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OMG it arrived - Profi speed .049

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OMG it arrived - Profi speed .049

Old 04-17-2015, 10:10 AM
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combatpigg
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I think it's the tight ones that you want to buy [if you are lucky] and just figure that you will need to spend time to get it just right. It's tough to determine what is "just right" if you aren't very experienced, if if you don't have a "GO - NO GO" method to know when to stop honing.
I have had success with using a steel handle fitted to the piston [using the piston as the honing tool] and fine sink scrub powder mixed with oil as the abrasive.
Fox used to sell a powder called Lustrox to dump into the old iron engines to polish them while they were more or less broken in. It might have done some magic microscopically to fill the pores. I don't know what the ABC or AAC equivalent of that process is.
Old 04-17-2015, 10:49 AM
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I have 3 CS engines the Sport RC and CL .061's seem to be reasonable for a new engine with flipping over with some after run oil.
Ran up the RC sport version with a 1/2A starter no problems. The ABC speed engine is very snappy when turned over with a bit of after run oil.

The material used to polish / clean car light lenses or plan cream tooth paste should work too.
Old 04-17-2015, 12:11 PM
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Originally Posted by aspeed
We used to break them in with no pipe so it would not get too hot. I think that nowadays the plan is to break them in at the operating temps, but well on the rich side. That CS was nasty tight. Not even heat would do much there. It is good now, just a manufacturing "defect" The CS is more of a kit motor that you have to fit yourself. I am sure the Profi is much closer to being right. The pipes on the F2A stuff sometimes have adjustable outlet sizes that screw in. I think 4.__ mm is about average for them. Quite small really, as the F2D is more like 6mm, which is down from the older 8mm.
Both the .049 and .061 had real nice fits, a wee pinch up top, and lit up fine on the first runs. I'll assume the same on the speed - for the price I am not expecting an engine kit, nor do I believe it is one. Beautifully made.

Yup, 4mm on my Profi F2A - I was advised that for extended runs or 10% fuel, to open it up a little to scavenge more heat. It does not have stinger inserts. The small outlet diameter on a resonant exhaust doesn't surprise me, nor does a more open outlet on a non-piped engine where scavenging is the goal.

I would have bench run the F2A by now but I can't put it in a regular mount, I'll make an Al plate for it sometime soon. The airframe arrives today or Monday, then I gotta get my butt in gear on the rework.

Open pipe to avoid heat buildup makes all the sense in the world - the F3 speed guys do this all the time. But I was also told that - regards the current good speed engines - in most cases you just go out and fly 'em.
Old 04-17-2015, 12:17 PM
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Originally Posted by Pond Skipper
The material used to polish / clean car light lenses or plan cream tooth paste should work too.
I've also used Mother's polish and 2000 grit polishing compound, the former recently did a good job on an iffy Norvel crank fit. Well, I think it did a good job, the crank freed right up and the engine works.

For a McCoy Red Head, sand or fine gravel should be about perfect.
Old 04-17-2015, 05:25 PM
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The high silicone pistons have a lot of hiding places for grit. Take a look with just an eye glass at how rough these parts really are up close.
Old 04-17-2015, 05:46 PM
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At 50 X it looks like the moon eh wut

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Old 04-17-2015, 06:47 PM
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Some pistons look even worse, but I think what you show is "State of the Art".
My local "mentors" taught me to make a sonic cleaner with either a denture cleaner or an orbital sander and place new or reworked engine parts in solvent, then give everything a good shaking until you feel that it's good enough. One guy would leave the parts buzzing away over night in a denture cleaner. He was one of the Top Dogs around here when it came to this stuff, so nobody questioned his swarfaphobia.
Old 04-18-2015, 10:13 AM
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All the errands done, I think it is time to set up the Profi outside and make some noise!
Old 04-18-2015, 12:19 PM
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First starts - clipped combat prop 4.5x2.75 - too much shaft load I think, can't get it past overrich low speed or starving for fuel.

Just returned from the basement - now it's 3.8x2.75 (and carefully balanced).

I am not really sure how to mentally equate 1 blade to 2 blade shaft loads. These would normally run a SB 2.875 x 4.0-4.5 or so, that means it scribes a 5.25 diameter circle.
Old 04-18-2015, 12:48 PM
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Have you made your spinner prop ready what is the bolt size in MM and the spinner dia?
Old 04-18-2015, 01:44 PM
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I am not really sure how to mentally equate 1 blade to 2 blade shaft loads. These normally run a SB 2.875 x 4.0-4.5 or so, that means it scribes a 5.25 diameter circle.

