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Old Aug 31, 2011, 02:31 PM
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Canada
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Thank you sir!


[/B]
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Originally Posted by MIT KID View Post
Now that I have it all together, I'll add all the servo/wire cutouts to my drawings and repost the plans.

-A
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Old Aug 31, 2011, 02:53 PM
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NYC
Joined Jun 2008
329 Posts
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Originally Posted by MIT KID View Post
Put together a 50% scale version of the Su-27 from rc.tomhe.net, for the innards of a crunched Beast.

I had to clip the prop by around 0.5in to fit into the slot, but it still has a bit over 1:1 thrust at 48g. Flies great with the tailerons and rudder.

-Adam
Great job Adam, any chance you have a video? Let me know if you plan to sell it
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Old Aug 31, 2011, 04:04 PM
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United States, IL, Washington
Joined Nov 2008
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Originally Posted by buratino View Post
Very nice plane, I wanted to build a similar plane with 1S setup but till now still can not find a good 1s brushless which can provide 40-50g of thrush.


How about these?
TODD
http://www.microbrushless.com/productsG1.htm
http://www.micronradiocontrol.co.uk/gp_motor.html
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Old Aug 31, 2011, 08:00 PM
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Singapore
Joined Nov 2007
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Hi Todd, I saw these motors but the price bit too high for my budget. Now I am thinking of AP05 motor to run on 1s, not sure if any one tested this setup before.
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Old Sep 03, 2011, 11:12 AM
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United States, CA
Joined Jul 2010
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Here's my micro stryker(First build that flies!!). Haven't flown it at the park yet, but it did fly into the trees in my backyard.
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Old Sep 03, 2011, 07:51 PM
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Minneapolis, Minnesota
Joined Jul 2007
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It appears you're using the ELE servo on the brick for one control and an external servo for the other..? Why the extra servo, you should be able to use the two servos on the brick.. Unless you haven't got a TX that'll do elevons? Nice looking plane, btw!

Jay
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Old Sep 03, 2011, 09:15 PM
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Originally Posted by Faethor View Post
It appears you're using the ELE servo on the brick for one control and an external servo for the other..? Why the extra servo, you should be able to use the two servos on the brick.. Unless you haven't got a TX that'll do elevons? Nice looking plane, btw!

Jay
Oh I see your point. Didn't think of that before. I'm using a DX5e, going to get a DX6i soon so I could remove that servo and save some weight.

How do you trim a flying wing? The one I built does not fly well at all. It will suddenly pitch downwards for no apparent reason. I have the battery all the way in front and the balance is around 1/3 of the length of the wing. If I pull inverted it will pitch up and spiral. When I glide tested it level it will tuck under and pitch downwards. What's wrong with the wing?
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Old Sep 03, 2011, 09:28 PM
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Southlake, TX
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Originally Posted by Cheese5 View Post
Oh I see your point. Didn't think of that before. I'm using a DX5e, going to get a DX6i soon so I could remove that servo and save some weight.

How do you trim a flying wing? The one I built does not fly well at all. It will suddenly pitch downwards for no apparent reason. I have the battery all the way in front and the balance is around 1/3 of the length of the wing. If I pull inverted it will pitch up and spiral. When I glide tested it level it will tuck under and pitch downwards. What's wrong with the wing?
I'm suprised it works this way with a DX5. I had to swap sides (brick on right, servo on left the get elevons to work with a DX5)

To get a wing to fly stable, you need reflex (washout) at the tips. The trailing edges of the elevons should visibly go up as you go out towards the tip from the root.
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Old Sep 03, 2011, 09:46 PM
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Manchester, UK
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Originally Posted by Cheese5 View Post
How do you trim a flying wing? ... the balance is around 1/3 of the length of the wing
The 1/3 rule is about area, not length, so you need the CG further back. I don't think the rule applies to flying wings though.

There used to be a flying wing CG calculator on geocities. I saved it a while ago so here it is. If you have Microsoft Excel, you can plug the numbers in and get an answer, If not, just refer to the diagram and use a calculator.

