How to get max rpm out of a tt 40
06-23-2011, 03:44 AM
#27
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RE: How to get max rpm out of a tt 40
ORIGINAL: GSJames
Mike: What do you use for lapping compound these days? In my CL Combat days, on the G21-35's we used automotive rubbing and/or polishing compound.
ORIGINAL: blindfaithnogod
the rod to the crank. it needs lapped in.
the rod to the crank. it needs lapped in.
06-23-2011, 08:09 AM
#28
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RE: How to get max rpm out of a tt 40
Hi!
Head shims are head gaskets!
Just different words for exact the same thing.
The TT .40 SE comes with a head gasket (shim) that is 0,4mm thick but that is too thick if you want to run on lower nitro contents or no nitro at all.
For 15% nitro or more it might be perfeckt.
I haven't tried my new TT yet but I have made my own 0,1mm alumium gaskets and put two in so well see what happens when I run my engine on 80/20 fuel.
Head shims are head gaskets!
Just different words for exact the same thing.
The TT .40 SE comes with a head gasket (shim) that is 0,4mm thick but that is too thick if you want to run on lower nitro contents or no nitro at all.
For 15% nitro or more it might be perfeckt.
I haven't tried my new TT yet but I have made my own 0,1mm alumium gaskets and put two in so well see what happens when I run my engine on 80/20 fuel.
06-23-2011, 12:55 PM
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RE: How to get max rpm out of a tt 40
I did some bench testing with a TT40 some years ago and found .012 to .014" HEAD to PISTON clearance worked best (highest rpm) with a 9x6 prop and 15% fuel. I think I ended up with two .004" shims in there.
09-01-2011, 11:43 AM
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RE: How to get max rpm out of a tt 40
I don't understand Please explain .004 + .004 = .008 how does this fit between .012 and .014. I am having trouble connecting the dots so to speak. Unless the the other .004 to .006 clearance was without any shims at all. Is that what you were saying??
ORIGINAL: PAINLESS
I did some bench testing with a TT40 some years ago and found .012 to .014" HEAD to PISTON clearance worked best (highest rpm) with a 9x6 prop and 15% fuel. I think I ended up with two .004" shims in there.
I did some bench testing with a TT40 some years ago and found .012 to .014" HEAD to PISTON clearance worked best (highest rpm) with a 9x6 prop and 15% fuel. I think I ended up with two .004" shims in there.
09-01-2011, 12:38 PM
#34
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RE: How to get max rpm out of a tt 40
Barry - yep, the rest of the clearance is in the stock fit with NO shim. It varies from engine to engine by a few thousandths of an inch, from what I can see.
I've had engines that would just about have zero clearance with no shims in place, others with several thousandths of clearance between the squish band on the head and the piston at TDC.
I've been running mine at .015 head to piston or thereabouts, might have to go down a little bit lower. That is, if I feel like messing with it. They all run pretty well at .015, I've been getting decent consistent runs there. It takes a whale of a lot of RPM difference to make up for flying, so practicing is probably time better spent instead of fooling with engines.
Break them in well, don't abuse them, and fly fly fly.
I've had engines that would just about have zero clearance with no shims in place, others with several thousandths of clearance between the squish band on the head and the piston at TDC.
I've been running mine at .015 head to piston or thereabouts, might have to go down a little bit lower. That is, if I feel like messing with it. They all run pretty well at .015, I've been getting decent consistent runs there. It takes a whale of a lot of RPM difference to make up for flying, so practicing is probably time better spent instead of fooling with engines.
Break them in well, don't abuse them, and fly fly fly.
09-01-2011, 01:55 PM
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RE: How to get max rpm out of a tt 40
Yes, I treat my Pro 40's just like I did my F1 engines. The fastest ones are only used on race day. I never do aerobatics with them and the slowest ones are my practice mule engines. And as you know it does make a difference. I have been accused of doing something illegal as my motors run so well. And not all 9x6 props are the same. I buy a dozen, balance them and them run them on a test motor. The ones that turn the fastest are used on race day the rest are practice and whatever. And as you said practice,practice, and more practice. One blown turn can cost 5 sec. or more on your time for that heat.
