---------------------------------------------------------- Zenith-List Digest Archive --- Total Messages Posted Sat 04/03/04: 19 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 03:13 AM - Re: belt and suspenders (alex trent) 2. 06:58 AM - Re: Re: belt and suspenders (Ray Montagne) 3. 07:38 AM - Re: Re: belt and suspenders (Wayne McIntosh) 4. 07:46 AM - Venturi (Andrew SanClemente) 5. 07:47 AM - Re: Re: belt and suspenders (Ray Montagne) 6. 08:15 AM - Re: Venturi (Thilo Kind) 7. 08:31 AM - Re: Venturi (r.p.reynolds) 8. 08:39 AM - Woodcomp Props (r.p.reynolds) 9. 09:34 AM - Re: Woodcomp Props--pitch setting (Leo J. Corbalis) 10. 09:49 AM - Venturi (Robert Schoenberger) 11. 11:02 AM - Re: Venturi (Thilo Kind) 12. 03:10 PM - Re: Re: belt and suspenders (Thomas F Marson) 13. 03:18 PM - Re: Woodcomp Props (Thomas F Marson) 14. 03:49 PM - Re: Re: belt and suspenders (Ray Montagne) 15. 03:54 PM - Re: Venturi (Thomas F Marson) 16. 05:23 PM - CH-640 Aileron tips. (Jeff Paden) 17. 06:20 PM - Edge spacing for bolts and rivets... (Bima, Martin) 18. 06:43 PM - Inductive tach pick-up... (Bima, Martin) 19. 06:50 PM - Re: Venturi (Brett Ray) ________________________________ Message 1 _____________________________________ Time: 03:13:23 AM PST US From: "alex trent" Subject: Zenith-List: Re: belt and suspenders --> Zenith-List message posted by: "alex trent" I believe volts and amps are closely associated when the resistance is constant. If I raise the voltage then the current will also rise. Any electric devices that are running soon won't be because of excessive current. The only thing that may tolerate the voltage without raising the current may be the battery. One should maintain a watch on all instruments including the voltmeter. A means off shutting down the alternator is, in my opinion, a necessary device. (a switched field) It is possible to install an O/V device and a crowbar if desired. Even put in audible as well as visual warnings. All this stuff adds to the complexity. The best safety device is to pay attention to the instruments. I have also seen a/c land wheels up with the horn blaring and the red lights on. > Time: 06:43:31 AM PST US > From: Joemotis@aol.com > Subject: Re: Zenith-List: > > --> Zenith-List message posted by: Joemotis@aol.com > > An in line fuse will not handle an overvoltage condition. Fuses react to amps > over time i.e a slow blow fuse or instantaneously i.e. a standard fuse. A lot > of "Buss" style automotive glass tube fuses are rated to 250 volts. But if > you exceed their current carrying capacity at 12 volts blow they will. > Joe Motis ________________________________ Message 2 _____________________________________ Time: 06:58:58 AM PST US Subject: Re: Zenith-List: Re: belt and suspenders From: Ray Montagne --> Zenith-List message posted by: Ray Montagne On 4/3/04 3:12 AM, "alex trent" wrote: > --> Zenith-List message posted by: "alex trent" > > > I believe volts and amps are closely associated when the resistance is > constant. OHM's law states: E = I X R I = E / R R = E / I Where: E = Voltage I = Current R = Resistance DO NOT ARCHIVE R. Montagne Cupertino, CA ________________________________ Message 3 _____________________________________ Time: 07:38:53 AM PST US From: "Wayne McIntosh" Subject: Re: Zenith-List: Re: belt and suspenders --> Zenith-List message posted by: "Wayne McIntosh" > > > I believe volts and amps are closely associated when the resistance is > constant. If I raise the voltage then the current will also rise. No it will not as long as the resistance remains constant actually the current flow will decrease. Wayne McIntosh Lafayette IN ________________________________ Message 4 _____________________________________ Time: 07:46:15 AM PST US From: Andrew SanClemente Subject: Zenith-List: Venturi --> Zenith-List message posted by: Andrew SanClemente Having scoured the archives, I've noticed almost everyone using a Venturi disappointed with its performance, independent of location. One gentleman did remark that mounting underneath fuselage behind exhaust he was getting good vacuum. My radiator precludes this location. Is it a completely insane idea to mount 2 venturi's to drive 2 gyro instruments? (I understand the penalties incurred aesthetically and with regards to drag). >From what I've read a single 9" seems to pull between 2-4" on average on 601's so with 2 of them theoretically it should get sufficient