AeroInjector questions

[John B]

I posted this in my other thread, but thought that maybe the title would keep some from even reading. So anyway, Ive been trying to get my Sonerai running with a cv40 but am to the point where I just need to get it back in the air. In that vein I ordered an AerInjector this morning. Hopefully it won't take too long to get here. In the meantime I am going to get the airframe/engine as ready to accept it as possible. so I have a few questions.

1. My previous carb required a fuel pump and the airplane currently has dual electric fuel pumps running through a spring type mechanical fuel pressure regulator. I read in the AeroInjector manual that my setup can be used, but from other AeroInjector users, would I be better off switching to gravity feed?

2. How sensitive is the mixture control system? My last carb had no mixture control so I'm starting from scratch here. I have a high quality locking push-pull cable but will I need a vernier type cable?

3. Does the mixture control have a spring to hold it open (rich), or does it rely on a stiff wire bowden cable to go to the rich position (ie: Don't use a flexible stranded cable.)?

4. Since fuel can run from the carb if the mixture control is not idle cutoff, I am trying to decide my preferred mounting angle. I could mount it angled down (up-draft) so that any fuel that runs out of the carb runs out of the throat, but then any fuel that runs out it is inside the cowl (possible fire hazard). If I put an elbow on and mount it horizontal (side-draft) then any fuel that runs through the carb will sit in the elbow behind the carb possibly creating a flooding potential. I'd like to hear how others have theirs mounted and their experiences.

Thanks John Brannen

 

[mhflyit]

1. not knowing your setup - my Sonerai is gravity fed and the engine runs to the last drop of fuel
2. I lean one inch or so when taxing - rpms go up
3. no spring - flexible 'standard' mixture cable - push/pull
4. the fuel line should run slightly uphill to the carb

 

[cosmic]

I posted this in my other thread, but thought that maybe the title would keep some from even reading. So anyway, Ive been trying to get my Sonerai running with a cv40 but am to the point where I just need to get it back in the air. In that vein I ordered an AerInjector this morning. Hopefully it won't take too long to get here. In the meantime I am going to get the airframe/engine as ready to accept it as possible. so I have a few questions.

1. My previous carb required a fuel pump and the airplane currently has dual electric fuel pumps running through a spring type mechanical fuel pressure regulator. I read in the AeroInjector manual that my setup can be used, but from other AeroInjector users, would I be better off switching to gravity feed?

2. How sensitive is the mixture control system? My last carb had no mixture control so I'm starting from scratch here. I have a high quality locking push-pull cable but will I need a vernier type cable?

3. Does the mixture control have a spring to hold it open (rich), or does it rely on a stiff wire bowden cable to go to the rich position (ie: Don't use a flexible stranded cable.)?

4. Since fuel can run from the carb if the mixture control is not idle cutoff, I am trying to decide my preferred mounting angle. I could mount it angled down (up-draft) so that any fuel that runs out of the carb runs out of the throat, but then any fuel that runs out it is inside the cowl (possible fire hazard). If I put an elbow on and mount it horizontal (side-draft) then any fuel that runs through the carb will sit in the elbow behind the carb possibly creating a flooding potential. I'd like to hear how others have theirs mounted and their experiences.

Thanks John Brannen

I have been messing with an AeroInjector on my Sonerai 1 with a Jabiru 3300 for a couple of months and have a few observations in addition to what mhflyit has already posted.

1. I started with the standard Jabiru arrangement of a series connected Facet cube and Jabiru mechanical pump with 3+ psi fuel pressure. After a lot of fiddling around I could not get it running how I wanted so I added a spring type fuel regulator to get 2 psi and it was much better. I then decided to switch to gravity feed and removed the mechanical pump and regulator. It seems to run fine so I will stick with that and have a simpler and lower weight system. The electric Facet is there as a backup if needed but I have a K&N 2 psi pump that will be installed to replace the 3 psi Facet. Could have saved myself some time and effort if I had just believed what the instructions said.

2. My mixture control is not sensitive. Have thought about a vernier control but not sure it is worth the trouble. I lean about 1 inch when taxiing the same as mhfylit.

3. Would recommmend stiff (solid) wires to control both mixture and throttle. Particularly the throttle because on my Aeroinjector when the mixture screw is adjusted the force required to change throttle settings also changes. Closing the throttle pushes the cable and multi-strand cable was not up to the task. Sometimes it decided to bend rather than push.

