STALKER ST66 LT-LS ENGINE

[KEITH McCRARY]

Has anyone seen or used this engine. At 220 grams it seems very light.                                                  Engines
Working volume   10.85 cc
Turnovers   7200-8200 rpm
Number of cycles   2 cycles
А type   Glow
Glow plug   КС-2
Bore   24 mm
The piston stroke   24 mm
Cooling   Air
Weight   220 grams 
                                                                                                                                                                      https://technohobby.com.ua/engines/engines-stalker/                                                                                               

Keith McCrary                 

[Massimo Rimoldi]

Hello.
The weight indicated on the website is wrong, the engine weighs 320 gr.
I can not give you advice because I've never used it.
If you use the search function here or on SSW, you can find a lot of useful information.

Massimo

[Brian Gardner]

Good engine. It tends to like a little less oil than the smaller Stalkers.

[Istvan Travnik]

My friend started to use it one year before, and all of his experiences were positive.
As I heard, this is the best of the bigger Stalkers.

[M Spencer]

Running a RE , in the P-51 at the moment . on a 12 x 5 Top Flite . Gunna trya 13 x 6 APC .is one stamped 66 , maybe the First .

Seems to like a cooler plug . Brewed 3 % N. for next . Fireball & Enya 3 wernt right , STigre plug cured the putt putt , Land ,
backfire & Reverse Taxie ! from one flight .

only seems as Authoritive as the S Tigre 51 on T F 12 x 5 cut to 11 1/2 . or cammed up on the 10 x 6 3 Bl Tornado .

a 12 x 6 & the 66 didnt want to slow down , must be a real clean aeroplane . 

Instruuctions go for Synthetic . I use 50/50 .

Some put in a flasher N V A .

 

p s , think ' the break ' was around 8500 when we put the Tach on it , maybe on the 12x6 Bolly  .

[Ruslan Kurenkov]

Has anyone seen or used this engine. At 220 grams it seems very light.                                                  Engines
Working volume   10.85 cc
Turnovers   7200-8200 rpm
Number of cycles   2 cycles
А type   Glow
Glow plug   КС-2
Bore   24 mm
The piston stroke   24 mm
Cooling   Air
Weight   220 grams 
                                                                                                                                                                      https://technohobby.com.ua/engines/engines-stalker/                                                                                               

Keith McCrary                 

Hi Keith
I know this engine very well.
 In 2015-2016, I made 800 training flights on this engine together with my friend (also a pilot of F2B) who during this period made 600 training flights. Our junior, a member of the Ukrainian national team for 2016-2017 performed 1000 flights on this engine. I installed, regulated, gave all the recommendations for tuning the engine, the composition of the fuel, the installation of the fuel filter, the installation of the fuel tank, the installation of the propeller and the installation of the spark plug and another needle for adjusting the supply of the fueled junior engine Stalker 66 to the old model F2B Sergei Solomyunnikov .
I personally think that this is one of the best two-stroke engine for the F2B models today. The weight of my F2B model on which the Stalker 66 was installed was 1870 grams (66oz). The engine very easily pulled this weight across all the figures. The length of the lines was 65'(0.0145 brass). The propeller for this engine is only a wooden (birch) 350mm (13.8in) diameter and 150mm (5.9in) - pitch. Candle of incandescence ОС МАХ №5 (Hot). Fuel only without nitromethane. Methanol 84%, castor oil - 8%, synthetic oil - 8%.
The fuel supply needle must be replaced with a needle from Discovery Retro .60 or Super Tiger .60V. Start the engine preferably in the opposite direction with a strong push not reaching the piston to the glow plug. Typically, in 99% of starts, the engine starts with the first movement of the hand on the propeller.
The weight of the engine with a volume of 10.85 cm (.66) - 320 grams (11.3 oz).
The weight of the engine with a volume of   9.96 cm (.60) - 325 grams (11.4 oz).
For 1000 flights the engine operation and the piston pressure state have not changed at all. The engine will make no less than 2000-2500 resses without problems.
I know very well the manufacturer of these fine engines from the city of Kharkov Ukraine - Oleg Korotchayev (F2B pilot from Ukraine). We have been friends for many years, and I've only used its engines for my F2B models for many years.
If the athletes reading this forum have any questions on the Stalker Engines 60, 66 or 76 - then please ask. I will definitely give you a complete answer to any question. I and my friends Sergei and Andrei have the biggest experience of operating and adjusting the Ukrainian Stalker engines.
Regards
Ruslan

