TF GS P47 Build - yeah another bloody one!!
06-19-2009, 05:03 PM
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RE: TF GS P47 Build - yeah another bloody one!!
sweatpea do not agree with what you are saying, not having a go at you just stating what I understand based on my professional training.
"If you use the batt-share it does not double your capacity. It simply gives you the capacity of both batteries just like if you plugged them both directly into the RX. It gives you the advantage of drawing both batteries down equally and protection against a shorted battery draining the good battery... "
If you plug 2 batteries in as you say then both packs are in parrallel. Basic Ohms law calculations will show that you do in fact double capacity. E=IR
2 x battery in series, capacity is the same but voltage doubles.
2 x battery in parrallel capacity doubles, voltage is the same.
Same as having 2 batteries in a large truck, they are wired in series to give 24volts however a lot of 4 wheel drive type vehciles here use dual batteries in parallel to increase total battery capacity so they can run other things like huge banks of spotlights etc etc.
I do feel we are all heavily over engineering the battery side of things in our models with far too much reliance on complicated circuitry to do the job. If you want isolated packs then use a simple diode on the standby pack. If main packs go low in voltage by 0.6v then the diode will pass current and you are on standby pack. You then get single battery capacity and the standby pack is only in use if main packs goes flat or dies.
If you want to to draw on both packs then simply put them in parallel with 2 switches. I have run that set up for 15 years with not one problem.
Some discussion on what happens if a cell shorts. Yes can happen but it does not short the entire pack, the pack in question will simply go from say 6v to 4.8v I'm sure we have all seen old packs like that where they will not come up when charging, that is ashorted cell in most cases. does it drain the other pack? No it does not. Typically what will happen though is that the shorted cell will draw a large instantaneous current while it is shorted, as the short is blown away the cell then becomes open circuit like a blown fuse. Hence no current can pass through that pack, that isolates the oher pack and you keep flying oblivious.
However if you do what I do before each flight and test that the model operates on each battery by opening and closing each switch to verify you will pick up that you have a dead battery. Pre - flight checks, remember those?
If however you want lots of circuits boards with potential for those to fail then fill your boots, personally the less electronics I can have in a model the better it is with far less chance of failures. Espcially with the high chance of solder joint failures due to poor quality wave soldering technicques which I can assure you is not NASA / MIL Spec for soldering!
Simple, easy, cheap and works. QED
If on the other hand you want to use lipos etc then that is a whole new can of works and you need lots of jelly bean machines to make it work. I have not yet delved into Lipos yet simply because I see them as damn dangerous despite their huge capability.
"If you use the batt-share it does not double your capacity. It simply gives you the capacity of both batteries just like if you plugged them both directly into the RX. It gives you the advantage of drawing both batteries down equally and protection against a shorted battery draining the good battery... "
If you plug 2 batteries in as you say then both packs are in parrallel. Basic Ohms law calculations will show that you do in fact double capacity. E=IR
2 x battery in series, capacity is the same but voltage doubles.
2 x battery in parrallel capacity doubles, voltage is the same.
Same as having 2 batteries in a large truck, they are wired in series to give 24volts however a lot of 4 wheel drive type vehciles here use dual batteries in parallel to increase total battery capacity so they can run other things like huge banks of spotlights etc etc.
I do feel we are all heavily over engineering the battery side of things in our models with far too much reliance on complicated circuitry to do the job. If you want isolated packs then use a simple diode on the standby pack. If main packs go low in voltage by 0.6v then the diode will pass current and you are on standby pack. You then get single battery capacity and the standby pack is only in use if main packs goes flat or dies.
If you want to to draw on both packs then simply put them in parallel with 2 switches. I have run that set up for 15 years with not one problem.
Some discussion on what happens if a cell shorts. Yes can happen but it does not short the entire pack, the pack in question will simply go from say 6v to 4.8v I'm sure we have all seen old packs like that where they will not come up when charging, that is ashorted cell in most cases. does it drain the other pack? No it does not. Typically what will happen though is that the shorted cell will draw a large instantaneous current while it is shorted, as the short is blown away the cell then becomes open circuit like a blown fuse. Hence no current can pass through that pack, that isolates the oher pack and you keep flying oblivious.
However if you do what I do before each flight and test that the model operates on each battery by opening and closing each switch to verify you will pick up that you have a dead battery. Pre - flight checks, remember those?
If however you want lots of circuits boards with potential for those to fail then fill your boots, personally the less electronics I can have in a model the better it is with far less chance of failures. Espcially with the high chance of solder joint failures due to poor quality wave soldering technicques which I can assure you is not NASA / MIL Spec for soldering!
