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Rotax E-Learning video on detonation and pre-ignition
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Roger Lee

Joined: 10 Jan 2006
Posts: 1464
Location: Tucson, Az.

Posted: Fri Dec 10, 2010 3:10 pm Post subject: Rotax E-Learning video on detonation and pre-ignition

FYI



Rotax E-Learning video on detonation and pre-ignition.



Watch it.



http://rotax-owner.com/index.php?option=com_content&view=article&id=201:detonation&catid=15:training&Itemid=174

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Tucson, Az.
Rotax Instructor & Rotax IRC
Light Sport Repairman
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Cell 520-349-7056

rparigoris

Joined: 24 Nov 2009
Posts: 805

Posted: Fri Dec 10, 2010 3:52 pm Post subject: Re: Rotax E-Learning video on detonation and pre-ignition

Hi Roger



Thx. for posting link to video on Detonation and Pre-ignition.



They mention in the video use of a Carbon Monoxide tester to determine you are running rich enough (the more Carbon Monoxide present the richer you are running). I know Rotax wants you to measure the Carbon monoxide on each cylinder of a 914 when you are creating "War Emergency Power" (above 108% power).



Have you ever measured Carbon monoxide? Can you go into details of how you plumbed to measure and what monitor you used.



If you don't have any experience measuring Carbon Monoxide, can you point me to someone who has?



I purchased one of these and am getting closer to using it:

http://www.europaowners.org/forums/gallery2.php?g2_itemId=78722

BTW I have modified my intake system (intercooler).



Thx.

Ron Parigoris

Roger Lee

Joined: 10 Jan 2006
Posts: 1464
Location: Tucson, Az.

Posted: Fri Dec 10, 2010 4:39 pm Post subject: Re: Rotax E-Learning video on detonation and pre-ignition

Hi Ron,



I confess I do not really have any experience with the carbon monoxide tester. It usually isn't needed for a 912, but certainly could be helpful with the 914. There just isn't many 914's around. little by little they are growing, but at $31K not very fast. The second hand military ones aren't even supposed to get on the market, but a few individuals have managed to get their hands on a few and then they make the claim about an overhaul, but it is superficial at best. A real overhaul on a 914 would cost a pretty penny. I don't know of a sole using the CO tester.



Sorry

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Roger Lee
Tucson, Az.
Rotax Instructor & Rotax IRC
Light Sport Repairman
Home 520-574-1080 TRY HOME FIRST
Cell 520-349-7056

rparigoris

Joined: 24 Nov 2009
Posts: 805

Posted: Fri Dec 10, 2010 8:11 pm Post subject: Re: Rotax E-Learning video on detonation and pre-ignition

Hi Roger



Thx. for the reply.



I purchased one from Bing (same one Eastwood sells). My idea is to test one cylinder at a time by running the sample tube inside the cockpit (through one of my Ultimate ventilators) to the tester which will be inside the cockpit. I will have a valve on it where it will be filling cockpit with carbon monoxide for only a very short time (of course ground testing only).

I don't like lean too much when making serious horsepower. As a matter of fact I am going to taint my mixtures above 65% a slight bit on the rich side as confirmed by this Carbon Monoxide tester and my Split Second O2 sender and display. I am incorporating the ability to lean by allowing the tube going from the airbox which is at airbox pressure to the carb float bowls to leak via a needle valve to the balance tube. The "hand in the breeze" higher pressure portion of the airbox that feeds the rich side of the enrichment solenoid will not be effected at all. As a matter of fact I am incorporating an emergency "rich" switch that will allow me to energize the enrichment solenoid anytime I like. There will be a LED that will show when the solenoid is energized, which is also nice to know when the TCU is supposed to be doing the energizing over 108% power. If for any reason my circuit failed for some reason, things are running lean for some reason or things are starting to run hot, I will energize the enrichment solenoid. I am installing a diode to protect the TCU from back feeding from my overriding power just in case there is something in the TCU that wouldn't like too much to be back fed.

Anyway plan is to use two UMA EGTs, a UMA fuel flow gauge (two Flowscan 201Bs and a Matronics box to subtract return flow) and Split Second O2 gauge to help me finda proper proper mixture from slight rich at 75% or less. I will have ability to run slight rich if things are a bit hot. Over 75% power I will err a bit rich side and over 100% or 115% near max. rich of what Rotax has to say.

Ron Parigoris

m.tucciarone(at)hotmail.c
Guest

Posted: Sat Dec 11, 2010 4:53 am Post subject: Rotax E-Learning video on detonation and pre-ignition

?Thanks for sending the link.



