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Old Apr 07, 2007, 09:07 AM
Good glue is evil
melbourne australia
Joined Sep 2003
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those rubber prop adaptors are great for putting 4025's on to a 2mm shaft
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Old Apr 07, 2007, 02:08 PM
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vtdiy's Avatar
Southern Vermont
Joined Feb 2007
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I think I had my first flight!

At least I didn't crash and flared out for a nice landing, after cutting the throttle. Problem is, I'd only flown for 20 seconds doing a single circuit, and I didn't want to land. But I was getting into trouble near trees, so cut throttle and centered everything. Saw it was coming down fast kept it straight where I wanted it. And flared for a nice touchdown.

This was after a bunch of glide tests -- each resulting in a little damage and repairs. Then two powered crashes. One low in a tree.

A lot of a beginner's problems in building their own trainer occur while trying to trim out a plane at the same time you're learning to fly. We don't have a feel for corrections in flight yet, and we don't know for sure if glide tests are right. What it should look like.

Standing on a 2 foot rise, I got about a 30 foot glide after a light-medium throw with the battery in a position to give a CG of about 30%. But I don't know how this plane is supposed to glide -- is that right -- or should it have been 40 feet, or 50 feet -- or 60?

I think it may have been too short, now after the other flights. Under power she did not want to climb, though I felt it had plenty of thrust. Pulling back on the stick increased the angle of attack, but she seemed to wallow without climbing very much. Letting off on the stick, she'd enter a slight dive.

After I killed power, she dove slightly -- what I thought was the normal glide. But when I pulled back on the stick she suddenly found her lift and barely sank at all. Loooong glide I think that's much more like the normal glide should be. Is that what you experience?

So, I'm thinking -- correct me if I'm wrong -- I should move the CG back a bit? I don't know about changing the motor thrust angle yet -- that might be needed too. I don't want to move the CG too far aft.

I'm thinking the sttepness of the glide was responsible for the damage to the plane in the glide tests. If you are hands off in a glide test, should it land without damage, or do you have to flare it to land well. Mine has no landing gear, and I'm landing on snow, which really grabs the plane right now -- lawn dart style -- in a hands off glide.

Anyway -- looks like ther is light at the end of the tunnel. Wind has picked up today so can't fly again -- but maybe this evening or tomorrow morning early.

Thanks GPW!
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Old Apr 07, 2007, 02:14 PM
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Southern Vermont
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I guess the question is:

What am I seeing as a problem?

Is it thrust angle, or CG location, or a need for increased incidence (horizontal stab trim)?
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Old Apr 07, 2007, 02:58 PM
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Lake In The Hills, Il
Joined Jun 2005
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Quote:
Originally Posted by vtdiy
After I killed power, she dove slightly -- what I thought was the normal glide. But when I pulled back on the stick she suddenly found her lift and barely sank at all. Loooong glide I think that's much more like the normal glide should be. Is that what you experience?
vtdiy,
start by triming the elevator to get that long glide hands free. Than worry about the rest later. Sounds like you have your CG close.
windy city
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Old Apr 07, 2007, 04:44 PM
gpw
“There’s no place like Foam”
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United States, LA, New Orleans
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You're doing well ... it really isn't a glider , but a slow , easy flying trainer...I'd move the cg to 33% and see if that helps ...
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Old Apr 07, 2007, 09:20 PM
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Southern Vermont
Joined Feb 2007
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Thanks GPW and windy city.

Had 4 very short flights this evening, but flared and landed all of them. One or two circuits each and a few glide tests. Moving the CG aft wasn't the answer -- transitioned to scalloping stalls after shutting the throttle -- was able to correct with elevator and land.

I moved the battery fwd again, then tried up trim. That worked a lot better -- but needed almost full up trim to give a gentle climb -- about 1/8" of elevator travel. Had trim problems with rudder too, and inadvertently gave it full rudder trim to left. Plane then climbed in a tight spiral -- which was nice considering the restricted field I'm flying from -- about 150 feet to tall treelines either side it easily fit in a third of that, going up. I straightened it out, but suddenly found I had to pilot! What a surprise. Heading for the trees. Probably should have left it in the climbing turn until I got altitude.

