Stalker Stunt Engines

[Curare]

   OK, but I am not sure what your point would be, I am quite well aware of the numbers for a OS 40VF. And my #1 RO-Jett has the same 144 degree exhaust timing - that was the "mistake" they made, they started with 140 degrees, wanted to move it to 136 just like the PA, and Dub turned the crank the "wrong" way (or more likely, added .004 instead of subtracting .004 in his CAD milling machine) and wound up with 144 instead.

 I have tried all three versions, the longer the exhaust timing, the smoother the break, same with the OS VFs, the best individual 40VF has 145 from tolerance stackup, the least is about 141-142. (although all are OK). I have run 136, 140, and 144 degree versions of the RO-Jett, and I think the 140 and 144 are about as good, and the 136 less desirable, although still good and perfectly usable.

   Same with the crankshaft timing. They started with a special narrow-timed stunt version of the crankshaft, didn't want to have special parts for the low-volume stunt engine, and tried one from a QM40 RC racing engine - and it ran better and smoother.
   
 The bar-stock version runs different than the cast case, and there is one additional feature that makes it run different that I decline to mention.

   All this goes to the discussion above - physics is real and magic and mysticism is not real. That's surprisingly hard for stunt people to grasp, or, they hang on to something that seems like "engineering" like the exhaust duration, then treat that like it's magic and ignore everything else. And, most of them have *no idea whatsoever* what they really need to successfully fly stunt in the year 20189, and steadfastly refuse to listen to anything else, to a fault in many cases.

 The same principle also suggests that the ST x45 has similar characteristics, but that is rather a moot point when anyone can probably get an infinite supply of PA40/51/61/65s, OS40/46VFs, that are probably rusting on a shelf in someone's garage, or RO-Jetts made to order in two weeks in any configuration (but get the "Brett" version) . Or a K77, PA75, or a Plettenburg and Axi. There is also no guarantee that the different thermal characteristics (that also matter) are the same, so with a ST X45, you are setting yourself on a two-year quest to figure out exactly what you need, when you can take any of the others and stick it in an airplane and have nationals-class runs this weekend. And the X45 appears to have have been discontinued for years, too, and are much harder to find, parts are close to non-existent, etc.

     Brett

And this is why I snap up VF's whenever I see them. The big problem I forsee in the future is finding light pipes and long enough headers.

[Ruslan Kurenkov]

Hi Ruslan,

Any kind of scavenging can benefit from a tuned exhaust system, so you don't have to worry about that. Schnürle is just more efficient and inherently less stable, and it benefits more from the stabilizing/regulating effect of pipe.
I think the easiest way to start would be to get a correct size pipe and find somewhere the pipe lenght chart (by Randy Smith?) and set all up according to it.
The parameters in the chart are exhaust duration in degrees and target rpm. Using them you set up the theoretical pipe lenght to start with.
Be prepared for increased fuel consumption.

Cheers, Lauri

Hi Lauri
Thank you for participating in the discussion of my future project about installing our Ukrainian engine Stalker 76 RE (with rear exhaust) - American tuned exhaust system, which will regulate the maximum and minimum engine speed. I'll take your advice on changing the volume of the fuel tank.
  How do I solder a new tank? What should be its volume?
Regards,Ruslan

Just to add to Brett’s historical comments ….. I had some beautiful runs with a piped ST60 back in the early days of pipes.  The key word in the previous sentence is “SOME”.  Every now and then it gave a beautiful and powerful lower rpm flight.  But most of the time it was unpredictable.  The problem as I later decided, having gained more tuned pipe experience, was the less than perfect connection of the pipe header to the engine.  The limited engine case area of the side exhaust engine makes a good tight connection very difficult, and any loss of the pressure of the exhaust pulse at this early connection is very destructive to proper pipe operation.  I had one of the early Stalker 61’s that came into the country and eventually did play with pipes on it.  This early version had the slip-on O-ring connection at the engine to header.  I’m glad to see that later motors now have a flanged bolt-on fitting.  Make sure you have a leak proof seal at this joint and you will have no problems running the motor with a pipe.