Simple, easy, cheap and works. QED
If on the other hand you want to use lipos etc then that is a whole new can of works and you need lots of jelly bean machines to make it work. I have not yet delved into Lipos yet simply because I see them as damn dangerous despite their huge capability.
06-19-2009, 09:10 PM
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RE: TF GS P47 Build - yeah another bloody one!!
Old Tom, The oleo will travel 1" when fully compressed. In your picture there appears to be only 1/4" between the top of bottom door , which travels with the oleo and the wire which you'll convert to ball linkage. To better illistrate what I'm speaking of go to Rob C post 824 on page 33 and compare with his post 832 on page 34. Just to be sure. Regards, Allen
06-19-2009, 10:36 PM
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RE: TF GS P47 Build - yeah another bloody one!!
fiddling around with the wing today. Have put pylons aside till the fourmost release mechs arrive next week.
Found a few little dings in the top of the wing that I have some pink bog on dying at the moment plus some over the original holes I did for the .50 cals.
Found a few little dings in the top of the wing that I have some pink bog on dying at the moment plus some over the original holes I did for the .50 cals.
06-20-2009, 12:10 AM
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RE: TF GS P47 Build - yeah another bloody one!!
found my hidden stash of Fourmost bomb release mechanisims so working on centre pylon at the moment. The pylon itself is done but trying to fabricate the sway bars. Eeeek
06-20-2009, 06:35 AM
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RE: TF GS P47 Build - yeah another bloody one!!
ORIGINAL: Peter_OZ
sweatpea do not agree with what you are saying, not having a go at you just stating what I understand based on my professional training.
"If you use the batt-share it does not double your capacity. It simply gives you the capacity of both batteries just like if you plugged them both directly into the RX. It gives you the advantage of drawing both batteries down equally and protection against a shorted battery draining the good battery... "
If you plug 2 batteries in as you say then both packs are in parrallel. Basic Ohms law calculations will show that you do in fact double capacity. E=IR
2 x battery in series, capacity is the same but voltage doubles.
2 x battery in parrallel capacity doubles, voltage is the same.
Same as having 2 batteries in a large truck, they are wired in series to give 24volts however a lot of 4 wheel drive type vehciles here use dual batteries in parallel to increase total battery capacity so they can run other things like huge banks of spotlights etc etc.
I do feel we are all heavily over engineering the battery side of things in our models with far too much reliance on complicated circuitry to do the job. If you want isolated packs then use a simple diode on the standby pack. If main packs go low in voltage by 0.6v then the diode will pass current and you are on standby pack. You then get single battery capacity and the standby pack is only in use if main packs goes flat or dies.
If you want to to draw on both packs then simply put them in parallel with 2 switches. I have run that set up for 15 years with not one problem.
Some discussion on what happens if a cell shorts. Yes can happen but it does not short the entire pack, the pack in question will simply go from say 6v to 4.8v I'm sure we have all seen old packs like that where they will not come up when charging, that is ashorted cell in most cases. does it drain the other pack? No it does not. Typically what will happen though is that the shorted cell will draw a large instantaneous current while it is shorted, as the short is blown away the cell then becomes open circuit like a blown fuse. Hence no current can pass through that pack, that isolates the oher pack and you keep flying oblivious.
However if you do what I do before each flight and test that the model operates on each battery by opening and closing each switch to verify you will pick up that you have a dead battery. Pre - flight checks, remember those?
If however you want lots of circuits boards with potential for those to fail then fill your boots, personally the less electronics I can have in a model the better it is with far less chance of failures. Espcially with the high chance of solder joint failures due to poor quality wave soldering technicques which I can assure you is not NASA / MIL Spec for soldering!
Simple, easy, cheap and works. QED
If on the other hand you want to use lipos etc then that is a whole new can of works and you need lots of jelly bean machines to make it work. I have not yet delved into Lipos yet simply because I see them as damn dangerous despite their huge capability.
sweatpea do not agree with what you are saying, not having a go at you just stating what I understand based on my professional training.
"If you use the batt-share it does not double your capacity. It simply gives you the capacity of both batteries just like if you plugged them both directly into the RX. It gives you the advantage of drawing both batteries down equally and protection against a shorted battery draining the good battery... "
If you plug 2 batteries in as you say then both packs are in parrallel. Basic Ohms law calculations will show that you do in fact double capacity. E=IR
2 x battery in series, capacity is the same but voltage doubles.
2 x battery in parrallel capacity doubles, voltage is the same.
Same as having 2 batteries in a large truck, they are wired in series to give 24volts however a lot of 4 wheel drive type vehciles here use dual batteries in parallel to increase total battery capacity so they can run other things like huge banks of spotlights etc etc.
