RV-3 Flight Number Two?.There is a Reason We Prepare!

[KiloWhiskey1]

My DAR required that I stay over the airport for the first 8 hours. I will add this to my test flight prep for any new planes I might fly. No matter how many ground runs you make, you can't be certain how the engine, hoses, electrical, etc. will respond to takeoff power, vibrations, and relative wind of typical flight conditions.

Not sure if 8 hours is the right threshold, but I would suggest at least 5-10 flights. If you're concerned about engine break-in, then just climb and orbit knowing that you are an easy glide away from the safety of a runway and your own hangar.


Keith

[vic syracuse]

Very well executed Paul! Job well done. It is for this very reason that I have 2 rules I won't break on the first 5 hours of all test flights: I won't go beyond power-off gliding distance of the airport and I won't switch fuel tanks in flight until several flights have been made on each tank. I'd rather be close to the emergency equipment if needed and I don't trust mine or anyone else's workmanship until proven otherwise.

Vic

[Ironflight]

I like (and agree with - it's in my plan) the idea of staying within gliding distance of a "landing site" at all times in the early phases - definitely. However, that can be a little impractical when you live under a 2,000' Class B floor - so rather than the absolute being "near the airport", the real rule is "near a safe landing area".

Now what is your criteria for leaving the vicinity of the airport? I've seen five hours, eight hours....sort of arbitrary, aren't they? How about "have exercised all the functions that might cause the engine to quit (i.e. fuel tank switching, feeding from each tank, boost pump on/off, ignition redundancy., etc) and "X" number of visual FWF inspections without any leakage or visible component wear? Arbitrary hour limits don't really mean anything, and can be argued. Concrete criteria (with rationale) is far better.

I think maybe we'll start filling up this "Flight Test" forum a little more!

Paul

[vic syracuse]

I agree on the arbitrary 5 hours, but here's my reasoning for a minimum of 5. Usually, and I say usually, experienced pilots can get through all of the flight characteristic profiles and new engine operations within that timeframe, and sometimes even sooner. However, I find that it takes about 5 hours for everything to become second nature when/if the anomaly occurs, such as remembering to fly the airplane, not start fiddling with everything, and being able to recognize what attitudes give what airspeeds, etc.
We should start a thread just on this. Right now I have to get to a meeting.

But again, great job!

Vic

[jjconstant]

I want to test the characteristics of the in-between position on the Andair fuel valve in flight. On another thread it was pointed out that a difference between 2 different models of Andair valve is that one has a detent on Both and the other doesn't. Further, Andair cites a reduction in fuel in the off-center position on the one without.

What do you think about setting up in 65 percent cruise, in gliding distance of an airport, but with a full rich mixture. Note fuel flow and EGT. Then move it to directly in between Left and Right and note the fuel flow/EGT, and then move to either side of directly in between, noting if there are changes in fuel flow and where they occur. Would this work? Is reducing the fuel flow at the valve similar to leaning the mixture with the same indicators in fuel flow and EGT? I'm thinking full rich mixture at 65% so if it goes way lean but still running I'm not damaging the engine.

Jeremy Constant

[RVbySDI]

Originally Posted by jjconstant

I want to test the characteristics of the in-between position on the Andair fuel valve in flight. On another thread it was pointed out that a difference between 2 different models of Andair valve is that one has a detent on Both and the other doesn't. Further, Andair cites a reduction in fuel in the off-center position on the one without.

What do you think about setting up in 65 percent cruise, in gliding distance of an airport, but with a full rich mixture. Note fuel flow and EGT. Then move it to directly in between Left and Right and note the fuel flow/EGT, and then move to either side of directly in between, noting if there are changes in fuel flow and where they occur. Would this work? Is reducing the fuel flow at the valve similar to leaning the mixture with the same indicators in fuel flow and EGT? I'm thinking full rich mixture at 65% so if it goes way lean but still running I'm not damaging the engine.

Jeremy Constant

I think you have spelled out a well thought out test. Yes, at 65% there would be little risk. Even so, if you are monitoring the EGT's while doing this you would quickly notice if the mixture is leaning out. I would not expect you would have to fly in this state for very long before you would notice some kind of result if there was a decrease in fuel flow.

If you do run this test, I would be very interested in seeing your results.

[Mike S]

Originally Posted by jjconstant

What do you think about setting up in 65 percent cruise, in gliding distance of an airport, but with a full rich mixture. Note fuel flow and EGT. Then move it to directly in between Left and Right and note the fuel flow/EGT, and then move to either side of directly in between, noting if there are changes in fuel flow and where they occur.

Jeremy Constant

Why not just do this on the ground????

[Ironflight]

Originally Posted by Mike S

Why not just do this on the ground????

Bingo! A WHOLE lot less risk that way....

[LifeofReiley]

I have the same pointer and mine came with two long set screws(top and bottom)... I used a dab of blue loctite and set both tight... even left them a little long as a reminder to check them every now and then.
I guess one could mark and file a flat for one set.

Good Job Paul!

[vic syracuse]

You don't even have to run the engine for this test. Just disconnect at the engine, use the electric pump, and watch the change on the fuel flow gauge if you have one.

Vic