Author Topic: Engine quits at end of tank with no warning (Read 2603 times)

Ken Culbertson · « **on:** May 20, 2018, 11:01:23 AM »

I am running a OSLA46 that has a peculiar habit of just stopping when it runs out of fuel. No sputter, burp speedup, it just quits when it is empty and does not respond to a "Kill Loop". There is less than 1/16 ounce in the tank when I land. It normally runs a nice 4-2 but how it runs has no bearing on how it quits. It also runs 9 min on 4 oz of fuel. Locals are as baffled as I am. I can probably jack with the venturi but I think I have tank issues. Sullivan 6oz clunk with muffler pressure "Out" of the fuel. Any ideas, I miss that "burp" a few laps from quitting that tells me that I am about to land or DON'T do the clover.

FYI - it did the same thing on a 6oz metal tank using muffler pressure "in" the fuel.

After Thought - Could it be the fuel filter?

Ken

Lauri Malila · « **Reply #1 on:** May 20, 2018, 11:29:10 AM »

But that sounds good.
If it’s allways the same, use stopwatch to see when it’ll stop. L

RknRusty · « **Reply #2 on:** May 20, 2018, 11:44:44 AM »

I too had an LA46 on my Cardinal, plumbed just like you describe, and it also just stopped when it ran out of fuel. No warning, it just quit when it was empty and dry inside. I may have a bigger venturi, as my fuel mileage is less than yours, but good for a pattern and a few extra laps.

I thought that was a perfect example of how a stunt run was supposed to be. I take some pride in knowing exactly how many laps it flies before it cuts off. I fill to a mark on my transparent tank and know it'll give me 7 laps after the clover. Or a few more laps if I need a bit of extra fuel on a day when the winds are unpredictable and I might have to wait out a thermal or two.
Rusty

Dave_Trible · « **Reply #3 on:** May 20, 2018, 11:53:01 AM »

At least for contest flying that might be a problem to strive for.....you just pull out enough fuel if need be to go about 7-8 laps after the clover and call it good. Burping and screaming after the pattern for several laps is distracting. Obviously you don’t do extraneous wasted maneuvers after the pattern. If you are not really doing a consistent pattern each flight- training or testing or just playing - then put a stopwatch on it and check your flight time during the flight. The plumbing in your tank seems to be working.

Daveo

Ken Culbertson · « **Reply #4 on:** May 20, 2018, 12:02:35 PM »

Quote from: Dave_Trible on May 20, 2018, 11:53:01 AM

At least for contest flying that might be a problem to strive for.....you just pull out enough fuel if need be to go about 7-8 laps after the clover and call it good. Burping and screaming after the pattern for several laps is distracting. Obviously you don’t do extraneous wasted maneuvers after the pattern.

Dave

So far that is the plan and I do like having a tank that lets me put on as much fuel as I need but I have never had an engine that did absolutely nothing different before quitting so I am probably fixing things that are not broken just to make it do it!

One other "issue" - is 7 1/2" from the fuel pickup to the NV too much before I go and fix another thing that isn't broken?

Ken Culbertson · « **Reply #5 on:** May 20, 2018, 12:13:17 PM »

Quote from: RknRusty on May 20, 2018, 11:44:44 AM

I thought that was a perfect example of how a stunt run was supposed to be.

Maybe I am just finding out how much better engines have gotten in the last 30 years. I thought only the other guy's engine could run perfectly!

Ken

Lauri Malila · « **Reply #6 on:** May 20, 2018, 12:22:25 PM »

One possible cure for your non-existent problem would be a remote needle valve. When there is fuel left only between valve and spraybar, the engine usually goes richer for a couple of seconds before it stops. L

RandySmith · « **Reply #7 on:** May 20, 2018, 12:44:50 PM »

Quote from: Lauri Malila on May 20, 2018, 12:22:25 PM

One possible cure for your non-existent problem would be a remote needle valve. When there is fuel left only between valve and spraybar, the engine usually goes richer for a couple of seconds before it stops. L

If you plumb the tank uniflow, they also will normally go rich right as the fuel runs out, for a couple of seconds, But I agree this s not a problem, just measure fuel and fly out the last bits after you do the pattern, pay close attention and you may see the engine going rich at the end

Randy

Brett Buck · « **Reply #8 on:** May 20, 2018, 04:13:40 PM »

Quote from: Motorman on May 20, 2018, 02:50:21 PM

You can pull out of any maneuver dead stick and land on the wheels if you keep momentum.

But you aren't going to keep momentum at many possible spots it might quit.

Brett

Ken Culbertson · « **Reply #9 on:** May 20, 2018, 05:26:59 PM »

Quote from: Brett Buck on May 20, 2018, 04:13:40 PM

But you aren't going to keep momentum at many possible spots it might quit.

