Mini Temperature Guns! The "Hottest" Thing
 

I see these little laser temperature guns popping up everywhere and most seem to work just fine. Thing is where are the specifications on cylinder head temps? Now I have flown some engines which overheated and I know how they respond and the performance which follows but where are the numbers for every make , model and size.
The reason i brought this up is a guy had one out at the field. He was checking the temp and when i asked him what the range was, well lets say their were others around and made him feel stupid and avoided me the rest of the day.:eek:

RE: Mini Temperature Guns! The "Hottest" Thing
 

Is there really a use for these things? I know they,re used in refrigeration and air conditioning. If I was still doing that, I'd get one. I can't see that they'd be useful except to balance multi-cylinder engines; for singles, I think the old ways should work just fine.

RE: Mini Temperature Guns! The "Hottest" Thing
 

I have one and use it for measuring head temps on rc car engines. Manufacturers of car engines give temp ranges and cooling is an issue with them. I also use mine for HVAC as mentioned, so I could write it off as a work expense. LOL

Warren

RE: Mini Temperature Guns! The "Hottest" Thing
 

A typical 2 stroke (and quite possibly 4 stroke) engine should run in the 300 to 350 degree F range.
Dennis-

RE: Mini Temperature Guns! The "Hottest" Thing
 

I have one and use it quite often during the season. Mainly, I use it to check the cylinder head temps to see if I need any cooling baffles when flying a new airplane. After that, I use it once in a while just to see that everything is still good. On the gas twin cylinders, a range of around 200F-225F is acceptable. I also use it on turbines to check heat ranges around various points on the fuselage, exhaust, etc.

RE: Mini Temperature Guns! The "Hottest" Thing
 

Where Mr. Faust has a good point for checking hot spots around his jet, for most of us using our single glow motors and small twin gassers in airplanes, the ear, a tach (to detect reduced performance mainly, the ear is better for daily tuning), and a little bit of experience is the best answer.

To reduce my thoughts on some simple points, ground temps and flying temps are totally different (not combustion temps but on the cooling fins themselves), and flying temps change radically dependant on throttle settings and nose attitude. Over running tightly cowled motors on the ground will often cause overheating that never occures in the air. The propellor does not push as much air across the baffles as does the low pressure, fast moving air across the exit will pull through the cowl intakes.

On another viewpoint, many modellers are gadget fanatics so why spoil their fun? If they want to take their motor's temperature then I say "have fun".

Gadget freaks are to blame for most of the nifty inventions we play with anyway!!!

Mark

RE: Mini Temperature Guns! The "Hottest" Thing
 

they are neat but I have gotten by just fine for years in nitro cars and planes without them. one guy at the field uses one all the time and really has no idea how to run or tune an engine anyway but he really thinks the thing is useful. i think he just loves to play with it and watch it read numbers out. many guys put the cart before the horse when it comes to gadgets i think. they dont know the basics well and get advanced toys but cant get the value or usefulness out of the new toy because they dont know what they are doing to begin with. i think a digi tach is far more useful

RE: Mini Temperature Guns! The "Hottest" Thing
 

I like them but there needs to be a little laser to show where you are aiming. I was checking my engine and kept getting really high readings. I found out that I kept pointing it at the muffler. The laser would show where you are getting your reading.

RE: Mini Temperature Guns! The "Hottest" Thing
 

The one I was referring to has a laser on it, its a RayTec (or similar name). Evidently, this thread may be about a different one.

RE: Mini Temperature Guns! The "Hottest" Thing
 

I got a radio shack one (looks like the DuraTrax one in the tower flyer) and it works great on RC cars. My T-Maxx they recommend a temp of 230-250 and anything over 300 yer in trouble. I's great for tuning the engine and richening when it's too hot.
When I'm bashin my maxx it's the one tool I can't be without.

I don't think airplanes are as sensitive to heat as the prop usually supplies enough air over the head to keep it cool.

RE: Mini Temperature Guns! The "Hottest" Thing
 

The bad thing about the laser aiming point is that on some of the cheaper guns, $100 and less, it is offset from the point the reading is taken at the distances we normally use the gun at. If you move back to where the aim pint and the point the reading is taken match the area being read is so large the data does not mean anything.

They are great on buggies and trucks that you can pull right up to your feet quickly after a hard run and get a reading. Have not figured out how to do that with a plane except to crash it.

Where I have started using it is when breaking in an engine on the bench to make sure it is not getting too hot.

Ed M.

RE: Mini Temperature Guns! The "Hottest" Thing
 

No need to wreck an airplane just to check the temps ;) Run it hard on the ground while being held by a helper, and measure it while running if the engine is open. On the larger gas engines measure it immedately after shutting it down and check both cylinder heads. Consistancy is the key if you are going to measure differences for tuning, baffling, cooling, etc. Ie, if you lower it 20 degrees on the ground, than you most likely lowered it 20 degrees in the air as well, even if the ground temp is different from the 'in the air' temp.

If the air is not directed over the cylinder heads properly, it will not cool the engine. The air will take the path of least resistance, which unfortunately is not usually through the fins. Many gasoline airplanes are fine without any baffling, but many do require baffles to direct the air through the fins and not around it. The temp guns allow you to determine if baffling is required, as well as measure how effective the baffles were after installation. I've seen easy an 50 degree drop when I installed some baffles on one of my airplanes.

RE: Mini Temperature Guns! The "Hottest" Thing
 

Don't overlook the use of these to measure your covering iron. They work a lot faster and are more accurate than a pocket thermometer.

RE: Mini Temperature Guns! The "Hottest" Thing
 

Good point on the covering iron. One of those obvious things that I just never thought about. Thx.

RE: Mini Temperature Guns! The "Hottest" Thing
 

Works great on my sprint car tires

RE: Mini Temperature Guns! The "Hottest" Thing
 

<<...don't know the basics well and can't get the value of their new toy because they don't know what they're doing to begin with...>>

Well said, and that about sums it up. Gadgets are fun, and neat, but in most cases cannot compensate for a lack of knowledge. These temp guns were all the rage among some heli guys for a while. I have seen at least three newbies with mixtures so FUBAR the machine would barely fly; but they were getting the temp readings that good old so-and-so on the forum said they should be getting, so by God they were okay...:eek:

.

RE: Mini Temperature Guns! The "Hottest" Thing
 

So they were using the temp gun to set the fuel mixture?? Hmmm.

RE: Mini Temperature Guns! The "Hottest" Thing
 

No.

They had no clue how to set the fuel mixture (and in one case, he didn't even know you COULD adjust the mixture), but were dicking with the needles until the RayTek showed the temperature they were looking for.

I tried explaining to the first one about the difference between in-flight temps and what he was getting after landing, letting the blades spool down, etc., etc. At first I got an RCA dog look, then your basic dismissive body language since I wasn't saying what he wanted to hear.

The next two I simply watched, and was entertained... so, now that I think about it, those temp guns DO have a useful purpose when used on R/C aircraft.

.

RE: Mini Temperature Guns! The "Hottest" Thing
 

Maybe one day an engine manufacturer will bring out an engine with oxygen sensors in the intake and exhaust to check if the mixture is right just like a modern car.

RE: Mini Temperature Guns! The "Hottest" Thing
 

Wouldn't be hard to do, but I couldn't afford the engine!

RE: Mini Temperature Guns! The "Hottest" Thing
 

Here is a photo of one of the temp. sensors from Radio
Shack Works good around the house. Cost including battery and tax was $58.00
Going flying tomorrow let you know how I like it for use on model engines.

Good Flying

Lee