Replies to This Discussion

Permalink Reply by Jimmy Young on April 16, 2017 at 6:48am

Hi John,

I'd like to see a photo of the fuel filter set up you described, if you could post one for us.

JY

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Permalink Reply by John Austin on April 16, 2017 at 7:14am

Jimmy,

I just got the console side covers secured (about a dozen screws at least!) and then I remembered I had neglected to take any pics, darn it!  I'll certainly take some the next time I have the cover off, but that may be a while as long as all goes well.  I'll probably fly this afternoon and see if I can get a pic from forward of the console looking back between the side cover panels.

However, maybe I can construct a "word picture for you." Here's what the Jeg's filter looks like:

The billet alluminum body is 2 5/15" long, not including the fittings.  I screwed it directly to the outlet port on my Andair fuel valve - it's the one with the banjo fitting in this construction pic:

I just had to rotate the banjo fitting to about the 5 o'clock position so the filter and attached line now run down the inside of the console cover on the pilot's side.  This line arcs down and then forward along the floor to near the firewall, arcs right and is connected with a 90 degree fitting to a bulkhead fitting on the passenger's side of the firewall.

I really like this positon better, anyway.  With my original idea to mount it just inside the firewall, I would have to snake up under the panel to get to it for annual inspection and cleaning.  Now, I can comfortably sit on a stool beside the plane, reach in and remove the console cover, and there's the filter!  One less backache! Ha! Also, although my firewall is insulated, I'm sure it's a few degrees cooler behind the console vs the inside of the firewall.

Hope this helps.

John

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Permalink Reply by John Austin on April 16, 2017 at 12:48pm

I made some pics without removing the side panels on the console! :>)

Here's the filter - I wrapped a piece of silicone self-fusing tape around the bottom of it because it was very close to the connectors on the back of my flap switch.  Although the connectors are insulated, I just thought it best to ensure there was no possibility of fretting and shorting:

From there, the fuel line runs forward through the tunnel created by the support I fabricated to support my pitch servo (I have dual sticks which have a bellcrank at the forward end of the center console):

And, as previously described, the line then arcs right and terminates in a 90 degree fitting at the firewall bulkhead fitting:

John

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Permalink Reply by Mark Pensenstadler on April 17, 2017 at 11:45am

Looks like you're doing some heavy braking!!!

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Permalink Reply by John Austin on April 17, 2017 at 12:56pm

Nearly 5 years and 460+ hrs on those pedals!  ;>)  If you mean the pedal looks a little bent - that's just camera lens distortion - they're perfectly straight!  :>)

John

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Permalink Reply by John Austin on December 19, 2017 at 1:57pm

Jimmy,

I happened to have the left cover off my console today and remembered that some time ago you had requested a picture of my fuel filter setup.  I had a leaking Andair fuel valve and had to replace it, so I got one with an AN6 male fitting on the outlet to the engine.  I used a 45 degree AN6 female to AN6 male fitting to connect the fuel filter.

I really like this setup for its ease of access!

John

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Permalink Reply by Ernest Christley on May 26, 2017 at 4:55pm

Heh, John, concerning your "burps".  I had those on my Corsair equipped 601XL.  The solution for me was intake air temp.  I ran a probe under the filter and, because the Aerocarb pulls cowl air, was get 130*F.   I cut an cute little hole in my cowl, and built an air dam that encompassed the air filter, and just allow the cool air to flow around the filter and out the back.  Air blows on the filter, but it isn't "forced air".  Aerocarb doesn't like that either.  The results were that IAT tracked close to ambient, and I haven't had a burp since.  :-)

BTW, I accidentally order the wrong K&N filter.  Got one about 3" high and 5" across.  Figure, WTH, it will fit on the cowl.  Let's give it a try.  Cut out a couple plates of scrap left over from side skins to close off the ends and bolted it on.  I need to do more testing, but it's looking like an extra 100RPM above the little lawn mower filter that the manufacturer ships.

 

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Permalink Reply by John Austin on May 26, 2017 at 6:22pm

I think my problem was primarily the gascolator and fuel line getting heat-soaked and causing slight vapor in the fuel.  After deleting the gascolator, putting an inline filter inside the cabin away from the heat, and insulating and heat-shielding the fuel line, I've had no more problems with ambient air temps in the high 80's/almost 90F - not a single "burp!" I'm still pulling cowl air in the air filter, but it doesn't seem to be a problem. I've even slow-taxiied or let the plane idle for a few minutes after flight to see if the decreased cooling would induce problems, but it hasn't so far.

