Re: [Flightgear-devel] f16 speedbrakes

Jon S. Berndt writes: > This would be good to see in a plot. Can you do that? i guess jsbsim can do it but i never tried it. any pointers? --alex-- -- | I believe the moment is at hand when, by a paranoiac and active | | advance of the mind, it will be possible (simultaneously with | | auto

Re: [Flightgear-devel] f16 speedbrakes

This would be good to see in a plot. Can you do that? Jon > -Original Message- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of > Alex Romosan > Sent: Saturday, September 06, 2008 5:06 PM > To: FlightGear developers discussions > Subject: Re: [

Re: [Flightgear-devel] f16 speedbrakes

Jon S. Berndt writes: > I don't know if this matters, but remember that not too long ago we > added the ability to enter aero coefficients in several coordinate > systems - including BODY and WIND, etc. so if i were to represent the wind tunnel data in x,y,z axis then the drag due to horizontal t

Re: [Flightgear-devel] f16 speedbrakes

On Fri, Sep 5, 2008 at 11:54 PM, Erik Hofman <[EMAIL PROTECTED]> wrote: > > > > I also see that (I'm only looking at the speedbrakes effects). > > Two things are unclear for me: > > 1. The values of alpha in f16.xml are exactly half those in NASA's > > TP1538 report. > > 2. The values of the coeff

Re: [Flightgear-devel] f16 speedbrakes

> > Of course you need to transform the data from body axes to wind axes > first.. > > Erik I don't know if this matters, but remember that not too long ago we added the ability to enter aero coefficients in several coordinate systems - including BODY and WIND, etc. Jon -

Re: [Flightgear-devel] f16 speedbrakes

Fabian Grodek wrote: > On 9/4/08, *Alex Romosan* <[EMAIL PROTECTED] > > wrote: > > Erik Hofman writes: > > > Alex Romosan wrote: > >> can you give me a pointer as to where i could get this data? thanks. > >> > > Search for NASA Technical Paper 15

Re: [Flightgear-devel] f16 speedbrakes

On 9/4/08, Alex Romosan <[EMAIL PROTECTED]> wrote: > > Erik Hofman writes: > > > Alex Romosan wrote: > >> can you give me a pointer as to where i could get this data? thanks. > >> > > Search for NASA Technical Paper 1538 > > i've been looking at it but i can't figure out the relationship > between

Re: [Flightgear-devel] f16 speedbrakes

Erik Hofman writes: > Alex Romosan wrote: >> can you give me a pointer as to where i could get this data? thanks. >> > Search for NASA Technical Paper 1538 i've been looking at it but i can't figure out the relationship between the number in the report and the numbers in the flightgear model.

Re: [Flightgear-devel] f16 speedbrakes

On Sun, 2008-08-31 at 12:31 +0200, Fabian Grodek wrote: > On 8/30/08, Erik Hofman <[EMAIL PROTECTED]> wrote: > > ... But I don't see any pitching moment effect; from > > what I see in NASA TP 1538 > I > > understand there is a pitc

Re: [Flightgear-devel] f16 speedbrakes

On 8/30/08, Erik Hofman <[EMAIL PROTECTED]> wrote: > > > ... But I don't see any pitching moment effect; from > > what I see in NASA TP 1538 I > > understand there is a pitch-down effect from the speedbrakes. > > > It looks like you don't have the latest version o

Re: [Flightgear-devel] f16 speedbrakes

Erik Hofman writes: > Alex Romosan wrote: >> can you give me a pointer as to where i could get this data? thanks. >> > Search for NASA Technical Paper 1538 thanks. --alex-- -- | I believe the moment is at hand when, by a paranoiac and active | | advance of the mind, it will be possible (si

Re: [Flightgear-devel] f16 speedbrakes

Fabian Grodek wrote: > > Erik, > In the F16 aero config file I see there's indeed an increase in lift > for certain speedbrakes deflection, accompanied by the expected huge > increase in drag. But I don't see any pitching moment effect; from > what I see in NASA TP 1538

Re: [Flightgear-devel] f16 speedbrakes

On 8/29/08, Erik Hofman <[EMAIL PROTECTED]> wrote: > > > What happens (with regard to the fly-by-wire system) is this: > > Speedbrake deflection causes a pitching moment which the FCS > automatically compensates because there is no pitching moment requested > by the pilot. > > Erik Erik, In the F

Re: [Flightgear-devel] f16 speedbrakes

Alex Romosan wrote: > can you give me a pointer as to where i could get this data? thanks. > Search for NASA Technical Paper 1538 Erik - This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build

Re: [Flightgear-devel] f16 speedbrakes

Erik Hofman writes: > Sorry, I got the data from windtunnel test data performed by NASA. can you give me a pointer as to where i could get this data? thanks. --alex-- -- | I believe the moment is at hand when, by a paranoiac and active | | advance of the mind, it will be possible (simultaneou

Re: [Flightgear-devel] f16 speedbrakes

Alex Romosan wrote: > Erik Hofman writes: > >> Alex Romosan wrote: >>> I felt what happens! It seemed my face was being pulled from my >>> skull. I couldn't believe how effective those speed brakes were. An >>> F-16's speed brakes are located at the back of the fuselage either >>> side of

Re: [Flightgear-devel] f16 speedbrakes

gerard robin wrote: >> A Only my 2 cents, if the question is not stupid :) > How does the fly-by-wire, regarding the speedbrake lift effect ? What happens (with regard to the fly-by-wire system) is this: Speedbrake deflection causes a pitching moment which the FCS automatically compensates be

