Espritmodel.com Telemetry Radio
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Old Apr 17, 2007, 03:29 PM
registered foam addict
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Munich, Bavaria
Joined Dec 2004
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I believ the wood dowels are about 4-5cm long.
correct, the motor shaft is approximately aligned with the horizontal stab.
however, I can still tilt the motor a few degrees up and down so i can fine adjust the thrust line. thrust line ideally goes through the centre of gravity and centre of drag of the airplane. this is needed to eliminate pitch moments when you vary thrust during flight.
in other words, if the aircraft noses up at the moment when you give full throttle, the motor has to be tilted more downward (and vice versa).
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Old Apr 22, 2007, 09:15 PM
disciple
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United States, CA, Citrus Heights
Joined Jun 2005
172 Posts
Ace Bipie

Chara, I just couldn't resist. I am almost done with the airframe. I put a "snoopy" pilot in it too. The one where he is in a dog fight. Figured the Bipie might be better against the Red Baron than a Sopwith. I will repost when it is done. I haven't been able to fly the micro harpy so I have been building. The wind will stop some day. I have the left and right jpg files for the snoopy if anyone is interested.
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Old Apr 23, 2007, 04:41 PM
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Munich, Bavaria
Joined Dec 2004
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Hey disciple!
this looks just great! I think mine needs definitely a good pilot too ! So if you don't mind posting the Snoopy jpgs ... I would be interested!
Hope you make good progress and have a great maiden flight soon!
-chara

BTW: if you stay with single ailerons, roll rate might be a bit lousy. she rolls OK on rudder too but I prefer the ailerons. In case you want more roll rate, try out the 4-ailerons mod.
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Last edited by chara; Apr 23, 2007 at 04:49 PM.
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Old Apr 23, 2007, 11:54 PM
disciple
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United States, CA, Citrus Heights
Joined Jun 2005
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snoopy jpgs

Here are the snoopy jpgs. You just need to trim to fit. I printed these by trial and error to get the right size. The files aren't exactly the same size.
I flew the bumble harpy today, it is fast. Too fast for the park so I will try again at work where I have a larger field.
I have a Park 1360kv out runner with an APC8x3.8 and 3s 730mah TP for the Bipie. I also have a cdrom motor that needs rewinding. I am putting wheels and pants on as well for looks and ROG. I am going to attach the pants with wheel collars glued to them and then sliding them on the axle. Might work. Pictures soon I hope. Just need more time!
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Old Apr 24, 2007, 12:32 AM
disciple
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United States, CA, Citrus Heights
Joined Jun 2005
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New pictures

Duh, I figured all I needed was to copy and flip the image to make them the exact same size.... here you go....sometimes I try to make thing way too complicated...
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Old Apr 25, 2007, 03:10 PM
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Munich, Bavaria
Joined Dec 2004
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disciple, thanks for the pics!
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Old May 21, 2007, 01:41 PM
disciple
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United States, CA, Citrus Heights
Joined Jun 2005
172 Posts
Been dragging my feet

Well I lost my bumble Harpy in the local park in a very tall plane eating OAK tree (~70 feet up).
I have worked on my Bipie some but I still need to mount the servos and linkages. ESC and RX and motor are already mounted. I also have the landing gear and wheel pants on. I will post a picture tonight. Very windy today so no flying.
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Last edited by disciple; May 21, 2007 at 08:53 PM. Reason: spelling!
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Old May 21, 2007, 08:52 PM
disciple
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United States, CA, Citrus Heights
Joined Jun 2005
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Latest picture of my Bipie

Here is the pic of where I am with this. Maybe this will inspire me to finish it, when I see that it wouldn't take much to make it fly!
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Old May 21, 2007, 10:30 PM
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Daytona Beach!
Joined Apr 2007
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awsome looking BIPIE! cool color scheme 2
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Old May 21, 2007, 10:52 PM
disciple
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United States, CA, Citrus Heights
Joined Jun 2005
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Thanks foamasticflyer!

