Starting inverted engines and a stooge dilema

[Steve Agrella]

I two new built up planes, a Nobler and a Oriental ARF, I have a LA 46 in  the Oriental and a LA 40 in the  Nobler, I have always had profie planes, my question is how do you start these upside down motors without having to flip the plane over.
Doing this with a helper is obviously no problem however I'm retired and don't want to rely on friends that are not always available when I am, so I like to fly off of a stooge.

I've heard all of the mumbo jumbo horror stories of stooge near misses, I have never had a mishap, yea I know it's not a matter of if, its a matter of when blah,blah, blah...lol.

Anyway looking for starting suggestions for inverted motors.

[Jim Kraft]

Not sure what you are running, but this works for me on my older Foxes and McCoy Red Heads. Bring the piston up to where it is just starting on compression. Then cover the intake with your finger while pulling the prop to bring the piston to top dead center and release your finger while pulling the prop on through. You can hear a slight suction at the intake and it will suck fuel into the engine. Doing this about three times should be enough. Then flip the prop a few times to distribute the fuel and hook up the glow driver. It should start within a few flips and maybe on the first one. If you just choke it normally the fuel will just run out on the ground. Hope this helps.

[Steve Helmick]

Same basic deal. Choke it enough, not too much, hot battery, flip prop. A lot of the "trouble" is myth, IMO, because excess fuel will run out the venturi and not (NOT!) into the crankcase. Is it possible to flood the engine? Yup, doesn't matter how it's mounted. Gotta learn what it needs, in all cases.   Steve

[EddyR]

Jim is wright on but tell us what motor you are using as some need more or less priming. Practice before going to the field. Also before filling the tank and connecting the lines hold the plane inverted and  choke the motor and run of the prime.
Ed

[Tim Wescott]

... but tell us what motor you are using as some need more or less priming ...

I have a LA 46 in  the Oriental and a LA 40 in the  Nobler

My LA 46 (in a profile) needs three turns of prime when warm, 5 when cold.  I dunno how that works out in an inverted installation.

[bob whitney]

what is said should get u in the ball park.  if it runs out the prime a few times but dose not start, hold it off the ground and tilt the nose down just a bit and it should pick up the prime and run

[Tim Wescott]

what is said should get u in the ball park.

I forgot to mention that part -- every engine I have is a bit different, and the amount of prime you need varies with fuel and air temperature, to boot.  So -- plan on messing around to find the right ritual.

[Andrew Hathaway]

I prime almost everything the same way...  I pull the quantity of fuel I want to use into the syringe, then another 1/8-1/4 oz further.  Then I push all but that 1/8-1/4oz of fuel into the tank, slip on the overflow cap, and I push on the syringe until I see the fuel fill the line and start to dribble in the venturi.  With an inverted engine, I watch for a drop or two from the venturi.  Then I flip the prop swiftly several times, usually I can feel and hear when the prime has lubricated the crank and piston.  At that point I hook up the battery, and a flip or two later the engine is either running, or I goofed and need to choke the engine a bit more.  Most of the time, it starts right up on the first try.

I don't like choking the engine to pull the fuel from the tank up to the venturi.  Sometimes it takes more or less turns with the venturi covered to draw the fuel up to the engine.  Using the syringe I know how much fuel is in the tank, and that the fuel line is filled up to the intake.
 

[Jim Kraft]

I have watched Andrew do this many times and he has it down to a science. It works extremely well.

[Steve Agrella]

Thanks very much for all of your replies, I'm going out today so I'll get back to this thread later today to report on my experience at he field.

[John Rist]

Thanks very much for all of your replies, I'm going out today so I'll get back to this thread later today to report on my experience at he field.

All will tell it's not cool But I use an electric starter.

[Allan Perret]

Its a matter of getting just the right amount of prime for any given engine and installation.  I use the 2oz glue syringe from SIG for priming, its shoots a small needle like stream up into the venturi.  It is the easiest way I have found to get a consistently accurate prime into the engine.  And remember this while priming, if you rotate the prop/crank CW up against start of compression, the port in the crank is closed, and if you rotate CCW it is open.  When you are 1st learning what your engine wants for prime, try it with port closed (CW).  If it doesn't go, then open port (CCW) and prime again.

[Joe Yau]

I find inverted mounted engine is actually easier to start then upright.  but you have to know how much prime to put in as mentioned above. Assuming it is above around 8C+ degree. (otherwise lighter fliud is needed)  For my first flight.. I fuel up the plane and hold it vertically with finger over the venturi and flip the prop till its about to starts to whip back and forth, then put the plane back down.  put glo-driver on and bump it off the compression in the reverse direction.. It usually fires right up 9/10 times, and between flights, just choke it till the prop starts to whip back & forth freely on the ground.. pretty much the same as previous. (usually 3 or so flips will do)  careful not to flood it.  then just bump off the compression should fire up.  This method has worked on my Stalker .61RE and a OS .40VF/piped for years even in -3C degree (with lighter fluids).  