suction (or am I missing some formula with regards to airflow that makes this untrue?) Thanks for replies in advance Andrew 601 HDS Stratus EA-81 ________________________________ Message 5 _____________________________________ Time: 07:47:49 AM PST US Subject: Re: Zenith-List: Re: belt and suspenders From: Ray Montagne --> Zenith-List message posted by: Ray Montagne On 4/3/04 7:38 AM, "Wayne McIntosh" wrote: > --> Zenith-List message posted by: "Wayne McIntosh" > > >> >> >> I believe volts and amps are closely associated when the resistance is >> constant. If I raise the voltage then the current will also rise. > > No it will not as long as the resistance remains constant actually the > current flow will decrease. > Wayne McIntosh Lafayette IN > Actually the current will increase as voltage increases given a constant resistance. Again, Ohms law states: I = E / R Given a votage of 10 volts and a resistance of 10 ohms, the current would be on amp: 10 volts / 10 ohms = 1 amp Raising the voltage, say to 20 volts, yields an increase in current: 20 volts / 10 ohms = 2 amps DO NOT ARCHIVE R. Montagne Cupertino, CA ________________________________ Message 6 _____________________________________ Time: 08:15:58 AM PST US From: "Thilo Kind" Subject: Re: Zenith-List: Venturi --> Zenith-List message posted by: "Thilo Kind" Hi Andrew, I tried the venturi with only one gyro. Didn't work well - ther was only enough vacuum during straight and level at cruise speed. Now I have the electric gyro and am quite happy with that thing. Happy flying Thilo Kind ----- Original Message ----- From: "Andrew SanClemente" Subject: Zenith-List: Venturi > --> Zenith-List message posted by: Andrew SanClemente > > Having scoured the archives, I've noticed almost everyone using a > Venturi disappointed with its performance, independent of location. > One gentleman did remark that mounting underneath fuselage behind > exhaust he was getting good vacuum. My radiator precludes this > location. > Is it a completely insane idea to mount 2 venturi's to drive 2 gyro > instruments? > (I understand the penalties incurred aesthetically and with regards > to drag). > > >From what I've read a single 9" seems to pull between 2-4" on average > on 601's so with 2 of them theoretically it should get sufficient > suction (or am I missing some formula with regards to airflow that > makes this untrue?) > > Thanks for replies in advance > > Andrew > 601 HDS Stratus EA-81 > > ________________________________ Message 7 _____________________________________ Time: 08:31:20 AM PST US From: "r.p.reynolds" Subject: Re: Zenith-List: Venturi --> Zenith-List message posted by: "r.p.reynolds" Dear Andrew, I am also having trouble getting the Venturi to give me enough Suck. I have a 601 UL I have tried Lowering the Venturi about 6 inches from the bottom of the fus but still no improvement. When I run one gauge with the venturi the needle on the vacuum gauge goes off the clock!. But I only get max 4 inches of mercury with both gauges on line. Regards Paul UK Aircraft flown 26 hours. ----- Original Message ----- From: "Andrew SanClemente" Subject: Zenith-List: Venturi > --> Zenith-List message posted by: Andrew SanClemente > > Having scoured the archives, I've noticed almost everyone using a > Venturi disappointed with its performance, independent of location. > One gentleman did remark that mounting underneath fuselage behind > exhaust he was getting good vacuum. My radiator precludes this > location. > Is it a completely insane idea to mount 2 venturi's to drive 2 gyro > instruments? > (I understand the penalties incurred aesthetically and with regards > to drag). > > >From what I've read a single 9" seems to pull between 2-4" on average > on 601's so with 2 of them theoretically it should get sufficient > suction (or am I missing some formula with regards to airflow that > makes this untrue?) > > Thanks for replies in advance > > Andrew > 601 HDS Stratus EA-81 > > ________________________________ Message 8 _____________________________________ Time: 08:39:31 AM PST US From: "r.p.reynolds" Subject: Zenith-List: Woodcomp Props --> Zenith-List message posted by: "r.p.reynolds" Good Day to all Zenair Fans Does anyone know what is the Max pitch which can be set on a Woodcomp 3 blade prop engine is a 912 100HP. The aircraft has a fantastic take off performance, I would like to reduce the revs a bit in the cruise. At 