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CH620

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ashontz

Joined: 27 Dec 2006
Posts: 723

Posted: Wed Apr 25, 2007 3:26 pm Post subject: CH620

I see on the front page that this forum is dedicated to all the Zenith planes including the CH620. Is anyone building this plane? Were plans ever available. That would be an interesting bird to build if it's available in plans.

Gig Giacona

Joined: 10 Jan 2006
Posts: 1416
Location: El Dorado Arkansas USA

Posted: Thu Apr 26, 2007 5:30 am Post subject: Re: CH620

The 620 was the Gemini right? If so only one was built and it was the one done by the factory. I asked about plans when I went through the rudder workshop back in 2002 and was told, "no they aren't available and probably wouldn't be."

_________________
W.R. "Gig" Giacona
601XL Under Construction
See my progress at www.peoamerica.net/N601WR

ashontz

Joined: 27 Dec 2006
Posts: 723

Posted: Thu Apr 26, 2007 5:45 am Post subject: Re: CH620

 	  Gig Giacona wrote: 	
		  The 620 was the Gemini right? If so only one was built and it was the one done by the factory. I asked about plans when I went through the rudder workshop back in 2002 and was told, "no they aren't available and probably wouldn't be." 	




Wonder why?



Wonder if someone like Mark Townsend would be interested in putting together some plans based on a 601HD. The body doesn't look any different from an HD, I'd imagine the spar is probably stronger. It would probably need a larger rudder than an HD too. Those are the major differences I can think of.

Gig Giacona

Joined: 10 Jan 2006
Posts: 1416
Location: El Dorado Arkansas USA

Posted: Thu Apr 26, 2007 5:56 am Post subject: Re: CH620

It was proabably a purely marketing decision. The LSA stuff was just beginning to look like it would happen and it was obvious that that is where the market was going. Add to that they had just changed over to the XL being the primary bird and while really cool the twin would not have given you that much more performance, well at least not enough for the cost difference, than an XL.



Also, the big advantage of a twin would be pretty much non-existent because I doubt single engine performance would have been that good with a single Jab 2200.



A much more logical twin would be based on a 604.

_________________
W.R. "Gig" Giacona
601XL Under Construction
See my progress at www.peoamerica.net/N601WR

ashontz

Joined: 27 Dec 2006
Posts: 723

Posted: Thu Apr 26, 2007 6:03 am Post subject: Re: CH620

 	  Gig Giacona wrote: 	
		  It was proabably a purely marketing decision. The LSA stuff was just beginning to look like it would happen and it was obvious that that is where the market was going. Add to that they had just changed over to the XL being the primary bird and while really cool the twin would not have given you that much more performance, well at least not enough for the cost difference, than an XL.



Also, the big advantage of a twin would be pretty much non-existent because I doubt single engine performance would have been that good with a single Jab 2200.



A much more logical twin would be based on a 604. 	




I forgot about the 640. Yeah, that would be better. Still, for people who like the build, the 620 would be cool. I remember in one of Chris's old videos he mention his inspiration for the 620 was when flying over the Bahamas and thinkin what would he doe if he lost and engine over shark infested waters.

zodierocket(at)hsfx.ca
Guest

Posted: Thu Apr 26, 2007 6:12 am Post subject: CH620

Don't rule the Gemini out. However, don't expect to see it any time in

the next few years. I love the idea and concept of the twin but the work

involved is a lot more then you think. To make a twin that flies is easy

but to make a twin that can do everything safely on one engine is very

hard. The Gemini if ever released will not look anything like it does

now in my opinion. Unfortunately, Zenith is too busy with other things

to even have a discussion about it. However, I spent several hours

talking to Chris about it last year and going over his drawings. All I

can hope for is someday we'll hear more. For now it is not realistic to

discuss in detail because details are completely changing.



