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Stefan

Joined: 30 Sep 2008
Posts: 59

Posted: Wed Oct 08, 2008 4:59 pm Post subject: Zenith CH750 Detail Pictures

I had the opportunity to visit ZAC in Missouri last month and took over a hundred detail pictures of the 750. Thanks to the folks at ZAC I was also able to fly in the CH750 and was extremely impressed. Since a friend of mine and myself are now starting to build one of these very nice airplanes we put the pictures up on the web and hopefully folks find them useful.



The site is at:



http://www.ch750.ca



got to the details page for all the pictures. The website is still under construction and will be updated frequently. Comments and suggestions greatly appreciated.



Stefan

kmccune

Joined: 22 Sep 2007
Posts: 577
Location: Wisconsin, USA

Posted: Thu Oct 09, 2008 3:58 am Post subject: Re: Zenith CH750 Detail Pictures

Nice pics! 



Thanks



Kevin

_________________
“Always do what you are afraid to do.”
R.W. Emerson (1803-1882)

"Real freedom is the sustained act of being an individual." WW - 2009

"Life is a good deal...it's worth it" Feb 1969
Dorothy McCune

bigeagle(at)telus.net
Guest

Posted: Thu Oct 09, 2008 8:46 am Post subject: Zenith CH750 Detail Pictures

Stefan,

  

 It's encouraging to see a CH750 being built in  Canada, not too far from me.  I'm in southern BC and I'll be building mine  from plans as soon as they become available.  Your website is the first I  know of for a 750 build and I'm sure many will be checking it out  frequently.  I have an observation... not a complaint... and a  suggestion... Your picture viewer makes it difficult for others to download  copies of the photos.  If you want to make your photos more readily  available you may want to consider a free program such as Web Photo Album from  http://www.vicman.net/.  I used it on  my website (non-UL related)... http://www3.telus.net/CMA-MOH/Past%20Pics.htm   At any rate, I want to congratulate you on your new website.  I for one  will be checking it out often.  Please take and post LOTS of  pictures.

  

 Chris (aka  Brillo1)



    [quote][b]

Stefan

Joined: 30 Sep 2008
Posts: 59

Posted: Thu Oct 09, 2008 10:38 am Post subject: Re: Zenith CH750 Detail Pictures

Thanks!



Appreciate the feedback. Will check the software out today. 



Stefan

Stefan

Joined: 30 Sep 2008
Posts: 59

Posted: Thu Oct 09, 2008 11:23 am Post subject: Re: Zenith CH750 Detail Pictures

Made the changes to the photo album. Now images come up with a nice resolution. Thanks Chris, great suggestion.



Stefan

bigeagle(at)telus.net
Guest

Posted: Fri Oct 10, 2008 8:51 am Post subject: Zenith CH750 Detail Pictures

Stefan,

  

 Which engine are you going with?  I'm  seriously considering a WW Corvair.  Not 100% sold on it yet.

  

 Chris

  

    [quote][b]

Stefan

Joined: 30 Sep 2008
Posts: 59

Posted: Sat Oct 11, 2008 7:56 pm Post subject: Re: Zenith CH750 Detail Pictures

Good question.



I am not sure. I was planning on putting the CH750 on floats. Will need the most powerful light weight engine around. Best choice seems to be the Jabiru 3300 so far. Glad I still have a year + to sort that one out. I am not sure on the Corvairs. Maybe once Aeromax put an additional bearing in and they are able to test it.



All the best,



Stefan

Brady

Joined: 26 May 2008
Posts: 182
Location: Poulsbo, WA

Posted: Sun Oct 12, 2008 10:42 am Post subject: Re: Zenith CH750 Detail Pictures

Stefan,



I don't mean to down talk the Jabiru 3300.

But the advertised weight is dry weigh.

I have to say that I think the Jabiru has room for improvement.



I think for the money you can get a much better engine.

You can buy a completely built Corvair with all the bells & whistles for substantially less than the Jabiru.