Hello Frank
Thanks for the interesting information. Please write your results using the resonant tube on Stalker 61. How did the system work?
We really changed now the mounting of the muffler to the engine crankcase. Rubber pads quickly collapsed. Now we fasten the silencer with stainless steel bolts (this is important, black, red-hot bolts are destroyed) and have ceased to use gaskets that were constantly torn when opened during dismantling. Now we use only automotive sealant for engine repair, which we apply with a thin layer of 0.015 inches and immediately clamp the bolts. Before installing the muffler, put a little thread lock on the bolts. This connection works without problems the whole season - 300-400 flights.
Regards,Ruslan

To understand how pipes work, read the pipe section in "Two stroke tuner's handbook", you can find it in pdf form via Google.
Note that they are trying to increase power, but the principles are well explained.
https://www.google.ca/search?source=hp&ei=yRJJXJewO8-c5wLK27P4Bg&q=two+stroke+tuners+handbook&oq=two+stroke+tuners+&gs_l=psy-ab.1.0.35i39j0l2j0i22i30l4.1294.4647..7616...0.0..0.279.2716.2j15j2......0....1..gws-wiz.....0..0i131j0i131i67j0i67.relxv4dC29A

Randy Smiths Pipe chart is a good starting point. The math is all simple linear relationships, so you can interpolate/extrapolate as you see fit for different RPMs and exhaust duration.

http://www.clstunt.com/PipChart.htm

Pat MacKenzie

Hello Pat
I am very carefully studying the information about the systems configured exhaust two-stroke engines that you gave me. thank
Also, thank you for the table for calculating the parameters of the resonant tube from Randy Smith.
Thank you very much Randy for your work !!!
I will use these parameters to calculate the size of the resonant tube for my Stalker 76 PE with an exhaust of 135 degrees.
Regards,Ruslan

The RACING High R.P.M. motors have the 160 exhaust timing .

( Incidently the Ducted Fan motors have wide ' seperation ' Sometimes . Low Trans - High Ex . Like K&B 7.5 D.F. .  )

The HELICOPTER Motors have timing for ' Good pick - up ' ( Throttle up & down well ) Tho the FSR 45 is same as R C FSR 45 . 

Not a pipe man ( Smoke Rollies  ) But Cylinder Port Timing appears relaTED TO RPM'S . AS MUCH AS ANYTHING .

 A LOW R.P.M. Pipe Motor . one would think , would still have Low Timing .

The ' Blow Down ' Figure , again-at least on Racing Motors , is critical & essential to pipe function .
The ' back pulse ' has nowhere to ' trap ' the charge if sleeve timings symetrical  ( Same Trans & Ex - like Std. G-15 136/138 sleeve )

So appears you need maybe more blowdown . At least rather than less .
I think Al Rabes ST 46 bored and stroked to 60 , ended up at 109 Ex 90 Trans . Tho unpiped - obviously .

A few ' extreme ' experiments , at the edges of the logical theories / parameters - if they work at all,
may well define characteriastics AT the alternative biases . To get some ground knowledge .

Anyway . 20 degree blowdown would make sense . for a start .

Hi Matt
How are you?
I see from your knowledge that on the other end of the World, too, use customized exhaust systems?
Thank you.
Regards,Ruslan

[M Spencer]

I see from your knowledge that on the other end of the World, too, use customized exhaust systems?

YES .





Comes ' on the pipe ' at 7-200 - 7-300 .    Runs thru to 8100 . Settled in top will run out to valve float at 8500 .

  Thats ' John the Hippie ' ! a Forester .  On the way to see Bob Dylan. We wont mention the Chain Guard .
Intresting you could anchor up H A R D at 60 , with the left peg near dragging . Blind corner and a logging truck at 10 mph
ahead on the hill .
His first pillion trip . " Just look over my shoulder INSIDE the turn . Lived way out on the gravel by the lakes . Helmets actually BLUE.

