REFLECTOR: N4PE flies but not so good at the end

Scott Derrick scott at tnstaafl.net
Mon Mar 30 20:08:26 CDT 2009


Yeah,it  sure sounds like it could have been fuel starvation.

Were the engine parameters recorded?  Can you check what the fuel flow was?

Scott

Chuck Jensen wrote:
> Brian,
>
> I can guess with the best of them, even if my guesses aren't very good.  One clue is the low sump level.  Any chance that the sump and/or fuel system wasn't venting properly and it was either creating a vacuum or otherwise not allowing fuel to flow to the sump and/or engine.
>
> I've saw more than a couple motorboats setting dead in the water.  They said they'd switched to a fresh portable fuel for the outboard and it ran for a few minutes, then lost power.  After waiting a while, the motor would start, but then slowly die.
>
> After suggesting they open the vent on the portable fuel tank...the outboard ran a lot better.  It's a long shot, but another thing to check out.
>
> Chuck Jensen
>
>
> -----Original Message-----
> From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org]On
> Behalf Of Brian Michalk
> Sent: Monday, March 30, 2009 5:09 PM
> To: Velocity Aircraft Owners and Builders list
> Subject: Re: REFLECTOR: N4PE flies but not so good at the end
>
>
> Dennis,
>
> Thanks.  I went out to the airport with the FAA inspector to determine 
> if it's an accident or incident today.
>
> I think electronic is the way to go, it's just more difficult to set 
> up.  I'll pull off the tables, and certainly go over them.  Now I've got 
> to get over this feeling of depression and get back to work.
>
> Dennis Martin wrote:
>   
>> I went to Cincinnati and left my laptop behind. What a shock to see 
>> this email. Your preflight preparations are impressive and remind all 
>> of us how critical it is to cover all the bases. I'm close to 12 years 
>> on my project and can't imagine how disappointed you feel, but I'm so 
>> glad that you're in one piece.
>>
>> I've also got electronic ignition/fuel injection. I'll do all I can to 
>> make it perfect before rotating, but there's no guarantee that ground 
>> testing is the same as flying. All the best in your Phoenix project.
>>
>> Dennis
>>
>> 2009/3/29 Brian Michalk <michalk at awpi.com <mailto:michalk at awpi.com>>
>>
>>     Group,
>>
>>     Today was my first day to fly.  Unfortunately it resulted in an off
>>     airfield landing.  It's been a long day, and I wanted to get this out
>>     there before the FAA notice was posted.
>>
>>     I have several theories at this point as to what happened, and I'll go
>>     through each one trying to identify the smoking gun.
>>
>>     First, the flight.  Approximately 12:30 pm with a 5 knot southern
>>     wind,
>>     I prepared for takeoff.  Some people think I am a bit cautious, and
>>     maybe so in many cases, but today was a good day to be cautious.
>>      I had
>>     the local fire department notified, and they were standing by.  Pretty
>>     nice folks, and I think they liked having something interesting to do.
>>     Dean Norris with a sharp eyed passenger took off in his Velocity
>>     to fly
>>     chase.  I had maps made, and distributed to everyone with big
>>     letters to
>>     help direct ground crews in a bad event.  Dean took off, and I waited
>>     for him to get on downwind before starting my roll.  Previous to
>>     today,
>>     I had been doing a bit of fast taxiing, and nothing abnormal ever
>>     showed
>>     up.  I rotated several times during fast taxi tests at about 65mph.
>>     Today, as I accelerated through 70, I remember thinking how odd it was
>>     that I had not yet rotated, but this was the first time under power.
>>     Rotation speed is lower without the power vector pushing the nose
>>     down.
>>
>>     I accelerated, and lifted off about 75kts.  The plan was to climb to
>>     1000'AGL at 90kts.  I reached my 90kts very quickly, and kept pulling
>>     nose up a little bit more.  Man, there was a lot of power.  The plane
>>     flew straight.  No major stick forces that I can recall.  I reached
>>     about 900 feet, and the engine began losing power.  I immediately
>>     turned
>>     crosswind to downwind.  I wish I could say I was maintaining optimal
>>     airspeed, but I don't recall any airspeeds after that point, and
>>     looking
>>     back would have been the absolute best thing to maintain.  I
>>     pulled out
>>     some throttle, and regained some engine power, but not enough to
>>     arrest
>>     the descent.  I was still on downwind, and picked out a field north of
>>     the field to put down in.  Then I changed my mind.  With the bit of
>>     power I had, I decided to turn south into the find to reduce my ground
>>     speed.  I picked out a field, and turned to it.  I ended up about 600
>>     yards north from the end of the runway facing south.
>>
>>     I will remember this day forever, and will play back the choices into
>>     eternity.
>>
>>     The plane contacted ground, and came to a stop within 47 yards.  I
>>     stepped it off.  The ground was quite soft.  The gear all had been
>>     sheared off.  The right tip of the canard dug into the ground, and
>>     when
>>     it did, caused compression crumpling on the right side of the
>>     fuselage.
>>      Next, the plane wanted to move left, and that's when the main gear
>>     really dug in and sheared off, which was quite a jolt.
>>
>>     Nothing broken for me except my ego.  I literally have a minor scratch
>>     on my left hand, that's all.  Amazing.  I'm not even sore ... yet.
>>
>>     Going back to the causes, I have a few theories that need to be
>>     researched.  As I taxied over to the fuel pumps, I saw the low fuel
>>     light was on.  After taking on five gallons each side, I noticed the
>>     warning light had turned off.  When the engine lost power after
>>     takeoff,
>>     the light was on.  However, I'm not sure fuel starvation is the reason
>>     for the power failure.  There's 4.9 gallons in that sump.  That's
>>     a lot
>>     of time, and there is no way I could have emptied it.  The other
>>     theory
>>     is that I was running too rich.  The electronic injection system was
>>     tuned out to 2250 RPM's, because that's the limit I could do in ground
>>     testing.  I then extrapolated out to 3000 RPM's (red line at
>>     2800), and
>>     then richened up the whole table to be on the safe side.  One thing I
>>     wish I had done during high power testing was to see how much more
>>     rich
>>     I could go before killing the engine.  I pulled the spark plugs,
>>     and the
>>     plugs closest to the firewall were very sooty.  The other four plugs
>>     looked very good.
>>
>>     After 12 years of building, it looks like I have a little bit more to
>>     go.  The belly of the plane looks good.  The compression buckling
>>     worries me as to how I will fix that.  The wings are also showing
>>     compression buckling just outboard of the spar attach bolts.
>>
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>>
>>
>>
>> -- 
>> All the best,
>> Dennis
>> ------------------------------------------------------------------------
>>
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