0
Airowpoint

Mylar ribs good/bad

Recommended Posts

Quote

I'm wondering if my deflectors are doing me any good at all.



I have the same type of deflectors on my suit.I usually form them with my fingers if my suit has been in my gear bag to give them shape as the material is stiff and will hold a shape. When I punch it out and roll my elbows forward more I can watch the ones that aren't fully formed open up more.As for them working, ask Jari, he has several pictures from the wind tunnel testing where you can see smoke trails moving over the top of the wing on suits with and without deflectors.
"It's just skydiving..additional drama is not required"
Some people dream about flying, I live my dream
SKYMONKEY PUBLISHING

Share this post


Link to post
Share on other sites
I was also having one of my more brilliant ideas.
What if you remove some of the stitching on the S3 front deflectors so you are combining two of the smaller arcs into one bigger arc. You will end up with 4 big arcs (and a small bit) instead of 9 small arcs. They will then look like the S3S front deflectors which apparently are better...
Tristan
Will you answer "NO" to my next question?

Share this post


Link to post
Share on other sites
Quote

I was also having one of my more brilliant ideas.
What if you remove some of the stitching on the S3 front deflectors so you are combining two of the smaller arcs into one bigger arc. You will end up with 4 big arcs (and a small bit) instead of 9 small arcs. They will then look like the S3S front deflectors which apparently are better...



I think the old smaller deflectors (shouldnt they be called 'attachers', as they seem to attach wind to the wing, rather then deflecting it?:P) tend to just be blown flat onto the wing. The newer deflectors have a stifner in them that makes sure they stay open. If you could find a way to also keep them open?

There's no rigging like home rigging :)
JC
FlyLikeBrick
I'm an Athlete?

Share this post


Link to post
Share on other sites
completly wrong Jarno
lower pressure is on the upper part of the wing, and nothing but this will keep the deflector open. Same principle apply to any type of any deflector or air inlet on WS. The only thing which may keep the deflector or air inlet closed or out of function is the improper position, wrong size, wrong shape or wrong material.
Robert Pecnik
[email protected]
www.phoenix-fly.com

Share this post


Link to post
Share on other sites
Quote

completly wrong Jarno
lower pressure is on the upper part of the wing, and nothing but this will keep the deflector open. Same principle apply to any type of any deflector or air inlet on WS. The only thing which may keep the deflector or air inlet closed or out of function is the improper position, wrong size, wrong shape or wrong material.



Tristan was commenting earlyer on his inlets/deflectors being closed/shut...it was just my redneck guestemate as to why:ph34r:
It not something I've seen upclose..

I think thats the reason why you are designing good wingsuits and and both Tristan and I are not (and shouldnt):P
JC
FlyLikeBrick
I'm an Athlete?

Share this post


Link to post
Share on other sites
Just a question for robi or anyone else:

Deflectors are intended to create a turbulent flow that will stick to the wing longer, resulting in the separation point being closer to the tail. This results in more lift.

However, in doing so, it converts the laminar (smooth) flow to a turbulent one, which produces less lift. But it sticks to the wing longer, which is good.

By adding deflectors, you are sacrificing that efficient, laminar flow for a "more sticky", but less efficient, turbulent flow. How do you know when that trade-off becomes worth sacrificing the laminar flow? Or is the flow always going to be turbulent due to the fact that wingsuits typically aren't very smooth surfaces?

Share this post


Link to post
Share on other sites
it's not quite that simple

I think you are confusing laminar vs. turbulent flow with boundary layer seperation.

The flow will be laminar or turbulent based on the reynolds number. This mostly relates to the 'speed' of the flow.

Boundary layer seperation is dependant on surface roughness (which is why golf balls have dimples, it makes them fly further), so by increasing surface roughness you will delay the onset of boundary layer seperation. you will however be increasing the drag due to skin friction, but you can decrease the form drag by keeping the boundary layer attached for longer along your surface.

All of this happens with turbulent flow, though. Laminar flow only occurs at really low Reynolds numbers and is not all that common in nature.

This is also why sharks have skin as rough as sandpaper.

Share this post


Link to post
Share on other sites
____________________________________________________
By adding deflectors, you are sacrificing that efficient, laminar flow for a "more sticky", but less efficient, turbulent flow. How do you know when that trade-off becomes worth sacrificing the laminar flow? Or is the flow always going to be turbulent due to the fact that wingsuits typically aren't very smooth surfaces?
___________________________________________________

in short :)Can you see the deflector on V1?! ;)
Regards
RoBi
Robert Pecnik
[email protected]
www.phoenix-fly.com

Share this post


Link to post
Share on other sites
Quote



Boundary layer seperation is dependant on surface roughness (which is why golf balls have dimples, it makes them fly further), so by increasing surface roughness you will delay the onset of boundary layer seperation. you will however be increasing the drag due to skin friction, but you can decrease the form drag by keeping the boundary layer attached for longer along your surface.



I see, so maybe laminar flow has nothing to do with it and i'm really talking about the boundary layer separation. You mentioned that an increase in surface roughness delays boundary layer separation. Is this due to the fact that a rough surface creates more turbulence in the boundary layer, hence having a similar effect as the deflectors? Or is it something else?

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

0