Zenith 701

Art VanDelay said:
Wow ! That's a really stupid comment ! I guess you're from stock that thought it was better to stick with horse and buggies than cars as well. "We don't like them thar automobiles - no sir".

Well if you want 1940s technology that weighs a good 60lbs more than yeah - you go with that O-200. I fly a B-777 in my other job I have NO problem with the Rotax 9 series engines. That's probably because I know a thing or two about engines and can recognize a good modern design.
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Good for you. I still don't like them. Don't like engines that sound like chainsaws in an airplane. I never said they weren't good engines, I said I don't like them. Did I mention I don't like them? I also don't like Hondas or Toyotas. They're good cars, I just don't like them. I, too, know a few things about engines.

Please work on your reading comprehension.
 
If you're planning on building a 750, and have a mind to tinker with engines, I do believe the Corvair could be made to work. Personally, I'd like to see someone put the Lycoming IO-233 in one, I bet that it would get off the ground with gusto with that mill under the cowl.
 
The Corvair is a hot little engine for being built by GM. With the right internals and the 5th bearing for prop loads, I would seriously consider one. I had several Corvairs in HS, and the engines were rock solid. According to some Corvair history, because it was the first air cooled car from GM, they overbuilt a lot of the internals. forged rods, cranks, extra bearing area, and good valves and guides. Just needs a prop support out front.
 
docmirror said:
The Corvair is a hot little engine for being built by GM. With the right internals and the 5th bearing for prop loads, I would seriously consider one. I had several Corvairs in HS, and the engines were rock solid. According to some Corvair history, because it was the first air cooled car from GM, they overbuilt a lot of the internals. forged rods, cranks, extra bearing area, and good valves and guides. Just needs a prop support out front.
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Agreed...

Personally, I am amazed someone /company has not created a clone for aircraft use.....:dunno:
 
FormerHangie said:
If you're planning on building a 750, and have a mind to tinker with engines, I do believe the Corvair could be made to work. Personally, I'd like to see someone put the Lycoming IO-233 in one, I bet that it would get off the ground with gusto with that mill under the cowl.
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I wouldn't put in a 233 for personal reasons. While I'm not against auto derivative engines at all (as Ben well knows), I would only do it for a 300+ HP application, like my idea to rebuild a 340/414/421.
 
docmirror said:
Pretty devout following here; http://flycorvair.com/

I"m also interested in a clone. What is really needed is a place that will cast cases and forge crankshafts. Cams, cyl, heads, and other bits are avail aftermarket, but we need cases and cranks. Same with air cooled VW. No more US sources for forged cranks, they are all made in China now, and no one trusts them.

Zenith specific content; http://flycorvair.net/2013/10/29/zenith-750-corvair-reference-page-october-2013/
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Doesn't South Africa make a good amount of VW stuff
 
Art VanDelay said:
Wow ! That's a really stupid comment ! I guess you're from stock that thought it was better to stick with horse and buggies than cars as well. "We don't like them thar automobiles - no sir".

Well if you want 1940s technology that weighs a good 60lbs more than yeah - you go with that O-200. I fly a B-777 in my other job I have NO problem with the Rotax 9 series engines. That's probably because I know a thing or two about engines and can recognize a good modern design.
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Just the mans preference :dunno:


Also is your 777 is powered by a rotax?

I really don't see the relevance, I mean you cant get further apart while staying in aviation, to think your time in a 777 relates one iota to a tiny stick and rudder style zenith.

But hey, why do I know, you fly a 777 :rofl:
 
Ted DuPuis said:
I like reading NTSB reports, so I looked up the various STOL Zeniths. I found 5 or 6, only 1 fatal.

The fatal was a departure stall on a 701 with floats from a lake while over gross. The rest were engine failures. One Mazda rotary, and the rest either were or appeared to be Rotaxes (one 2-stroke). They all walked away.

So, the safety seems pretty good.
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I've got five fatal CH-701 accidents in my 16-year database:

DEN08LA040 (12/15/2007)
ANC09FA062 (7/14/2009)
CEN11FA310 (4/29/2011)
WPR11FA333 (7/17/2011)
ANC13FA095 (9/9/2013)

All Rotax-powered, none was attributed to engine failure.

The fatality rate for the design is pretty good; 11% of accidents result in fatalities compared to ~25% for homebuilts as a whole.

A total of 45 CH-701 accidents in my 1998-2013 database. A Fleet Accident Rate (accidents vs. number of registered examples) a bit higher than average, but a bit better than the Avid and Kitfox.

Ron Wanttaja
 
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Art VanDelay said:
That's probably because I know a thing or two about engines and can recognize a good modern design.
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This made me smile a bit since it was directed at Ted.

Kudos to Ted for the Zen-like reply.

