Talked with Sam again last night. After getting the
aircraft back to hangar and FAA investigator had done his thing, Sam asked the
investigator whether he wanted him to fire up the engine. The investigator
told Sam that was up to him. So Sam turned on all the switches and the
engine fired right up and ran smoothly - the investigator commented he was
amazed at how smooth the rotary ran. So the engine and it subsystem (at
least initially) appears to function normally.
It appears the nose gear did not fold when Sam encountered
the fence - but apparently the one nose gear rod retaining bolt in the motor
mount may have sheared and permitted the rod and nose gear to fold side
ways. Spinner and prop apparently incurred some damage - which may (or may
not) be minor and fixable. The right wing spar is bent so that wing is
toast, fuselage appears OK and left wing with some trailing edge damage
(probably fixable).
Further discussion with Sam leads me to believe that the
highest probably cause was a "vapor lock" of some type in the fuel line. Sam
stated the engine never stopped running (correction to my earlier report
- where I stated it had quit), but just continued to sputter and failed to
produce power.
The ignition checked out OK as did the rest of the system
back in the hangar. The symptom of sputtering engine and no power would
put a fuel system problem high on my list of suspects and given the high ambient
temps (98F) and the run up before take off -- would leave me to believe
those conditions could have lead to diminished fuel flow.
Sam is going to inspect his coarse filter to ensure it was
not partially obstructed.
One item of note is that Sam does not have any sort of
boost pump between tanks and his EFI pumps. In my early days of testing
while doing power-on stalls (high power low cooling airflow) on a hot day, my
engine started to sputter (unlike Sam I had plenty of altitude when it happened)
and I noticed my fuel pressure fluctuating between 20 - 35 psi. I turned
on my Facet boost pump (puts out approx 6 psi pressure) and it immediately
squelch the problem. So I now take off/land with boost pump on and have
never since had that problem.
We know that any obstruction in a fuel line produces at
least a small pressure drop down stream - Given the suction of the EFI pumps and
even minor restriction of the coarse filter - a lower pressure region would
exist between filter and EFI pumps - elevated temperatures could be enough to
cause some of the fuel in this area to flash into a gaseous state - which
of course is not pumped very well. Its my opinion that a boost pump is a
worthwhile addition in keep pressure in the low pressure part of the fuel system
sufficiently high to prevent the fuel from percolating - particularly on HOT
ambient days. However, make certain that the boost pump is of a type that
does not obstruct fuel flow during a malfuction or when off.
Will provide any further details as Sam provides
them.
As we all know engine failure right after take off is
probably the most difficult and challenging situation you will face.
Unless you immediately lower the nose, your airspeed will bleed off almost
immedately and a stall will occur. So Sam certain is to be commended for
his quick and effective action responding to the event.
Ed
Sent: Tuesday, August 09, 2011 7:49 AM
Subject: [FlyRotary] Re: Sam Hodges Force landing - All
OK
Hmmm, two forced landings in one week … I hope the trend
stops here!
Good job Sam for getting down safely from such a critical
point … 200-300’ on take-off is about as bad as it gets.
Let’s hope we get an answer soon as to the
cause.
Jeff
|
|
|
Sam Hodges just
called me to tell me about his forced landing after take off at Paducha on
7 August. Ed K had notified me the day before of the incident but I
wanted to get more details from Sam before reporting.
Engine sputtered
and quit approx 200-300 ft after take off - Sam stated he had time
to switch from A to B controller - but it made no difference. It was
a hot 97F day. Sam had performed runup before take off and all
appeared OK.
Sam made it to a
dirt road after the engine quit, but the nose gear failed and the aircraft
also incurred some damage to the wing tips. He and his spouse Rose
were shaken up a bit but bascially OK except for sore muscles,
etc.
Sam is meeting
FAA guy to go over the aircraft - back at the hangar- today.
As those of you
who make it to the Paducha flyin last fall know - Sam and Rose have a
beautifuly Renesis installation in an RV-7A - a really nice looking
package.
Sam has been
working out the bugs of his installation - wrestling with temperatures
primarily and this flight was to check out the effectiveness of some of
his recent changes.
I'm sure Sam
will let us know whatever is uncovered pertinent to the
incident.
Just great that
no one was seriously injured or worst
Ed |
Jeff
Whaley
Manager,
Test and Repair
International Datacasting
Corp.
Tele: 613-596-4120 (ext:
2295)
Fax:
613-596-9208
www.datacast.com
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