GEAR

Everything concerning FS and Aviation in general, and SAAB 91 Safir in particular is discussed here.
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mace
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GEAR

Post by mace » 16 Sep 2006, 21:00

Hallöchen zusamme,
mir ist aufgefallen, dass die 2 hinteren räder beim ein- und ausfahren kurz ein kleines stück rausfahren, dann wieder kurz einfahren und dann erst ganz ausfahren. ist das normal???
DANKE im vorraus

Marcel



P.S.: SUUUUUUUUUPER FLUGZEUG

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Alex
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Post by Alex » 16 Sep 2006, 21:12

Hi Mace,

As usually i didn't understand anything.
Can anyone translate for us ? :D
Maybe we can help.
Alex Petrochenko
SibWings developer

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Post by DNovet » 16 Sep 2006, 22:22

Yes, Alex, I can... ;)

Marcel is reporting, that when you either extend the landing-gear, the main wheels will extend a little bit, then retract again and just then extend fully.
And he asks, whether that is normal?

Cheers,

Daniel, having a look for himself...

mace
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Post by mace » 16 Sep 2006, 22:29

Vielen Dank fürs übersetzen auch von meiner seite.

Marcel

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Post by DNovet » 16 Sep 2006, 22:38

Ok, as I used to write in tech-logs:

"Aircraft jacked, System tested thoroughly by multiple gear swings. Found on lefthand main gear only, that on the first toggle, everything works normal, and in all following gear swings, the gear always swings once before locking in up-position or going down from up-position.

Due to otherwise normal working of the system, Transfer to DD for further examination."

Since this is only expirienced *after* the first extension or retraction (actually toggle, it doesn't matter which way), this might really be a problem in the model's animation.
Nevertheless, the landing-gear-mechanism *does* allow (and due to its nature has to have) a certain discrepancy of extension except for fully up and down-locked positions.
I think it's safe to say that it's a bug, that might very well be a feature... ;)

I think this bug will also go on the list for fixing until upgrade.

Marcel,
Habs getestet und bestätigen können, obwohl zumindest bei mir nur das linke Fahrwerk betroffen ist.
Auch passiert der Fehler nicht bei der ersten Zustandsänderung, sondern nur bei allen folgenden, beim ersten mal ists normal. Daher kann man schon darauf schliessen, dass dies ein bug ist, welcher in der Animation des Models zu suchen ist.
Allerdings ist es in der Tat normal, dass bei den Safir die beiden Hauptfahrwerke unterschiedliche Winkel haben können, was vom Mechanismus her kommt. Auch ein leichtes Schwingen des einen oder anderen Hauptfahrwerks kann normal sein.
Da dieser Fehler aber nicht beim ersten mal auftritt aber bei allen darauffolgenden Betätigungen, ist es wohl definitiv ein Bug.
Der auf die Liste kommt und jut is... :)

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Alex
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Post by Alex » 16 Sep 2006, 22:41

It happens sometimes IRL, so it's quite normal :)
But it can be fixed if that bothers.
I'll fix it
Alex Petrochenko
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snave
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Post by snave » 16 Sep 2006, 23:54

That could be a function of lowering the gear at too high an airspeed. The gear limiting speed is listed at just 175km/h (96 knots) for the B and D variants, and still only 200 km/h for the C...

The undercarriage is completely manual in operation, with a clever form of spring assistance. You can see how operating it at too high an airspeed would prevent the gear from functioning correctly, but that the act of getting the gear partially out would slow the aircraft to the point where the spring pressure overcomes the air pressure, and it deploys fully.

Frankly, I wouldn'y look to `fix` that unless it were to be shown as a persistent problem in operation BELOW gear limiting speed... if you see what I mean? :wink: Mace seems to have more problems with this bird than anyone else...
Simon Evans

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Post by DNovet » 17 Sep 2006, 00:07

Uuh...

Simon...

Have a look yourself...
Plane-view, from behind, slightly below waterline...

At least with the HB-DBL and *well* below gear-speed, the lefthand main-gear *does* swing indeed.

Cheers,

Daniel

snave
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Post by snave » 17 Sep 2006, 00:12

I wouldn't know, I fly Flight Sim, not Control Tower sim... but I'll make a special visit to spot view to check it out and see if it upsets my sensibilities. :roll:
Simon Evans

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Post by DNovet » 17 Sep 2006, 00:18

ROFL!

Simon, our opinions are extremely streamlined...

