glow engines...whats the difference?
 

Ive had a few nitro trucks and there a pain to keep tuned and running and don't last very long, I was wondering how do nitro airplane engines compare? Easier harder? What's the differences? Thanks

RE: glow engines...whats the difference?
 

I have had them both... I would say airplane engines are a little easier. just my 2 cents worth.

RE: glow engines...whats the difference?
 

Do you use an air filter?

I've noticed that car fuels tend to be lighter on oil content than a lot of airplane fuels. You might try using airplane fuel of modest nitro content (5-10%) with some castor oil in it. I've had airplane engines run for many hundreds of hours with low nitro fuels that had castor oil in them. The one's that have been whipped hard with 40% nitro in competition tended to wear out and break faster than the more conservatively run ones.

Any engine take a while to break in properly too. Even the supposedly "quick" breaking in ABC's can take 45 minutes or more of gentle treatment before they're really ready to flog hard. Rush the process and longevity and performance ultimately suffer.

RE: glow engines...whats the difference?
 

I always run a air filter in all my aircraft. I use them on my 2 and 4 strokes. On my 2 strokes I run 10% and my 4 strokes I run on 15%. I bought a whole bunch of Bru Line Air Filters and Boots just when they became discontinued. I bought enough to last me for years and cleaned out my LHS when they had them. A engine is a engine no matter if it's a 4 stroke or 2. The only differences is the fuel and the 4 stroke has more moving parts. (Talking about theory, not design)

I don't know why some people don't use filters when most of us have found dead bugs, dirt, dust, sand and grass clippings on or around our aircraft. To me it's just plain obvious that it would be smart to slap on a air filter. Plus, I notice my engines last longer and run a little better with a air filter on it. And to top it all off, I always put on a fuel filter. Never know what junk from the bottom of the jug slips through the glow tank.

That's my take on it.


Pete

RE: glow engines...whats the difference?
 

Thanks for the quick replies but it doesn't really answer my question, I guess I should be more specific, with a land Rc you have to constantly be tuning it about every time you run and while you run, are planes the same or does it hold a tune or what? If that came across rude I didn't meen it that way I appreciate the input. Thanks

RE: glow engines...whats the difference?
 

Many times for me, I tune quickly before the first flight of the day, as it warms up I may need to retune if I got to the field early in the morning. Generally for me, it was a tune first thing, maybe the second time and after that, I dont touch a thing. My glow planes have been knockaround planes and so I am not terribly fond of tuning and tuning and tuning. I know one guy that spent 45 mins tinkering with his glow plane and then after messing with everything and not getting it the way he wanted, he packed up and went home to change out all his fuel lines. All while he did this, I was flying and saying to my buddy standing next to me, "sounds great, when is he coming up with me?".. I remember tuning the crap out of my Revo all the time and I hated it. I found airplane engines to be a treat by comparison..

RE: glow engines...whats the difference?
 

G'day

I have only run aircraft engines. Lots of them. My engines seem to last quite a long time. Several years is typical and the only engine I think I actually wore out was my first one - an OS 15 II way back about 1960. I ran it too lean most of the time and it wore very fast as a result.

As for tuning, most of my engines need very little tuning apart from when the temperature changes a lot in Autumn and Spring and when I change fuel mixture or prop. Mostly I fly the engines week after week at the same tune.

The tricks to getting engines to last is -

1. Don't tune too lean. Too rich is slightly less powerful but will last a lot longer.

2. Don't feed the engine a "high silica diet". ie Keep dirt out of the engine. Use a filter and clean it.

3. Keep the engine clean too.

4. Use as little nitro as you can. Nitro can cause rust from its combustion products. It does make tuning easier but it will shorten the engine's life the more you use. Up to 15% is usually OK.

5. Use enough oil in the mixture. I always use at least 20% of which one quarter is castor oil. Castor is a great insurance against lean runs and rust but it does cause varnishing and is gunky.

I had one Saito 45 four stroke that I and others ran for over 15 years. It needed some new bearings when it was about 15 years old but I believe it is still going and is now about 20 years old. They can last a long time.

Cheers

Mike in Oz

RE: glow engines...whats the difference?
 

That all depends- not all people with glow or gas know how to tune their engines correctly. On aircraft glow engines we have to properly break-in the engine. Different makes takes a little longer than others to break-in, and if not done properly could not only damage the engine, but would also make the engine unreliable. ALL GLOW ENGINES MUST BE BROKEN-IN. DON'T BELIEVE WHAT THEY SAY AT THE MANUFACTURE!