[Frank Wadle]

I've used the Stalker 66 for about 2 years in my Big Kahuna design.
It was the best engine I ever tested in this ship. It has a lot of power and runs rather smooth. The 4-2-4 break is relatively soft. Vibration is much less than other engines of this size.
It starts very easy and is overall easy to operate. It responds nicely to needle setting changes and is not very weather sensitive. You can use a wide variety of fuels, props and plugs and it all seems to work fine.
Here is my setup:
Fuel:       80% Methanol, 10% Castor, 10% Motul Micro 2T
Tank:      Uniflow, I used about 140 ml per flight
Prop:       13,4” x 5,5” wood (Yatsenko)
      or 13,4” x 5,5” BE Carbon (Yatsenko copy)
Plug:      KC2 (Russian) or Enya 3
Muffler:   Original Stalker with a 10mm silicone tube extension about 5cm long

I’ve also tried bigger props up to 14.2” with good success, but the landing gear was not long enough for a safe operation so I switched back to 13.4”.

Overall I was very pleased with this engine. I think it is better than the Stalker 76. It has comparable power and it is much lighter (40-45g) and runs better.

[Frank Wadle]

Actually, if you want a really good engine of that size, then go for the Retro 68.
More power.
And the best stunt run I ever had!!!
The weight that tochnohobby is listing is not correct.
https://technohobby.com.ua/engines/engines-fora/eodr69.html
The weight is about the same as the Stalker 66

Regards
Frank

[Walter Hicks]

Frank does the Discovery Retro have to be side mounted to run well?

[Frank Wadle]

No, it doesn't have to be side mounted to run well.

I use it in both configurations, side mounted and inverted.
Both run very well.
With inverted you'll always have a little asymmetry in engine run and you have to find a compromise for the tank position that reduces the asymmetry to a minimum. But overhead eight one loop is a little lean, the other a little rich while in horizontal eight it is opposite. That means improving the horizontal eight symmetry messes with the overhead eight symmetry.
But I think this is the case with all engines. Some just show it a little more than others.
In my other plane the engine is mounted about 15° down (almost horizontal). Then the symmetry is much better than inverted.
I even had a plane where the Retro 68 was mounted full horizontally and that worked also very well. I don’t quite see a reason for the 15° down configuration.

Don’t get me wrong; even inverted the Retro 68 is a wonderful engine. The above mentioned effect is rather small and could be further reduced with a more inboard tank position. Then the engine would go to a full 2cycle in the overhead eight and the symmetry would be better.

[Massimo Rimoldi]

No, it doesn't have to be side mounted to run well.

I use it in both configurations, side mounted and inverted.
Both run very well.
With inverted you'll always have a little asymmetry in engine run and you have to find a compromise for the tank position that reduces the asymmetry to a minimum. But overhead eight one loop is a little lean, the other a little rich while in horizontal eight it is opposite. That means improving the horizontal eight symmetry messes with the overhead eight symmetry.
But I think this is the case with all engines. Some just show it a little more than others.
In my other plane the engine is mounted about 15° down (almost horizontal). Then the symmetry is much better than inverted.
I even had a plane where the Retro 68 was mounted full horizontally and that worked also very well. I don’t quite see a reason for the 15° down configuration.

Don’t get me wrong; even inverted the Retro 68 is a wonderful engine. The above mentioned effect is rather small and could be further reduced with a more inboard tank position. Then the engine would go to a full 2cycle in the overhead eight and the symmetry would be better.

I agree, the following is the exact transcription of a Yurii email from a few years ago.

