• Welcome aboard HomebuiltAirplanes.com, your destination for connecting with a thriving community of more than 10,000 active members, all passionate about home-built aviation. Dive into our comprehensive repository of knowledge, exchange technical insights, arrange get-togethers, and trade aircrafts/parts with like-minded enthusiasts. Unearth a wide-ranging collection of general and kit plane aviation subjects, enriched with engaging imagery, in-depth technical manuals, and rare archives.

    For a nominal fee of $99.99/year or $12.99/month, you can immerse yourself in this dynamic community and unparalleled treasure-trove of aviation knowledge.

    Embark on your journey now!

    Click Here to Become a Premium Member and Experience Homebuilt Airplanes to the Fullest!

Getting my S-IIL flying again.

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

John B

Well-Known Member
Joined
Jun 9, 2013
Messages
222
So I've got it in the barn, parts ordered and have started working on getting my Sonerai IIL, N109JB, back in the air.

She first flew in 1992 and I flew it pretty often for several years. Then kids, career, moving here, moving there, etc. I did get it flying again in 2002 but there were a lot of things I wanted to change. I brought it home about 2005 but still had a PA-30 to fly so didn't ever get really serious about it. Before I knew it 2016 rolled around. I had sold the PA-30 and worked hard over there summer of 2016 to get her ready. Just about had her ready to go when it got cold so I planned to wait until spring 2017 to fly. Well, on 12-30-2016 my mom passed away and my father was not in good health. On top of that they had their house plus 6 other properties so all of 2017-2018 was taken up by dealing with selling properties, moving my dad, etc. I just couldn't get motivated to get 109JB ready even though she didn't need a ton. Well in August last year I decided I just needed to buy a ready to fly airplane and i jumped on the Kitfox craze and now have a flying Kitfox IV. I guess I just had to get into the seat again because I now have the Sonerai at home and am well on the way to getting her flying. I'm sure it will be ready before the end of the June. I also bought a salvage Kitfox IV Speedster for cheap that I'll be rebuilding after the Sonerai is flying.

Over time she has undergone a lot of mods. She started out pretty stock but has since been converted to single seat, had the fuselage shortened to accommodate a "standard" engineer mount, the fin and rudder were enlarged a little, she has gone from tailwheel to nose wheel and back to tailwheel. Fuselage recovered once along the way. Wings got repainted in 2016. Reshaped the turtledeck. And I'm sure more I've forgotten. Here are some pictures from about 2004. Looks pretty much the same now. I'll have more pics as the work progresses.

2004-06-25 @ 16-44-42  0816mod (3).jpg

2004-06-25 @ 15-17-21  0790.JPG
 
I've been working as much as I can on getting my Sonerai back in the air. Today I got to the point of running the engine. Some tuning to do for the new carburetor as it leans out with throttle. Nice to hear it run again though.

 
So as I posted a little while ago in my Aerinjector thread, I got the Aeroinjector yesterday and got it mounted and the engine running and tuned today. It was a long day and I got it out to the airport and got the wings back on it. That was about all I could get done today. Here is a picture of how I left it at the hangar with my Kitfox. Just a few things to sort out and I should have it flying, maybe even tomorrow.20200815_163218.jpg
 
My elevator trim tab is say 1 foot X 4". Piano hinge at top, Hinge at 45 degrees. / ,
If your CG is perfect and your stab setting is perfect then the tab is adequate. But if you didn't reset the stab incidence for a pax or guessed wrong, then it's not. I ended up installing an electric stab trim, with a 100:1 bellcrank to allow for stab adjustment with Pax or fuel changes. I like the idea of it but it;s scary to use in flight. Even though changes are minute, the whole aircraft jumps when you toggle the stab trim switch. Can't find a stab trim photo right now.
Thus I'd consider a larger elevator trim tab. Certainly wider, maybe with greater length. Say it's 48 sq in now, I might consider doubling that. Bill E

Need to fab up an elevator trim cable bracket and it's readyView attachment 15100
 
Bill,
You misunderstand. I didn't have a question about trim tabs as my airplane already has 300+ hours with one and it works fine. To expound, the tab is neutral in cruise flight meaning the stab incidence is set appropriately. The tab is about 12" wide and roughly 3 inches deep. It is integral to the elevator. My trim is manually actuated with a push pull cable and I just needed to fabricate a bracket because I was never happy with the old bracket. The manual actuation works very well and is not too sensitive.
 
So my Sonerai was airborne once again today. Takeoff and landing were a little spirited shall we say. Even though I have quite a bit of time in this airplane, it has been about 10 - 15 years since it last flew, and I also have been flying a Kitfox recently which is a much different airplane with the Sonerai being much more responsive to control inputs. As a consequence there was a bit of over-controlling, but all ended well and the airplane is still in one piece.

