BillS

I would like to add heat to the glow plug to increase engine reliability from the occasional shut down. A 1600 mah NiCad cell will weigh about 1.5 oz. If The entire current capacity could be used the glow plug could be heated for approximately 1.5 hours which would be simple and cheap insurance against engine shut down. I somehow doubt if the plug would stay warm long enough to start the engine for anywhere near 1.5 hours.


Does anyone have any experience on how long glow plug heat could be expected to be hot enough to start an engine?


Thanks for any information.


Bill

greggles47

Is your plug going out an ongoing problem? How often does it happen?

Are you using a plug in the correct heat range for your usage?

You may find moving to a hotter plug or idle bar plug solves your problem without the added weight of an onboard glow circuit.

CLBetten

My Feedback: (16)

Another thing to consider is the fact that the glow plug will have a very short life if it's being powered at full voltage and being run at RPM where it normally stays "lit" without power.

TomCrump

Install a glow driver like this one from Electro Dynamics. http://www.electrodynam.com/store/GlowLite.shtml

They are easy to install, and very reliable. The unit has adjustable on/off points, to help insure a reliable engine run.

1QwkSport2.5r

Under most circumstances, I see on-board glow drivers as a band-aid for poor tuning, improper glow plug/fuel choice, or fuel tank setup. About the only time I would see it acceptable to use an on-board glow driver is for multi-cylinder engines and even then I'm wary of needing one.

To the OP: why do you feel you need an on-board glow system in place? Can you describe your situation/aircraft/engine setup?

TomCrump

I see onboard glow drivers as inexpensive insurance for expensive models.

That doesn't mean that I don't believe in proper tuning.

GREG DOE

Bill, Back in the mid 70's the rules for 1/4 Midget Racing (.15 size engines) stipulated that you must land with your engine running, or lose 1/2 point of your finishing score. I installed a nicad in my airplane to provide glo-heat. Tommy Baker saw my set up, and fixed his airplane at the Nats. Tommy went on to win first place with his setup. For my installation, I wired in a micro switch, that turned the battery off at high throttle, so only when I reduced throttle did I have glo-heat. I used the set up to start my engine too. The next year on board glo-heat was banned. Good luck, Greg

BillS

The airplane a Kougar and is neither expensive or sophisticated. Idling above 4,000 RPM to prevent uplink dead sticks just seems wrong.


After attempting to resolve high idle of 4,000 RPM or so and the occasional dead stick for several years using several prop sizes and a lot of test time:
APC 10x6,10x7,10x8,11x6
MA 10x6,10x7
MA G/F 3 Series
MA S-2 Seres
MA Schmitar
many different glow plugs currently an OS 4 stroke I have simply decided that a different approach is desirable. It took several months of thought to decide 1.5oz. of additional dead weight might be worth additional reliability.


If I ever get the engine to idle slightly under 3,000 RPM and not drop dead on the up line attention can easily be turned to testing without glow heat.


Thanks, everyone.

1QwkSport2.5r

What engine are you using that you cannot get to idle under 4,000rpm? Most engines should easily be idled down to 2,500rpm.

BillS

Super Tiger .45, made in Italy, Original bullet muffler with exhaust deflector

1QwkSport2.5r

How much nitro are you using? The Italian Super Tigres are designed for very little nitro. I haven't had any luck running more than 5% nitro without shimming the head. 5% nitro and a hot glow plug and they purr like kittens.

Rv7garage

My Feedback: (10)

Remember, it might be poor tuning causing the issue... or bad plumbing... or a bad / dirty carb. I've had poor plumbing drive me crazy before, and have seen carb gunk cause issues as well.

I like the SwitchGlo Pro drivers... since MPI stopped making my favorite unit

http://www.radicalrc.com/category/Gl...er-Onboard-375

I use 'em for starting my cowled multis.

CLBetten

My Feedback: (16)

There should be no reason to use onboard glow for an ST 45. Not to sound rude but that would be a Band-Aid for the real issue.

