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Experiments in hope of extreme power...

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Experiments in hope of extreme power...

Post  Paulgibeault on Thu May 31, 2018 1:07 pm

Hi Guys,

Some of you know that I have been using a Shuriken engine to power my 1/2A profile protospeed model. The Shuriken is a quite old, out of production engine that has not been made or supported for many years now. I figured that until I broke it, it was still useful to play around with. I accidentally acquired aluminum and a ceramic coated cylinder liners in an Ebay acquisition of (mostly no good) parts.
The originally designed cylinder/liner assembly started out being made from Iron (piston) & steel ( cyl. liner). I don't know if many of these were made, but I have one.
Although it's WAY better than it's TeeDee rival, with a wrist pin rather than a ball-socket joint, it was not at all optimal for the time.

The next step was to go to a much lighter aluminum piston and run it in a chromed brass cylinder. Known as ABC. The next advance was to run an aluminum piston in a chromed Aluminum liner, that if nothing else yielded a lighter engine. Known as AAC (and boy the sturdy Shuriken is relatively heavy). The final stage of design yielded a Ceramic coated aluminum liner using an aluminum piston. This was known as AAO.  Ceramic feels kind of slick, not quite that of teflon. Teflon coated pistons and parts have been used successfully in high performance model engines, but were not ever featured on any 1/2A production engine (other than Norvel) that I'm aware of. Engine modifiers generally sent out parts to a shop for coating, which would then require a re-fit in order to get them back into the engine. If fitted incorrectly, they worked poorly. I never came across published data on this coating procedure, so those that tried these things were truly pioneers, going out on a limb & often ruining parts and engines...
Nonetheless, in the quest for the holy grail of speed, failures are often expected along the journey. If not expected, they'll happen anyways!

I personally never tried the Iron/Steel combo because I knew the ABC was superior. That being said there was a great variance in the performance of my ABC piston/cylinder units. The reason being is that several cylinders had different porting (my parts were experiments by somebody). But, more importantly the fit and profile of the cylinders were different. With the  tolerances in the tenth of a thou. (or less) I didn't have the instruments (+ knowledge of use) to do consistent measurements.

So I reverted to the tried and try "cut and try" method. Essentially meaning run the combo's & see what works best. In the end, I had my friend from California & master modeller John McCollum custom build be a few (one off) ABC piston / cylinder sets. Because John KNOWS the proper tapers + used a superior German Mahle ( high silicon alloy) aluminum for his pistons, his sets turned out to be the very best performers, even with MUCH less radical porting. The difference between best & worst being about 4,000 RPM!! ( 29,000 -> 33,000).  It's hard to call a 29,000 RPM .049 a failure, but it really is when compared to a 33,000+ RPM engine. The inflight difference being ~ 20 MPH!!  
At the end of the bench testing day, the promising Ceramic cylinder was a failure ( at 31,000 RPM), but it could very well be because the critical "fit" is off, not necessarily because of the Ceramic itself.  Or maybe it is the Ceramic...?? I don't really know much anything other than what my trusty tach tells me.  There are other maddening issues like bad / semi-failed bearings that have interfered with what might have been a superior result. Sadly, with no spares or spares with quality...my research is stopped for the time being.  BTW, DO NOT tell me to use Boca Bearings, because that's a route to very bad results....ask me how I know?  

I'll add photos later when I return from an appointment...

Cheer,

Paul


Last edited by Paulgibeault on Thu May 31, 2018 1:09 pm; edited 2 times in total (Reason for editing : Grammar)
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Re: Experiments in hope of extreme power...

Post  fredvon4 on Thu May 31, 2018 2:06 pm

Paul I hope they have your medical issues sorted out.... I follow your musing on Flying lines

I often wonder in your testing how much credence you give to various fuels more to the point the oils

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Re: Experiments in hope of extreme power...

Post  1/2A Nut on Thu May 31, 2018 2:37 pm

What prop used for the tests?

Here is my Picco with a Profi .8cc tuned pipe for reference:



Published on Feb 25, 2017
Custom Crank / Picco .0519 ci / .85 cc / APC 4.2x4 / 29,473 rpm
Custom crank for improved longevity and performance.
165 deg exhaust over stock @ 160 / 4oz break in time results:
Static: 12 oz thrust / 111.3 mph / .227 hp / 170 W

Brief peak needle 30,564 rpm
Static: 13.4 oz thrust / 116 mph  / .255 hp / 190.2W
34W improvement over stock crank. Thank you Mel!

