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.

  #201  
Old 01-23-2021, 07:57 AM
Scott Hersha Scott Hersha is offline
 
Join Date: Jan 2005
Location: Cincinnati, OH
Posts: 1,795
Default

I changed my SIM timing from Advanced, 30*, to fixed, 25* with the dip switch selections. After getting it all internally timed, then timed to the engine at TDC, and torqued in place (150-160 in/lbs!) you are supposed to check the LED flash pattern to make sure you have it set correctly. Well, my flash pattern indicated that I had set 25*, but it was still Advanced. I must have checked my dip switch setting 4 or 5 times. I didn’t want to pull the mag for access to the dip switch plug so I spent an hour getting that little bugger out while still mounted on the engine. With a mirror I was able to determine, for the 6th time, that I had my dip switches in the correct positions for Fixed, 25* timing. So - off came the mag. On my work bench, I checked a few different engine timing settings, and they all worked as far as the timing number goes (20*, 25*, 30*, etc), but all of them indicated Advanced. The #1 dip switch controls the Fixed/advanced functionality, and it is apparently stuck in the open (OFF) position. The SureFly tech rep talked me through this. Whenever you changed one of those dip switch settings, you have to flash power on the timing terminal in order for it to take effect, which I had done. The tech rep told me that without a manifold pressure line attached, it would just default to fixed timing. That didn’t make sense to me, especially since they want you to leave the MAP port uncapped when in Fixed timing. The mag advances the timing based on RPM & MP that it sees on that port, like the others do, and it just seems like I would now be sensing ambient under the cowl pressure. As I climb and the ambient pressure dropped below 25”, there should be some advance. The mag is still indicating, via the LED flash pattern, that it is electronically operating in the Advanced mode. If I changed the #1 dip switch to OFF, I still got the same flash pattern.
Anyway - sorry for the long description, I’m just trying to get this straight in my feeble mind. The mag is on it’s way to Granbury, TX for repair. If you make changes on yours, make sure you flash that timing terminal with the mag grounded. You can use your main power lead for this, or an external battery. Taking the threaded cap plug out to access the dip switches while mounted on the engine wasn’t worth it for me. It is made out of nickel plated brass with a too wide slot that is easily damaged, especially if you are removing it after use. The thread locker they recommend using makes it difficult.
__________________
SH
RV6/2001 built/sold 2005
RV8 Fastback/2008 built/sold 2015
RV4/bought 2016/sold/2017
RV8/2018 built/Sold(sadly)
RV4/bought 2019 Flying
Cincinnati, OH/KHAO
JAN2021

Last edited by Scott Hersha : 01-23-2021 at 08:00 AM.
Reply With Quote
  #202  
Old 01-23-2021, 08:40 AM
pecanflyboy pecanflyboy is offline
 
Join Date: Nov 2011
Location: Granbury, Texas
Posts: 135
Default

Quote:
Originally Posted by Scott Hersha View Post
The tech rep told me that without a manifold pressure line attached, it would just default to fixed timing. That didn’t make sense to me, especially since they want you to leave the MAP port uncapped when in Fixed timing. The mag advances the timing based on RPM & MP that it sees on that port, like the others do, and it just seems like I would now be sensing ambient under the cowl pressure. As I climb and the ambient pressure dropped below 25”, there should be some advance.
Scott,
Your understanding it correct. If the unit is set for variable timing, with the MP line exposed to ambient pressure, it will advance when that pressure drops below 25".

Also, the manual states that when you install the unit on the engine, the timing post must be engergized to set the timing. This will take care of "flashing" the unit to the new DIP settings.

The DIP switches are potted in epoxy pretty and very durable if not abused. The bench test units have been switched hundreds of times. The only time they have seen them fail is when a user is trying to change the settings with the SIM still installed on the engine. This is usually tried with a metal pick and a mirror, sometimes resulting in damage to the switch cluster. It's pretty obvious when the unit is inspected upon return.

$$

Last edited by pecanflyboy : 01-23-2021 at 12:49 PM. Reason: Added information
Reply With Quote
  #203  
Old 01-23-2021, 02:09 PM
Scott Hersha Scott Hersha is offline
 
