Vritual gurney flap

[manchild]

Here it is Mikey_s, I've done it anyway.

Hope it is now more understandable how NACA duct would feed whole wing cross section.



It could be even done Renault style (like Honda Monza update)

[kilcoo316]

The blade interior would need to be something like:



But I'll stress again, you need a pressure ratio to perform vectoring of 5+, and a specific mass flow rate 1.2 x mean mass flow rate [that'll be kg/s.m^2] to fill the boundary layer effectively.

I doubt the two ducts would provide the mass flow, and I know they won't even begin to provide the compression necessary.

[manchild]

kilcoo, would one big additional NACA duct below original one or several smaller ones on each endplate provide enough pressure? Is that possible at all or impossible regardless on capacity of ducts?

[kilcoo316]

Providing the mass flow may be possible.

The pressure rise is simply impossible, as I said a few pages back the most you can do is double the pressure coefficient [in inviscid flow at a stagnation point].


But you need a pressure ratio of around 5 or more to do real effective TVC - so you need a pump.


To put it in perspective - you'd need a 2 stage axial compressor to acheive that kind of pressure ratio.



edit: the PR of 5-10 is for nozzle applications - I'll see if I can find a more suitable comparision if I've time later. But, I'd imagine it would still be something similar.

[manchild]

Would one-way valve just after duct change anything?

Regarding pump... wouldn't air pump be considered as movable aero?

[zac510]

Surely it may be easier to run a hydraulic line up through a hollowed endplate to a couple of solenoids inside the element to change the wing shape.

Very illegal though

[Reca]

kilcoo, would one big additional NACA duct below original one or several smaller ones on each endplate provide enough pressure? Is that possible at all or impossible regardless on capacity of ducts?

Basic rule of thermodynamics : “there are no free lunches”. You not only are asking for a free lunch you even want to get paid to eat...

[manchild]

I'm trying to understand this correctly but I see two possible meanings:

1. I'm expecting kilcoo to do my math while I get the glory (which isn't the truth since I lost any patent right the very moment I've put my idea online).

2. I'm expecting airflow and aerodynamic shapes to do impossible things.

Which one is it Reca?

[kilcoo316]

Would one-way valve just after duct change anything?

Regarding pump... wouldn't air pump be considered as movable aero?

A valve wouldn't change a thing.


Uhm the pump might be movable.... but if you can somehow mount it within the wheel...


Others suggested a feed from the exhaust - you would have the required mass flow and pressure for sure.... if you could get a pipe large enough through the endplate and could get a light enough substance to carry it without overheating.


Fluidic TVC and nozzle control isn't used on aircraft, despite having an easily accessible flow of compressed air [from the engine core itself] - they simply don't perform as well as mechanical nozzles at the moment (and I don't know if that is ever going to change).


As Reca says - those damn free lunches are hard to find!

[Mikey_s]

Kilcoo,

it seems to me you have a good understanding of this aero stuff - rather than blowing to do the gurney flap thang, how about my suggestion of doing a bit of sucking to re- attach air flow onto the low pressure trailing edge...

I take your points about dirt, flies atc, but this part of the vehicle is on the back side of a more or less vertical plane on the high d/f circuits (should take care of the flies, they'll all end up on the high pressure side!) and presumably centrifugal force would take care of any larger particles.

My guess is that the 'suction' required need not be too large and even if some of the pores got blocked you might still get a free sandwich, even if there were no starter, dessert wine, or coffee

[manchild]

Fluidic TVC and nozzle control isn't used on aircraft, despite having an easily accessible flow of compressed air [from the engine core itself] - they simply don't perform as well as mechanical nozzles at the moment (and I don't know if that is ever going to change)

That includes Sea Harrier?

[kilcoo316]

That includes Sea Harrier?

Its mechanical - it swivels the nozzles to achieve TVC.



I mean injecting air into the nozzle to perform the vectoring - totally different method of trying to achieve the same thing.

[manchild]

I had in mind static nozzles on tip of the wings that function similar to reactive "steering" on space ships.

[kilcoo316]

how about my suggestion of doing a bit of sucking to re- attach air flow onto the low pressure trailing edge...

Hard to say - no way can I give an any way quantitative answer obviously...


But, suction is/has been researched mainly for boundary layer control of transonic wings.

In the sharp adverse pressure gradient of the shockwave on a transonic wing, the boundary layer grows rapidly. Downstream of this, using suction will remove the stagnating flow and allow energised flow to get down nearer the surface, dramatically reducing drag. It works well here because you are only sucking flow away from a small area of the wing - the bit downstream of the shockwaves [assuming you have avoided oscillating shocks in designing the wing/aerofoil sections].



For an F1 rear wing 2nd element, after, what, 25-30%? of the chord, the flow will begin to seperate - to keep it attached after this point will require constant suction all the way to the trailing edge (and probably quite a bit of suction at that) - which is a much larger operation than 5% of the chord length (if even that) for transonic flow control on an aircraft wing with the internal volume to hold the pumps and piping for such an operation.


To do the suction, you'll need the pump, and piping to the rear wing. Is the weight and power loss (you'll have to slave power from the engine to run this, do F1 cars have alternators?) really worth it? I would expect not.

[Reca]

Which one is it Reca?

Let’s put it this way, you are asking a NACA duct to increase the total pressure while the aim of a NACA duct design (or of any duct), that includes the selection of some geometrical parameters to adapt it to the particular case, is to minimize the pressure loss...

Anyway, even using a pump or any mean to create the required pressure jump, you didn’t lost patent rights when you put it online, you never had them given that blowing air before/around/inside an airfoil leading edge/trailing edge/suction side etc etc isn’t really a new concept, it’s been made in several different ways.

Mikey_s :

on the Benzing’s book “Dall’aerodinamica alla potenza in F1” there are results from a test made some years ago in the windtunnel with a wing having an hole on the suction side connected with an internal camera. They also closed the hole and compared results and the system was giving a clear advantage in that particular case (it was the wing of an endurance car).
Here the results and the assembly (sorry for the quality, I don’t have scanner here so I had to take pics) :
[IMG:152:130]http://img482.imageshack.us/img482/2365 ... 7jj.th.jpg[/img]
[IMG:152:130]http://img148.imageshack.us/img148/7435 ... 3sc.th.jpg[/img]
Anyway I’m not so sure that the suction side of the rear wing main element is an area very protected from dirt that could close the hole, consider that flow from exhausts isn’t very distant from there.

Edit : on the http://www.benzing.it website there’s a pic of the wing (the one on the right in the first row)
http://www.benzing.it/enrico.ali.htm