<An open CAS would cause instant shutdown

The Oem guys have such a brilliant solu= tion for=20 this. They know from history that sensors occasionally fail. So they plan on= it.=20 Every revolution they count the number of pulses they saw from the CAS. So=20= normally they see 16 pulses, with 2 breaks. The toothed wheel is missing tee= th=20 at two different spots. One area missing 3 teeth, one missing 4 teeth. So wh= en=20 they see TDC, they say "Hey, how'd the sensor do last revolution? Did we get= 16=20 total pulses? Did we see both a 3 tooth break and a 4 tooth break? No? O= k,=20 then let's use the backup sensor and turn on the fault lamp.

They also measure the integrity of the b= ackup=20 sensor. Pretty simple really, it's just software calculations. Comparing to=20= history. The other cool thing, once you develop this logic, you have it fore= ver.=20 Every future pilot has a ton of extra safety if he needs it. They do this wi= th=20 all critical sensors. Oh, yeah. The other cool thing is that the engine take= s=20 longer to start. So the user doesn't just get fault light, they also get poo= r=20 starting feedback. It's just so brilliant.

There's another important lesson here: T= he KISS=20 concept. So often true, but every once in a while it's a big mistake. Not a g= ood=20 idea to blindly adopt a philosophy. Depends on the details. Two CAS sensors a= re=20 much safer if you compare readings to history, make a decision.

-al wick

----- Original Message -----

From:=20 Tracy

To: Rotary motors in aircr= aft

Sent: Saturday, September 10, 2011 7= :09=20 AM

Subject: [FlyRotary] Re: The good n= ews=20 and the bad news......

I agree that it sounds like electrons Bobby. An open CAS would= =20 cause instant shutdown but I've never heard of a Mazda CAS going bad.=20 Have had reports of bad Subaru CAS's.

BTW, apologies for the confusion about your fuel system. I was= =20 confusing you with Sam Hoskins who also had a recent power failure. = His=20 sounded like fuel system problem but no further word from him.

Tracy Crook

Sent from my iPad

On Sep 3, 2011, at 9:08 AM, "Bobby J. Hughes" <bhughes@qnsi.net> wrote:

What was the system voltage during run up? At what voltage does the= EC2=20 shutdown? Not a likely candidate.

What happens when the CAS circuit goes open? Does the EC2 stop=20 firing?

Will a exhaust blockage of ?% stop the engine completely? Steve's=20= testing showed a partial blockage has a major effect on power. Bill's=20= muffler had to be full of crud for that much to end up back in the engin= e.=20 If the HP2 lower cone was partly intact and came loose then a major bloc= kage=20 is very possible. It would trap all the little pieces that had been=20 collecting in the muffler. My first HP had large chunks of cone still in= tact=20 along with all the little pieces. My second HP seemed more intact when m= y=20 incident occurred. Meaning less large chunks appeared to be loose but pl= enty=20 of the small crud. The outlet cone was loose but more intact. I had hope= d=20 that moving the second muffler to the belly would extend it's life but i= t=20 didn't. In fact it may be more dangerous since the small pieces can't be= =20 discharged as easily. My under cowl muffler was mounted at a downward an= gle.=20 Belly mount is almost flat.

I agree Ed that electrons seem to be the most logical cause but may= be=20 impossible to validate.

Bobby

Sent from my iPad

On Sep 3, 2011, at 10:20 AM, "Ed Anderson" <eanderson@carolina.rr.com= >=20 wrote:

We still don't know (and may never),the caus= es,=20 but Sam's and Bills incidents based on initial information would= =20 appear to me to be two different causes.

Sam's engine kept running - altho= ugh=20 sputtering and producing no power - this to me sounds like a fuel rela= ted=20 problem (possibly vapor lock, possibly something else - could be muffl= er=20 blockage). Bill's on the other hand quit suddenly and without an= y=20 warning - that to me sounds more like an electrical problem - either t= he=20 firing pulses to the injector stopped or the spark stopped. =20

If I were Bill, I would use the EC2's diagno= stic=20 modes to check out each circuit - if one doesn't check out then that i= s=20 probably the answer. If both check OK then more head=20 scratching.

Ed

From: Bobby J. Hughes

Sent: Saturday, September 03, 2011 9:43 AM

To: Rotary motors in aircraft=20

Subject: [FlyRotary] Re: The good news and the bad=20 news......

Bill,

I'm sorry to here about the damage but glad you weren't injured. I= =20 don't know at what percentage of exhaust blockage the engine would sto= p=20 running. Also no reports on the condition of Sam's HP2 muffler. Three=20= aircraft experiencing very similar problems this year is too many. If y= ou=20 have leading / trailing plugs and primary / secondary injectors o= n=20 separate power feeds then it should have kept running. That leaves fue= l=20 delivery (vapor lock), CAS circuit, Controller power, A side computer=20= issue or muffler? I believe Sam did switch controllers during his=20 incident. I didn't and had plenty of time to do so. It's now the secon= d=20 item in my emergency flow.

One common item can be eliminated be removing any muffler that ha= s=20 packing. Especially Hushpower 2 since they are common to all three=20 incidents. I'm assuming Sam's muffler also had loose=20 internals.