Where were we . 27 1/2 Valve Face to end . 1 3/4 o.d. Pluss Wassel Megas . Full length perforated tube baffle . Goes Incandescent .
Cut up the top too , a few inches . To tuck them up & in  .

the Norton Below ran the same pipes ( Mufflers !  ) smaller dia. headers. 72 PR 5 speed . Had the legs on his Brothers
SS 750 Blue Frame dew cati , top end and acceleration .. Wonders what 600 bucks would do for you back then . Mid 70s .
Two P U Bonnies for $ 300 . A T120 Manx for 600. Make ya weep . All the butchered stuff on ebay . 

Yellow Peril was alledgedly timed at 160 on methanol .



Er , that was wot you meant. wasn it .

No worries Brett .  Super tigres on the Brain . wont be piped . Be in the air now bar its 21-46 bolt pattern mount , Not the OS pattern .
After the cycles ones thinking COMBAT theyre using Ferraris for Demo derbies . As it were , with their 21/35s . 
Actually . Now Ferraris ARE mass production , you could use them for demo derbis . Like the Japs . 



 

[Ruslan Kurenkov]

Without going into a complete analysis, I will just say, Ruslan, that I really like what you guys are doing. I once described the Yatsenko similar approach as "an ST60 developed by qualified aerospace engineers".

  Please understand that I am not in any way attempting to discourage you from pursuing this line or reasoning, I am actually fascinated by it. Anything I say on the topic is intended to assist if possible.

    I think I would summarize my point as - we crossed the threshold from not having enough power and working to optimize the output, to having far more power than we could possibly use, almost 40 years ago. But the airplane takes the same .4-.5 HP it always has. The problem has shifted from trying to get more to trying to control what we have in a functional way. Both additional regulating features on the engines, and determining an optimum way of using the prop to dump the power in level flight and still have it become useful in the maneuvers. I posit that prop efficiency is your enemy, if you have way more power than you can use, hooking it up to the air more efficiently is the last thing you want to do. It also seems to mean that you don't need any power boosters on the engine itself, you need a regulator (and a very fast-acting regulator) that you can easily adjust.

   However you accomplish it, I think the two key ideas - you need to control the power from the engine much better than we used to, and we need to try to figure out a way to dump the excess power in level flight - are what we have discovered with the very extensive development we have undergone.

  I would also add that I was not actually responsible for any of these ideas - they evolved mostly by trial-and-error by other people with the drive and the willingness to try new things, whether they had a full picture of why it worked or what exactly they were doing in an engineering sense. My sole contribution, if any, was trying to figure out why it works, and telling people about it.

     Brett

Hello Brett
It was very nice to read your message. You have written everything very intelligibly and clearly, and the most important thing is that with love for the sport and from a pure heart. If aeronautical modeling were taught at the Massachusetts Institute of Technology, then I’m 100% sure that you would be the best teacher. Thank !
I have a few questions for you:
1. How do you solve the problem of the rear center of gravity of your aircraft when you perform the latest pieces of the aerobatic complex?
2. How effective is an engine with a tuned exhaust and a propeller of smaller diameter (smaller than ours) performs the role of an aerodynamic brake to reduce the vertical speed when flying to the bottom in the first figure of the "double coup" complex and in the hourglass figure between the third and fourth by turning?
3. Why do you use fuel with nitromethane for very powerful PA-75 engines?
4. According to Randy Smith’s resonance tube design table for my Stalker 76 with an exhaust phase of 135 degrees, should I use a 18-inch pipe and three-fourths of an inch for 9000 turns? It is right? Is the length of the pipe the distance from the center of the piston to the pre-wall?
Regards,Ruslan

[EricV]

