
Originally Posted by DavidPORTUGAL View Post
Great build!!! Do you have any flying videos??
No, haven't maidened her yet. Will fly her on Saturday.
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Old Jun 16, 2011, 11:48 PM
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Malaysia, Selangor, Kajang
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Updated the plans. See first post.

I've re-arranged the pieces so that they print on 10 sheets of paper rather than 12. I've also made the plans available in both A4 and US Letter format.

Also, I've made a 'half' version of the plans for those who prefer to cut templates that way. The half version is better suited to a pure box build rather than a fold-over build.

The original artwork is in SVG (made with Inkscape). Is anyone interested in the original SVG for editing/mods in Illustrator or Inkscape?
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Old Jun 17, 2011, 12:15 AM
skumgummi dave
Gresham, OR.
Joined Mar 2004
1,959 Posts
Thank you for the plans. Very fine build. Will enjoy report on first flights...

Dave-
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Old Jun 17, 2011, 04:57 AM
It's Just Foam!!!
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Canton,Ga
Joined Apr 2010
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I'd love the svg's. Thanks. REALLY nice job on this plane!
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Old Jun 17, 2011, 07:41 AM
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Malaysia, Selangor, Kajang
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I'll maiden her tomorrow morning. In the mean time, here's a teaser:

Pitty Bipe taxi test 1 (0 min 24 sec)
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Old Jun 17, 2011, 08:16 AM
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Looking very good! Can´t wait to see the the maiden report.
I hope it will be easy to fly, i have poor flying skils... But on the other hand i m a master on repairs
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Old Jun 18, 2011, 06:27 AM
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Malaysia, Selangor, Kajang
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Well, crashed her on the first flight this morning. Didn't even get the chance to take some videos. She was a tad tail heavy as I sort of expected - just like her profile prototype. Was hoping that the adjustments I made to the plans was enough to correct that problem.

Tail heaviness in itself shouldn't have been too much of a problem because I got used to it when flying the prototype. But this morning was quite windy. Straight from take-off she climbed to vertical and a gust of wind flipped her over. Managed to recover but she by then she had drifted too close to the roof of a gazebo. Left wing clipped the roof and she spun all the way to the ground.

Damage was repairable with only a small increase in weight. It's still windy this afternoon so I'm planning on getting up really early tomorrow to fly her again.
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Old Jun 19, 2011, 09:03 AM
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Malaysia, Selangor, Kajang
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Finally managed to fly her this morning. First flew with a 610mAh pack to eliminate tail heaviness. Later with a tiny bit of elevator trim adjustment I even managed to get her flying with the 370mAh pack I originally planned.

Here's a video of the maiden flight (let's not count yesterday's crash as a "flight"). Sorry for the poor quality:

S6003646 (0 min 47 sec)


The good news is that she flies well as either a full 4 channel setup or with just rudder and elevator or even bank-and-yank aileron and elevator. With a rudder and elevator setup she's a very gentle flyer. Not quite trainer-like but very, very stable.
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Old Jun 20, 2011, 02:43 AM
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Nice job!!! I'm glad the bipe survived the crash. It looks like it has plenty of power. Were you able to test out its 3d capabilites?
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Old Jun 20, 2011, 11:24 AM
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Malaysia, Selangor, Kajang
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Quote:
Originally Posted by soulreaper View Post
Nice job!!! I'm glad the bipe survived the crash. It looks like it has plenty of power. Were you able to test out its 3d capabilites?
I'm not skilled enough to fly 3d. It does however loop nicely both inner and outer. For now, I've only installed control horns for the bottom ailerons so rolls are rather sluggish. Which is good for me because it allows me to practice with more precision. From experience with the prototype I've built before I can tell you that with all four ailerons she can roll really quickly.

With the 370mAh/25C battery it can do almost vertical climbs for the first 2 minutes or so of flight. After about 5 minutes loops becomes almost impossible. But with the 610mAh/20C battery she'll do loops until the battery runs out. I think the ideal battery for her would be around 600mAh 2S for 15 minutes of gentle, non-acrobatic flight and 500mAh 3S for 5 to 10 minutes of all out acrobatics.

I still want to test heavier batteries to see how much weight she can handle. It would be great if she can take 800mAh 2S or 600-700mAh 3S because she's really draggy and will gobble up milliamps if you want to do anything other than lazy circles.
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