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ricksked(at)embarqmail.co
Guest

Posted: Sat Apr 26, 2008 5:58 pm Post subject: RV10-List:

I think I heard it run.... LOUD....not sure if it was theirs or not but the test cell at SUN N FUN was very active after 5 pm. If you thought the airshow made noise...jeeeezz. 

Rick Sked 

40185 

do not archive

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ricksked(at)embarqmail.co
Guest

Posted: Sun Apr 27, 2008 6:45 am Post subject: RV10-List:

If you go with a purge valve there is a return line that can be run in several different ways. Mine runs back into the fuselage and tees off at the right tank oulet, no modificatin to the tank but do the line while your plumbing the brakes. The line has a check valve installed so the fuel can only go back to the tee and then into the tank. Procedure is to switch to the left tank, open the purge valve and run the boost pump. Cool fuel runs from the left tank and into the purge valve then into the right tank. Cools the spider to prevent vapor lock. The purge valve is also used to shut down the engine instead of pulling the mixture. It shuts the fule off the the injector lines. I used a throttle control cable on mine and a return spring on the control arm incase the cable fails it will hold the arm in the closed position. I think the valve should be treated as a critical control on the aircraft so no lawn mower pulls for me. 

Rick Sked 

40185

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Kelly McMullen

Joined: 16 Apr 2008
Posts: 1188
Location: Sun Lakes AZ

Posted: Sun Apr 27, 2008 7:24 am Post subject: RV10-List:

I alway wonder about the concerns for vapor lock and hot starts that

apparently is the justification for return lines. I've been flying an

IO-360 in my Mooney for 10 years now, and never had more than minor

inconvenience on hot starts if I screw up a bit. It should be just as

prone to those problems as any RV, with tight cowling and stock RSA

Bendix/Precision fuel injection. That includes flying through the

summer each of those years in Aridzona. I just can't see the benefit

for adding that complexity and potential additional failure points.



On Sun, Apr 27, 2008 at 7:41 AM, Rick Sked <ricksked(at)embarqmail.com> wrote:

[quote]



 If you go with a purge valve there is a return line that can be run in

 several different ways. Mine runs back into the fuselage and tees off at the

 right tank oulet, no modificatin to the tank but do the line while your

 plumbing the brakes. The line has a check valve installed so the fuel can

 only go back to the tee and then into the tank. Procedure is to switch to

 the left tank, open the purge valve and run the boost pump. Cool fuel runs

 from the left tank and into the purge valve then into the right tank. Cools

 the spider to prevent vapor lock. The purge valve is also used to shut down

 the engine instead of pulling the mixture. It shuts the fule off the the

 injector lines. I used a throttle control cable on mine and a return spring

 on the control arm incase the cable fails it will hold the arm in the closed

 position. I think the valve should be treated as a critical control on the

 aircraft so no lawn mower pulls for me.



 Rick Sked



 40185



 ---

_________________
Kelly McMullen
A&P/IA, EAA Tech Counselor
KCHD

dlm46007(at)cox.net
Guest

Posted: Sun Apr 27, 2008 7:53 am Post subject: RV10-List:

So far hot starts have not been a problem. I have just cracked the throttle,

prop forward and mixture at idle cutoff. Start crankning and advance the

mixture and it starts instantly. 



--

gerf(at)gerf.com
Guest

Posted: Sun Apr 27, 2008 9:23 am Post subject: RV10-List:

Have to disagree with you there.  Yesterday when returning to KHAF in my

RV-9 I had to pull up and shutdown after landing to pull a barrier across

the taxiway to one side (it's the annual "Dream Machines" event where the

county turns the field into an obstacle course for pilots).  I could hear

the fuel gurgling under the cowl.  After about 10 minutes I jumped back in

and cranked and cranked and cranked - nothing - the fuel had boiled off in

the heat soaked cowl.  AFP fuel purge to the rescue !  I pulled the purge

valve and ran the boost pump for about 30 seconds - ignition on, crank,

close purge valve and she fired right up.