5000 revs the Aircraft is doing 95 Knots. Regards Paul UK 601UL 26 hours in the air so far. ________________________________ Message 9 _____________________________________ Time: 09:34:06 AM PST US From: "Leo J. Corbalis" Subject: Re: Zenith-List: Woodcomp Props--pitch setting --> Zenith-List message posted by: "Leo J. Corbalis" If you have a ground adjustable prop, Measure the current setting and then increase it by 2 degrees. Test fly, try again until climb really sucks, then decrease pitch in 1 degree steps until you get the best comprimise setting. This is the same for all ground adjustable props. If you set the maximum possible pitch angle you may not get enough speed to takeoff because you need to get the maximum rated rpm to get full power. Leo Corbalis> ________________________________ Message 10 ____________________________________ Time: 09:49:45 AM PST US From: "Robert Schoenberger" Subject: Zenith-List: Venturi --> Zenith-List message posted by: "Robert Schoenberger" Thilo . . . What size venturi were you using and with what model plane? Robert Schoenberger 701 --> Zenith-List message posted by: "Thilo Kind" Hi Andrew, I tried the venturi with only one gyro. Didn't work well - ther was only enough vacuum during straight and level at cruise speed. Now I have the electric gyro and am quite happy with that thing. ________________________________ Message 11 ____________________________________ Time: 11:02:39 AM PST US From: "Thilo Kind" Subject: Re: Zenith-List: Venturi --> Zenith-List message posted by: "Thilo Kind" Hi Robert, I have the 601 HDS (with Rotax 912). Venturi was a 4' if memory serves me right. The venturi was positioned underneath the cowling / firewall. Thilo Kind ----- Original Message ----- From: "Robert Schoenberger" Subject: Zenith-List: Venturi > --> Zenith-List message posted by: "Robert Schoenberger" > > Thilo . . . What size venturi were you using and with what model plane? Robert Schoenberger 701 > > > --> Zenith-List message posted by: "Thilo Kind" > > Hi Andrew, > > I tried the venturi with only one gyro. Didn't work well - ther was only > enough vacuum during straight and level at cruise speed. Now I have the > electric gyro and am quite happy with that thing. > > ________________________________ Message 12 ____________________________________ Time: 03:10:25 PM PST US From: "Thomas F Marson" Subject: Re: Zenith-List: Re: belt and suspenders --> Zenith-List message posted by: "Thomas F Marson" In a DC circuit if the resistance is held constant and the voltage is raised the current will rise. In a DC circuit if the voltage is held constant and the resistance is decreased the current will rise. I am describing simple OHMs law for Direct Current ( DC). Tom Marson ----- Original Message ----- From: "Wayne McIntosh" Subject: Re: Zenith-List: Re: belt and suspenders > --> Zenith-List message posted by: "Wayne McIntosh" > > > > > > > I believe volts and amps are closely associated when the resistance is > > constant. If I raise the voltage then the current will also rise. > > No it will not as long as the resistance remains constant actually the > current flow will decrease. > Wayne McIntosh Lafayette IN > > ________________________________ Message 13 ____________________________________ Time: 03:18:03 PM PST US From: "Thomas F Marson" Subject: Re: Zenith-List: Woodcomp Props --> Zenith-List message posted by: "Thomas F Marson" Most people I talk to who have good experience with the 912S like to cruise at about 75% power and in level flight have engine RPms right around 5000. In order to give any advice we need to know what percentage of of total hp you are at when yu in cruise at 5000 rpm. Also and maybe more importantly when you are at full throttle in best rate of climb (VY) what is your rpm? Also when your plane is in level flight at full throttle what is your RPM? Tom IN Wis Good Day to all Zenair Fans > > Does anyone know what is the Max pitch which can be set on a Woodcomp 3 blade prop engine is a 912 100HP. > The aircraft has a fantastic take off performance, I would like to reduce the revs a bit in the cruise. At 5000 revs the Aircraft is doing 95 Knots. > > ________________________________ Message 14 ____________________________________ Time: 03:49:01 PM PST US Subject: Re: Zenith-List: Re: belt and suspenders From: Ray Montagne --> Zenith-List message posted by: Ray Montagne On 4/3/04 3:09 PM, "Thomas F