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12-11-2011, 11:57 PM
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Senior Curmudgeon
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Join Date: Sep 2005
Location: Dayton Airpark, NV A34
Posts: 15,420
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Quote:
Originally Posted by Ironflight
?OK, I've just lost power ?
? the Whirlwind kept going round and round, but I had no throttle response.
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The above seems to indicate the engine was still running, not merely the prop windmilling.
If that is the case, my guess is throttle arm to throttle shaft screw backed off enough to allow the indexing teeth to disengage.
Other possibility is the quadrant end of the throttle cable, depending on how it is attached to the lever........
Either way, sounds like something between the pistol grip in your hand, and the butterfly in the induction throat.
__________________
Mike Starkey
VAF 909
Rv-10, N210LM.
Flying as of 12/4/2010
Phase 1 done, 2/4/2011 
Sold after 240+ wonderful hours of flight.
"Flying the airplane is more important than radioing your plight to a person on the ground incapable of understanding or doing anything about it."
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12-12-2011, 01:26 AM
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Join Date: Nov 2007
Location: Reno, NV
Posts: 2,125
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Notes below the quote box...
Quote:
Originally Posted by Ironflight
<snip> ?OK, I've just lost power ? going for a good glide speed.?
<snip> I calmly worked through the standard power loss checklist ? the Whirlwind kept going round and round, but I had no throttle response. I switched tanks several times, tried the boost pump, played with the throttle and mixture ? no joy.
<snip> I had about a forty minute wait for the ground team to arrive, and before it got dark, I had already figured out what had brought us down ? at least I was pretty sure of it.
<snip> It was a single screw backed out about ? turn.
<snip> Anyone want to guess about what screw? 
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Paul, first off, great flying...glad you are AOK. Second, Louise, in the debrief you have that look of a fully-engaged co-test-pilot, but I also see the same look of concern my wife would be giving me if I had just had an off-airport landing...I'm sure you are relieved...and proud of your guy!
I highlighted the notes I think may help solve the mystery above...some more telling than others:
Going for glide speed to me means total or near total power loss...perhaps.
Power loss checklist, not stuck throttle or non-responsive throttle checklist...maybe just semantics, but...
Why switch tanks and switch on the boost pump if the engine is running (versus windmilling)?
Not sure if Paul had tools on the test flight, but he had it figured before the ground crew arrived. Not sure if the pic is that afternoon or the next morning, but the cowl is still on.
I know a purge valve stop failure would shut it down as Kahuna says, but would that happen with the screw out 1/2 turn...dunno...wouldn't rule it out.
I did have a fuel selector come loose once, when my RV was newer-to-me. Switched tanks and a bit later noticed that fuel was still coming out of the same tank as before (that gauge still decreasing). Handle felt a bit loose, but it was still new to me, so rather than try to switch tanks again, and take a chance of it going halfway (to off), I RTB'd quickly. Sure enough, the screw was backed out enough to allow the handle to turn freely, and catch the key if pushed down while turning.
I was lucky...and had the motor quit, I would have been putting the boost on and changing tanks just like Paul.
I'm going with LoopFuz and Pooner this on this one (fuel selector), though Kahuna's sounds very feasible too.
Glad you got the gravel runway landing portion of your Phase I testing done without incident!  Whew
Best,
Bob
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12-12-2011, 03:45 AM
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Join Date: Dec 2005
Location: Sydney, Australia
Posts: 427
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My vote is a screw terminal on the electronic ignition.
Doug Gray
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12-12-2011, 05:02 AM
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Join Date: Jan 2005
Location: Louisville, Ga
Posts: 7,840
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Yep.
Quote:
Originally Posted by Kahuna
Any chance his IO 320 has an AFP purge valve? Often during installation the safety wire is cut on a couple of screws to mount the purge valve. There have been multiple failures of this where a set screws back out, causing the purve valve to go into by-pass, starving the engine of fuel. Ask me how I know.
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.....X 2. I bid on a -4 that was totalled following purge valve activation!