09-01-2011, 02:02 PM
#36
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RE: How to get max rpm out of a tt 40
Barry - around here, we provide propellers with registration at the races, and they're dyed different colors, so we can tell if folks are using the provided props. You are correct, there are differences, but this way everyone has the luck of the draw.
We also fly some 426, for those who want to do like you're suggesting - buy lots of props, sort through them, test run/test fly, etc. 424 is our low-key fun event, and it's been working out pretty well. This year attendance is a little down due to the economy, but last year we got as many as 28 people to a 424 race. So far this year it's been 14-16 people. The two-day race that KCRC throws is October 1-2, that one usually draws a few more long-distance folks because they can race for two days!
We also fly some 426, for those who want to do like you're suggesting - buy lots of props, sort through them, test run/test fly, etc. 424 is our low-key fun event, and it's been working out pretty well. This year attendance is a little down due to the economy, but last year we got as many as 28 people to a 424 race. So far this year it's been 14-16 people. The two-day race that KCRC throws is October 1-2, that one usually draws a few more long-distance folks because they can race for two days!
09-01-2011, 03:18 PM
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RE: How to get max rpm out of a tt 40
I've been running a Merlin 2016 Globee style plug for the Thunder Tiger Pro 40.
It seems to be good for an additional 100 to 200 rpms when compared to a conventional plug.
It seems to be good for an additional 100 to 200 rpms when compared to a conventional plug.
09-01-2011, 03:47 PM
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RE: How to get max rpm out of a tt 40
Yes, the 216 takes up, more room in the combustion chamber. It is like removing .004 worth of shims. If you have shimmed the engine already then a 216 will slow the motor down. If you haven't and are running where head shimming is not allowed the 216 is a great plug
09-01-2011, 07:38 PM
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RE: How to get max rpm out of a tt 40
I have never had a new tt 40 all my engines have come from % Bay used but when i get them i check first for end play they must have it then I run them rich with a 9x4 and fly them rich I dive the plane so it realy turns up and i dont weld the muffler i use the 6/32 rod with a spring so it has room to grow so it can be taken apart to see its stock And never race them at peak leave room to unload
I think my engines run great thats all i do and they keep getting faster
Duane
12V
MOKAN
I think my engines run great thats all i do and they keep getting faster
Duane
12V
MOKAN
09-02-2011, 09:31 AM
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RE: How to get max rpm out of a tt 40
But be sure to change out the main bearing if it isn't one of the newer ones with the non-metal retainer. Don't learn the hard way...like I did... [:@]
01-22-2015, 07:23 AM
#44
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Thunder Tiger Pro 40 used for racing.
What should the crankshaft endplay be set at ?
What is the best piston to head clearance for IndianaALTITUDE 750 feet and using 15% nitro.
What should the crankshaft endplay be set at ?
What is the best piston to head clearance for IndianaALTITUDE 750 feet and using 15% nitro.
03-24-2015, 07:06 PM
#45
Not mentioned are a few things legal to do anywhere.
1). use a cold plug - Odonnel car plug or Mcoy #9
2). Break in motor properly
- by this I mean after a shortened prop to break in on ground ( no more than 2 runs), take it to the sky and and continue to climb high and dive straight down to unload engine at peak rpms. This will set piston and sleeve to this wear pattern.
3). wrap needle adjustment area with fuel tubing to totally seal it from any leaks
I would also use a bubbles tank if legal, if not get the stock one totally secure and vibration proof. The less bubbles the better.
Also clean the flashing off the prop edges.
I also dont like running a spinner unless I have to.
If the engine is out of balance (which all are) and excess weight on the end of the crank in that spinner area, will magnify that out of balance even more.
These things alone will yield 200-330 rpms.
below are extra things that may not be legal in your area:
1).some have removed head shims, or changed them,
2).cut the low speed needle and cleared out throttle barrell area
3). the new baffles in muffler are terrible - remove
4). bubbless tank is a must
5). run an APC 8.8X8.75
And most important of all- fly smooth, low and avoid excess control surface inputs.
