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  #11  
Old 03-19-2009, 12:13 PM
Dave_Boxall Dave_Boxall is offline
 
Join Date: Mar 2005
Posts: 182
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It's hard to avoid that "basking shark" look if you use the Wilksch supplied cooling pack. Still it does make us a little different from the other RV-9's

Weight is 473 kg, 1043 lbs. CG 76.9 Inches AOD. We have a Flightline Interior with leather & confor foam seats, no spare space in the panel (though we have the glove-box fitted), a massive battery (Odessey PC925) and an MTV-21 propellor.

The weather is looking good, so I'm hoping to fly off a few more test hours tomorrow!

Dave
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Dave Boxall
RV-9A / Wilksch WAM-120 diesel. Flying since April 09
Bath England
=VAF= membership dues paid April 2017
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  #12  
Old 03-19-2009, 02:13 PM
Righty Righty is offline
 
Join Date: Dec 2005
Location: Portland, Oregon
Posts: 58
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Dave,

Glad to hear of your safe and successful first flight. I have been following the WAM and your updates with keen interest and have appreciated your posts on the subject. I have a couple of questions for you regarding your installation.

How did you route your fuel return line and what size line did you use? I'm currently getting ready to close up my first tank and want to include a provision for a return line. I have long hoped that a workable diesel solution would come about before I get to the engine stage and I assume that these will generally require a return line.

In a previous posting, you once mentioned that capacitance fuel senders should be used with this installation. Why is this? Wouldn't float senders work fine with any fuel?

Any recent updates on Wilksch? Still the same 1 year old stuff on their website.
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RV9A Standard Kit (wings)

Last edited by Righty : 03-19-2009 at 03:08 PM. Reason: 1 year since updates, not 2.
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  #13  
Old 03-19-2009, 03:42 PM
Dave_Boxall Dave_Boxall is offline
 
Join Date: Mar 2005
Posts: 182
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Quote:
Originally Posted by Righty View Post
How did you route your fuel return line and what size line did you use? I'm currently getting ready to close up my first tank and want to include a provision for a return line. I have long hoped that a workable diesel solution would come about before I get to the engine stage and I assume that these will generally require a return line.

In a previous posting, you once mentioned that capacitance fuel senders should be used with this installation. Why is this? Wouldn't float senders work fine with any fuel?

Any recent updates on Wilksch? Still the same 1 year old stuff on their website.
Our return line is -4 aluminum tubing (the same as the tank vent lines). It runs parallel with the main fuel line back through the fuselage and via an Andair dual valve. The line goes back into the tank via a bulkhead fitting in the tank end rib just below the fuel vent fitting. Our return fuel flows were at the low end of the acceptable range, and maybe a -6 line might have been better.

The capacitance sensors are a requirement of the LAA (the regulators for homebuilds in the UK). There is a theoretical explosion risk with jet fuel tanks and we were required either to fit through flow venting or to remove the resistive sensors because of the risk of sparking in the tanks.

Wilksch are developing a "big bore" version of their 3 cylinder engine which will weigh the same, but produce around 145hp. They currently have around a 20 engines flying (we're the 6th RV-9). They've stopped marketing "retail" engines as homebuilders need a ton of support & won't order the volume required to make production economic. I think they're working on getting an airframe manufacturer to install the engine and order some volume.


Dave
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RV-9A / Wilksch WAM-120 diesel. Flying since April 09
Bath England
=VAF= membership dues paid April 2017
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  #14  
Old 03-19-2009, 04:12 PM
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frankh frankh is offline
 
Join Date: Jul 2006
Location: Corvallis Oregon
Posts: 3,547
Default Eh?

A thoeretical explosion risk with jet fuel and not with say Mogas, using resistive sensors?

Surely kerosene has a higher flash point than petrol does? So why is there an increased risk?

Not sure I understand the comment on the return line being too small?...Does this engine have a fuel injection pump like regular diesels do?..if so the fuel will either go to the return or to the engine..In other words the FI pump will simply increase the pressure to return the fuel to the tank..In other words the return line should be just fine.

Frank
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  #15  
Old 03-19-2009, 04:25 PM
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airguy airguy is offline
 
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Location: Garden City, Tx
Posts: 5,842
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Gasoline has a much higher vapor pressure than jet fuel, and will very quickly develop a vapor mix in the tank that is too rich to burn or explode. Jet fuel evaporates more slowly and can, theoretically, form explosive mixtures in the tank. NTSB decided this is what brought down TWA800. Flow-thru venting will keep the mixture too lean to explode.
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Greg Niehues - SEL, IFR, Repairman Cert.
Garden City, TX VAF 2022 dues paid
N16GN flying 1,000 hrs and counting on 91E10; IO360, SDS, WWRV200, Dynon HDX, IFD440, G5
Built an off-plan RV9A with too much fuel and too much HP. Should drop dead any minute now.
Pending Repeat Offender - 10 kit is on order. TDI? Turbine? Stay tuned!

