REFLECTOR: Engine failure causes

Brian Michalk michalk at awpi.com
Mon Apr 6 13:15:59 CDT 2009


I did run the plane at full throttle on various occasions.

I also ran fuel flow tests about two months prior to flight with the 
airplane in a climb attitude.  I inspected the filters after this test, 
and they were clean.  My tests showed 60 gallons per hour regardless of 
the airplane angle, and we did this by timing how long it took to fill a 
five gallon gas can, so there was a lot of flow going on there.  This 
was with the electric pump only.  Adding mechanical pump would have 
increased the flow even more.

I don't think anyone would be able to do a quick full power hop on the 
runway.  The runway would need to be very long.  I only had 4000 feet to 
work with.  The power off hops were okay, but I was surprised at the 
increase in rotation distance with power on.  The thrust vector really 
kept the nosewheel stuck to the runway.

Stockman, Bill wrote:
> The key is, did you ever run the engine at full throttle (either in a
> pop up) or with the nose raised on the ground to simulate the takeoff
> angle?
>
> I discovered on my plane (173FGE) that after raising the nose and
> running the engine a while, I found some water and sediment stuff in the
> fuel sample and filter.   Apparently raising the nose significantly let
> it escape to the sump tank and to the engine.   Just a thought.     
>
> Bill Stockman, Senior Associate
> Dayton Aerospace
>  
> (937) 369-4799 cell
> (937) 426-4300 work
> bill.stockman at daytonaero.com
> -----Original Message-----
> From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
> Behalf Of Brian Michalk
> Sent: Monday, April 06, 2009 1:33 PM
> To: Velocity Aircraft Owners and Builders list
> Subject: Re: REFLECTOR: Engine failure causes
>
> 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
>>
>>
>>     
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