Mark Townsend  Alma, Ontario

Zodiac 601XL C-GOXL, CH701 just started

www.ch601.org / www.ch701.com / www.Osprey2.com

--

ashontz

Joined: 27 Dec 2006
Posts: 723

Posted: Thu Apr 26, 2007 6:17 am Post subject: Re: CH620

 	  zodierocket(at)hsfx.ca wrote: 	
		  Don't rule the Gemini out. However, don't expect to see it any time in

the next few years. I love the idea and concept of the twin but the work

involved is a lot more then you think. To make a twin that flies is easy

but to make a twin that can do everything safely on one engine is very

hard. The Gemini if ever released will not look anything like it does

now in my opinion. Unfortunately, Zenith is too busy with other things

to even have a discussion about it. However, I spent several hours

talking to Chris about it last year and going over his drawings. All I

can hope for is someday we'll hear more. For now it is not realistic to

discuss in detail because details are completely changing.



Mark Townsend  Alma, Ontario

Zodiac 601XL C-GOXL, CH701 just started

www.ch601.org / www.ch701.com / www.Osprey2.com

-- 	




That's a shame. It would be a neat project.

bryanmmartin

Joined: 10 Jan 2006
Posts: 1018

Posted: Thu Apr 26, 2007 6:24 am Post subject: CH620

One factor I've heard mentioned is the lack of a feathering propeller  

for engines in that class.



On Apr 26, 2007, at 9:56 AM, Gig Giacona wrote:



 	  Quote: 	
		   

 <wr.giacona(at)suddenlink.net>



 Also, the big advantage of a twin would be pretty much non-existent  

 because I doubt single engine performance would have been that good  

 with a single Jab 2200.




	


-- 

Bryan Martin

N61BM, CH 601 XL,

RAM Subaru, Stratus redrive.

do not archive.

_________________
--
Bryan Martin
N61BM, CH 601 XL, Stratus Subaru.
do not archive.

ashontz

Joined: 27 Dec 2006
Posts: 723

Posted: Thu Apr 26, 2007 6:26 am Post subject: Re: CH620

 	  bryanmmartin wrote: 	
		  One factor I've heard mentioned is the lack of a feathering propeller  

for engines in that class.



On Apr 26, 2007, at 9:56 AM, Gig Giacona wrote:



 	  Quote: 	
		   

 <wr>



 Also, the big advantage of a twin would be pretty much non-existent  

 because I doubt single engine performance would have been that good  

 with a single Jab 2200.

	


-- 

Bryan Martin

N61BM, CH 601 XL,

RAM Subaru, Stratus redrive.

do not archive. 	




That's a good point. You could always go with an Ivoprop adjustable prop.



do not archive

crvsecretary

Joined: 18 Mar 2007
Posts: 38
Location: Naugatuck, CT

Posted: Thu Apr 26, 2007 6:43 am Post subject: CH620

I recall reading an article some time back where CH was quoted as saying  ( and I am paraphrasing here....) that the Gemini prototype performed well in  all regards EXCEPT single-engine climb.  The lack of a fully-featherable  prop for the Jabaru 80 hp (and the drag associated with it while one engine is  stopped) made the plane unable to climb acceptably.

  

 I wish I could remember the source of this info...it was a magazine  article....but after that I'm at a loss.

  

 It seems to me the Gemini is the answer to a question no one is  asking.  Sure, it would be VERY unique, but as a whole sales of twins are  down.....so why would a kit manufacturer want to offer such a product with such  limited appeal?  Certainly this would not be a first-time-builders  project.  It's nice to dream...but how many kits would truely  sell?   I would think if I had Van's breathing down my back with a  Zodiac Clone I'd would not have time to even THINK about a specialty bird like  the Gemini.

  

 But it sure would be a neat plane !!!!!!!!

  

 Tracy Smith

 CH601XL

 N458XL (reserved)

 Naugatuck, CT

  

  

  

 

Gig Giacona wrote:

 	  Quote: 	
		   The 620 was the Gemini right? If so only one  was built and it was the one done by the factory. I asked about plans when I  went through the rudder workshop back in 2002 and was told, "no they aren't  available and probably wouldn't be."


	




Wonder why?



Wonder if  someone like Mark Townsend would be interested in putting together some plans  based on a 601HD. The body doesn't look any different from an HD, I'd imagine  the spar is probably stronger. It would probably need a larger rudder than an HD  too. Those are the major differences I can think of.