Ted - if you want a tail-dragger, check out the Groppo Trail
http://generalaviationnews.com/2015/10/28/the-groppo-trail-the-lsa-worlds-best-kept-secret/
http://www.flemingaviation.com/tiki-index.php?page=Groppo+Trail

Posted this vid without watching it. Just watched it. Not good.
https://www.youtube.com/watch?v=xn6HjuuWbJ8

Better video:
https://www.youtube.com/watch?v=K0fprF8hH6s
 
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jhausch said:
This made me smile a bit since it was directed at Ted.

Kudos to Ted for the Zen-like reply.
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Thanks :)

I appreciate the links and videos, I'll check them out. Right now we're going to finish up the house projects before we decide to buy a kit plane. Our kitchen is getting close to finished...
 
These are the fatal 701 accidents I see in the NTSB database. My general take is that there are a lot of stalls/spin accidents. I attribute two of these as Experimental accidents, two as "stupid pilot tricks" and the rest as pilots not keeping the airplane flying. Possibly a trait of the 701 that it stalls quickly?

CEN15FA211 - low level stall
CEN15LA026 - hit power lines (Is this a Zenith?)
ANC13FA095 - low level stall
CEN11FA310 - first flight stall/crash, pilot rusty
CEN10LA401 - low level stall
WPR11FA333 - fuel starvation leading to stall. Mechanical or aircraft configuration
ANC09FA062 - overweight

And maybe these two, they aren't "Zenith", but are identified as STOL 701. Modified?

DEN08LA040 - CFIT while flying over his house
CEN11FA310 - departure stall/spin
 
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Low level stall/spin accidents wouldn't inherently surprise me. When you're talking about a STOL aircraft, people are inherently building it and flying it for short fields (duh), which has a risk factor involved.

That does, of course, pose the question of whether that's a goal we want to do. But since they're talking about 100ish ft TO/landing distance, I'd figure aim for a few hundred to be on the safe side.
 
bflynn said:
And maybe these two, they aren't "Zenith", but are identified as STOL 701. Modified?
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Builders can name their homebuilts anything they want; they don't have to use the kit manufacturer's name nor the company's designation for the aircraft. That's one of the big problems when trying to search the NTSB database; there's no standardization in the names.

One of my favorites was listed as a "Bee Dee Five." THAT doesn't come up on a "BD-5" NTSB database search.

When I transfer data from the NTSB database to my personal database, I assign each a "kennel name" that's the usual designation for the type of aircraft (if I can figure it out....).

Ron Wanttaja
 
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Ron, I really appreciate you sharing your NTSB information.
 
Ted DuPuis said:
Ron, I really appreciate you sharing your NTSB information.
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I second that....

Ron does an outstanding job of searching, compiling and arranging data in a logical and accurate result........

Thanks Ron for all you do...:thumbsup:
 
It appears that if you were wanting to build a 750, and had the time and space to do so, you can find a ratty/damaged/project Cessna 150 with a decent engine for not too much money. You could probably sell a lot of the parts for not too much less than you paid for it, and have a good engine for a very reasonable price.
 
Reviving this thread. Some of Ben's old posts in here. :(

It's close to 2 years since I started this thread, and I'm getting more serious. Like to the point of wanting to talk to the Zenith folks at Osh and potentially put some money down if there's a good deal for the show (not sure if Zenith usually does this or not).

It seems that there have been some updates to the 701 kit. The Zenith website says that most panels are now pre-drilled on the 701, which would make assembly significantly easier than original. Does anyone have any knowledge about this? It looks like Zenith is putting some more of the 750 features into the 701.

I also have plotted out the runway on the property. If I remove 3 trees, I can have 360 feet. If I remove 5 trees, I can have 400 feet. This has about 20 ft obstacles. I think that either the 701 or the 750 would do it, but the claims on the website indicate the 701 has a bit of an advantage. The 701 claims takeoff and landing distances in the 60-80 ft range, while the 750 is about double that. Obviously these are published numbers, but when I'm talking about a strip this short, more margin is more better.

@yakdriver had said it took him ~400 hours to build a 750 and he's an experienced builder. I'm not an experienced builder, but I'm not the worst mechanic in the world. Time to build is definitely a factor. I also think I need to sit in both the 701 and the 750 to see how much the cabin space works. Realistically this is something that will be the family flying in primarily, and none of us are particularly large, although I am 6' so reasonably tall.
 
I have flown the Zenith 650 and the 701. The 701 is called a 'sky jeep' for good reason.
 
Ted, how would you power the 701?
 
GeorgeC said:
Ted, how would you power the 701?
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That's a good question, and one that I don't have a full answer to at this point.

As indicated earlier in the thread, we're leaning towards an O-200. The "excessive" in me thinks an O-300 would be better than an O-200, because 145 HP is better than 100 HP. The FAQs on the website say the airplane was designed to be able to handle up to a 300 lb installed weight of the engine, so an O-300 would still work. But an O-200 is ultimately more likely. Part of the reason for that is that we don't like the chainsaw sound produced by the Rotax options or some of the others that spin a lot faster. Something that sounds like a traditional aircraft engine is a positive for us, because part of the point of this is to have some sort of "olden days" feel, of just flying around off a short grass strip because it's fun to count cows and fly around.