Best,
__________________
Pierre Smith
RV-10, 510 TT
RV6A (Sojourner) 180 HP, Catto 3 Bl (502Hrs), gone...and already missed
Air Tractor AT 502B PT 6-15 Sold
Air Tractor 402 PT-6-20 Sold
EAA Flight Advisor/CFI/Tech Counselor
Louisville, Ga
It's never skill or craftsmanship that completes airplanes, it's the will to do so,
Patrick Kenny, EAA 275132
Dues gladly paid!
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12-12-2011, 05:13 AM
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Join Date: Sep 2005
Location: Dayton, Nevada --- A34
Posts: 1,464
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Great thread
Well, this has flushed out some great discussion and I'm going to check a few more things the next time the cowl is off. Paul is still asleep and I'll let him do the big reveal, but I can answer a few questions while waiting for my AL mailing tube to depart.
Bob, not surprisingly, your incident analysis is excellent. The plane had loss complete power. Paul made the field repair with the one (and only) tool he happened to have with him. (There's another challenge for you. What tool happened to be in the cockpit? No, not the screwdriver on his Swiss Army knife.) The cowl did not come off in the field.
The engine is injected.
The photos are a little out of order. In the room is the pre-flight briefing. My expression is deep concentration on the briefing mixed with healthy concern/nervousness. Paul has a quote from famed test pilot John Young that I love. It is something like, 'If you aren't a little nervous before the first flight of a brand new aircraft, you don't understand what you are about to do."
I think this experience supports that statement. The field photo was the following morning.
Doors are closing so I have to go.
__________________
Louise Hose, Editor of The Homebuilder's Portal by KITPLANES
RV3B, NX13PL "Tsamsiyu" co-builder, TMXIO-320, test platform Legacy G3X/TruTrak avionics suite
RV-6 ?Mikey? (purchased flying) ? Garmin test platform (G3X Touch, GS28 autopilot servos, GTN650 GPS/Nav/Comm,
GNC255 Nav/Com, GA240 audio panel)
RV8, N188PD "Valkyrie" (by marriage)
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12-12-2011, 05:42 AM
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Join Date: Jan 2005
Posts: 1,009
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Glad You're Safe...
..and the outcome was good. Incidents such as this should give everyone that's finishing an aircraft a reason to pause and think. Am I qualified to test fly-especially the first few flights? Do I have a good "bail" area that will keep me and the aircraft safe?
My only criticism of this incident is the "guess why" if the answer is already known. Glad the FAA doesn't take this tack when they do accident/incident analysis. The objective should be to get the info out as quickly as possible to help someone else avoid having the same problem.
Terry, CFI
RV9A N323TP
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12-12-2011, 05:50 AM
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Join Date: Feb 2005
Location: Northwestern USA
Posts: 1,209
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Holy cow! Glad you and the airplane are okay. Looking forward to hearing about the presumed cause!
mcb
__________________
Matt Burch
RV-7 (last 90%)
http://www.rv7blog.com
VAF #836
Any opinions expressed in this message are my own and not those of my employer.
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12-12-2011, 05:54 AM
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Join Date: Jan 2005
Location: Arkansas
Posts: 1,505
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I like the "guess why" question. It has already shown up other possibilities that can and has caused a total loss of power. Now we all have more than one thing to check before flight on a new aircraft. The answer will come soon enough. Thanks Paul and so glad you and the plane are OK.
__________________
Jim Wright
RV-9A N9JW 90919 SoldArkansas
http://www.jimsairplanes.com
_______________________
"It's a brutal struggle for the biscuit."
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12-12-2011, 06:11 AM
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VAF Moderator / Line Boy
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Join Date: Jan 2005
Location: Dayton, NV
Posts: 12,256
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The Rest of the Story?.
OK folks, that little "information pause" just generated a number of things for all of us to check on our airplanes...didn't it?! Thanks for your patienece - I think the comments and analysis were good. (I liked the logical, methodical approach of the posts - now, can you do that thinking in the time it takes to lose 4,000' in a powerless short-winged RV? )We've had a little sleep (emphasis on little for Louise - she had an 0430 alarm for a business flight this morning...), so here's the deal -and pretty much everything that was guessed COULD have been a possible casue.