165 deg timing / 9in MRP
30% nitro / 20% oil / AP .09 carb / Profi .8cc Tuned Pipe

My CS RC with a Profi pipe (bit loaded down) it's the flight prop not so good
for bench testing really needs the 4.2x4 for that.



Published on Nov 24, 2017
CS .061 / Nelson Plug Med. / Profi .8cc Tuned Pipe / APC 4.5x4
Best Peak 25,193 rpm / .188hp / 140.3w / 12oz thrust / 96 mph
Hold peak 25,052 rpm / 25% nitro / 20% oil blend
8.75" Mean Reflective Point / "center of piston to 2" from end of stinger.
Needle Valve 3.75 turns out due to no pressure taps.
105.7g as shown with pipe
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Re: Experiments in hope of extreme power...

Post  roddie on Thu May 31, 2018 9:46 pm

VERY interesting stuff Paul! Thanks for sharing your experience with us here.
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Re: Experiments in hope of extreme power...

Post  gkamysz on Fri Jun 01, 2018 8:24 am

What size are the bearings that they are difficult to source? Developing piston and liner is a lot of work, and certainly many things need to be measured very accurately to prove a design. Did you make the AAO sets? It's truly amazing that you can see a 4kRPM difference between liners sets if the porting is otherwise the same. This represents 45% more power at 33k, vs 29k. Are people running Fora or similar?

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Re: Experiments in hope of extreme power...

Post  ticomareado on Fri Jun 01, 2018 11:44 am

Wow. Kind of reminds me of a pack of crotch rockets at 2 AM on the Interstate that sometimes wake me up when there are no leaves on the trees and its warm enough for that crowd to get out for a little highway to hell ridin'.

Question about these demons:

If, say for example, a typical Black Widow will run 3.5 minutes on its 8ccs of 15% nitro fuel, about how long will one of these demons run on 8ccs of whatever it is they're burning?
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Re: Experiments in hope of extreme power...

Post  Paulgibeault on Fri Jun 01, 2018 2:25 pm

HI Fred, and thanks for the nice wishes, much appreciated!

In AMA 1/2A speed & 1/2A Profile Proto events, I give NO credence to the fuels because they are mandated 10% nitro, 20% oil (50% castor - 50% synthetic often Klotz), the rest is methanol. The fuel is always supplied by the contest management, case closed.

In the old days before the mandated fuel came into effect, THAT was a whole different story! People (including me) used extreme (72-78% nitro) no alcohol & sometimes turbine oil (Mobil Jet II) was blended in. THAT was very potent fuel & gave enormous power over the standard.  It ate glow plugs. Fortunately, we haven't had to play "chemist" in C/L speed for many years now & I don't mind that part one single bit. Smile

Cheers, Paul

p.s. My Shuriken was indeed designed to handle all the nitro you could possibly use in it...

fredvon4 wrote:Paul I hope they have your medical issues sorted out.... I follow your musing on Flying lines

I often wonder in your testing how much credence you give to various fuels   more to the point the oils

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Re: Experiments in hope of extreme power...

Post  Paulgibeault on Fri Jun 01, 2018 2:41 pm

HI Brad,

My reference standard prop for AMA 1/2A Proto is the:  APC 4.2D X 4P nylon. Far too small for Cox engines, but excellent for Protospeed & Class II mouse race.

This prop I believe is too big for a piped engine on the ground. Perhaps trimming the diameter somewhat or using the APC 4.2 X 2P is better for that purpose.
Thank you for posting your Picco stuff....very interesting. Do you use a Galbreath de-stroked Picco or do you leave it the normal .061 (1cc) size?? The 1cc
size certainly has more power hands down.  That being said, so far only Jerry Rocha of Napa has been able to extract the power necessary from a Picco to exceed the normal 85 mph. Jerry's best is 111mph & I flew that model for him. Wowza! At 4.4 ounces it takes off like a rocket & is too fast for all but the most experienced pilots! What a blast it is flying for Jerry!
Cheers, Paul

1/2A Nut wrote:What prop used for the tests?
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Re: Experiments in hope of extreme power...

Post  1/2A Nut on Fri Jun 01, 2018 3:39 pm

Paul it would be a treat to see some vid of that action!

The engine is stock all but the crank / known to be brittle and snap in short order.
Not a Galbreath de-stroked Picco, Mel made two for me aka "Toad" on RCG / RCU.
The stock engine is .0519 ci / .85 cc.

