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Old Mar 15, 2012, 07:08 PM
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United States, AK, Fairbanks
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Fuel for Norvel 074

I have a new norvel 074. I was planning on breaking it in on 0% nitro 25% castor fuel. For regular running, the manual says I need to run 20-22% oil with half of that being castor. I already have some cool power 15%, but its oil content is only 17% all synthetic. I was wondering if there would be any problem if I changed the fuel mixture to the following:

add 324ml cool power to an empty bottle (269ml fuel 55ml synthetic oil)
add 55ml castor
lastly add 121 ml plain methanol
Should end up with half liter of 22% oil 50/50 castor synthetic + 8% nitro.


I was worried that the cool power oil percentage might not be measured by volume. Does anyone see any problem with this plan? Will the engine be okay running this?
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Old Mar 15, 2012, 08:35 PM
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Yes you can add oil to increase the percentage. Granted it does change the ratios some, but not really all that much to affect it too much. Adding more methanol is a good idea. So there is no problems with your idea that I can think of.
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Old Mar 16, 2012, 01:25 AM
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I prefer to use full castor oil fuel (20-25%) on the Norvels, they are very tight when new and take a long time to break in. Use a heating gun or small torch to relive the TDC pinch.
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Old Mar 16, 2012, 04:44 PM
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Quote:
Originally Posted by wilevi93 View Post
I have a new norvel 074. I was planning on breaking it in on 0% nitro 25% castor fuel. For regular running, the manual says I need to run 20-22% oil with half of that being castor. I already have some cool power 15%, but its oil content is only 17% all synthetic. I was wondering if there would be any problem if I changed the fuel mixture to the following:

add 324ml cool power to an empty bottle (269ml fuel 55ml synthetic oil)
add 55ml castor
lastly add 121 ml plain methanol
Should end up with half liter of 22% oil 50/50 castor synthetic + 8% nitro.


I was worried that the cool power oil percentage might not be measured by volume. Does anyone see any problem with this plan? Will the engine be okay running this?

Why would you want to "break-in" this engine with no nitro? Seems that would be detrimental to long piston/liner life. ??? ............. George K.
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Old Mar 16, 2012, 04:48 PM
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He may not be from the USA and glow fuel with nitromethane in it can be much more expensive in some countries.
The engines do run OK with O% nitro in the glow fuel. You just don't get that extra power out of them you do with nitromethane. Also the needle valve tends to be a little more sensitive in its setting. You could also remove a head gasket shim or two to increase the compression a little more for 0% nitro fuel. If I remember correctly the engines come with three stacked head gaskets in them.
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Old Mar 19, 2012, 11:13 PM
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When Peter Chin broke an engine in prior to review, his standard mix for most engines was 75/25 methanol/castor.
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Old Mar 20, 2012, 10:37 AM
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Quote:
Originally Posted by NACA0012 View Post
When Peter Chin broke an engine in prior to review, his standard mix for most engines was 75/25 methanol/castor.
I 'd be quite surprised to learn that Mr. Chin would have "broke-in" a Norvel .074 with "no-nitro" fuel. Because of the unique metallurgy, & the greater than normal iterference fit of the P/L at TDC, it's quite important to get these engines up to normal high temperature soon as possible during the first several runs. ....
Maybe, like earlwb said, W93 may not be from the states. He may well intend to use "no-nitro" fuel even after the engine was broken in. If so, the fit would be fine, but some power would be lost. However, if that same engine were then to be used with the (what I call) norm 35% nitro fuel, the p/l fit would be loose. .......
George K.
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Old Mar 20, 2012, 11:20 AM
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Most important for running-in the engine is to use a heating gun to pre-heat the cylinder and reduce the pinch at TDC.

You will not brake any engine by running with 0% Nitro, on the contrary lower nitro requires less compression ratio. The price of 10% Nitro fuel is about twice as high as for 0% Nitro here, so that is one reason to use low nitro levels. Some engines tend to run a little warmer on 0% nitro though compared to 10% nitro.

Here is my Norvel .074 running on 10% Nitro and 20% all castor fuel;

Super Chipmunk (speed 400 ARF) on glow (2 min 56 sec)
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Old Mar 22, 2012, 02:16 PM
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I have used and flown a number of 1/2a engines with no nitromethane in the fuel. You might lose some power and it makes the needle valve more sensitive to adjust, but the engines run just fine. With some engines you can remove a head gasket shim or two and it improves the performance quite a bit. The engine temperatures are about the same for with or without nitromethane in the fuel. So it isn't a big deal.

I never tried it with a Cox .020 engine though, so that I don't know, if it will work or not.

Post number 22 in this thread here http://www.rcgroups.com/forums/showt...1346066&page=2
show another fellow going with FAI fuel in a .049 engine.
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Old Mar 22, 2012, 03:02 PM
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Sure you can get the .020 peewee to run on 0% nitro, but the problem is that the needle becomes very sensitive. The tank will heat up during a run and you have to chase the needle. You'll never manage to empty the tank, been there done that....

