My 170 B was nose heavy, I dont like to fly a nose heavy airplane, so added 70 pounds of weight in the cargo area, now CG is balanced just in the center and flies nicely.

I dont want to keep the 70 pounds, maybe just 20 or 30 of survival gear, and rather put ballast on the tail to keep the CG where it is or maybe a bit more aft.

My first question, is it legal? my mechanic is not too sure.
Where is the best location to add ballast on the 170, and who ever have done it how do you secure it.

I know some pilots dont like to add ballast, we added 17 pounds of lead in the tail of my 182 and did make a big difference,

Yes, it is legal to install ballast to maintain CG.

That said, there is no way I would do so! Note the exclamation mark…..

Instead, if you haven’t already, install an extended baggage. Then secure a survival pack at the aft end of it. Landing the places you do, a survival kit is an essential, in my opinion. So, it needs to be there at all times.

BUT, now, when you need to carry a big load somewhere, you’ll have your full useful load.

Install permanent ballast, and you’ve reduced permanently your useful load.

I have always argued against permanent ballast to achieve a “happy” empty CG. Because it seems we should always be carrying some “useful” ballast, in my opinion.

Years ago, I checked out in an amphib Beaver. Our mechanics didn’t like the CG, which was forward. The crusty old Check Airman got in a heated conversation with the mechanics, who wanted to install permanent ballast. He won, and I never once regretted that.

If a small survival kit all the way aft isn’t enough, make up a small tool kit, and cure that all the way aft. But, PLEASE don’t install permanent ballast in that gorgeous plane!

MTV

Wise words MTV, keep an airframe as light as possible and thereby retain "all option" as required as per mission.

I cannot install an extended baggage compartment because the battery its in that area, I dont want to move the battery to the firewall because its what I am trying to avoid, more weight on the front, and if I move it to the front, more weight will be needed at the extended baggage compartment.

Now can the battery be moved more towards the rear ? This could solve the problem.
Right now it is right behind the lid of the cargo area.

motoadve wrote:I cannot install an extended baggage compartment because the battery its in that area, I dont want to move the battery to the firewall because its what I am trying to avoid, more weight on the front, and if I move it to the front, more weight will be needed at the extended baggage compartment.

Now can the battery be moved more towards the rear ? This could solve the problem.
Right now it is right behind the lid of the cargo area.

What size/weight of battery is your current battery. Some of the newer batteries are reasonable light so placing it on the firewall along with the weight reduction in wiring length required may be a net gain. the lighter forward battery is then easily offset by the options an extended baggage are will offer you for "load control".

I am in the same spot. I went with an Atleedodge firewall battery and am just now installing an Airglas extended bagage. I’ll be putting my survival gear, spare tubes and tools back there.

Definitely flares differently with a forward cg but the performance of the O-360 is worth it for me.

An MT prop would help but I am spent out for now.

Motoadve, what year is your 170? The 52 I had came with a battery mounted on the firewall. I replaced that lead ballast with a smaller, Odyssey battery in the same box.

But, if your battery is already aft, why not install an extended baggage, replace existing battery with a (presumably smaller) Odyssey, laid on it's side, mounted BELOW the aft baggage, and accessable via a hinged door?

I'm pretty sure an Odyssey would lay on its side under a Selkirk extended baggage. Maybe.

Otherwise, install the extended baggage, then mount a battery box (with small battery) IN that extended baggage.

But, in my case, with this 175, with the big battery mounted aft, I removed it, replaced it with a firewall mounted Odyssey battery, and never looked back. I always fly with survival gear aft in any case, so CG works fine for me.

I HATE aft mounted batteries. Too long cables, and hard to get to. But, if you're REALLY that worried about CG.....keep it back there and change to an Odyssey, with ext. baggage.

MTV

One other thought: Who weighed the plane, and calculated the W/B? Are you confident that it is accurate? A 170 with a composite prop shouldn't be that far forward CG with an aft battery, seems to me.

Was the plane put on certified scales after rebuild, or was W/B calculated? If calculated, I'd get it weighed by a reputable shop, on certified scales, and see if everything jives.

