Berzerk - Composite chevron wing

[sean]

I finished my first bagged-wing model ealier this week, and so far it's had a few days wringing-out on the slope.

Bagging is a great way to build a slopie! The wings for this model would have taken about the same time to finish as a foamy with lots of strapping tape, spars and a neat Profilm covering job. I guess it will be quicker when I have a bit more experience.

I've named it the "Berzerk". Better not go into much detail here as I posted some info and pics on RCG:
www.rcgroups.com/forums/showthread.php?t=971194

[felix]

one word sean - WOW! top job and making me feel my beevo build looks more then a little half @rsed lol.

can't wait to get into bagging.

[chamm37]

NO AUSOME is the word ae.... Very nice saun....How much would you say it would be to make one of these ;D

[sean]

Thanks fellas, hopefully we can catch up for a fly soon. Chris - it's not a lot of work, the radio install was the hardest part but a bit more forethought would fix that.

I did find bagging very fiddly, but I'm sure with practice it will get much easier. Most important thing is to have a clean bench and absolutely everything laid out and ready before you mix any resin (I'm used to having a messy bench so that is unnatural for me). Also would have been smart to have a checklist to make sure you don't miss any steps - when bagging the first wing I forgot to cut the LE cloth, only remembered after I'd laid up the top and bottom skins on the mylars. It was a very hot day so had to work fast cutting the LEs before the epoxy started to go off....

[Pij]

How do you launch this thing? I can't see anywhere to hold, unless you do a discus launch.

It looks absolutely amazing.

[sean]

Thanks Pij . I launch it by grabbing onto the nose and throwing slightly down off the slope, doesn't need much speed to get flying that way. That suits me as I've never been much good launching while holding the TE (mind you my launching technique is down-right embarrasing for any plane).

[shane]

Great work Sean ,this is what you have been slaving away at.
Very brave to use carbon in your own design .
I'v been using a roller on the mylar when it's in the bag ,with just the right amount of pressure you can roll out things a bit and reduce pin holes also, where the leading edge tape doubles over the skin rolling will level it out by crushing the bottom layer into the foam a little.
Love to see the Berzerk in action soon . ;D

[thevon]

I've been hearing about this creation from Sean and it's been exciting, but the picture is incredible! It just looks amazing.

A couple of weeks ago he was saying he had cut the cores, and he stuck them together and put some little winglets on and tossed it in a paddock (just a bare blue foam toss-glider), and it flew beautifully! So he took it as a good omen that it could be a good flyer.

[sean]

He he, yeah I used some white foam cores I cut while getting my hot wire working. Just taped them together, balanced with a 20c piece and threw it around my yard. I used it to test whether flaps would make a difference. They helped slow this test glider down but unlike the finished version it needed some slight up elevon to balance the flaps.

[chamm37]

Hey sean i got a question for ya

Would you be able to program a fast mode with a Chevron wing. You know on the moldies and stuff how we have different modes for different situations like thermal and fast mode....Well i was wondering, with a 4 servo wing, would you be able to set up a fast mode with it

I was thinking you could have the flaps go up about 1-2mm or so or instead of the flaps, use the allerons...Do you think this would work or just cause hastles or just dont work at all


I am going to making another Ozprey and making it 4 servo wing just to see how it goes. Making it around the 1kg mark is my goal and will be putting in a ballast tube and everything so it will be for strong windy days at SC or DSing on the backside of a hill...I am really intreaged on how this will help the Ozprey fly haveing a 4 servo wing Cause i know from experience from my other Ozprey, it is a real pain to land as it is at 650grams simply becuase it is too fast, so i pupose having flaps, i will be able to slow it right down and land it at my feet and not all beeten up and scratched from a hard and fast landing ;D

Let us know your ideas about what you would think about the 4 servo wing Ozprey. I will make another thread for it but yer, any advice would be very helpful ;D


Regards,
Chris ;D

[sean]

Hi Chris,

I reckon you'd be better off using just two servos in the Ozprey.

Sean.

[chamm37]

So woudlnt you think that having flaps would make the Ozprey fly better

[sean]

No, I personally think you'd be better saving your time and money. Flaps work on a swept chevron wing because the outer elevons have a decent moment-arm to counteract the downward pitch caused by the flaps, plus a few other reasons related to the swept planform. They work on a plane with a tailplane for similar reasons. But you don't get that on a straight wing plank - instead you need to counteract the downward pitch of the flaps by deflecting the outer elevons up an equal amount and that doesn't tend to work very well. People have made it work but it takes a lot of fiddling (most seem to give up finding it too problematic). Plus from what I've seen the Ozprey lands reasonably slowly anyway, and it's made of EPP so just seems like a lot of complication for not much return.

Sean.

[sf2]

Hey sean, looks exceptionally good, so how does one go about doing the whole wing thing. I need to do some wings for my now fuses that I posted. Is everything you did on RCG, I know I'll go have a look, but seriously is the whole approach hard and what core type foam did yoou use, got a million other questions but will check RCG 1st and get back to you

[sf2]

Yup I got a milion questions.