In Heavy Maintenance class with Eric Tucker as instructor

[Anticept]

Addressing two more questions.

 

The variable venturi's effect on acting like a blockage is insignificant, and the engine ratings are calibrated using said VV carbs. Yes, more power could be achieved with a traditional mixture control, but the amount of change is extremely small, as there is very little effect on the airstream with the venturi vs the throttle plate. You can actually make the carb work with a vacuum cleaner! The most important thing is to keep the carb clean to keep it running efficiently!!!

 

As for improvements to the engine: The Carbeurated engines are done. Rotax is only going to make changes for safety and problems as necessary to keep the engine safe, but reengineering isn't going to happen. Rotax is committing 99% of their resources now to the iS engine.

 

That's it, the class is over. If you had any more questions, it's too late to ask them.

[Anticept]

One last thing:

 

The carbeurator begins to run a little rich around 6-7,000 feet. Above that, it can't compensate as easily, but it's not going to make the engine stop or anything. That's why changing the circlip position on the ULS to run a little leaner can work for people at altitude to make up for the deficiency, but anyone with a ULS engine with the modification cannot run at lower altitudes as the engine will start to run rough.

[Anticept]

Hi Corey -- could you ask Eric about the Advance Ignition Module shortage in the US?  The 3 US retailers have been out of stock since mid-July and are still potentially 4-6 weeks away from meaningful restocking.  CPS might be receiving some this week (with me being #1 on the list).  I'm aware of approximately ~10 owners of 06/07 models grounded due to lack of parts.

Didn't see this question. Parts availability is not part of Eric's line of work.

 

That said, just so everyone knows, the ignition modules are produced in house. The ducatti name on the ignition boxes don't mean anything, and if you called Ducatti, they would tell you the part doesn't exist. It is purely a rotax build stuffed inside of those boxes. Newer produced boxes don't have the Ducatti name.

 

The voltage regulator IS ducatti, though

[Anticept]

Roger, some companies are more open than others and I as a consumer make choices. The attitude of Rotax as Corey is passing along is not consumer friendly.One of the dangers of the "secret society" is that the "secret society" can make up anything it wants and the rest of us are stuck with whatever the priesthood preaches. I simply won't live like that.OK, off my soap box, but I'll not change my attitude toward wanting to see documented references for whatever is cited as the way we should be maintaining or operating the engine. We have seen an example in VAF of where Dean Vogel and you may have differing interpretations about some Rotax issues. That is the very disagreement that is unsettling to the consumer.

I don't like it either, but you are going to find it everywhere in aviation. Say too much and a lawyer will use your own words and bury their thumb in the wound, and even give it a few twists.

 

Rotax is undergoing a lawsuit a year on this side of the planet, something that Eric is directly involved with as RFSC and the distributors tend to be a target lf the suits. Whether or not those cases are right or wrong, it doesn't matter, history has shown that jurys are the worst enemy of aviation companies because they are awarding unnecessarily high punitive damages that are running more and more aviation companies out of business. If the manufacturer does something wrong that gets you hurt, you do have a right to compensation, but not as much as they have been awarding in aviation lawsuits.

 

Rotax has switched parts more than a few times because of those lawsuits and growing concern with liability too. The original old old style fuel pumps, pierburg, (these are before the pumps that have the replacement bulletin on them), and the VDO style sensors, were bought out by Siemens. Siemens has stated NO AIRCRAFT PARTS. They refuse to be involved in the legal landscape and expose themselves to that level of liability.

 

Seriously, if you want more consumer friendlyness in aviation, then tort reform needs to happen to tone down the liability exposure. Insurance is ungodly expensive for manufacturers, and even for myself, I would have to pay a minimum of 10,000 dollars per year to work on public aircraft.

[Ed Cesnalis]

CT, interesting question.  I too am very interested in knowing the actual position of the slide (valve?) in the carb.  Given the CV design, I don't see any way to actually observe or determine it, however. 

 

Jeremy did my condition inspection today and pointed out how easy it would be to observe.  All you have to do is remove the air intake hose and put a light and a go-pro in its place.  Start with my hangar where DA was 9,000' today and photo the needle at various throttle settings including WOT.  Next we would fly to Tracy and do the same thing at sea level.

[Anticept]

Jeremy did my condition inspection today and pointed out how easy it would be to observe.  All you have to do is remove the air intake hose and put a light and a go-pro in its place.  Start with my hangar where DA was 9,000' today and photo the needle at various throttle settings including WOT.  Next we would fly to Tracy and do the same thing at sea level.

Use a borescope

[Jim Meade]

Corey,

 

Thanks very much for your very interesting and useful commentary.

 

Jim

[Anticept]

Corey,Thanks very much for your very interesting and useful commentary.Jim

Thanks for hearing me out