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Old Sep 02, 2006, 07:28 PM
Old F-4 Crewchief
fuzzyhead's Avatar
Schertz, Texas, United States
Joined May 2004
1,280 Posts
Finally got a windless day for the maiden. I was supposed to be tiling the bathroom floor but just had to put this puppy in the air. Considering my first TM 400 experience I was a bit edgy. Got airborne in about 20 feet. A steady climb out with a slight roll to the left. Easily trimmed out. Need to add a little weight to the nose. Was able to over trim for level flight. Anything above half throttle she would climb. I was surprised how stable it was at slow speeds. Made several full stop landings. Uneventful. Great all around flyer. Looking forward to more stick time with this one. Now to finish the floor.
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Last edited by fuzzyhead; Sep 02, 2006 at 09:44 PM.
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Old Apr 01, 2007, 07:49 AM
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Joined Aug 2004
337 Posts
Mine also has a strong tendency to climb under power, tried putting in downthrust but didnt make much difference. COG is bang on where most people put it - just at the rear cabane strut - whats the answer to this ?? It is also at target weight, and I use a 3s Lipo and CK outrunner b/less motor
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Old Apr 01, 2007, 08:17 AM
Lori, hey, you're home early
CarreraGTSCS's Avatar
United States, NJ, Trenton
Joined Jan 2004
9,130 Posts
flybyday-- It sounds like a case of more power that was originally intended for the airframe. I have a geared brushless in mine but I took out the lipo's and put in 1100mah nimh's as it was a bit floaty at the lipo weight. In any event, you probably already know that in full size aircraft the altitude is controlled by the throttle setting rather than the elevator. Maybe you're emulating scale.

When you say "a strong tendency to climb under power" do you mean climb or is it pitching up?

Mike
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Old Apr 01, 2007, 01:53 PM
Dance the skies...
Tom Frank's Avatar
United States, MA, Walpole
Joined Dec 2003
17,980 Posts
Quote:
Originally Posted by flybyday
Mine also has a strong tendency to climb under power, tried putting in downthrust but didnt make much difference. COG is bang on where most people put it - just at the rear cabane strut - whats the answer to this ?? It is also at target weight, and I use a 3s Lipo and CK outrunner b/less motor
You need more down thrust. Alternatively, if you have a computer radio, you can dial in a VERY TINY bit of proportional down elevator slaved to the throttle channel stick position (increase down elevator as throttle stick advances). This is tricky to get right, so I'd opt for more downthrust.
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Old Apr 01, 2007, 02:54 PM
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Joined Aug 2004
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I did modify it to give a LOT of downthrust, but it did not help. The effect is more like the nose dropping /nodding when power is reduced to very little /none. I then have to put in loads of up elevator in order to hold it level, increasing power then causes it to climb. I have a lot of electric models, and have been flying for many years, and this one just does not feel right. I have removed the down thrust, and await a clm day to retest it. I wonder if it may be slihtly nose heavy ?
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Old Apr 01, 2007, 03:12 PM
Doing it in the Lateral Axis
modfly's Avatar
USA, OH, Akron
Joined Dec 2006
15,360 Posts
Tm-400. AUW 17.80oz.

Hi everyone..Read most of this thread and did not see any flight video of the TM-400 or did I miss it somewhere? Well, here is a TM-400 video......http://www.rcgroups.com/forums/showthread.php?t=655491
I mounted my TP1320 lipo a little different than what I have seen here.
Would be intrested in your guys AUW.. mine is 17.80oz.
rob
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Last edited by modfly; Apr 01, 2007 at 03:22 PM.
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Old Apr 01, 2007, 03:56 PM
Dance the skies...
Tom Frank's Avatar
United States, MA, Walpole
Joined Dec 2003
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Quote:
Originally Posted by flybyday
I did modify it to give a LOT of downthrust, but it did not help. The effect is more like the nose dropping /nodding when power is reduced to very little /none. I then have to put in loads of up elevator in order to hold it level, increasing power then causes it to climb. I have a lot of electric models, and have been flying for many years, and this one just does not feel right. I have removed the down thrust, and await a clm day to retest it. I wonder if it may be slihtly nose heavy ?
When you said it didn't help, I thought you meant it still climbed under power. If I understand what you said, the model dives when power is applied and you have to add in up elevator to keep it level? This would indicate too much down thrust. Did you try different amounts... there should be a reasonably good point where the increased lift from extra speed at higher throttle pretty well offsets the downward pull from the increased thrust. It's not likely to work perfectly at all speeds with a light wing loading and fairly high lift airfoil like the TM has.

