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Zenith CH750 build...

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Taiser

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HI!

I've had some interest in my build on other forums. I figure if I put the details on here I can point people to this thread and generate some new traffic ;) and I figure it's a good place to keep a good track record of my build. Made some mistakes (minor) along the way and maybe this will keep some people for doing the same thing.

Why a CH750?

I've wanted to build a plane for a looonnnnngggg time, since I was 15 actually when I read a Kitplanes magazine that had a "Windwagon" article in it. Basically a modified Hummelbird. Had the flying bug since then... I got my license to fly at 16 and then became an AME after college. Left the aviation business when I got tired of working in the bush on planes and jobs in the aviation field were drying up big time at that time. Went back to school into a different field. Things got in way, as they always do. Work, got married, kid, houses, cars and next thing you know building became a distant memory...still there mind you, just not pressing.

A few years ago, after thinking about it for YEARS I took the plunge! :grin: I ordered a set of H5 plans from Hummel Aviation. I looked them over and really love that plane, BUT I decided I wanted a two seater. Since "Low and Slow" is the way I like it and I've always been a fan of the Zenith STOLS, I bit the bullet and ordered a 750 Kit from Zenair! :ban: I still have the H5 plans. I've been having a great time building and once the 750 is done I plan on building the H5 as a BULA just for a fun flyer. Probably start that in a few years...


How is the build going?

I started building at Christmas of 2011. As it stands now it's on it's gear with the engine mounted. The tail is done, the wings are done. I'm currently running fuel lines and electrical work. I'm hoping for a pre-cover inspection to be done by MD-RA this fall.

Overall it's an impressive kit! Had a few issues but nothing major. Zenair is only a phone call away and always has answers. Got a few parts that were not right and they were replaced right away. The kit is "match drilled" for the most part so basically you cleco the parts together, enlarge the holes and rivet them together...well a little more involved than that, but basically that's as simple as it is!

What's it going to have?

After the flight testing is done I'm putting amphibious floats on it. Going with a MGL or Dynon glass panel. The engine is a O-235 putting out 115 hp. Vortex generators on the elevator. Went for the dual stick option, not crazy about the center "Y" stick the plane comes from, although I hear good things about it.

PICTURES?

I'll start putting pictures below from the build along with pertinent information! :zzz: Might take a bit before I get them all on...

So here we go...
 
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Taiser

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Messages
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Location
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So here's what happens when you order a kit! First it takes about two months after your deposit to receive. Then when it's ready to be shipped you get this sad looking thing called a "bill" and cry for a while! :)


Then about a week after that a big-ass truck shows up at your house....





Then you thank god you own a small tractor to unload this HUGE crate, one crate of two mind you and try to get it off the truck without wrecking the thing. This was delivered a few days before Christmas...






Then you manage to get it into your garage and realize just how big this #$%^&* box is!!!!






..and then you open the box and get a look at just what you got yourself into! :)
 

Taiser

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Messages
1,154
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So now comes the fun time of inventorying all the parts and comparing them to the invoice. Also checking for damage. The only damage I had was a small ding on one of the skins, easily fixed and I was missing a castle nut and the flap motor. A quick call to Zen and the parts were shipped up within a day! Can't complain about that!



Minor ding on skin. Paper was ripped when I got it...
 

Taiser

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So I decided to start on the fuselage first. Seemed pretty straight forward and I was anxious to sit in the cockpit and start making airplane sounds... Plus I figured it would get rid of a lot of the biggest parts and skins from laying around and possibly getting damaged.






This is the bottom skin. The large hole is an access in the belly. You start by laying out the longerons on the sides. The longerons are pretty fancy extruded aluminum pieces. Once on they form a nice smooth curve to each side of the skins. You have to clamp them on then drill through the pre-drilled holes in the skins and cleco them together. The channel in the center gets installed later, I put it on to stiffen the skin temporarily...





Then the "L" angles go on. They are simple 90 degree pieces of aluminum and simply stiffen the fuselage tail. Mostly used to stop "oil canning" of the skin. Works pretty well. Again clamped on and drilled via pre-drilled holes on the skin. Have to do it on you back though, easiest way but a bit of a pain. The access hole has a "Z" angle around it, little more stiff than a standard "L".
 

