Polishing intake manifolds

by Eugene Klimenko in General Tech Discussion 6 years ago

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Re: Polishing intake manifolds

by Eugene Klimenko » 6 years ago

Eugene Klimenko

12 74 1

Very good summary about how we all feel!!!

We should print this letter and send it to them.

I was living in Germany before I came to this country. So, I will be looking for guys with German accent under Rotax tent. Maybe I get lucky and get to talk to real engineer this time.

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Re: Polishing intake manifolds

by Roger Lee » 6 years ago

Roger Lee

127 5.21k 4.79k

Simple answer. It cost millions.it isn’t just a simple add on.

Roger Lee
LSRM-A & Rotax Instructor & Rotax IRC
Tucson, AZ Ryan Airfield (KRYN)
520-349-7056 Cell

Thank you said by: Eugene Klimenko

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Re: Polishing intake manifolds

by Eugene Klimenko » 6 years ago

Eugene Klimenko

12 74 1

Something else that I think very interesting.
I did talk to guy in Norway, who makes injection conversion kits for 912 engines.
Their best performing arrangement is what they call 4-in-1. Where one throttle body is feeding 4 cylinders with a specially designed manifold with equal length to every cylinder.($6000)

They also do make kit with 2 throttle bodys to go as Direct carburetor replacement. When I asked him about that system. He said that this type of arrangement doesn't work very good at all. And it's only used in Situation where space is very limited under engine cowling.

Now that we are talking about this, I am making conclusion that manifold 4 into 1 where one unit is feeding 4 cylinders apparently working better for carburetion or injection as well.

http://webshop.edgeperformance.no/index.php?id_product=440&controller=product

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Re: Polishing intake manifolds

by Bill Hertzel » 6 years ago

Bill Hertzel

13 1.95k 7.97k

A relatively easy conversion would be to mount the 912is airbox on a ULS and mount a single carburetor in place of the throttle body.

Unlike the optional USL airbox that is Before the Carbs, the 912is airbox is After the throttle body.

The 912is Airbox has way more design built into it than meets the eye.
The intake manifolds do not stop where they attach to the Airbox.
There is another foot of intake pipe internal to the airbox that extends to the opposite side of the airbox.
The Right cylinders actually get their air from the left side of the airbox, and the Left cylinders get air from the right side.
It is not just a chamber with fittings attached where it was convenient.
It has the look and feel of a tuned intake manifold.
This simple looking airbox was not designed in a week!

Bill Hertzel
Rotax 912is
North Ridgeville, OH, USA
Clicking the "Thank You" is Always Appreciated by Everyone.

Thank you said by: Eugene Klimenko

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Re: Polishing intake manifolds

by Eugene Klimenko » 6 years ago

Eugene Klimenko

12 74 1

From Rainbow Aviation -
"The Rotax 912 is essentially two engines connected to a single crankshaft and gearbox with both the left and right sides of the engine having their own independent carburetor, ignition, and exhaust system Figure: 1. As you might well imagine, having two engines trying to run a single propeller requires a bit of choreography between the right and left side of the engine in order to make things run smoothly. Most of us, who have spent a considerable amount of time in the air, can remember a time when one of the cylinders on a four-cylinder engine just quit firing, maybe from fouled spark plugs, or a plugged fuel injector. Regardless of the source, if you have ever lost a cylinder, it likely got your attention. Now imagine losing two cylinders. This is nothing short of an all-out assault on your engine and airframe. The shaking can be so violent that the fear of the motor departing the airframe becomes a realistic concern. With an engine like the Rotax 912, which has the right and left side induction systems isolated from each other, you can see the potential hazard with having one throttle wide open and the other at idle. The resulting reaction of the engine would be similar to the scenario of losing two cylinders in our previous example. In fact, we now train pilots differently in a Rotax powered aircraft by teaching them to advance the throttle to full throttle in the event of a violently shaking engine. The reason for this is that on most Rotax powered aircraft the throttles are spring-loaded to the full throttle position. As a result, in the unlikely event of a throttle cable failure, pulling the one remaining throttle cable back to idle when the engine starts to shake just exacerbates the problem. By advancing the throttle to full throttle, it allows the throttle springs to bring both carburetors to the (same) full throttle position. This allows the engine to run smoothly and the aircraft to be flown to the nearest airport where the engine can be shut off for a dead stick landing, a better scenario than losing the engine power entirely. Theoretically, at full throttle the carburetors are perfectly synchronized by the throttle arms hitting the full throttle stops simultaneously."

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Polishing intake manifolds

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