LA 40 with fuel problems

I got my Excaliber Stunt finished and test ran the engine today. The problem I am having is the LA 40 witht he remote needle valve will not maintain a positive fuel flow. Soon as I prime it the fuel runs back towards the needle. Is there a fix for this?

I know most will say to go to a standard needle up front and I am willing to do that but what is the best needle assembly to use? I do want to try to fly this plane this weekend and don't anticipate being able to get a replacement needle valve before then so would really like to hear some ideas about how to resolve the prolbem I have with the remote needle.

Thanks,

Did it ever run at all? Sounds as though the tank needs to be elevated some. If the motor will run just a little while I would think it would start drawing fuel and continue to do so. Guys in Ft Worth are doing ok with the remote- it just takes a while to stop running in flight-starts are not a problem.

>Did it ever run at all? Sounds as though the tank needs to
>be elevated some. If the motor will run just a little while
>I would think it would start drawing fuel and continue to do
>so. Guys in Ft Worth are doing ok with the remote- it just
>takes a while to stop running in flight-starts are not a
>problem.

Yes, with some work I can get it to run. The tank is mounted with the centerline approx 1/8 inch above the engine centerline (Brodak 4 oz tank). When I ran it on the engine stand this was a minor problem that I attributed to the tank placement. With the engine on the plane and a full tank I can get it started with a little work. It ran about half a tank out on the ground before it died. I will have to wait until the weekend to get it in the air and see if I can get a full tank through it.

LAST EDITED ON Apr-07-04 AT 08:24 PM (CDT)
 
Do yourself a huge favor and replace the plastic backplate with one for a Tower .40, and install a regular NVA. I favor the "Randy Aero"/ Nelson NVA. Leonard usually has them. At that time, you will need to drill out the holes #21 (.159") ( and drill out the venturi to 9/32" (.281") or so. While you're at it, replace the screws with socket heads (a set for a Magnum will be perfect). The idea is to "set it up" before you fly, so it will not have any questionable issues that will cause grief later. Could save your airplane. Think of it as REALLY cheap insurance. Steve

While the PA needles are nice, and I use them in a couple models, Len has the good ol' standard (front-mount) O.S. needle valve assemblies in stock. Bought a couple sets myself recently. The "clicker" is a nice feature, won't have to bore out your venturi.

Suitable metric cap screws are most easily obtained from a Du-Bro rack stocked by a great many hobby shops. Sizes which are not available from even local specialty fastener houses are stocked.

>While the PA needles are nice, and I use them in a couple
>models, Len has the good ol' standard (front-mount) O.S.
>needle valve assemblies in stock. Bought a couple sets
>myself recently. The "clicker" is a nice feature, won't have
>to bore out your venturi.
>
>Suitable metric cap screws are most easily obtained from a
>Du-Bro rack stocked by a great many hobby shops. Sizes which
>are not available from even local specialty fastener houses
>are stocked.
>
>Dan

Just ordered two of the OS FP NVA's from Leonard this morning. I'm hoping that these will solve this problem.

Thanks,

"The problem I am having is the LA 40 witht he remote needle valve will not maintain a positive fuel flow. Soon as I prime it the fuel runs back towards the needle."
"Just ordered two of the OS FP NVA's from Leonard this
morning. I'm hoping that these will solve this problem. "

Finch,
I had the same experience with a new OS .40FP-S that came with a remote needle valve assembly and was installed on a SIG Banshee. After choking, the fuel would flow back toward the needle. If it was choked a bunch it would start and finally pull fuel to the engine. Also, at the end of a flight the engine would sputter cutting in and out for 8 to 10 laps before finally quitting. I removed the remote assembly and installed a stock OS needle valve assembly at the venturi. Problems solved! No fuel flow back and a clean engine shutdown at flight's end.
DennisV

Henry also has them in stock over at the hobby shop.

I agree with all the above. I change the backplate and the screws, along wiht the needle valve. It doesn't matter if you use an OS, Nelson, or Supertigre unit. Just go ahead and get it moved up front.

Looks like we will be flying at the parking lot - hope to see you there.