I have had the conversation with a friend, that flies an Air Cam, about 

continuous cruse RPM. He has his engines (912s) at 4500. This video says to 

keep it above 5200. I cruse at 5300-5500.





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Roger Lee

Joined: 10 Jan 2006
Posts: 1464
Location: Tucson, Az.

Posted: Sat Dec 11, 2010 6:38 am Post subject: Re: Rotax E-Learning video on detonation and pre-ignition

912's



If you only have a ground adjustable prop then we try to balance the climb/cruise setup up and make the engine happy at the same time. The best WOT flat & level rpm is 5500 WOT. This gives you good climb, good cruise speed and the best fuel economy for an individual rpm setting. Balance is the key. This is a good place to be too if you have to fly your plane at WOT because of an emergency like a broken carb cable on one side then you can do that without any problem at 5500 WOT. If you have it set over 5550 then you would be limited to a 5 min. run time. 5500 is Rotax's continuous run rpm. A good cruise rpm (with the max WOT rpm at 5500) is 5000-5300 depending on the plane and application. I prefer and Rotax too, 5100-5300 for cruise. If you run on only 100LL then cruise at 5300 to help keep the lead blown out. At a 5500 WOT rpm then your take off rpms will be up to 5000 or more. This take off rpm will depend now on what flap setting and what climb angle you chose that will either load or help unload the prop. Your planes over all configuration will play a part in this, too. Never set your engine up to only run (i.e. 5000-5200) WOT rpm. It loads the engine too much and over time it will cause problems that you won't see until it's too late. These low rpm settings really overload an engine at take off with rpms below 5000. Having an engine setup to run 5300 or less rpm WOT throttle is counter productive. You get worse climb, worse cruise and worse fuel economy. I have proven this to hundreds of people so there really isn't a valid argument to set your WOT to low cruise rpms. If you have a special need for a better climb prop, like living and flying at very high airports, altitudes or maybe a float fly, ect... then you may need a higher rpm setting to accommodated the special circumstances, plus you will get better performance while flying at the high altitudes with a little flatter pitch. Everyones pitch on the prop setting will be different because we all live and fly at different altitudes, have different props and different fuselage aircraft. I will say that if you truly want to see 5200 on take off as Rotax wants then your WOT flat and level is closer most likely 5700 or more. For me personally this isn't a good balance.

having the prop to get 5500 rpm WOT has another big plus. If you screw up a landing and need that full throttle save then the prop/engine rpm spin up is quick and more likely to save your tail. If the rpm was set too low then rpm spin up is slow and it will result in poor save my tail time.



All bets are off for the lucky few that have an in flight adjustable prop. They can get the best of all worlds. But even with these guys if they have set the prop to only turn 5100-5200 WOT during cruise then it's counter productive and over loads the engine. Just because they have an in flight adjustable prop doesn't always mean they use it properly.

Cruising in the 4000 rpm range for extended periods is not good for your engine. It is ok for a short look at something and landing setups, but not for a constant use. Your engine was specifically designed to run all it's life in the 5000's. It was never intended to run in the 4000's and is really hard on the engine over time and has much more vibration. Just because you can't feel the stress and vibration doesn't mean it isn't there.



Be nice to your engine it cost $20K and it is one of the only things keeping you in the air and safe.

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Tucson, Az.
Rotax Instructor & Rotax IRC
Light Sport Repairman
Home 520-574-1080 TRY HOME FIRST
Cell 520-349-7056

Float Flyr

Joined: 19 Jul 2006
Posts: 2704
Location: Campbellton, Newfoundland

Posted: Sat Dec 11, 2010 8:06 am Post subject: Rotax E-Learning video on detonation and pre-ignition

What is the best WOT with the tail tied down?  Around what pitch angle is a

good place to start?  (80 hp 912 UL)



Noel



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Noel Loveys
Kitfox III-A
Aerocet 1100 Floats

m.tucciarone(at)hotmail.c
Guest

Posted: Sat Dec 11, 2010 9:28 am Post subject: Rotax E-Learning video on detonation and pre-ignition

?The video says stay above 5200. You say 5100 to 5300. Who is correct?



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Roger Lee

Joined: 10 Jan 2006
Posts: 1464
Location: Tucson, Az.