I did have an issue with the engine however. Everything was running well, the engine was performing as expected with the narrow band air-fuel ratio gauge (see picture) showing the 2nd green bar (about 3 o'clock on the gauge), but about 15 minutes into the flight I noticed some roughness and the A/F ratio gauge would go from the 2nd green bar to full lean momentarily and then back up to the 3 o'clock position. This got a little worse so I headed back to the airport and set up a high and slightly hot approach (6000 ft runway). When I finally pulled the throttle to idle during the flare the engine quit. I am thinking it is heat related. The carb draws air from the lower part of the cowl after it has gone through the engine cooling fins. My airplane also does not have the short exhaust stubs but has 4 long individual pipes that exit the bottom of the cowl. All of this makes for a good amount of heat down there.

Now it is possible that it is something else beside heat. The gascolator is my only fuel filter but it does have the fine screen installed instead of the normal coarse one. I'll check for any obstructions in the fuel system as well as install an inline filter. I also have premium unleaded auto fuel in the tank, but it is the same brand fuel that the airplane used previously without problem, although that was about 10 years ago. BTW, I do have foresleeve on the fuel supply line.

I see that the AeroInjector instructions caution against using ram air induction, so that is out, but I do have a plugged inlet underneath the oil pan cooling inlet. So I'm thinking about building a box around the aeroinjector to serve as a heat shield from the exhaust pipes. The box would have sides and a back but no front or bottom, and I would leave a gap between the cowl and the box so that it isn't totally sealed to the cowl. On the inlet at the front of the cowl the I would put a deflector so that there isn't a chance of ram air. getting straight into the carb. I could also wrap the exhaust pipes to reduce the heat coming off of them.

Has anyone else experience similar issues with the aerocarb, and if so what do you think of my proposed remedies.

Edit - forgot the picture if the AF gauge
4124XT43BCL._AC_.jpg
 
Last edited:
Has anyone else experience similar issues with the aerocarb, and if so what do you think of my proposed remedies.
Your problem may be heat related but here is another thing to think about. In a recorded discussion with Kerry Fores (Sonex) he mentions that auto fuel can have variable quality so suggests if you are having any kind of problem switch to Avgas. I am using Avgas exclusively now and everything is working as expected.
 
Your problem may be heat related but here is another thing to think about. In a recorded discussion with Kerry Fores (Sonex) he mentions that auto fuel can have variable quality so suggests if you are having any kind of problem switch to Avgas. I am using Avgas exclusively now and everything is working as expected.

I have definitely thought about this, but the engine ran for at least 30 minutes on the ground at all power settings and ran fine. It also ran fine for the first 10-15 minutes of flight just fine. The fuel didn't change at all during any of that. The fuel in the tank during the flight was the same fuel that was used for the ground runs. It seems to me that if it was a fuel quality issue the problems would have presented earlier in this case.
 
Mine exhibits similar but less severe behavior when the cowl is hot. The engine doesn't quit, in fact it never misses a beat during the flare and rollout, but if I taxi back for another takeoff it stumbles as I push the throttle forward. After one or two seconds though it gets its footing and off we go. Touch and go's can be positively puckering. Going 1/8 turn richer with the needle didn't seem to help but now that I think about it, maybe leaner is the way to go. When the airplane slows down and the cowl becomes heat soaked the Aerocarb is drawing pretty hot air and the mixture that worked for cooler air possibly won't work under this condition. Anyway, I'm still fiddling and will post again if I learn anything conclusive.

Ed
 
Mine exhibits similar but less severe behavior when the cowl is hot. The engine doesn't quit, in fact it never misses a beat during the flare and rollout, but if I taxi back for another takeoff it stumbles as I push the throttle forward. After one or two seconds though it gets its footing and off we go. Touch and go's can be positively puckering. Going 1/8 turn richer with the needle didn't seem to help but now that I think about it, maybe leaner is the way to go. When the airplane slows down and the cowl becomes heat soaked the Aerocarb is drawing pretty hot air and the mixture that worked for cooler air possibly won't work under this condition. Anyway, I'm still fiddling and will post again if I learn anything conclusive.

Ed

Thanks. I think I have a plan and after work today will be fabricating a heat shield and inlet to get cooler but not ram air to the carb. I'll report what I find.
 
I noticed some roughness and the A/F ratio gauge would go from the 2nd green bar to full lean momentarily and then back up to the 3 o'clock position.
You probably have a heat issue that's boiling your fuel which would lean out the mixture. That would explain the fluctuations of the A/F gauge. Carbs are liquid metering devices, not vapour. I would look at insulating/cooling the fuel supply line as well.
 
You probably have a heat issue that's boiling your fuel which would lean out the mixture. That would explain the fluctuations of the A/F gauge. Carbs are liquid metering devices, not vapour. I would look at insulating/cooling the fuel supply line as well.

The fuel supply line is insulated with firesleeve already.
 
