ETLB Squawk Forums — Archive

Well, although this is not a flying story.....it is leading up to one!?!  I did my first taxi with the HiMax on Monday.  I used my cell phone for a video, and held it with one hand while trying to keep the elevator down when going downwind, and up while going upwind.  And a little down aileron on the upwind side.  Although the video does not last much longer than the downwind leg.  I was trying to record the moment, as well as the cht and egt temps while doing the taxi.  

I managed to get the tail up several times, although for only 5 sec. or so before putting it back down.  Only had one OPPS, when I almost left the runway, but got it back just in time.  The wind was picking up about that time, so, I will let that and inattention take the blame.  

This was pretty exciting for me!  Finally getting in and running it back and forth.  Skyview was not busy, so I was able to taxi both ways on the main runway.  Did not see another plane.  In all, I put in right at an hour on the Hobbs with taxi and messing around.  

Following is the link to the video.  Turn the sound down and if you get sea sick with the bouncing of the camera....well, you have been warned!  LOL!  https://www.youtube.com/watch?v=wEUvmwsXaKg&feature=youtu.be

Dennis

Looking good. I dont think you are too tight on space in that area but you may also try to feel how easy to turn the max with stick slightly forward.  That also helps to build your confidence learning that its not so easy to flip it over on its nose. The harder you pull the stick, more difficult to turn. Most common problem of tripacer flyers sitting in a tailwheeler that they are too scared of let the stick forward because it may set on its nose. Not that easy...
The less you are loading the tail with the stick by pulling back the more easy to gain speed to have efficient rudder in the air. Dont pump it back and forth. You may also see if you apply throttle how the stick moves by itself.
Actually you need to push that forward quite drastically to have your tail lifted while standing.

If you happen to rotate unintentionally and fly in a feet or two above the ground, just release the throttle slowly back, dont just pull it back fast.  This way you can avoid bouncing and slowly reduce speed. Just keep it straight no fast movements.

Hi Peter,

Great advise about turning with the stick some forward.  I tried that today, and it worked much easier!  Had not thought of that.  I got in about 30 minutes this morning....then she quit.  Sounded like a gradual slow down in rpm's until it died.  Turned out the left tank was empty, and the right tank only had 1/4.  Gauges were reading 1/4th, and 1/2.  Bob has been helping me most of today trying to get it going again.  Went down many false paths trying to figure it all out.  Before checking the fuel!!  Geezzzz.  In the process, I checked the screen in the gascolater...clean.  Then, I found rubber pieces in the can I was catching the gas in.  Eventually took all the cowling off to see what I could find.  Turned out to be a rubber wrap on two hoses, to protect them from each other that were doing their job and dropped pieces on the motor mount.  Then when I spilled the gas taking the gascolater off, it washed into the can.  

After refueling, I got it started, but it only ran about 600 rpm, and could barely keep it going.  Shut off.  This is when I took the cowling off.  Bob told me how to prime the pump, then fill the float bowls on the carbs and try again.  It started, and after running at 600 rpm for 20 to 30 sec, it smoothed out and ran normally.  I did not try a test run as the wind had come up.  So, I shut it off and put the cowling back on.  About 5 interruptions and 45 min later I started it again to make sure it was still going to run.  It did the same thing.  Ran at 600 rpm and then finally smoothed out and ran normally.  With the exception that I was running at 4000, 5600 rpm and other speeds to recheck temps.....and once or twice, I noticed it gained an lost about 200 rpm.  

It acts like it is losing it's prime.  So, now I am wondering if:  a.)  The pump has a problem.  Bob and I visited about that today.  b.)  If there is a tiny hole in the suction line from the motor that runs the pump.  The two lines that were rubbing were the fuel line to the right carb, and the vacuum line to the motor.  c.)  Long shot which I did not have time to check out, but I wondered it the choke may not be working properly.  

I am convinced that it is not electrical, but fuel supply.  Will probably order parts to rebuild the pump tonight...and hose.  How many feet of fuel line are there all together?  All thoughts will be appreciated.  

The half hour that I did run, I got the tail up several times for pretty long distances.  It is getting a little better.....by degrees

Dennis

Dennis,
You cant avoid to do some learning curves, everybody had that This is act of God for you to know your plane better inside out, since you are the guy who needs to maintain it. The more happens and you get over without having too much frustration, the more we learn and keep our flights safe.