4. My Aeroinjector is mounted as a side draft at the rear of the Jabiru engine with the fuel inlet at the bottom. The cut-off when the mixture knob is pulled out is very positive and completely stops fuel flow. Have had no problem with flooding and the engine starts easily.

 

[John B]

Thanks. You hit on what I was getting at regarding cable type. I much prefer return springs and using stranded flexible cable for much smoother operation, but based on your recommendation I'll use solid wire bowden cable. I may still stick with the pumps as they would be able to push/pull out any air in either vent or fuel supply lines. I can regulate down to 1/2 psi if necessary, but it seems the AeroInjector is ok up to about 2 psi. It was set up and checked at 1-1/2 psi with the previous carb so I'll leave it there. On my application if I lose electrical I lose the engine anyway because I have battery powered electronic ignition. I think I will also do a direct side draft because I guess I'd rather have errant fuel in the elbow rather than the cowl. Thanks for the help. Ive seen the AeroInjector up close and it appears well made but I had a horrible experience with the POSa which has left a door taste in my mouth. I sure hope the AeroInjector works better than that POSa I had did.

 

[Bil4381]

Hey John Good Questions.
1. I kept the facet 1-4 psi pump I have because I needed a bit of pressure to get above 2850 rpm. Below 2000 rpm I turn the pump off. Wirth the pump on , I get 3300 rpm using the Jabiru hoop-pine prop. 3300 rpm gives me 180 mph to 200 moh depneding on day and altitude. I'm thinking of switching to a carter inline pump. Fpr one thing the facet pumps fail after a year or two. I've used 4 or 5.
2. I have a cable with a red knob much like a choke cable. I'm not thinking too much about mixture control because Aeroinjector set of the jet and tapered rod just as I asked them too. Basically I run full rich all the time.
3. No the mixture control has no spring. Never heard of a cable breaking, But my throttle does have a beefy spring pulling to full throttle. If the throttle failed, in anyway the spring would give you whatever power was possible. At 3300CC you don't need much throttle to climb and fly. That's why I went to the J3300 engine, power to spare.
4. I mounted the aeroinjector horizontally right aft of the intake manifold. In order to get 3300 rpm needed a straight run from the air filter though the injector to the engine. I made a SS air intake box with air scoop. It houses the K&N filter. The scoop is at 12 o'clock.
4b. So I use a rubber coupling between the filter and aeroinjector. I made a 1/4" hole at 6 0'clock with a 1/4" copper tube to drain any possible fuel in the coupling, to overboard.
John these are the things I;ve done becauise what I tried before didn't work. The braided wire throttle cable I'm now using tends to break strands gradually. Now there I'm thinking of going to a cable with a tube inside a sleeve at each end. Might have to be custom made. I think Spruce offer that.

I posted this in my other thread, but thought that maybe the title would keep some from even reading. So anyway, Ive been trying to get my Sonerai running with a cv40 but am to the point where I just need to get it back in the air. In that vein I ordered an AerInjector this morning. Hopefully it won't take too long to get here. In the meantime I am going to get the airframe/engine as ready to accept it as possible. so I have a few questions.

1. My previous carb required a fuel pump and the airplane currently has dual electric fuel pumps running through a spring type mechanical fuel pressure regulator. I read in the AeroInjector manual that my setup can be used, but from other AeroInjector users, would I be better off switching to gravity feed?

2. How sensitive is the mixture control system? My last carb had no mixture control so I'm starting from scratch here. I have a high quality locking push-pull cable but will I need a vernier type cable?

3. Does the mixture control have a spring to hold it open (rich), or does it rely on a stiff wire bowden cable to go to the rich position (ie: Don't use a flexible stranded cable.)?

4. Since fuel can run from the carb if the mixture control is not idle cutoff, I am trying to decide my preferred mounting angle. I could mount it angled down (up-draft) so that any fuel that runs out of the carb runs out of the throat, but then any fuel that runs out it is inside the cowl (possible fire hazard). If I put an elbow on and mount it horizontal (side-draft) then any fuel that runs through the carb will sit in the elbow behind the carb possibly creating a flooding potential. I'd like to hear how others have theirs mounted and their experiences.

