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Old Jul 29, 2012, 09:58 PM
"My grandma wants to fly jets"
heychas's Avatar
Richmond, VA
Joined Feb 2008
468 Posts
LOLO,

That's a good idea. I think I was okay. I was measuring it form those red stickers which were between 105 and 110 mm. If that looks off from yours, please let me know!

My experience tends to agree w/ Pete... but why? Could the soft wheels slow it down that much? Do I need more cells? I haven't downloaded the esc data yet, but several test before hand indicated 70A/1600w (watts meter) to 80+A/1700+w (internal esc)... so I'm thinking I had correct power from that set-up.
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Old Jul 30, 2012, 02:20 AM
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Joined Dec 2010
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Heychas,

Ok your CG seems to be right but there are so many things...

-Make sure your ESC settings are right with the motor you are using so you will get the maximum of it. Use a power meter to check Amps, Watts, Volts, everything before you try to fly it.

[QUOTE= I have lite flight foam wheels which are small (1 1/2" front and 1 3/4" mains) that compress a lot from the weight. [/QUOTE]
Wheels shouldn't be a problem unless they are too soft and small. Use at least 1 3/4 nose and 2" main.

-I don't think the plane will take off if it doesn't have enough speed but don't pull the elevator too hard if you think that was the case(use expo on elevator)....

-Take off against the wind.

-If you have a short runway Flaps will help on take off, etc.
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Last edited by LOLO77; Jul 30, 2012 at 02:45 AM. Reason: adding thoughts
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Old Jul 30, 2012, 04:32 PM
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San Antonio, Tx
Joined Dec 2006
20 Posts
Heychas
I do believe you did not achieve enough speed on grass field takeoff. CG could also add to it. I flew mine off of a paved runway and needed all the speed i could get for good takeoff. These little T-45's weight a ton for thier size. Mine was a 2 3s 5000mas in series running a RClander 90mm metal fan. After the crash i found 1 cell gave out which was a 5cell takeoff and not enogh power and speed.

Pete
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Old Jul 30, 2012, 08:01 PM
"My grandma wants to fly jets"
heychas's Avatar
Richmond, VA
Joined Feb 2008
468 Posts
Lolo & Pete,

Thanks guys! Sorry Pete about your bad battery on T/O... ouch!

Great idea LOLO. I think I'll put my firmer stock wheels back on rather than my super soft wheels. And there was no wind that day which was the first time all year! And the flaps would have been a good idea. I normally do that but others thought they weren't necessary. And I'll try that longer and smoother runway.

Thanks a bunch for these great idea!
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Old Aug 01, 2012, 03:49 AM
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United Kingdom, England, Nantwich
Joined Jan 2012
255 Posts
Quote:
Originally Posted by nerv View Post
Hi Hixxer,
I wish you live closer or at least in US....I want a new wing because my old wing does not look pretty after all the repairs on the gear mount.
Shipping to the US is not a problem, it will arrive in one piece when I pack it.

Just a reminder of what is for sale:
Wing - As new, wheel well covering trimmed and that is all thats been done.
All control surfaces - as new
Horizontal stab - as new
Canopy - as new
Cockpit interior - as new, but instrument panel stickers removed
And everything else apart from anything fiberglass (all busted in one way or another)
I also have these oleos - https://www.scaleflying.com/T-45-Lan...ts_p_1847.html
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Old Aug 07, 2012, 12:03 PM
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Irvine, Calif USA
Joined Feb 1999
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Originally Posted by vengame View Post
short flight this morning
Vengame, nice flight ! A bientot HWH
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Old Aug 07, 2012, 12:11 PM
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Irvine, Calif USA
Joined Feb 1999
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Quote:
Originally Posted by heychas View Post
... It immediately stalled, rolled over, and crashed into the earth creating extensive damage to the nose and power system. ...
Hi, Sorry to hear that

Overweight, a bit underpowered, uneven runway = not enough speed ?

I would have used a lighter battery for the maiden ... that might have prevented the stall. Go around a few times, trim her out and land. You can use the heavier batt later.

Make sure you use the correct CG posted in the first post of this thread. That will make a difference in getting the thing off the ground.
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Old Aug 07, 2012, 12:13 PM
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Irvine, Calif USA
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Quote:
Originally Posted by LOLO77 View Post
...here is the video of my CMP T45 now on Stumax fan with 6s 5000mah... I took some weight out but still a little heavy. With 3700mah will be lighter and will fly a lot better as Herb suggested. ...
Nice LoLo Yes lighter flies better, and the Stu fan is not a lightweight either from what I remember.
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Old Aug 11, 2012, 06:17 AM
"My grandma wants to fly jets"
heychas's Avatar
Richmond, VA
Joined Feb 2008
468 Posts
Thanks for your thoughts Herb! I hadn't thought about using a lighter battery because I thought I was behaving well by using a 6s 4500 battery. How light do I dare go? 6s 3700? 3000? Here are some nano-tech battery options... is 25c to wimpy?

