Pond Skipper

CS .061 RC Engine / Bearings / Tuned Pipe

I bought this one off ebay for 43 bucks never ran new in the box. Comes with a blank spinner for single or 2 bladed use - so cut slots and mounted a APC 4.2 x 4. Is this prop par for the course for this type of engine or should I jump up to a 5 x 4 since its a .061??

The engine is rated to run up to 38K as the RC version. I doubt it will run that fast on 2 blades let alone last long if I set it up to run at high rpm's - so not sure if the APC 4.2 x 4 is the right prop if I want to keep it tame enough to last. I will be happy at 32k /121.2 mph theoretical speed.

If anyone has owned or owns one please chime in. I would imagine I will be using 25% nitro for the first flights and have a jug of 40% for a 4ch plane weight around 10-12oz. 80-100 SQ/IN. I want a mix of speed and acro flying with it. I have a Mack pipe made for .09 - .015 size engines. I will try it as is get a tach reading then trim it down till it peaks out. I would imagine I will end up cutting as much as 2in off to compensate. Any insights would be appreciated.

Pond Skipper

Also is there a nelson plug conversion out there for a threaded button plug? I want to be able to swap out threaded plugs in the field.

combatpigg

My Feedback: (3)

The 4.2 x 4 is "The Prop" unless you want to run custom made. I ended up shaving the blades a bit thinner to help with heat issues.
Does this engine have 180 degree [or more] of exhaust timing...? [There is also a lower, "sport" timed version.]
Either Bill Hughes or Doug Galbreath might know about Nelson heads. Bill is the US distributor of G&Z [almost the same as CS].
There is also a C/L Speed forum at Delphi Forums where several flyers with lots of experience hang out.
They can give you specifics down to the ,001" about how to be successful. In a nut shell, you want to start the tuning process from the under compressed and under propped side of the equation and your goal is to get great runs without generating too much heat. You'll melt out the silicone pipe seals and melt the epoxy insulators right out of the glow plugs if your set up is too aggressive. The wrist pin circlips de-temper from hot runs and wedge themselves between the piston and liner.
This sort of stuff is avoidable if you know how to proceed with caution. Knowing how to set a needle and mix a batch of 75 / 25 fuel is not enough. Being able to control the mixture in flight would be a tremendous advantage, plus you can abort a bad run ASAP.

Pond Skipper

Thank you CP

They made two versions in this class the CL Race and RC Race both have a long exhaust timing and need pipes to run right.

I do have the specs on the CL:

Exhaust - 182 deg.
Transfer - 130 "
Intake - 178 "

Stroke is 10 mm
CS .061 (1.0 cm³)
Manufactured in 1994
Another engine «Made in China» but probably not suited for the everyday user. This is a really hot racing engine for small control line speed models. It is intended to be mounted on an aluminum speed pan and to drive a single bladed carbon fiber propeller. Due to the long exhaust timing, the engine relies on the nice tuned pipe to run properly.

Pond Skipper

I did a search and found:

B & L HOBBY SUPPLIES, INC
113 North Chase Ave., Bartlett, IL 60103
G/Z .049/.061 Engines; sales, service & parts.
Engines available in both normal and pipe timed configurations. (Bill Hughes)
e-mail: [email protected] 630-736-6036

DOUG GALBREATH
3408 Topsail Place
Davis, CA 95616
Cyclon .049, Nelson 65 and Audio Tachs
(Doug Gailbreath) 530-757-6058

Here is what I had read lucky for me I have a throttle to avoid abusing the top end so will just be happy keeping it running in the low 30's.as a anyday flyer.

• .061 GZ. Currently not manufactured but a new run of motors is rumored. This engine is very fast, but quality is a crap- shoot. Some engines work great while others are junk right out of the box. We have been buying our GZ motors from Bill Hughes at [email protected] .

combatpigg

My Feedback: (3)

You have done your home work..!
Parts fit is so critical that it is not realistic for any mass producer to make every unit a world class engine. If you have access to bins full of parts plus have machinist skills, time to kill and know what feels right...then you can make these engines really scream.
I could tear down the same engine to the bare case and reassemble it with the same parts and get different results every time.
The best one I ever had was a .061 that Bill used at a FAI meet in Germany to place 3rd. That one would rev a 4.2 x 4 to 42,000. It had a Satanic howl to it. It died from too much prop, too much nitro, too much static compression ratio and no way to richen it after it got it's first gulp of air.
At this level of performance, component failure is to be expected but failure can be delayed with cautious use of prop load, compression and nitro %. Bill and the guys at N.A.S.S. have already burned through much time and money playing with these things so if you invest some of your time to pick their brains they can save you some grief.