The fuel supply line is insulated with firesleeve already.
Ok, but you still need enough fuel flow or cooling to keep the heat from building up underneath it. Insulation helps but it doesn't prevent heat build up, it slows it down the transmission rate. Just exercising my brain over this. Hope you get it figured out.
 
If your gascolator is located on the engine side of the firewall you are probably dealing with vapor lock, especially when using auto fuel. I know of several Sonerais that have had that problem.
 
I installed a new gascolator (on firewall side) lower R/H side (as sitting in cockpit) when I also bought a new Aerovee Aeroinjector carb.. I had heard that vapor lock was an issue with gascolators on these birds. I took action before a problem (like yours perhaps?) presented itself. I fabb'd a removable heat shield (in the form of a wrapping...an overcoat of sorts), made out of surplus firewall fireproofing/heat covering material, that I also installed when I had the engine off to install electric starter system. I also covered main fuel supply line with firesleeve material running from gascolator to Aerovee Aerocarb inlet. I have flown it in very warm temps here in NC summers with high humidity as well as extensive ground runs. No way to be certain of any (one thing) but I have never had a "stumble" during any full range/RPM ground run or flight during (T.off)/cruise/glide in) at idle RPM for landing. My engine has the short stacks, so most of heat that would flow past the gascolator is waste air ducting off and out of cowl from baffles/cylinder cooling fins...hot,.. but NOT 'blazing-hot!' exhaust stack heat. I bought the firewall covering material in a roll from Acft.Spruce. Cut it to shape and glued in down with ultra high-temp rated RTV sealant...also from 'Spruce. It is the same covering the NASCAR guys use to cover the exposed surfaces inside the cabin areas to protect the driver from heat buildup and fire. Not exactly cheap, but pretty easy to cut and attach...works great to insulate & protect. My "heat coat" idea seemed to work GREAT for me. Just my contribution here...not a Sonerai guru or builder, but have wrenched on my bird quite a bit...especially 'firewall-forward', etc.
 

Attachments

  • Gascolator heat shield RH view.jpg
    Gascolator heat shield RH view.jpg
    1.3 MB · Views: 94
  • Gascolator heatshield btm view.jpg
    Gascolator heatshield btm view.jpg
    1.3 MB · Views: 89
All of these heat issues inside the cowling is why I am experimenting with updraft cooling and dumping the hot air directly overboard. I have no issues with vapor lock and the magneto stays cool without blast tubes. I did however, cover my fuel line with fire sleeve and wrapped it in aluminum tape.

All the best,
Chucker
 
The more I think about it the more convinced I am that this was a heat issue. On my airplane with the long exhaust exiting out the bottom of the cowl it is obviously going to be much worse than those running the short stacks. I think I could probably get away with just shielding the carb and feeding it cooler air, but to be safe I will do some more with the fuel line and gascolator. For the gascolator I think I will box around it and run a tube from the baffle to blast cool it. For the fuel line I think I have a piece of larger diameter firesleeve so I can essentially double firesleeve the hose. I think those things will take care of it.

I didn't have a chance to do anything today but will get as much as i can done tomorrow.
 
I installed a new gascolator (on firewall side) lower R/H side (as sitting in cockpit) when I also bought a new Aerovee Aeroinjector carb.. I had heard that vapor lock was an issue with gascolators on these birds. I took action before a problem (like yours perhaps?) presented itself. I fabb'd a removable heat shield (in the form of a wrapping...an overcoat of sorts), made out of surplus firewall fireproofing/heat covering material, that I also installed when I had the engine off to install electric starter system. I also covered main fuel supply line with firesleeve material running from gascolator to Aerovee Aerocarb inlet. I have flown it in very warm temps here in NC summers with high humidity as well as extensive ground runs. No way to be certain of any (one thing) but I have never had a "stumble" during any full range/RPM ground run or flight during (T.off)/cruise/glide in) at idle RPM for landing. My engine has the short stacks, so most of heat that would flow past the gascolator is waste air ducting off and out of cowl from baffles/cylinder cooling fins...hot,.. but NOT 'blazing-hot!' exhaust stack heat. I bought the firewall covering material in a roll from Acft.Spruce. Cut it to shape and glued in down with ultra high-temp rated RTV sealant...also from 'Spruce. It is the same covering the NASCAR guys use to cover the exposed surfaces inside the cabin areas to protect the driver from heat buildup and fire. Not exactly cheap, but pretty easy to cut and attach...works great to insulate & protect. My "heat coat" idea seemed to work GREAT for me. Just my contribution here...not a Sonerai guru or builder, but have wrenched on my bird quite a bit...especially 'firewall-forward', etc.
Does AeroCarb recommend ram air like REVFLOW does. Work wonders on throttle response. REF http://revmasteraviation.com/wp-content/uploads/2010/07/revflowass.jpg
 
Back
Top