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REFLECTOR: Vac Pump, Alternator, Exhaust,& Brakes



Operational Notes on N19DW, XL/RG, first flight Aug 8,1998

(1) Vacuum Pump and System - USE ONLY SILICONE SPRAY ON ALL THREADS AND
CONNECTIONS, DO NOT USE TEFLON TAPE OR ANY OTHER KIND OF SEALER. We used
teflon tape on pump threads and apparently teflon particles got inside pump
and ruined blades due to their close tolerance fit. Result- $200 to replace
pump. 
(2) Alternator - if you are considering using an automotive unit be aware
that those alternators turn the opposite direction on a Lycoming engine
(unless you have a "L"engine which is opposite turning). I burned up diodes
on two 60 amp auto aternators due to fan turning wrong direction and extra
heat from down draft (plenum) cooling on engine. I now have a B & C
alternator which so far is fine. B & C claims they have never had a failure
due to heat, however I do plan to add a small NACA scoop on bottom of
cowling to shoot some cool air to alternator.
(3) Exhaust Pipe - cracked open all the way thru horizontal pipe and half
way thru vertical pipe at joint below pilot side cylinder closest to
firewall after only 12 hours. Fortunately break  occured on ground and
discovered before flight. Original S.S.pipes, purchased from Velocity, were
modifed by cutting and moving exit pipe about 15degrees more aft plus
adding doublers in weld area. Also we had a rather heavy oil breather exit
pipe clamped to that exhaust pipe so extra weight could have caused break
or perhaps pipe was hitting cowling cutout due to engine vibration during
startup. RECOMMEND: (A) BEFORE EVERY FLIGHT , GRAB EACH EXHAUST PIPE AND
CHECK FOR SECURITY. (B) MAKE SURE SAFETY CABLES ARE ATTACHED NEAR END OF
EACH EXHAUST PIPE. 
(4) Brakes - after a few hours were very mushy and pedals hit canard
bulkhead before brakes were solid. Cause - too short of a stroke for brake
cylinder. The linkage between brake pedal and brake cylinder was lengthened
considerably so braking begins much sooner as pedal is pushed. Also rudder
cables adjusted much shorter so rudders begin outward movement as soon as
pedal is moved. Bottom aft corner of rudders move outboard almost 5 inches
before braking begins. 

VENDORS I HIGHLY RECOMMEND:
Don George. Inc , Orlando FL - for engines and overhauls - 1-800-222-6690
Eastern Avionics, Punta Gorda, FL - avionics plus prewired packages
                                                                  
1-800-628-2667
ElectroAir(Jeff Rose)-Chattanooga, TN- solid state ignition- 
Navaid Devices- Chattanooga TN - autopilots -(423) 267-3311
Vision Microsystems- Bellingham WA- engine monitoring systems-
                                                                   (360)
714-8203

I can try to answer any questions you might have at my E-Mail address
donaldwhite@compuserve.com         or  phone   (716) 649-6137
Don White