For me once I adust my midrange, and get it just right where it doesn't stall out at the same time gives me a smooth rhythm, then I adjust my top end. Not once have I had to re-adjust my low or mid-range. Once that is set, I leave it alone.

Every time before I fly (first flight of the day) I have to adjust my top end needle a few clicks either to enrich or lean because every time the nose of the aircraft pitches up, it wants to lean out a little. However I only have to do it once for the whole day if done right. When the nose of the plane is pointed down it wants to run more rich. What I look for is that happy medium. No matter how I move the plane up or down, I can't hear much of a rpm difference. Some use a rpm gauge, I don't because I have a pretty good ear.

The reason why we have to adjust the high end is because every few days the barometric pressure changes including tempature. Each time it changes, we have to adjust the high end a little to compensate.

The big difference I know between a airplane glow engine and a car glow engine is the crankshaft and head design is different. The car engines are shorter in crankshaft length. Also the cooling fins on the head and cylinder are larger for the car because a car doesn't create the same type of speed like a aircraft does and needs the extra fins for cooling. Look at a helicopter engine and they are simular in design to the car engine ie helicopters don't usually fly at high rates of speed like a fixed wing aircraft does. Most like to hover with their helicopters except for the 3D helicopter pilots.

Every engine is designed for specific purposes. Most cars have a rope start, we have a hand held electric starter and place it on the nose cone or the end of the crankshaft. A rope start on a plane engine is not safe and kind of impractical.

A car engine can stall, but you'll always get your car back in one peice. A aircraft engine or helicopter glow engine stalls, we might not get it back in one peice, therefore I believe the engine that are designed for flight have a tighter tolerance and were designed more for dependability. That's a wild guess on my part but to me it would make sense.


Pete

RE: glow engines...whats the difference?
 

That's what I was looking for, thanks for all the help guys. And 20 years on a glow engine!!!! WOW on a truck engine you normally get about 5 gallons before its toast. After hearing all that I may try nitro again but with a plane.

RE: glow engines...whats the difference?
 

I have a 1983 O.S. 120FS (Before Surpass) The one that looks like a Saito? I've only had to replace the glow plug, tappets or valve adjusters because the allen head started to get worn. And last but not least, I made some shims out of brass washers. Originally they had teflon washers as shims on the rocker arms, but they wore out. So I got with a guy who restores classic glow engines and he showed me how to machine impossible to find parts by hand.

I just put on a 91FS Surpass muffler on it now and it even runs better. Last year I had to replace the carb but other than that the engine runs like it is new, and she looks good. Compression is excellent, I slapped it in a .90 Extra 260 last year and she had a lot of power. Even after my crash, she looks new and has no damage. I plan on putting it in another WWI bird. Rubber O-rings are still holding up after all those years and still I have no leaks.

Pete

RE: glow engines...whats the difference?
 

If you're only getting 5gal out of an engine, then there's something wrong. It's too lean and burning up the P/L and other wearing surfaces, or maybe the fuel doesn't really have enough oil, or it was half wrecked during breaking it in.

What is a typical failure mode when they die? Loss of compression? bearing failures? mechanical breakage? Seizing?

RE: glow engines...whats the difference?
 

Exactly! Rather have it a little rich than lean. I wanna see some smoke man! :DLOL!


Pete

RE: glow engines...whats the difference?
 

I came to RC aviation from the ground side too......I thought something must be wrong as glow plugs lasted forever......you'll find that RC aviation engines last alot longer....less vibration and more cooling air....70 to 100 MPH is the norm for us...verus 35 to 50 for the ground side
Once tuned you'll hardly mess with the tuning again

RE: glow engines...whats the difference?
 

I believe that car/truck engines, like boat and heli engines are higher revving and higer performance engines than standard airplane engines.  That means they will wear out faster and need more "adjustments".  Just looking at OS fore example the .21TM car engine goes to 35K and has 1.7 HP wil the .25FX airplane engine goes to 19K and only has ,84 HP.</p>

RE: glow engines...whats the difference?
 

My 2 and 4 stroke airplane engines are reliable and rarely require adjustment.

RE: glow engines...whats the difference?
 

