STALKER 46.........WHERE ARE THE EXPERTS

Stuka Stunt Main Forum · 17 of 17 known posts recovered · the forum listed 24 replies

GLBahrman · Jul 25, 2003 07:01 PM

LAST EDITED ON Jul-26-03 AT 04:16 PM (CDT)

Hi Guys,
I am looking for anyone with experience with the new Stalker 46. I just removed the ST 46 from my profile that worked pretty good and replaced it with a Stalker 46 as I was looking for a little more power.The Stalker has 2 gal. fuel thru it, but I haven't found the right combination yet. I'm not unhappy, just looking for advise. The Stalker seems to run best on 5% nitro. When I go inverted out of the reverse wingover the thing goes totally silent, kinda scary, then it picks up rpm and starts to run normal again thru the rest of the pattern. I'm running a plastic Dubro tank on suction modified for uniflo. I ran the same tank with the ST 46 on muffler pressure and it ran a great dependable 2-4 break. So the next thing I will do is try muffler pressure and see if it makes a difference. Any advise or comments is appreciated, Thanks......Greg

OK Guys,
I just got back from the flying field to no avail. Don't ask if I tried this or that because I did. 4 different brand plugs, different brand & size props. Switch to muffler pressure & makes no difference. Engine leans out when I go into the inside loops and doesent come back to 4 stroke..ever. This is one strong running motor in the 2 cycle mode it hauls astroids. Switched to super tigre needle assy, changed filter to a crap trap filter, switched all fuel lines. When I got home I pressure checked the tank and each individual fuel line and there are no leaks. Checked all the head bolts and they are tight. does the same thing with 5% or 10%. Added head shims, removed head shims, tried smaller size venturi's, I'm exhausted. I can do the pattern in 4 min. I even launched with the engine so rich the plane barely got off the ground, took a full lap to get off the ground. 6 laps later went into turbo boost mode. Of course I cleaned the tank and blew out the needle etc. A few years ago I had a r/c ship that acted the same way and it turned out that the sleeve was out of round when the engine was cool to warm it ran good but once it got hot and the sleeve expanded look out and hold on your going for a ride turbo boost mode!!! WHAT YOU THINK....SAY SOMETHING!!

Greg L. Bahrman

Bill Little · Jul 25, 2003 08:52 PM

RE: STALKER 46#1 source

My flying buddy ran a Stalker 46 on his profile. Didn't experience any problems, but he was running a standard metal uniflow tank. I say to try the muffler pressure.

Great engine by all accounts, and after he planted it in the asphalt, the factory repaired it (new case) VERY quickly!
Bill

Alan Resinger · Jul 26, 2003 12:09 AM

RE: STALKER 46#2 source

LAST EDITED ON Jul-26-03 AT 00:09 AM (CDT)

Greg,
I'm curious if you have an upright or inverted mounting. I built a new Classic model for this year and ordered a Stalker 46 RE for it. The model had a metal tank that could be run either as standard suction or uniflow. The engine almost quit on every inside manouver with the inverted mounted engine. Tried different props, plugs, fuel, tanks and everything elsesuggested on htis bulletin board to no avail. It always did the same thing on inside turns while outsides were perfect. I traded the thing for a ST46.

GLBahrman · Jul 26, 2003 12:13 AM

RE: STALKER 46#3 source

side mounted on a profile

Greg L. Bahrman

Crist_Rigotti · Jul 26, 2003 04:25 PM

RE: STALKER 46#4 source

What type of fuel are you using? Stalker recommends ALL sythetic oil fuel.

Crist Rigotti
"A driver trying to be a pilot"

GLBahrman · Jul 26, 2003 04:31 PM

RE: STALKER 46#5 source

power master 5% nitro, 18% oil, which of that 5% is castor which is acceptable according to Stalker but no more. Thanks for the response.

Greg L. Bahrman

De · Jul 26, 2003 04:47 PM

RE: STALKER 46#6 source

I'm not an expert, but have you changed the fuel tank as part of the troubleshooting process?

De Hill

Sammy Stunter · Jul 26, 2003 04:56 PM

RE: STALKER 46#7 source

Have you tried 4-cycle glowplugs? From my own experience with Double Stars (and the metallurgy is similar, very dense chrome and very high silicon content piston), they need VERY hot glowplugs. Some Stalkers in our area, but most have been 10cc's. This engine should not runaway, but that's what you described, so try a smaller prop, maybe an 11-5? What sizes and brands of props have you been using? Consider removing the baffles from the muffler to reduce backpressure and heating. The cutout on corners sounds like too large a venturi, too little compression, too cold a plug, too little nitro, or too much prop load, to me. If none of that works, try straight synthetic oil, tho I would not like that solution, myself.
Sammy

Brett Buck · Jul 26, 2003 05:01 PM

RE: STALKER 46.........WHERE ARE THE EXP#8 source

>I just got back from the flying field to no avail. Don't ask
>if I tried this or that because I did. 4 different brand
>plugs, different brand & size props. Switch to muffler
>pressure & makes no difference. Engine leans out when I go
>into the inside loops and doesent come back to 4
>stroke..ever. This is one strong running motor in the 2
>cycle mode it hauls astroids.

