Zenith701801-List Digest Archive
Wed 10/15/08 |
Total Messages Posted: 6 |
Today's Message Index:
----------------------
1. 03:47 AM - Re: Zenith CH750 Detail Pictures (kmccune)
2. 05:12 AM - Re: Gross weight? (Dan Stanton)
3. 06:05 AM - Re: Zenith CH750 Detail Pictures (gburdett)
4. 06:10 AM - Re: Re: Gross weight? (Larry)
5. 11:44 AM - Re: Zenith CH750 Detail Pictures (rbjjr)
6. 01:59 PM - Re: Chris Lewis - Please contact me off line (Chris Lewis)
Message 1
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Time: 03:47:53 AM PST US
Subject: Re: Zenith CH750 Detail Pictures
From: "kmccune" <kmccune@somtel.net>
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.
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
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(48)
63
6500
50.9
50.1
2.58
2519
129
27.3
Max 6800 RPM, with lower torque.
Rotax
582(48)
65
6250
54.6
54.0
2.58
2422
139
27.0
Rotax
582(48)
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 @ 2700 RPM
Jabiru
2200
62
2400
135.7
135.0
1
2400
136
14.0
14 L/hr @ cruise (75%)
Rotax
912
81
5800
73.3
72.3
2.273
2552
164
22.8
Max 5 min @ 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.
> [b]
--------
Mark Twain: Twenty years from now you will be more disappointed by the things that
you didn't do than by the ones you did do. So throw off the bowlines. Sail
away from the safe harbor. Catch the trade winds in your sails. Explore. Dream.
Discover.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p 8861#208861
Message 2
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Time: 05:12:51 AM PST US
Subject: Re: Gross weight?
From: "Dan Stanton" <daniel_stanton1@comcast.net>
Larry,
I just bought a drive system from GP and it had the serpentine type belts, not
cog.
--------
Dan Stanton
801 125 hrs.
701 75% done
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p 8864#208864
Message 3
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Time: 06:05:39 AM PST US
Subject: Re: Zenith CH750 Detail Pictures
From: "gburdett" <gburdett1@verizon.net>
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
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p 8870#208870
Message 4
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Time: 06:10:30 AM PST US
From: Larry <lrm@skyhawg.com>
Subject: Re: Gross weight?
They must have just changed. The catalog I have shows cog. Glad they
did. Larry
Dan Stanton wrote:
>
> Larry,
> I just bought a drive system from GP and it had the serpentine type belts, not
cog.
>
> --------
> Dan Stanton
> 801 125 hrs.
> 701 75% done
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p 8864#208864
>
>
>
> ------------------------------------------------------------------------
>
>
> Checked by AVG - http://www.avg.com
>
>
Message 5
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Time: 11:44:01 AM PST US
Subject: Re: Zenith CH750 Detail Pictures
From: "rbjjr" <burkeandsusan@verizon.net>
Thanks Bob. Yes I was responding to you.
I seemed to have had out of date plans as well but Caleb has been very helpful
in working with me on ways to replace my spar with the thicker one. I'd still
be interested in what your workshop instructor says to be sure if you are able
to find out from him.
Rgds,
Burke
>
>
> 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
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p 8922#208922
Message 6
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Time: 01:59:00 PM PST US
Subject: Re: Chris Lewis - Please contact me off line
From: "Chris Lewis" <christopherlewis@earthlink.net>
I'll try again.
cl
--------
701 Scratch Builder
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p 8944#208944
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