Bob is a super master of mechanic, but there are some things which is outta his authority. I dont know , my guess that your plane grounded too long. Looking the problem, I would replace all hoses if you have rubber particles in there. Not that difficult.

Starting a two stroker is not always easy once if you flood the engine after suspecting that it has no fuel. But once you settle on the methode its ok. Also bubbles in the fuel line makes it difficult until you get that out. You dont know whats going on and get "digital"  (on-off) on choke and its easy to keep or escalate the problem more than it exist by itself.

I have the wing tank in my CUB himax, but they joined only in a T junction. I am also thinking about having a small (1/4 gal) joining tank) to prevent air bubbles in the hose line if one goes empty or emptying faster than the other -which is always the case. This may come due to different pressure in the fuel tanks so its important that as fuel goes , air comes in at the fuel cup.
In my high wing aircrafts both on the ICP Bingo (Savannah) , the former KitFox and the  CUB Himax has fuel cups which have a little pipe in the middle which is forwarded to get ram air from the direction, thats creating a bit of pressure over the fuel and creating constant flow without letting bubble in the pipeline (as long as you let the tank full empty by mistake).  In my Bingo the fuel cap has a little plastic tube which goes under the wing where more pressure than above. Thats a better solution, since I had once that bees went into the little airtube and clogged it with clay, similarly as they can clog the pitot tube. Than you have no air coming in the fuel tank, so thats an other problem.

Once I forgot a fuel cap in the wing and flying sucked half of the fuel on a circuit. If you have a simple hole on it it may be at vacum, no pressure, and that explains why one emptying much faster than the other.

Before you rebuilt your pump change hose and make sure you have created that little extra pressure by ram air at the top of your wingtank plugs. Change filter.
Those fuel pumps very seldom to fail.

(Here in Eastern Europe we had two stroker cars like Trabant, which had a fuel tank in the engine compartment. There was a 1mm hole on the top of the cup, and most common problem that when they refuelled it, they always had a piece of cloths in the engine compartment to wipe out the dropped fuel and mixture, this cloth got dirty fast with the sticky mixture of oil, gas and dirt and 4-5 refuel, clean the cup by the dirty cloth clogged the 1mm hole at the top. Very common problem that within 1-2 miles off from the petrol station the Trabi stopped , the guy got out , opened the engine compartment, than the vacum got sorted out , sit in and again stopped in about 2 minutes. And this went on until they got to a car mechanic who made his hocus-pocus with his toothpick asked for 20 dollars for the "repair" and was sorted out.....)

If I understand you correctly, everything worked well until you ran out of gas on the tank in use.

If that is correct, then I see no reason to think that the fuel pump is bad. I am not sure about the fuel pump you have so I will not try to advise on how to clean/repair it. I highly suspect that it is surprisingly simple.

Your plane is on the ground so you have more trouble shooting options.

Wrap some tape around the spot where you think the vacuum hose from the engine might be worn and see if there is a problem there. The equivalent hose on my plane is worn through the first (outer) layer of rubber and the pump works fine. If you wrap the hose with Gorilla Tape and the symptoms persist, there was no hole in the hose.

A mechanic on site is much more likely to be accurate than is a mechanic on line, but I would think that running out of gas should not have made your fuel pump go bad.

Well Peter and Bert, you and my wife think alike......while I was busy being frustrated, she was busy telling me that it happened in the ideal place!!  As to the venting of the fuel caps, they are clear, and although they do not point forward, they do point to the side rather than the rear.  I am in agreement that this is all related to running out of fuel.  I don't think the fuel pump is damaged by running out of fuel.  I thought the possibility was of sucking in a glob of oil/gas that had dried in the bottom of the tank as it sat.  And, the tank would have to of emptied for this to happen.  But, I suppose if it was small enough to go through the fuel line, then it would probably have settled into the bottom of the gascolator, or stuck to the screen of the same.  Should I add a filter in addition to the gascolator?  If so, what type and where would I get it?  

The rubber parts were not in the fuel system.  They originated from a rubber wrap on the outside of the fuel lines that was to protect them from each other.  They were eventually washed into the can I was catching the gas in.....but again, not in the fuel system.  The next time I go to taxi, I will try to do a better job of priming before I try to start.  This running at 600 rpm did not happen before I ran out of gas.  It would catch, play with the throttle a little, and then come up to speed.  