Last edited by airguy : 03-19-2009 at 04:27 PM.
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  #16  
Old 03-19-2009, 04:29 PM
Righty Righty is offline
 
Join Date: Dec 2005
Location: Portland, Oregon
Posts: 58
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Quote:
Originally Posted by Dave_Boxall View Post
snip

Wilksch are developing a "big bore" version of their 3 cylinder engine which will weigh the same, but produce around 145hp. They currently have around a 20 engines flying (we're the 6th RV-9). They've stopped marketing "retail" engines as homebuilders need a ton of support & won't order the volume required to make production economic. I think they're working on getting an airframe manufacturer to install the engine and order some volume.

snip
This sounds like a winner for the 9. I would question the decision not to market to homebuilders. I wonder if this means that they will refuse to sell to hombuilders, or they are just not actively marketing to them? Don't homebuilders account for at least half of the light airplane production (in the States anyway)?

It would seem they are passing up on a big portion of the market. Seems like it would make sense to identify the most popular homebuilts and try to develop FWF kits for them that would reduce the support requirements. Trying to secure an airframe manufacturer is great, but it puts all your eggs in one basket. Working with homebuilders would seem to reduce the risk of the bottom suddenly dropping out if your one and only client decides not to buy your product anymore or if you can't find that one and only client in the first place. Not to mention that homebuilders could provide a lot of free track record development (assuming successful installations) which would be a selling point for them when approaching an OEM.

I wish them the best, but this choice just doesn't make sense to me. They should be eager to have anyone installing their engines and do their best to ensure that those installations are successful. I guess I'll just keep pounding rivets and wait to see how things develop and hope for something truly modern like this to finally make it to prime time before I need to choose an engine.
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RV9A Standard Kit (wings)

Last edited by Righty : 03-19-2009 at 04:32 PM. Reason: ? about capacitive answered in intervening posts.
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  #17  
Old 03-19-2009, 04:34 PM
Righty Righty is offline
 
Join Date: Dec 2005
Location: Portland, Oregon
Posts: 58
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Quote:
Originally Posted by airguy View Post
Gasoline has a much higher vapor pressure than jet fuel, and will very quickly develop a vapor mix in the tank that is too rich to burn or explode. Jet fuel evaporates more slowly and can, theoretically, form explosive mixtures in the tank. NTSB decided this is what brought down TWA800. Flow-thru venting will keep the mixture too lean to explode.
This makes sense. So how does flow-thru venting work? Is fresh air forced into the tank somehow? How do diesel cars deal with this?
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RV9A Standard Kit (wings)

Last edited by Righty : 03-19-2009 at 06:46 PM.
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  #18  
Old 03-21-2009, 12:15 AM
Dave_Boxall Dave_Boxall is offline
 
Join Date: Mar 2005
Posts: 182
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On a small aircraft flow through venting seems to use one forward facing and one rearward facing tank vent. Air enters the tank via the forward facing vent & leaves through the rearward facing. You arrange the vent ports inside the tank to purge the vapour space.

I don't think Wilksch are planning to abandon the homebuild market, but making 20 engines a year for homebuilders isn't economic and expanding sales to several hundred engines is a big step up.

Dave
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Dave Boxall
RV-9A / Wilksch WAM-120 diesel. Flying since April 09
Bath England
=VAF= membership dues paid April 2017
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  #19  
Old 03-22-2009, 01:50 PM
Dave_Boxall Dave_Boxall is offline
 
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We have some better numbers now.
We have a total of 9 hours.
TAS at 5900 ft at a "steady cruise power" is 126 knots.
Climb rate is about 950 ft / minute at full power.
Average fuel burn so far is around 15 litres / hour (4 US gallons / hr).

Dave
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Dave Boxall
RV-9A / Wilksch WAM-120 diesel. Flying since April 09
Bath England
=VAF= membership dues paid April 2017
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  #20  
Old 03-30-2009, 09:41 AM
kgood kgood is offline
 
Join Date: Mar 2009
Location: Boulder City, NV
Posts: 168
Default RV9 / WAM 120

I also have an RV9 (tail dragger) with a Wilksch diesel. I first flew it in November '08, and have had excellent results so far. I am experiencing the same kind of performance numbers as Dave describes, and I have yet to install my gear leg fairings and wheel pants.

The Wilksch factory people have been very supportive and cooperative as I've tried to perfect my cooling system to be prepared for the Nevada heat I have to deal with. I've got it working well now, with plenty of margin for hot summer days.

I installed the standard resistive fuel sending units - I was not aware that there could be a potential problem. I have standard vents as well. I have logged 24 hours so far with no problems. I have done diesel conversions in several vehicles over the years, and have never had a problem. The Chevy Duramax trucks use the same type sending units. If anyone has any advice for me, I'd sure appreciate hearing it.

I have not yet put Jet A in the tanks. I've been flying on red diesel, which is costing me $1.62 / gal right now. Pretty cheap flying.

This weekend I flew it to the Alternative Engine Fly-in at Jean, NV. It sure generated a lot of interest. It took awhile for most folks to figure out it was an upside-down 3 cyl, turbo-intercooled diesel!
Kurt
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