Granted I am very Biased towards the Corvairs.

I build Corvair Conversions and My next engine is being designed to compete Directly with the 3300.



So far I feel comfortable saying that I think my next engine will be lighter than the Jabiru installed with comparable or better power. 



That being said; I want to point out another advantage to the Corvair over the Jabiru & Rotax. And that is parts availability and cost.

I think most people look at the initial cost, power, and  weight too closely and forget to think down stream a bit.



Can you buy Jabiru and Rotax parts at your local auto parts store?

What is the difference in cost for any given part compared to a Corvair?



I urge you to keep a close eye on the Corvair movement and learn as much as possible about the builders as you can.



William Wynne's web site is full of information: www.flycorvair.com



Mark Langford's site is equally informative: http://home.hiwaay.net/~langford/



Food for thought,

_________________
Brady McCormick
Poulsbo, WA
www.magnificentmachine.com

bigeagle(at)telus.net
Guest

Posted: Sun Oct 12, 2008 10:48 am Post subject: Zenith CH750 Detail Pictures

Sounds like you and I have the same gameplan.   Amphibs are in my long range plans, but initially I want to fly with the Tundra  tires for awhile.  As far as engines go, the Corvair is beyond a doubt the  most bang for the buck, but it's a bit heavy and may not provide the prop torque  we're looking for.  The Jab 3300 vs Rotax 912S info below shows the two to  be close with properly trimmed props, but then there are several other factors  to consider as well.  Personally, I'd prefer a six banger purring along at  2750 RPMs over a 4 at 5500 any day.

  

  

Rotax versus Jabiru - Anticipated Ground Static  Thrust for a Certain Propeller 

A propeller will produce a certain thrust based on  the torque and RPM it experiences. Consequently, an engine comparison can be  done from this.                   

Engine        Type<?xml:namespace prefix = o ns =        "urn:schemas-microsoft-com:office:office" />            

Model            

Power        (HP)            

Engine        RPM            

Calculated        Engine Torque            

Actual Torque        (Ft Lb)            

Reduct. Gear        *            

Prop        RPM            

Prop Torque (Ft        Lb)            

Fuel rate        (L/Hr)            

Comments               

Rotax            

582(4            

63            

6500            

50.9            

50.1            

2.58            

2519            

129            

27.3            

Max 6800 RPM,        with lower torque.               

Rotax            

582(4            

65            

6250            

54.6            

54.0            

2.58            

2422            

139            

27.0            

                

Rotax            

582(4            

63            

6000            

55.1            

55.3            

2.58            

2326            

143            

26.0            

Max        torque.               

Rotax            

582(40)            

53.6            

5500            

50.1            

50.0            

2.58            

2132            

129            

22.0            

Max torque. Max        6400 RPM, with a lower torque.               

             

             

             

             

             

             

             

             

             

             

                

Jabiru            

2200            

84            

3300            

133.7            

134.0            

1            

3300            

134            

18.0            

Jab with Mod        combust chambers.               

Jabiru            

2200            

75            

2900            

135.8            

136.0            

1            

2900            

136            

16.0            

Max torque = 137        Lbf Ft (at) 2700 RPM               

Jabiru            

2200            

62            

2400            

135.7            

135.0            

1            

2400            

136            

14.0            

14 L/hr (at) cruise        (75%)               

             

             

             

             

             

             

             

             

             

             

                

Rotax            

912            

81            

5800            

73.3            

72.3            

2.273            

2552            

164            

22.8            

Max 5 min (at) this        RPM.               

Rotax            

912            

78            

5500            

74.5            

74.0            

2.273            

2420            

168            

22.0            

Max cont. pwr        RPM.               

Rotax            

912            

75            

5200            

75.8            

75.6            

2.273            

2288            

172            

21.5            

                

Rotax            

912            

73.5            

5000            

77.2            

77.5            

2.273            

2200            

176            

21.2            

Max        torque.               

