Small Tail Caddy wrote:Hotrod, it is a PITA because of the way the battery is mounted.
It sets on top of the floor, between the seat rails. The seat only has about 6" of travel, a real PITA to get in.

As I recall, my 170 had oodles of easy-to-get-at room under the front seats - at least after I removed the skirts. What kind of battery is it? seems like one of the small ones (powersafe/odyssey type) should fit laying flat on the floor without hampering seat adjustment. I can see where only 6" of seat travel would be a PITA.

The bigger issue with batteries mounted where they never get warm (as in aft) in winter is that a cold battery never takes a full charge. So, every time you crank that engine up, you'll pull the battery down, and it won't fully re-charge. Next time you crank it, same thing. After a while, the battery is so weak it won't crank, and then you learn all about hand propping in the snow and cold.

MTV

mtv wrote:The bigger issue with batteries mounted where they never get warm (as in aft) in winter is that a cold battery never takes a full charge. So, every time you crank that engine up, you'll pull the battery down, and it won't fully re-charge..........

How cold are you talking? I haven't seen too much of this in western washington-- of course, I keep my airplane hangared. Maybe 24/7 outdoors and/or in colder climes it'd be a different story.

I too am planning moving the Battery from under the seat to the cargo area. I have a big concord battery and I hope to move it aft far enough to remove the huge chunk of lead in the rear. If I need more weight I'll add survival gear.

Good topic and I'm interested to see where this goes.

Anything colder than about +20 a conventional battery that doesn't ever get warm will gradually lose charge. If the battery is warm just prior to start, it'll generally be fine. I found this out operating out of Fort Yukon, etc in very cold weather. It's easy to put a battery blanket on the battery if it's aft, and connect it to your engine heater plug in, but it makes a LOT more sense to me to move the battery forward to the engine compartment if possible, for the reasons previously stated.

MTV

mountainmatt wrote:I too am planning moving the Battery from under the seat to the cargo area. I have a big concord battery and I hope to move it aft far enough to remove the huge chunk of lead in the rear. If I need more weight I'll add survival gear.

Good topic and I'm interested to see where this goes.

Matt, here's the setup you want. When I upgraded the engine I got suggestions to use ballast or even build some survival gear into the tail - since you're already losing useful to the heavier engine dead weight just didn't make sense. This preserved my CG, almost no change from the stock configuration. Downsides are the weight of the cables and, as has been discussed, being well removed from the warmth of the engine, but in this installation this made the best sense.

Perfect, thanks Vick.

I may be asking you another question or two when the time comes to move it aft.

Have I told you how awesome your 108 is lately?

mountainmatt wrote:Have I told you how awesome your 108 is lately?

Not afraid to rub it in, are you? Pre-buy may be happening this week

My dilemma is with the Pponk Super Eagle mod I'm doing it's supposed to add 45-50 lbs. that's all up front. I'm changing to the Lite wt. starter and the alternator loosing about 16 lbs with the 2. If I do the battery on the firewall I'll loose an additional what 20-25 lbs? With a net gain of 10-15 lbs but with a even more forward CG. Will 10 lbs in the tail counter the forward CG? And if you answer this today why aren't you out flyin, I've got an excuse

Glidergeek wrote:My dilemma is with the Pponk Super Eagle mod I'm doing it's supposed to add 45-50 lbs. that's all up front. I'm changing to the Lite wt. starter and the alternator loosing about 16 lbs with the 2. If I do the battery on the firewall I'll loose an additional what 20-25 lbs? With a net gain of 10-15 lbs but with a even more forward CG. Will 10 lbs in the tail counter the forward CG? And if you answer this today why aren't you out flyin, I've got an excuse

How's your pre-upgrade CG work for you? If it's good, I would think that the last thing you'd want to do is screw that up by putting even more weight up front on top of the bigger engine. Although since an odyssey/powersafe battery comes in at around 15 pounds including the bracket, that'd about even out with your weight loss from the light starter & alt --but losing the heavy aft-mounted battery & long cables would still move the CG way forward.
If an aft-mounted lightweight battery will give you enough oomph through the long cables to turn that bad boy over, that'd be another way to go. Lots easier, just drop in the new small battery & you're done. Except for the paperwork- no big deal on my battery install, but if you're IFR-cert'd you might need to do some load calc's to remain so.

mountainmatt wrote: I too am planning moving the Battery from under the seat to the cargo area. I have a big concord battery and I hope to move it aft far enough to remove the huge chunk of lead in the rear. If I need more weight I'll add survival gear..........

What engine are you running, Matt? I'm guessing it's a Super Stinson with either the 220 Frank or the 470 Continental. I'm surprised that the engine conversion STC did not relocate the battery in order to at least partially compensate for the heavier powerplant. The O320 conversion for my C150 moved the battery from the firewall to aft of the baggage, and I believe most of the 360 conversions for the C170 do the same.
How much lead ballast are you hauling? Oughta be an easy math exercise to figure what removing the ballast & relocating the battery would do to the CG- don't forget to throw in a little weight for the longer cables. In a case like this, it might be best to stay with a heavy battery - a G25 comes in at around 24 pounds, a G35 at about 29, plus battery box & the longer cables.
Like MTV points out, a forward CG allows for maximum loading-- but then again sometimes a less-forward CG makes for a better handling airplane.

