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OMG it arrived - Profi speed .049

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OMG it arrived - Profi speed .049

Old 04-19-2015, 10:05 AM
  #51  
Pond Skipper
 
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2.75P / 42k / 109mph
3 / 42 /119
3.5 / 40 / 133
3.5 / 38 / 126
4 / 36 / 136

Last edited by Pond Skipper; 04-19-2015 at 10:56 AM.
Old 04-19-2015, 11:58 AM
  #52  
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I have no intention of flying this prop - it is nothing more than a cooling fan and light shaft load for rich rpms. The 1 blade 1/2A speed props start at 4 pitch and go up to 5. RC models can go faster and unload better on those higher pitches.
Old 04-19-2015, 05:24 PM
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Holy learning curve..

I think I'll redo the tank system "gooder", and drop an RNV in the pipe pressure line so I can get an idea of how big an orifice it should have.

This engine is made like a jewel.. all my putzing aorund, fiddling with props, mixture, starving it, flooding it, pouring castor out of the pipe, bla bla.. it has probably amassed 5 minutes of running between gurgling rich and dying on surges by now. As soon as it cools down a bit - squeak squeak.. the fit hasn't perceptibly changed.

I know I have a small enough prop on it now.. It's all in the fuel supply.

The MDS .15 was a minor challenge by comparison.
Old 04-19-2015, 05:45 PM
  #54  
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Maybe try a one way check valve on your pressure line, to prevent the pressure from bleeding back out of the tank. It is amazing how much pressure is created when the system is closed off. It is like running case pressure. Just a thought.
Old 04-19-2015, 06:03 PM
  #55  
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My yet to be ran CS .061 Speed piped engine came with a pressure tap on the back plate.
Old 04-19-2015, 06:27 PM
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Crankcase pressure on the MDS worked really badly, when I changed to pipe pressure it ran like a charm. I may have had a pressure leak or some other dum dum.. that's why I am redoing the fuel system with more care and less "gotta run it now!".
Old 04-19-2015, 07:16 PM
  #57  
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Remember that the quality of the silicone pipe seal and the crankcase seal is a big part of the fuel system, too. It's one great big "Closed Loop".
Old 04-19-2015, 07:54 PM
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I have never liked case pressure either. So easy to flood. The starting procedure must be figured out and adhered to.
Old 04-23-2015, 12:22 PM
  #59  
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Originally Posted by combatpigg
Make sure to treat it / tune it as you would if it was a diesel.
As one who converts these engines to use stinky fuel, please let me in on this inside joke? Joke, yes?
Old 04-23-2015, 03:44 PM
  #60  
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Andy, Dave Shadel at Performance Specialties is the guy who drove this point home with me. Piped engines with high timing are every bit as sensitive to the compression adjustment as a diesel if not more so. You want to use the least amount of compression that will get the job done. In "glow talk"..prop load and nitro content need to be viewed as having the same effects as the chosen compression ratio.
It's possible to find the right combination that gives great performance and decent longevity, but it needs to be done carefully.
Since these engines don't come with compression screws, you've got to start out with a pile of head shims and start subtracting them until you can at least get the engine to bump, then barely run, then barely pre-stage, then possibly hit full song. During these trials, you must be using a ridiculously undersized prop as basically a cooling fan for the engine.
The next step is to begin increasing prop load until the engine shows signs of complaint. Hopefully at this stage you are near what your "Target Prop Size" is for speed. It's helpful to have an educated guess based on pre-existing research. There is not an infinite amount of incrementally sized props to find the best one, so at this point your new hobby has become "Prop Mod Man". The fine line between 195 and 200 mph can be just 5 minutes worth of scraping on any given sized "off the shelf" prop.
Old 04-23-2015, 09:34 PM
  #61  
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Originally Posted by combatpigg
Since these engines don't come with compression screws, you've got to start out with a pile of head shims and start subtracting them until you can at least get the engine to bump, then barely run, then barely pre-stage, then possibly hit full song. During these trials, you must be using a ridiculously undersized prop as basically a cooling fan for the engine.
This would be an example:

