# Narfi's Scratch Built Zenith 750 Super Duty

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#### Topaz

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What, you mean it gets cold where you are? ...
Hey, come on, VB! It get's cold here in SoCal, too! I mean, it's likely to get down into the mid-seventies this week! I'll need to break out the parka!

#### narfi

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Hey, come on, VB! It get's cold here in SoCal, too! I mean, it's likely to get down into the mid-seventies this week! I'll need to break out the parka!
Well its been too cold for even me last week or so, but it warmed up 20-30 degrees so its warm enough to snow now and I'm back working in the tent

#### Topaz

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Well its been too cold for even me last week or so, but it warmed up 20-30 degrees so its warm enough to snow now and I'm back working in the tent
Oh you guys with your Metric. So yes, 68-86°F. Lovely weather.

#### narfi

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As mentioned above it warmed up to around 25-28ish F which is warm enough to get our first snow to stick for the winter.

I was able to take off my jacket and just wore a thick sweatshirt with a labcoat over to keep most of the dust off.

2 more hours got the cutting templates and form blocks done for the rear wing ribs.

My wife came out and helped me unroll the aluminum and get it into the rack. Left out a sheet of .016 to start cutting up as well as the .020 I have already cut into. I had made the two stabilizer end ribs, but for the superduty there are actually 2 end ribs on both sides as the forward spar doesn't extend to the tip.

Total time spent building: 24 hours
Total Cost: $8276 Airplane + consumables + project specific costs:$5340
Tools, etc.. I will keep for future projects: $2936 #### narfi ##### Well-Known Member Log Member Yes.... it had been just under 0f all week, so when it warms up ~30 degrees it feels pretty nice #### narfi ##### Well-Known Member Log Member About 10 more hours this weekend got some visable progress. Cut out and bent two more stabilizer end ribs since each side uses 2 instead of one with the partial length spar. Then cut and bent all the rest of the horizontal and elevator ribs as well as the rear wing ribs. Still need to cut and flange the lightning holes in the wing ribs, tool kit that has the hole cutter from aircraft spruce is still backordered so may end up with another ghetto set-up since it worked so well making the dies. 1/4" end bearing router bit is supposed to get here from amazon this week, tracking says it was in state Friday. Then I can cut out the slat and flaperon ribs, they are smaller peices with tighter radius flanges so the 3/8" I have been using is too big for them. The cutting and bending of all the ribs went very quick and easy imo, I probably spent more time making the templates and forms, but well worth the time and effort, I am quite pleased with how they look. (Esp. Knowing how much(textron?) Piper, Cessna and Beech charge for each little peice Total time spent building: 34 hours Total Cost:$8276
Airplane + consumables + project specific costs: $5340 Tools, etc.. I will keep for future projects:$2936

#### narfi

##### Well-Known Member
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Cut the lightning holes in all the rear wing ribs and flanged them. Used my router with a peice of plywood screwed to it as my hole cutter with 1/4" holes and a bolt as my pivot point in the tooling holes.

First hole I cut the center hole to the larger hole dimensions so that rib was scrap..
After finishing I cut out a replacement rib blank and bent it over the forming blocks. I had my ghetto hole cutter set to the smallest hole size so cut it first...... however it was only supposed to have the 2 larger holes cut in it so reinforcement could be riveted to it on the fuel bay..

so in the end I have 1 extra rib(I still flanged it so it is a good completed rib) and one scrap rib.

Flanging with the dies was easy just using a rubber mallet. I was just careful to keep them square and hold pressure down on the male die once started to prevent it bouncing, I didnt just wail away at it with the mallet but more controlled hits mostly centered to start, then finished off around the parameter once down mostly formed.

On the zenith forum someone posted yesterday having issues with his ribs being warped after hand flanging(not using a die) so I payed close attention to mine to see the difference.

You can see it is stretched some but snaps back straight when the edge flanges are held at 90° so I think it is ok.

All in all, not bad for an evening after work

Total time spent building: 37.5 hours
Total Cost: $8276 Airplane + consumables + project specific costs:$5340
Tools, etc.. I will keep for future projects: 2936 #### narfi ##### Well-Known Member Log Member 2.5hrs last night. Smaller end bearing router bits came in so cut out all the slat and flaperon blanks.. Cut out all the flaperon blanks individually which took most of the time then got impatient and stacked up all the slat blanks to cut at the same time. Not a good idea with cheap bearing bits... I promptly burned it up and blew up the bearing. Ill probably need to redo one or two of them as they weren't quite aligned in the stack and missing some of the edges.. Lesson learned,, all things in moderation. Maybe 3 or 4 stacked to save time but dont try to cut 10 blanks at once with cheap tools. Still happy with the results though Total time is up to 40hrs or a standard work week. As a hobby it feels like I have got a lot done, but if I was on the clock I might be ashamed to have so little to show...... It is a hobby though so all good Total time spent building: 40 hours Total Cost:8276
Airplane + consumables + project specific costs: $5340 Tools, etc.. I will keep for future projects:$2936

#### Victor Bravo

##### Well-Known Member
HBA Supporter
Excellent progress Narfi ! Keep pounding that aluminum at high speed!

#### rbarnes

##### Well-Known Member
Narfi, did they tell you when the complete dimensional drawings will be released ? Ordered a set of plans and was disappointed when only assembly drawings showed up without them even mentioning the actual plans wouldn't be included yet.