Here is the Picco in action hits 50K ish on the bench prior to launch:



Published on Nov 22, 2016
Picco P-Zero .05 / .85cc engine 2nd Vid - Cut Octura to 1426 detongued
Static rpm on the bench hit tad over 50,000 rpm.
RPM higher than the stock X427 prop, best pass 36,902 rpm
Med lift prop. 30% nitro / 20% castor. Best pass 43 mph.


I cut down the dia. and backcut on the blades of APC props for the TD .05
so far this is the best results getting brief peak down wind passes by the cam.



NANO III / 9oz / 28" span / APC 4.22x5.5
Best pass 26,647 rpm / 139 mph prop speed
Static 20,370 rpm / 1oz fuel / 25% nitro / 20 castor
With speed, the sound follows behind the plane neat effect.
Checked all passes found the best per posted vid:
Per Audio RPM Gauge 26,647
Per Prop Calc 139 mph
Per Doppler Wav. Scope software 136 mph / 219 Kp/h

Another surprising engine was the Fuji .05 shown here:



Published on Jul 24, 2016
Best pass 36,747 rpm gives a theoretical prop pitch speed of 157mph potential from a HQ carbon / nylon 4x4.5 prop
per audio tach from brief bursts of rpm past camera. With the right size plane the prop speed can be used to it's full advantage.

Per Doppler wave analysis: 238 kmh / 147.89 mph best pass.
Down wind shallow dives gets the rpm / speed up, prop is too small into the wind or when pushed
in steady banking turns. Peak speed in front of the cam is brief average speeds much lower.
Wing is approx 130sq. in. meant for a TD .09 this was just a way to test the engine out
and observe plane is too big for the engine.
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Re: Experiments in hope of extreme power...

Post  Paulgibeault on Mon Jun 04, 2018 2:01 pm

Ti,
If you can get 3.5 minutes from a Black Widow you truly have one economical engine! With 25% nitro & stock vents 90 secs to 2:30 (flight time) is about the best I see with the stock .082 tank venturi. True, the small Silver Bee / Golden Bee ?? .062" venturi tanks can give slightly over 3 minutes of run time.  I can't answer your question about exactly how long (time wise) my engines run. My range is from 90 seconds to 2:10 sec. on the test stand with engine sideways (pick up at bottom).

What I do know is my flight testing showed that the LAP RANGE on my mouse racer INCREASED the more nitro I added. So if I had an engine that was a bit short on range (say 32-34 laps) with 40% nitro, going to 65% nitro increased the range to 36-40 laps at a faster speed.

Cheers, Paul

ticomareado wrote:
Question about these demons:
If, say for example, a typical Black Widow will run 3.5 minutes on its 8ccs of 15% nitro fuel, about how long will one of these demons run on 8ccs of whatever it is they're burning?
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Re: Experiments in hope of extreme power...

Post  GallopingGhostler on Mon Jun 04, 2018 2:10 pm

Paulgibeault wrote:True, the small Silver Bee / Golden Bee ?? .062" venturi tanks can give slightly over 3 minutes of run time.
Sounds about right, IIRC, back in the late 1970's I was getting around that with my stock Golden Bee on standard 25% nitro fuel. This was on a Q-Tee flown single channel (elevator was fix wired through an adjustable RC clevis allowing trim adjustments for flight), 5.25x4 to 6x3 props and Ace RC exhaust sleeve throttle.
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In search of Extreme power...

Post  Paulgibeault on Mon Jun 04, 2018 3:17 pm

Here are some photos that show the "evolution" of piston / cylinder technology experiments. It was most lucky that the piston from my best ABC assembly just happened to fit well (or as well as I think it should) right into the ceramic cyl liner. Sadly it was several thousand rpm short of best...even though if you see the photos, the cermanic liner cutouts are radical, and go completely through the cylinder as per original design. My custom ABC liners are not radically cut that way, because it's impossible to control cylinder roundness with a cylinder cut that way. I think roundness + correct taper in a cylinder, trumps porting every time...So far, that holds true.

Also of note is the late Chuck Schuette designed head with was designed to take the excellent Novarossi tapered seat glow plugs. It works well, but is just short of the one piece Norvel Spiralite speed plug, which although does not last very long (1 per flight), still gives the highest performance so far... This is acceptable for C/L speed, but lousy for most other applications.

Note:  That pink tubing is actually bladder tubing that I use for my tests as my engine is pressure fed.





Last edited by Paulgibeault on Mon Jun 04, 2018 3:27 pm; edited 5 times in total (Reason for editing : add'i info added)
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Re: Experiments in hope of extreme power...

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