Online Community of Zenith Builders and Flyers
Hey there. I owned a 601HD (that someone else built) a few years back. Now I want to build my own 750 Cruzer. As I was watching one of Mike Patey's videos, I saw that he is using shielded wire to eliminate EFI, etc. So my question as a first time builder thinking about how to design my perfect plane, do you guys know of good resources that can expose me to the ideas of what I might want to add/upgrade/change/delete on my own plane? Some things are obvious like single-stick vs dual sticks, choosing a panel layout, etc. However, some of these ideas, like shielded wires, I wouldn't probably have ever thought of until it was too late. I have less than 100 hours in the air as well, so I just don't have the street smarts to know all of the things I might want either.
For electrical help try http://www.aeroelectric.com/
See this post on this forum that references the builder's modifications in the linked video.
More general resources;
Tony Bingelis' books on construction (Amazon, ACS, EAA, etc.) as well AC-43-13-1... Acceptable Methods (google -- you can download online), as well as the weekly HomebuiltHelp on YouTube -- I also have most of his other DVDs and they are helpful, not necessarily for modifications, but just how to do the basics...
A piece of general advice -- it is very easy to add weight to a plane, it is very hard to add lightness to a plane. Consider every little extra bracket or piece of wire shielding or added "beef" not called for in the plans very carefully. Each little thing is just that, little. However, over the course of the build it is very easy to add a lot of pork to your little piggy.
As far as shielded wire goes, it is not needed for most uses in the plane. There are a few circuits where it can be helpful but using shielded wire in the whole plane just because you can will add a pound or two to your build (the shielding is braided metal, after all). Sources like the Aeroelectric Connection can help you decide where to use shielded and where to not bother. The same thoughts apply to wire size choices -- if the charts say 22 gage wire will work for a circuit but you use 18 gage wire because you want to be extra sure, you have just added more weight to the build. More robust wires add weight. If you calculate that your electric system will need 20 amps of generating power to be adequate but you find a good deal on a 40 amp alternator and use it, you just added several pounds over the weight of using an alternator sized to your needs. It is soooo easy to add needless weight to a build one tiny bit at a time but given the thousands of parts involved it adds up.
A final thought -- some added lightness can be purchased. A good example is the main landing gear. I am gonna build a 601XLB so I am familiiar with that plane's components but I suspect the same example would work for a 750. The stock Zenith main gear assembly is made of 6061T6 and is sized to make that part made of that alloy strong enough to stand up to being a landing gear. The Grove main landing gear assembly weighs about 15 pounds less (!) than the stock Zenith gear because it's made of a stronger alloy that can use less metal to provide the same strength as the Zenith part. It also costs a lot more becuase it's a more expensive alloy and requires heat treatment processing during manufacture, but saving 15 pounds on your build is HUGE. Other places where weight is easy to gain or lose is engine and propeller choice. There is also the level of finish choice - a thick heavy high gloss paint job weighs more than a thin but less elegant paint job or bare metal, a full interior with insulation and interior trim panels and full leather upholstery will add lots of weight compared to a bare bones interior with none of those things and just enough seat cushions to make you comfortable. You get the idea.
I'm fully with you Bob. Thanks for the advice.
Ditto Bob's remarks!
I love to do mods and as Bob points out, most result in weight gain and reduced useful load! I had added about 12 lbs of gross weight to my STOL 750 due to a tubular steel 4-point harness mount and 2 A/P servos. I purchased and "erased" that weight gain by switching from an Odyssey PC680 (great battery but heavy!) to an EarthX ETX680 which was 11 lbs lighter. As a bonus, the EarthX has a higher resting voltage and lower internal resistance so it spins the Jab3300 much faster and I get reliable starts at any temperature. Normally, you can't count the blades it starts so quick! "Lightness" was not cheap, but worth it. BTW, 7 years later, the Odyssey is still reliably chugging away in one of my lawn tractors! :>)
Some great replies here. Thanks alot!