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Jan 17, 2013, 07:20 PM
Registered User
bsfixit's Avatar
Question

Thunder Tiger .40 glow to electric question


I was given, by my dad, an older Thunder Tiger trainer plane that had a seized .40 nitro on it.
For my birthday last year, my dad gave me This:http://www.headsuprc.com/servlet/the...h-04%29/Detail
And the rest of the gear to power it. 100 amp opto ESC 6S lipo...

I flew it for the first time a month or so ago.. It flew great, plenty of power of course,
balance was spot on.. I came in for a landing due to a slow roll to the right or left. I didnt think the landing was too hard.. The motor flew off, taking the firewall and connected front wheel with it. I plan on repairing it... Does anyone think the motor and lipo weight are just a bit too much for this airframe? Any suggestions on how to beef up the front airframe/firewall? Or should I just look for another platform for this electric combo?
video of the first flight is here
Thunder Tiger Maiden (4 min 1 sec)

Thanks in advance....
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Jan 18, 2013, 01:12 AM
Registered User
scirocco's Avatar
A Thunder Tiger GP42 is 345g with a muffler, so if the model is balancing OK it's hard to call the motor too heavy - presumably a glow the same weight would have broken off in that crash too - I'm afraid from the video that calling it a landing might be a bit generous. And you said it glided almost too well which suggests its not that overly heavy all up.

If it's a clean break, fix the sucker. You've got all the power you need and then some, and the motor should be running nice and cool. Although I'd suggest trying a 13x10 2 blade - it'll still have more thrust than you need but has a more realistic pitch speed for your airframe.

Don't worry about the motor saying .80 on the label. If its weight works OK in your model to balance, and is heavy enough to handle the power, and Kv, voltage and prop size work well together, just call it a Firepower Skylark2.
Jan 18, 2013, 09:11 AM
Registered User
bsfixit's Avatar
LOL yeah I guess it wasn't really a "landing" Thanks for the reply
Jan 18, 2013, 09:42 AM
Hobby King Hater
Kimber's Avatar
Even though you have the motor, it is an over kill. It would be better to
go with a 40 or 46 motor and that way you could use a larger battery,
longer flight times. 60a ESC, more weight savings. And you could
use a smaller diameter prop for better clearance.

We have a 60 on an eight lb Cub and it is grossly over powered.
We run a 13/5 on 5s, 5000mah with flights over ten minutes and
plenty of reserve. Pulling just over 700w/
Jan 18, 2013, 09:52 AM
Registered User
bsfixit's Avatar
I see your point, perhaps with a Federal refund this year I can get a smaller setup, and use the .80 setup on a fiberglass acrobatic I have. It needs some work, but its all glassed.. even the wing. I know the .80 would give that plane unlimited vertical..
Jan 18, 2013, 03:23 PM
Redacted per NSA "suggestion"
dedStik's Avatar
I did a Great Planes Trainer .40 last year that I just maidened a few weeks ago. It's got a Turnigy G46 670kv a 60 amp esc and I'm running a 4S 5000 mAh pack. It gives 500 watts at WOT and only pulls a bit over 30 amps.
Jan 18, 2013, 03:48 PM
Registered User
scirocco's Avatar
Quote:
Originally Posted by Kimber
Even though you have the motor, it is an over kill. It would be better to
go with a 40 or 46 motor and that way you could use a larger battery,
longer flight times. 60a ESC, more weight savings. And you could
use a smaller diameter prop for better clearance.

We have a 60 on an eight lb Cub and it is grossly over powered.
We run a 13/5 on 5s, 5000mah with flights over ten minutes and
plenty of reserve. Pulling just over 700w/
It's only overkill if your combination of Kv prop and cells makes it so. Kv=400, 6S, 13" prop is pretty reasonable for a 40ish model, using about the same power as a Power 46 on 4S with the same prop.

If the model needs a lot of weight up front to balance, there's no problem with running a big motor understressed, ie with fewer cells or a smaller prop. And while you could go with a smaller motor and bigger pack, because of the moment arms for the pack and motor, that will usually end up heavier overall - to maintain cg you have to add more pack weight closer to the cg than you save in the motor further from the cg.

If it was nose heavy - different story - ditch that motor in a heartbeat
Jan 20, 2013, 02:28 PM
Registered User
bsfixit's Avatar
Another plus of a balanced plane with more weight and power, I should be able to fly in higher winds, 10-15 mph are common in Florida.


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