What am I doing wrong???

[Matt Colan]

On my Ares, which flies very well I might add has a 3/4 inch extension shaft and every single time I go to start the engine, it backfires and  the prop comes loose.  Here is what I do for a starting routine on the Ares.

I fuel it up with 10% Sig champion fuel.  After I fill it up I flip the plane over, since I cna't prime the engine upright.  What I do is I fill the venturi up with fuel until it almost reaches the top.  I flip the prop over a few times so that fuel goes into the motor.  Then I put the battery on.  I turn the prop over by hand once and flip it over to start the motor with a chicken stick.  Usually the first flip and sometimes while turning the prop over, the prop comes loose.  Now I have to tighten the prop.  After I tighten the prop and flip the prop backwards it starts right up.

Now after every flight I tighten the prop and it still comes loose.  I have sandpaper behind the prop and I checked every surface and there are serrations on every surface.  Any idea on what I'm doing wrong?  I know in contests you have 3 attempts to make 2 official flights so this is not good.  Also Brodak is a week away and I got to fix this.

Thanks

[Matt Colan]

I assume this is a wood prop?  Sounds like it isn't as tight as one would hope.  Also three or four drops is usually enough prime, three or four flips after the prime, then connect the glow  plug. Over prime will cause backfires, and that causes a "loose" prop to come free, as you well know....  I had the same trouble with my 59 and 58 Ares. Couldn't get to the venturi either, so did as above. One had a Brodak .40 (which flood easily, so prime lightly) and the other had an OS .35-S.

I'm using a 10-6 powerpoint wood prop.  I'm running an OS .35S in my Ares.  I did put very little prime in it when I first started flying it, and it wouldn't start, I put more fuel in and it finally started to start with a greater frequency of within 30 seconds.  Now the prop comes loose.  I hope I can fly again before going to Brodak and see what putting less fuel in the venturi does.

[Will Davis]

Matt,

Your trouble may be in the shaft extension, put a piece of thin sandpaper on it too, all of the things between the drive washer, (shaft ext,spinner and prop, prop nut  ) can cause a loose prop because of the clutch effect , also make sure your shaft ext is not bottoming out and not really getting the prop tight .Your spinner could also cause you a problem if it is plastic , try flying it without the spinner

See you at Brodak's

Will

[Wynn Robins]

it sounds like you have too much prime - OS motors DO NOT throw props unless they are flooded.......

[Steve Fitton]

A venturi full of fuel does seem like a bit much prime.  That hard backfire that blows loose the prop extension sounds like the result of an overly rich engine.

You might also be able to "hide" from the backfire by cranking the engine with an electric starter.  Use maybe half the amount of prime you have been using and zap it with the starter and see if it lights off that way.

[Steve Helmick]

 Scuff up whatever isn't knurled, if anything, first. Clean all the mating surfaces with acetone or dope thinner and allow to dry. Get out the JB Weld and glue the three pieces into one unit. I don't think you'll have anymore problems. It worked great for me, anyway.  If you later want to disassemble the parts, the heatgun will do it just fine.  Steve

[Brett Buck]

Scuff up whatever isn't knurled, if anything, first. Clean all the mating surfaces with acetone or dope thinner and allow to dry. Get out the JB Weld and glue the three pieces into one unit.

    And for goodness sake, bolt it all up tight before the glue dries to ensure alignment. I think the glue is pretty extreme but I can see why you might get around to that.

     Brett

[john e. holliday]

I have done what Steve has said to do the week before the fly in at the KCRC Field.  I didn't listen to the prop when I tried to burp the engine.  The extension stayed with the engine like it was supposed to.  If I had checked the prop before trying to burp engine there would have been no problem.  Got several restarts after tightening of the prop.  Have fun,  DOC Holliday

[Matt Colan]

A venturi full of fuel does seem like a bit much prime.  That hard backfire that blows loose the prop extension sounds like the result of an overly rich engine.

You might also be able to "hide" from the backfire by cranking the engine with an electric starter.  Use maybe half the amount of prime you have been using and zap it with the starter and see if it lights off that way.

Steve, I have the prop turning 9200 RPM.  This motor is running in a mostly 2 cycle, little 4 cycle going around the circle so it is not rich.  The plane won't fly a decent pattern if it is running any richer than 9200.  I did have it running even leaner but it bogged down going up on the third loop of the clover, so I richened it up two clicks and it runs fine now.