Bobby

Sent from my iPad

On Sep 2, 2011, at 11:54 PM, "Bill Eslick" <wgesli= ck@gmail.com>=20 wrote:

I have=20 been holding up reporting this until all the facts are in, but that=20= might never happen, so here we go.

Good news: No injuries. =20

Bad news: I have some work to do.

Photos at:&nb= sp;=20 http://www.tiny9.com/u/2101

On August 16th at 10 AM,=20 I lined up for takeoff at my home airport (3600' paved) into a 5 kno= t=20 headwind. I had just finished changing the oil and filter and=20= plugs. Run-up was fine, so off I went. Approximately=20 mid-field, and a couple of hundred feet in the air, it suddenly and=20= without any warning became very silent.

Hit the big switch wh= ich=20 puts direct battery power to everything engine, but no noise. N= o=20 more time. At this point flying the machine becomes THE=20 priority. Dropped the nose and was amazed to see a little bit o= f=20 runway under the nose! I had fully expected to land in trees,=20= houses or the river, so I dove what seemed like straight down to cap= ture=20 as much runway as possible while (somehow) holding the electric flap= =20 switch long enough to get full flaps (noticed this later). Pul= led=20 probably my best round-out ever - no bounce. Brakes to max and= =20 tail up for weight. I think my sub-concious put it all the way= on=20 the nose to try to prevent going through the fence and down the=20 hill. Wheel skid starts about 200 feet from the stopping=20 point. Skid marks from the wheel pants, cowling and prop run a= bout=20 the last 50 feet. It stopped nose down just off the end. = The=20 tail was still over pavement. Pushed the slider canopy UPHILL,= =20 stepped out and down. Noticed that I was not even scared by th= e=20 whole event. Interesting. Never even considered trying t= o=20 turn around. Pre-thinking that non-option apparently paid=20 off.

More good news. No FAA or NTSB as it was a=20= non-reportable incident. Didn't even bend the gear legs. = =20 Also, my neighbor crashed in a Challenger about 10 minutes earlier a= t=20 the city airport about 10 miles away. The police and rescue ty= pes=20 were headed that way (they had injuries) and were not interested in m= y=20 minor mishap.

As for the engine. When we got it back to= the=20 hangar, the prop would turn only haltingly. You could feel=20 grinding going on inside. First try at turning had it come up h= ard=20 and stop. More fooling with it and it gradually came looser an= d=20 would turn. Really looked like something came loose in=20 there. Pulled a plug from each rotor and did a compression=20 test. Rotor 1 was 80-80-80. Rotor 2 was 2-2-2. Mor= e=20 proof that something had come loose. With that evidence, the=20= insurance company allowed me to remove the engine for inspection.&nb= sp;=20 What I found was a pile of ground up ceramic junk. All the sea= ls=20 were still fine. Lots of time went in to finding where that st= uff=20 came from. Went through every inch of the induction system.&nb= sp;=20 Finally Jason Hutchison (my other on-airport rotary guy) broke the=20= code. While the RV was standing on it's nose, this crap from m= y=20 burned-out Hushpower II ran back up the manifold and in the exhaust=20= port. That is what was grinding. Crap. Now the ent= ire=20 thing is off the firewall including the engine mount. All the=20= wiring is disconnected (did not find anything loose or missing).&nbs= p; I=20 spent the morning looking under the panel for any loose or broken=20= wiring, but found none. When I get the EC-2 out, Jason wants t= o=20 plug it into his plane and we'll do the plugs and injectors test.&nb= sp;=20 If that checks out, Tracy, it is coming to you for a good look. = ; I=20 don't know what else to check. The engine quit just like someb= ody=20 reached over and turned off the ignition. No stumble, no hiccu= p,=20 just instant silence. I honestly do not know if the prop was=20= turning or not. I suspect not, due to the silence and the fact= =20 that one blade is untouched.

As you can see from the photos,=20= there was something going on with Rotor 1. Wear is apparent do= wn=20 stream from the plug holes and all 3 apex seals are starting to chip= in=20 the center. There is quite a lot of carbon also on the rotors=20= after 170 hours.

Going forward, I have decided to look at res= ale=20 value for if/when my RV-12 days arrive. This means putting a=20= (gasp) IO-360 on it. The rotary has given me a safe 10-year ru= n=20 (til now, of course), so I have no regrets, but this is an opportuni= ty=20 to make some changes, and parts are already on the way. I will= =20 still be hanging out at the engine tent at S-n-F and wherever else=20= gatherings happen. Hope to be flying by the first of next=20 year....

I'm sure some of you will have suggestions about wha= t=20 might have gone wrong, and I welcome any kind of speculation, but be= ar=20 in mind I am just looking at a pile of parts and wires at this=20 point. Both fuel pumps were on, tanks were over half full, cra= nk=20 angle sensor worked fine.

Guess it's obvious that I now have a= =20 RD-1A, EC-2, EFI Monitor (Ed's), Felix 68/72 and Props Inc 68/= 72=20 wood props and LOTS of engine parts (my whole 14-year stash)=20 available! And priced to sell!

= Bill=20 Eslick
RV-6 13B/NA EC-2 RD-1A
750=20 Hours

<= /div>