6s 4500 35c 676g (1.49 lbs) [what I have]
6s 3300 35c 522g (1.15 lbs)
6s 3300 25c 489g (1.08 lbs)
6s 3000 25c 447g (.99 lbs)

Pulling 70A = 1166 mah/min at WOT so a 80% of a 3000mah = 2400mah or about 2 min of flight time.

I appreciate someone sharing about wing cube loading. I've had a chance to look at it, and it seems to better adjust for model size than straight wing loading. Check out these EDFs I have compared to the industry standard:

Airplane Wing Loading vs Wing Cube Loading
Phase3 F-16: 17.7 vs 15.2
Starfire: 34.1 vs 20.0
CMP T-45: 38.2 vs 23.8
GP Evader: 23.1 vs 26.2
Efilte Bae Hawk: 32.2 vs 26.9

Typical WCL Values for Models
Slow flyers and thermal gliders: under 4
Trainers, park flyers, 3D: 5 to 7
General sport and scale aerobatics: 7 to 10
Sport and scale models: 10 to 13
Warbirds and racers: 13 and over

You can see the GP Evader seems pretty safe w/ a wing loading of 23.1. But in reality its cube loading is 26.2 which helps explain why you see these things falling out of the sky all the time on that thread. The CMP T-45 seems pretty dangerous with loading of 38.2 but its cube loading is more tame at 23.8... although it is still something to be respected. I know Tim (product designer) flies his Evader at WOT the whole flight. I wonder if anything over 25 or 26 WCL needs to be flown like that to prevent tip stalls?
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Last edited by heychas; Aug 11, 2012 at 07:43 AM.
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Old Aug 11, 2012, 12:16 PM
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Irvine, Calif USA
Joined Feb 1999
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The CMP Hawk / T-45 wingloading can be quite high ... It can't be flown too slow or it will tipstall.

It is a heavy airframe with a small wing, esp. the fuse is heavy.

That is why I recommend keeping it LIGHT and use a lightweight battery, like 3300 to 4000 mAh 6S, at least initially.

You can always buy multiple packs and fly all day, that is what I do. I don't ever charge anything at the field.

Unless things have changed lately, most nanotecs are overhyped junk. Everybody at my field has had the same experience, and we fly all year long.

I would go with a Gens Ace 25-30C pack, I have tons of those and they are better quality (plus you get them in three days) :

http://www.hobbypartz.com/gensace30c1.html
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Old Aug 13, 2012, 09:56 AM
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Joined Dec 2010
31 Posts
Better video of my T45

Ok here is a really good video of my T45 (a good friend made it for me). I took the stumax fan out and I put a wemotec w/same motor(ARC 36 75 1) on 7S. On my fight against the weight I took some stuff out... the BEC, extra battery, brake system, lights system, pilots figure, etc, etc, etc... Still a little heavy due to some mods like fiberglassed wing, reinforsements, etc, but its flyable, no bad flight time, 4 min 30 sec on my timer with throttle managment having 30% left on my batteries. Enjoy.



T-45 Goshawk RC EDF Jet 3000w (5 min 18 sec)
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Old Aug 13, 2012, 11:10 AM
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United States, TX, Grand Prairie
Joined Nov 2005
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Quote:
Originally Posted by LOLO77 View Post
Ok here is a really good video of my T45 (a good friend made it for me). I took the stumax fan out and I put a wemotec w/same motor(ARC 36 75 1) on 7S. On my fight against the weight I took some stuff out... the BEC, extra battery, brake system, lights system, pilots figure, etc, etc, etc... Still a little heavy due to some mods like fiberglassed wing, reinforsements, etc, but its flyable, no bad flight time, 4 min 30 sec on my timer with throttle managment having 30% left on my batteries. Enjoy.



http://www.youtube.com/watch?v=baEkc0oChD8&feature=plcp
That wemo\arc combo is 8s but it flew tops on 7s...really nice and it seemed from clouds that it was on the step a good portion of flight...

What landing gear did you use? Really tough

Regards
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Old Aug 13, 2012, 11:18 AM
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Herb's Avatar
Irvine, Calif USA
Joined Feb 1999
12,158 Posts
Excellent video LoLo, one of the best !

Scale takeoff, very nice flight, perfect landing ... yours is now one more example of how this thing should be set up and flown.
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Old Aug 13, 2012, 01:16 PM
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Quote:
Originally Posted by erh7771 View Post
That wemo\arc combo is 8s but it flew tops on 7s...really nice and it seemed from clouds that it was on the step a good portion of flight...

What landing gear did you use? Really tough

Regards
Ok, I used 7S because I didn't want to go too xtreme with the power. 7S more than enough. My landing gear... eflite 25 46 with tamjets struts and wheels. I modified the wheels a little. I put low bouncing tires from Dubro wheels on the mains.The original tire is too hard and I had a lot of kangu-ladings at the beginning... They are a little bit heavier but effective. I still looking for the perfect wheels.
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Old Aug 13, 2012, 01:26 PM
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Thanks Herb.Your Forum its very instruccional and helpful. Now it's getting better. This plane is just amazing. I love it. Thanks for your help.
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