EarthX CG Change

[JACK]

We're considering installing a EarthX battery and mounting it to the tubes by the firewall. I'd like to be able to figure the correct w&b change. Can anyone give me the arm I'd use to figure the new battery location?

 

[belloypilot]

I have a 99 A-1B. Looking through AFM equipment list it shows the factory battery location arm as 144”. I’m also about to take some float training in 2007 A-1C 200 so I have that AFM as well and it shows the battery arm as the same 144”.

 

[JACK]

Yeah, thanks, I have the current battery arm. I need to know the new arm if I attach it to the tubes by the firewall under the instrument panel.

 

[belloypilot]

Looking at other arm locations on the equipment list it would appear to be in the 36-38” range, but my guesses are likely not what you’re looking for. I have a similar project coming up and haven’t decided if I’ll put the EarthX in the existing battery location or firewall mount it. It will be based on what it does to the empty CG so I’ll be interested what you decide and why. Chances are I’ll keep mine in the original location.

 

[johnaz]

Looking at other arm locations on the equipment list it would appear to be in the 36-38” range, but my guesses are likely not what you’re looking for. I have a similar project coming up and haven’t decided if I’ll put the EarthX in the existing battery location or firewall mount it. It will be based on what it does to the empty CG so I’ll be interested what you decide and why. Chances are I’ll keep mine in the original location.

Mike,
As the Husky's are normally pretty nose heavy, unless building a really light one it may be best to keep batt in back. Just lose weight with the EarthX. Or one could lose a bit more without the long cable runs, so lighter all around is always better.
Hope your float training is fun. Your floats will be ready.
John

 

[belloypilot]

Mike,
As the Husky's are normally pretty nose heavy, unless building a really light one it may be best to keep batt in back. Just lose weight with the EarthX. Or one could lose a bit more without the long cable runs, so lighter all around is always better.
Hope your float training is fun. Your floats will be ready.
John

Thanks, John. Those were my thoughts on battery location as well. I got the float rating done back in November. Headed to Havasu tomorrow to get some time in an amphib Husky and planning on a bit more Husky amphib dual time in Canada later this spring. I checked in with Starr and currently thinking mid July to get up to Anchorage. Looking forward to it .

 

[JACK]

We have the MT propeller so that moved our CG rearward. That's the reason we want to go with the firewall mount.
I found a copy of an equipment list showing the vacuum filter at 32 inches. And the picture with that airplane shows the filter attached directly to the firewall. If I attach to the tubes next to the firewall I will probably use 33 inches unless I find something different.

 

[belloypilot]

We have the MT propeller so that moved our CG rearward. That's the reason we want to go with the firewall mount.
I found a copy of an equipment list showing the vacuum filter at 32 inches. And the picture with that airplane shows the filter attached directly to the firewall. If I attach to the tubes next to the firewall I will probably use 33 inches unless I find something different.

I have an MT Ultra as well. My empty CG is at 73.5 on 31" bushwheels and I'm pretty happy with it there. I've never had trouble running out of aft envelope. I was actually more concerned about shifting CG forward with the EarthX STC.

 

[JACK]

If I recall I figured the CG shift both ways. Leaving the EarthX in the original position moved the CG about .9 inches, and moving it to the firewall moved it about 1.4 inches. We have a Concorde RG 25XC battery right now.

I have a copy of a 337 that another forum member used when he moved his battery to the firewall. I haven’t approached our IA yet. I’m still gathering information and trying to decide if we want to go the firewall route.