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From: "Janie & Ed Smith" <2luv2fly@cox.net>
Sunday Evening
6/15/03
Jim Hergert,
Did the Aero Cool system affect your CG much one way or the other? Any changes made on the way you load the airplane?
Any "hindsight" that you could pass on to those of use who are still building as far as the installation??
Thanks,
Ed Smith
Chesapeake, VA
Hi Ed,
I really don't know how the AC affected my CG because I built the airplane with it in. Maybe someone who has added it and weighed the airplane before and after could answer that better. Using Mike C.'s weight numbers we were very comfortable with the balance of the different weight units. Engine compressor just behind the prop, 15 lbs. The evaporator on the rear pressure bulkhead, very close to the CG, additionally we had to make a cover with upholstery to go over it. Then you get to the aft fuselage condensor/fan and ducts, which I thought weighed maybe 3 or 4 lbs more than the compensator, that your eliminate with Mike's modification that eliminates all the Bellows. Note; no future leaks or repairs.
My airplane is in the aft CG range and most of that was from putting that 10 lbs TCAD 9900BX in the tail along with the Stormscope stuff and the Yaw damper servo 3 lbs way in the back tail, AND, a big AND, is the MT 4 blade prop up front. It is about 40 lbs lighter than the new 3 blade Hartzell with the full feathering. That prop is 7 to 10 kts. faster but I think but mine is prettier. I'm already very heavy, so I don't want to add the prop weight. I do try to load most of the heavy things forward. Like I have a tool kit that I put behind the front seat if I have a load, otherwise it is in the baggage area. Also, I have a heavy survival pack that I am currently trying to make the big decision as to whether to have it? or put it into smaller packs and Velcro them to the rear of the firewall in front of the rudder pedals on the right side. Kind of makes since there. I also upholstered my baggage compartment which is weight you could leave out. So far the aft CG hasn't caused any problem and I am planing now to do a serious stall test or approach to stall test with a very experienced L4 test pilot in the right seat. I have stalled two other L4's with no problem but still need to get my stall number to put into the SFS so it's stall warnings can be believed.
In "Hindsight" I wouldn't change a thing. We knew that everything that could be put forward would be better CG wise, but you have to decide what trade off to make. Like Charlie K. I had a hard time deciding whether to spend $20K on the TCAD then the weight but I tell you now I love it, almost as much as the AC.
We just flew form San Jose to Sedona at FL 230, the AC was on all the way up to 230, then turned off with just the cabin blower running. Then on decent at 14K it started to warm up, turned it on and it was on until shut down. My wife said "Boy do I love that AC, how could you get by without it." That is after you open the door and the heat hits you.
Bottom-line, you will be looking into AC after you get flying unless you live in a cold area.
Jim Hergert
N6XE, "An Sex Y" L4P
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