I do feel we are all heavily over engineering the battery side of things in our models with far too much reliance on complicated circuitry to do the job. If you want isolated packs then use a simple diode on the standby pack. If main packs go low in voltage by 0.6v then the diode will pass current and you are on standby pack. You then get single battery capacity and the standby pack is only in use if main packs goes flat or dies.
If you want to to draw on both packs then simply put them in parallel with 2 switches. I have run that set up for 15 years with not one problem.
Some discussion on what happens if a cell shorts. Yes can happen but it does not short the entire pack, the pack in question will simply go from say 6v to 4.8v I'm sure we have all seen old packs like that where they will not come up when charging, that is ashorted cell in most cases. does it drain the other pack? No it does not. Typically what will happen though is that the shorted cell will draw a large instantaneous current while it is shorted, as the short is blown away the cell then becomes open circuit like a blown fuse. Hence no current can pass through that pack, that isolates the oher pack and you keep flying oblivious.
However if you do what I do before each flight and test that the model operates on each battery by opening and closing each switch to verify you will pick up that you have a dead battery. Pre - flight checks, remember those?
If however you want lots of circuits boards with potential for those to fail then fill your boots, personally the less electronics I can have in a model the better it is with far less chance of failures. Espcially with the high chance of solder joint failures due to poor quality wave soldering technicques which I can assure you is not NASA / MIL Spec for soldering!
Simple, easy, cheap and works. QED
If on the other hand you want to use lipos etc then that is a whole new can of works and you need lots of jelly bean machines to make it work. I have not yet delved into Lipos yet simply because I see them as damn dangerous despite their huge capability.
06-20-2009, 06:40 AM
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RE: TF GS P47 Build - yeah another bloody one!!
I understand now. I'll get that taken care of.
It's a good thing you caught that before I made it permanent. I hate redoing stuff once they're glued. It wouldn't have been the first time.[sm=bananahead.gif]
Thanks for having a keen eye.[sm=shades_smile.gif]
It's a good thing you caught that before I made it permanent. I hate redoing stuff once they're glued. It wouldn't have been the first time.[sm=bananahead.gif]
Thanks for having a keen eye.[sm=shades_smile.gif]
06-20-2009, 06:42 AM
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06-20-2009, 06:50 AM
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RE: TF GS P47 Build - yeah another bloody one!!
ORIGINAL: Peter_OZ
here is today's paltry efforts
here is today's paltry efforts
Is that a home made Belly Tank Bracket. It looks really slick.
Show Lots of pictures. I may want to coppy that if I see I'm running out of time for finishing this summer.
I think Rescue Squad planes had belly tanks. Need to find out for sure. Any one have any info on that?
06-20-2009, 06:54 AM
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RE: TF GS P47 Build - yeah another bloody one!!
the center bit is a aerotech one which I have molds for. The release mech is a fourmost unit. The brass sway bar and belly brace is home made using K&S brass. The adjustment bolt is functional and ahs a locknut, Once the tank is on the screws are would out to brace it during flight. I'll be able to drob the cetre line tank with the wing mounted bombs.
06-20-2009, 09:12 AM
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RE: TF GS P47 Build - yeah another bloody one!!
Old Tom. Good enough. I know I would have done the same thing if I hadn't seen Rob's post. So we should thank Rob and all these guys contributing to this forum. regards Allen
06-20-2009, 09:01 PM
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RE: TF GS P47 Build - yeah another bloody one!!
ORIGINAL: athflyby
Old Tom. Good enough. I know I would have done the same thing if I hadn't seen Rob's post. So we should thank Rob and all these guys contributing to this forum. regards Allen
Old Tom. Good enough. I know I would have done the same thing if I hadn't seen Rob's post. So we should thank Rob and all these guys contributing to this forum. regards Allen
Everyone has been extremely helpful on this thread. I have even made some new friends because of this thread.
I'm greatfull to all. I'm having a great time building this plane.[sm=thumbs_up.gif]
06-21-2009, 03:09 AM
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RE: TF GS P47 Build - yeah another bloody one!!
ditto!
We had the scale fest at our club today and it bucketed down, still got one flight in withthe 1/4 scale Cub. Lovely landing into some puddles which through up showers of spray in a most realistic fashion
No work on th 47 as little man wanted me to build his model plane with him.
We had the scale fest at our club today and it bucketed down, still got one flight in withthe 1/4 scale Cub. Lovely landing into some puddles which through up showers of spray in a most realistic fashion
No work on th 47 as little man wanted me to build his model plane with him.
06-21-2009, 01:38 PM
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RE: TF GS P47 Build - yeah another bloody one!!
Just a quick comment on rx battery packs. The Lithiums being used are lithium-ion, not lithium-poly. The li-ion are not as much of a hazard to use as the li-po's. And most have quite a lot more capacity. However, they are more expensive than nimh or nicads.