[Brett Buck]

I two new built up planes, a Nobler and a Oriental ARF, I have a LA 46 in  the Oriental and a LA 40 in the  Nobler, I have always had profie planes, my question is how do you start these upside down motors without having to flip the plane over.
Doing this with a helper is obviously no problem however I'm retired and don't want to rely on friends that are not always available when I am, so I like to fly off of a stooge.

I've heard all of the mumbo jumbo horror stories of stooge near misses, I have never had a mishap, yea I know it's not a matter of if, its a matter of when blah,blah, blah...lol.

Anyway looking for starting suggestions for inverted motors.

  Joe is right, I pretty much hate starting upright engines, particularly on the test stand.

   It's all about technique to learn the required method. I usually burp piped engines although with some of them, it's possible to get them going inverted, even without burping. I never had any luck with that with the VF or the PA, but the RO-Jett, for whatever reason, is much less prone to locking up from the oil dribbles, and I have occasionally managed a cold start with it on its feet. 

    It's much safer to choke the engine when it is inverted. Unless you grossly overdo it, any excess fuel runs out on the ground as soon as you take your finger off the intake. You need to get just enough fuel in the engine to loosen it up, and to get enough fuel in the cylinder to get a start.

  A typical sequence, once you get the first start, is:

Cooled off (more than about 20 minutes):
battery off
finger over intake, flip through compression forwards 5-6 times
remove finger, keep flipping forwards smartly 4-5 times to aerate the engine
Attach battery, back-bump smartly (DO NOT flip through backwards, just sling the prop up against compression backwards)
should start in 1-2 tries
 
if no start,detach battery flip through listening for slightly "juicy" sound
    If "thud", not enough fuel, choke some more, aerate some more\
    if "sloshy", too much fuel (rare), flip forward many times to aerate some more without choking
    if locked or close to locked, flip airplane over, tilt airplane to exhaust-side-down, rock prop back and forth to release fuel out the exhaust port, flip a few time, return to "aerate" stage (no more choking).

 (hot  - just a few minutes since last run) - same, except much less or no choking. If overchoked, engine will feel "dead" with relatively low compression. This is "shrinky piston syndrome", solution is to remove battery, flip forward many times (10-15) until you feel the compression come back, then attach battery and back-bump.

  This should be refined until you get reliable starts, but it can be mastered in a few flying sessions.


   CAUTION - ALWAYS, repeat ALWAYS, restrain the model and expect the engine to start any time you have fresh fuel in it and allow the prop to move. With AAC/ABC engines in particular, no-battery starts are *common occurrences*, particularly when you get you procedure refined. Also, ALWAYS, repeat, ALWAYS restrain the prop while you are attaching the battery. It is also quite common to get a burp or start at the instant the battery is attached, and you are reaching through the prop blades to stick it on the glow plug.

   BTW, "blah blah blah" on the stooge, but be very careful, the previous warnings were not a silly joke, there have been numerous dangerous accidents when flying by yourself with a stooge. They sure as hell weren't "mumbo jumbo".

   Many people with vastly more experience than the average modeler have nonetheless had accidents, and you are not in any way immune to it.

    Brett

[Steve Agrella]

I went to the flying field today with my brand new Oriental, the La 46 gave me fits, come to find out whomever I purchased the engine from put the wrong needle valve assembly and Venturi on it.

I spoke to Erik Rule today and he pointed me in the right direction, I purchased a needle valve assembly and Venturi from him.

After talking to Erik I also found out that I had my tank plumbed incorrectly which explained the 15 seconds of flight time, so I came home and fixed everything that Erik told me to ficfixing just waiting for the new needle valve assy.

The plane flew great didn't get to do much with it but line tension was good and glide on it was effortless to land...lol got see it go around two times, can't wait until the next session.

Been a comedy of errors but hey I'm learning all over again how to tinker with theses babies, I love it.
Thanks for the help and the concerns about my stooge, I do not take it lightly, accidents do happen guess I've been pretty lucky or well prepared, probably it bit of both.

[Steve Helmick]

Assuming you're flying on grass...best tip possible for using a stooge is to stake down the safety thong on the handle with a large screwdriver (not the electric kind). Uh, you are using a safety thong on the handle, right? A 'search' should turn up more good safety tips for launching stooge use.  Steve