Brett

So true. It takes a lot of wind to be able to save it anywhere but I am not too concerned with it quitting in the pattern. I am guessing that this is just a characteristic of this engine that I need to learn to live with. especially since others seem to have the same experience. I don't know enough about engines to screw around with the venturi or NVA to see if it changes things so I guess it is enough gas to do the pattern + more laps that I want to fly but less than an overrun and keep it high enough to still land where I want to. That is the real problem. I am used timing my landing with a kill loop. Now what I get is a justa loop. Maybe if I use a DT fuse......

Ken

Tim Wescott · « **Reply #10 on:** May 20, 2018, 05:53:36 PM »

Quote from: Lauri Malila on May 20, 2018, 12:22:25 PM

One possible cure for your non-existent problem would be a remote needle valve. When there is fuel left only between valve and spraybar, the engine usually goes richer for a couple of seconds before it stops. L

Oh thank you -- I've been wondering why my plane did that, now I know. And it makes perfect sense why, too (and gives a nice, repeatable warning).

Tim Wescott · « **Reply #11 on:** May 20, 2018, 05:56:26 PM »

Quote from: Ken Culbertson on May 20, 2018, 11:01:23 AM

Sullivan 6oz clunk

With emphasis on the clunk. It's doing it's job and sucking out the last drop of fuel with no muss, fuss, or bother. If the engine runs consistently enough, take Dave Trible's suggestion and enjoy it. I always set up my planes with clunks (even the metal tanks), they all work that way, and I like it.

FLOYD CARTER · « **Reply #12 on:** May 20, 2018, 07:02:56 PM »

I wish I had y our problem! Not sure if it is my OS46LA, but probably is. Mine gives "coughs and wheezes" for several laps. Just when I think it is dead, it comes back for another full run. Not a serious problem, but is embarrassing during a contest! I normally use a hard tank with the uni flo tube just short of the fuel pickup.

Ken Culbertson · « **Reply #13 on:** May 20, 2018, 07:21:24 PM »

Quote from: Tim Wescott on May 20, 2018, 05:56:26 PM

With emphasis on the clunk. It's doing it's job and sucking out the last drop of fuel with no muss, fuss, or bother. If the engine runs consistently enough, take Dave Trible's suggestion and enjoy it. I always set up my planes with clunks (even the metal tanks), they all work that way, and I like it.

My OS35 runs to empty on the same tank but it gives me two "Brepps" when it is ready to be killed. I am going to try the remote needle valve. That is one of them new fangled things I have never used but I guess I gotta learn sometime and it makes sense.

I assume you set the "real" needle to max rich then set the run with the fake one. Am I going to be dragged kicking and screaming into electric?

If I don't come home from flying smelling like a caster bean my wife will be suspicious.

Ken Culbertson · « **Reply #14 on:** May 20, 2018, 07:49:15 PM »

Quote from: FLOYD CARTER on May 20, 2018, 07:02:56 PM

I wish I had y our problem! Not sure if it is my OS46LA, but probably is. Mine gives "coughs and wheezes" for several laps. Just when I think it is dead, it comes back for another full run. Not a serious problem, but is embarrassing during a contest! I normally use a hard tank with the uni flo tube just short of the fuel pickup.

That is my normal metal tank arrangement too. I had a 6oz in the plane but it was just too big. Took 3oz just to keep the pickup in fuel long enough to launch it. Still quit the same way. At least with a Clunk you can do proper trim flights. My OS35s does what yours does when it is cold. If I set the needle just a click below the 4-2 on the ground it would be fine in the air - if it was warmed up. Do the same cold and it does what yours does. At a contest I would always crank it up for about 15 sec if it hadn't been run in the last couple of hours. Friend of mine runs Stalker's and he has to do something similar.

Dan McEntee · « **Reply #15 on:** May 20, 2018, 08:17:59 PM »

Quote from: FLOYD CARTER on May 20, 2018, 07:02:56 PM

I wish I had y our problem! Not sure if it is my OS46LA, but probably is. Mine gives "coughs and wheezes" for several laps. Just when I think it is dead, it comes back for another full run. Not a serious problem, but is embarrassing during a contest! I normally use a hard tank with the uni flo tube just short of the fuel pickup.

This is usually a sign that the back end of the tank needs to be canted outboard of the fuselage so it can pick up better. The rear needle valve works fine. I set up several airplanes for Sean with them when he was younger to help keep his fingers away from the prop while he was learning. What I learned about them was the engine run is the same, but it takes more choking for starting, and having the back end of the tank pitched out is a must for cleaner cut offs. Most guys would kill for a run and shut off as described! You should be keeping better time of your engine runs and be more accurate on how you fill the tank. Then you can have the confidence to just fly the patter, and a quick glance at your stop watch (you do time EVERY engine run, don't you??) tells you where you are in the tank. Practice and repetition will tell you at 4:30 of the engine run, you should be in a certain maneuver. If you are way over that time, don't continue. If you are finished with the pattern, you shouldn't need a warning to be ready for landing, you know it's coming!
Type at you later,
Dan McEntee

Tim Wescott · « **Reply #16 on:** May 20, 2018, 08:47:22 PM »

Quote from: Ken Culbertson on May 20, 2018, 07:21:24 PM

My OS35 runs to empty on the same tank but it gives me two "Brepps" when it is ready to be killed. I am going to try the remote needle valve. That is one of them new fangled things I have never used but I guess I gotta learn sometime and it makes sense. I assume you set the "real" needle to max rich then set the run with the fake one. Am I going to be dragged kicking and screaming into electric? If I don't come home from flying smelling like a caster bean my wife will be suspicious.