Join Date: Jan 2005
Location: Cincinnati, OH
Posts: 1,795
Default

By “flashing” I meant energizing the timing terminal as you stated, and that’s what I did, and also what the tech rep said to do. The only time I changed dip switch settings was with the mag off the engine and I had only done that once when trying to switch from advanced to fixed, and that was done on my workbench. The only reason I took a look while still mounted on the engine was to see if I had my settings right. It would have been impossible to change those switches while mounted in my installation. Plus, I’m pretty sure I wouldn’t have been able to get that threaded plug reinstalled correctly. All switches performed they way they are supposed to, except dip switch #1. I guess I got the one in a thousand that is faulty. The SureFly rep gave me an RMA# and said to send it in
__________________
SH
RV6/2001 built/sold 2005
RV8 Fastback/2008 built/sold 2015
RV4/bought 2016/sold/2017
RV8/2018 built/Sold(sadly)
RV4/bought 2019 Flying
Cincinnati, OH/KHAO
JAN2021

Last edited by Scott Hersha : 01-23-2021 at 02:13 PM.
Reply With Quote
  #204  
Old 01-26-2021, 03:36 PM
Scott Hersha Scott Hersha is offline
 
Join Date: Jan 2005
Location: Cincinnati, OH
Posts: 1,795
Default

Yep..... I had the 1 in a thousand with a bad switch. SureFly called me today to say that the #1 switch was indeed bad. I think this was a big surprise to them, because maybe they havenít seen this before. Itís important to them because this is a certified unit. I got STC paperwork with mine, so I assume it is the same as a certified unit. This is a good company. I purchased this SIM in November of 2019, and Iíve been flying it since January 2020. I donít know what the warranty period is, but they are sending me a new SIM4. The switch is surface mounted on a PCB, and maybe they canít just replace that board. At any rate, I am happy with the product, and very satisfied with the company support.
__________________
SH
RV6/2001 built/sold 2005
RV8 Fastback/2008 built/sold 2015
RV4/bought 2016/sold/2017
RV8/2018 built/Sold(sadly)
RV4/bought 2019 Flying
Cincinnati, OH/KHAO
JAN2021
Reply With Quote
  #205  
Old 02-01-2021, 01:46 AM
nomocom's Avatar
nomocom nomocom is offline
 
Join Date: Jun 2009
Location: Caldwell ID
Posts: 264
Default 50hr report, 3 out of 5 stars.

O-360A1A Surefly right side, 25d BTDC fixed timing, Left side a Bendix with impulse coupling.

Likes- avoid the hassle and cost of the 500hr mag IRAN, install was simple, the SIM allows a smidge more leaning.

Dislikes- the install and ops manuals left out two important points. #1 the vacuum port cap problem, don't plug it off, and #2 Inflight mag checks can abuse your exhaust system. #1 I found out when talking to the factory about another matter, and #2 was discovered when doing high power inflight mag tests. The SIM takes a split second to boot up when the P-lead goes from grounded to open. 1/10 of a second doesn't seem long, but it is long enough to push combustible mix into the exhaust, and then when the SIM does wake up. BOOM! Last July, Bill from Surefly reported there was a fix in the works to make the boot up 2 milliseconds. That would be similar to a magneto.
# 3 dislike, kickbacks, so I'm back to starting on the left mag only (impulse coupling). After changing my routine to both, I had a few kickbacks, probably associated with a weak battery at the time, but the impulse coupling with the 25d lag has never done that. Why? Maybe the effective timing is moved forward with both mags firing or a maybe a more powerful spark from the SIM. The starting TDC problem is discussed in another thread. Short version- a few degrees after TDC minimizes the risk of kickback and doesn't seem to have any downside. A workaround to get later timing is described in the other thread. However, it would be better if the ATDC starting timing were baked in. The workaround to get ATDC timing is not in the certified aircraft installation instructions so it is really only available to experimental aircraft.