Pond Skipper

Yes I do plan to play it safe and be happy its a 1/2A running in the low 30s which is leap past most of the engines I have on hand this size. I do have a AME RC carb version of the Norvel and another AME made for the Heli As an option in lieu of the long winded exhaust timing, I wonder if I can get by with a header pipe as by nature the tuned pipe stresses the engine more when on step with the engine. Im not trying to squeeze out rpm and can spare the additional strain on the crank and rod. Heres the pic of the simple header I matched up some metric tubing for a snug fit and coned the tip, should help with some of the noise. Bummer about your engine but wow 42k is screaaming got any of it on vid>?? Looks like I have the full .061 CS collection now.

combatpigg

My Feedback: (3)

If the engine has 180 degrees of exhaust it probably wont have the torque to do much "naturally aspirated".
Just a guess. The static compression for a high timed., piped engine has to be set LOW to compensate for the massive dynamic compression level once the supercharging effect takes place. Dave Shadel recommends starting so low that the engine barely has enough compression to fire up.
For bench running I believe in blasting the engine from the front with a powerful fan. Having a IR measuring instrument is also handy..like what all the RC car guys use. One reason why RC car engines can live a long time at insane revs is because through gearing the engine never sees any load. With speed props the piped engine sees a constant load that can cause a run away heat condition that leads to the chain of events I talked about earlier. So, for my first runs...maybe for ALL runs I would consider the 4.2 x 4 as a slight OVERLOAD. At least until you can prove they can be safely run right out of the package with no heat issues.


There was a video of the G&Z Express posted to RCU many years ago but I've lost track of it. It was posted by a guy named Scudrunner. I think it was called NW 1/2 A Racing..but I don't remember exactly. It wasn't part of a build thread, I think it was a separate post to feature both his and my speedsters. It really had a unique whistle at 700 cycles per second.
I would run it much more intelligently now that I've spent enough money getting a rough education [replacing burned parts]...mainly with Dave Shadel and Henry Nelson as my mentors on how to keep the piped Nelsons alive. Same rules apply to the 1/2 A engines.
The G&Z .061 runs pre-staged still spitting raw fuel at 32,000 and hits the pipe hard [as you lean it] with an additional 10,000 like throwing a light switch. I ran it on bladder, but the high frequency humming would cause the bladders to rotate and pinch themselves off. The humming also chafed the latex and popped them. The best solution is a hard tank and a pressure nipple at the fat part of the pipe. Then the fuel pressure will ramp up based on demand, proportional to demand.

aspeed

I just have the .049 ones. One CS piped, one CS normal, and one GZ normal. The GZ is much slower so far. The pipe I got with it is 10 & 1/8" long with a .222" outlet. The length is adjustable, but not much. I made a head for the Turbo plugs, the Nelson ones are about 1mm larger dia. I just made a 90 degree chamfer from the edge of the plug (.187") out, and then maybe a 2 degree angle to the cyl. bore. 27,000 on that prop on the unpiped one, the GZ 21,000 and I didn't try the piped one yet. You will get ulcers over the needle settings, two turns of the needles usually have no effect, and it can melt down quickly. A small tank is the norm anyway. The CS pic is on the bottom of the pic, it can be compared to the Rossi pipe and the other one which may be the Russian Ucktam .15 pipe. Just a pic I had on file. I started a mold for the Uctam and the CS .049 pipe in case I bent it or something. Lost interest since. No place to fly them on control line, and I can barely keep up/see with my Sig Wonder at maybe 90 mph. Just searched for the GZ Express, nothing http://www.rcuniverse.com/forum/1-2-...-gz-delta.html http://www.rcuniverse.com/forum/1-2-...eed-plane.html

combatpigg

My Feedback: (3)

I was never able to duplicate the same power level as the first engine that was put together by Bill Hughes. I ordered replacement pistons, liners, rods and head buttons for the most part. The bottom ends would get hot enough to discolor the paint on the fuselage but they held up just fine. At 42,000 rpm there was enough humming to cause erosion of aluminum to aluminum contacts that weren't absolutely tight. In some cases, like with the 4 bolt head, you could never get it tight enough. The head buttons need to be a snap in fit to the liner. The engine case can grow away from the liner and cause trouble, too.
The key is being able to control heat.
I see on that old thread I was using 40% nitro...what an IDIOT...!!

aspeed

The little motors run so much better on high nitro, but at what cost? I didn't like when the rules went to 10% nitro, but it is really pretty good. They changed 1/2A last however. They are still pretty fast, and last longer. It just took a couple years to figure out less pitch is the answer, and higher revs unfortunately too. I used 80% nitro for all record attempts, and 40% otherwise. 10% is a good thing IMHO.

Pond Skipper

Thank you great info! I drew up a plane doddle the idea is to stay thin and lanky to get the most out of my rpm. Rolled ply fuse with a carbon tube boom from the trialing edge of the wing back. The wing will be thin ply with a light balsa core at the root about 6in of 3mm carbon tube.