It's a Frank 220, and it's not listed in the STC (nor does it shorten the cowling). I'm pushed up almost to the fwd edge of the envelope with the big piece of ballast back there (it's quite considerable). I'm going to have a little to do list at annual and hopefully drop a good 25-35 lbs. The battery I have now is the 32lb concord, I was sick of the Gill's leaking all over the place.

Thanks for the advice.

I prefer under the seat, easy to get to. For the cold I keep mine in a closed hangar. If I leave her out somewhere I have a battery tender/electric blanket (for around the engine) that I wrap a space blanket around/ and a small space heater that fits width wise perfectly between the rudder pedals and the seat. Got it all at Fred myers for under 100 bucks, keeps the engine warm (even in snow) and the inside really nice.

Darn...now I have to think if I should move my battery while I'm in the rebuild process

Glidergeek wrote:My dilemma is with the Pponk Super Eagle mod I'm doing it's supposed to add 45-50 lbs. that's all up front. I'm changing to the Lite wt. starter and the alternator loosing about 16 lbs with the 2. If I do the battery on the firewall I'll loose an additional what 20-25 lbs? With a net gain of 10-15 lbs but with a even more forward CG. Will 10 lbs in the tail counter the forward CG? And if you answer this today why aren't you out flyin, I've got an excuse

Hi Glider,

IF you can swing it, check out the MT 2 blade prop. It will solve your CG concerns and then some, for just a tad bit more than the 401. It weighs a ton less than the 401. I am doing the O470-50 as well, and if Steve can't get the 88" C66 field approved, I will pony up and do the MT.

Also, I would recommend doing a bit of research on the big engine / light prop, starter adapter issues, prior to going to the light weight starter. I am all about 'light is right' but I may fore go the light weight starter. Remember the Uber light 185 George Mandes built? Here is a guy who wanted to build the lightest 185 that ever flew (and could afford the means to do so) he weighed everything, and if it didn't have merit to the project, it was out... As I recall, the one light weight piece he did not go to was the starter anyways... it might be worth a few quick phone calls..

Take care, Rob

Rob
No I can't justify the $14K+ MT prop, specially seeing as I just acquired a $7k C401 prop -$1K for my C203 traded in. Weighing the pros & cons of the MT vs the McCauly and the Hartzell and finding a 86" C401 for $6K out the door cinched it. I just weighed the C401 and it came in at 71 lbs. I think the MT comes in @ 40 some lbs that would sure help w/the CG but not with the whole cost, but I'm willing to take donations!

Tadpole wrote:Darn...now I have to think if I should move my battery while I'm in the rebuild process

Is yours a super-ized stinson or stock? If it ain't broke, don't fix it...

Glidergeek wrote:ya I agree Burl's lotta $ left over and an STC to boot. Better rethink that price Bill.

Well, I believe there is a reason for the difference in cost. It's my limited understanding that 182STOL's battery box is engineered better, built stronger, and more user-friendly than the STC'd one. Bill has mentioned to me previously that the STC version will not stand up to an "apples to apples" comparison to his "field-approved" design.

The apples to apples comparison would also have to include paying a shop to install them both, because not all owners can do their own work. If 182STOL's unit is easier and faster to install, the difference in installation cost could make up for the purchase price.

EZFlap wrote:.... It's my limited understanding that 182STOL's battery box is engineered better, built stronger, and more user-friendly than the STC'd one. Bill has mentioned to me previously that the STC version will not stand up to an "apples to apples" comparison to his "field-approved" design....

Maybe it's time to get an STC for the mod? I'm sure people would be more eager to buy if they knew they could just have their IA sign off the installation, instead of having to deal with a field approval.
For firewall or flat-on-the-floor installations, Spruce sells a $40 "hold-down bracket" for the Odyssey/Powersafe battery. Nice simple clean installation, bolts through the firewall into nutplates,backing angles, or fender-washered nuts. If I ever move mine to the firewall, that's the way I'll mount it. Battery & bracket are less than $250, throw in some money for hardware & new shorter cables & it still comes up to less than $350 for materials. If the Burl's mount for the C180 is $115 including STC, that sure seems like a good way to go- the whole shitaree oughta add up to not much over $400. Plus installation of course.

Buy an Odyssey battery. NO box required, since the battery is sealed. No vent, etc. Just a bracket to mount the battery.

And, they crank like crazy.

Remember, folks, your EMPTY CG does not have to fall within the airplane's CG envelope. All you really care about is where the CG resides in various LOADED conditions, including of course, where it is in worst case for flight, which is pilot, min fuel and survival gear.

If you can get the plane within the forward limit in that case, you're good.

The Avcon conversion of the Cessna 170 puts a Lycoming O360 in the 170,and it DOES NOT require moving the battery aft. My airplane has the battery on the firewall, and even before I converted to the Odyssey, it was well within the forward limits.

MTV