Rv7garage

My Feedback: (10)

Sometimes finding the real issue ain't easy

1QwkSport2.5r

I gotta go +1 with what CLBetten said. Super Tigre engines purr like kittens with the proper fuel, glow plug, fuel system, and proper tuning. If it doesn't run right in the aircraft, put it on the test stand with a known good fuel system. Easy way to find problems and fix them.

Rv7garage

My Feedback: (10)

Fair enough. I agree about the test stand, definitely. I finally broke down and got the PSP stand last winter; its a pleasure to use. Maybe all I mean is that some people just don't "get" plumbing, or the personality of carbs.

Problem's gotta be the carb; its hard to believe it could maintain 4K rpm with a plumbing issue.

And I'm in this philosophical camp, Tom summed it up

1QwkSport2.5r

I made my own version of a PSP stand. Except I used white oak, red birch, American black cherry, and brazilian ebony on mine instead of regular birch ply.

I have a heavy duty test stand built for firewall mounted engines too. That's rustic hickory.

If you can't tell, I love hardwood. I gave a buddy some African mahogany to use on his test bench.

Rv7garage

My Feedback: (10)

Wow, post a pic of it if you can- I'd love to see

BillS

5% and 10% has been used and the tank and pluming has ben changed at least once.

1QwkSport2.5r

Then something is amiss because there's no reason that engine won't idle below 4k.

stuntflyr

They need heat at idle, and the low nitro and hot plug are good recommendations, then tune the carb. ST carbs take a bit of tuning but I just set the low needle until I could get a good acceleration off idle. Many times I thought it was rich when it was lean, and the other way around. You've got to be close if you're flying the model now, a little time hunting for problems and getting it properly set and the engine will run fine.

There are some hot plugs from Hobby People, Thunderbolts I think, that C/L Stunt guys use in troublesome tuned pipe models that need heat to keep from shutting off in hard corners. Look at high heat ranges in all available plug manufacturers to see what's available.

A buddy uses glow heat on his Balsa USA SE5a with an ST 90, inverted mount, hard to get to, probably plumbed a bit wrong, hot plugs help, but deadsticking a detailed Scale model in the weeds is no fun. He has the glow heat for low power, super slow idle for assured stops without brakes on pavement, stays running in the pattern at low scale-like speeds and it is a good band aid for the flooding tank plumbing problem.

Chris...

stuntflyr

Double "RCU" post, what a forum website tragedy this site has become!

Chris...

1QwkSport2.5r

The only thing I'll add in regard to the ST carb is this - they aren't setup totally like typical 2-needle carbs in that you set the high speed first then set the idle mix for good transition. Being that ST. carbs have the midrange adjustment, you use that adjustment to alter the transition mixture and the idle needle for just that - the idle mixture. While it is a little bit of a catch-22, it's easy to set. Sometimes you have to tweak the idle mix a few times and adjust the midrange a few times to get it where the engine likes it. My S90 didn't throttle right (way rich) until it was well broke in with 2-3 gallons through it. In this time I had to adjust the spraybar so the fuel inlet nipple was pointing at the engines mounting lug. This leaned the midrange considerably. During the first 3 gallons of fuel, it would happily idle down to 2,500rpm however, regardless of spraybar position. The instructions to set the carburetor are found here on the left side of the screen about halfway down the list of FAQ's: http://www.supertigre.com/faq/product-faq.html#q22s

BillS

Glow heat
"How long can glow plug heat be expected to be hot enough to start an engine?" No one doubts that many can fine tune a Super Tigre Engine but success has been a problem for me.


I am attempting to understand setting the ST by solving the settings while glow heat is operational.




Bill

BillS

Just information
"How long will glow plug heat drive a plug?"


5500mah will heat a glow plug for one hour.
Radio Shack sells a "C" cell with 3500mah that weights 1.5 oz. that should drive a plug about 40 minutes.


Bill