Posted for "Craig Berland" <cberland@systems3.net>:
Rick,
Your questions are prudent and on target. With that said, I don't have
a lot of answers. Here is what I have done and what I am doing. I
built most of the airplane myself here is Arizona. I am a mechanical
engineer with no false conception of thinking I understand electronics.
Electrical/mechanical devices...yes, electronics....no. Therefore, I
have chosen the following path. Aerotronics in Billings, MT has built
my panel and I followed there guidance on wiring practices. The panel
is complete and was to ship yesterday but it did not clear testing
Monday. Therefore it will test next Monday and ship early next week.
On the aircraft build side, I moved the airplane to Palomar Airport in
California and Ron Gregory is helping me complete it. Ron has an
avionics expert. That was one of the big factors in my decision to get
help finishing. Once the aircraft wiring process starts, I will have a
lot more honest answers.
Here is what I've done and what I believe to be true.
0. Lancair once used two 24 pin connectors and now uses two 32 pin.
They must be needed. ?? Yes, they are all the same size.
1. Relays inside of the cabin = good plan
2. Thermal couples - don't use 32 pin connectors. Must maintain TC
material for calibration and reliability.
3. Pressure transducer wires, lights, etc use 32 pin
4. You can get an "altitude" module for the MVP-50 and set parameters
to give an oral warning to check low boost fuel pump on/off going
through 10,000 ft. (food for thought)
5. I did not yet install the 32 pin connectors and the (4) pass-through
compression sleeves marked for thermal couple, etc. My reasoning
was....I can wait until the panel shows up and wiring commences and not
hurt anything. On major projects like this, I like to leave myself
options if I can. I find that the learning process is steep and leaving
options is always best.
6. Voltage regulators need to sense battery temp. If you are using B&C
with temp sensor, then OK and good inside.
7. Could use a prop heat relay on engine side if necessary. I do not
know what the 32 pin connector current limit is. I will have to find
out as well. I have a 28V system....that helps a lot. One half the
current draw of a 14V system. I suspect the connectors will work. I
have MT low current draw boots.
8. I would leave the MVP data boxes in the cabin.
(remember..."mechanical engineer")
9. I built my own carbon battery box and laid the battery against the
firewall.
I did do an electrical system failure analysis and then made a minor
change to the Aerotronics wiring scheme. As it appears you are...I am a
total electric airplane with A/C and prop de-ice.
The entire Lancair firewall forward plans for the IV-P are of little
use. Most stuff has changed. While it took lots of research to find out
what was best, I'm glad I did my own thing. Relays inside the cabin,
laid back battery box and no gascolator are the main reasons. Otherwise
what I have done so far is just like what Lancair is doing if you buy
their firewall forward. It is not much like the kit plans.
Hope this helps.
Craig
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