The nice thing is that I wouldn't have to decide on the firewall forward until well into the build process.
 
Mike Smith said:
You gotta read the whole thread, Ted would clearly power it by Rotax. :D

Dang it, he beat me to the reply.
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Being a tinkerer (and especially now that we're without Ben) doing some kind of conversion is appealing. I even like the Harley engine conversion idea. Used O-200s and O-300s are pretty cheap, and they're dirt simple to work on. O-235s aren't hard to come by, either. But their parts aren't necessarily cheap.

The first decision to be made is which plane to go with, and the engine would come somewhere down the line, after I got far enough into the build process to think it might have a chance of flying.
 
Hard to beat an 0-200 for acquisition cost and overhaul cost. Being experimental there are lots of ways to up the HP on them too. An O-235 L2C with the high compression pistons would be a nice fit as well with 125HP. Overhaul cost are slightly higher however.
 
I had a chat with a coworker who's on his 2nd build (both RVs). I think from talking to him it makes more sense for me to buy the kit in sections. Zenith does seem to be doing updates to the aircraft, and it helps to "spread out the pain" financially. Plus I'm not going to just sit down and build this, it will take a couple years most likely.

Grum.Man said:
Hard to beat an 0-200 for acquisition cost and overhaul cost. Being experimental there are lots of ways to up the HP on them too. An O-235 L2C with the high compression pistons would be a nice fit as well with 125HP. Overhaul cost are slightly higher however.
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I'm thinking that I want to aim for closer to 125 HP. Yes, the O-235 has the benefit of doing that out the door, but like you said the O-200 can get upgraded as experimental. A modified O-200 might be the way to go. I also do want to run it on MoGas, though, so that's another consideration. Want this to be a cheap operator and cheap fuel is part of it. But I want horsepower.
 
But enough about you, Ted. Why don't you build an O-200 750 cruzer and then sell me the winning raffle ticket? :)
 
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GeorgeC said:
But enough about you, Ted. Why don't you build an O-200 750 cruzer and then sell me the winning raffle ticket? :)
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Because whatever we build will be STOL, not a Cruzer. And after we build it, we want to fly it with the kids for a few years. When they get to be teenagers and stop thinking mom and dad are cool, then maybe we'd reconsider selling it. :)
 
Ted DuPuis said:
I had a chat with a coworker who's on his 2nd build (both RVs). I think from talking to him it makes more sense for me to buy the kit in sections. Zenith does seem to be doing updates to the aircraft, and it helps to "spread out the pain" financially. Plus I'm not going to just sit down and build this, it will take a couple years most likely.



I'm thinking that I want to aim for closer to 125 HP. Yes, the O-235 has the benefit of doing that out the door, but like you said the O-200 can get upgraded as experimental. A modified O-200 might be the way to go. I also do want to run it on MoGas, though, so that's another consideration. Want this to be a cheap operator and cheap fuel is part of it. But I want horsepower.
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They make Corvair firewall forward kits that would get you the HP and MoGas. Just know that to properly build a Corvair for airplane duty it will cost just as much as a Cont/Lyco engine.
 
Ted DuPuis said:
I'm thinking that I want to aim for closer to 125 HP. Yes, the O-235 has the benefit of doing that out the door, but like you said the O-200 can get upgraded as experimental. A modified O-200 might be the way to go. I also do want to run it on MoGas, though, so that's another consideration. Want this to be a cheap operator and cheap fuel is part of it. But I want horsepower.
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Why wouldn't the modified 235 be able to run Mogas? Compression won't allow it?
 
Greg Bockelman said:
Why wouldn't the modified 235 be able to run Mogas? Compression won't allow it?
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It might run MoGas. It depends on the level of modification and the grade of MoGas I want to run.
 
ktup-flyer said:
It's been done a couple times.
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I'm sad that he taxied to the other end in that video. Or that the camera person didn't go down there. Watching a STOL airplane take off from the departure end is always disappointing. Ha.
 
denverpilot said:
I'm sad that he taxied to the other end in that video. Or that the camera person didn't go down there. Watching a STOL airplane take off from the departure end is always disappointing. Ha.
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My coworker made the point that it always amuses him to see Zeniths based at 5,000 ft, towered airports.

Being based at a house with a 360 ft run is much better.
 
Really, the problem with the turbine 701 is the fuel burn. Reading the one built from a small (~90 HP) turbine, cruise fuel burn is ~12 GPH. Meanwhile, even an O-300 would have a (high power) cruise burn of probably ~6 GPH, depending on how I felt like running it, plus significantly more horsepower. The small turbine has cool factor but not much for practicality. Plus a lot of messing around to make it work, whereas I can just bolt up an O-whatever and have it work.
 
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