I MUCH prefer an empty plane that is somewhat forward, because I carry stuff in my planes. And, ALL that stuff moves the CG aft.

MTV

mtv wrote:Motoadve, what year is your 170? The 52 I had came with a battery mounted on the firewall. I replaced that lead ballast with a smaller, Odyssey battery in the same box.

But, if your battery is already aft, why not install an extended baggage, replace existing battery with a (presumably smaller) Odyssey, laid on it's side, mounted BELOW the aft baggage, and accessable via a hinged door?

I'm pretty sure an Odyssey would lay on its side under a Selkirk extended baggage. Maybe.

Otherwise, install the extended baggage, then mount a battery box (with small battery) IN that extended baggage.

But, in my case, with this 175, with the big battery mounted aft, I removed it, replaced it with a firewall mounted Odyssey battery, and never looked back. I always fly with survival gear aft in any case, so CG works fine for me.

I HATE aft mounted batteries. Too long cables, and hard to get to. But, if you're REALLY that worried about CG.....keep it back there and change to an Odyssey, with ext. baggage.

MTV

But, if your battery is already aft, why not install an extended baggage, replace existing battery with a (presumably smaller) Odyssey, laid on it's side, mounted BELOW the aft baggage, and accessable via a hinged door?

I like this idea.

Just remember you heard it here first on BCP

motoadve wrote:

mtv wrote:Motoadve, what year is your 170? The 52 I had came with a battery mounted on the firewall. I replaced that lead ballast with a smaller, Odyssey battery in the same box.

But, if your battery is already aft, why not install an extended baggage, replace existing battery with a (presumably smaller) Odyssey, laid on it's side, mounted BELOW the aft baggage, and accessable via a hinged door?

I'm pretty sure an Odyssey would lay on its side under a Selkirk extended baggage. Maybe.

Otherwise, install the extended baggage, then mount a battery box (with small battery) IN that extended baggage.

But, in my case, with this 175, with the big battery mounted aft, I removed it, replaced it with a firewall mounted Odyssey battery, and never looked back. I always fly with survival gear aft in any case, so CG works fine for me.

I HATE aft mounted batteries. Too long cables, and hard to get to. But, if you're REALLY that worried about CG.....keep it back there and change to an Odyssey, with ext. baggage.

MTV

But, if your battery is already aft, why not install an extended baggage, replace existing battery with a (presumably smaller) Odyssey, laid on it's side, mounted BELOW the aft baggage, and accessable via a hinged door?

I like this idea.

Just remember you heard it here first on BCP.

And, in case anyone is windering, the Odyssey battery is a “recombinant gas mat battery” whatever that means……but point is: It’s a sealed battery, so requires no battery box, and can be mounted in any position.

Here's what a buddy of mine did in his 180.
Battery is right under the pilot's seat,
pretty close to the empty CG of the airplane.
Not sure what he did re paperwork,
I suspect it was a field approval.

Firewall-mounted batteries & flat-floored extended baggage compartments are relatively new developments. I'm pretty sure that raised-floor extended baggage kits are available for the 170 that allow the battery to stay in that aft position. I've sure seen plenty of 180s set up that way.
I'm guessing you have a 25 size battery in that 170, you might switch to a 35 to add a little weight aft -- and more cranking amps and/or amp-hours to boot.

What 3 blade MT prop do you run on the O-360 on the 170B?

MW

hotrod180 wrote:Firewall-mounted batteries & flat-floored extended baggage compartments are relatively new developments. I'm pretty sure that raised-floor extended baggage kits are available for the 170 that allow the battery to stay in that aft position. I've sure seen plenty of 180s set up that way.
I'm guessing you have a 25 size battery in that 170, you might switch to a 35 to add a little weight aft -- and more cranking amps and/or amp-hours to boot.

The only extended baggage kits I've seen for the 170 have a floor that extends at same level as the main baggage. But, as I noted, my old 170 was a 52, and those airplanes had the battery on the firewall stock. Which I much preferred, since airplane was in Alaska, and parked outside. Pre-heat warmed the battery as well as the engine.

