REFLECTOR: XL FG Hi Temps/ Siezed Aileron Cable

[Ruben Creus]

Mark,

Do you have a vernatherm on your engine?

I had a similar problem, and after checking everything again and again, I
found out that he Vernatherm valve was not fully closing the bypass. So,
some oil was going to the radiator making it feel hot, and making me believe
that worked, but the fact is that not enough oil was circulating and most
was returning into the engine through the bypass.   

The effect was all my temps went to the roof at climb, as effectively my
only cooling system was air pushed into the engine. Went flying level all
temps looked good as more air was cooling down the engine. So, technically
was like flying with no radiator. 

After replacing the Vernatherm valve, the change was drastically different.
Oil temp went down around 25F, CHT went down also, and now I can climb full
throttle all the way to any altitude with no problem at all and not
suffering about temps any more! All stay cool and nice.

Ruben

-----Original Message-----
From: Mark Magee [mailto:edjonesbrady at gmail.com] 
Sent: Wednesday, November 09, 2011 11:29 AM
To: reflector at tvbf.org
Subject: REFLECTOR: XL FG Hi Temps/ Siezed Aileron Cable

All,
N34XL has some overtemp issues I have been addressing for about 9 months.
With previous mods I had been running acceptable Oil Temps and CHT's, when
flying SOLO/Lower fuel loads. Before the overtemp probs were solved the
summer of 2010 after landing from flying the bird from Livermore CA to
central Texas the ailerons were frozen after shutdown. After diagnosing, the
RH side aileron cable was determined to have siezed, in some way from heat.
I pulled and replaced with a new cable last summer. Scary but looked at as
an anomaly. After a trip this weekend to Wichita Falls TX (166NM trip) the
ailerons are again seized after shutdown after getting home (Thank You
Lord!). On the trip home Oil temps peaked at 257F and CHT's peakedat 445F.
At level off at 12,500 MSL all temps fell back to very normal ranges. I
climbed out at 120KTS getting 500ft/min up at that speed. After calling the
factory John told me to look at vortex generators on the top of the fuselage
for the NACA's for the engine and to climb at 130KTS and 300 ft/min which he
theorized would actually turn into 500 ft/min. I forgot to mention on the
way back from Wichital Falls I was right at max gross weight and we had a
76F ambient temp on the runway at takeoff. Temp at 12,500FT was 53F. After
landing and debarking wife and kids, hangaring the bird and unloading I
tried the stick and have siezed ailerons again. Initial troubleshooting
points to RH Aileron cable again. As well I lost my vacuum pump (in the CLAG
of course). After discussing with my A&P IA hangar mate, he felt that that
the overtemp must be related to the stuck aileron cable and failed vacuum
pump: basically all heat related.
Anyone sized aileron cables on an Xl, or any Velocity. I have now seized
TWO! Fortunately it appears that it is the heat soak after taxi in &
shutdown that does the melting that complete's the seizing of the cable.
Any help appreciated.

Thanks
Mark Magee
Brady TX
N34LX FG 300 HP 75 HRS

Mark B. Magee
Sent from IPhone