For those that said fuel Selector, you were right on – or close, depending on if you know the trick to this after-market fuel selector handle. This nice little addition to Van’s standard brass fuel valve has one (known and documented by the manufacturuer) shortcoming – it depends on a set screw to “key” it to the shaft. The standard handle from Van is cast with a solid key in the cylindrical hole so that it can only go on the valve’s shaft one way. But the nice anodized handle works on different vintage valves that have the “flat” of the shaft on opposite sides. You set it up once for your airplane. The countersunk Phillips screw that you see in the picture holds the handle on the end of the shaft, but doesn’t key it. The “flat” on the shaft is very shallow – backing the set screw out by a haf turn will allow the handle to spin on the shaft – rendering the valve useless, and stuck in it’s last position. The instruction clearly state to LocTite the set screw in place….and that is what I mean by the "thousands of details in building one of these planes". In this case, we do so many test fittings and removals; we never know when it will be the last one. So when do you Loc-Tite it? That’s what I hate about red LocTite – you have to be certain you’re done removing it. You never are, so it's easy to forget.
So what Happened to Junior? Well, I was doing laps, breaking in the engine, and it seemed like a good time to switch tanks to keep the tanks balanced. I’ve moved the selector many, many times since final assembly (including during ground engne runs) – but the screw must have been working its way loose, because when I turned the handle, it started to move the shaft, then the set screw slipped off the flat. The handle showed a selected tank, while the valve itself was stuck BETWEEN tanks – essentially in the “off” position. The engine stopped firing shortly thereafter, and nothing I could do would make it run. (The prop kept wind-milling through the flare BTW….) It wasn’t until I was sitting on the ground, waiting for the crew to arrive, that I turned the valve in the silence of the country road, and noted that I didn’t hear or feel that characteristic “click”. It was just light enough to see that the shaft wasn’t turning with the handle. Fortunately, I was carrying an Allen screwdriver that is used to pull avionics – and this set screw was the same size. In two minutes, I had the valve working again – but it was too dark to legally fly, so we waited until morning.
The lesson to be learned is this – no matter how many people inspect the airplane, stuff can (and will) get missed. We are imperfect humans building imperfect machines. Accept that. Plan your flight test ASSUMING (knowing!)that things will fail, and make sure that your backup plans are adequate. Expect the unexpected, and be ready to meet it. That is the mark of a good Flight Test team.
Paul
__________________
Paul F. Dye
Editor at Large - KITPLANES Magazine
RV-8 - N188PD - "Valkyrie"
RV-6 (By Marriage) - N164MS - "Mikey"
RV-3B - N13PL - "Tsamsiyu"
A&P, EAA Tech Counselor/Flight Advisor
Dayton Valley Airpark (A34)
http://Ironflight.com
Last edited by Ironflight : 12-12-2011 at 07:20 AM.
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12-12-2011, 06:14 AM
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Join Date: Feb 2006
Location: Austin, TX
Posts: 433
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Great job Guys (and Gal!) w/ plans "b" through "z" and executing on them! The "A Team" for sure. Remember what Hannibal always said at the end of each show? - "I love it when a plan comes together."
Quote:
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Originally Posted by Louise
What tool happened to be in the cockpit? No, not the screwdriver on his Swiss Army knife.) The cowl did not come off in the field.
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For the tool, my guess is a Philips located on the end of the sump draining inspection tool. On mine, I can swap rotate the bit and have a regular/slotted bit but I I don't recall any regular screws on the kits.
The fuel valve idea is interesting. Not being familiar w/ the Junior's exact h/w config, I did go out to the garage and found my old brass fuel value - complete w/ Philips head screw. I removed it and the handle was on pretty tight. I know it's keyed but perhaps it stripped out. Kinda hard for me to imagine that the handle's looseness hadn't been felt prior, though.
Quote:
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Originally Posted by Ironflight
... but I had no throttle response. I switched tanks several times ...
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Hmmm, Paul must be feeling the indent if he believes he's switching tanks.
I'm now not so sure on the fuel valve. Ok, so what else is easily accessible, presumably from the cockpit and presumably w/ a Philips head. Still pondering.....
I got it! "It was all just a bad dream." 
__________________
/\/elson
RV-7A Tip-Up
NW Austin, TX
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