- Joined
- May 23, 2010
- Messages
- 119
- Reaction score
- 33
My Acro Sport II empty weight CG is only 4 inches forward of the leading edge of the lower wing and this means with a passenger and minimum fuel my CG is slightly aft of the rear CG limits used with the prototype Acro Sport II. (I have heard that some other Acro Sport IIs have a rear limit that is up to 7 inches aft of the leading edge of the lower wing, but I have been using 5 inches aft as the standard.)
I have been flying my airplane for 600+ hours over 24 years without any problems, but I only do occasional mild aerobatics and rarely take a passenger.Now that I am retired I have a little more time and have considered making new cowlings as the originals have a few cracks in the corners that I have had to repair over the years. Since I may make new cowls, I wondered how much moving the engine and prop forward one inch might help my rear CG calculations.
I thought it would be easy enough to make metal spacers on a lathe and use longer motor mount bolts to mount my existing motor mount forward one inch from the firewall.
Question - I don't know how to calculate what impact moving the engine/prop forward one inch might have on my current CG. Moving the engine and prop one inch forward also changes the arm lengths for my CG calculations since I use the front of the prop face for my datum point.
My airplane empty weight is only 911 pounds (150 Lyc, no inverted, McCauley Metal Prop, battery under fuel tank), but I have almost 80 pounds of the empty weight on the tailwheel when the airplane is level.
The airplane flys fine as it is, but I would like a little more safety to carry a heavier passenger without full fuel.
Anyone have any thoughts about this type of change? I would like some idea of the actual change to the CG before I go ahead with the work.
Thanks, Steve
I have been flying my airplane for 600+ hours over 24 years without any problems, but I only do occasional mild aerobatics and rarely take a passenger.Now that I am retired I have a little more time and have considered making new cowlings as the originals have a few cracks in the corners that I have had to repair over the years. Since I may make new cowls, I wondered how much moving the engine and prop forward one inch might help my rear CG calculations.
I thought it would be easy enough to make metal spacers on a lathe and use longer motor mount bolts to mount my existing motor mount forward one inch from the firewall.
Question - I don't know how to calculate what impact moving the engine/prop forward one inch might have on my current CG. Moving the engine and prop one inch forward also changes the arm lengths for my CG calculations since I use the front of the prop face for my datum point.
My airplane empty weight is only 911 pounds (150 Lyc, no inverted, McCauley Metal Prop, battery under fuel tank), but I have almost 80 pounds of the empty weight on the tailwheel when the airplane is level.
The airplane flys fine as it is, but I would like a little more safety to carry a heavier passenger without full fuel.
Anyone have any thoughts about this type of change? I would like some idea of the actual change to the CG before I go ahead with the work.
Thanks, Steve