"The 68  works  exact the same as 60(76 have little bit another character ofbreak)   but  more  powerful.
In reality inside it is the bigger copy of 60.
I had started to use horizontal cylinder location  because  the engine  have  symmetric position  in normal  and inverted  flight  and maneuvers.
It does the  engine  work more symmetric. It was the single reason.
However,  possible to use  it  vertical  too, I think, just it is need to find   the   best   tank   position  for compensation    of possible asymmetric   engine
work. 
You can feel some asymmetric in the normal and inverted maneuvers.
More   RPM (aerodynamic lighter prop, it means less pitch or diameter), it is less  asymmetric too (from  my experience).
Thank you,
Best wishes   Yuriy"

Regards, Massimo

[Lauri Malila]

According to Yuriy, the reason is simply esthetic. Totally horizontal engine looks a little stupid.

L

[FLOYD CARTER]

This one appears to have the muffler bolted on.  Much better idea than one Stalker 51 I have, with muffler pressed in with "O" ring.  Have to replace O ring after 3 or 4 flights.

[Lauri Malila]

In that case you have a wrong type of O-ring, Floyd.
A good viton ring lasts a very long time, I replace them only when I need to remove the engine or muffler from airplane. Silicone rins are even better but more fragile to handle. In my latest headers I have 2 rings; one in Viton and a second one, closer to engine, in silicone. That way the silicone only seals but does not have to take the mechanical loads.
Even better if you wrap 2-3 layers of the thin white plumber's teflon tape around the O-rings.

Lauri

[M Spencer]

Have heard of this ' assymytry ' re the Stalker 66 .

Intrestingly ? , Mine I got of Eather , who from Minato . Brian says it is ' the Prototype ' 66 .

His ( Brians ) Opinion is THIS engine Does Not suffer from assymetric issues , mounted inverted .
I have it Inverted in my semi scale P 51 . 60" Span .

Asside from pre ignition-ish , The Super Tigre plug evened it out . Now ive got a custom butchered - - - Er, Fitted 
Fibreglass cowl , muffler 1/4 ish exposed ( the Short Neck Muffler from the 76 , to fit the existing plane .

I may even go flying it tomorrow . Id mixed 3% nitro Fuel for the last mission , but didnt use that or the 66 .
Younger Days Nitro was N/A pre N.Z. drag race era .So were used to that & OS's which were ok without .

A prime of Nitro Fuel in the G-51 in cooler climates ( running in etc ) has it lit up instant . Likely a good idea for comps ?

Will post further opinionated tripe as it accumulates . Facts on assymetric behavior on the 66 would be seriously contemplated .
May measure the timing on mine , for a check . tho I think I did & was 130 / 110 . But mayve been the 76 & youd think Id ive written it down . Incidently Brian said he used , or to use , 20 % nitro ( for more tourgue ) & syntetic oil .
Both when I aquired them , and later asking to check , tho thinks 5 - 10 % nitros adequate .
Amwerican influance here gets mental blockage at mention of No Nitro . 
Bolted the 13 x 6 APC on it, last night . didnt think to take a picture of the instalation .
Out with the camera . Wots the best way to clean a engine / keep it clean .  Please .
Is brake cleaner aerosol ' A Bit Harsh ' .  ( it was on special  )

[Jim Catevenis]

As info, Tom Dixon is the sole distributor of Stalker engines in the U.S.A.  I spoke with Tom about this thread and he mentioned that he currently has a Stalker .66 in stock.  For additional information about Stalker engines,
contact Tom at (770) 592-3279 or by mail at:

Controline Sales
315 Santa Anita Ave
Woodstock GA 30189-7180 

[Brett Buck]

Both run very well.
With inverted you'll always have a little asymmetry in engine run and you have to find a compromise for the tank position that reduces the asymmetry to a minimum. But overhead eight one loop is a little lean, the other a little rich while in horizontal eight it is opposite. That means improving the horizontal eight symmetry messes with the overhead eight symmetry.
But I think this is the case with all engines. Some just show it a little more than others.

   I don't think so, and there are a lot of factors affecting it, some of which you can fix with normal adjustments, and some you can't. But the problem is one of the most important - now that everyone has enough power and enough reliability for any conceivable purpose.

    More or less everything we (David, Ted, and I) has centered around resolving this issue, back to Ted discovering the phenomenon (or at least being among the first to fully appreciate the impact of it) in the late 70's.