As for complexity - I don't see the argument.  There's one valve which is

open from startup to shutdown - what's the failure mode ?  If its going to

fail it will be on the ground when you are operating the valve at startup or

shutdown.



I've flown the Bendix ignition and the AFP I currently have installed on my

9.  My RV-10 will be fitted with the AFP return valve, that's for sure.



g



--

wcurtis(at)nerv10.com
Guest

Posted: Sun Apr 27, 2008 10:40 am Post subject: RV10-List:

So that begs the question.  If you had a standard Bendix type fuel injection system on that Lycoming, would you have had that same "fuel gurgling" and "hot start problem?"

With the AFP system, there is more fuel "above" the engine in the bigger fuel spider and purge valve than the standard Bendix/Precision type fuel system.



A lot of folks that are adamant about the installation of purge valves use "improved hot starts" as a justification. I fly behind a Lycoming angle valve IO-360 with a Bendix fuel injection and hot starts are a non-issue even on the hottest days. If you have a Lycoming engine with a Bendix type fuel system and have a "hot start" issue, then the "technique" needs to be worked on. For me it is, no prime, mixture to ICO, throttle 1/4 and just crank the engine. Engine ALWAYS starts in 2-3 blades.



There have been a few aircraft brought down because the builder/operators have failed to safety wire the stop on the purge valve.

http://img401.imageshack.us/img401/7280/dsc00248yu1.jpg

This is a classic case of the law of unintended consequences. In an effort to try to avoid one problem, an additional --more severe problem is introduced.



Some related information:

http://www.vansairforce.com/community/showthread.php?t=14998&



William

http://nerv10.com/wcurtis/ 



------

ricksked(at)embarqmail.co
Guest

Posted: Sun Apr 27, 2008 11:13 am Post subject: RV10-List:

Willaim,



I agree totally!! Technique is the best method but in a pinch...purge away, I live in Las Vegas...bit warm here in the summer...and...well, It came with my AFP system so instead of putting it in a baggie and sit it on the shelf...I used it. I do agree that it is an additional risk factor, but if installed properly,inspected and maintained it is as much risk as using nylocks on control surfaces...I still have not accepted that with open arms yet....but how many have failed? I never heard of one, so lets crank it up a notch...how many of you are reusing them over and over on the build? I have a set I use for mock up only, final assembly will get all new ones.



Rick Sked

40185

Polishing the baffels

---

gerf(at)gerf.com
Guest

Posted: Sun Apr 27, 2008 11:50 am Post subject: RV10-List:

Like I said I've flown behind both, for my money the purge valve is a great

addition to the engine.



I'm not adamant about the installation - take it or leave it as suits your

application.  I really like having it on my plane.



I've heard the "risk factor / point of failure" arguments before, but

they're not generally supported with a description of a incident that

illustrates.  What is the failure mode in flight that will threaten one's

safety ?



Totally agree with you about good technique as applied to a system where its

appropriate/needed.  The AFP system doesn't need the technique.  One less

thing to fuss over ...



g



--

Tim Olson

Joined: 25 Jan 2007
Posts: 2882

Posted: Sun Apr 27, 2008 12:39 pm Post subject: RV10-List:

But, specifically the RV-10 IO-540.....



In 330+ hours, I haven't yet had a problem with hot starts.  I've flown

on hot days, and had to restart, but just by using the normal hot start

procedure I've always had good luck.  Now, my comments are limited

to the IO-540, in an RV-10 installation, using a precision fuel

injection system.  If someone wants to use the AFP fuel injection

system....great....but, you may then have a good case for needing

a purge valve...I don't know.  They are 2 different systems.



Also, I have a lightspeed ignition, which has been a common install

on IO-540's.  So, perhaps someone with just dual mags may have

a small variation in results as well.



In short, all of those things affect how it may work for you, so

you need to be very specific about the exact situation that the

experiences you have come from.  There may be combinations that

work perfectly without, and there may be combinations that

definitely require it to be workable for hot starts.  I know

I'm very happy with the setup I'm using....for what that's worth.

Tim Olson - RV-10 N104CD - Flying

do not archive

Gerry Filby wrote:

[quote] 

 

 Like I said I've flown behind both, for my money the purge valve is a great

 addition to the engine.