I use an outrunner and 3S lipos in mine, with about 1 deg. right and 1 deg. down thrust. I still get a little climbing at higher throttle settings, but I fly mostly in the 1/3 to 1/2 throttle points fairly scale-like, and only apply higher throttle when I'm doing some mild aerobatics, most of which involve some climbing anyway, so I just live with it! .

The perfect balance point for mine is at the front edge of the rear inner cabane strut. Good luck.
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Old Apr 01, 2007, 04:04 PM
The figure "9" Specialist
aeronca's Avatar
A Barrier Island in New Jersey, USA
Joined Oct 2003
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modfly,

I enjoyed your entire video. Thanks for sharing it! I can't give you my all up weight because I'm nowhere near done yet but, if like most of the rest of my fleet, it will be on the "heavy" side - LOL!

Aeronca
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Old Apr 01, 2007, 04:42 PM
Doing it in the Lateral Axis
modfly's Avatar
USA, OH, Akron
Joined Dec 2006
15,360 Posts
Aeronca..your quite welcome! My Daugter KAT shot the video. I tried to build my moth lite as I wanted it to fly slow. Contrary to what most people want I guess. I have a DX6 in mine which allows me to program how much current to the motor at WOT I have it set for 50% which gives me ample power. I use a SKYFLY 380 motor in mine. Ridiculous as that sounds.
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Old Apr 01, 2007, 05:13 PM
"Free crash instruction"
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long island N.Y.
Joined Jan 2004
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Yeah the warm weather has people out flying
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Old Apr 01, 2007, 05:29 PM
Doing it in the Lateral Axis
modfly's Avatar
USA, OH, Akron
Joined Dec 2006
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Not here..the wind is a blowin.
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Old Apr 01, 2007, 06:20 PM
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Joined Aug 2004
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Quote:
Originally Posted by Tom Frank
When you said it didn't help, I thought you meant it still climbed under power. If I understand what you said, the model dives when power is applied and you have to add in up elevator to keep it level? This would indicate too much down thrust. Did you try different amounts... there should be a reasonably good point where the increased lift from extra speed at higher throttle pretty well offsets the downward pull from the increased thrust. It's not likely to work perfectly at all speeds with a light wing loading and fairly high lift airfoil like the TM has.

I use an outrunner and 3S lipos in mine, with about 1 deg. right and 1 deg. down thrust. I still get a little climbing at higher throttle settings, but I fly mostly in the 1/3 to 1/2 throttle points fairly scale-like, and only apply higher throttle when I'm doing some mild aerobatics, most of which involve some climbing anyway, so I just live with it! .

The perfect balance point for mine is at the front edge of the rear inner cabane strut. Good luck.
No I did not say it dived when underpower, it climbs, and when the throttle is pulled back, it slows very quickly and drops it nose, requiring a lot of elevator to keep it flying
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Old Apr 01, 2007, 06:33 PM
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Jim Mayer's Avatar
Bensenville, Ill. United States
Joined Nov 2003
627 Posts
Anybody on this thread make a replacement cowl for the TM400 using the wooden plug and heat shrinking a plastic cup or bottle over the plug? If so what did you use?

Jim...
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Old Apr 03, 2007, 01:19 PM
Doing it in the Lateral Axis
modfly's Avatar
USA, OH, Akron
Joined Dec 2006
15,360 Posts
Hi everyone..I thought people here may want to see a alternate Lipo mount setup that could be useful. I'm going to post a link to a TM-400 that is outside this thread. Not trying to hijack this thread...but rather include the information for this thread. Some may find the info useful. Smooth Spanky seemed to think it was interesting. Hey Smooth, get a new moth built yet?
http://www.rcgroups.com/forums/showthread.php?t=655501
If anyone finds this objectionable, let me know and I will remove the link.
rob
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Last edited by modfly; Apr 03, 2007 at 01:28 PM.
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Old Apr 03, 2007, 01:37 PM
Dance the skies...
Tom Frank's Avatar
United States, MA, Walpole
Joined Dec 2003
17,980 Posts
Quote:
Originally Posted by flybyday
No I did not say it dived when underpower, it climbs, and when the throttle is pulled back, it slows very quickly and drops it nose, requiring a lot of elevator to keep it flying
That is sounding like it's nose heavy. Is your CG as I mentioned? Mine flies very slow, and has a gentle gliding descent on a dead stick landing, all without applying any up elevator.
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