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Old 04-23-2015, 09:37 PM
  #62  
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I've replumbed it with a short line to the engine and different tank. The tiny prop is because I was having trouble getting enough fuel flow when it tried to stage, so I figured this would be a place to start with the new fuel system.
Old 04-23-2015, 09:53 PM
  #63  
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I suspect that prop has too much area near the tips. Why not try a cut down 4.2 x 4...?
Clip it to 3.75" or so.
Old 04-23-2015, 10:01 PM
  #64  
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The internal style pipe seal is what has caused me to chase fuel flow problems, but too much prop mimics fuel flow trouble too.
I would find myself with the needle backed out all the way and still too lean. A leaky crankcase will cause it too.
Old 04-24-2015, 03:41 AM
  #65  
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No leaks on the engine for sure. That prop is 3.25" diameter - and I still was starving for fuel on the last tank setup. I'm gone for a week down south, then when I get back it better bloody well have warmed up.. still getting sprinkles of snow this morning! Then I can continue.. I'll vid a couple of starts,
Old 04-24-2015, 09:26 AM
  #66  
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Just judging from the photo, my gut feeling is that it's scooping up too much air.
Is the spray bar "keyed" for proper orientation...?
I've never come up with a sure fire way to test the pipe seal, but it seems that for peace of mind an external seal could be added for peace of mind. If you melt out the seal during a hot run, there goes the engine. It's just like leaning out a cutting torch.
Old 04-24-2015, 11:23 AM
  #67  
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Originally Posted by combatpigg
Andy, Dave Shadel at Performance Specialties is the guy who drove this point home with me. Piped engines with high timing are every bit as sensitive to the compression adjustment as a diesel if not more so. You want to use the least amount of compression that will get the job done. In "glow talk"..prop load and nitro content need to be viewed as having the same effects as the chosen compression ratio.
It's possible to find the right combination that gives great performance and decent longevity, but it needs to be done carefully.
Since these engines don't come with compression screws, you've got to start out with a pile of head shims and start subtracting them until you can at least get the engine to bump, then barely run, then barely pre-stage, then possibly hit full song. During these trials, you must be using a ridiculously undersized prop as basically a cooling fan for the engine.
The next step is to begin increasing prop load until the engine shows signs of complaint. Hopefully at this stage you are near what your "Target Prop Size" is for speed. It's helpful to have an educated guess based on pre-existing research. There is not an infinite amount of incrementally sized props to find the best one, so at this point your new hobby has become "Prop Mod Man". The fine line between 195 and 200 mph can be just 5 minutes worth of scraping on any given sized "off the shelf" prop.
That is very interesting. Maybe explains why my CS just doesn't do what it's supposed to.

But there actually is a glow engine on which the compression can be adjusted on the fly. It's an invention of mine thanks to the head design of the Norvel. Patent pending once I get my issues resolved. https://www.youtube.com/watch?v=_pN6-rgXEFk https://www.youtube.com/watch?v=nRj_JEOXc54

It was cobbled together to make direct comparisons as to the benefits of diesel compared to glow. Same prop, same plane, like that. Good grief, that was 9 years ago.

The concept could be adapted to a .10 but there looks to be no room to do it with a 1/2A. Much like trying to install a turbo plug on to a TD .020.

Having said that, you never know until you try.

Last edited by AndyW; 04-24-2015 at 11:35 AM.
Old 04-24-2015, 11:33 AM
  #68  
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As I refresh my memory on this device, I'm reminded of my suggestion that the Norvel .15 was set up more like a diesel than glow. From one of the videos, the text suggests that this engine produced the same RPMs (on the same prop) glow OR diesel. But with the punch that diesel combustion provides, perhaps it won't bog down as easily as when run on glow fuel.
Old 04-24-2015, 01:09 PM
  #69  
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Andy, if your CS has 180 degrees of exhaust or more, then it won't be able to resonate like a 1/2 A Speed engine should with much more than a 4 x 4 prop [with really skinny blades]. This really limits it's usefulness to very small, thin and light planes.
Figure that it's designed to run at about 40,000 on FAI fuel.
If you can meet all the conditions required, then it ought to fly a RC plane at 150 mph +
Old 04-24-2015, 07:51 PM
  #70  
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Originally Posted by combatpigg
Andy, if your CS has 180 degrees of exhaust or more, then it won't be able to resonate like a 1/2 A Speed engine should with much more than a 4 x 4 prop [with really skinny blades]. This really limits it's usefulness to very small, thin and light planes.
Figure that it's designed to run at about 40,000 on FAI fuel.
If you can meet all the conditions required, then it ought to fly a RC plane at 150 mph +
Thanks CP,

And, well, that's my problem. I tend to run big lumber like 6 X 3 Tornados. And this is all kind of Deja Vu, we've been through this before. I may have notes on a to do list somewhere. Thanks for taking the trouble to repeat your good advice.

I took a pic of the exhaust end and hope you can make sense of what you see.

The glass/carbon prop is 5" X ? which I got from.. shoot, the nice man who sold VA MK2s a while back. But compared to the 4.5 X 2 Cox grey, it eyeballs as a 2" pitch. Would a 5 X 2 load the engine similarly to a 4 X 4? Or close enough? This IS the prop I used but I only had 5% fuel at the time.

You know, maybe I'm just not wired for screaming RPMs and 150 mph. I'd never find a place to find such a plane much as I'd like to try it. I could just sell it.