Fortunately, it usually doesn't get a whole lot hotter here in East Tennessee - it certainly will get into the 90's this summer but it's a rare day to hit 100 or more - guess that will be the ultimate test! The daily high was 92F at Sun 'n Fun this year when it "burped" so badly on the long taxi to homebuilt camping, but in retrospect, my arrival was in the morning and it probably was no hotter than mid-high 80's at the time, so maybe I've got it solved!

The K&N works great for me - I used the RU-0660 clamped right on the carb - didn't buy or try the filter that AeroConversions sells for the AeroInjector.  I see no difference vs the Bing on the high-end rpm's, but curiously, with the AeroInjector, the Jab 3300 will now idle at lower rpms - as low as 500+!  Of course, I've set my idle higher at about 700-800 just to be on the safe side!

John

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Permalink Reply by John Austin on June 23, 2017 at 9:43am

Update:

My latest configuration worked perfectly - not a single "burp" - even when we hit the low 90'sF until I flew to an EAA fly-in recently and the plane sat on the ramp for 2+ hrs in 90+ ambients. Much to my surprise, it then "burped" badly on start-up and taxi! It seemed to be getting better as I taxiied and I had a nice, long runway, so I advanced the throttle and once past about mid-throttle, it completely cleared and I had an uneventful flight home.  Once home, even with aggressive leaning on taxi or at idle, I could not get the engine to "burp" again.

Since I had insulated the fuel line, I think the carb became heat-soaked on the ramp, generating vapor. Kerry at Sonex/AeroConversions had previously pointed out to me that since I had elected to mount the carb with the fuel inlet at the top (top-right side from pilot's perspective), I still had a potential "trap" for vapor since the fuel flow has to turn back down to enter the carb. (I had mounted it that way because my fuel line comes through the firewall on the right side.)  What I think happened is that on start-up, the fuel flow "siphons" trapped vapor at the top of the carb, causing hesitations or "burps" until the fuel flow is sufficient to flush all the vapor through the carb.

So, the other day I rotated the carb 180 degrees, putting the fuel inlet on the bottom-left side of the carb.  This eliminates the trap and allows any vapor to naturally vent up through the carb and not accumulate.  I re-routed the "red cube" flow sensor and fuel line so that it is again in a continuous upward slope to the carb.  To make a smooth, upward transition from the fuel line on the right to the inlet on the left, I got an Earl's 150 degree fitting:

I also applied a piece of self-adhesive radiant heat barrier to the side of the carb facing the engine, fire-sleeved the fuel line, and covered it with the Thermotec radiant heat barrier:

A secondary benefit of this new installation is that the fuel line is even shorter and lower in the cowl - hopefully reducing potential heat-soaking of the fuel line.

Of course, as soon as I finished, it began raining and looks like it will continue for a few days. :>(   Looks like flight testing is delayed 'til next week when we dry out!

John

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Permalink Reply by John Austin on July 7, 2017 at 9:21pm

We were up to about 90F today, so I flew the plane and thoroughly warmed up the engine, then parked it on my concrete ramp in the sun for about 30 minutes to deliberately heat-soak the fuel system.  I then flew it again and there wasn't a hint of "burps" or hesitation.

So far, so good!

John

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Permalink Reply by Ernest Christley on July 8, 2017 at 1:14pm

Any hotter than that, and it is to hot to be sitting under that solar oven of a canopy anyhow.  :-)

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Permalink Reply by John Austin on August 2, 2017 at 4:24pm

As I seem to have reached my final configuration of the AeroInjector's fuel and induction system, I looked hard at the installation to see if any further refinements were necessary.  I was a little concerned about using the 2" o.d. rubber gas filler hose as an intake runner since the carb and air filter are suspended/cantilevered off the distal end.  Since the hose is rubber, I was concerned that the weight of the carb and filter might induce vibration.  So, I elected to make an aluminum intake runner of the same length.  (The truth is, I wanted to play with my lathe and mill!)  I obtained a like-new used intake flange:

I also obtained a 2" o.d. x 0.25" wall 6061T6 tube from McMaster-Carr.  One one end of the tube, I machined a groove to capture the rubber carb socket's rib and also tapered the i.d. to match the rubber carb socket's i.d..  The other end was then welded full-thickness (by a certified welder!) to the used flange - he did a great job - when I was cleaning up the inside of the runner, I could not detect the weld or a seam at all!

Once mounted, it looks like this:

(After this picture the carb was safety-wired to the intake runner and the fuel line was insulated and wrapped with Thermotec radiant heat barrier and secured with stainless tie-wraps.

The end result?  I now have a very precise mixture control and extremely well balanced EGT's/CHT's:

I'm a happy camper!  ;>)

John

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