Just to add to Brett’s historical comments ….. I had some beautiful runs with a piped ST60 back in the early days of pipes.  The key word in the previous sentence is “SOME”.  Every now and then it gave a beautiful and powerful lower rpm flight.  But most of the time it was unpredictable.  The problem as I later decided, having gained more tuned pipe experience, was the less than perfect connection of the pipe header to the engine.  The limited engine case area of the side exhaust engine makes a good tight connection very difficult, and any loss of the pressure of the exhaust pulse at this early connection is very destructive to proper pipe operation.  I had one of the early Stalker 61’s that came into the country and eventually did play with pipes on it.  This early version had the slip-on O-ring connection at the engine to header.  I’m glad to see that later motors now have a flanged bolt-on fitting.  Make sure you have a leak proof seal at this joint and you will have no problems running the motor with a pipe.

I would add to your comment Frank, that my gut feeling is using one of Brian's aftermarket ABC P/L sets in your ST60 (along with a better header seal) would also help yield very consistent good piped runs, with ST60 rings being what they were.
EricV

[Ruslan Kurenkov]

Hello, friends !
Today we will publish for you all the basic dimensions of our engines with the location of the exhaust back. We know how important the installation dimensions are when building and designing your new aircraft. This list of sizes will allow you to make the right choice of engine for your aircraft. A little later, we will publish the size of our engines with exhaust in the side.
We wish you many good flights on our lines and our engines.
https://drive.google.com/open?id=1yrdq6R8i03Jdesvh9ZYcst3K-cWFMoKc
Regards
team controllineparts

[Ruslan Kurenkov]

Hello, friends !
Today I measured all sizes on Stalker engines with exhaust to the side, and transferred to paper. These are just 3 engines. I think my work will help someone.

https://drive.google.com/drive/folders/1C36AUy_IpyScfk279qEJ8Oz9_rlQsn9O?usp=sharing

Wishing you a good flight!

[John Lindberg]

My OS 40VF ($135.00 off Ebay, NIB) has been running now for probably 5 years, runs like a top, uses, as Brett said, about 4.5 ounces of 10% fuel. I had it in a overweight Impact (73 ounces, ouch!) that little engine hauled it around real good, no problem!   

[Brian Gardner]

Just a reminder to my fellow Aussies that I'm still the Stalker dealer here.

Brian

[pmackenzie]

My OS 40VF ($135.00 off Ebay, NIB) has been running now for probably 5 years, runs like a top, uses, as Brett said, about 4.5 ounces of 10% fuel. I had it in a overweight Impact (73 ounces, ouch!) that little engine hauled it around real good, no problem!   

And your point is?

Good example of thread crapping 

[Target]

My OS 40VF ($135.00 off Ebay, NIB) has been running now for probably 5 years, runs like a top, uses, as Brett said, about 4.5 ounces of 10% fuel. I had it in a overweight Impact (73 ounces, ouch!) that little engine hauled it around real good, no problem!   

The pipe that (I assume) you are using cost you something though, right? Are you on the first or second pipe? The cost of the pipe brings the cost very close to the cost of a more expensive engine, to be fair, I would think.
Lots of ways to skin the cat it seems. Which makes things nice for us.

R,
Target

[Brett Buck]

The pipe that (I assume) you are using cost you something though, right? Are you on the first or second pipe? The cost of the pipe brings the cost very close to the cost of a more expensive engine, to be fair, I would think.

     For fear of incensing Pat further, you need a pipe for the more expensive engine, too, so a $450 engine $125 is still more expensive than $125 engine with a $125 pipe. The fact that the $125 engine also runs better than many of the $450 engines helps, too.

    All of this cost is in the noise for the competitors, *travel cost* is by far the most expensive element. Your engine is going to last 10 years, $450 might be one weekend worth of gas/hotel bills.