I HATE batteries aft....which is why I put an Odyssey on the firewall of my 175.

Carry some stuff aft that you're always wanting to have along anyway.

Do you not carry basic survival gear EVERY time you fly? If not, you have a lot more trust in little airplanes, engines and weather than I consider wise. And, a small tool kit helps as well.

MTV

mtv wrote:

hotrod180 wrote:Firewall-mounted batteries & flat-floored extended baggage compartments are relatively new developments. I'm pretty sure that raised-floor extended baggage kits are available for the 170 that allow the battery to stay in that aft position. I've sure seen plenty of 180s set up that way.
I'm guessing you have a 25 size battery in that 170, you might switch to a 35 to add a little weight aft -- and more cranking amps and/or amp-hours to boot.

The only extended baggage kits I've seen for the 170 have a floor that extends at same level as the main baggage. But, as I noted, my old 170 was a 52, and those airplanes had the battery on the firewall stock. Which I much preferred, since airplane was in Alaska, and parked outside. Pre-heat warmed the battery as well as the engine.

I HATE batteries aft....which is why I put an Odyssey on the firewall of my 175.

Carry some stuff aft that you're always wanting to have along anyway.

Do you not carry basic survival gear EVERY time you fly? If not, you have a lot more trust in little airplanes, engines and weather than I consider wise. And, a small tool kit helps as well.

MTV

I carry 20 pounds of survival gear plus 50 pounds of ballast in the cargo area.
The CG is pretty nice to the center and just a bit aft.
I hate to carry 50 pounds of ballast though, talked to an FAA guy , he told me I can install an extended baggage compartment and move the battery behind that compartment, a field approval should not be a problem.
This will probably allows me to get rid of 50 pounds of ballast in the cargo area.

mtv wrote:Yes, it is legal to install ballast to maintain CG.

That said, there is no way I would do so! Note the exclamation mark…..

MTV

Larry,


I have a similar problem in my 180 but have an extended baggage compartment and 50 lbs in the back fixes the problem. I understand Mike's quote here in that installation of permanent ballast reducing the total UL and being very difficult to remove but have also wondered just for a convenience to add 5 lbs to the stinger with some weights to make the cg more permanently aft. I believe it can be done with a field approval. I would have to do the math but I believe 5 lbs on the stinger would have a fairly dramatic effect on cg. You could move the battery to the firewall and save weight going with the odyssey. Is a 5 lb loss in UL worth the positive effects on cg? Don't know ? I keep a tent, sleeping bag, first aid, basic tools, water, rations, and survival gear in the aft compartment. It adds up to 50 lbs. Occasionally - I load the plane up with 3-4 people and need to move things around in that compartment - made me think about this very question. It is not that big of a deal and I am not likely to change anything in my C180 but it is food for thought. I have mostly tried to reduce the weight of my plane in every possible way - so the idea of adding weight goes against my basic premise of less is more.


Josh

My shitbox (maule) has a removable ballast in the tail, where there is a tube that it is secured to/in. There is an identical tube under the pilot's seat (nearly directly below CG). If flying around empty as most people do, keep the ballast in the tail. When loading up, remove the ballast or move it under pilot's seat to eliminate it's effects on CG. Seems like a decent system.

The black loop is the handle on top of the ballast weight, which feels like a piece of steel that's covered in a cast rubber or epoxy type material. There is a thumbscrew used to keep it from departing the tube.

asa wrote:My shitbox (maule) has a removable ballast in the tail, where there is a tube that it is secured to/in. There is an identical tube under the pilot's seat (nearly directly below CG). If flying around empty as most people do, keep the ballast in the tail. When loading up, remove the ballast or move it under pilot's seat to eliminate it's effects on CG. Seems like a decent system.

The black loop is the handle on top of the ballast weight, which feels like a piece of steel that's covered in a cast rubber or epoxy type material. There is a thumbscrew used to keep it from departing the tube.

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I always wondered what that little tube was for...