Rotax            

912            

68.5            

4800            

75.0            

75.0            

2.273            

2112            

170            

20.6            

                

Rotax            

912            

62            

4350            

74.9            

74.0            

2.273            

1914            

168            

19.2            

                

             

             

             

             

             

             

             

             

             

             

                

Jabiru            

3300            

126            

3300            

200.5            

199.0            

1            

3300            

199            

28.5            

With Mod        combustion chambers.               

Jabiru            

3300            

120            

3100            

203.3            

203.0            

1            

3100            

203            

27.1            

                

Jabiru            

3300            

113            

2900            

204.6            

205.0            

1            

2900            

205            

25.6            

                

Jabiru            

3300            

109            

2750            

208.2            

208.0            

1            

2750            

208            

24.7            

Max        torque.               

Jabiru            

3300            

100            

2550            

206.0            

206.0            

1            

2550            

206            

22.6            

                

Jabiru            

3300            

93.5            

2387            

205.7            

205.0            

1            

2387            

205            

21.1            

Advertised fuel        rate = 20 L/hr at cruise.               

Jabiru            

3300            

88            

2263            

204.2            

204.0            

1            

2263            

204            

19.9            

                

Jabiru            

3300            

84            

2145            

205.7            

203.0            

1            

2145            

203            

19.0            

                

Jabiru            

3300            

80            

2058            

204.2            

203.0            

1            

2058            

203            

18.1            

                

             

             

             

             

             

             

             

             

             

             

                

Rotax            

912S            

100            

5800            

90.6            

89.2            

2.43            

2387            

217            

27.0            

Max 5 min for        take-off.               

Rotax            

912S            

95            

5500            

90.7            

91.5            

2.43            

2263            

222            

26.0            

Max cont.        pwr.               

Rotax            

912S            

90            

5000            

94.5            

94.4            

2.43            

2058            

229            

20.0            

                

Rotax            

912S            

86            

4800            

94.1            

94.6            

2.43            

1975            

230            

18.0            

Max        torque. 

* Assume minimal loss from engine torque to prop  torque in reduction gear. 

Conclusion: For a similar prop, anticipate Jabiru 3300 to have greater static  thrust than Rotax 912 and slightly lower than 912S with a prop trimmed for 5800  engine RPM. Prop experiencing 2387 RPM & 217 Lbf Ft torque. Note that the  Jabiru 3300 would have 205 Lbf Ft of torque at that 2387 prop RPM. Should trim  prop for Jab optimum 2750 RPM and torque of 209 Lbf Ft. Mario Gaulin, Ontario,  Canada. 29 Oct 2003.

    [quote][b]

Brady

Joined: 26 May 2008
Posts: 182
Location: Poulsbo, WA

Posted: Sun Oct 12, 2008 11:14 am Post subject: Re: Zenith CH750 Detail Pictures

Chris,



Rather than re type all the info, have a look at Marks site.

This link is his camshaft page and as you can see the Corvair will easily produce 197 Foot pounds of torque.



Keep in mind that this is only a 3.1 liter Corvair

I have a slightly larger Corvair in the works and a hydraulic roller cam may be  utilized.



Marks link is: http://home.hiwaay.net/~langford/corvair/cam_advance.html



If you would like to discuss any specifics please feel free to Email me off list.

brady(at)magnificentmachine.com

_________________
Brady McCormick
Poulsbo, WA
www.magnificentmachine.com

gburdett

Joined: 05 Aug 2008
Posts: 13

Posted: Sun Oct 12, 2008 2:16 pm Post subject: Re: Zenith CH750 Detail Pictures

It will be interesting to see how the RotaMax progresses over the next few years- good torque, good weight, and power in the right range by the limited info available but it is in the very early aviation use stage-and it needs a PSRU. A real experiment right now. If it proved to be reliable-it would be a good CH 750 match . Zenith indicates that a 72-maybe a 74 would be the largest prop that would fit well. I believe it is a 72 on it right now although not pitched to perform-just for joy  rides.

