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Nov 26, 2018, 07:07 AM
gpw
gpw
“There’s no place like Foam”
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Thanks VT , I thought it might be informative for new guys …. I liked the part where he slices the foam on a table … My old flying buddy Capn’ Bill used to slice Blucor in half by doing that … and a good method for recycling foam sheets from packing foam …

And he went completely through the build , a good example for new builders !
Latest blog entry: Lost plans
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Nov 30, 2018, 05:04 PM
low tech high tech
vtdiy's Avatar
GPW, your last post has been invisible due to RCG server problems, wondering if I post this it will appear -- or will this one disappear, too....worth a try anyway.

Anyway, might as well make this one useful....so...

In the dive test for CG, I know you've written this a gazillion times before, but can't locate it through RCG search for some reason., anyway in your dive test, does an increasing dive mean the CG is too far forward, (as I think you've written before) or too far aft (as M Drela's glider test sheet seems to say). Or is the difference he's talking about gliders in glide trim, and you are talking about chopping power on a motorized model?

signed.....Confused.
Nov 30, 2018, 05:05 PM
low tech high tech
vtdiy's Avatar
Hey, it worked ... your last post now shows up!

Four days after the fact, but what the heck.....
Dec 01, 2018, 06:53 AM
gpw
gpw
“There’s no place like Foam”
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Thread OP
VT as we can recall, on a powered plane dive test , a too far back CG will make the plane dive more , a nose heavy plane will recover from the glide … Sounds backwards doesn’t it … ? Backwards from the glide test …
Latest blog entry: Lost plans
Dec 01, 2018, 01:59 PM
low tech high tech
vtdiy's Avatar
Thanks GPW, I think I'm getting confused by thrustline, CG, and hstab decalage by the model I'm trying to trim now (the old P-40 -- crashed and sitting for a couple of years, now somewhat rejuvenated.) But This all applies to a trainer one, too, or any powered model.

So, back to the problem -- I have it trimmed now to fly beautifully, power on. Increasing throttle increases climb rate and speed very linearly, and it doesn't balloon at full power. So behavior under power is really nice. But chop the power and it dives.

Now, it already has quite a bit of downthrust and low to full throttle seems nicely flyable. I'm wondering whether it means I need even more downthrust (though would seem excessive), or is this some kind of a CG problem?

I WAS thinking it was nose heavy, but now with what you wrote and the Drela page, that seems to be a negatory. Yet I think I remember somewhere I read the opposite -- that nose heavy on chopping power could put a powered plane into a dive. I was thinking then that there was a difference between the Drela glide test, and a powered plane chop power test:

He was saying put a glider in good trim and level flight, then bump the elevator down momentarily, and watch the dive -- does it increase, stay the same or decrease.

That seems different than a powered plane, where chopping throttle and finding the glide itself is steep. Normally I'd think "needs downthrust" then. But I'm still just wondering if this could mean it's nose-heavy?
Last edited by vtdiy; Dec 01, 2018 at 02:06 PM.
Dec 01, 2018, 02:15 PM
low tech high tech
vtdiy's Avatar
Thinking about it more, must be thrustline. Can't be anything else.
Dec 01, 2018, 06:30 PM
gpw
gpw
“There’s no place like Foam”
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Thread OP
I think the thing to do is adjust the Glide first … then adjust the power .. The transition from power on to power off should be Smooth …going from power into glide mode without balooning or diving ( thrust adjustments ) …. Cutting the power naturally will cause the plane to sink without affecting “trim” ( attitude ) . Just gradually sinking in a level manner is preferred …
The CG should be ~ 33% to start ...
Latest blog entry: Lost plans
Jul 10, 2019, 07:22 AM
KZ RIDER
raythomas's Avatar

Hate to ask----But it's been a while


And I drug out one of my old T1 builds from years ago. Still flies good, it's just that the old 280 has finally given up the ghost so to speak.
Was researching this thread to try and get an idea of what would be a good brushless replacement motor. I got all the way to page 22 and thought, dang this is gonna take forever to read all the way up to over 200
So can somebody suggest a modern day suitable replacement brushless motor for me?
I'm sure HK has something that would work good.
And while your at it, maybe suggest a few Lipo pack choices as well