Posted: Sat Dec 11, 2010 4:55 pm Post subject: Re: Rotax E-Learning video on detonation and pre-ignition

Actually both are correct. Rotax publishes numbers like that, but there are way to many applications in the world  for everyone to be spot on, so why try to be at least close. Then the teachings in school aren't right along with the book either. So we try to balance a little. Plus we all have different setups. If you are at least 5000+ on take off and at 5500+ WOT you can sleep well at night.



Hi Noel,



Setting the rpm on the ground static is just to get close. Pitch angle does no good unless you are talking about two identical planes and props. The only way to really tell after that course static adjustment is to get into the air and get some real flight numbers. Shoot for around 5200 static on the ground and that will get you close enough for a flight test to dial it in where it really needs to be.

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Roger Lee
Tucson, Az.
Rotax Instructor & Rotax IRC
Light Sport Repairman
Home 520-574-1080 TRY HOME FIRST
Cell 520-349-7056

Float Flyr

Joined: 19 Jul 2006
Posts: 2704
Location: Campbellton, Newfoundland

Posted: Sat Dec 11, 2010 8:27 pm Post subject: Rotax E-Learning video on detonation and pre-ignition

What would you recommend to be a preliminary AOA for the prop?  Warp, nickel

edge, square tip, 72" on a Kitfox II?



Noel



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Noel Loveys
Kitfox III-A
Aerocet 1100 Floats

Roger Lee

Joined: 10 Jan 2006
Posts: 1464
Location: Tucson, Az.

Posted: Sat Dec 11, 2010 8:53 pm Post subject: Re: Rotax E-Learning video on detonation and pre-ignition

Hi Noel,



If you are flying with floats you may want a little flatter pitch for a little better climb off the water with more weight. I have no recommendation for the pitch, but only to set the static at 5200-5300 and go out and give it a try.

I know you have been flying your plane, so what is your WOT setting right now and how does it perform? 

Just a side note*

That particular prop from Warp isn't recommended by Rotax because of it's inertia weight.

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Roger Lee
Tucson, Az.
Rotax Instructor & Rotax IRC
Light Sport Repairman
Home 520-574-1080 TRY HOME FIRST
Cell 520-349-7056

rickofudall

Joined: 19 Sep 2009
Posts: 1392
Location: Udall, KS, USA

Posted: Sun Dec 12, 2010 4:17 am Post subject: Rotax E-Learning video on detonation and pre-ignition

You don't say if it is a two or three blade propeller, but for a start with either, try 10 degrees measured at the prop tip. That works out to about 38.5" pitch.



Rick Girard



 On Sat, Dec 11, 2010 at 10:23 PM, Noel Loveys <noelloveys(at)yahoo.ca (noelloveys(at)yahoo.ca)> wrote:

[quote] --> RotaxEngines-List message posted by: "Noel Loveys" <noelloveys(at)yahoo.ca (noelloveys(at)yahoo.ca)>

 

 What would you recommend to be a preliminary AOA for the prop?  Warp, nickel

 edge, square tip, 72" on a Kitfox II?

 

 Noel

 

 --

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Dick Maddux

Joined: 24 Jun 2008
Posts: 516
Location: Milton, Fl

Posted: Sun Dec 12, 2010 5:15 am Post subject: Rotax E-Learning video on detonation and pre-ignition

>What is the best WOT with the tail tied down?  Around what pitch angle is a

      good place to start?  (80 hp 912 UL)

      

      Noel<

  

 Noel I have my Kiev prop set at 71/2 degrees on my 80hp Kitfox. This gives me 5200 rpm(per the Rotax service bulletin) (at) WOT at the start of the take off roll. This prop angle would probably do you no good as you most likely have a different prop. I had to set the angle about 3 times until I got the 5200 I was looking for.

                                            Dick Maddux

                                            912UL

                                            Milton,Fl



 [quote][b]

Dick Maddux

Joined: 24 Jun 2008
Posts: 516
Location: Milton, Fl

Posted: Sun Dec 12, 2010 5:36 am Post subject: Rotax E-Learning video on detonation and pre-ignition

>  What would you recommend to be a preliminary AOA for the prop?  Warp, nickel

      edge, square tip, 72" on a Kitfox II?

      

      Noel<

  

 Noel,

  I too had the 72" Warp nickel edge prop (although mine was the tapered tip). I removed it and installed the lighter Kiev. That solved my engine run on problems I was sometimes having at shutdown (prop would turn backwards about three revolutions) I suspect the mass of the Warp was causing the prop to flip back at the top of the "dog gears" in the gearbox at shutdown. For whatever reason I now have a much smoother , quieter  propeller and NO kickback. But then, I am the only one in the country that has had the kickback problem.

