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Old Mar 28, 2007, 07:37 AM
gpw
“There’s no place like Foam”
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United States, LA, New Orleans
Joined Jul 2002
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Spring , Many Thanks for the wonderful site !!!!!... certainly enough interesting planes to while away those rainy/windy days ... COOL !!!!
Glad you're having a good time !!!
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Old Mar 28, 2007, 07:43 AM
treefinder
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SE MI
Joined Oct 2004
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fms setup

If you need any help with the fms setup, give me a shout. I'll be offline a while, though, gotta go help a guy build a bridge (prop for Easter @ church)
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Old Mar 28, 2007, 07:47 AM
gpw
“There’s no place like Foam”
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United States, LA, New Orleans
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Great !!! Thanks, may have to consult you ... our resident computer genius (MS) is still down with sinus surgery recovery ... Aargh !!!
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Old Mar 28, 2007, 08:52 AM
Use whatcha got!
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Metairie, LA
Joined Sep 2000
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I haven't gotten into the FMS creation of things, but I'm sure someone out there could do it for us...

Can't wait to see an FMS UFO :P

gpw - back to work on Monday, I *think* the doc is going to clear me to work on Monday so I'll be on the westbank sometime next week. Possibly/Probably going flying on Saturday or Sunday of this week... startin to twitch

-ms
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Old Mar 28, 2007, 08:56 AM
Look outside the Square
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Gosford, Australia
Joined Jan 2006
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Great to see ya back MS. . If the thumbs are twitching, and thinking about work, your definately on the mend. You Beauty !!!!!!

Box
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Old Mar 28, 2007, 02:48 PM
gpw
“There’s no place like Foam”
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United States, LA, New Orleans
Joined Jul 2002
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Yippee !!! We know you're ready ... lets hope the weather holds out ... Got a new site to tell you about ... Bucktown ... right next to where the levee's failed...big open site far enough away from the water to make it safe , a big levee right behind for slope soaring ... and on your side of the United States...
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Old Mar 28, 2007, 06:37 PM
low tech high tech
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Southern Vermont
Joined Feb 2007
3,028 Posts
GPW, I actually found Trainer One and this thread because I had "flown" Gary Gunnerson's virtual model of your design on FMS . . . and really liked it. I've read most of the early posts here and am starting to get the gear and materials together to build one. I will have to use a Nimh battery pack though, but I'm hopeful that will be possible for trainer level performance with a 600 mah pack.

I tried out the model on MotoCalc program as well while I'm waiting, using the Jameco version of the j250. I used Jameco's catalog specs for the motor. But when I tried out the simulator it reported that the prop was turning somewhere between 25,000 and 30,000 rpm with the 3x3 prop, and the prop was stalled throughout the speed range.

I must be doing something wrong, unless it flies with a stalled prop at amazing rpms and I wonder if any of the motor gurus out there can show me where I've gone wrong. Or is it accurate, and that is really how the motor runs and flies? I'm thinking the prop specs might be the key to the problem, maybe?

The motor specs worked out to :

Motor Constant 4166 RPM/volt
No Load Current .363
Resistance 0.203

The program worked the resistance and motor constant out from the catalog (Jameco Datasheet) values:

Nominal Voltage 1.2V
Free Running RPM 4692
Current at Max Efficiency 1.51
No Load Current 0.363

I know the plane flies great as a trainer with the motor, so I just wonder what's wrong with the simulation?

Thanks for making available such a wonderful trainer.

