Anyone tried moving standard equipment for CofG change?

[Awful_Charlie]

Like a few Bravo owners, I've got a couple of charlie weight in the tail to keep the CofG acceptable (only just, two porkers in the front means something is needed in the baggage bay with full fuel).

 

I was wondering if anyone had gone through the process to eg shift one of the batteries aft, or the oxygen cylinder, or something similar, which could then release one of those dead weights in the tail?

 

Sort of guessing at best it is going to be an A&P job, but dreading that it might be into STC or DER territory, which is likely to make is so expensive as to be a non-starter.  I see that the left hand battery box provides a mount for one of the control rods, so that one is unlikely to be practical, but the right one could move.  I've already put as much of the avionics in the tailcone as is practical, and the ELT is right back there too.  Going LED strobes will get the power packs out, but if I do the tail one, that is going to make the problem worse!  Dumping the vacuum system will help a little, but my electric standby pump is also in the tailcone, so the net result is going to be small.  An MT prop would be nice, but that is a sizeable chunk of cash which is going to have to wait until the current one won't pass an overhaul.

 

Any hints or references would be appreciated

 

Ben

[aviatoreb]

The rocket conversion uses two large 35map batteries to correct the balance issue related to the change from a TSIO360 to a TSIO520 up front.

[Jerry 5TJ]

If you upgrade to a G500 you'll remove a surprising amount of weight from the panel, plus the new remote boxes can go in the rear on the avionics shelf.  Less weight total and a more aft distribution, too. 

[Awful_Charlie]

Thanks chaps

The rocket conversion uses two large 35map batteries to correct the balance issue related to the change from a TSIO360 to a TSIO520 up front.

 

The Bravo has the same two batteries in its a$$.  I don't really want to go putting a third one in!

 

 

If you upgrade to a G500 you'll remove a surprising amount of weight from the panel, plus the new remote boxes can go in the rear on the avionics shelf.  Less weight total and a more aft distribution, too. 

 

I've already gone Aspen - that's one small box in the front and one small box in the back (and minus the King gyro and other gubbins - got rid of a few lbs, but the CofG change was negligable)

 

Keep the ideas coming!

[RJBrown]

Where are the Bravo batteries? Rocket put them under and just in front of the leading edge of the stab. Batteries are the only thing heavy enough to make a big change.

[carusoam]

Top of the head ideas...

I also saw the MT as saving a few pounds at a long arm.

Having your O2 system installed in the back ( you probably have this already). Can it be moved???

Going all electric would trade a vac pump for a second alternator...

Going FIKI with the tank and all in the back would add functionallity in place of the charleys..

I saw these ideas when contemplating a new prop for the O1...

The MT STC was not ready when I placed the order. The low mass makes shut down an odd event, visually at least.

As usual, ymmv...

Best regards,

-a-

[scottfromiowa]

Take extra cheese off the pizza...

[Awful_Charlie]

Where are the Bravo batteries? Rocket put them under and just in front of the leading edge of the stab. Batteries are the only thing heavy enough to make a big change.

They're behind the inspection panels, so aft of the avionics.  .  Moving them back was one of the thoughts, but has anyone done this?  Is it just an A&P job, or do I need to get a DER involved or worse?

 

Top of the head ideas...

I also saw the MT as saving a few pounds at a long arm.

Having your O2 system installed in the back ( you probably have this already). Can it be moved???

Yep - the 115CuFt one is in there already.  Moving it back means mounting it on another frame though, the frame it is currently on looks like if may be beefed up for the job though.  Anyone done it?

Going all electric would trade a vac pump for a second alternator...

Bravo has two alternators as standard.  Unfortunately, the Plane Power replacements aren't authorised for the twin alternator installation

Going FIKI with the tank and all in the back would add functionallity in place of the charleys..

Got FIKI already....

I saw these ideas when contemplating a new prop for the O1...

The MT STC was not ready when I placed the order. The low mass makes shut down an odd event, visually at least.

I guess I can handle the few seconds of looking odd at shutdown.  The 10+AMU bill however......

 

As usual, ymmv...

Best regards,

 

-a-

 

 

Take extra cheese off the pizza...

Yeah - fair point - I've not got any lighter over the years.  I call it my investment for when food prices get worse than Avgas.  Maybe it's easier to lose 12lbs off the pilot and move the CofG back a little

[RJBrown]

Investigate how Rocket did it they are on a rack built further back in the tail. There is a row of rivets that you can see on the outside. They hold a shelf back there. Included with the Rocket is a battery board. It is a piece of plywood about 3feet long that is used as a slide to get the batteries in and out.

[N201MKTurbo]

I have a Rocket battery box if anybody wants one.

[carusoam]

I like RJ's recommendation...

The battery placement is challenging to get to where it is, aft of the access panel.

There's always a price for greatness...

I'm surprised That the factory wouldn't offer an option like this on all of the long bodies. Trading challenging battery access for less Charley Weights. I've got 19.7 lbs in there. That's a lot of cheese!

There would be at least one pilot that would get the ingenious idea that flying with a battery removed is a good idea. Having it so far back would increase the out of balance situation. The factory might avoid this situation by not offering what is usable for some and dangerous for others...

Best regards,

-a-

[bd32322]

Where are the charlie weights in the bravo? At the very end in the tailcone ?

On a rocket that was on sale, I saw an extended baggage compartment mod by Lasar. Maybe you could extend the baggage compartment and replace charlies for baggage, unless the charlies are in a very inconvenient spot and not easily swappable for baggage

[carusoam]

From the O POH...

209.5” from the datum, in the tail cone...

Or

17.5 ft from the firewall.

Hat rack is at 131”

Best regards,

-a-

[bd32322]

From the O POH...

209.5” from the datum, in the tail cone...

Or

17.5 ft from the firewall.

Hat rack is at 131”

Best regards,

-a-

 

Ouch - not easily swappable then

Altho no sane FAA person will ever approve swapping weights on the fly - so its a moot point

[yvesg]

Can someone explain to me what is a charlie weigth? I am assuming this is some dead weigth put somehere to properly set the weigth and balance... what is it made of and why is it named this way?

Yves

[carusoam]

What...Lead blocks intended to be swapped out with usefull equipment if so desired...

They maintain the CG in a useable way over time, ( years) and owners ( regions of the world)...

Best regards,

-a-

[Awful_Charlie]

The charlie weights are right at the back of the tail cone, just forward of the bulkhead that the empennage hinge bolts to.  A bit of time with a calculator shows that shifting one battery back three feet has the same effect as removing 6lbs of charlie weight, which in mine, that would mean putting the battery over/just aft of the belly flashing beacon, where it is going to be a right pain to get to, so good to know about the plywood board trick in the Rockets.  I'll have a work with my A&P and see what he thinks.

[CoachTom]

Similar condition in my 231, but I have all three Charlie Weights installed and I have three 25 pound bags of lead shot nestled in the back of the cargo bay.  This gives me full trim capabilities when at lower fuel capacity.  It used to be that when on short final, the electric trim would jam full and I would still not have enough for hands off trim leaving me to push down on the yoke to continue.  After landing, the electric trim would not be able to adjust the trim and I would have to apply pressure with the wheel to "unstick" the trim.

 

With the added aft weight, I have authority now and the lead shot bags take up minimum space.