Would I buy another? Probably. Bill was helpful and honest about the SIM, but even with great customer service, a mag overhaul would have been less hassle. So, to tip the scales in favor, we've got to avoid future magneto IRAN's.
Surefly will likely improve their product if they can work the changes through the certification system. If they can do that, there is even more to like, it goes from a 3 star review to 4 or 5.
__________________
Stan
1990 RV-3 (now apart, upgrades in the works)
1959 C172 O-360
Reply With Quote
  #206  
Old 02-01-2021, 07:25 AM
DanH's Avatar
DanH DanH is offline
 
Join Date: Oct 2005
Location: 08A
Posts: 9,887
Default

Quote:
Originally Posted by nomocom View Post
...Inflight mag checks can abuse your exhaust system......The SIM takes a split second to boot up when the P-lead goes from grounded to open. 1/10 of a second doesn't seem long, but it is long enough to push combustible mix into the exhaust, and then when the SIM does wake up. BOOM! Last July, Bill from Surefly reported there was a fix in the works to make the boot up 2 milliseconds. That would be similar to a magneto.
This inflight test was a full ignition shutdown, i.e. the magneto was grounded prior to switching the Surefly off, then on?

Or are you using a left-right-both key switch?
__________________
Dan Horton
RV-8 SS
Barrett IO-390
Reply With Quote
  #207  
Old 02-01-2021, 07:53 AM
pecanflyboy pecanflyboy is offline
 
Join Date: Nov 2011
Location: Granbury, Texas
Posts: 135
Default

Quote:
Originally Posted by Scott Hersha View Post
Yep..... I had the 1 in a thousand with a bad switch. SureFly called me today to say that the #1 switch was indeed bad. I think this was a big surprise to them, because maybe they havenít seen this before. Itís important to them because this is a certified unit. I got STC paperwork with mine, so I assume it is the same as a certified unit. This is a good company. I purchased this SIM in November of 2019, and Iíve been flying it since January 2020. I donít know what the warranty period is, but they are sending me a new SIM4. The switch is surface mounted on a PCB, and maybe they canít just replace that board. At any rate, I am happy with the product, and very satisfied with the company support.
Good to hear they were able to replace the unit under warranty. Regardless of experimental or certified, everyone gets an STC'd unit. No differences in the product. The warranty is for two years.

Because the life of the product is relatively young, Surefly is not rebuilding or overhauling units. So, if you have a warranty issue, they will typically send you a new unit. This will eventually change as the product ages.

Happy flying!

$$
Reply With Quote
  #208  
Old 02-01-2021, 08:21 AM
pecanflyboy pecanflyboy is offline
 
Join Date: Nov 2011
Location: Granbury, Texas
Posts: 135
Default

Quote:
Originally Posted by nomocom View Post
O-360A1A Surefly right side, 25d BTDC fixed timing, Left side a Bendix with impulse coupling.

Likes- avoid the hassle and cost of the 500hr mag IRAN, install was simple, the SIM allows a smidge more leaning.

Dislikes- the install and ops manuals left out two important points. #1 the vacuum port cap problem, don't plug it off, and #2 Inflight mag checks can abuse your exhaust system. #1 I found out when talking to the factory about another matter, and #2 was discovered when doing high power inflight mag tests. The SIM takes a split second to boot up when the P-lead goes from grounded to open. 1/10 of a second doesn't seem long, but it is long enough to push combustible mix into the exhaust, and then when the SIM does wake up. BOOM! Last July, Bill from Surefly reported there was a fix in the works to make the boot up 2 milliseconds. That would be similar to a magneto.
# 3 dislike, kickbacks, so I'm back to starting on the left mag only (impulse coupling). After changing my routine to both, I had a few kickbacks, probably associated with a weak battery at the time, but the impulse coupling with the 25d lag has never done that. Why? Maybe the effective timing is moved forward with both mags firing or a maybe a more powerful spark from the SIM. The starting TDC problem is discussed in another thread. Short version- a few degrees after TDC minimizes the risk of kickback and doesn't seem to have any downside. A workaround to get later timing is described in the other thread. However, it would be better if the ATDC starting timing were baked in. The workaround to get ATDC timing is not in the certified aircraft installation instructions so it is really only available to experimental aircraft.

Would I buy another? Probably. Bill was helpful and honest about the SIM, but even with great customer service, a mag overhaul would have been less hassle. So, to tip the scales in favor, we've got to avoid future magneto IRAN's.
Surefly will likely improve their product if they can work the changes through the certification system. If they can do that, there is even more to like, it goes from a 3 star review to 4 or 5.
#2 Mag check backfires are mentioned in the FAQ of the Surefly website. The issue is with Bendix style ignition swiches that are positioned "OFF-R-L-BOTH-START(may or may not). Whether new or old, some of these switches will ground both ignitions momentarily as there are switched between Right and Left. This is a defect in the switch. From the Surefly website:

"Why does the engine stumble during mag check?

