New Yank

[dewilcox]

New to RF. David Wilcox. Payson Arizona, USA. Just finished conversion of a Jabiru 2200 to Rotec liquid cooled heads, on a Jabiru SP experimental. Have 10 hours on it now. Also flying a Sonex with Jabiru 2200.

 

 

 

[Guest langted]

Just wondering what prompted the conversion? Did you have trouble or just "prudent" with Arizona heat?

 

 

[Downunder]

Interesting set up....radiator looks huge.

 

As your probably aware the rotax's have water cooled heads also, but their radiator looks tiny compared to yours.

 

Do you have a thermostat?

 

 

[danny_galaga]

I would say the radiator is larger to compensate for the position. Very tidy set up :)

 

 

[dewilcox]

The core element of my radiator is 99 in^2.  One example of the Rotax 912 radiator is 70 in^2.  I looked at smaller radiators and alternate nacelle locations.  But since the space was available behind the engine, why not go with a robust size?  There are two electric water pumps, one on the airframe system, the second backup pump is on a rechargeable lithium ion battery.

 

Water temp in cruise at 7500’ with 85df oat is now about 200df.  My primary problem was the oil temperature which was up to about 235 in climb, 220 in cruise.  It is now a comfortable 195 in cruise after relocating the oil cooler and baffling the engine sump fins.  Water temp is about 230 in prolonged wot climb.  CHT is about 310 in climb.  When I get more time on a stable configuration I’ll finish an article I am writing about the conversion.  All of my cooling air inlets are currently crude sheet metal.  I’m now finished with the mechanical installation and ready to begin extensive fiberglass work.

 

I bought the plane with a heat damaged engine.  All but one of the heads were cracked.  It also had a minor accident in the past.  A wheel had come off, destroyed the landing gear and had a prop strike.  They repaired the gear with with a Grove solid aluminum design, huge wheels and brakes.  That system prevented installation of all fairings.  I have the correct gear (30 lbs lighter) on it now and am in the process of repairing and installing wing root fairings and wheel pants.   The pervious bunch installed a Warp Drive prop.  Which is also coming off as soon as the fairing work is done.  The cruise IAS is only about 90 mph now.  I’m confident the POH performance will return when I get it back to OEM configuration.  I was told by JabiruNA that new air cooled heads were not available due to the Camit fiasco.  That is the main reason that I decided on the Rotec liquid cooled heads.  Rotec customer support is good.

 

The plane does not feel as solid as my Sonex in flight, very sluggish.  It is also about 25kts slower, which I’m sure is part of the “feel” problem.  I’m confident that 10kts will come back with the right prop and fairings, possibly 15.  If I do get 15, I’ll be selling the Sonex.  If not, I’ll sell the SP.  I currently have 15 flight hours on the Rotec-Jabiru.  The Rotec heads seem to be a good product.  The CHT is higher than I expected, but beats the heck out of the air cooled heads.  I need to recheck the solid lifter valve clearance soon.