 

 I'm not adamant about the installation - take it or leave it as suits your

 application.  I really like having it on my plane.

 

 I've heard the "risk factor / point of failure" arguments before, but

 they're not generally supported with a description of a incident that

 illustrates.  What is the failure mode in flight that will threaten one's

 safety ?

 

 Totally agree with you about good technique as applied to a system where its

 appropriate/needed.  The AFP system doesn't need the technique.  One less

 thing to fuss over ...

 

 g

 

 --

dlm46007(at)cox.net
Guest

Posted: Sun Apr 27, 2008 1:25 pm Post subject: RV10-List:

Agree on the nuts. I use all new MS21042 for final assembly control surfaces

and linkages. Someone will fly this airplane when I have become a sport

pilot. 



--

dmaib@me.com

Joined: 25 Apr 2006
Posts: 455
Location: New Smyrna Beach, Florida

Posted: Sun Apr 27, 2008 4:47 pm Post subject: RV10-List:

All new for final assembly, keep used ones for all of the "put it  

together, take it back apart, put it back together, ad infinitum" tasks.



David Maib

40559



On Apr 27, 2008, at 4:22 PM, David McNeill wrote:




Agree on the nuts. I use all new MS21042 for final assembly control  

surfaces

and linkages. Someone will fly this airplane when I have become a sport

pilot.



--

_________________
David Maib
RV-10 #40559
New Smyrna Beach, FL

Kelly McMullen

Joined: 16 Apr 2008
Posts: 1188
Location: Sun Lakes AZ

Posted: Sun Apr 27, 2008 7:05 pm Post subject: RV10-List:

That is the way I do it. Probably what worked for your old Cardinal as well.



On Sun, Apr 27, 2008 at 8:49 AM, David McNeill <dlm46007(at)cox.net> wrote:

[quote] 



  So far hot starts have not been a problem. I have just cracked the throttle,

  prop forward and mixture at idle cutoff. Start crankning and advance the

  mixture and it starts instantly.

  --

_________________
Kelly McMullen
A&P/IA, EAA Tech Counselor
KCHD

Ray.R.Doerr(at)sprint.com
Guest

Posted: Mon Apr 28, 2008 5:30 am Post subject: RV10-List:

I have 375+ hours on my IO-540 with dual slick mags and have done lots of hot starts with no issues.  Like it has been said before, technique is everything.  Throttle 1/8" to 1/4", Mixture at Idle Cutoff, no boost pump.  Crank and when it fires, get the mixture in right away and turn on the boost pump for a few seconds.  Once I did 10+ hot starts in a row while doing a prop balance, no issues.

Thank You

Ray Doerr

N519RV (40250)

Hopefully it will be out of the paint shop this Friday.



--

n212pj(at)gmail.com
Guest

Posted: Mon Apr 28, 2008 5:34 am Post subject: RV10-List:

Is everyone using the bottom cowling vents?  This might aid in air

circulation on the ground leading to somewhat better cooling?  I have no

idea what I'm talking about, but might be another data point.  



John Jessen



Do not archive 



--

jim(at)CombsFive.Com
Guest

Posted: Mon Apr 28, 2008 2:54 pm Post subject: RV10-List:

Check with Alex De Dominicis.  He has them on his RV-10.  Engine seemed to run much cooler.  He sells the vents.



I was there last week doing some RV-10 training.  My first time in an RV-10.  I am a low time pilot.  Really good for me.  I highly recommend the training.



While we were doing pattern work.  Someone at the airport asked for a set to be used on a Lancair.



Jim Combs

N312F

(40192)



============================================================

From: John Jessen <n212pj(at)gmail.com>

Date: 2008/04/28 Mon AM 09:31:45 EDT

To: <rv10-list(at)matronics.com>

Subject: RE: RV10-List:






Is everyone using the bottom cowling vents?  This might aid in air

circulation on the ground leading to somewhat better cooling?  I have no

idea what I'm talking about, but might be another data point.  



John Jessen



Do not archive 



--

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