                                          Dick Maddux

                                          912UL

Kiev_prop.jpg

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Float Flyr

Joined: 19 Jul 2006
Posts: 2704
Location: Campbellton, Newfoundland

Posted: Sun Dec 12, 2010 5:54 am Post subject: Rotax E-Learning video on detonation and pre-ignition

The last time I flew the plane it was with a 582 UL with a three blade IVO

IFA.  I think the 914 and the two blade WARP may be a whole new quintal of

fish!



Noel



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_________________
Noel Loveys
Kitfox III-A
Aerocet 1100 Floats

Float Flyr

Joined: 19 Jul 2006
Posts: 2704
Location: Campbellton, Newfoundland

Posted: Sun Dec 12, 2010 6:01 am Post subject: Rotax E-Learning video on detonation and pre-ignition

Thanks Rick that’s where I’ll start.

 

Noel

 

From: owner-rotaxengines-list-server(at)matronics.com [mailto:owner-rotaxengines-list-server(at)matronics.com] On Behalf Of Richard Girard

Sent: December 12, 2010 8:44 AM

To: rotaxengines-list(at)matronics.com

Subject: Re: Re: Rotax E-Learning video on detonation and pre-ignition



 

You don't say if it is a two or three blade propeller, but for a start with either, try 10 degrees measured at the prop tip. That works out to about 38.5" pitch.

 



Rick Girard

On Sat, Dec 11, 2010 at 10:23 PM, Noel Loveys <noelloveys(at)yahoo.ca (noelloveys(at)yahoo.ca)> wrote:

--> RotaxEngines-List message posted by: "Noel Loveys" <noelloveys(at)yahoo.ca (noelloveys(at)yahoo.ca)>



What would you recommend to be a preliminary AOA for the prop?  Warp, nickel

edge, square tip, 72" on a Kitfox II?



Noel



--

_________________
Noel Loveys
Kitfox III-A
Aerocet 1100 Floats

Float Flyr

Joined: 19 Jul 2006
Posts: 2704
Location: Campbellton, Newfoundland

Posted: Sun Dec 12, 2010 6:05 am Post subject: Rotax E-Learning video on detonation and pre-ignition

Thanks Dick:

 

I wanted to initially set the pitch close to the 5300 as possible so I wouldn’t be all over the field trying to zero in...  BTW the 5300 instead of 5200 is for two reasons...  1 STOL performance in the Kitfox and 2. The plane is hardly blistering fast in fact it is close to flying a barn door broadside to the wind.  A great plane for this area.

 

Noel

 

From: owner-rotaxengines-list-server(at)matronics.com [mailto:owner-rotaxengines-list-server(at)matronics.com] On Behalf Of Catz631(at)aol.com

Sent: December 12, 2010 9:43 AM

To: rotaxengines-list(at)matronics.com

Subject: Re: Re: Rotax E-Learning video on detonation and pre-ignition

 

 	  Quote: 	
		  What is the best WOT with the tail tied down?  Around what pitch angle is a

      good place to start?  (80 hp 912 UL)
	


      

      Noel<



 



Noel I have my Kiev prop set at 71/2 degrees on my 80hp Kitfox. This gives me 5200 rpm(per the Rotax service bulletin) (at) WOT at the start of the take off roll. This prop angle would probably do you no good as you most likely have a different prop. I had to set the angle about 3 times until I got the 5200 I was looking for.



                                           Dick Maddux



                                           912UL



                                           Milton,Fl

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  [quote][b]

_________________
Noel Loveys
Kitfox III-A
Aerocet 1100 Floats

daveaustin2(at)primus.ca
Guest

Posted: Sun Dec 12, 2010 7:24 am Post subject: Rotax E-Learning video on detonation and pre-ignition

I'd be a bit concerned that with prop set to 5300 static that it could easily over-rev on climbout. 

I use 5000 static.

Dave

dave

Joined: 22 Sep 2006
Posts: 1382

Posted: Sun Dec 12, 2010 7:34 am Post subject: Rotax E-Learning video on detonation and pre-ignition

5100 to 5300  work well for me .

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JohnF

Joined: 13 May 2010
Posts: 124

Posted: Sun Dec 12, 2010 9:36 am Post subject: Rotax E-Learning video on detonation and pre-ignition

Thanks for that great information, Roger. I made it a point to fly this 

morning (wind finally stopped) and got 5,540-rpm WOT in straight and level 

flight at our pattern altitude of 8300-ft. I am going to leave things right 

there. Thanks again for the information, Roger



JohnF

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