Stewbronco
Well Known Member
Searched this but came up short on pictures .... anyone got pictures of battery mounted on front side of firewall ? Thanks. Stew
Van's Air Force
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Battery on firewall
- Thread starter Stewbronco
- Start date
hcccs
Well Known Member
Rotate your starter solenoid
I would consider rotating your starter solenoid 90 degrees if you?re planning any aerobatic flight. Bob Knuckols talks about this in his AeroElectric book. The G load on the aircraft could close the starter contact and engage the starter damaging your ring gear.
Here's the installation in my RV4
I would consider rotating your starter solenoid 90 degrees if you?re planning any aerobatic flight. Bob Knuckols talks about this in his AeroElectric book. The G load on the aircraft could close the starter contact and engage the starter damaging your ring gear.
hcccs
Well Known Member
Interesting! I searched my copy of AeroElectric Connection but couldn't find it. What page is it?
HFS
Well Known Member
FWIW
I tested both of the contactors shown back in June of 2017. Following are the steps taken for testing:
1. Removed end caps to allow disassembly
2. Removed and weighed the contactor shaft assembly (not including spring)
3. Replaced the shaft assembly (with spring) back into the housing
4. Placed the assembly, upside down, on a sensitive digital jewelers scale
5. With an LED connected across the input/output terminals of the contactor, I pushed down on the housing until the LED came on
6. Recorded the force required, and then divided it by the "tare" weight of the
shaft to yield the "G" force necessary to initiate contact.
7. Results (YMMV): Master Relay - "Tare" Wt. = 2.1oz. Force to make contact = 13oz. 13/2.1 = 6.2 G's. Since this switch is on all the time, there will be no change in its condition, unless you apply more than 6.1 G in the negative direction.
Starter Relay - "Tare" Wt. = 1.5 oz. Force to make contact = 1lb 6oz. 22/1.5 = 14.66 G's. At this level it would be pretty hard to make unintended contact during aerobatic maneuvers.
Disclaimer: These results are only for the units tested - I don't know how other brands of contactors may very as to their performance.
HFS
YMMV
I tested both of the contactors shown back in June of 2017. Following are the steps taken for testing:
1. Removed end caps to allow disassembly
2. Removed and weighed the contactor shaft assembly (not including spring)
3. Replaced the shaft assembly (with spring) back into the housing
4. Placed the assembly, upside down, on a sensitive digital jewelers scale
5. With an LED connected across the input/output terminals of the contactor, I pushed down on the housing until the LED came on
6. Recorded the force required, and then divided it by the "tare" weight of the
shaft to yield the "G" force necessary to initiate contact.
7. Results (YMMV): Master Relay - "Tare" Wt. = 2.1oz. Force to make contact = 13oz. 13/2.1 = 6.2 G's. Since this switch is on all the time, there will be no change in its condition, unless you apply more than 6.1 G in the negative direction.
Starter Relay - "Tare" Wt. = 1.5 oz. Force to make contact = 1lb 6oz. 22/1.5 = 14.66 G's. At this level it would be pretty hard to make unintended contact during aerobatic maneuvers.
Disclaimer: These results are only for the units tested - I don't know how other brands of contactors may very as to their performance.
HFS
YMMV
Page 8-98
Page 8-98 of AeroElectric Connection. At first Bob says it's unlikely that G forces will close the contactor as he tells a story about it but then in the next paragraph, "The starter contactors we stock and recommend have an operating axis that usually mounts on the firewall with its operating axis at right angles to aerodynamically induced g-loads and are immune to this influence."
Here's a link to the starter contactors he's talking about. As you can see, they are oriented at 90 degrees and in line with the longitudinal axis of the aircraft if you mount it on the firewall.
Cheap insurance to protect your engine IMHO. You have to ask yourself, do you feel lucky?
Page 8-98 of AeroElectric Connection. At first Bob says it's unlikely that G forces will close the contactor as he tells a story about it but then in the next paragraph, "The starter contactors we stock and recommend have an operating axis that usually mounts on the firewall with its operating axis at right angles to aerodynamically induced g-loads and are immune to this influence."
Here's a link to the starter contactors he's talking about. As you can see, they are oriented at 90 degrees and in line with the longitudinal axis of the aircraft if you mount it on the firewall.
Cheap insurance to protect your engine IMHO. You have to ask yourself, do you feel lucky?
A1AVIATON47
Well Known Member
HEAT
ITS GOING TO GET HOT THERE.
ITS GOING TO GET HOT THERE.
So is that why it?s called the hot battery bus?
Just kidding, before anyone goes ballistic
Brian Vickers
Well Known Member
PC 680 pics
I have some pics to share from my 4 under construction. I'm using an off the shelf aluminum battery box made for the PC680 that was purchased somewhere on-line. It wasn't expensive and can't remember the cost but it's a common Google search item. I have a single 1/4" bolt through the flange on each side that attaches to a nut plate in the firewall structure. One of the photos shows the back side of the firewall and the nut plates are visible. I've removed the battery numerous times and would do it the same way again. Once the two bolts are removed the whole assembly slides straight up. Plenty of room for magneto wires and other peripherals. Holds the battery tight with no movement that I can detect or wiggle.
https://photos.app.goo.gl/fVGvAsbarqkPbLjr8
https://photos.app.goo.gl/ahGx7QGtA9LcaDSs6
https://photos.app.goo.gl/9afnnbkthjeWkeBs9
I have some pics to share from my 4 under construction. I'm using an off the shelf aluminum battery box made for the PC680 that was purchased somewhere on-line. It wasn't expensive and can't remember the cost but it's a common Google search item. I have a single 1/4" bolt through the flange on each side that attaches to a nut plate in the firewall structure. One of the photos shows the back side of the firewall and the nut plates are visible. I've removed the battery numerous times and would do it the same way again. Once the two bolts are removed the whole assembly slides straight up. Plenty of room for magneto wires and other peripherals. Holds the battery tight with no movement that I can detect or wiggle.
https://photos.app.goo.gl/fVGvAsbarqkPbLjr8
https://photos.app.goo.gl/ahGx7QGtA9LcaDSs6
https://photos.app.goo.gl/9afnnbkthjeWkeBs9
Brian Vickers
Well Known Member
Finished project
I finished my RV-4 in the summer of 2014 and keep it in a hangar at Bremerton airport. You are welcome to take a look and sit inside. You can email me.
I finished my RV-4 in the summer of 2014 and keep it in a hangar at Bremerton airport. You are welcome to take a look and sit inside. You can email me.
Stewbronco
Well Known Member
Heat
Many thanks to all for responding..... wondering if the additional heat on forward side of firewall has been an issue for anyone in terms of functionality or longevity? Thanks again. Stew
Many thanks to all for responding..... wondering if the additional heat on forward side of firewall has been an issue for anyone in terms of functionality or longevity? Thanks again. Stew