--------

Andy  Shontz

CH601XL - Corvair

www.mykitlog.com/ashontz

 

  



See what's free at AOL.com. 

  [quote][b]

_________________
Zenith 601XL N458XL (reserved)
Naugatuck, CT
Tail Complete; working on wings

dbortol

Joined: 02 Sep 2006
Posts: 46

Posted: Thu Apr 26, 2007 8:39 am Post subject: CH620

I was talking with a couple of the instructors at the school where I rent about their twin, which is a Piper Seneca. They said feathering the prop requires oil pressure from the engine, and if the RPM falls below 800 there isn't enough pressure. So at the first sign of engine trouble they have to feather the prop immediately, before the engine shuts down. They also said that near max gross weight on a hot day there isn't enough power from the remaining engine to maintain flight. This put a big dent in my perception of twin engine safety... 

  

 do not archive

  

 Dino Bortolin



 

 On 4/26/07, Bryan Martin <bryanmmartin(at)comcast.net (bryanmmartin(at)comcast.net)> wrote: [quote]--> Zenith-List message posted by: Bryan Martin <bryanmmartin(at)comcast.net  (bryanmmartin(at)comcast.net)>



One factor I've heard mentioned is the lack of a feathering propeller

for engines in that class.



On Apr 26, 2007, at 9:56 AM, Gig Giacona wrote:



 	  Quote: 	
		   --> Zenith-List message posted by: "Gig Giacona" 

 <wr.giacona(at)suddenlink.net (wr.giacona(at)suddenlink.net)>



 Also, the big advantage of a twin would be pretty much non-existent

 because I doubt single engine performance would have been that good 


	


[b]

nyterminat(at)aol.com
Guest

Posted: Thu Apr 26, 2007 10:20 am Post subject: CH620

They can be feathered with an electric prop

    

  

 --

dredmoody(at)cox.net
Guest

Posted: Thu Apr 26, 2007 10:36 am Post subject: CH620

Hence the expression that the second engine is there to make sure you get to the crash site promptly.



Dred



 	  Quote: 	
		   From: dbortol(at)gmail.com

 To: zenith-list(at)matronics.com

 

 I was talking with a couple of the instructors at the school where I rent about their twin, which is a Piper Seneca. They said feathering the prop requires oil pressure from the engine, and if the RPM falls below 800 there isn't enough pressure. So at the first sign of engine trouble they have to feather the prop immediately, before the engine shuts down. They also said that near max gross weight on a hot day there isn't enough power from the remaining engine to maintain flight. This put a big dent in my perception of twin engine safety... 

  

 do not archive

  

 Dino Bortolin

kkinney

Joined: 11 Jan 2006
Posts: 42

Posted: Thu Apr 26, 2007 10:47 am Post subject: Re: CH620

There's one in in my neck of the woods.  



I'll ask the builder if he minds if I post his email address.



Regards,

Kevin Kinney

Trainnut01(at)aol.com
Guest

Posted: Thu Apr 26, 2007 10:47 am Post subject: CH620

Dino 

 Somewhere I heard that one of Lindberg's reasons for using a single engine  aircraft in his Atlantic crossing was that a twin would not stay in the air on  one engine considering the fuel load, and having two engines doubles  the chance of one quitting.

 Carroll

  

 do not archive



See what's free at AOL.com. 

  [quote][b]

Peter Barthold

Joined: 24 Apr 2006
Posts: 25
Location: Germany

Posted: Fri Apr 27, 2007 4:01 am Post subject: Re: CH620

Gentlemen,



your information about featherable propellers is not correct!



I own a 160 cm dia prop from HOFFMANN which I intend to bolt to the business end of my HDS one day. It is mechanically operated and has 3 pitch settings: 1. Take off, 2. Cruise, 3. feather (sailplane operation).

It originates from a Grob G109B touring motorglider and was swung by a 2500ccm VW based engine rated 85hp.



the G109B was introduced in 1983 (and sold in considerable numbers to the British RAF as trainer) so this is not new at all.



Cheers 



Peter

HDS TDO

Tail complete

Wings in progress

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