[Webb]

As I look at the potential W&B for my 8, it looks like the CG is going to be forward. Instead of adding ballast in the the rear seat or baggage compartment for a single pilot, I am thinking of a few pounds of lead weight bolted to the aft fuselage deck.

Has anyone done that instead of adding a lot more weight to the more forward areas?

 

[catmandu]

Yes.

With a Super-8, the builder put what looks to be 10 lbs of lead there. Even then, I discovered after I bought the plane that I ran out of nose up trim as I slowed on final when solo. Not scary, but not what I wanted. I have removed firewall forward weight, turned one aft mounted concord battery into two PC925’S, and still I have to put my traveling tool bag, etc. on the upper rear baggage shelf when solo. I just accept an overalll heavy airplane to make solo landing a climbing beast more palatable.

Next up: a prop change.

 

[Mikeyb]

As I look at the potential W&B for my 8, it looks like the CG is going to be forward. Instead of adding ballast in the the rear seat or baggage compartment for a single pilot, I am thinking of a few pounds of lead weight bolted to the aft fuselage deck.

Has anyone done that instead of adding a lot more weight to the more forward areas?

This is the holy grail of removable tail weight. I saw another variant that used a slug of lead that slid in from the side. I’m going to figure out a way to do it. My -8 at an 82” CG doesn’t really spin. The stick force in pitch is obnoxious.

Optimizing Center of Gravity for Aerobatics

Did you ever wonder why two-seat aerobatic airplanes like the Extra 330LX, the Pitts S2 or the Decathlon are flown solo from the rear seat? It’s all about managing the center of gravity (CG) for optimum aerobatic performance. Since the passenger seats in the above examples are located almost...

vansairforce.net

 

[Webb]

This is the holy grail of removable tail weight. I saw another variant that used a slug of lead that slid in from the side. I’m going to figure out a way to do it. My -8 at an 82” CG doesn’t really spin. The stick force in pitch is obnoxious.

Very ingenious way of adding ballast. I don't have a W&B yet but I used info from a POH that is setup like mine will be. Initial calculations puts my test pilot out of the envelope (fwd side) unless he has more than 1/2 full tanks. I have some lead bar counterweights that total 7.3 lbs that can be bolted to the empennage deck which puts him in the envelope even with empty tanks.

I outweigh the test pilot who is also my flying buddy by about 70 pounds. Even with me in the rear seat, we are still in the envelope with spare to go for baggage with the extra ballast.

I thought about something removable but it seems to me that if 7 pounds keeps the CG in the envelope at all times, it makes sense to install and leave it there.

Granted this is hypothetical until I can get my W&B, it's supposition. Who knows, I might not even need to add any ballast.

 

[Ironflight]

Very ingenious way of adding ballast. I don't have a W&B yet but I used info from a POH that is setup like mine will be. Initial calculations puts my test pilot out of the envelope (fwd side) unless he has more than 1/2 full tanks. I have some lead bar counterweights that total 7.3 lbs that can be bolted to the empennage deck which puts him in the envelope even with empty tanks.

I outweigh the test pilot who is also my flying buddy by about 70 pounds. Even with me in the rear seat, we are still in the envelope with spare to go for baggage with the extra ballast.

I thought about something removable but it seems to me that if 7 pounds keeps the CG in the envelope at all times, it makes sense to install and leave it there.

Granted this is hypothetical until I can get my W&B, it's supposition. Who knows, I might not even need to add any ballast.

Just be very careful sneaking up on aft CG’s in the -8 Webb….many people go ”fly the same hour 40 times”, sign the airplane out of Phase 1, throw a buddy in the back seat and head to the nearest pancake breakfast to celebrate. They smash the tail on the ground the first landing, in front of the crowds because they didn’t understand that the handling qualities are very, very different at aft CG in an -8. You need to push forward as it slows down in the flair to keep the nose from coming up at a brisk rate.

Bottom line - I won’t carry anyone more than 220 in the rear seat of my standard -8 with an O-360 and C/S prop.

 

[Carl Froehlich]

Bottom line - I won’t carry anyone more than 220 in the rear seat of my standard -8 with an O-360 and C/S prop.

Even though my W&B supports a 220 pound bubba in the back, my level of tolerance is 180 pounds of passenger and passenger luggage. I am after all an amateur pilot…..

Carl

 

[Webb]

Just be very careful sneaking up on aft CG’s in the -8 Webb….many people go ”fly the same hour 40 times”, sign the airplane out of Phase 1, throw a buddy in the back seat and head to the nearest pancake breakfast to celebrate. They smash the tail on the ground the first landing, in front of the crowds because they didn’t understand that the handling qualities are very, very different at aft CG in an -8. You need to push forward as it slows down in the flair to keep the nose from coming up at a brisk rate.

Bottom line - I won’t carry anyone more than 220 in the rear seat of my standard -8 with an O-360 and C/S prop.

Thanks Paul. Granted these are just a guesstimate. Two sets are with my friend as test pilot alone. 2 of them are him in front and me in the rear. He is 175, I’m 245 with the fat boy in back (me). Each pair is with and without ballast of 7.3 lbs in the tail section. If I’m in the front seat and he is rear, it‘s close to center CG. As you can tell, ballistic will be needed when he is by himself.

You do bring up a good point. Perhaps it would be best to have a removable weight for the back seat for when he is solo. If it’s me solo, added ballast won’t be needed. Sounds like a case of water me be just the ticket.

Of course I won’t know until I get an actual W&B. It’s just a good exercise for now.

 

[YellaDawg]

I have a lot of weight up front, an aerobatic Hartzell C/S prop, IO 390 EXP 119, polished Aluminum Spinner and a 3" extension with Showplanes Cowl, so I knew was going to be nose heavy. I did put two lead ingots on the rear flight deck that are removable (I used nut plates, and AN4 bolts and a steel doubler) I am within CG limits without them, but barely, and do run out of trim solo, nothing in the back and minimum fuel. I also am in CG with them and a full load in the passenger and baggage compartment, always a tool kit in the baggage compartment as well. just have to manage it. I'll take them out going to Oshkosh loaded with camping gear.