The Peewee runs much better as a diesel, long consistent runs all the way till the tank is empty and spins a 6x3 prop at around 10000rpm.
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Old Apr 02, 2012, 01:12 PM
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As far as I can tell, this is a controversial subject. Some people say you should use nitro, others say you don't need to.

Somebody needs to do a test with a temperature gauge to see what runs hotter, 0% nitro fuel, 10% nitro, castor, synthetic etc. It's my opinion that 0% heats the engine more since the ideal fuel/air mixture is leaner than with nitro fuel.

If 0% does run the hottest, it means the upper cylinder should expand nicely, preventing wear, also adding to prolonged engine life would be that you don't have the high pressures and stress in the engine as with nitro fuel.

If power is your main concern, then you should use nitro fuel regardless of engine wear.

Nitro fuel is a little expensive to buy where I live. (Alaska)
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Old Apr 02, 2012, 06:41 PM
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[QUOTE=wilevi93;21215406]As far as I can tell, this is a controversial subject. Somebody needs to do a test with a temperature gauge to see what runs hotter,



OK guys, first off, I'm fully aware that model engines can be run on "no nitro" fuel without destroying themselfs. The key words here, (in the opening post) are "breaking it in on 0% nitro". My concern was that the revlite norvels should be run up to get near max temperature asap when breaking-in. If that temperature was on the cold side for the first couple of runs, & then a switch to a "hi nitro" fuel was made for every day runing, the engine would be somewhat loose for the nitro. .................. So, after wilevi's last post, I removed my oldest Norvel .074 engine from its airframe & mounted it on the test stand. This engine has gone through 'bout 3 gal of fuel (33% nitro, & 25% oil). Just about all the run time has been at full throttle. ( bench readings 19K to 21+K; I don't have any doppler data so no telling what the unloaded RPMs are) with either Mas 5.5x4 or 6x4 props. It is quite loose, & has virtually no "pinch" left at TDC. Compresston, however is still quite good. .................. Three test for RPMs & temperature were run. ............#1; 2 shims & 33% nitro............... #2; NO shims (just a dab of Hylomar smeared on the bottom of the glo head) & no nitro. ....
#3; 2 shims & no nitro. ( The "no nitro" fuel was SIG's so called FAI fuel) All runs were made with the 5.5x4 prop. Test #1 gave 21,300 RPMs & 238deg F.........
Test 2 gave 21,000 RPMs &190 deg F. Test 3 gave 20,000 RPMs & 183 deg F.
Got to admit, (and eat a bit of crow) that I really expected much more than a 50 deg temperature difference between Nitro, & no Nitro . ................ Test #2 was a bit of pleasant surprise. Starting was a bit more cranky. ( had to give up flipping & grab the electric starter), & the needle was a bit more touchy, but the engine really transitioned & peaked nice. Idle needed to be a few hundred RPMs higher. (Maybe a carb with low end adjustment would help.???) ALL told, not much of a price to pay for almost identical top-end performance.!!! .......... Test 3 was a real pain. About 6 starts, before the engine would stay running. Then, I had to move the throttle very slow for just a few % & wait for the temperature to come up & let the engine start to run clean. Made it up to full throttle, & setting the needle was a real bear. Even after the temp. came up, & the needle was as good as it was gonna be, the engine would not continuously run "clean" . About every 5 seconds, it would give a single "burp". Don't have a clue as to what is causing this. (not enough combustion chamber temperature???). Regardless, what the cause, test #3 certainly ain't the way to go. .......................... Got to list a couple of possible pitfalls with this test. First, Damn cold in my basement with the double garage doors open; 'bout 38 deg F. .... Second, I'm not likeing the IR scanner, & the big differences of readings as I moved the scanner just a bit from an area in back of the clamp to just a tad more into the air stream. Think that a thermocouple or platinum RTD fixed to the back of the clamp would be much better. Also, might be better to kill the engine & immediately take the readings.?? Hopefully, I haven't bored everybody to sleep, & that there was some usefull info to be gleened from this long winded post....... (Comments, + or -, not only welcome, but requested......... George K.
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Old Apr 02, 2012, 07:34 PM
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Well, what I can glean from looking at the data is that running 0% nitro, although it is running leaner, it still won't develop as much heat as fuel containing nitro. It also develops less power which is to be expected.

38F ? Ha, that's nothin. I started my TT-07 at 10F in my driveway, just to test out if using a candle to preheat the engine is a viable method...... It's not, I had to use a hair-dryer to properly heat it (sigh) no winter flying for me.
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Old Apr 02, 2012, 11:54 PM
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United Kingdom, England, London
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I am sure engines run cooler with more nitro!
Well to a certain extent, when I ran FAI fuel in my engines they ran hotter and less steady harder to needle and sometimes sorta "skipped".
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Old Apr 04, 2012, 03:18 AM
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1) Less nitro means the engine needs MORE compression.

2) Break in the engine with the % nitro you plan on running. If you run 0% nitro, break in with 0% nitro. If you run 15% nitro, break in with 15% nitro fuel.
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