Fuselage wood portion - 25"
Wing 5.25 tapper to 2.25" x 22" for 79.75 Sq/In
Landing gear will be slide in removable for good grass landings other wise will have the gear to save the belly.
Goal is 10oz or less - without the pipe to keep it light
I will go metal gear sevos for this one and coreless motors for elevator / ailerons

I may go with a double lamination of the rolled fuselage and nix the carbon tube first layer thicker than the second.
Or double layer from the firewall an inch or two past the trailing edge of the wing and carbon tube.
I will leave the engine swinging in the breeze to keep it from heating up more than it must.
I may add rudder in lieu of in flight aileron failer and for some acro / taxi - take offs.

Pond Skipper

Here is a pic with the flying feathers I went with swept tips so lost some more sq/in should be very fast at this size I may bump it up to 24in span do to the loss.

combatpigg

My Feedback: (3)

That's a very fast looking birdo...!
If it ends up real-real fast it's nice to have a 1 1/4" tall elevator control horn.
At least that tall.

Pond Skipper

lol Yes I need that vertical control horn for sureeee..

combatpigg

My Feedback: (3)

I'll be surprised if it runs well without the pipe if it has 182 degrees of exhaust..I think 165 degrees is the upper limit without the boost [added torque] of the pipe. It doesn't cost anything to give it a try, though.
I'm just reciting what I believe to be true about exhaust duration. I tried running a Nelson FAI .40 without the pipe for break in and it barely had as much power as a OS .15.

Pond Skipper

Thank you for the tip -If I have to use the pipe this plane design will need a tad more wingspan as the Mac pipe is 41g uncut.
I will settle with a 24in span wing if the bench test yelds less than 28k.

combatpigg

My Feedback: (3)

See what your's can do with the open header and if it seems weak you might find a stack of head shims that can come out. Who knows, there might be a liner shim to be removed too..?
If there is a stack of head shims, get a depth clearance reading with no shims. You can insert a length of 1/16" solder through the glow plug hole until it jams against the cylinder wall, then rotate the engine past TDC. The piston will crush the solder and now you can measure the thickness of the solder to know what your "natural" deck height is with no shims.
It would be handy to have a sport timed P/L set for when you don't want to mess with the pipe.
I'm curious to hear how this runs, especially with a carb.

aspeed

That Mac's pipe may not be what you hope. It is more for an .09 or .15, but you may as well try it, run what you brung. It will likely need at least the tailpipe diameter closed up a bit to get on the pipe easier. You are right, the Mac's pipes are pretty heavy. There may be some other options that will work, check out some 1/16th scale RC car pipes to modify, or CO2 cartridges and different length headers or whatever if your pipe is disappointing. Just to give you some #s, the stock one is 14 g, the ID at the front pipe is .300" and the big dia is around .780". Maybe some thin 3/8th" or 1/2" tubing necked down at the front and rear might give some results.

combatpigg

My Feedback: (3)

The G&Z pipe is made from paper thin material. It is threaded together at the fattest part. I never realized this until after it came apart. Amazing metalsmithing to do such a discreet job of threading sheetmetal pieces together.
I don't know what it weighs but they seem very light.

aspeed

It is a nice piece of work, 14 grams.

Pond Skipper

Thank you gents very good intel!!!


Yea when I bought the pipe I knew it was going to be a stretch for a .061 figured I would be cutting it down some.
ID .2" and .453'' and 9.9" long.
OD at the peak of the cone 1.1"

aspeed

The outlet isn't too bad, it may be fine. I think the stock one was a bit small overall anyway on the diameters-just by the overall look of it. It is only 10 1/8 " long pretty much like yours.

Pond Skipper

Mac pipe was originally designed to be used with a header pipe and a coupler so imagine the overall volume apparently suits its class range.
Hope I can get by with just a header pipe but don't mind lugging around the extra weight if need be to reach 33k in level flight. At that rpm I should
get a nice flying 100mph plane for weekends at my local park there is enough airspace for 1/3rd scale 200+ planes.
In post 7 I show a simple rubber insert I could be close already but imagine I will need to shorten it up. I will bench run with a APC 4.2x2 to set the pipe.
Should be interesting to hear this engine run it turns over with a fast sharp distinct snapping sound unique to any other engine I own.

combatpigg

My Feedback: (3)

Yes, it looks like that pipe could give you what you are looking for and like A Speed mentioned the stinger can be experimented with easily. The Catch 22 with the pipe is the extra drag. You can get an unpiped and very light AME .061 to turn a 4.2 x 4 close to, if not more than 30,000.
The pipe of course muffles the harsh sound VS open exhaust and makes sweet music, plus it's fun / educational, so that's the untangible upside.