The fuel lines look and feel solid.  They are the green semi-translucent variety.  I will try putting tape on the vacuum line and see if that makes a difference.  There is no fuel leaking, so I am sure there is not a hole in the fuel line.  I am hoping this is all as simple as running more fuel through it to purge the system.  Although, I did run it for 3 or 4 minutes after I got it going right, and it was running smooth.  

And, as mentioned, it was a good learning process.  I now know how to remove 50 small screws in the cowling without losing any!  LOL!  And, I had a good look inside the engine compartment.  Learned how to prime the Mikuni dual carb vacuum pump.  And learned how to fill the carb bowls.  And, with everyone's help, I will continue to learn......only I hope not under duress!!  

Thanks,

Dennis  

Hi Dennis;
Just a quick note, the vent tubes in the fuel tank caps have got to be pointing to the front. If they point to the rear you can cause a negative pressure in the tank and might cause fuel flow to slow down or stop in flight. I don't know that for fact, but don't want to try and find out either, LOL. Probably not your present problem possibly, but surely a safety item. When you screw the caps on, make sure the vents point forward and are secure so they don't rotate from that position.
Bob

Well, I have an update after further inspection.  I went to the hanger yesterday, and noticed a "strong" smell of gas.  It turns out that the fuel hose from the left tank was leaking at the barbed end ahead of the quick connect.  I probably lost around 1.5 gallons into the cabin, along the underside of the plane etc.  Nothing got beyond the cabin or into the fuse.  Luckily, my bag with wheel blocks etc was in a position behind the seat to soak up much of the fuel.  I talked to Matt at Power Fin today, and he suggested as TTT that I put a clamp of some sort there.  The plastic Herbie clamp (alligator clamp?) seems to be the best, as it does not do as much damage to the hose.  Also, Matt suggested putting a large shrink tube at the end of the hose, which will protect if further from sharp edges.  I think I have room to cut off about an inch of hose, and then will clamp everything.  My lovely wife helped me use two rolls of paper towels trying to mop up the mess.  Everything looks fine, both wood and fabric.  

Next, after discussions with Bob, I disassembled the choke splitter and as he suspected, it is broken......I am stronger than I thought.  So, parts are on order.  And, I am sure that is why I was having difficulty with starting.  

Matt has also suggested installing an inline fuel filter.  He did not mention two, so I think TTT means one on each line before the TEE?  Then, an additional shut off after each filter?  Anyway, a picture is worth a thousand words.  Thanks TTT.  My thought was to put the filter just before the gascolator.  I think they are plastic, so I don't see shatter as an issue unless they get banged pretty good for some reason.  

The last issue is my max RPM is only 5600.  Matt thinks it is probably a size too rich on the main jet.  Before I go to that trouble, I will check the throw on the slides in the carbs.  There is a screw in the slot of the throttle leaver that acts as a stop.  I seem to recall early on that someone tried to remove that screw thinking that it fell out of somewhere.  If it was put back in a different spot, then that could also be a reason for the low RPM.  Also, since the plugs were a light tan, I did not think it was burning rich.

I have looked at the electric fuel pumps.  Have not researched the topic, but, as I was priming with the prop, I think it was around 100 when I started considering this  Ok, not that many!  Do you have an electric pump on yours TTT?  What pressure does it run, and what happens if it quits?  Or, is it a backup to gravity?  

Yes, I am having trouble with the site too.  Usually if I click a second time, it will go.  

Thanks,

Dennis

I put about 1.5 hours on the engine running up and down the runway.  Yes, it ran perfectly, other than the RPM issue.  Very smooth with no hesitation at all and went right up to 5600 RPM.  I gave it several minutes at max RPMs, but it did not increase beyond that.  Several people from the local EAA also have suggested the altitude and jetting as a possibility.  As much as I hate to tackle that project, it may be part of my future  As I said.....I am learning.......

Dennis

Hey Dennis
Full throttle static RPM at 1M5 was 5900 to 6000 RPM. In the air, level flight rpm was 6300 and 74 MPH. These numbers will probably change because of your altitude. I don't know what they will be. Yes you will probably have to lower the main jet size about one size. But right now, I would concentrate on getting your tail wheel endorsement. The engine is running good and not fowling plugs. Go taxie it and learn how to handle it on the ground. Later when you are ready to fly it, then change the jets. You will need the jets you take out for cold weather flying, so don't loose them.
Bob

Hi Bob,

Thanks for the reminder on the RPM's.  I tried to find your email with that info, but, it is now in the ether.  I am not off (RPMs) as far as I thought.  I have the jets you included, which should give me the one size I need.  In my enthusiasm, I also had bought other jets in case the mechanic that checked it out needed more that what I had...... so, I should be good up to 15,000'.  LOL!  

