VansAirForceForums  
Home > VansAirForceForums

-POSTING RULES
-Advertise in here!
- Today's Posts | Insert Pics

Keep VAF Going
Donate methods

Point your
camera app here
to donate fast.

  #1  
Old 05-02-2009, 08:12 AM
N162RV's Avatar
N162RV N162RV is offline
 
Join Date: Feb 2005
Posts: 99
Default 912 alt output

While at SNF I was talking to a technican from Lockwood about the 912 electrical system and he indicated that the output of the altenator was 18.5 amps max and really should stay at no more than 14 amp contast.

Anybody know what the load would be on the -12? Not to mention adding AP and lights....
__________________
Scott Frierson
Picayune,MS
RV6A 160HP
(Sold)
RV12 (sold)
Reply With Quote
  #2  
Old 05-02-2009, 12:13 PM
Bruce Russell Bruce Russell is offline
 
Join Date: Jul 2008
Location: Clayton, GA
Posts: 196
Default

Scott,
I did a quick estimation of the max load from the published equipment list plus 2 AP servos and an LED Position/Strobe setup(AVEO Flash) and came up with a max load of 11.7 amps. I used the max power draw instead of normal, so this number would represent all the equipment operating at max all at once. (Both AP servos moving, transmitting on comm, transponder transmitting, Dynon backup battery charging, strobes flashing, etc.). Fuel pump is not in estimate.

Last edited by Bruce Russell : 05-02-2009 at 01:09 PM.
Reply With Quote
  #3  
Old 05-02-2009, 12:47 PM
flyeyes's Avatar
flyeyes flyeyes is offline
 
Join Date: Jan 2005
Posts: 804
Default

the alternator is running the ignitions as well, isn't it?

Our AirCam has two 912 ULS engines, and is equipped with whelen nav/strobes, Apollo (now garmin) transponder, GX-65 NavComm, ps engineering intercom, an electric turn coordinator, and EIS engine monitors. The landing lights are a pair of Autozone driving lights.

Also two facet pumps which are on in the pattern.

With everything on, voltage will sag at idle. The lights collectively are the biggest draw, but we have two alternators.

On a -12, if considering lights, I would look real hard at LEDs and/or HID.
__________________
James Freeman
RV-8 flying

Last edited by flyeyes : 05-02-2009 at 12:50 PM.
Reply With Quote
  #4  
Old 05-02-2009, 05:11 PM
allbee allbee is offline
 
Join Date: Aug 2006
Location: spokane, wa
Posts: 808
Default

I know my dynon is running on 3 amps, the ap runs on about that. If you have leds you should be ok. Now, if you plan on using a heat vest for winter ops, you might need to turn them off once you land. Seems the rotax standard alt. is not so good at idle. At least mine runs a little lower on the ground. If I have my strobes and heat vest on, the radio sometimes doesn't transmit very well. I just turn one or the other off and I'm good.
Reply With Quote
  #5  
Old 05-03-2009, 07:08 AM
h&jeuropa h&jeuropa is offline
 
Join Date: Jun 2008
Location: Kalamazoo, MI
Posts: 314
Default

Some pilots flying Rotax 9XX engines have learned that the Ducatti regulator is a weak (and expensive) link. Keeping the current load low (say less than 10 amps) helps a lot and providing a flow of cooling air over it is also helpful.

Gilles in France has a very informative article on his website about the Ducatti regulator and his analysis of it.
http://contrails.free.fr/index_en.php

I'm posting this just for information purposes. There are many flying with no problems.

Jim Butcher
Europa XS Rotax 914
Reply With Quote
  #6  
Old 05-03-2009, 07:26 AM
mburch's Avatar
mburch mburch is offline
 
Join Date: Feb 2005
Location: Oregon
Posts: 1,320
Default

Quote:
Originally Posted by h&jeuropa View Post
Gilles in France has a very informative article on his website about the Ducatti regulator and his analysis of it.
http://contrails.free.fr/index_en.php
That's very informative, thanks for posting it. Here is a direct link to the article on his website: http://contrails.free.fr/elec_ducati_en.php

I talked to an LSA owner last week who was highly interested in full electrical system redundancy for his VFR-day-only airplane. Maybe the thing I didn't catch is that the Rotax regulators live hard and short lives?

I wonder if B&C makes a regulator that will work for the Rotax...

mcb
__________________
Matt Burch
RV-7 (last 90%)
http://www.rv7blog.com

Any opinions expressed in this message are my own and not those of my employer.
Reply With Quote
  #7  
Old 05-03-2009, 10:58 AM
h&jeuropa h&jeuropa is offline
 
Join Date: Jun 2008
Location: Kalamazoo, MI
Posts: 314
Default

Matt.

No, B&C doesn't have a replacement regulator. There is a German regulator that is supposedly better but the manufacturer doesn't care to export to the US. Gilles mentions it on his website.

For experimentals, Rotax makes a aux alternator and the B&C vacuum pad alternators will fit. I think the RV12 cooling shroud prevents the fitting of any vacuum pad device.

In my Europa, I devised a crankshaft driven alternator provides about 35 amps and works fine.

Jim Butcher
Europa XS
Rotax 914
Reply With Quote
  #8  
Old 05-03-2009, 01:24 PM
ARPENN ARPENN is offline
 
Join Date: Feb 2009
Location: West Ossipee, NH
Posts: 141
Default

I talked with Van at Sun n' Fun. He showed me the nav/strobe lights proposed for the RV-12. The are AreoLED's, Pulsar exp. model. They draw 2.5 amps @ 12vdc. That is with strobes in use. You can see these at www. AreoLEDS.com.
Reply With Quote
  #9  
Old 05-03-2009, 04:51 PM
the_other_dougreeves the_other_dougreeves is offline
 
Join Date: Jan 2006
Location: Dallas, TX (ADS)
Posts: 2,180
Default

Quote:
Originally Posted by flyeyes View Post
the alternator is running the ignitions as well, isn't it?
Yes and no. The ignitions are run off the alternator, but from separate coils - it's not part of the 12V output.

Remember that output is very much a function of RPM, so with all your avionics and (for example) a 100W landing light, the battery is going to be discharging.

TODR
__________________
Doug "The Other Doug Reeves" Reeves
CTSW N621CT - SOLD but not forgotten
Home Bases LBX, BZN
Reply With Quote
  #10  
Old 05-03-2009, 08:45 PM
Geico266's Avatar
Geico266 Geico266 is offline
 
Join Date: Feb 2005
Location: Huskerland, USA
Posts: 5,864
Default

If you need more power there is a 40 amp alternator available as an add on.
__________________
RV-7 : In the hangar
RV-10 : In the hangar
RV-12 : Built and sold
RV-44 : 4 place helicopter on order.
Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -6. The time now is 04:48 AM.


The VAFForums come to you courtesy Delta Romeo, LLC. By viewing and participating in them you agree to build your plane using standardized methods and practices and to fly it safely and in accordance with the laws governing the country you are located in.