Your description is pretty much a prototypical "schneurle runaway" that used to happen when you ran a 40FSR or a stock 40FP with a 12-6 prop. Running it at higher RPM will probably make it run much more steadily, and on the right side of the power curve in flight. You don't mention what prop you are running but, I suggest getting a prop wil less ground load and pitch - I would guess a 12.25-3.75 APC might be a good choice. It might be stable in a 4-stroke at higher revs, or it may need to be in a 2-stroke to get a decent lap time, but it's usually a good idea to let it run like it seems to want to.

Brett

BRISTUNT · Jul 26, 2003 06:50 PM

RE: STALKER 46.........WHERE ARE THE EXP#9 source

You may be experiencing the typical overcompression deal. If tank issues are definitely ruled out. Try adding a couple of head shims.

The symptoms of overcompression on the Stalkers are:

Very fussy on the needle.
Switching to a 2 cycle and staying there.
Rich irregular 4 cycle.
Erratic switching.

Also the Stalkers are machined to match the typical European plugs which are longer than the typical long reach plugs we use. I spot face the heads of all Stalkers I sell. It makes them more tolerant to different plugs and fuels, especially if you use a lot of castor.

BRI

BudS · Jul 26, 2003 07:16 PM

RE: STALKER 46.........WHERE ARE THE EXP#10 source

Back plate leak?

Or To see if the uniflo is putting air in the gas line, you could switch your pickup to the uniflo pipe-but be careful of a shorter run.

Or vibraton may be foaming the fuel. Eric V, in our club, mentioned something you could mix with the fuel to cut down on foaming-but I can't remember what it was.

I second the suggestion for a APC 12 1/4 x 3 3/4 and let that puppy wind up. (if your not already doing that)
Just two cents worth from someone who has fought the same, very frustrating, battle.

Bud Shipley

GLBahrman · Jul 26, 2003 07:33 PM

RE: STALKER 46.........WHERE ARE THE EXP#11 source

Thanks to all of you. I will keep working it with all your ideas.
Sincerely, Greg

Greg L. Bahrman

downunder · Jul 26, 2003 09:39 PM

RE: STALKER 46.........WHERE ARE THE EXP#12 source

I had nearly identical symptoms with my ST G51 using zero nitro, 20% castor. No amount of fiddling with compressions, needle valves, venturis, plugs cured it. Until the day I ran out of my usual fuel and tried some 25% all castor I happened to have with me. It instantly went into a 4 stroke for the entire flight and has been like that ever since. I know Stalker recommend a low % all synthetic so if you don't want to use castor I'd suggest trying considerably more synthetic.

Igor Burger · Jul 27, 2003 12:41 PM

RE: STALKER 46.........WHERE ARE THE EXP#13 source

Greg, it depends what type you have. I you have side exhaust, then it is really typical runaway as Brett mentioned. But also rear exhaust version makes similar problems. My experience is, that inverted Stlaker runs rich on insides (both) and side exhaust outboard mounted Stalker runs lean on insides (rear exhaust does it less). Tank position typically does not solve it.

Brett also mentioned it is overcompressed. It is probably true, as those engines are done for 0% nitro. (but I never see Stalker from Modusa, it can be different) You probably do not have gaskets, so try no nitro fuel with COLD glow. If it helps, you have overcompressed engine.

The best result is probably low compression with hot glow. It should NOT reach totally steady 2 cycling – it prevents that asymmetry. Stalkers and Retro engines like to run in lean 4 cycling and without clear 4-2-4 switch – it is rather something more 4 cycling – less 4 cycling. You will explore it will be able to turn rather larger prop at “tractor” run.

igor

GLBahrman · Jul 27, 2003 12:46 PM

RE: STALKER 46.........WHERE ARE THE EXP#14 source

LAST EDITED ON Jul-27-03 AT 12:47 PM (CDT)

THANKS...SIDE EX

Greg L. Bahrman

Brett Buck · Jul 27, 2003 01:10 PM

RE: STALKER 46.........WHERE ARE THE EXP#15 source

>Brett also mentioned it is overcompressed.

I think that was our buddy BRISTUNT, not me. I'm a big fan of going with the flow as far as stuff like that is concerned - I strive to exhaust all possibilities of external changes before I pick up wrenches, screwdrivers, or Allen keys!

Brett

Igor Burger · Jul 27, 2003 01:39 PM

RE: STALKER 46.........WHERE ARE THE EXP#16 source

>>>I think that was our buddy BRISTUNT, not me.<<<
Hups ... sorry Brett and Bristunt ...

>>>I'm a big fan of going with the flow as far as stuff like that is concerned - I strive to exhaust all possibilities of external changes before I pick up wrenches, screwdrivers, or Allen keys!<<<

I also, but the flow must go my way! If not, my box contains also hammer for quick flow regulation