On some aircraft there is a slight engine stumble when doing a mag check. We have discovered that some mag switches actually ground both ignition systems in the transition between Left and Right positions. The SureFly Ignition Module requires a few milliseconds to power up after being tuned on. This only occurs on a small percentage of aircraft. If you are one of the lucky ones, stay tuned as we are working on a solution.

We have found that turning the ignition switch slowly between positions masks this issue on most aircraft. (edit: This worked for me and most I've talked to with this issue)

Another remedy to mask the issue is to reduced power to idle before returing to "Both". Sequence as follows - Both, Left, Right, reduce power to idle and move back to Both.

Please make sure your ACS aircraft ignition switch is in compliance with AD 93-05-06."

#3 If you have a weak battery, poorly grounded engine or starter, or corrosion in the starter relay or cable terminals, you can get a backfire during the start. It has nothing to do with the accuracy of the SIM timing during start, and will not be corrected by timing several degrees after TDC. There fix is usually to check the health of your electrical system (weak battery in your case).

It has to do with the system voltage dropping below the required voltage (8.5VDC) for the SIM to operate. I believe the SIM charges the coils as the engine approaches TDC on compression. If the system voltage drops below the operating voltage of the SIM, it will shut down and it is possible for the field to collapse and a spark to be released before TDC. You will see this as the starter struggles to get the blade over compression, and the engine kicks back. Check the voltage at the starter teminal when the starter is engaged to check the health of your electrical system.
Reply With Quote
  #209  
Old 02-01-2021, 08:55 AM
Sam Buchanan's Avatar
Sam Buchanan Sam Buchanan is offline
been here awhile
 
Join Date: Dec 2004
Location: North Alabama
Posts: 4,394
Default

I have toggle mag switches and have never seen the "backfire or stumble" issue during run-up or inflight mag tests. Either the mag or SureFly is firing at all times. My SureFly is static timed at 0* TDC, fixed timing @ 25*, the remaining Slick mag is non-impulse.
__________________
Sam Buchanan
RV-6
Fokker D.VII replica

Last edited by Sam Buchanan : 02-01-2021 at 11:08 AM.
Reply With Quote
  #210  
Old 02-01-2021, 10:42 AM
nomocom's Avatar
nomocom nomocom is offline
 
Join Date: Jun 2009
Location: Caldwell ID
Posts: 264
Default Inflight mag check

Quote:
Originally Posted by DanH View Post
This inflight test was a full ignition shutdown, i.e. the magneto was grounded prior to switching the Surefly off, then on?

Or are you using a left-right-both key switch?
The off-RIGHT-left-both switch. I think what is happening is when I turn from both to Right, the switch is Left only (right grounded) long enough that the Sim has to reboot by the time I get to right. I admit, I am not quick on the switch, as years ago I made the rookie mistake, going too far, all the way to off.

Iím glad to hear the literature or at least the FAQ has been updated to include the warning. Last summer when I discovered this, I encouraged Bill to communicate a warning to customers. I also wrote Mike Busch, as he is the advocate of mag stress tests that convinced me years ago to make the inflight tests routine.

Yes, separate p-lead switches would make this a none issue.

My method now is switch to the SIM with the power pulled back. Might add 5 seconds to the test, which isnít a big deal, but it is a quirk and in that regard, it is different than running a mag. I donít think Iíd put one on the right side of a rental airplane until the sim bootup is quicker. Installed on the left side might not be an issue at all given the switch design.

Last summer Bill reported the units had a 1/10 second boot. He said they were getting 2/1000 sec bootup in the pipeline. It sounded like a FAA hurdle. I donít know what theyíre shipping now. If the offered a firmware update, Iíd do it.

I looked at the FAQ.... at least in my configuration, that isnít helpful, they have it backwards. Power needs to be low before going to right only, since Iím turning through left only which has shut the SIM down. Once Iíve brought power back on and tested the SIM, going to left or both ungrounds the bendix which comes on line immediately so I do that without reducing power.
__________________
Stan
1990 RV-3 (now apart, upgrades in the works)
1959 C172 O-360
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 10:19 PM.


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.