But it was just as well, as the wind came up from calm all of a sudden, and I fought to put it down on the ground. Pulled it off, and grabbed the plane to walk back to the house. The wind was blowing, so no more flying -- just when I was almost there.

Well tomorrow is another day!

Got some damage just from repeated landings in the snow. There's a crust on the surface, and the nose digs in unless really perfrect flare. Digs in like a knife blade until the snow crust hits the battery with a pretty good impact. This tends to run a horizontal split under the battery, and peel the velcro off the foam.

For this kind of flying it would be better if the nose was rounded on the bottom and there was some width instead of a knife blade. That would tend to ride up on the snow. Or maybe a sort of a single ski forward.

I guess I could glue half thick inch cheeks of EPS either side of the fuselage below the battery, with a rounded nose, and tape the bottom. That might support the battery, too. I don't have a flat pack, mine is a double row of 3 1/2 AA cells, and it tends to hang a little off the velcro, being thick and heavy.

But progress. GPW your design is doing what others haven't been able to. Land with me at the controls!

Forty years after buying a Junior Falcon, and a tube of Ambroid......
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Old Apr 08, 2007, 07:54 AM
gpw
“There’s no place like Foam”
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Vtd , sounds like you're doing Great !!!
here's the method we use to trim them out ... once you get the plane to a safe altitude, fly straight and level , chop the power ...if it just goes on straight , the cg is OK , if it dives , it's nose heavy, if it goes into "scalloping stalls" it's tailheavy ... That's for the glide...
Once you get it gliding properly and straight and level , power off , then quickly add power..again it should move straight ahead ... if it dives then you need some Up thrust (on the T-1 the rear of the motor pointing UP, if it climbs alot , the motor needs some downthrust ..T-1 motor rear pointing down .... also , if adding power tends to make it turn ...like to the left with the motor torque((typical), you need some right sidethrust (T-1 motor rear pointing towards the right as viewed from the top).. Hope that helps???.... once you get it trimmed out , anything you do should go straight forward or climb slightly !!!
PS wait for the calm weather ...
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Old Apr 08, 2007, 09:06 AM
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Southern Vermont
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Thanks GPW that sounds like perfect advice -- I will definitely do that once I get enough altitude.

Flew six times this morning and never made it above about 30' feet. Flying between two rows of trees -- but never hit a tree and landed well every time. Probably did 3 or 4 circuits max -- don't know -- was too excited to count!

Seemed calm when I started, but natch a wind gust hit a hundred feet out from the hand launch. I was able to hang in there, though, just avoiding obstacles and saving stalls. Ability to self right in this plane is great, as is the gentle stall -- I think it recovers in about 15 feet on its own.

Near ground level the wind dies, I think the trees help with this. Probably I wasn't able to do much above 30 feet because wind there, while not apparent on the ground. I think it was probably turning into the wind when it got to the "wind altitude" and then stalling and falling back. I'd recover it turn to miss the trees, level the wings and chop power. It was easy to flare in then, below the wind.

Six flights -- used up the battery capacity in this cold (20 F -- they don't last as long) no crashes. No damage. Just need a charge.

Actually, I'm charged!

I'll wait for a calm, as I really do want to do the trim routine. Right now I have 90% left (not right) rudder trim and 85% up trim to give a straight easy climb. Drop that to 75% up and I believe she's straight and level. But can't judge the glide due to lack of altitude and wind, so no telling what those full power trims actually mean. We'll just have to wait and do it the right way.

This is Great!
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Old Apr 08, 2007, 09:32 AM
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Southern Vermont
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Thinking ahead, GPW to your Gee Bee.
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Old Apr 08, 2007, 11:38 AM
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RI
Joined May 2005
184 Posts
Quote:
Originally Posted by vtdiy
Thanks GPW that sounds like perfect advice -- I will definitely do that once I get enough altitude.

Flew six times this morning and never made it above about 30' feet. Flying between two rows of trees -- but never hit a tree and landed well every time. Probably did 3 or 4 circuits max -- don't know -- was too excited to count!