[Alan Hahn]

What kind of spinner are you using---assuming you are of course. Some times the ones with an aluminum backplate are pretty hard and the prop driver doesn't really bite into it.

Another question is whether the wood prop hub looks like it is compressing?

[Matt Colan]

What kind of spinner are you using---assuming you are of course. Some times the ones with an aluminum backplate are pretty hard and the prop driver doesn't really bite into it.

Another question is whether the wood prop hub looks like it is compressing?

I'm using a 2 inch Dubro plastic spinner.  The prop hub could be something to look at.

[Garf]

My OS S35 starts immediatly with a single choke. But it is an ABC conversion. Spray bar jet is pointing directly at the crankshaft.

[Steve Fitton]

Steve, I have the prop turning 9200 RPM.  This motor is running in a mostly 2 cycle, little 4 cycle going around the circle so it is not rich.  The plane won't fly a decent pattern if it is running any richer than 9200.  I did have it running even leaner but it bogged down going up on the third loop of the clover, so I richened it up two clicks and it runs fine now.

Oops, I wasn't clear last post.  By too rich I meant: too rich when you first flip it (because of the amount of prime you had in the venturi.)  Once its going, of course you set the needle wherever the motor is happiest.

[Matt Colan]

Oops, I wasn't clear last post.  By too rich I meant: too rich when you first flip it (because of the amount of prime you had in the venturi.)  Once its going, of course you set the needle wherever the motor is happiest.

Yes it starts off rich and then gradually leans out to the present needle setting

[Allan Perret]

I'm using a 2 inch Dubro plastic spinner.  The prop hub could be something to look at.

I dont like any of the plastic spinners that use a plastic backplate.  The teeth in the backplate dont have enought tooth to get a good bite.  Try the Great Planes plastic spinner with the aluminum backplate, much better grip especially on wood props.  Only slightly more expensive than the all plastic ones.
I also think you are using too much of a prime, 3-4 drops should be plenty.  Or try burping it 3-4 times before you put fuel in it to warm it up for the first start of the day. 

[Will Davis]

Matt,

I use a OS 35s in my Classic plane Skydancer , Stock OS 35S , 265 venturi,Tube muffler, On muffler pressure

My Starting procedure is this,

With the plane upright,Choke with your finger over the venturi for a couple, maybe three turns of the prop, until you feel fuel on your finger , remove your finger from the venturi, but just enough for it to suck in air , flip the prop hard  like you are trying to start the engine  four or five times , (no glow driver). this will help get the proper amount of fuel in the cylinder, but not too much to flood it .   Then put the glow driver on , Grasp the prop between  thumb and fore finger and rotate  CCW until you get a bump . Put Glow driver on . Then start like normal..

Hope this helps , Works for me

Will

[Paul Taylor]

Matt,
I am not one to give expert advice, but what the way Will tells you above is what I do but without the "bump". Chris Sterner uses OS FP's and gets one flip starts almost every time. Fill the tank, thumb over the vent and pull the prop over three times. You will feel fuel on your thumb. Then without the glow driver on, flip 3-4 times. Attach glow driver and with one hard flip it will (knock on wood) start first flip.
At least it is like this on Ryan's LA .46 Boxstock. Mine is a little harder to start but same process seems to work.
See you next week.

[Matt Colan]

Matt,

I use a OS 35s in my Classic plane Skydancer , Stock OS 35S , 265 venturi,Tube muffler, On muffler pressure

My Starting procedure is this,

With the plane upright,Choke with your finger over the venturi for a couple, maybe three turns of the prop, until you feel fuel on your finger , remove your finger from the venturi, but just enough for it to suck in air , flip the prop hard  like you are trying to start the engine  four or five times , (no glow driver). this will help get the proper amount of fuel in the cylinder, but not too much to flood it .   Then put the glow driver on , Grasp the prop between  thumb and fore finger and rotate  CCW until you get a bump . Put Glow driver on . Then start like normal..

Hope this helps , Works for me

Will

The only reason I put fuel in the venturi is because I can't get my finger in the cowl to prime it.  Tomorrow, when I fly hopefully, I'll put less fuel in the venturi and try to start it.  A report will come tomorrow if I fly, if not Saturday 

[Randy Ryan]

Matt,

I do this with all my inverted cowled engines. Its just a soft balsa plug that I ckoke with and it doubles as a storage plug.