Thanks John Brannen

 

[John B]

So the Aerocarb/AeroInjector finally arrived yesterday. I got it mounted, plumbed and everything relatively easily. I retained my dual electric fuel pumps with pressure regulator set to 1.5 psi. It started right up but was a bit rich. Just a short amount of tuning and it is idling at 750 rpm and can get 3200 rpm static. Smooth throttle advancement works well. mashing the throttle forward results in a little stumble but the engine doesn't quit and catches up. Looks like I'm a go. I hauled the airplane to the airport and got the wings on. Have to do a few things and then she is ready to fly again.

 

[Bil4381]

Congrats. That's what I did and it's a huge success. I would resist the temptation to fiddle. Mine came from the factory spot on.
Not sure which engine you have. Mine is a J3300. In fast cruise above 2850 rpm, it wants that pump on. With it on I get 3300 rpm and somewhere between 180-200. Covers ground very quickly.

So the Aerocarb/AeroInjector finally arrived yesterday. I got it mounted, plumbed and everything relatively easily. I retained my dual electric fuel pumps with pressure regulator set to 1.5 psi. It started right up but was a bit rich. Just a short amount of tuning and it is idling at 750 rpm and can get 3200 rpm static. Smooth throttle advancement works well. mashing the throttle forward results in a little stumble but the engine doesn't quit and catches up. Looks like I'm a go. I hauled the airplane to the airport and got the wings on. Have to do a few things and then she is ready to fly again.

 

[103]

So the Aerocarb/AeroInjector finally arrived yesterday. I got it mounted, plumbed and everything relatively easily. I retained my dual electric fuel pumps with pressure regulator set to 1.5 psi. It started right up but was a bit rich. Just a short amount of tuning and it is idling at 750 rpm and can get 3200 rpm static. Smooth throttle advancement works well. mashing the throttle forward results in a little stumble but the engine doesn't quit and catches up. Looks like I'm a go. I hauled the airplane to the airport and got the wings on. Have to do a few things and then she is ready to fly again.

The slide carbs are great I have the Revflow. I had a quick jam stumble traced the problem to the fact that I washed and oiled the K&N at annual. I believe prior to that it was never oiled. If became progressively more of a filter in the 10 hours since annual.
In my root cause investigation I removed the filter in favor of straight ram air. Re tuned everything and wow the engine runs great! Zero Stumble pushing it in as fast as is reasonable... 3300 on climb vs 3150, Runs cooler not Max 360 CHT on extended climb mid 200's cruise fuel cooled burning 3.2-3.4gph vs under 3 at cruise. Climb is not only limited by oil temp CHT are never an issue Oil only breaches 200 by about 3000ft AGL on a 95f day. Consider eliminating air restrictions and test on the ground for a difference.

Install a bigger free flowing filter or run naked and assume you will need to change pistons and cylinders at 600 hours vs 800 @$160 a set a reasonable trade off.

 

[glgreen232]

It's been over 10 years since I messed with my Aerocarb. But when I was adjusting it and wanted to make it a little richer and backed off the needle then put the locking set screw back in it would turn the needle back in. So you have to watch that the needle doesn't turn when tightening the lock screw.

 

[shocktrooper]

It's been over 10 years since I messed with my Aerocarb. But when I was adjusting it and wanted to make it a little richer and backed off the needle then put the locking set screw back in it would turn the needle back in. So you have to watch that the needle doesn't turn when tightening the lock screw.

I noted this same issue when I first purchased and started tuning my now 4 years old at this time but brand new back then, AerVee Aeroinjector. So to set up a parameter and basis to offset the movement issue...I took a Sharpie and made an index tic mark at 12 o'clock on the metering needle screw (the face-side that touches the lock down set screw)...then torqued down the lock screw...then pulled lock screw out and noted how much movement took place as the two came into contact while being tightened down. It wasn't much (and it doesn't take much to change the mix either!)...but after several cycles of 'checking'.. it was pretty consistent. Then I knew 'how-much- offset' I needed to hit my final torqued down setting to be consistent with the desired mix setting. Just my 2 cents here. This technique worked for (me).

 

[eschrom]

If you have a lathe you can turn a nipple onto the end of the locking screw, with a diameter small enough to go into the hex socket of the needle carrier and of sufficient length to reach bottom. Then when the locking screw is tightened against the carrier the contact is down inside the socket on such a small radius that no turning torque is transmitted. I did this years ago and the carrier hasn't budged since. Actually, the Aerocarb's stock locking screw is too short for this. Go to the hardware store and get a 3/8-16 x 3/4" set screw.