    Brett

[John Lindberg]

As far as the pipe goes, I already had a brand new 60-size Randy Smith pipe I bought along with a PA 51 in 2005. I had the PA 51 in a scratch built Staris, ran it with a header muffler set-up, which was popular in my club at the time. The remains of the Staris can be seen in the 2017-3, page 1 of Stunt News. It's in the upper right hand corner. Also, you can see it on page 65. Scott Richlen, a member of our club, thinks it's funny to print it. Brett is right, even the rooms at the "Blue Mountain hotel" have gone up, the stoop leading to the front door of each room (all ten of them) was a cinder block. It's on John Brodak's list of "Accommodations in Uniontown"- the birthplace of George C. Marshall. There is a tall office building downtown with a large mural of Marshall painted on it. "Fracking" has caused vacancy's in the area to disappear! Still running the same pipe, runs great! Got it in a Randy Smith "Satona"-nice plane!

[Target]

None of the Stalker engines listed are $450.
40-46 are 250 or less.
51-66 are 300 or less.
76-18 are 360 and 380.

Thank John for reporting on the longevety of the tuned pipe, that is good to know for sure

[John Lindberg]

I'm hardly an "expurt" on pipes, used some when I flew R/C, the metal ones, they were noisy! The Randy pipe works, the VF 40 has quite a lot of power with it. Set it up like Brett posted on Stuka Stunt a number of years ago. It's all paid for! 

[Scott Richlen]

The remains of the Staris can be seen in the 2017-3, page 1 of Stunt News. It's in the upper right hand corner. Also, you can see it on page 65. Scott Richlen, a member of our club, thinks it's funny to print it.

Nope, not funny.  Why do people watch NASCAR?  The tension is the big car wreck.  What's the tension of PA or any stunt event?  The big crash!  It's a key ingredient of the excitement of watching really good PA.  When someone has a low pull-out you can hear everyone go "Oooooh!"

Why is RC so boring?  Because it is way up in the sky, no danger there!  Why is YouTube RC fun to watch?  Why, it's always of crash compilations!

John: send me some more pictures of your crashes.  How about your Impacts' impact?  I'll stick them in Stunt News.  You'll be famous!!

[John Lindberg]

The Impact is still in one piece! No one to watch my flights at the flying circle!

[Scott Richlen]

Oh-oh.  So, your Impact never impacted?

It must have been your Thunder-Gazer that decided to do some Thunder-Grazing.....

Send those pictures and I'll get them into Stunt News.....maybe we can do a special issue: "Ka-pow!  The many former models of John Lindberg and their short, dramatic life."  You'll be more famous than Brett! 

[John Lindberg]

No more pictures! The Thunder gazer was 2 years old, the Staris was over 10, the Impact is appx. 5 years old! 

[Don Jenkins]

Hello, friends !
Congratulations on your upcoming New Year!
I want to wish you all a good mood and a lot of good flights in 2019.
Controllineparts will do its best to ensure that your flights on our lines and engines are successful and bring you only positive emotions.
I want to invite you to discuss all questions about the use of different Stalker stunt engines in this particular special topic.
I want to invite you to ask here any questions on the selection of the stunt engine for your aircraft, on the technical parameters and installation sizes of various Stalker engines, on installing the correct propeller size on your engine and on the fuel composition, on using the correct type of glow plugs and providing spare parts.
I will be happy to answer all your questions and will gladly take part in the discussion of all issues related to the repair and maintenance of the stunt engine Stalker.
Today we have in stock more than 10 Stalker, varying in size and location of the engine muffler, from the smallest 0.40 to the most powerful 0.81. I think that such a wide range of stunt engines will be able to satisfy both the novice and professional pilot. We also provide full technical support to our customers and the provision of any spare parts for our engines.

Regards
Ruslan Kurenkov

Ruslan,

I mounted my Stalker .61 inverted and had no issues.  I recently heard the .66 has trouble running inverted and the fix is to mount it horizontal or at 220 degrees.  Any thoughts or comments?