Lived in Covington awhile ago.
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Old Mar 28, 2007, 08:54 PM
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United States, HI, Kapolei
Joined Jan 2007
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flight report........
28mar07 2150hrs maiden (test flight)t-1.......
yipeeeeeeee!!!! finally it flew....
replaced motor from and old plane(hobbico sport flier) and replaced lipos with 350 5cell nimh, replaced esc to c35 mini esc.
i was ready to give up on the whole thing but then decided to try it one last time.
gave it a toss and 1/2 throttle and it started to nose down, gave it 3/4 and it picked right up.....gitty at the moment so i decided to give it full and it started to go up....extra gitty by now i dediced i need to turn before i hit the playground, lo and behold no reaction......rudder inoperable..... so..brought it down back to 1/2 hoping to slow it before it hits something..too late..it just glided and i ended up dorking the nose. no biggie it's fixed and ready for the real flight tomorrow and i will double,triple check all connections before flight.
thanks everyone, hope is not lost, i maybe able to learn how to fly....
btw i think i have a 3 in prop on it. would going to a 4 or maybe bigger let me ease up on the throttle and maybe use 1/4 instead of 3/4 to get it going?
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Old Mar 28, 2007, 09:22 PM
treefinder
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SE MI
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smkn and vtdiy: I'm running a jameco J250 w/4.2x2 prop, Hobbico 8/4v 850mah pack and she flies just fine. climbs well, floats at part throttle. I thought the relatively heavy pack might be a problem, but it hasn't and they only cost $5.57 at Tower. Only using the 4.2 prop cause the local hobby store didn't have any 3 inchers.
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Old Mar 28, 2007, 09:33 PM
treefinder
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SE MI
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also forgot to mention I'm flying out of a 20 acre alfalfa field, so do all hand launches. Start at full throttle, throw it pretty much straight ahead. It dips a little then gains speed and climbs. throttle back at 30 ft or so and start experimenting. Unfortunately all my landings have been 1 point so far. Trying to learn to flare , but can't roll, so come in and nose over. That's where the pusher is great - no broken props.
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Old Mar 29, 2007, 07:12 AM
gpw
“There’s no place like Foam”
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The T-1 was never designed as a model of efficiency.. just a simple self-righting trainer with an extremely cheap motor ...Better motors would improve performance (climb/speed) but are more expensive not as simple as the J250... The 4x2 works fine , and a number of aftermarket props the same size work well too ... we use 7cell 1ooomah Nimh packs all the time , no problems and actually a little more power than the 2s lipos ...easier to balance the T-1 too ...

Simulations ... seem not to cover ALL the possibilities , but we don't argue about that ...
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Old Mar 29, 2007, 11:34 AM
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United States, HI, Kapolei
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i love this plane!!!!great for me. i actually fluew and lasted more than 20 seconds in the air until i dorked it again.
easy to build easy to fly and it really fixes itself as soon as i release the controls.
thanks gpw and everyone for all the advice.
time to print and cut.
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Old Mar 29, 2007, 01:49 PM
Tinkerer
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RI
Joined May 2005
184 Posts
Quote:
Originally Posted by gpw
The T-1 was never designed as a model of efficiency.. just a simple self-righting trainer with an extremely cheap motor ...
Simulations ... seem not to cover ALL the possibilities , but we don't argue about that ...
I expect that the simulation is in fact covering the possibilities just fine: the prop DOES spin pretty darned fast, and at that speed, the pitch-speed of the thing would be pretty high. But in fact it drifts along at a speed not TOO much greater than the speed I can run...so clearly, the prop isn't moving anywhere near pitch speed. (In fact the same motor/prop on Jerbear's Simple Wing moves the plane a GREAT deal faster). So...probably the prop IS running in a stalled configuration...but it's still providing the thrust you need, so you live with it. In the interest of getting a little more "oomph" at takeoff, I shifted to a 4 x 2.5, which seems to work well. But the 3x3 worked decently too. (By the way, most small motorboats -- dinghies, etc. -- operate with their props stalled almost all the time...but it works fine!)

Just to sanity-check: 24000 RPM x 3 inches/rot'n = 72000 inches/min = 6000 ft/min ~= 1 mile/min = 60MPH. Figuring 50% slip (typical for props in the water...dunno much about air props yet!), you'd get 30MPH. If the real speed is more like 10MPH, then we have...oh...80% slip...sounds like stalled operation to me! (24000RPM = 400 turns per sec = about a high "G" pitch for the song it makes, too -- sounds about right for that whine. I'm assuming that each "turn" makes two "pulses" in the air, hence an 800Hz sound...)

--John
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Old Mar 29, 2007, 05:37 PM
gpw
“There’s no place like Foam”
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The T-1 flies so slow , it's able to remain in one spot as the planet rotates at 900mph underneath ...At that speed the prop can't be stalled ...
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Old Mar 29, 2007, 06:10 PM
Tinkerer
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RI
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Quote:
Originally Posted by gpw
The T-1 flies so slow , it's able to remain in one spot as the planet rotates at 900mph underneath ...At that speed the prop can't be stalled ...
Wow! The man not only invents great planes, he also invents amazing excuses!
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