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Old Oct 21, 2008, 05:53 AM
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Ipoh, Perak Malaysia
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Quote:
Originally Posted by teslahed
I tried to add some dyhedral when i was building it;
I read somewhere that dihedral is not necessary for these swept wing designs. Every 10 deg (if I remember correctly) of sweep backwards is equivalent to 1 deg of dihedral. So, there is a built-in dihedral. As for the commercial wings I have bought (Watts Hyperwing), there is no dihedral on the bottom of the wing as it is flat all across. I mean you can lay it flat on the table and can see that there is not dihedral.

It flies well and is not overly sensitive.

chewy
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Old Oct 21, 2008, 08:44 AM
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Quote:
Originally Posted by chewytm
I read somewhere that dihedral is not necessary for these swept wing designs. Every 10 deg (if I remember correctly) of sweep backwards is equivalent to 1 deg of dihedral. So, there is a built-in dihedral. As for the commercial wings I have bought (Watts Hyperwing), there is no dihedral on the bottom of the wing as it is flat all across. I mean you can lay it flat on the table and can see that there is not dihedral.

It flies well and is not overly sensitive.

chewy
I suspect that larger wings lack dyhedral to gain manouverability on the roll axis, and added it to mine because i thought being so tiny it would benefit from increased stability, but it is possible i have the theory wrong so i'd be interested to hear more about dyhedral on flying wings.

If you gain stability from the sweap angle of the wing, surely this stability would be equal upsidown as well?

Just waiting for my new 3 cell battery to charge then i will try my new tiny wing again with a bit more power than the 2 cell.
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Old Oct 21, 2008, 08:50 AM
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Ipoh, Perak Malaysia
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My hyperwing flies just as nice upside-down or rightside-up. The hyperwing upper surface is thicker at the centre and thinner at the tips. If you should put it on the table upside-down, it wont't lie flat. It will have, in effect, some dihedral.

chewy
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Old Oct 21, 2008, 09:25 AM
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Quote:
Originally Posted by chewytm
My hyperwing flies just as nice upside-down or rightside-up. The hyperwing upper surface is thicker at the centre and thinner at the tips. If you should put it on the table upside-down, it wont't lie flat. It will have, in effect, some dihedral.

chewy
Since my wing is quite thin and is even thickness along the span should i assume it wasn't a waste of time building in dyhedral?

The wind is so bad i can't tell exactly how self righting it is as i have to intervene to keep it up even if it does has some stability.

I just got back from flying with an 800mah 3 cell battery - it now has a thrust to weight ratio of about 1:1 and performs considerably better as a result. Loops, rolls etc all more easily. I'm very happy with my minature version of this excellent design :-D

I'm still looking forward to getting some calm weather to try flying it in clean air.
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Last edited by teslahed; Oct 21, 2008 at 09:39 AM.
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Old Oct 21, 2008, 08:55 PM
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Ipoh, Perak Malaysia
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Whatever works, man. If it flies well, then it's good!

chewy
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Old Oct 22, 2008, 07:09 AM
Wing & A Prayer
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Mobile, Alabama
Joined Nov 2005
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Congratulations! I've not had any wing yet with dihydral, these aren't typically self righting machines but you seem willing to experiment so go for it and find out what works .

On my throws comment: There's nothing saying you can't add in more and more throw till you start to get negative returns I really only meant for those first flights till you proved your design. I have dual rates programmed in for my wing but I rarely use the low rates even for takeoff.
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Old Oct 22, 2008, 07:23 AM
Crash Master
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Indianapolis, IN
Joined Sep 2001
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While sweep does add some stability, there's nothing like a little bit of dihedral for some self-righting. It doesn't take much, 1-2 makes a big difference. It does make it less stable inverted, but it just depends on your personal flying style, which is better.

If a wing has thinner tips, you can join it together with the top flat, adding dihedral, rather than symetrical, or even with some annehedral... I've seen some scratch-built wings which unintentionally came out with annehedral, and preferred to fly inverted
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Old Oct 22, 2008, 07:58 AM
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Chester Va
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When I built my wing like this, I mounted a 3/8 motor stick down the center of the wing. The bottom of the wing glued to the motor stick, the top of the wing glued to itself. In the end, it left it with just a bit of dihedral, maybe 1" overall, but it flew much better then the first symmetrical version (for me). Wing tips as well, extend 1" below and 1-3/4" above the wing for added stability. Was a load of fun to fly, but I need a 20" version, lol..
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Old Oct 22, 2008, 01:38 PM
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Quote:
Originally Posted by sobamaflyer
Congratulations! I've not had any wing yet with dihydral, these aren't typically self righting machines but you seem willing to experiment so go for it and find out what works .<
Thanks. I've only been building 7 months now and flying for 5 (none of them flew the first 2 months) so i do appreciate the encouragement. Only about half of all the planes i've built so far have flown well. The other half didn't fly at all, but i try to see this as part of the challenge.