It's had maybe two runs, it's dead nuts clean, snaps over smartly, has new bearings, and includes the prop, a throttle and pipe. AND. the silicon O-ring. The only thing missing is the swarf that the factory generously provided as a bonus.
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Old 04-24-2015, 09:41 PM
  #71  
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Most of us can only fly a 24-30 inch span plane 300 feet or so before needing to turn back, so flying at 150 mph just means that you do it more often. If the plane is set up conservatively, it's a piece of cake.
The most difficult detail is conserving enough space under the pipe to fit a fuel tank. Ideally, the front silhouette of the fuselage is limited to just the engine's outline and the pipe is totally enclosed. High wingers hand launch the best, so an inverted engine seems to make sense then. 1/4" thick, solid balsa wing with inlaid full depth evergreen spars...you could throw something together for that engine pretty easily. The shrunken plastic bottle cowl method is quick and easy to do. I think you would enjoy trying it, just have a good pair of ear muffs [and foam ear plugs at the same time].
I used to use HS-55s and those really cheesy GWS RXs in my speedster and never crashed it [what a foolish idiot though].........
Old 04-25-2015, 06:02 AM
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You know, from day one I had a special attraction to 1/2A and small planes. When I was six, my Dad brought me into the local hobby shop and I still remember drooling over Cox's version of Betty Skelton's Pitts. The shop owner took it down and offered me a closer look. That little Cox engine was a real jewel and I fell in love with it all, ever since.

Those were the days long before digital radios and the like but eventually, RC came into it's own but with some pretty big and heavy equipment and we didn't have throttle so we made them super light, and 3 channel and had a lot of fun for our money. Still, I wondered, wouldn't it be neat to have a 4 channel, "pattern" ship as they were called. As time passed, Kraft offered a "micro" servo and Bill Canon came on the scene. NOW we're talking especially with Canon importing the G-Mark engine.

We haven't looked back since. What was micro back then are monster servos compared to today. A fully cased, proper servo at 1.5 GRAMS? I'd not have believed it possible. We can thank the advances in electric propulsion for that. BIG market, mass produced in the Orient, VERY cheap but still high quality. 1/2A heaven these days.

There was just one problem. In the old days, our small, fast and nimble planes were generally flown up there, where the big boys were flying. Today, we have "full house" planes that we can fly at practically eye level. This was great for us, but was a major distraction for those with the bigger aircraft at altitude. I was just flying and having fun, broke no rules and generally was unaware as to what was going on around me.

Because my flying was bothersome to some, I was resented and got negative feedback that I didn't recognize at the time. When it finally dawned on me, I went out to the local park. I was always afraid that I'd get kicked out but never once did any of the usual park patrons give me grief. One day, a local gendarme comes walking up and I thought that my flying days were over. But no, he was just a guy who always wanted to try RC. Imagine that. So I gave him details about the club and the field and the usual, cost, type of plane to start with, showed him the RX, servos,,,, how it all worked. He shook my hand and left and I was positively beaming.

Can't fly your suggested creation at the park but it's inspired me to keep the engine and make it do what it's supposed to do. You learn by trying and I always want to learn something new. What the hell, with hand launching, I can think of more than a few backwoods locations. We have what are called tailing ponds, sludge from the mines that hardens and lays out like a salt flats. Lots of room to go like a banshee.

I have the wood, I have the engine, I have the radio. Have Gun, Will Travel, was a popular Western TV show WAY back when. Well, have engine, will travel has a nice ring to it.

Thanks CP, you're a gentleman and a scholar.
Old 04-25-2015, 08:46 AM
  #73  
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That's the spirit Andy..! Make those high timed engines earn their keep...!
Old 04-25-2015, 11:50 AM
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Andy,
My TD.049s flew at 20+oz with Heathkit radio.
Flew them within two football areas of the field,
Got Noise Complaints.
From 'Pattern' flyers with piped .60 ST/Webra machines, spewing thier noise, far away from the Flightline,


This .049 project is really friggin scary. I have actually touched the engine, made my ass pucker !

I'm reseaching FAI rules, for a documented record attempt.

No Doubt, Mike knows what he is doing.

There is a fine line between 'awe' inspiring and stupid.

Just to have to make the time, and a perfect weather day, for all the Patience/Work involved...

I cannot, not be part of this project.

Pictures of Profi's are one thing,
Holding one in your hands,
And going, Whoh !
Is why,
Leyroy Cox,
Got me,
Started

Take care,
Have fun,
Dave'crosscheck'Fallowfield
Maac 6437
Unabashed Combat Team
Old 05-04-2015, 05:13 AM
  #75  
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Originally Posted by AndyW
T

The glass/carbon prop is 5" X ? which I got from.. shoot, the nice man who sold VA MK2s a while back. But compared to the 4.5 X 2 Cox grey, it eyeballs as a 2" pitch. Would a 5 X 2 load the engine similarly to a 4 X 4? Or close enough? This IS the prop I used but I only had 5% fuel at the time.

That was Larry Driskill. The glass/carbon props I have from him are 5 x 2.75, it's one of those I cut down for bench running the Profi.

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