Author Topic: Jabo bug in F4U  (Read 319 times)

Offline CpMorgan

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Jabo bug in F4U
« on: January 01, 2007, 10:26:17 AM »
Just experianced a bug with the jabo run I made last night in the MA Orange. I have film of the event. I'm diving on the target, setting up alignment, dropping at 500+ IAS, when the controls frieze and the plane pulls outa the dive and actually levels off. I have NO pitch control at this time. I'm fighting to get the nose down, but nothing works correctly. It begins at about 17 seconds into the film, and doesn't abate untill 28-30 seconds. I'm seriously at a loss as to why this is happening. This is not the first time it's happened, but it is the first time I've gotten it on film. I'm not sure how to attach the film to this post, but I'll be happy to forward it to you if necessary.

:confused:

Offline AKDogg

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Jabo bug in F4U
« Reply #1 on: January 01, 2007, 12:00:22 PM »
that strange as I been flying the hog for about 8 months and never experienced that.  I also have took the hog in a 610 mph dive, 615 it locks up.  Check your trim and makesure u don't have it on up trim.
AKDogg
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Offline CpMorgan

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Trim issue
« Reply #2 on: January 01, 2007, 12:12:42 PM »
OK,,I'll check it out. I've just re-created the situation in the TA with the same results, with film. I'll try with the trim setting a zero just to be sure.

Offline CpMorgan

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Testing info Update
« Reply #3 on: January 01, 2007, 02:54:48 PM »
Ok, here's an update. Let me begin by establishing the criteria. I'm using a Sidewinder Force Feedback 2 Joystick. It doesn't have any trim controls on the stick itself, so I use the keyboard to set trim. Combat trim is off. From 17K up, I dove for the groung in a typical Jabo dive, approximately 60 deg down nose angle. At 500+ IAS, the nose would start to climb back to a less severe AoA IF the Y axis trim is set at anything above zero. Also, if at anytime I used any Auto pilot settings, the Y trim would reset positive. So, before I began my last run, I intentionally set the Y trim to below zero or in the negative range on the scale. I achieved a 500-600 IAS dive before any "float" took place, and that was minor when it did happen. Also, I was in severe compression when it finally did occur. Thus, I have discovered something unknown to me before now. If this is old news to some of you guys, then I apologise for re-hashing this. But it came as a total suprise to me when it happened, and I had to figure out what was the cause. Anyone is welcome to re-create my experiance for yourselves, and view my films if you would send me an E-mail. Thanks.

Offline AKDogg

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Jabo bug in F4U
« Reply #4 on: January 01, 2007, 05:59:42 PM »
I am lazy so I use auto combat trim. lol  I got no problems with trim.  I do just well using the auto while I know other pilots swear by manuel trim.
AKDogg
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Offline Auger

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Jabo bug in F4U
« Reply #5 on: January 02, 2007, 01:10:08 PM »
Manual trim is fine for flying around, sometimes fighting if you stay near trim speed, but it will screw you up in a dive bombing situation.  The nose will tend to creep up on you in a dive unless the plane is trimmed for 400+ KIAS. Combat auto trim will attempt to keep the plane trimmed for the current speed, making it very useful in dive bombing situations.