VansAirForceForums  
Home > VansAirForceForums

- POSTING RULES
- Donate yearly (please).
- Advertise in here!

- Today's Posts | Insert Pics


Go Back   VAF Forums > Avionics / Interiors / Fiberglass > Electrical Systems
Register FAQ Members List Calendar Today's Posts

Reply
 
Thread Tools Search this Thread Display Modes
  #21  
Old 11-29-2014, 07:37 AM
Sam Buchanan's Avatar
Sam Buchanan Sam Buchanan is online now
been here awhile
 
Join Date: Dec 2004
Location: North Alabama
Posts: 4,301
Default But not on the control stick!

Even though I like the starter push button arrangement, I have seen a few cases where the starter button is located on the control stick. In my opinion, this is a very bad idea. I think it is much better for the button to be located out of the usual flow of motions so it takes a deliberate action to engage it. On my panel it is located at the upper left corner away from any other switches. I also have a 'starter light' to indicate a stuck starter contactor.
__________________
Sam Buchanan
RV-6
Fokker D.VII replica
Reply With Quote
  #22  
Old 11-29-2014, 08:06 AM
Toobuilder's Avatar
Toobuilder Toobuilder is offline
 
Join Date: Jul 2009
Location: Mojave
Posts: 4,652
Default

A starter button is going on the stick on my Rocket so that I can keep the stick fully back while simultaneously manipulating the throttle/mixture/boost pump during a hot start. On an A model, this is not such a big deal, but a high powered, nose heavy tail dragger requires you to be on your toes, so to speak.

Agreed that the button should not be "casually" accessed, but I plan on installing an arming switch on the panel along with an associated warning light. This will require two separate acts to engage the starter (three, if the switch is guarded). It adds complication, but should ease the cockpit gymnastics.
__________________
WARNING! Incorrect design and/or fabrication of aircraft and/or components may result in injury or death. Information presented in this post is based on my own experience - Reader has sole responsibility for determining accuracy or suitability for use.

Michael Robinson
______________
Harmon Rocket II -SDS EFI
RV-8 - SDS CPI
1940 Taylorcraft BL-65
1984 L39C
Reply With Quote
  #23  
Old 11-29-2014, 09:28 AM
maus92 maus92 is offline
 
Join Date: Nov 2013
Location: Annapolis MD
Posts: 457
Default

Quote:
Originally Posted by Kahuna View Post
Slicks use P-lead and switch to ground.
Starter relay uses +12 to switch relay contactor.

So on each of your toggles, one side of the switch to ground, the other side of the switch to the P-lead. Confirm with ohm meter that each switch is switching to ground with the p-lead OFF the mag. When grounded, the mag will not fire. You will get continuity through the mag on the P-lead which is why you test it with it off the mag.

On starter switch, one side of switch hot +12 to your bus fused. The other side of the switch to the starter relay +12 input to engage coil for starter relay.
The current setup has what appears to be a shielded wire, with the center conductor wired to the P-lead, and the shield conductor wired to the magneto GND screw. On the key switch side, both conductors are wired to tabs on the switch. I am still a bit unclear about the wiring, so bear with me...

To wire the mag switch, I need to connect one side of the switch to the P-lead post, and the other side to the airframe ground? To enable the mag, the circuit should be open, i.e. the switch is in the off position (not connecting to ground,) correct? To disable the mag, the switch is closed ("on" position,) connecting the P-lead to airframe ground, correct?

What is the function of the shield conductor in my current setup? Is it actually shielding potential RF noise? Could / should I use the shield conductor as the ground side of the switch, or should I extend the shield conductor to the FOT behind the panel?

As for the starter switch, I was going to use a button on the stick, but since I'm installing electric roll trim, I'll need that button for another function. The starter interlocking will be handled by VP-X.