First starts - clipped combat prop 4.5x2.75 - too much shaft load I think, can't get it past overrich low speed or starving for fuel. [UPDATE] no I think way too much fuel pressure is the problem. Pipe tap time. Will have to rob a small pressure fitting from a Norvel for now.
Old 04-18-2015, 01:45 PM
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Originally Posted by Pond Skipper
Have you made your spinner prop ready what is the bolt size in MM and the spinner dia?
I'll get it measured up tonight I hope, haven't mapped the pipe yet either. Too much fondling, then whipped up the test stand today and ran outside.
Old 04-18-2015, 02:02 PM
  #38  
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Dont worry about the pipe I bought two of them off Alberto - today a sent him an email for cost on spare spinners I need a small one for my Norvel.
Old 04-18-2015, 02:28 PM
  #39  
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Which piston would you want to use

AP .049 RC

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Old 04-18-2015, 03:29 PM
  #40  
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I am pretty sure Fox supplied Lustrox with one or two of my combat engines. Some of my old CL buddies said that Jewelers rouge works for a lapping compound.

One of these days I need to break down and get a couple of Fora CL combat .049's. Kinda sad, I will be at the AMA Nats this summer, at the same time as combat, but will be flying another event. Last year an old buddy let me fly one of his FAI Fora .15 powered combat models. What a treat that was. Right before I left to head home as well. That made me smile for the trip home.
Old 04-18-2015, 04:41 PM
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Originally Posted by vertical grimmace
Last year an old buddy let me fly one of his FAI Fora .15 powered combat models. What a treat that was. Right before I left to head home as well. That made me smile for the trip home.
This is something that more RC Speed flyers should try..!
Old 04-18-2015, 04:53 PM
  #42  
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Originally Posted by MJD
First starts - clipped combat prop 4.5x2.75 - too much shaft load I think, can't get it past overrich low speed or starving for fuel.

Just returned from the basement - now it's 3.8x2.75 (and carefully balanced).

I am not really sure how to mentally equate 1 blade to 2 blade shaft loads. These would normally run a SB 2.875 x 4.0-4.5 or so, that means it scribes a 5.25 diameter circle.
MJD..I've lost track of what you're doing. Are you running it with a pipe..?
I found that a 4.2 x 4 was marginally too much for a piped .061. It was better for the engine with the airfoils thinned out. If you take 4.2 x 4.2 x 4 =70.56...that gives you a load factor that I'd say is too much for a new engine that you are playing with. Consider the 4.2 x 4 "swinging for the fence".
I could have been using too much compression and nitro...I don't remember those details. I wasn't using any more than 10 or 15% nitro, but I wasn't being very careful about my approach.
Old 04-18-2015, 05:28 PM
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Yes, piped. I'm changing over to pipe pressure tonight. Pressure was a nightmare on the MDS, pipe pressure fixed everything. Could just be my learning curve.

The engine never got hot or complained, it amassed 2 minutes or so of gurgling, frantic pinching, and eventually some steady running in the teens. Squeaky fit still. The workmanship is really good on these Profis.
Old 04-18-2015, 05:29 PM
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Too much in the air or on the ground?

If you put the pressure tap at the apex of the pipe it is the most constant correct?

Last edited by Pond Skipper; 04-18-2015 at 05:33 PM.
Old 04-18-2015, 05:32 PM
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Pond Skipper, I would rub the top of the AP piston on some 600 sandpaper first to get rid of the nasty machining marks. Isn't it an .06 or .09? I didn't know that they made an .049. I lap my motors with Brasso or Silvo. Can't wait for the numbers on the Profi. I think I will run up my piped CS and Fora .049 soon, as soon as I get some time. Got some building construction and a move coming up.

Last edited by aspeed; 04-18-2015 at 05:35 PM.
Old 04-18-2015, 06:02 PM
  #46  
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Yes my bad its a .060 I have a grinding stone new very flat, I thought about doing that on the CS engine as well.
Old 04-18-2015, 06:31 PM
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I don't think it would matter much, maybe the carbon may stick a bit easier. I have an AP .15 with chatter marks and grooves on the piston, but it seals well, and fits well and runs great. The grooves may hold the oil better, or cool things better, who knows.
Old 04-18-2015, 06:49 PM
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Yes thought about distribution but then the grooves are great way to collect hard deposits.
It's possible the cylinders could have been milled to level them off without the added cost to remove the tool marks.

Last edited by Pond Skipper; 04-18-2015 at 06:52 PM.
Old 04-18-2015, 07:30 PM
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According to Nelson, pipe pressure is the best was to get proportional fuel delivery.
He does not approve of bladders, since the bladder has no way of "ramping up" for a huge unloading.
This engine ought to turn a 3.8 x 2.75 with ease, even with open exhaust.
If the engines runs balky and dies unexpectedly, look at the glow plug to see if it's wet or not.

Last edited by combatpigg; 04-18-2015 at 07:33 PM.
Old 04-19-2015, 03:52 AM
  #50  
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It became very obvious that pressure doesn't work worth beans, for exactly that reason - does not respond to the widely varying fuel demand. I already dropped a 2.5mm pressure tap on the pipe - later today will try out,

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