Marson" wrote: > --> Zenith-List message posted by: "Thomas F Marson" > > In a DC circuit if the resistance is held constant and the voltage is raised > the current will rise. > > In a DC circuit if the voltage is held constant and the resistance is > decreased the current will rise. > >> No it will not as long as the resistance remains constant actually the >> current flow will decrease. >> Wayne McIntosh Lafayette IN >> >> I absolutely agree with what is said in this post. The previous post did not say the same thing which is why I offered the correction. DO NOT ARCHIVE R. Montagne Cupertino CA ________________________________ Message 15 ____________________________________ Time: 03:54:00 PM PST US From: "Thomas F Marson" Subject: Re: Zenith-List: Venturi --> Zenith-List message posted by: "Thomas F Marson" If you have larger enough lines and no leaks and clear instrument filters a 4 inch venturi will dependably give enough vacume to run an artificial Horizon or DG. In fact it can run both at 100 mph. A 2 inch will run an turn and bank (or turn coordinator as it is now called). You may have a leak or leaks, bad instrument or dirty instrument filters. Tony Binglis SportPlane Construction Techniques has good coverage on this. Tom inWis. ----- Original Message ----- From: "r.p.reynolds" Subject: Re: Zenith-List: Venturi > --> Zenith-List message posted by: "r.p.reynolds" > > Dear Andrew, > I am also having trouble getting the Venturi to give me enough Suck. > I have a 601 UL I have tried Lowering the Venturi about 6 inches from the > bottom of the fus but still no improvement. > When I run one gauge with the venturi the needle on the vacuum gauge goes > off the clock!. But I only get max 4 inches of mercury with both gauges on > line. > > ________________________________ Message 16 ____________________________________ Time: 05:23:33 PM PST US From: "Jeff Paden" Subject: Zenith-List: CH-640 Aileron tips. --> Zenith-List message posted by: "Jeff Paden" Well, my building has been set back a couple of days since I have been fighting with the Aileron tips. All the rest of the parts in the kit are shipped preformed, however the tips are shipped as just a flat part and I have to form it to fit the complex shape of the aileron tip. So far I have three scrap tips and I will keep trying until I find a way to make it correctly. If anyone reading this has an idea of how to properly do this then I would sure like to hear from you! Just email me at jeffpaden@madbbs com with any comments or suggestions. Thank you all for your help Jeff Paden CH-640 builder 90% complete ________________________________ Message 17 ____________________________________ Time: 06:20:50 PM PST US Subject: Zenith-List: Edge spacing for bolts and rivets... From: "Bima, Martin" --> Zenith-List message posted by: "Bima, Martin" Here's a thought... The edge spacing guidelines is there to make sure we don't rip a bolt through the sheet metal and out the edge. The 2xD provides the LOAD enough surface SHEAR AREA to remain below the YIELD STRESS. (any of this sound familiar to engineers and techs?). Since the bolts and rivets in the struts are all pulling longitudinally, or 90 degrees from the edge direction, then we can throw the edge spacing requirement away and just cross our fingers when we pull out of a dive at 5.99 G's. Now if I could convince the inspector, all will be well. Martin Bima Winnipeg, Canada "Birthplace of Princess Auto" ________________________________ Message 18 ____________________________________ Time: 06:43:41 PM PST US Subject: Zenith-List: Inductive tach pick-up... From: "Bima, Martin" --> Zenith-List message posted by: "Bima, Martin" I was actually looking at the Stratomaster Ultra. I will correct myself now. It says to wrap the pickup wire around the cable from the coil to the distributor. That's why you have to enter the number of cylinders. Per rev, it will "feel" 3 spikes. For ten revs it will be thirty, for 1000 revs it would be 3000. Seems acurate. Martin Bima Winnipeg, Canada "100 degree summers and 40 below winters" ________________________________ Message 19 ____________________________________ Time: 06:50:06 PM PST US From: "Brett Ray" Subject: Re: Zenith-List: Venturi --> Zenith-List message posted by: "Brett Ray" I just built one out of sheet aluminum. It sets flush on the bottom of the plane and works fine. And you can't see it unless you get on your knees. Brett