Chris Lewis

Joined: 17 Mar 2006
Posts: 56
Location: Seattle

Posted: Mon Oct 13, 2008 11:35 am Post subject: Re: Zenith CH750 Detail Pictures

New Elevator - 



I see the 750 has a new elevator since Osh Kosh. Did you ask them about this? It had a fairly large trim tab added in the original photos and when I saw the prototype in June.



I see that they've also cleaned up the horizontal mounts by flipping the angle bracket 180 degrees. Nice to see some of these "clean-up" details making it onto the factory plane.



Thanks,



Chris in Seattle

_________________
750/ Zen-vair Semi-Scratch Builder
N750XT (reserved)

gburdett

Joined: 05 Aug 2008
Posts: 13

Posted: Mon Oct 13, 2008 11:53 am Post subject: Re: Zenith CH750 Detail Pictures

Chris,  



Yes , they changed the elevator in the last two weeks before the factory day. It was on the table in the shop when I flew the CH 750 in early September. The tail group still has some mods that could be made, additional fairing around the stab now that the brackets are not in the way, VG's on the new elevator, and a larger rudder(just for looks). I am hoping that they are still working which is why I am going to the wing kit next. When I flew the 750 , the continental definitely makes it nose heavy. It was better the second flight with the new elevator, but it still could use some added flare ability at no power and slow speeds.  By the time the wings are done, maybe there will be a few added changes to the tail. The next decision is cuff-no cuff.

Chris Lewis

Joined: 17 Mar 2006
Posts: 56
Location: Seattle

Posted: Mon Oct 13, 2008 1:30 pm Post subject: Re: Zenith CH750 Detail Pictures

The prototype was sporting StolSpeed "Feathers" on the elevator this summer and it seemed to be working well with them on the flights I witnessed (no rides were given back then).  



I'm scratch building and waiting patiently for the updated plans.



Cuff/No Cuff?  Not sure what you mean here. Can you clarify?



Thanks,



Chris in Seattle

_________________
750/ Zen-vair Semi-Scratch Builder
N750XT (reserved)

gburdett

Joined: 05 Aug 2008
Posts: 13

Posted: Mon Oct 13, 2008 1:58 pm Post subject: Re: Zenith CH750 Detail Pictures

Chris,



I was referring to the leading edge slats vs VG's  -there has been a little discussion about it previously. The fellow selling feathers VG's has quite a bit of info and CH talks about the STOL characteristics. Both opinions are based in experience but I think I would trade a little STOL ability for a little more  flare control and maybe cruise. Still working it out in my mind. Roger of ZAC says that if nothing else, the slats look cool-there is always that.

BobCollins

Joined: 12 Aug 2008
Posts: 19
Location: Sunnyvale CA USA

Posted: Tue Oct 14, 2008 10:38 am Post subject: Zenith CH750 Detail Pictures

Gary,

You suggest that they may change the rudder on the 750. That would, of 

course, violate their current message that the 750 has the same rudder 

as the 701. In fact, my daughter and I just built our 701/750 rudder at 

a workshop last weekend. Can you tell us more of what you know?



Bob Collins

Sunnyvale CA USA



gburdett wrote:

 	  Quote: 	
		   



 Chris,  



 Yes , they changed the elevator in the last two weeks before the factory day. It was on the table in the shop when I flew the CH 750 in early September. The tail group still has some mods that could be made, additional fairing around the stab now that the brackets are not in the way, VG's on the new elevator, and a larger rudder(just for looks). I am hoping that they are still working which is why I am going to the wing kit next. When I flew the 750 , the continental definitely makes it nose heavy. It was better the second flight with the new elevator, but it still could use some added flare ability at no power and slow speeds.  By the time the wings are done, maybe there will be a few added changes to the tail. The next decision is cuff-no cuff.





