Bob's JL F-4 "Crash Analysis"
03-15-2010, 02:21 PM
#8
RE: Bob's JL F-4
ORIGINAL: Countryboy
Agreed... and looks like it was flying well up to that point. At least it wasn't a structural failure!
Agreed... and looks like it was flying well up to that point. At least it wasn't a structural failure!
I agree.. I wonder what his antenna orientations and positions were? And if he checked the ant. positioning with a flight log before flight.
03-15-2010, 02:37 PM
#9
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RE: Bob's JL F-4
Would be interested in complete power system setup: pack brand and specs? redunduncy? regulator? etc.
Sorry to see that, completely sucks and couldn't have happened to a nicer guy. We're all pulling for you Bob.
Also wonder about the sounds..... really strange. Iwonder if things didn't wad up in there and take out the RF and stab mech?
Sorry to see that, completely sucks and couldn't have happened to a nicer guy. We're all pulling for you Bob.
Also wonder about the sounds..... really strange. Iwonder if things didn't wad up in there and take out the RF and stab mech?
03-15-2010, 02:54 PM
#10
RE: Bob's JL F-4
what is a LIFE battery? i'm sure it's a typo but curious otherwise. damn shame if it boiled down to prelaunch batt check but been there done that.
total bummer
i would've swore at the ground after impact beginning with an F and ending with a drawn out K
ORIGINAL: pilot98
I was there with Bob and the battery died. He was using a LIFE battery, voltage was 6.5 no load after we recovered the battery. Nominal should be 6.6.
I was there with Bob and the battery died. He was using a LIFE battery, voltage was 6.5 no load after we recovered the battery. Nominal should be 6.6.
03-15-2010, 03:03 PM
#12
My Feedback: (1)
RE: Bob's JL F-4
Sorry for your loss, we have run batt backup systems for years even before getting into jets. With the new radio systems of today it is quit simple to do and in this case may have saved your bird. I would say the two areas that are the life blood of any model are Batteries and a good fuel delivery system. We have all seen good planes go down only to find out a problem with one of those two items. BUMMER 
]
03-15-2010, 04:14 PM
#17
RE: Bob's JL F-4
LiFe isn't A123. It's similar, but not the same thing.
Was the pack fully charged before the flight? Were two batteries used? I'm not sure is Kelly was speaking about his experience or about Bob's plane.
Was the pack fully charged before the flight? Were two batteries used? I'm not sure is Kelly was speaking about his experience or about Bob's plane.
03-15-2010, 05:13 PM
#20
My Feedback: (1)
RE: Bob's JL F-4
Hm...Murphys law... again...?
Damn if it was the charger settings. But I do not understand why not redundant battery system was used in the first place (but I guess it would not have helped in this case - both batteries would probably not been charged anyway in this situation).
/Bo
Damn if it was the charger settings. But I do not understand why not redundant battery system was used in the first place (but I guess it would not have helped in this case - both batteries would probably not been charged anyway in this situation).
/Bo
03-15-2010, 05:29 PM
#21
My Feedback: (1)
RE: Bob's JL F-4
I know some guys don't believe in the two battery system but given how lite and compact they are these days its just a good idea IMO.
Models have become so much larger then in past years and with that the radio manufactures have been trying to keep pace with more powerful servos but they drink more juice to get that torque.
Whatever battery chemistry you choose to go with is a personal choice but having a backup system is the only way to go. Just by running two batteries with separate switches doubles you chances of not loosing a bird, plus it helps feed all those big servos.
I know some may come on and say they have thousands of flights with only one battery and I don't doubt that for a second, but I also know a Skydiver with over 1000 jumps and no main chute fail and he stills packs a backup chute !!!!!!
Again, sorry for your loss.
Models have become so much larger then in past years and with that the radio manufactures have been trying to keep pace with more powerful servos but they drink more juice to get that torque.
Whatever battery chemistry you choose to go with is a personal choice but having a backup system is the only way to go. Just by running two batteries with separate switches doubles you chances of not loosing a bird, plus it helps feed all those big servos.
I know some may come on and say they have thousands of flights with only one battery and I don't doubt that for a second, but I also know a Skydiver with over 1000 jumps and no main chute fail and he stills packs a backup chute !!!!!!
Again, sorry for your loss.
03-15-2010, 05:54 PM
#22
My Feedback: (67)
RE: Bob's JL F-4
Sorry to hear your loss.
I have the same things happened to me. I have 2 A123 batteries on JR1222. Exactly like your F-4, during final approach, plane went into fail safe, shut down the engine and then spiraled down to the ground. Because it was low and slow so the damage was only to the airframe. All hook ups were still on, and my data logger's flashing 4.0V! Took the batteries out and charged them again on the same A123 charger, and it's peaked at 175 mah on 1 battery and 575 mah on the other. I suspect that I am not getting full charge on the batteries so they both ran out of juice over time. Now, I will use 2 different chargers (another redundancy) to charge my batteries. Any better suggestions? Please advise.
Mike
I have the same things happened to me. I have 2 A123 batteries on JR1222. Exactly like your F-4, during final approach, plane went into fail safe, shut down the engine and then spiraled down to the ground. Because it was low and slow so the damage was only to the airframe. All hook ups were still on, and my data logger's flashing 4.0V! Took the batteries out and charged them again on the same A123 charger, and it's peaked at 175 mah on 1 battery and 575 mah on the other. I suspect that I am not getting full charge on the batteries so they both ran out of juice over time. Now, I will use 2 different chargers (another redundancy) to charge my batteries. Any better suggestions? Please advise.
Mike
03-15-2010, 06:24 PM
#24
RE: Bob's JL F-4
Mike, what charger are you using? I've had over 200 flights on A123 batteries in my 35% 3D plane and the packs were always charged with a Fromeco Ion Cube. I know of many 3D/IMAC pilots using the Ion Cube to charge A123 packs without a problem.
03-15-2010, 06:32 PM
#25
My Feedback: (67)
RE: Bob's JL F-4
A123 Fromeco and same charger Fromeco Ion Cube with the orange color boards. That was supposed to be the proven setup that my flying buddy used on all his jets without failure. He had sent it back for inspection and hopefully we can find out the real cause of it.
During my approach, the L/G was in down position, but we can see the sequence of engine shut down and then plane rolls to the right and snap, like what I had set up when fail safe kicks in. It's a slower process than the F4 experienced.
Mike
During my approach, the L/G was in down position, but we can see the sequence of engine shut down and then plane rolls to the right and snap, like what I had set up when fail safe kicks in. It's a slower process than the F4 experienced.
Mike
ORIGINAL: dubd
Mike, what charger are you using? I've had over 200 flights on A123 batteries in my 35% 3D plane and the packs were always charged with a Fromeco Ion Cube. I know of many 3D/IMAC pilots using the Ion Cube to charge A123 packs without a problem.
Mike, what charger are you using? I've had over 200 flights on A123 batteries in my 35% 3D plane and the packs were always charged with a Fromeco Ion Cube. I know of many 3D/IMAC pilots using the Ion Cube to charge A123 packs without a problem.