Thanks for everyone's input, BTW!
__________________
CA
2000 RV-8A | O-360, SDS CPI, FP, G3X Touch, VP-X, EarthX | Eastern Shore | KESN

Last edited by maus92 : 11-29-2014 at 09:31 AM.
Reply With Quote
  #24  
Old 11-29-2014, 10:07 AM
grubbat's Avatar
grubbat grubbat is offline
 
Join Date: May 2012
Location: Ga
Posts: 662
Default Start switch

I converted my -6 from a push button start switch to a traditional key start. I didn't want that prop spinning because a child or passenger or whomever decided to push the button or lean on it or whatever. My -3 had the push button also and I leaned on it accidentally once working in that cramped cockpit. Thankfully the visitors that day had already left.
Cj

Quote:
Originally Posted by vic syracuse View Post
This is why I even hesitate to try to help any more on this site. There always seems to be a smart answer. All you see is annoyance to other pilots from being blinded by your strobes??? Give me a break. Most checklists actually recommend that the anti-collision lights be on for safety prior to starting. On busy General Aviation ramps with a mix of corporate and GA traffic where there are lots of loading/unloading of passengers and ramp crew around, I find it imperative to get the strobes on, look around and yell very loudly. Yes it is a safety factor. Strobes on do tend to get everyone' attention. If it's at night I pay attention and delay a start so as to not inconvenience someone, and I will in fact turn the strobes off after start and leave the Nav lights on if it is distracting.

As for security, many years ago I had a friend who lost his homebuilt on a ramp at a fly in due to a drunk bystander getting in and starting it up and almost killing people before the aircraft came to a stop. So it's always been on my mind and I try to add a second level of security to the START function.

As for the engines windmilling, it's true for our typical fixed pitch and even constant speed propellers without a feathering function. But not so with the Rotax. They WILL come to a complete stop in flight if there is fuel starvation, and do require starter engagement to get going again. I test this function on every Rotax-equipped airplane I test fly.
__________________
Craig

RV-3 Sold
RV-4 Sold
RV-6a Sold
RV-9 IO-360 CS, Built and Flying
Aerostar 600A, Family Hotrod
Reply With Quote
  #25  
Old 11-29-2014, 10:22 AM
Mike S's Avatar
Mike S Mike S is online now
Senior Curmudgeon
 
Join Date: Sep 2005
Location: Dayton Airpark, NV A34
Posts: 15,420
Default

Quote:
Originally Posted by maus92 View Post
To wire the mag switch, I need to connect one side of the switch to the P-lead post, and the other side to the airframe ground? To enable the mag, the circuit should be open, i.e. the switch is in the off position (not connecting to ground,) correct? To disable the mag, the switch is closed ("on" position,) connecting the P-lead to airframe ground, correct?
Yes, the switch off/open is the mag enabled position.

While using a local airframe ground will work, but the usual way is to ground back to the mag with the shield, as you mention below.

Quote:
Originally Posted by maus92 View Post
What is the function of the shield conductor in my current setup? Is it actually shielding potential RF noise? Could / should I use the shield conductor as the ground side of the switch, or should I extend the shield conductor to the FOT behind the panel?
I would not attach the shield to the FOT (forest of tabs)
__________________
Mike Starkey
VAF 909

Rv-10, N210LM.

Flying as of 12/4/2010

Phase 1 done, 2/4/2011

Sold after 240+ wonderful hours of flight.

"Flying the airplane is more important than radioing your plight to a person on the ground incapable of understanding or doing anything about it."
Reply With Quote
  #26  
Old 11-29-2014, 10:28 AM
maus92 maus92 is offline
 
Join Date: Nov 2013
Location: Annapolis MD
Posts: 457
Default

Quote:
Originally Posted by Mike S View Post
Yes, the switch off/open is the mag enabled position.

While using a local airframe ground will work, but the usual way is to ground back to the mag with the shield, as you mention below.



I would not attach the shield to the FOT (forest of tabs)

Thank you! I think I've got it!

