REFLECTOR: XL FG Hi Temps/ Siezed Aileron Cable

Wed Nov 9 14:55:35 CST 2011

Scott - Can you post a picture of your lower cowl scoop?  Is it aft facing,
sort of like a cowl flap?

Note that there is a factory NACA vg template on the [LINK:
http://www.velocityxl.com/wiki/index.php?title=NACA_VG_Installation] wiki,
as well a link to [LINK: http://abianconi.hypermart.net/Vortex.htm] CCI
where I bought my VGs.

Brett

	-------Original Message-------
  From: Scott Derrick
  To: Velocity Aircraft Owners and Builders list
  Subject: Re: REFLECTOR: XL FG Hi Temps/ Siezed Aileron Cable
  Sent: 09 Nov '11 13:15

  There are 3 issues here:

  1st and most important is the aileron cables.  You do have fire sleeve
  on the portion of the cables that are in the engine compartment? This
  was a mandatory change/addition back in 2005 or there abouts. Its for
  engine fires but it also insulates the cable from engine heat somewhat.

  2nd and 3rd are your oil and cht temps.

  The first to address is the cht's because high cht's directly effect
  your oil temps.  You need to get those CHT's under control!  445 is
  right at the limit for Continentals. 450 is redline, any sustained temp
  above 400-410 is really too high. Large VG's 6 to 18 inches in front of
  your roof NACA's can help.  A really tight plenum is also needed. I
  ended up adding a cowl scoop to lower the lower cowl pressure, which
  reduced my climb cht's by 20 degrees. get the cht's under control and
  your oil temp problems may go away or at the least be much less in
severity.

  The oil temp is definitely to high.  Above 250F requires an oil change
  as you have cooked some of the ingredients in the oil above their
  rating.  I normally run with one one large oil cooler in the nose. I
  added an adjustable cowl flap to the exit duct that can be opened wider
  for summer departures. that helped a lot. I also have a secondary cooler
  under the rear seat with a couple bilge fans that can provide a small
  amount of additional oil cooling for hot departure climbs and long
  taxis.  I normally never turn it on, but short gas stops where I'm
  departing with a hot engine it helps a bit, maybe 5 degrees.

  You definitely need to get your temps under control. Most important is
  the seized control cable, but your also significantly shortening the
  life of your engine.

  Scott

  -------- Original Message --------
  Subject: REFLECTOR: XL FG Hi Temps/ Siezed Aileron Cable
  From: Mark Magee <[LINK: compose.php?to=edjonesbrady at gmail.com]
edjonesbrady at gmail.com>
  To: [LINK: compose.php?to=reflector at tvbf.org] reflector at tvbf.org <[LINK:
compose.php?to=reflector at tvbf.org] reflector at tvbf.org>
  Date: 11/09/2011 09:28 AM

  > 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
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