Turbo plugs

I use Kamtechnik heads on my TD 049 engines. I fly in weather between 10 deg C and 40 deg C. My fuel is always 55 meth, 25 nitro, 20 Castor. I use the higher Nitro not for power but it seems to give me a much wider power band on the needle. the needle is not quite as touchy. I tried OS P6 and P8 turbo plugs and found they didnt run and start as well as a P4 plug. that said, I dont use OS plugs anymore as I have found they dont from my experience justify their extra cost. I have found the much cheaper brand medium hot turbo plugs work well for me and if I dont rev the brains out of the engine they last quite well. You say you are having inconsistancy, but what is inconsistant, starting, needle settings, running during flight, running from one flight to the next on the same needle settings. It may not be the plugs that are the problem. I find each of my engines is different and they all tune a bit differently. Some go harder than others etc. I use either Kamtechnik heads with medium hot turbo plugs or I use the standard Cox Plug/head. I find both work well, but the tune charachteristics change with the different heads and so does the performance

Yabby wrote:I use Kamtechnik heads on my TD 049 engines. I fly in weather between 10 deg C and 40 deg C.  My fuel is always 55 meth, 25 nitro, 20 Castor.  I use the higher Nitro not for power but it seems to give me a much wider power band on the needle. the needle is not quite as touchy. I tried OS P6 and P8 turbo plugs and found they didnt run and start as well as a P4 plug. that said, I dont use OS plugs anymore as I have found they dont from my experience justify their extra cost. I have found the much cheaper brand medium hot turbo plugs work well for me and if I dont rev the brains out of the engine they last quite well.  You say you are having inconsistancy, but what is inconsistant, starting, needle settings, running during flight, running from one flight to the next on the same needle settings.  It may not be the plugs that are the problem. I find each of my engines is different and they all tune a bit differently. Some go harder than others etc. I use either Kamtechnik heads with medium hot turbo plugs or I use the standard Cox Plug/head. I find both work well, but the tune charachteristics change with the different heads and so does the performance

Where do I order those cheeper plugs from?

Yabby wrote:I use Kamtechnik heads on my TD 049 engines. I fly in weather between 10 deg C and 40 deg C.  My fuel is always 55 meth, 25 nitro, 20 Castor.  I use the higher Nitro not for power but it seems to give me a much wider power band on the needle. the needle is not quite as touchy. I tried OS P6 and P8 turbo plugs and found they didnt run and start as well as a P4 plug. that said, I dont use OS plugs anymore as I have found they dont from my experience justify their extra cost. I have found the much cheaper brand medium hot turbo plugs work well for me and if I dont rev the brains out of the engine they last quite well.  You say you are having inconsistancy, but what is inconsistant, starting, needle settings, running during flight, running from one flight to the next on the same needle settings.  It may not be the plugs that are the problem. I find each of my engines is different and they all tune a bit differently. Some go harder than others etc. I use either Kamtechnik heads with medium hot turbo plugs or I use the standard Cox Plug/head. I find both work well, but the tune charachteristics change with the different heads and so does the performance

Yabby, I just tried to answer your questions but the whole post vanished. I am blind in one eye and have partial vision in the other. the background and text are shades of grey. I have to use a big magnifier and type with other hand. it aint easy.

Yabby wrote:I use Kamtechnik heads on my TD 049 engines. I fly in weather between 10 deg C and 40 deg C.  My fuel is always 55 meth, 25 nitro, 20 Castor.  I use the higher Nitro not for power but it seems to give me a much wider power band on the needle. the needle is not quite as touchy. I tried OS P6 and P8 turbo plugs and found they didnt run and start as well as a P4 plug. that said, I dont use OS plugs anymore as I have found they dont from my experience justify their extra cost. I have found the much cheaper brand medium hot turbo plugs work well for me and if I dont rev the brains out of the engine they last quite well.  You say you are having inconsistancy, but what is inconsistant, starting, needle settings, running during flight, running from one flight to the next on the same needle settings.  It may not be the plugs that are the problem. I find each of my engines is different and they all tune a bit differently. Some go harder than others etc. I use either Kamtechnik heads with medium hot turbo plugs or I use the standard Cox Plug/head. I find both work well, but the tune charachteristics change with the different heads and so does the performance

I am test bench running one engine that is a great runner, always on the same 20% 20% fuel with a 6x3 master air screw prop to load it down. I have basically four heads of different compression ratios. The os p4 plug seems best so far. The last test session blew my mind when from one day to the next i got more than a 3000 rpm difference with the bad run not wanting to needle right. It just occurred to me that I have two p4 plugs. They look the same and I might be swapping them with out realizing it. I will isolate the one from the bad run and test again. That plug may have been messing with me the whole time.

You might have found the problem with the two different plugs. 3,000 RPM is a very big difference. Have you tried a 5 x 3 propellor? though it sounds like one of the plugs is the problem.

I order my cheaper Turbo plugs by searching the internet in Australia as shipping international is a killer. I find different Oz based hobby places have different brand plugs out cheap at times and I get a number of them when I can. Turbo plugs are used heavily by the Nitro RC Car people. they tend to use plugs in the 3 and 4 range which I have found work well for me. Some of the cheap plugs have let me down, b ut aat $12 Oz each compared to $20+ each for OS plugs I take the chance.

Yabby wrote:You might have found the problem with the two different plugs. 3,000 RPM is a very big difference. Have you tried a 5 x 3 propellor? though it sounds like one of the plugs is the problem.

Yabby, I was able to separate the plugs so I went out to test. It was terrible. As soon as it started it went to 15700 rpm, then started to four stroke. It wouldnt tune out, then the best I could get was 13500. Then it also started shutting down before the fuel was gone. After it shuts down I can smell the castor. Its hot.I am going to post a pic of a cox turbo head and also the testors turbo head.


I have real good luck with the Mecoa heads and I think im going to collect more of them and scrap this project.

Is the engine fully run in? I never use a Kamtechnik head on an engine till its run in. I have never used a Testors head so no ideas there. Sounds like its running really lean to get that hot or isnt run in. Have you tried using a standard Cox head to see how it goes and 5 x 3 propellor. I use 3 head gaskets under a kamtechnik head. I start with five or six and run the engine removing gaskets till I get the sweet spot for that engine. But 3 seems to be about the average. Different engines setup differently. Never change a Turbo plug or Plug/head whilst the engine is hot and has expanded. Wait for it to cool first.