C.
__________________
CA
2000 RV-8A | O-360, SDS CPI, FP, G3X Touch, VP-X, EarthX | Eastern Shore | KESN
Reply With Quote
  #27  
Old 11-29-2014, 11:29 AM
jbDC9 jbDC9 is offline
 
Join Date: Jan 2005
Location: Houston, TX
Posts: 868
Default

Quote:
Originally Posted by vic syracuse View Post
This is why I even hesitate to try to help any more on this site. There always seems to be a smart answer.
Seriously, I didn't mean to sound like a smart-a$$, but was just trying to wrap my head around how keyed start switches and starter thru the strobes add safety and security. Both of the posts I quoted mentioned those two items for safety and security, but then there was no explanation or rationale behind it to explain how, in your opinion, these things enhance safety and security.

Quote:
Originally Posted by vic syracuse View Post
All you see is annoyance to other pilots from being blinded by your strobes???
Well... yes. In my opinion, another ships bright white wingtip strobes on a busy ramp are blinding, annoying, affects my vision, less safe. In your opinion, it's safer for people on the ramp. Everyone is allowed their opinion, so agree to disagree I guess.

I know when you build an airplane you can wire it however you like and that's part of the beauty of experimental aviation, but, I gotta say that I've never flown anything that had the starter wired through the strobes. If I bought a plane wired like that, it'd be the first thing on my list to undo. I'm thinking if you want strobes on for start, turn on the strobes separately. Again, just my opinion. As far as security for drunks and kids, I close the canopy to keep people out, or if I let kids in the seat, I watch them closely.

Fair enough?
__________________
John Bixby
RV-8 QB sn 82030 - 1750 hrs
O-360-A1D/CS/Pmags
Houston, TX

Last edited by jbDC9 : 11-29-2014 at 01:20 PM. Reason: one little oops...
Reply With Quote
  #28  
Old 11-29-2014, 11:47 AM
az_gila's Avatar
az_gila az_gila is offline
 
Join Date: Jan 2005
Location: 57AZ - NW Tucson area
Posts: 10,011
Smile

"...I converted my -6 from a push button start switch to a traditional key start. I didn't want that prop spinning because a child or passenger or whomever decided to push the button or lean on it or whatever..."

I thought of that, but it does take two bad actions to get the prop to spin, Master On and Press Starter button.

I think a modern kid would just as likely turn a key switch as press a button...
__________________
Gil Alexander
EAA Technical Counselor, Airframe Mechanic
Half completed RV-10 QB purchased
RV-6A N61GX - finally flying
Grumman Tiger N12GA - flying
La Cholla Airpark (57AZ) Tucson AZ
Reply With Quote
  #29  
Old 11-29-2014, 01:43 PM
gasman gasman is offline
 
Join Date: Mar 2007
Location: Sonoma County
Posts: 3,821
Default

Quote:
Originally Posted by az_gila View Post
"...I converted my -6 from a push button start switch to a traditional key start. I didn't want that prop spinning because a child or passenger or whomever decided to push the button or lean on it or whatever..."

I thought of that, but it does take two bad actions to get the prop to spin, Master On and Press Starter button.

I think a modern kid would just as likely turn a key switch as press a button...
Being a smart a$$ here..... I just have to say that my last certified A/C, a Warrior did come with a removable key in the starter switch.

I hate key switches..... they are too complicated for what have to do. And as they wear out, they can become dangerous and fail in the HOT position.

If you are going to display your plane where the switches might get fiddled with, then make a lockable cover to protect important switches.
__________________
VAF #897 Warren Moretti
2019 =VAF= Dues PAID
Reply With Quote
  #30  
Old 11-29-2014, 02:04 PM
jrs14855 jrs14855 is offline
 
Join Date: Apr 2008
Location: Lake Havasu City AZ
Posts: 2,393
Default Switch

General opinion from other sources agrees with what I have always believed: rotating beacon, if installed, on for engine start. Strobe lights on when cleared for takeoff, off when clearing runway after landing.
If you operate stobe lights, especially at night, for start and taxi, be prepared for a LOT of flak from those who know better.
Regarding mag grounding, I have not seen mention that if you have one impulse and one non impulse mag, the non impulse MUST be off for start. This happens automatically with properly wired key switch. With toggles if you forget this you may very well trash your starter.

Mag wire shielding has been discussed many times on this forum. Only the mag end of shielding should be grounded, the switch end should be open.
Reply With Quote
Reply



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 08:11 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.