I totally agree, a plane is meant to be flown from the cockpit.
If it's meant to be flown from outside, then one would call it a "RC-Plane" and make it for Reflex, Aerofly or something similar... ;)
And I totally agree to the obvious sensibility of someone in this forum to outside-details... ;)

Either way, where's a point, there's a point... ;)

Cheers, mate! :)

snave
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Post by snave » 17 Sep 2006, 00:57

OK, so I see what he means, but for me there's no problem - it looks very similar to the way the Europe monowheel undercarriage system works - which apart from gliders, is the only hand-operated system I'm familiar with.

As I said, it's a spring-assisted manual undercarriage: There appears to be no mechanism in the cockpit for locking the gear up or down, just the lever for raising and lowering.

When lowering the gear, at the first part of the movement of the handle in the cockpit, the operating spring moves the undercarriage lock out of the cam that I presume is fitted to prevent the gear falling down if the spring fails and to provide a secure base when the gear is down and I perceive this `up and over` motion to be reflected in the way the gear deploys as it leaves the mechanism. The Europa wheel does something very similar - starts to move, pauses, theb continues.

Obviously, if Marcel is the expert on how the gear actually moves, then I defer to his knowledge, but otherwise I would say leave it as a `feature`, it looks real to me... :wink: Does it offend the sensibilities of the Safir owners? Probably not, but they don't have the benefit of Spot View in the real world like Mace does.
Simon Evans

Stefan
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Stefan

Post by Stefan » 18 Sep 2006, 02:37

Hi!

About the gear, "swinging".

This is normal on the Safir. We have jacked up our aircraft (a real Safir) several times and test the gear at our 100h inspections. The gear does this "swing". Even when the gear are in it's up and locked position it's still able to puch the gear up and down a bit. If you ever see a Safir flyby at low altitud check out the wheels and gear. It "wobbles" in and out a few centimeters as the aircraft flies through turbulent air.
NOT: The gear in the Safir is all mechanical. Only puchrods and chains to opperate it.

So please do not change this!

Best regards
/Stefan

snave
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Post by snave » 18 Sep 2006, 03:28

That I think, cuts it.

It's a `feature`!!!!!!!!!!!!! 8) :-D

Someone translate that for Mace, please. He's probably busy checking the tread pattern on the tyres by now. :lol:
Last edited by snave on 18 Sep 2006, 03:47, edited 1 time in total.
Simon Evans

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Andrey
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Post by Andrey » 18 Sep 2006, 03:35

snave wrote:
It's a `feature`!!!!!!!!!!!!! 8) :-D
Absolutelly ;) I was recomended by pilots that front gear on the Safir is pretty sensetive, besides that was proved by Daniel's and Till's real video.

Andrey
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Hakan_Olsson
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Post by Hakan_Olsson » 18 Sep 2006, 10:09

[quote="snave"]As I said, it's a spring-assisted manual undercarriage: There appears to be no mechanism in the cockpit for locking the gear up or down, just the lever for raising and lowering. [quote]

The locking mechanism is activated by a ninety degree twist of the gear lever handle.
When retracting the gear the force in the handle is quite high when you press it the last bit to the floor. It is very easy to to wobble the lever a little bit under certains conditions so the gear can move a bit randomly depending on the pilot.
If you like me, fly with your right hand you have to switch hand on the stick , retract the landing gear and hopefully not wobble the stick about to much. Seeing a Safir pitching up and down during gear operation must also be considered as normal.

Some pilots doesnt't tighten their seat harness until after the gear has been raised because they use their entire body weight to retract the gear litteraly standing on the pedals.

Best regards,
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Knorren
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Hope

Post by Knorren » 18 Sep 2006, 11:34

Håkan: Hope to see some yellow Safirs next time I visit Halmstad!
Regards
/Johan
Proud Pilot of KVZ and LAZ
http://www.f15fk.se
http://www.fcfk.com/fcfk/

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Hakan_Olsson
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Post by Hakan_Olsson » 18 Sep 2006, 11:41

Johan,

I'll do my best ! :D

Best regards,
Håkan
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SuredT
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Post by SuredT » 26 Sep 2006, 02:00

Hi,

The easiest way to retract the gear in real life is to push the stick a bit at the same time you push the gear lever down.
It takes a bit of practice, but once mastered is hardly noticeable from the outside.

It is the greatest excuse to do a low pass to the end of the runway.
Questioned by the authorities you can always say that otherwise you are unable to raise the gear, because it is too heavy to do otherwise. :-D

Sjoerd

Serge
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Not a gear for ladies !

Post by Serge » 27 Sep 2006, 14:57

...And you should have seen that gear moving franticaly up and down all along the runway, while the plane was yoddeling up and down at low altitude when a lady pilot was desperately trying to lift it and lock it up. Since it needed a considerable amount of strenght, an a good synchronisation to lock it in the up position by twinsting the handle to the right at the end of it's movement, ladies were barely able to do it.

Funy, when seen from the hangar ! :lol:
Serge

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