You use a spraybar that does not have any metering, and meter the fuel with the remote. If you haven't drilled the case out, and you can find one, then you can use a stock spraybar & needle for a remote setup. I'm not sure what to suggest if you've drilled it out for an ST needle.

Howard Rush · « **Reply #17 on:** May 21, 2018, 01:15:07 PM »

Quote from: Brett Buck on May 20, 2018, 04:13:40 PM

But you aren't going to keep momentum at many possible spots it might quit.

That's one of the differences I noticed between combat and stunt planes. Combat planes have enough kinetic energy to get out of any maneuver when the engine quits.

Dan McEntee · « **Reply #18 on:** May 21, 2018, 05:45:29 PM »

Quote from: Motorman on May 21, 2018, 01:19:21 PM

Like what?

Entering the intersection of the clover after the last loop, either pull up for the wing over, the intersection of the hour glass after the first turn, the last turn of the outside square portion of the square eight all come to mind.
Type at you later,
Dan McEntee

Ken Culbertson · « **Reply #19 on:** May 21, 2018, 06:14:40 PM »

Quote from: Dan McEntee on May 21, 2018, 05:45:29 PM

Entering the intersection of the clover after the last loop, either pull up for the wing over, the intersection of the hour glass after the first turn, the last turn of the outside square portion of the square eight all come to mind.
Type at you later,
Dan McEntee

My preference is to not have it quit at all! And, yes there are more!

Steve Helmick · « **Reply #20 on:** May 22, 2018, 08:07:47 PM »

Ken, when a new plane takes a lot of laps of burping before shutdown, the standard fix is to tilt the back of the tank outward, OR move the LO's forward. In the case of no warning at all, the reverse should also work. The question then is, are your LO's in the right place? It might indicate that they're too far forward...which isn't terribly likely, but you might also reverse the tilt of the tank by 1/16" > 1/8" at the front. Should work, it says right here in the fine print.

If you were using a metal uniflow tank, you can increase the distance between the uniflow outlet and the fuel pickup. That is another way to go, and would also allow you to use the shutoff loop trickery. If you stick with a clunk tank, you will NOT be able to use a "shutoff loop".

I do have some suspicions about the effects of small vs. large clunks, or tapered clunks. And those sintered bronze filter clunks...I don't see how those could possibly feed constant up to the last drop, since they would be pulling fumes from the inboard side and liquid from the outboard side. So the clunk type might be a useful adjustment, but I've not done that. Maybe somebody else has?

Steve

Ken Culbertson · « **Reply #21 on:** May 22, 2018, 10:00:42 PM »

Quote from: Steve Helmick on May 22, 2018, 08:07:47 PM

Ken, when a new plane takes a lot of laps of burping before shutdown, the standard fix is to tilt the back of the tank outward, OR move the LO's forward. In the case of no warning at all, the reverse should also work. The question then is, are your LO's in the right place? It might indicate that they're too far forward...which isn't terribly likely, but you might also reverse the tilt of the tank by 1/16" > 1/8" at the front. Should work, it says right here in the fine print.

If you were using a metal uniflow tank, you can increase the distance between the uniflow outlet and the fuel pickup. That is another way to go, and would also allow you to use the shutoff loop trickery. If you stick with a clunk tank, you will NOT be able to use a "shutoff loop".

I do have some suspicions about the effects of small vs. large clunks, or tapered clunks. And those sintered bronze filter clunks...I don't see how those could possibly feed constant up to the last drop, since they would be pulling fumes from the inboard side and liquid from the outboard side. So the clunk type might be a useful adjustment, but I've not done that. Maybe somebody else has? Steve

I had a metal uniflow and considered moving the uniflow forward like you suggested but I pulled it because it took 3 oz in the 6oz tank to get it off the ground for trimming. Replaced with 6oz Sullivan clunk. You are right about the loop with a clunk, I forgot that one. Looks like my only out is to get a trained cockroach to hide in the engine cavity and jump into the venturi when I signal or, measure fuel and learn to land from anywhere. Probably going to run out the tank at 5' and just land when it quits. Plane will land hot with no bounce.

Ken Culbertson · « **Reply #22 on:** May 24, 2018, 12:44:43 PM »

Thanks for all the help. I have learned a lot from this thread. The temperature was up yesterday so I switched from 5% to 10% and ran it a tad richer and it now gives me a sputter 2 laps before quitting. The list of things I do not know about engines just keeps getting longer!

Ken