Ron King

>Henry also has them in stock over at the hobby shop.
>
>I agree with all the above. I change the backplate and the
>screws, along wiht the needle valve. It doesn't matter if
>you use an OS, Nelson, or Supertigre unit. Just go ahead and
>get it moved up front.
>
>Looks like we will be flying at the parking lot - hope to
>see you there.

Come to think of it I do have a ST NVA that I could try.

I'll be at the cleanup on Saturday but hope to fly some after that. If that's at the parking lot or somewhere else we'll have to wait and see. I'll be bringing a O.S. 15 along for the trip.

L8trz,

>It ran about half a tank out on the ground before it died.

Being a metal tank, if you were not holding the plane with the outboard wing down, or the nose vertical, it will only run a little over a 1/2 tank before the pick up is un covered.
I would still go with a metal backplate and standard NVA just to eliminate any future problems in those areas.
Bill <><

A couple more thoughts. An electric starter would cure the fuel flow issue, I'm certain. Also, I have been using the Bruline air filters on inverted engines, and they really are a big help in starting the engine. With an inverted engine, you choke it, all the fuel drains out on the ground. With the filter, it soaks the filter, and when you flip the prop (or hit the starter button), the fumes out of the filter are just what's needed for an easy start. With the filter, there is ABSOLUTELY no need to flip the airplane upside down. How this would work on a side mount is unknown, but it certainly won't hurt. Steve

Finch,

Do you know a brother-in-law of mine is an expert falconer? If that flitting little finch is annoying you in any way, give us a call.

Acknowledging that you might not get the front-mount NVAs in time, and all you really want to do is fly the new model to see if it is tweaked in some way, Steve's suggestion to use an electric starter is really good. Who cares if in a static condition the fuel runs away from the remote. Grinding away with the starter motor, the tip of one digit over the venturi ought take care of that problem immediately.

If it doesn't and you are using muffler pressure, closing off stinger on muffler while cranking engine will deliver enough fuel to combustion chamber that you will be able to stage your very own impromptu rod test.

While I have never taken the time to ponder the situation, at one point in the highly controversial ARF Flite Streak/20FP deal I was using a remote on one engine and had a similar thing happen. However, it turned out the needle was open big-time and on subsequent starts the problem was much less of a factor. And then I went to old-style NVAs from Len, which sounds to be in your near future.

>Finch,
>
>Do you know a brother-in-law of mine is an expert falconer?
>If that flitting little finch is annoying you in any way,
>give us a call.

Falconry, Now thats freeflight with a whole new meaning.

>Acknowledging that you might not get the front-mount NVAs in
>time, and all you really want to do is fly the new model to
>see if it is tweaked in some way, Steve's suggestion to use
>an electric starter is really good. Who cares if in a static
>condition the fuel runs away from the remote. Grinding away
>with the starter motor, the tip of one digit over the
>venturi ought take care of that problem immediately.

>If it doesn't and you are using muffler pressure, closing
>off stinger on muffler while cranking engine will deliver
>enough fuel to combustion chamber that you will be able to
>stage your very own impromptu rod test.

While I don't currently own an electric starter (haven't really needed one except for a stuborn Fox .35) I have been able to start this engine and the rest of my engines by flipping. If I do fly it this weekend with the existing setup it will be very conservative flying. Using a tounge muffler with no pressure fitting for the tank. I could always add one if needed but doesn't seem to need it at this point.

Thanks,

I've been using a OS remote needle , and I've experienced non of these problems.

PLUS I keep my fingers away from the prop...

What a day. You couldn't have ask for a nicer day to fly. I put the LA 40 in the air and it performed very well. Once started it ran like a champ until the last 6-8 laps, on those laps it cycled between lean and normal while the engine decided if it wanted to quit. Starting it was very easy (starter I don't need no stink'n starter), and the bottom of the tank run was ok also since it let me know that the end was coming and I could quit messing around. I will put a standard needle on it but I found that I could live just fine with the Remote Needle.

Specs on the Excalibur II
OS LA .40 c/l
40+ oz range
4.5 oz Brodak tank
11x4 Zinger prop

Unfortunatly the wing on the Excalibur II isn't quite up to par strength wise so I must uncover strengthen the wing and recover it. Also had some other trim issues to work out but they will have to wait for the wing to get fixed.

Fly'n Circles,