Thanks Fellows.
P.S. Still a great flying little plane even after all these (14 ) years !!
Jul 10, 2019, 10:45 AM
Too old to rock-n-roll...
TooJung2Die's Avatar
I powered my T1's with a 1510-2200kv brushless and a 5x3 prop. That was enough motor for both a 30" and a 40" wingspan T1. I've tried to buy another recently and found them on Aliexpress. You can use just about what ever you have on hand to power a T1. I even used the electronics from a Harbor Freight Yellow Bee airplane. I used 2S batteries. 850-450 mAh are about the right size, positioned for CG.
Last edited by TooJung2Die; Jul 10, 2019 at 11:58 AM.
Jul 11, 2019, 05:15 AM
gpw
gpw
“There’s no place like Foam”
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Thread OP
The real trick is to not Overpower it … It just needs enough power to fly ( training speed ) . Later as you gain confidence there are other foamies better suited to learning aerobatics …Trainer One is just a Beginner’s plane , something the wife and kiddies can steer around at the park … with no broken noses or props !!!

I also like the EZ-Fly trainer ( motorhead ) which does essentially the same thing …

Many are called Trainers , but Aren’t really … We basically need a plane that essentially flies itself …
Latest blog entry: Lost plans
Jul 11, 2019, 09:52 AM
KZ RIDER
raythomas's Avatar
Quote:
Originally Posted by gpw
The real trick is to not Overpower it … It just needs enough power to fly ( training speed ) . Later as you gain confidence there are other foamies better suited to learning aerobatics …Trainer One is just a Beginner’s plane , something the wife and kiddies can steer around at the park … with no broken noses or props !!!

I also like the EZ-Fly trainer ( motorhead ) which does essentially the same thing …

Many are called Trainers , but Aren’t really … We basically need a plane that essentially flies itself …
Yes sir, I've know what your talking about.
I have read where you have stressed this over and over to others.
My thing is, brushless motors have come quit a long way and so have Lipo's.
So what I want is not "POWER" so to speak.
What I want is a nice brushless motor that is around a 250 - 280ish brushed motor in power output.
The plus side of wanting this is the lighter an aircraft can be made compared to the old heavy "CAN" motors.
A lighter motor along with a lighter flight battery would in my opinion be a win-win situation.
Cause we all know, lighter means S-L-O-W-E-R

Thanks
Ray
Jul 11, 2019, 12:19 PM
gpw
gpw
“There’s no place like Foam”
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Thread OP
Ray , if I built one today ,. I’d use a “Blue Wonder” motor… I don’t know what it's called now , but it’s strong and Light and is plenty of power with just 2 cells on a small prop …
Any of you guys up on the latest info for those …???

I still have a couple new J250’s that would still work with an older brushed controller ( of which we still have a few hanging around …) NOISY but still plenty of power …and not too fast .


And if you’re going for Really LIGHT , and Very SLOW try a LARGE low pitch prop spinning at low rpms … We ran the J250 motor on a GWS gearbox turning a 12X 4 prop … whch acted like a governor on the plane keeping the speed very low but with plenty of thrust to stay aloft … Needless to say that won’t work on a Trainer One or EZFly , but it will work on the Trainer Two … the next step …
Last edited by gpw; Jul 11, 2019 at 12:26 PM.
Jul 15, 2019, 01:44 PM
Bit-Twiddler and Flyer
I've used this "Blue Wonder" motor from Heads Up RC and it works quite well.

HURC-300-Blue-Wonder-1300kv-Outrunner-Brushless-Motor
Jul 16, 2019, 06:12 AM
gpw
gpw
“There’s no place like Foam”
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Thread OP
GG, that motor ^ turned out to be the most versatile motor we used ….
Latest blog entry: Lost plans
Jul 16, 2019, 10:40 AM
KZ RIDER
raythomas's Avatar

Anybody got any ideas on


maybe extending the nose section or building a little cockpit area to hold a small lipo battery pack?
Seems like I could use the weight a little more forward to get the CG just right.
I mean I could just tape or velcro the battery on but that would look stupid.
Was wanting something that looked more like a cockpit, or at least looks good
Cause we all know, when it comes to flying "style" is everything !

Thanks
Ray


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