06-21-2009, 05:30 PM
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RE: TF GS P47 Build - yeah another bloody one!!
Vanguard
Not sure if your post is a question or just a statement
Just my 2cents worth, more expensive Yes, more capacity Yes, and not as much of a hazard Li-pol's Yes, down side is due to the difference in voltage you must use regulators= more connections = adds more points of potentical failutes, along with the cost of new tech/ chargers etc.
Up grading is a good thing to a point.
Now I will go back to my dish and lay down to see if my ribbs will quit hurting (long story and not for this thread)
Bob T
06-21-2009, 05:34 PM
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RE: TF GS P47 Build - yeah another bloody one!!
One of the clubs I belong to Madison County R/C Fliers, had our anual fun flie. A Great time was had by all. Two casualties. One electric got to close to the ground with the tail and broke the H stabilizer on one side. Another guy hit the uprights on the limbo tree. He may have to buy a new kit. I'm happy to report that neater one of those was me.
I can go back to working on the 47 cause I don't need to fix anything. Yes!!!!!!![sm=49_49.gif]
I can go back to working on the 47 cause I don't need to fix anything. Yes!!!!!!![sm=49_49.gif]
06-21-2009, 08:08 PM
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RE: TF GS P47 Build - yeah another bloody one!!
rt,
I said at the beginning of my post it was a comment, therefore, not a question. It was in response to someones comment about the hazards of li po batteries. So I just pointed out that for receiver packs we use li ion packs. Your other points were correct. I already used regulators on my 6.0 volt nimh to avoid any issues when they were fully charged so that was no addition. I also was lucky enough to already have a charger that would handle all battery types except A123. Enough said, you guys can get back to your P47 post.
Old Tom,
Glad all your planes returned in one piece today. I got a set of keys, to the mower shed, made for you this weekend. I will get them to you the next time we fly, maybe Tuesday. Have a good one.
Mike
I said at the beginning of my post it was a comment, therefore, not a question. It was in response to someones comment about the hazards of li po batteries. So I just pointed out that for receiver packs we use li ion packs. Your other points were correct. I already used regulators on my 6.0 volt nimh to avoid any issues when they were fully charged so that was no addition. I also was lucky enough to already have a charger that would handle all battery types except A123. Enough said, you guys can get back to your P47 post.
Old Tom,
Glad all your planes returned in one piece today. I got a set of keys, to the mower shed, made for you this weekend. I will get them to you the next time we fly, maybe Tuesday. Have a good one.
Mike
06-22-2009, 09:26 PM
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RE: TF GS P47 Build - yeah another bloody one!!
Got a little more progress today.
Have the panel lines on the ailerons and the flaps and have the rivet lines laid out.
Even have rivets on on side of one aileron.
Have the panel lines on the ailerons and the flaps and have the rivet lines laid out.
Even have rivets on on side of one aileron.
06-23-2009, 09:19 PM
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RE: TF GS P47 Build - yeah another bloody one!!
ORIGINAL: Peter_OZ
tis a fun job [:'(]
tis a fun job [:'(]
No work on the 47. Got wore out at the Flying field. It's a lot more fun to go flying when you don't have to glue things back together.
I found out today that I wasn't so bad on landing the planes as I taught. The landing gear was fatigued and gave on landing and that was why I was braking props. It had me psyched out. I reinforced the gear and flew with the same prop all day.I still need work but I'm on my way. Maybe by the time I finish the 47 I'll be able to land it. At least that is the goal.
06-23-2009, 09:53 PM
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RE: TF GS P47 Build - yeah another bloody one!!
hey that is great, sounds like you are getting in the groove. Get that landing tunnel vision going and you will be sweet.
06-24-2009, 04:25 PM
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RE: TF GS P47 Build - yeah another bloody one!!
I'm leaving on a 4-day motorcycle trip with my non flying buddies early in the morning.
I'll be back Sunday night to see what kind of mischief you guys got into in my absence.
So behave yourselves while I'm gone.
I'll be back Sunday night to see what kind of mischief you guys got into in my absence.
So behave yourselves while I'm gone.
06-25-2009, 03:13 AM
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RE: TF GS P47 Build - yeah another bloody one!!
ORIGINAL: Tseres
I'm leaving on a 4-day motorcycle trip with my non flying buddies early in the morning.
I'll be back Sunday night to see what kind of mischief you guys got into in my absence.
So behave yourselves while I'm gone.
I'm leaving on a 4-day motorcycle trip with my non flying buddies early in the morning.
I'll be back Sunday night to see what kind of mischief you guys got into in my absence.
So behave yourselves while I'm gone.
mate I'm prone to getting into michief though at the moment if is just the large organisation office political game