Author Topic: FBW and Trim  (Read 6736 times)

SUBS17

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FBW and Trim
« on: January 29, 2008, 04:01:26 am »
I notice alot of trim is required to fly this Hornet thing is though that IRL you shouldn't have to trim as much due to the FBW. Does anyone know if there is a setting somewhere to fix this or is it a limitation of FSX?

Great Ozzie

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Re: FBW and Trim
« Reply #1 on: January 29, 2008, 06:19:37 am »
Subs, this was your operational experience as an F/A-18 driver?  :o

Rob O.

crim3

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Re: FBW and Trim
« Reply #2 on: January 29, 2008, 08:36:57 am »
As far as I know, the f18 has not fly by wire. That's something usual on the last generation fighters, but not in that generation. That's one of the things that has made the lovely f16 so special all this years (and so hard to simulate on a comercial sim).

Anyway, I use to fly a freeware Hawk (the jet trainer) for x-plane which had auto-trim (nothing comparable to FBW). Is it a usual feature on combat planes? It makes things a lot easier. Anybody knows?

Also, it is worth mentioning that it exists a plug-in for x-plane that simulates FBW. It puts itself between the joystick and the control surfaces and converts stick inputs in roll rates and g demands by the proper deflection of the control surfaces. With no other sim I have felt the chain Stick-FBW-Control Surfaces-Flight Model so authenticly.

SUBS17

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Re: FBW and Trim
« Reply #3 on: January 29, 2008, 11:20:31 am »
LMAO where did you hear that the Hornet doesn't have Fly By Wire? ;D
Quote
The F-18 incorporated a quadruply-redundant digital fly-by-wire flight control system, the first of its kind to be installed in a production aircraft. It works by having stick and rudder inputs being directed into a computer which interprets them and issues the appropriate commands to the various control surfaces. The FBW system will not allow the pilot to overstress the airframe. The system operates by the principal of majority vote. If one of the four systems disagrees with the other three, this is interpreted as a failure, and the dissenting system is ordered to shut down. FBW redundancy is such that should a second system fail, the remaining two systems can still operate the controls so long as they remain in agreement. In the unlikely event of all four systems failing, there are electrical backups for all control surfaces. There is even a direct mechanical backup for the horizontal tail surface which will give the pilot some degree of pitch control in an extreme emergency.


BTW I think the US Hornets were cat limited to 7.5gs can't remember where I read it though so in FSX it should not allow more than 7.5gs unless the pilot over rides it. (F-16s are limited to 9gs CAT3) No I'm not a Hornet driver either but I have come across the FBW trim topic in a few places and from some pilots the trim is minimal in FBW aircraft. Like only need to use it a little bit in cases where a bomb has been released off one wing or the fuel transfer etc.

crim3

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Re: FBW and Trim
« Reply #4 on: January 29, 2008, 12:25:33 pm »
I wrote the reply expecting something like that  :-\ Thanks for the info...
I was assuming that it didn't have because you can find lot of articles and discussions about the f16's FBW and not about others like the f18. Maybe is just that I have always been very inclined to the f16.

Hence, till which extend can we trust the fsx accelerator's f18 flight behaviour if it should be commanded through a FBW that has not been modeled? It's the same old flaw.

Aside all this, what about the non FBW planes with auto-trim? I still want to know if it is usual in combat planes or not.

SUBS17

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Re: FBW and Trim
« Reply #5 on: January 29, 2008, 09:31:07 pm »
Yeah there are alot of Falcon 4 forums with good discussions on the FBW/Trim and lockon forums also have had a few threads in the past but the best answers I've seen on the topic have been at the FighterOps forums where a real F-16 pilot talked about how often he uses trim. FSXs FBW is sort of modelled in that at lower speeds the aircraft will automatically lower its flaps but the FBW behaviour is not there eg if I pull back on the stick 10 degrees and release it should remain at 10 degree climb where as in FSX it requires trim to stay there.(should only require trim if I try to fly level inverted) The F-16s control setup is quite different from a Hornet the stick works off pressure it only moves about 1/4 of an inch. There is a comparrison by a real Hornet pilot on the F-16 somewhere on the Net who flew a Viper its quite good seeing his perspective on it.