RV-12iS Details

[AndrewR]

I agree on the not understanding why part (and know one has tried to provide an explanation to me).
At one point the discussion in the thread seemed to be leaning towards it defying the laws of physics so it must not be true.
I can assure you it is.

Same power with less fuel is a leaner mixture, and a leaner mixture is hotter - it's as simple as that. This is exactly what the chemistry (and physics) predicts. No laws are defied. No-one should be surprised.

I haven't seen any charts showing leaner mixtures are cooler where the power has been kept constant. They always compare e.g. 100hp LOP with 120hp ROP.
Or they define peak EGT (which is already on the lean side of stoich) as the starting point for their definition of "cooler".

Nice figures though!

[XOverZero]

Originally Posted by AndrewR

Same power with less fuel is a leaner mixture, and a leaner mixture is hotter - it's as simple as that.

Well, foo! There goes my theory about dilithium crystals.

[JwWright57]

....to follow up, when is Rotax coming out with the dilithium engine? And what is the HP? LOL

[rv6ejguy]

Originally Posted by AndrewR

Same power with less fuel is a leaner mixture, and a leaner mixture is hotter - it's as simple as that. This is exactly what the chemistry (and physics) predicts. No laws are defied. No-one should be surprised.

I haven't seen any charts showing leaner mixtures are cooler where the power has been kept constant. They always compare e.g. 100hp LOP with 120hp ROP.
Or they define peak EGT (which is already on the lean side of stoich) as the starting point for their definition of "cooler".

Nice figures though!

Nonsense. I've posted several charts and links from respected sources and your statement flies in the face of what many people flying observe every day with digital engine monitors. Stoich is essentially at peak EGT, give or take about 1%. CHT reduction increases more rapidly than power loss LOP in the 16-17 AFR range where most folks cruise LOP.

Read more on APS and running LOP with turbocharged engines where a bit more MAP is added to regain the lost power. CHTs are substantially lower at the same power/ TAS when running LOP. We can do the same with an atmo engine where we have some more throttle available to add an inch or 2 of MAP.

CHT and FF become the essential factors as described in the latest APS recommendations which I linked to. EGT is just referenced to know that we are LOP.

[Piper J3]

I'm pretty sure Van's was referring to residual heat once the engine is shut off. Electronics on top of the engine are OK when in flight and cool air is moving vertically down through the engine and exiting the cowl flap at the bottom. When sitting on the ground with engine stopped heat travels up through the engine and cooks the electronics. Louvers on top of the cowling allow heat to escape. I leave my oil door open after engine stop for same reason.

[rvbuilder2002]

Originally Posted by Piper J3

I'm pretty sure Van's was referring to residual heat once the engine is shut off. Electronics on top of the engine are OK when in flight and cool air is moving vertically down through the engine and exiting the cowl flap at the bottom. When sitting on the ground with engine stopped heat travels up through the engine and cooks the electronics. Louvers on top of the cowling allow heat to escape. I leave my oil door open after engine stop for same reason.

That was one of the factors that had to be dealt with, but temps with the engine operating were a factor also.

[rvbuilder2002]

Originally Posted by Steenos

When will pricing become available? Is the iS engine going to drastically increase the price?

The base price difference between the ULS and iS engines is $5000.

The price difference between the fuselage kit for each is only $25, but the base price for the new fuselage kit is ~ $500 more than the Gen. 1 fuselage kit.

[rcarsey]

Originally Posted by rvbuilder2002

There will be no option.

The hose used (and shown in the photo) is resistant to effects of fuel exposure but it is not a flex(able) hose.
It can be bent slightly but only enough to allow getting it aligned as installed. It would be impossible to bend it aft to a different filler location.

Hey, just curious what happened with this feature. IIRC, the tube in my iS kit was black.

[Bob Y]

As a point of reference, my Finish kit shipped early Feb. 2019 and it's black too, so also interested to hear the answer. Sounded like a nice feature.

[rvbuilder2002]

The translucent hose was very stiff and difficult to install, and once a bunch of time in service was accumulated the longevity with exposure to auto fuel became suspect so a change was made to the black hose.