Appreciate the comment. I liked the original Pitts scheme that Chara used so I made a similar one. The stripes on the wing are more narrow. And I just realized I never showed the wing so here is the top view. I used blucor so it took more paint to cover, hence more weight. I used a gray primer then orange water based spray. Depron would cover without the primer.
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Old May 24, 2007, 01:47 PM
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Munich, Bavaria
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disciple, this looks preety cool - especially with the wheels and pants.
hope you will have a great maiden flight!
greets, chara
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Old May 29, 2007, 02:20 PM
disciple
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United States, CA, Citrus Heights
Joined Jun 2005
172 Posts
Wow!

This thing really moves! After my initial 3 second flight with the ailerons reversed I flew it for about 2 minutes (on ~1/2 throttle) in a steady 5(?) mph wind. When I took off it went up at a 45 degree angle with no trouble. I think it might do 3d if I put the rudder servo on it and take off the wheels. It was very fast and I was flying off a soccer feild. When I landed one of the cheesy wheels broke at the axle where I had drilled it out to fit the heavier wire (.062). The .047 wire drooped when I put the battery on it so I rebuilt the landing gear before the maiden.
I need to put a bigger prop, 9x3.8, and run on 2 cells for awhile to get familiar with this. It is really responsive. I will put some old dubro 2" wheels that I have had laying around on it. They will be good for any field and will add some low center weight to stablize thing while I gain some stick time. Chara, I can see why you left off the wheels. A hand launch would be no problemo with this. I just like the looks better. The AUW was ~11ozs with 3S 730 Thunder pro lite, 8x3.8 prop and a park 370 1360kv outrunner. Way enough power for full aerobatics. Pulls 8.5 amps so it is around 85-90 watts. My son flew his slow stick for awhile and did great even in the wind so it was a great Memorial day. Video next time.
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Old May 30, 2007, 01:24 PM
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Munich, Bavaria
Joined Dec 2004
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disciple, great! congrats for the successful maiden flight. I'm glad you are happy with your Bipie. do you have 4 or 2 ailerons on yours (pictures look like upper wing has no ailerons). I found mine a bit to sluggish with 2 ailerons only.
but it could be an effect of my undercambered wings...
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Old May 30, 2007, 01:59 PM
disciple
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United States, CA, Citrus Heights
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Ailerons

Chara, I have the lower only ailerons. It seems to have plenty of control but I am using dual rates and I am at 35% right now. Also I think I am right on the edge of the COG so it might be a bit tail heavy and thus sensitive to control. I am going to get some altitude and try full control hopefully on the next flight to see what the roll rate looks like. I didn't do anything fancy on the first flight. I do think the flat wings make the ailerons more resonsive but only testing will verify. The heavier wheels will dampen the role rate some. I will go to LHS and look for lighter big foam wheel maybe today. These are old dubro wheel from a nitro plane. 1.5 oz per pair (HEAVY ). my AUW is still only 12.5 ozs so I think it will still have some ZIP.
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Old May 30, 2007, 08:50 PM
disciple
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United States, CA, Citrus Heights
Joined Jun 2005
172 Posts
Good flight

Well the bipie flew again and it was very stable except for slow landings. I think the heavy wheels made the COG to low so it took more control input when I slowed it down. Also the battery I used wasn't up to the amp draw. I bought some foam wheels and some connectors so I can use my Kokam 2S 1500 pack. The AUW is still 12.5oz's but the COG is centered more so I think it will handle better at slow speed. I will add a bit more throw for good measure. It looks great when it is flying. A friend at work that use to fly RC years ago commented on how good the design looked. Of course most people like the snoopy pilot. The flight was shorts again but I am fine tuning it. I think tomorrow I will be able to try a loop or two. Did one role today but the wheels and maybe the single wing ailerons with the dual rates at 35% made it kinda slow. I wil try to take a picture tonight of the new wheels etc...
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Last edited by disciple; May 30, 2007 at 11:23 PM. Reason: Add picture
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