Oh yeah, that's an OS .35S in there too.

[john e. holliday]

Jim Lee used to do that with a tool he made just for choking engines.  DOC Holliday

[Alan Hahn]

Jim Lee used to do that with a tool he made just for choking engines.  DOC Holliday

I made such a tool with a foam earplug---won't say if it was  used earplug.

[Glen Wearden]

I've been wondering what I could use to choke the LA40 in my Nobler ARF; well, I remembered that I had bought some blue rubber ear plugs at Wal Mart, but I didn't like them because they were too large for my ears, and very uncomfortable.  I just went out and stuck one in the venturi, and voila, I now have a good choking device.

Glen Wearden

[Matt Colan]

Here's what I did today.  The first flight on the Ares I put in less fuel than I did, which was a bout halfway up the venturi.  The prop got loose, so that was too much.  I tightened the prop and put the battery on and within 10 seconds it started.  The next flight I started with nothing just to see if it would start.  it didn't.  I put in VERY little fuel into the venturi, put the battery on, and now within 15-20 seconds of flipping it started.

in a previous post, I said the motor started out rich and gradually leaned out to the present setting, well on the second start, the motor just started right at that setting.  Also that flight, I must've sucked something up in the venturi which the end result was I had to, and I'm not kidding, pry my hand off the handle.

On Sunday, I'm going to get some ear plugs and put in the venturi, and choke it, then take the plug out and start the motor.

PS.  I asked my grandfather how my first flight was, and I'm guessing this is with pattern points, he said it was a good pattern, probably in the 480s, I finally got some of my maneuvers down in height.

[john e. holliday]

Matt,  just forget about pattern points and appearance when practicing.  Concentrate on the shapes and angles.  Have grandpa judge the shapes not you.  It looks different from inside the circle. 

Now as far as the prop coming loose do as  someone suggested.  Get some 60 grit sand paper and cut some discs to place between the thrust washer and spinner.  You might even have to plut one between the spinner and prop.  I just did that with my new Arctic Fox on a Brodak 40 that has never given me that problem before.  This was just putting oil in the engine to check my prop setting as I was finishing up the plane.  DOC Holliday

[Matt Colan]

Matt,  just forget about pattern points and appearance when practicing.  Concentrate on the shapes and angles.  Have grandpa judge the shapes not you.  It looks different from inside the circle. 

Now as far as the prop coming loose do as  someone suggested.  Get some 60 grit sand paper and cut some discs to place between the thrust washer and spinner.  You might even have to plut one between the spinner and prop.  I just did that with my new Arctic Fox on a Brodak 40 that has never given me that problem before.  This was just putting oil in the engine to check my prop setting as I was finishing up the plane.  DOC Holliday

I have a tendency to fly my maneuvers high, the bottoms are sometimes around 10ft, and he keeps telling me to bring it down, and that flight I did, and he said it was a good pattern, except my overhead 8s, which look fine to me except my last outside loop.  For some reason I pull it tighter than the first outside 

I do think i have the starting routine down now.

[Matt Colan]

I do think i have the starting routine down now.

Yeah right.  Yesterday we got our last flights in before Brodak and here's what came of it.  On the first start on the Ares, the motor backfired and the prop moved, so what came from that was I think I should burp it now before putting in a flight to get rid of that initial charge because I put in VERY little prime.  I got the motor started went out to the lines and after about 5 laps the motor leaned out to where it was screaming.  I landed and Grandpa said it was too lean, so he richened it up half a turn and gradually bring it in to competition speed.  The next flight was rich so I was only doing shallow wingovers and at about the 5th one the motor quit.  I was almost ready to pull the motor out and put another one in, until Grandpa said, let's put a different plug in.  The next flight, I thought was rich so I was doing wingovers and loops, but he told me I was actually flying at 5.0.  I thought I was flying around 5.2 or 5.3.  When I landed I turned the needle in 1 click and that would be it.  Grandpa decided to start it so we wouldn't be wasting time trying to start the engine.  This flight I put in a whole pattern and it was a good one except the overheads, for some reason I just can't seem to fly them well at all.  Grandpa timed me and he said I was flying at 4.8 at the beginning of the flight, and I went to 4.6 at the end, but I thought I was flying at 5.0.  It didn't seem to be flying THAT fast at all.

Well next flights will be a Brodak, so you won't here from me until after when I get back.  I plan on posting a bunch of pictures when I get back.