     Brett

[Lauri Malila]

The only good solution for this issue is to find a cylinder orientation that counteracts the asymmetric behaviour. I recommend to start from cylinder tilted 45 degrees down from horizontal, and fine-tune from there on.
Playing with tank height is fundamentally wrong, that way you are merely compensating one fault with another.
Ideally, tank height should ONLY be adjusted to acchieve symmetrical engine speed in both STATIC positions, upright and inverted, that is.
Even when the root of problem is elsewhere, more accurately in a discontinuation in fuel/air flow, there is usually a few things to be done to make asymmetry smaller; hotter plug, higher compression ratio, head design that makes top of power curve more flat (nice parabole with minimum squish band), less prop load.
Is it just that because people are so stuck with the classical nose construction, they keep banging their heads in wall?

Lauri

[Igor Burger]

The only good solution for this issue is to find a cylinder orientation that counteracts the asymmetric behaviour. I recommend to start from cylinder tilted 45 degrees down from horizontal, and fine-tune from there on.

Yes, I do not think that Retro tilted down was only apearance solution. Friends around had few Retros with very asymetric run. Typical is rich in positives while inverted and rich in negatives while side mounted. Logical solution was motor oriented 45 degrees in between. That is what I did also with piped OS max 46 LA in my 2001 ship:

http://www.netax.sk/hexoft/stunt/the_max.htm

and what I repeated in next year ship (used on my first WCh in Sebnitz and placed 10th):

http://www.netax.sk/hexoft/stunt/the_max_ii.htm

worked perfectly. I even never needed to move the tank (in both) :- ))

[Brett Buck]

The only good solution for this issue is to find a cylinder orientation that counteracts the asymmetric behaviour.

<<  snip >>
Is it just that because people are so stuck with the classical nose construction, they keep banging their heads in wall?

    OY GEVALT! The old "everyone is stupid but me" gambit. I agree that the phenomenon is a real problem and it has dominated our (David, Ted, and I) experimentation over the last 15-20 years and Ted going back to the late 70's. It is much more marked around here than anywhere else in the country (which is a clue to the cause).  It is essentially a defect in the engine design, but it certainly can be overcome. But I think it requires "engine guys" to disregard some of the common knowledge and their own experience to overcome.

    The reason the engines are all mounted as they are is because they are still judged for appearance and it's almost impossible to make a neat and practical installation that permits the engine and pipe to be mounting at experimental angles (and every engine and individual example of an engine might be different - as documented 30+ years ago), and still look like it was intended to work that way.

     I had a much longer explanation on what we (mostly David and I, with abundant assistance and insight from smart people like Frank Williams) have been experimenting with, very successfully, to deal with the run asymmetry issue. But I am not in the mood for an argument over the topic for the next 2 weeks or getting told I am an idiot or incompetent again - both of which are potentially valid points with some sound justifications!

     Brett

[Lauri Malila]

Brett,

Calm down. Nobody is calling you that.
It's a pity that you have the appearance judging as a limiting factor, to me it's not a valid reason.
I am not very smart but I 'm quite stubborn. And I have spent quite a lot of time to prove the possible causes right or wrong (more often wrong:)). But there are really smart people involved in our project, so help is allways available when I run out of brain capasity.
 It's true that Ted has recognized the problem long ago and since then you have come up with an idea what's going on and how to live with it. But I doubt (let me know if I'm wrong) that you have done the same kind of testing as I, some results of which are clearly against some common opinions over here. What I mean is the possibility to run the engine in both directions and all the possibilities that our piston scavenging and porting offers for experiments.
Regarding my previous comments that caused your burst, they were about how to live with an engine that suffers from asymmetry and how to deal with them correctly. And unfortunately, tilting the cylinder is the way to go.
Of course there are engines without issues, kind of one hit wonders, and it would be interesting to study them more closely.
Anyway, I do apologize for pissing you off.

Lauri

[KEITH McCRARY]

Rusian and all, thanks for the information.

[Brett Buck]

Calm down. Nobody is calling you that.

   OH, it's not you and you weren't calling me anything. It has happened multiple times in the past with a few others and I always get a few people who just get on me about daring to contradict "stunt lore" and "engine lore", and I just didn't feel up to having another go-round just now.   

