REFLECTOR: Engine failure causes

[Brian Michalk]

Bill,

I was doing high speed taxi tests. Full throttle to speed, then yank 
power, then raise nose. All testing done with power off. I called my 
technical flight adviser, and he strongly suggested to not do anymore 
taxi testing. I felt my taxi testing was safe. Never got close to 
running off the end of the runway. I even think I had enough cushion to 
take a short hop.

I have had a bit of engine run time on the plane. I never once 
experienced a loss of power caused by the system. I think my logbook 
will show maybe eight days of engine runs accumulated before I ever got 
to the airport.

Stockman, Bill wrote:
>
> Brian
>
> When you test your aircraft, you need to run it on the ground for a 
> minimum of one to two hours (not continuous). You also needed to have 
> tied it down and raised the nose to simulate climb and run it in that 
> position for 5-10 minutes (obviously make sure the propeller is 
> clear). It’s amazing how much junk, water, resin, sanding grit, gets 
> in the tanks, fuel lines, etc that doesn’t show up until you fly and 
> climb out. Unless you have run the engine or drained the sump in a 
> nose high (or any unusual) attitude, you may never find the water that 
> has accumulated in your tank over the last few years. Also, our local 
> EAAs recommend 15-20 high speed liftoffs at full power (pop it off the 
> ground and then land straight ahead). This becomes very important if 
> you have changed the standard set ups and installations—this means you 
> get to be real test pilot flying a new design.
>
> You also need to consider blocked vent lines. I realize you had 
> minimum gas in the tanks, but if the main internal vents are plugged 
> up (with debris or gas) the system will not draw fuel. This can bite 
> folks since they also check this with the plane level but not with the 
> plane in a nose high attitude. After flying almost 500 hours in mine, 
> I filled my tanks to the max one day prior to a cross country and 
> found that one of the tanks would no longer feed fuel (I landed, 
> popped the cap and things equalized enough after about ten minutes to 
> continue the trip—I blew the system out when I returned home). I 
> apparently had too much gas and totally plugged the vent system with gas.
>
> Good luck.
>
> Bill Stockman, Senior Associate
>
> Dayton Aerospace
>
> (937) 369-4799 cell
>
> (937) 426-4300 work
>
> bill.stockman at daytonaero.com
>
> ------------------------------------------------------------------------