Don

[Ruslan Kurenkov]

Hello, Don.
Engine Stalker 61 and Stalker 66 are exactly the same in operation and adjustment engines with the same installation and dimensions.
On my plane, 5 years ago, the Stalker 66 engine was installed horizontally (270 degrees) when looking at the plane from the front. The engine worked perfectly, for 2 years I made 800 flights. Parallel with me on the same airfield our junior Kucher Nikolay (3rd place in the World Championship 2018) trained on the Stalker 66 which I installed him with the cylinder down (it is 180 degrees when viewed from the front). For three years he made 1500 flights on this plane and on this engine and became a three-time champion of Ukraine among juniors in the class F2B. I personally attended half of these flights. The engine worked fine, but only under certain conditions.
1. Turns on the earth - 7800 ob.min. (for this you need to use a propeller of 350mm by 160mm), the speed of a circle is 5.3 seconds on lines of 65 feet.
2. The glow plug is only hot (we use OS MAX A3, No. 6, Hot) - if the engine rpm is 7500 rpm in cold weather and you install a cold glow plug, for example OS MAX No. 8, then at the location of the cylinder down vertically there may be problems with the engine choking at sharp corners.
3. The amount of engine oil in the fuel - no more than 16 percent. (8 percent - castor and 8 percent - synthetic). At low revs - 7500, in the cold, and with a lubricant content of more than 20 percent, the engine can also sometimes be choked by a large amount of oil falling on a cold glow plug. I had it once when I installed a cold glow plug (Cold) and added castor oil up to 20 percent (without synthetics). My motor, which was mounted 270 degrees to the side of the cylinder -
 has stopped. As you can see when mistreating the engine, it does not matter how it is installed.
The best location of the engine is 225 degrees at the sight of the previous one. It is not in the side and not down - it is in the middle between them. With this arrangement, the engine works perfectly everywhere and best of all - at the top, above 45 degrees, on the figure "eight overhead". With this arrangement, the engine is very convenient silencer goes under the fuel tank.
Regards
Ruslan Kurenkov

[Guy Markham]

Please show picture of engine   "225 degrees" with engine silencer under fuel tank . Thanks.

[Scott Richlen]

That's a good-looking wood 3-blade.  Who makes those?

[Perry Rose]

What about mounting the engine at 90 degrees or 135 degrees??

[Ruslan Kurenkov]

Please show picture of engine   "225 degrees" with engine silencer under fuel tank . Thanks.

Hello Guy
Here is a photo of my aircraft with a Stalker 76 engine with a cylinder angle of 225.
On the previous plane, my Stalker 66 was set to cylinder 270.
Regards,Ruslan

..not Stalker but this is what Ruslan means.. L

Thanks Lauri!
I had just such an arrangement of the engine, as on your plane.
You should definitely try to fly on Stalker !!!
Regards,Ruslan

[Ruslan Kurenkov]

Hello, friends !
Today I present to you our new CNC wooden propeller for the classic 4-2-4 Stalker 61 aerobatic engine. Many pilots have been using the Stalker 60 or Stalker 61 for a long time. We are happy to fulfill their wishes, and have started serial production of size 61 air propellers (9.95 see cube). The propeller is designed exclusively for Stalker sizes 60 or 61. Before production, the propeller was tested and was changed many times. As for Stalker 76 and 66, the propeller size 60 - 61 is also made of birch or beech, and after manual adjustment of the screw pitch and balancing, it is painted with automotive two-component acrylic clear varnish or white automotive two-component acrylic enamel. As on previous Stalker series propellers, the pitch of the screw has a non-constant size, it decreases from 170 mm to 140 mm. The screw pitch at 75 percent of the axis of rotation is 160 mm. The final finishing of the wooden surface of the propeller, the pitch of the blades, balancing, preparation for painting and painting by airbrush is done exclusively by hand, with great love for sports and for the athletes who will use the propeller.
This is a basic requirement for the production of all our products.
I wish you all a lot of good flights and good mood! 
https://controllineparts.com/stalker/192-propeller-60-61-stalker-stunt-engine.html
Regards
Ruslan Kurenkov