Incidentally, your fins look a bit big. It is possible to have too much fin. Maybe the drag on them is contributing to the problem.
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Old Sep 03, 2011, 10:01 PM
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Originally Posted by Andy2No View Post
The 1/3 rule is about area, not length, so you need the CG further back. I don't think the rule applies to flying wings though.

There used to be a flying wing CG calculator on geocities. I saved it a while ago so here it is. If you have Microsoft Excel, you can plug the numbers in and get an answer, If not, just refer to the diagram and use a calculator.

Incidentally, your fins look a bit big. It is possible to have too much fin. Maybe the drag on them is contributing to the problem.
Ok I plugged in the numbers (17cm for R, 4.3cm for T and 25 degrees for S) and got 12.99cm as the Cg. Is that from the back to front or from the front to back?

I removed the fins and tried smaller wingtip SFGs. Had the same problem How do you add washout(what is washout? first build for me that flies still new to all this).
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Old Sep 03, 2011, 10:02 PM
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Quote:
Originally Posted by UNGN View Post
I'm suprised it works this way with a DX5. I had to swap sides (brick on right, servo on left the get elevons to work with a DX5)

To get a wing to fly stable, you need reflex (washout) at the tips. The trailing edges of the elevons should visibly go up as you go out towards the tip from the root.
I had to reverse the aileron mechanically and then reverse the aileron on the DX5e to get it to work, weird. How do you add reflex?
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Old Sep 03, 2011, 10:54 PM
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Quote:
Originally Posted by Cheese5 View Post
Ok I plugged in the numbers (17cm for R, 4.3cm for T and 25 degrees for S) and got 12.99cm as the Cg. Is that from the back to front or from the front to back?... How do you add washout(what is washout? first build for me that flies still new to all this).
S is a distance marked on the diagram, rather than the angle.

I guess that makes S = 17 - 4.3 so 12.7cm, which makes the CG 8.066cm. I see your point; it's not marked on the diagram where you measure from. I believe it's from the front. Fortunately, the calculated CG is almost half way from the nose (slightly forward) so it won't matter too much if I'm wrong

Washout is a warp that makes the wingtips a little higher at the trailing edge than at the leading edge. Usually, only a small outer section of the wings gets the warp.

Reflex just means a bit of up elevator trim. A well balanced flying wing flies level with a couple of degrees or so of reflex.
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Last edited by Andy2No; Sep 03, 2011 at 11:27 PM. Reason: mistyped value for S. CG is right though.
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Old Sep 03, 2011, 10:58 PM
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Originally Posted by Andy2No View Post
S is a distance marked on the diagram, rather than the angle.

I guess that makes S = 17 - 4.3 so 12.3cm, which makes the CG 8.066cm. I see your point; it's not marked on the diagram where you measure from. I believe it's from the front. Fortunately, the calculated CG is almost half way from the nose (slightly forward) so it won't matter too much if I'm wrong

Washout is a warp that makes the wingtips a little higher.

Reflex just means a bit of up elevator trim. A well balanced flying wing flies level with a couple of degrees or so of reflex.
Oh didn't see that. So 8cm, that would mean the last few flights I've had were extremely nose heavy... I'll add some washout, already have reflex on the wing.
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Old Sep 03, 2011, 11:16 PM
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Cheese5,

I edited that shortly after, while you were typing. The wing tips are twisted up at the back, is what I meant.

Here's a diagram. I borrowed it from here:
http://www.laboratoridenvol.com/para...ign/voute.html
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Old Sep 03, 2011, 11:34 PM
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Southlake, TX
Joined Jan 2008
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Here is a picture of the ME163 Komet from the Deutches Museum in Munich to show reflex on an actual flying wing.



The Ange of Incedence of the wing is positive to longitudinal axis of the plane (shown as the centerline in my diagram) at the root and negative at the tip.

This is the proper way to set up a stable flying wing so that it creates maximum lift, without being prone to tip stalling.

If it's good enough for the fastest plane in WWII, it should be good enough for a micro wing.
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