Narfi's Zenith CH750 Super Duty

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VT_Jeff
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Re: Narfi's Zenith CH750 Super Duty

Post by VT_Jeff »

Clecos. Got it! The stuff you learn here!
There are only two seasons in Vermont: boating season, and boat-building season.

Completed Paul Butler 14' Clark Fork Drifter
Completed Jacques Mertens FS14LS + 10%, Build Thread
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Re: Narfi's Zenith CH750 Super Duty

Post by Jeff »

Just too cool Narfi!!!! Jeff

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Re: Narfi's Zenith CH750 Super Duty

Post by narfi »

~4.5hrs
Cut the strips, debuted the edges and bent the spars and doublers for the horizontal and elevator last night.
It's an old brake at a neighbors I am using and it used the full 10ft of it, bending sharper at one end and bowing a little in the middle creaking and groaning the whole time on the .040. I got the angles closeish and will finish them with the hand seamer like I did with the rudder spar. It's close and the bends are straight and where I want them so shouldn't be to hard to finish them off.

Once I have them bent to my satisfaction I will tweak the rib dimensions Roger gave me to match perfectly to the spars and build the new formers and cutting blocks for them.
20210408_213826.jpg
20210408_213826.jpg (87.54 KiB) Viewed 1064 times
Total time spent building: 102 hours
Total Cost: $8803
Airplane + consumables + project specific costs: $5867
Tools, etc.. I will keep for future projects: $2936

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cape man
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Re: Narfi's Zenith CH750 Super Duty

Post by cape man »

I am so enjoying watching this.
The world always seems brighter when you've just made something that wasn't there before - Neil Gaiman

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Re: Narfi's Zenith CH750 Super Duty

Post by Jeff »

Me too Cape Man!! Very much so!!! Jeff

narfi
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Re: Narfi's Zenith CH750 Super Duty

Post by narfi »

~9hrs

Spent an hour Friday working the angles on the spars and doublers.
About 8 hours Sunday afternoon building forming and cutting blocks for the horizontal ribs, cutting them out and forming them.
The first time around when I thought I was building the 750stol ribs I built 3 form blocks, one for the leading edge, one for the middle and one for the full ribs, this time I just made the one full sized former and used my hand seamer to bend the hidden flange on the nose and middle ribs. I still made 3 sets of cutting templates to run the router around for cutting the aluminum.
Of course after forming the ribs I had to dummy them up to the spars to get a peak at how they will look :)
20210411_211806.jpg
Roger is gone to Sun n Fun, so I won't be able to get dimensions on the center hinge assembly parts or rib spacing or attach brackets until he is back next week. Spacing seems most critical on the center two ribs as the forward attach brackets match up with them and from what I can tell need to be spaced appropriately to match the fuselage width and fuselage side of the attach brackets for bolting on. (and I obviously haven't built the fuselage yet....)

I have seen some people build increase the size of the outer hinge bracket to form a strake on the outer ribs of the horizontal. Any thoughts on if I should do that here? I am strongly leaning towards yes. I like the looks of it. It probably does help some. I intend to build floats for it at some time, and although I have not read anything yet about float characteristics for it, nearly all certified aircraft I have put floats on require more stability back at the tail. For example Cessna has a larger rudder and a dorsal fin bolted on under the tail and beavers have a plate bolted on the outer edge of the horizontal stabilizers looking almost exactly like larger versions of what I have seen done on zeniths. What do you guys think?

Also ordered the elevator trim system from Aircraft Spruce, It includes the Servo, clevis/pushrod kit, as well as switches and indicators. $372

Total time spent building: 111 hours
Total Cost: $9175
Airplane + consumables + project specific costs: $6239
Tools, etc.. I will keep for future projects: $2936

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Re: Narfi's Zenith CH750 Super Duty

Post by cape man »

Roger is gone to Sun n Fun...
Tell him to fly 10.33 miles from the western end of the runway on a heading of 226.5 and wave (rock the wings) as he goes over the house. We are the house on the river with a swimming pool. 8) 8)
The world always seems brighter when you've just made something that wasn't there before - Neil Gaiman

narfi
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Re: Narfi's Zenith CH750 Super Duty

Post by narfi »

cape man wrote: Mon Apr 12, 2021 2:51 pm
Roger is gone to Sun n Fun...
Tell him to fly 10.33 miles from the western end of the runway on a heading of 226.5 and wave (rock the wings) as he goes over the house. We are the house on the river with a swimming pool. 8) 8)
You usually go? I think it would be fun to attend things like that, but just not practical for our location and budget at this stage of our life... Though our next cruises are scheduled same time as the Miami boat show next year if they arent canceled (again).

I forgot the picture I took of the ribs I cut out before forming them,
20210411_191143.jpg

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Re: Narfi's Zenith CH750 Super Duty

Post by fallguy1000 »

Is there any types of non-destructive testing that can be done on the custom made aircraft?

I am a curious person is all. Something like a wing connection seems like it might really be important and even potentially fatigue.

My boat has a few places that are pretty critical in heavy head seas, for example..
My boat build is here -------->

viewtopic.php?f=12&t=62495

narfi
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Re: Narfi's Zenith CH750 Super Duty

Post by narfi »

The most common for one-off designs would be testing to destruction.
For "mass produced" plans the designer does the math using materials with known properties as well as testing to destruction.
In both one-off as well as more professional designs, repeating known successes is also very common.

None of that really helps you though.....
If you are talking about testing metal after x numbers of cycles or hours or years, yes there are different types of ndt that can be done.
There is probably an x-ray company in your nearest city capable of x-ray and magnetic partial inspections.
You could probably do some florescent dye penetration inspection yourself to find larger cracks (the size you could probably find with a 10x magnification if looking hard enough) but made much easier with the penetrant and black light

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