Taiser

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...and here's the view from the bottom of the skin with all the clecos in holding the longerons on...
 

Taiser

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So once the parts are all drilled out to final size they are taken all apart (a depressing time) then all the holes are deburred and, if you want (and I think it's absolutely necessary though some people don't) you can add the corrosion protection. I used both Zinc Chromate and Zinc Oxide on the matting surfaces. Once dry and reassemble all the parts (Yay) and that classic moment...........the FIRST rivet gets put in.....



Historic moment #1. The FIRST Rivet I put in the build! :D
 

Taiser

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So now the side skins get worked on. They are a little more unweildy because of all the cut outs for the windows and such. You also have to be super careful with the longeron alignment because they have to match from side to bottom and top so they have to be temporarily all set up so you can drill holes in the right areas. The small bulkheads in the back is where the tail attaches so it needs extra beef! Diagonal "L"s are used on the side skins as well.



Floppy sideskin!



Side channels and small triangular gusset to increase strength! It's a Edition 2 upgrade.



Installing the longeron...





Side skin being laid out....

P.S. all those green bottles on the shelf are Sparkling water my wife likes to drink...might be a few beer bottles mixed in there as well though...
 
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Taiser

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The side skins have extensions that have to be added on them. The seam winds up between the two rear bulkheads...

 
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Taiser

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So once the side skins are kinda done you have to set them up on the bottom skin so you can verify the fit and start drilling through the side longerons. Mess this up and you will be crying for a loooonnnngg time when things don't line up later on during the build.



My contraption for lining up all the skins. The skins are still very floppy so I used 2x4's and lots of strings to keep things up!




Here's a peek inside...you can see some flop but it's the bottom I'm interested in, well that and not having the skin fold over! :)
 

Taiser

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And here it is with the top on. It's amazing how rock solid it gets, even just clecoed together once the top is on...

 

Taiser

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Here's a peek inside with the top on....



Ooooooooooooooooooo .....shiny....
 
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Taiser

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I have a "Edition 2" kit, they are now at #3 but mine includes an upgrade to a gross weight of 1440 lbs. In order to achieve this Zen did a lot of little improvements. One of them are these large gussets. They are pretty thick and beef every thing up considerably. These are on the sides, there are two below them as well on the bottom skin and smaller ones further back...






This is the flap motor bracket. It's made of steel. The flap motor attaches to this bracket and the other end goes on the torque tube, once installed.
 
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Taiser

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Work then starts on the baggage compartment. A lot of screaming went on during this phase. the parts only fit in one way and mostly in a certain order so lots of assembly and dis assembly happened to get it right...







Baggage compartment clecoed..




Another view...
 
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Taiser

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So after the rear fuselage goes together and is mostly all riveted up, then I started on the forward fuselage!



These are the side panels from the forward fuselage. Luckily they are pre-made and come with the kit. They have solid rivets throughout since they carry a lot of load, from the engine to the back. Here they are installed just to make sure they fit because you might have to trim the longerons that are attached to them so they don't hit the back baggage wall.
 

Taiser

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The side channels get done with 2 rows of rivets. The channels themselves are pretty beefy and doubled up to make a "V" on the side skin.

 

Taiser

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Here's a photo of the front of the channel. It also has a 1/4 inch thick "L" on the lower portion that really stiffens things up... It goes where the row of holes is and is secured with A5 rivets.






This is the bottom channel just in front of the access hole in the belly. There is some confusion as to where the side gussets go (in front or in the back) I found that if I put them in the back then everything is just too tight so I installed them in the front. I later found out that it really does not matter which side they are on!
 
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Taiser

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So once the forward fuselage was done I started working on the firewall. Pretty simple set up, unfortunately I ran into problems! One part was major defective, the pre-drilled holes were too far into the curve of the part so the rivets would be at an angle...very bad for strenght... the photos below show the problem, it's really visible on the third one.







Luckily a phone call to Zen with a photograph and they sent me a new part!
 
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