Seemed calm when I started, but natch a wind gust hit a hundred feet out from the hand launch. I was able to hang in there, though, just avoiding obstacles and saving stalls. Ability to self right in this plane is great, as is the gentle stall -- I think it recovers in about 15 feet on its own.

Near ground level the wind dies, I think the trees help with this. Probably I wasn't able to do much above 30 feet because wind there, while not apparent on the ground. I think it was probably turning into the wind when it got to the "wind altitude" and then stalling and falling back. I'd recover it turn to miss the trees, level the wings and chop power. It was easy to flare in then, below the wind.

Six flights -- used up the battery capacity in this cold (20 F -- they don't last as long) no crashes. No damage. Just need a charge.

Actually, I'm charged!

I'll wait for a calm, as I really do want to do the trim routine. Right now I have 90% left (not right) rudder trim and 85% up trim to give a straight easy climb. Drop that to 75% up and I believe she's straight and level. But can't judge the glide due to lack of altitude and wind, so no telling what those full power trims actually mean. We'll just have to wait and do it the right way.

This is Great!
Sounds like you're doing wonderfully. In another few days, it'll all seem easy. Once the CG is far enough forward, you've got some room to adjust it -- a bit too far forward doesn't seem to have a big effect. And as gpw said, you can point the front end of the motor down to make the plane go up as you apply power, or point the front up to make the plane go down. You can also adjust the height of the motor, keeping it level: moving it lower will cause you to climb more when power's applied; moving it so that that centerline's above the wing will cause the plane to dive more as power's applied. If you find yourself having to point it up or down a lot, consider raising or lowering it as an alternative.

Something we did for the T-1 when we were flying it on a frozen lake this year, which would probably work on snow, too:

1. Make a 'cover' that's glued to the right-hand side of the nose, bends around the front, and comes back over the left-hand side of the nose, covering the battery and perhaps your ESC too (depending on where you put it). It's held in place by a rubber band around the nose, and tends to protect the battery during those nose-first landings. You can see it here:

http://www.rcgroups.com/forums/attac...mentid=1214613

2. Make a "skid" for the bottom of the nose -- just a bit of bent fanfold that curves up a tiny bit. This is sacrificial -- its gets chewed up/worn away instead of the bottoms of your batteries suffering.

(Ignore the bi--plane aspect of that photo ...that part DIDn't work out so well :-( )

--Spike
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Old Apr 08, 2007, 03:54 PM
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Southern Vermont
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Spike, that should be patented.... would you call it "The Trainer Bra-Ski" ? Or maybe The Braboggan?
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Old Apr 08, 2007, 04:54 PM
gpw
“There’s no place like Foam”
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United States, LA, New Orleans
Joined Jul 2002
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Trainer Spike Bra...
Great idea really !!!... all I need now is some snow ...
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Old Apr 08, 2007, 05:40 PM
treefinder
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SE MI
Joined Oct 2004
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Vt: noticed your comment about nose jobs, (and the interesting and prettier bra pix) and had to chuckle. attached is my "glued up nose" I seem to be tracking pretty close to you. Tried rc several times, with balsa/monokote painstakingly built, crash, disallusion, quit. This plane is the solution to that problem, for sure! After bruising up the nose, I decided to just overkill it. It flies fine and no more damage when I land it in the alfalfa field. It's close cut for winter, so when the plane comes down, it catches on a stem and noses over.
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Old Apr 08, 2007, 06:16 PM
gpw
“There’s no place like Foam”
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Spring , nice nose job/protector .... whatever works is Cool !!!
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Old Apr 08, 2007, 08:35 PM
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Southern Vermont
Joined Feb 2007
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Hey Springer, you've got a real cockpit. Once I do a complete battery discharge in one flight I was thinking of cutting mine out.

Yup same route. I remember when Monokote was invented and when foam core balsa covered wings were new -- tried both and made a brick of a wing with an epoxy fiberglass joiner. I had an OS Max .19 engine I could never start. That was a bitter disappointment as a kid. I just finally quit after three crashed planes. I did have a lot of fun with 1/2A controline planes before that though. It was when I set my sights on RC that I spent years building planes that lasted a minute.

You can see last years alfalfa? It's snowing now!
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