I have to retune my Aircraft engine once in a while depends on season. As with the Truggys yep all the time to keep them at peak. But car engines are usualy at a higher work load and RPM and peak out all the times.
I find a lot of car engines fail because of too lean at peaking, running without the air filter, not run in properly because they lost patiance trying to keep it going when it was easy to run them at peak...

RE: glow engines...whats the difference?
 

Car engines take a beating. All that shock loading, jumping, crashing, dirt and grime can't be good for them.

RE: glow engines...whats the difference?
 

I don't run cars but have helped those that do a few times. Dirt and lean runs seem to be the killers on these little screamers. Just because it has an air cleaner (most are fairly crude) doesn't mean some dirt isn't getting thru. Like anything else the air cleaner
must be serviced often or it will restrict and change needle settings as it clogs up. Most cars seem to be owned by those who demand the highest rpms at all times, thus starting out on the lean side.
That combination will kill any engine large or small.
I have owned large Bull Dozers that required air cleaner service every day and the dirt collected was in the pounds, some of the small model off-road vehicles are operating in about the same conditions with a little foamy "air cleaner" that I wouldn't consider using on
anything I valued.[:@]

RE: glow engines...whats the difference?
 

accually thats fairly normal, Ive seen people get lucky and get 10 but ive also seen people only get a couple but that's normally User error.

RE: glow engines...whats the difference?
 

RPM and cooling are the big differences. We don't try to ring out every RPM we can get from an engine and a planes cooling system is way better. RPM can be controlled with prop selection. When tuned we run up a plane engine to the max RPM we can get then back off 4 or 5 hundred RPM rich. Between that and the cooling, our plane engines last for years without ever requiring a rebuild. Only time I touch my needle is during big weather changes or when I change prop sizes. The fuel and oil type and content can effect the life of a plane engine but that's another topic.

RE: glow engines...whats the difference?
 

Your car engines are designed to run with high rpms, a wide range from idle to full throttle. The carb has to be tuned to run in this wide range, which makes it touchy. Also you mostly have tuned pipes, your settings have to be perfect to get them to run right.
In an airplane the nitros are much easier to handle, when you do you first run up on the field, you check the mixture needle usually once and fly all day. When you break your engine in, it needs more tuning.
Some engines need more attention then others, but there are a lot more reliable then the car engines.
Once in a while I run the Tmaxx which I preferred because it has an onboard starter and you can put the battery for it in your pocket.

RE: glow engines...whats the difference?
 

Do you have a midrange needle valve on your engines?

Kurt

RE: glow engines...whats the difference?
 

Are you asking me? If so no just high speed and low speed if I remember right.

RE: glow engines...whats the difference?
 

In the past Fox has produced some 3-needle carbs with midrange adjustment. When setup according to Fox's instructions (which most people ignored), they were quite good.

Most are two needle, or simple one-needle with air bleed these days though.

RE: glow engines...whats the difference?
 

Most glow engines I know of only have a low end needle valve and a high end needle valve. I adjust my mid-range through the low end needle valve. Some people in this hobby don't know how to do it correctly nor have they ever heard of getting the mid-range adjusted IMHO.

To get a perfect low end/mid range, get your glow engine started and run it at full throttle ( Thats to clear the motor ) then go half throttle. VERY CAREFULLY, adjust the low end until you hear the engine smooth out. (I use a wire clothes hanger and beat a flat tip on the end if you don't have a very long thin screw driver. That way my fingers stay away from the prop and can keep my hands at a safe distance)

Keep turning low end needle clockwize until you here it slightly decrease in power ( That means you are too lean ) so turn it back counter clockwize until you get that fast nice smooth RPM, then turn it 1/16 to 3/16 turn more, then leave it. Now throttle down for a bit and move the throttle at a good pace to full throttle.

Now it's time to adjust the top end. Once you have the top end set the way you want it. Tilt the nose of the plane up, if you hear the engine rpm slightly increase, that's good. Me I try to find that happy medium that I had already mentioned.

Now the real test after doing what I suggested.

Let the plane idle for about a 2 minutes, now slam the throttle forward. You should get a very slight hessitation, then your engine should go full power without coughing or quiting.

Ever since the President of my ex-club showed me how to get the settings right on glow engines, I haven't had to re-adjust my low end or mid-range. Make sure your plane is properly secured when adjusting your carb. It's best to make all the adjustments on a engine stand if you have one, but if you don't you can still adjust the engine while it's in the aircraft. Just be careful.

This procedure works for all 2 and 4-stroke glow engines. ;)

Pete