Quote:
Originally Posted by sobamaflyer
On my throws comment: There's nothing saying you can't add in more and more throw till you start to get negative returns I really only meant for those first flights till you proved your design. I have dual rates programmed in for my wing but I rarely use the low rates even for takeoff.
Don't worry about it; always best to er on the side of caution and thinking about it i would have assumed a smaller wing to be twitchier anyway. Either the dyhedral or the general good design that i copied from must have helped...

I just had the chance to fly the thing in calmer conditions and it flies lovely. Very stable, glides nicely, feels light and responsive and seems to stay up a good 10 to 15 mins running near full throttle on an 3 cell 800mah battery.

The only thing i am going to change it to trim down the vertical wing tip stabalisers as i think they don't need to be so big and are causing excess drag.

If anyone wants a small wing i'd have to recomend building one of these bluecore wings at a reduced scale as it does seem to work great! EPP makes for a very strong wing (9.5 oz all up with the 3cell) but i'm sure bluecore would be fine too and lighter without the need for carbon fibre.
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Old Nov 08, 2008, 08:36 AM
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I've attached one of those little 'finger torch' LED raver toys to the nose. I could only get a blue one but as soon as i find a red and a green i'm doing the wing tips as well. Velcro seems strong enough for an easily removable fastening mechanism. Hopefully i'll be able to fly the thing now the clocks have changed (UK) and i've got less daylight.

The mobile phone is just being used to prop up the nose. I find i get interference otherwise.

Sobamaflyer may be interested to hear that I've swapped the plane over to my old none 2.4ghs analogue radio transmitter. I had to dial back the travel on the servos mechanically using the holes on the arms as it became way too twitchy and would fall out the sky whenever i used full deflection.
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Last edited by teslahed; Nov 08, 2008 at 08:44 AM.
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Old Nov 16, 2008, 06:14 PM
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After the success of my first smaller EPP version of this design i thought i'd have another go.

This time i was going for maximum lightness without sacrificing too much strength as well as good gliding performance for soaring off small hills in light winds. I'm hoping that a longer thiner wing with less sweap will produce these results.

Obviously it's not finished yet. The long piece on the nose will be folded over and it still needs wingtips and electronics.

I'm not sure exactly where the centre of gravity should be. Any suggestions welcomed...

The new one is bottom in the picture below the previous miniwing;

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Old Nov 17, 2008, 02:47 PM
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Finished picture;



All up weight is 7 and a half ounces although i think i will have to add a bit of weight in the nose to get the CoG right.

Edit - well it flies. Nicely as well.

Compared to my other mini wing it flies slower and glides a little better, roles slower (longer wing span presumably) and is a little slower in top speed perhaps but not much.

It floats a bit nicer than the previous one as well, being a couple of ounces lighter.

In the end i only had to put a single 2 pence coin in the nose to get the CoG right.
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Last edited by teslahed; Nov 18, 2008 at 08:41 AM.
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Old Dec 04, 2008, 11:01 AM
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Just thought i'd check in and say i'm getting a lot of millage out of this basic design.

My current project is to make an EPP pusher prop jet with a eurofighter like delta shape and front canards. To achieve this I've just varied the geometry of the basic bluecore wing and am going to add a nose. In the picture you can see the carbon fibre sticking out that will reinforce the nose once i have one.

I could just have used depron or EPP to make a basic flat wing but i thought i'd try something differet :-) Hopefully my airfoil wont be too far off.

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Old Dec 04, 2008, 11:35 AM
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trying to delete accidental double post...
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Old Dec 04, 2008, 10:48 PM
Cumulus Altimus
FASTBEN's Avatar
KELLER TEXAS
Joined Feb 2002
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hi all this is the best and most informative thread i have read......i will be building one for sure im new to the wings so i may ask some stupid questions and all,btw i have a just go fly 300df pusher witch size wing should i go for i need the speeder.
thanks
ben
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