The Remos has a broken spinner (no, I did not), so they have had it grounded for an extended period of time.  They can't get a new one soon, and have been waiting for the sign off from Germany to fly without it...and the FAA, and the insurance company....etc. etc.  So, after almost three months of not flying, I have put in two hours on the Citrabria tail dragger.  The first day was great.  No wind, almost perfect three point landing.  The second day was all landings in a 7 mph crosswind.  I could land ok, but my instructor was wanting me to fly the length of the runway on one wheel......my balance and coordination are apparently not what they used to be!  So, I have been practicing the wheel hop, and seem to be getting very good at it!  LOL!  

Thanks for the help,

Dennis

Hi TTT,

Thanks again for the info.  I have watched the YouTube videos with the Mikuni carb and feel like an expert!  LOL!  These have the access plug at the bottom of the float bowl, so, if memory serves me right, I think I can just rotate them and change without removing the carb.  I am feeling a little better about sync the carbs as well after checking the slides.  Bob has given me the method, but, it's always a question mark until I actually start the process.  

I appreciate your comments, even though I only partially agree with the long trip being a contributor to my ignorance  I do agree that it did have an effect however, and I think the first example was the fuel gauges.  Dry tanks, 1300 miles, and sitting over the winter in the trailer.  I drained the one tank, and sure enough....it still registers a quarter tank.  So, another project is to readjust them.  It sounds easy enough, but if not, Bob will get another list of questions!  LOL!  He is being very patient with me, as are all of you.  And, of course, the EAA guy helping me at the airfield asked the obvious......Did you check the tanks with a stick to make sure?  I won't make that mistake again!!  

Dennis

Dennis, you can always delete the second comment by clicking delete on the right upper corner of that comment.

Thats one thing,
The other is that like Bob said, fly this thing first, than make mods. You have lotsa clear spaces in WY so dont worry too much about it. I know the feeling how it is, even Japanese try to improve on melons doing them squaredd but that particular plane most probably need  white gloves and silk scarf to fly - as I know Bobs work...

I don't know why, but had never noticed the delete option!  Thanks.  I kept clicking trying to get something to happen, and when it did.....it was twice.  Site is working great now!  

I received the parts last night to repair the choke splitter.  I was planning on a trip to Cheyenne to repair it today, but the weather is not cooperating on that front.  

LOL, you are surely right about the gloves and scarf!  When I read about a few hundred feet for take-off...even if that is exaggerated, then I can reasonably assume that 3-400 RPM will have little effect on the same with a 3,900' runway?  A serious question, as I have no experience yet and don't know the plane, or my own limits yet.  When doing the taxi runs, it seems to have plenty of power, and although I did not TTW it for more than a few seconds, I don't think it would have taken very long to be airborne.  The air speed indicator was starting to register, so I backed it off.  It accelerated very quickly however.  

The field I am flying off is grass, but, underlying gravel.  Small stuff mostly.  I know I have marks that were not on the prop when I started.  This has a fiberglass prop with a tape protector on the edge.  Is there anything I can of should do to provide more protection.  When I get it home, it will be a grass field with dirt underneath.  That will be better I hope.  

Thanks for the encouragement.  

3900 ft runway ?  
My runway at 2500 AMSL is barely 600 ft with a 40 horse engine. And with the others 4a084 I have I fly off from a 1300 ft runway. That thing you have now will rotate in 250 ft with no headwind.

Use the 3M protector tape, available from Aicraft spruce but thats expensive 10 bucks for a roll, if you need to replace, - but if you go to a local garage who makes car foils and ask for a few waste srtipes of 3M stoneguard  film and you cut it at home its exactly the same.

But no worry about soil since its a bigger problem for pushers like trikes where the wheel gets up the stone and throw it into the prop.
All you need to do is to make sure that the prop is always spinning at the front of you. And if that happens to be in one direction where you actually intend to go you are doing a good job  

Yes, 3900' in length, and 5838' elevation.  One guy is flying some sort of twin off of this runway.  The gravel is naturally occurring.  Thanks for the info on the 3M tape.  

Dennis