1). use a cold plug - Odonnel car plug or Mcoy #9
2). Break in motor properly
- by this I mean after a shortened prop to break in on ground ( no more than 2 runs), take it to the sky and and continue to climb high and dive straight down to unload engine at peak rpms. This will set piston and sleeve to this wear pattern.
3). wrap needle adjustment area with fuel tubing to totally seal it from any leaks
I would also use a bubbles tank if legal, if not get the stock one totally secure and vibration proof. The less bubbles the better.
Also clean the flashing off the prop edges.
I also dont like running a spinner unless I have to.
If the engine is out of balance (which all are) and excess weight on the end of the crank in that spinner area, will magnify that out of balance even more.
These things alone will yield 200-330 rpms.
below are extra things that may not be legal in your area:
1).some have removed head shims, or changed them,
2).cut the low speed needle and cleared out throttle barrell area
3). the new baffles in muffler are terrible - remove
4). bubbless tank is a must
5). run an APC 8.8X8.75
And most important of all- fly smooth, low and avoid excess control surface inputs.
03-25-2015, 02:15 AM
#46
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Not mentioned are a few things legal to do anywhere.
1). use a cold plug - Odonnel car plug or Mcoy #9
2). Break in motor properly
- by this I mean after a shortened prop to break in on ground ( no more than 2 runs), take it to the sky and and continue to climb high and dive straight down to unload engine at peak rpms. This will set piston and sleeve to this wear pattern.
3). wrap needle adjustment area with fuel tubing to totally seal it from any leaks
I would also use a bubbles tank if legal, if not get the stock one totally secure and vibration proof. The less bubbles the better.
Also clean the flashing off the prop edges.
I also dont like running a spinner unless I have to.
If the engine is out of balance (which all are) and excess weight on the end of the crank in that spinner area, will magnify that out of balance even more.
These things alone will yield 200-330 rpms.
below are extra things that may not be legal in your area:
1).some have removed head shims, or changed them,
2).cut the low speed needle and cleared out throttle barrell area
3). the new baffles in muffler are terrible - remove
4). bubbless tank is a must
5). run an APC 8.8X8.75
And most important of all- fly smooth, low and avoid excess control surface inputs.
1). use a cold plug - Odonnel car plug or Mcoy #9
2). Break in motor properly
- by this I mean after a shortened prop to break in on ground ( no more than 2 runs), take it to the sky and and continue to climb high and dive straight down to unload engine at peak rpms. This will set piston and sleeve to this wear pattern.
3). wrap needle adjustment area with fuel tubing to totally seal it from any leaks
I would also use a bubbles tank if legal, if not get the stock one totally secure and vibration proof. The less bubbles the better.
Also clean the flashing off the prop edges.
I also dont like running a spinner unless I have to.
If the engine is out of balance (which all are) and excess weight on the end of the crank in that spinner area, will magnify that out of balance even more.
These things alone will yield 200-330 rpms.
below are extra things that may not be legal in your area:
1).some have removed head shims, or changed them,
2).cut the low speed needle and cleared out throttle barrell area
3). the new baffles in muffler are terrible - remove
4). bubbless tank is a must
5). run an APC 8.8X8.75
And most important of all- fly smooth, low and avoid excess control surface inputs.
MFLOOD3800
Thank you so much for this good information. I'll put it to good use. Would you start with this prop size on a 2 pole pylon race?
our Sky Raiders slow down a lot in the turns, or should we make wider turns ?
Thank you for your help
03-25-2015, 04:54 AM
#47
I use this prop on a quicky simply because the front area is small enough to utilize the smaller prop and still be efficient. The sky raiders may have a bigger frontal area. Not sure what your elevation is either.
You just need to tach it on ground and find the prop that gets you close to 16,000, and then fly it and see who it turns.
As far as the turns being made wider, I like a tight turn as that is where most races will be run, especially on the last turn of the last lap.
You just need to tach it on ground and find the prop that gets you close to 16,000, and then fly it and see who it turns.
As far as the turns being made wider, I like a tight turn as that is where most races will be run, especially on the last turn of the last lap.