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p 8553#208553

rbjjr

Joined: 18 Mar 2007
Posts: 36

Posted: Tue Oct 14, 2008 5:17 pm Post subject: Re: Zenith CH750 Detail Pictures

Was the spar for the rudder you just built 0.025 or 0.032 thickness?  



I was recently informed that the 750 rudder is the same as the one I had just finished with the exception of the fact that the 750 rudder spar is 0.032.  Mine happened to be 0.025 and I'm replacing it.  I started it a while ago so I apparently missed the change.

BobCollins

Joined: 12 Aug 2008
Posts: 19
Location: Sunnyvale CA USA

Posted: Tue Oct 14, 2008 7:09 pm Post subject: Zenith CH750 Detail Pictures

Hi Burke,



I just attempted to measure the spar thickness on my mostly complete 

rudder and I think it is 0.032. The plans I got say the spar is supposed 

to be 0.025 but the plans were out-of-date in other ways. The plans do 

say that the doublers are to be 0.032. My guess is that the spar are all 

now 0.032 going forward.



I will check with my workshop instructor to confirm the spar thickness 

on my rudder.



Bob Collins

Sunnyvale CA USA



PS. Just a request, but it would be helpful if you would quote the 

message you are responding to (I am assuming it was my message you were 

asking about). Also, please sign your message; I was able to find your 

name in an earlier post of yours. Thanks for listening.  

rbjjr wrote:

 	  Quote: 	
		   



 Was the spar for the rudder you just built 0.025 or 0.032 thickness?  



 I was recently informed that the 750 rudder is the same as the one I had just finished with the exception of the fact that the 750 rudder spar is 0.032.  Mine happened to be 0.025 and I'm replacing it.  I started it a while ago so I apparently missed the change.





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p 8825#208825

kmccune

Joined: 22 Sep 2007
Posts: 577
Location: Wisconsin, USA

Posted: Wed Oct 15, 2008 2:47 am Post subject: Re: Zenith CH750 Detail Pictures

Don't forget that that Jabiru 3300 is limited to a smaller diameter and  lighter prop  then the Rotax. It is pretty close on engine torque vs Rotax prop torque though. But if you going to pony up for the 3300, a little bit more will get you the Rotax. 



Kevin



[quote="bigeagle(at)telus.net"]Sounds like you and I have the same gameplan.   Amphibs are in my long range plans, but initially I want to fly with the Tundra  tires for awhile.  As far as engines go, the Corvair is beyond a doubt the  most bang for the buck, but it's a bit heavy and may not provide the prop torque  we're looking for.  The Jab 3300 vs Rotax 912S info below shows the two to  be close with properly trimmed props, but then there are several other factors  to consider as well.  Personally, I'd prefer a six banger purring along at  2750 RPMs over a 4 at 5500 any day.

    torque in reduction gear. 

Conclusion: For a similar prop, anticipate Jabiru 3300 to have greater static  thrust than Rotax 912 and slightly lower than 912S with a prop trimmed for 5800  engine RPM. Prop experiencing 2387 RPM & 217 Lbf Ft torque. Note that the  Jabiru 3300 would have 205 Lbf Ft of torque at that 2387 prop RPM. Should trim  prop for Jab optimum 2750 RPM and torque of 209 Lbf Ft. Mario Gaulin, Ontario,  Canada. 29 Oct 2003.

     	  Quote: 	
		  [b]

gburdett

Joined: 05 Aug 2008
Posts: 13

Posted: Wed Oct 15, 2008 5:05 am Post subject: Re: Zenith CH750 Detail Pictures

Bob Collins



I also built the rudder in September and a general conversation at the factory day was that a larger rudder would look better. Caleb has said it is not needed and that it adds area, etc. Nonetheless, it is a hope that they will continue to develop the rudder for looks( I would simply build another), give the stab the authority it needs at low speeds in the flare, and produce additional fairing for the stab. While they're at it, a fiberglass cap for the rudder and and better detail around the door would also improve looks. It is experimental, and when I get that far, it's up to me-so we'll see.



Gary Burdett

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