Re: [Flightgear-devel] f16 speedbrakes

On ven 29 août 2008, Erik Hofman wrote: > Alex Romosan wrote: > > Erik Hofman writes: > >> Believe me, this is correct behavior, and this is why: > > > > i found a nice article about flying in an f16: > > > > http://www.avweb.com/news/skywrite/181916-1.html > > > > this is the part about the spee

Re: [Flightgear-devel] f16 speedbrakes

Erik Hofman writes: > Alex Romosan wrote: >> >> I felt what happens! It seemed my face was being pulled from my >> skull. I couldn't believe how effective those speed brakes were. An >> F-16's speed brakes are located at the back of the fuselage either >> side of the engine nacelle, and re

Re: [Flightgear-devel] f16 speedbrakes

Alex Romosan wrote: > Erik Hofman writes: > >> Believe me, this is correct behavior, and this is why: > > i found a nice article about flying in an f16: > > http://www.avweb.com/news/skywrite/181916-1.html > > this is the part about the speed brakes: > > "Here's where the speed brakes come

Re: [Flightgear-devel] f16 speedbrakes

Erik Hofman writes: > Believe me, this is correct behavior, and this is why: i found a nice article about flying in an f16: http://www.avweb.com/news/skywrite/181916-1.html this is the part about the speed brakes: "Here's where the speed brakes come in handy, I'll open em up. And you'll

Re: [Flightgear-devel] f16 speedbrakes

Alex Romosan wrote: > i hate to bring this up again but i still think the speedbrakes don't > work as they should, instead generating quite a lot of lift. i've > tested this on final approach at about 160-170 knots, speedbrakes on; > i can keep the plane level. retract the speedbrakes, the plane s

Re: [Flightgear-devel] f16 speedbrakes

Erik Hofman writes: > Ok, tested it again. The only way I could reproduce your scenario is > not to have the throttle near idle. > As I did state earlier, the speeedbrakes of the F-16 are quite small > and as it turns out the engine can easily produce enough thrust to > overcome the increased drag

Re: [Flightgear-devel] f16 speedbrakes

Erik Hofman writes: > Ok, tested it again. The only way I could reproduce your scenario is not > to have the throttle near idle. > As I did state earlier, the speeedbrakes of the F-16 are quite small and > as it turns out the engine can easily produce enough thrust to overcome > the increased d

Re: [Flightgear-devel] f16 speedbrakes

Ok, tested it again. The only way I could reproduce your scenario is not to have the throttle near idle. As I did state earlier, the speeedbrakes of the F-16 are quite small and as it turns out the engine can easily produce enough thrust to overcome the increased drag. Erik --

Re: [Flightgear-devel] f16 speedbrakes

Alex Romosan wrote: > hmm, i don't know how the real f-16 behaves but i still find the > current behaviour a bit strange. level flight, ~350 knots extend the > brakes the aircraft pitches up slightly and really starts to climb (no > effect on the speed at all). push the nose down (quite a lot) to b

Re: [Flightgear-devel] f16 speedbrakes

Erik Hofman writes: > Ok, I think I have most of it figured out. I might even consider > upgrading the status to 'production' the way it is now. hmm, i don't know how the real f-16 behaves but i still find the current behaviour a bit strange. level flight, ~350 knots extend the brakes the aircra

Re: [Flightgear-devel] f16 speedbrakes

Ok, I think I have most of it figured out. I might even consider upgrading the status to 'production' the way it is now. Erik - This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest

Re: [Flightgear-devel] f16 speedbrakes

Alex Romosan wrote: > i think there is still something wrong with the speedbrakes but i am > not sure how to quantify this. basically i think they provide way too > much lift (which makes me suspect there is a sign problem somewhere). > the effect is more pronounced at slower speeds (250 - 300 kn

Re: [Flightgear-devel] f16 speedbrakes

Erik Hofman writes: > You were right, I had to map speedbrake-pos-norm to > speedbrake-pos-rad/deg by using an aerosurface scale section. i think there is still something wrong with the speedbrakes but i am not sure how to quantify this. basically i think they provide way too much lift (which ma

Re: [Flightgear-devel] f16 speedbrakes

Alex Romosan wrote: > Erik Hofman writes: > >> Looking at the code it looks like setting speed-break-pos-norm should be >> the same as setting speed-break-pos-rad so the patch shouldn't have any >> effect. > > look at aero/coefficient/CDDsb or fcs/mag-speedbrake-pos-rad in the > property browse

Re: [Flightgear-devel] f16 speedbrakes

Alex Romosan wrote: > Erik Hofman writes: > >> Looking at the code it looks like setting speed-break-pos-norm should be >> the same as setting speed-break-pos-rad so the patch shouldn't have any >> effect. > > look at aero/coefficient/CDDsb or fcs/mag-speedbrake-pos-rad in the > property browse

Re: [Flightgear-devel] f16 speedbrakes

Erik Hofman writes: > Looking at the code it looks like setting speed-break-pos-norm should be > the same as setting speed-break-pos-rad so the patch shouldn't have any > effect. look at aero/coefficient/CDDsb or fcs/mag-speedbrake-pos-rad in the property browser. when you deploy the speed brak

Re: [Flightgear-devel] f16 speedbrakes

Alex Romosan wrote: > i noticed that on the f16 the speedbrakes have no effect at all and i > managed to track it down to the fact that the various coefficients use > fcs/mag-speedbrake-pos-rad on input which never gets set anywhere (so > it is always 0). > > digging through the cvs logs i found t

[Flightgear-devel] f16 speedbrakes

i noticed that on the f16 the speedbrakes have no effect at all and i managed to track it down to the fact that the various coefficients use fcs/mag-speedbrake-pos-rad on input which never gets set anywhere (so it is always 0). digging through the cvs logs i found that in version 1.17 of f16.xml t