     I think you are doing some interesting things and I encourage you to continue. You are well ahead of the game in being willing to admit the problem exists - which puts you well ahead of many self-styled stunt "engne guys" some of whom claim, with their cheering sections providing histrionic support, that such things never happen.

     The essence of my mega-post (that I omitted) point is that making them run predictably and reliably for stunt requires (in my opinion) doing some things that are *diametrically* opposed to what decades of engine development for power/specific output/volumetric efficiency suggest.
 
  No offense taken at all, my fault entirely for leaving the wrong impression.

     Brett

[M Spencer]

Not Me.



from :http://forum.rcdesign.ru/f95/thread369820-7.html

Bit of sparing on 66 there . Translates on Tanslate . 

[PJ Rowland]

Run assymetry on the 75 caused me to go electric.

No matter what I did.. besides lauri making new heads5.. i couldnt resolve it.. i could mitigate it.. but never dissapeared.

Meh..

[Igor Burger]

That video shows also run asymetry - rich in positives, and it is so strong that it corrupts shapes of square eight, it is clearly visible that descending segment is rich in positives what makes it slower than the opposite side and that makes corner too high and pilot must push model down to get proper altitude in the middle.

[Lauri Malila]

Heads just help, PJ, but don’t cure the problem. L

[PJ Rowland]

Yes ive played with heads also.. but never machined my own.

Your a swiss watch god

[Lauri Malila]

Yes ive played with heads also..

Looking at the track record of that PA of yours, maybe that’s the problem

[M Spencer]

So You Cant Beat a Super Tigre 60 , then .  . .

[Brett Buck]

Run assymetry on the 75 caused me to go electric.

No matter what I did.. besides lauri making new heads5.. i couldnt resolve it.. i could mitigate it.. but never dissapeared.

   David got his working pretty well.

    Brett

[Brett Buck]

That video shows also run asymetry - rich in positives, and it is so strong that it corrupts shapes of square eight, it is clearly visible that descending segment is rich in positives what makes it slower than the opposite side and that makes corner too high and pilot must push model down to get proper altitude in the middle.

      Agreed, this shows the usual rich insides/lean outsides that is almost always the way it works. But it is a pretty mild case and most people would be a lot better off if they could get theirs to this low level. It's not bad at all, but still not quite right. It's small enough that I can't be entirely sure that the problem is not that he is making the outsides slightly smaller, causing more load on the engine, and making it go slightly leaner.

     I have seen people having the engine run dead 4 through the insides to the point it sounded like it was going to quit, to hard squeaky lean in the outside part of the square 8. The worst I ever saw/heard (aside from my Royal 45 as previously discussed), the outside part of the square 8 took maybe 3/4 of the time it took for the insides, and the airplane was driven towards the ground in the left descending leg like it was launched from a catapult.  And they *never noticed* and when it was pointed out, launched into hysterical defense of the engine, and then provided multiple conflicting explanations for why it was better that way. Both Paul Walker and I, working almost independently, had *exactly* the same problem with the same engine and could only slightly reduce it, so we knew what to listen and look for. The same guy also failed to seal his spraybar to the case, and he is the one I could detect as soon as he started the engine, while I was standing in the scoring "pagoda" at Munice a few hundred feet away.

      Brett

[Brett Buck]

So You Cant Beat a Super Tigre 60 , then .  . .

  Aside from the last 30 years or so, and the one exception was a very close call...

    Brett

[Randy Cuberly]

I personally believe that a good pipe setup running pipe pressure on a PA65 with a properly sealed needle valve assembly almost completely mitigates this problem.  At least it did on my Whitely Shoestring.

Playing with nitro content can also help it a lot!  Yes I know none of this applies to the Stalker66 but then I don't use one!

Randy Cuberly

[Allan Perret]

The same guy also failed to seal his spraybar to the case,
 

Hey Brett: what do you use to seal sparybar ?

[PJ Rowland]

Brett...

Daves engine does the same as mine...
It leans out in the outside.. he knows it.. I know it.. and noone ive seen run a 75 has got it right..

I changed EVERYTHING..
3 different spray bars machined up.. trialled bigger bore.tanks. fuel pumps.. different pipes..  it never went away.

[Brett Buck]

Brett...

Daves engine does the same as mine...
It leans out in the outside.. he knows it.. I know it.. and noone ive seen run a 75 has got it right..