#### narfi

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Narfi, did they tell you when the complete dimensional drawings will be released ? Ordered a set of plans and was disappointed when only assembly drawings showed up without them even mentioning the actual plans wouldn't be included yet.
No, they said they are hoping to have them finished sometime this winter but I'm not really sure. I called before ordering and talked to Roger. Told him I wasn't in a huge rush but wanted to get started making parts this winter to keep me out of trouble then maybe start assembly next summer or winter. He included the blueprints for the 750stol as well as the 750 super duty assembly drawings when I ordered them. Since I had talked to him about it their order desk knew what to expect with my order and he had highlighted some items on the stol drawings for me to start with, then I have called him each week and he has told me more parts still in the stol drawings that are compatable with the super duty so I can build them.

I think the biggest issues will be spars and some of those other things, it seems the rudder will probably be different as well.....

You should call Roger on Monday and explain you bought the plans hoping to start building and ask if they could send you some drawings to get started on until they have the plans finished.

#### narfi

##### Well-Known Member
Log Member
2.5hrs got all the slat and flaperon ribs bent.
1hr yesterday got the wing nose rib forms and cutting templates ready, but while it was in the teens F° the wind was cutting through the tent pretty well and mechanics gloves just weren't enough :/ 5° this morning so progress may slow down a bit if my body goes into hibernation mode. Will see

Total time spent building: 43.5 hours
Total Cost: $8276 Airplane + consumables + project specific costs:$5340
Tools, etc.. I will keep for future projects: $2936 #### Little Scrapper ##### Well-Known Member HBA Supporter Log Member Awesome project! #### narfi ##### Well-Known Member Log Member 1hr was all my fingers could take of the cold last night, hot coffee and rum don't seem to help the toes and fingers much. Got the wing butt nose rib formers done. Picture includes the main nose rib I did Sunday, still need to grind the fluting in them but that's pretty quick. Someone posted yesterday stating I would spend 10s of thousands of dollars and never have a flying airplane. I wanted to quickly address that in saying that while someone should be aware of their limitations before starting a project like this, I took all precautions before beginning to ensure I was prepared to see the project through. I set myself a reasonable timeline 3yrs(which I currently have a hard time seeing how I can drag it out that long) and a commitment to plug away at it one bite at a time. It is fun for me, and even when it is painfully cold, I still want to be working on it and will push to put in that hour or two each day because I enjoy it and it is therapeutic for the mind and body to end a day with no stress, just focusing on a fun productive project. Total time spent building: 44.5 hours Total Cost:$8276
Airplane + consumables + project specific costs: $5340 Tools, etc.. I will keep for future projects:$2936

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#### Victor Bravo

##### Well-Known Member
HBA Supporter
Someone posted yesterday stating I would spend 10s of thousands of dollars and never have a flying airplane.
Two of my associates from Brooklyn, Louie the Fish hook and Golf Club Jimmy want to have a word with whoever said that. Additionally, I have made special arrangements to give a pair of Cleco pliers to Moe Howard (formerly of the Three Stooges) to adjust that person's nose after the first two are done.

#### narfi

##### Well-Known Member
Log Member
2.5hrs
Made the form and cutting blocks for the wing root ribs and ground out the fluting grooves in it and the nose rib blocks I had forgot to grind them into.

The root ribs top flange goes from 60° at the nose to 90° at the rear spar. I puzzled over best way to do that and decided to just make the forms like all the others and free handedly not beat it down all the way at the front. As easy as cutting out and bending is once the forms are made, I can try a couple if I mess up one or two, and I only need a good left and a good right, so not worth trying to overthink the formers..... We will see

Total time spent building: 47 hours
Total Cost: $8276 Airplane + consumables + project specific costs:$5340
Tools, etc.. I will keep for future projects: \$2936

#### narfi

##### Well-Known Member
Log Member
0 hours
Went to start building the rear bulkheads last night and found a contradiction in the dimensions, so called it early and binge watched some shows my son was wanting to watch.

Called Roger this morning and he is looking into it as well as more parts for me to build.
Anyone know what scratch builders are doing for the tips of the flaperons, slats and wings? they all seem to be plastic or fiberglass parts. Just thinking ahead....