On the occasions it has done this, we were swapping engines and doing test flights after dark to see if it worked - at the Team Trials!

     Brett

[Randy Cuberly]

On the occasions it has done this, we were swapping engines and doing test flights after dark to see if it worked - at the Team Trials!

     Brett

I witnessed many flights of Davids PA75 here in Tucson last year and saw no such asymmetry!  At least nothing that was either audible or visible from outside the circle!

Randy Cuberly

[Lauri Malila]

I witnessed Davids flights i cold and windy Hungary some years ago and noticed clear asymmetry issues.
So, this problem is strongly affected by running temperature and glow plug characteristics.
In cold I reduce cooling by adding big O-rings over cooling fins.
That is also why I’m interested in trying a ceramic combustion chamber. I have material- and machining issues sorted out, just have to find some time to make it.
Another thing maybe worth trying is to connect an adjustable air-box, a Helmholz resonator, to bottom of crankcase. It might well be the most direct attack to the issue, I feel allmost everything else is either just making the problem smaller or compensating one fault with another. L

[PJ Rowland]

Well.. Ive seen it fly a few times and although im loathed to critique a world champion.. the facts remain. It does it.. it did it in perth.. it did it in napa. it did it in muncie..
Others have seen it.. as noted by lauri..

I guess it comes down to having an objective opinion vs one based on emotion.

I get it.... and i will admit the 65 doesnt seem to suffer from the same issues.

But I didnt mean to topic jack it.. the stalker 66 is a nice engine.. not nearly as powerful as even the pa51 but a different operation range.

[PJ Rowland]

Besides... its not really a major issue if your good enough to fly against any potential assymetry.

To prove my point further... even Orestes shark at the worlds in Perth had assymetry differences.. the outsides were faster.

I filmed and timed the manouver sequences and compared the total speed difference from entry to exit. From flight to flight you build up.a general picture thats fairly consistent
 

The lap times were the same.. but manouver times were certainly not the same.

Outsides were faster.. consistently by almost 1 full second on some consecutive manouvers.

But it sure looked clean and 1 spot compared to the others in the final.

[Ruslan Kurenkov]

the stalker 66 is a nice engine.. not nearly as powerful as even the pa51 but a different operation range.

Hi
My experience with Stalker 66 suggests that this motor works very well only with propellers of diameter 350mm (13.8 ) and variable pitch with decreasing. 160mm (1/3 of the axis), 140mm (2/3 of the axis) and 120mm (5/6 of the axis of rotation).
The second condition is the amount of oil not more than 16% (8 + 8 )
If you pour more oil, the motor starts to lose power due to a decrease in the amount of methanol, it also starts to get hotter and immediately there is a deposit on the piston and on the head of the engine. This deposit leads to an even greater loss of power and overheating.
It is very good in the 66th Stalker in very hot weather to add to the fuel 1-1.5% nitromethane.
I started using Stalker 66 right after Discovery Retro 60 - one of the best motors of all time (now DR 60 is no longer produced).
I immediately felt a small increase in power (10%) and a very easy and stable launch. The engine easily worked on all the figures with the model 1800gram (64oz), the control line 65ft, 0.0145.
If the weight of your aircraft is more than 1800gram (64oz) then it is necessary to use a Stalker 76.
Regards
Ruslan

[proparc]

Anyone have any experience with this guy?

[Ruslan Kurenkov]

Anyone have any experience with this guy?

Hi
I and my friends have a very large experience of operating this engine.
Your photo shows Stalker 76 with a side exhaust.
It was with this, the side exhaust installed the engine of my friend Sergii Solomianikov on his model F2B. He has been using this engine for more than 10 years and has a colossal operational experience that he constantly shares with me. This arrangement of the silencer is most convenient for servicing the fuel tank, because the silencer is located directly under the tank when the engine is mounted in a view from the front at 225 degrees. At the same time the fuel in the tank is absolutely not heated by the temperature of the muffler.
To work the engine as a whole the arrangement of the muffler back (as at me) or aside (as on a photo) - does not influence.
If you or the forum participants have any questions about this engine then write, I'm always ready to help.
Regards
Ruslan