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PTGyro Conversion

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Old 04-09-2007, 07:27 PM
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floridagyro
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Default PTGyro Conversion

Hi,

I have had 2 PTGyros and been flying them since they were available. I just converted one of them to a swashplate control head with a pre-rotator, a design similar to the Begi rotor head designed by Mickey.

Some interesting results. First it flies and handles very well. Considerably better than with the flapping blade head. I have flown it with 2" wide 14" long carbon fiber blades and 1.5" wide 16" long wood blades, both SG6042 profile. The 2" wide blades produce a lot more lift.

When flown with the original design, 3 blades flapping head, I was using an AXI 2808/24 motor which weights 76 grams and a lot more thrust. With the swashplate I am using a Welgard C2830-12 motor that is much smaller and weights 59 grams.

The flapping head had 3 blades 2" wide and 16" long and I'm getting better performance and better handling with only two 14" long blades and smaller motor with the swashplate. Interesting!!

Phil







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Old 04-09-2007, 08:30 PM
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Default RE: PTGyro Conversion

Very interesting Phil. Great stuff!.
I think the key is the blades being held rigidly in the holders.
Another effect may be the flapping head putting a lot of drag
on the bearings.
How about some video?
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Old 04-09-2007, 10:15 PM
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Default RE: PTGyro Conversion

Hi Mickey,

I've wanted to try the conversion for some time, but I wasn't sure if the E-Sky head would handle the weight of the PT Gyro. Interesting, the head with the swashplate and pre-rotator weights much less than the originaly pylon and the smaller motor and one less rotor blade gets the PT weight to about the same as Begi.

I'm also sure that this small motor would not fly the PT as originally designed.

The response to the controls is very crisp as compared to flapping blades. It's like going from a Senior Kadet to a pylon racer.

I suspect it would roll and loop pretty good but I think I'll wait until I get a few more flights.

I'll try and get some video. Today was not good as I was actually flying in the rain.

Phil
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Old 04-10-2007, 08:11 AM
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Default RE: PTGyro Conversion

Phil,
Very interesting stuff.
Looking forward to video.
Quite interesting about the whole weight deal.
mickey
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Old 04-10-2007, 08:26 AM
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Default RE: PTGyro Conversion

I wonder what would happen if you cut the stab off?
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Old 04-10-2007, 09:03 AM
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Default RE: PTGyro Conversion

Hi Mickey,

I guess only one way to find out. One thing for sure, it would be that much less weight. Maybe I'll start with half a stab!!
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Old 04-10-2007, 09:16 AM
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Default RE: PTGyro Conversion

Yes, I was thinking you might trim it down slowly to see what happens.
Clearly BEGi and G3PO fly just fine without. No reason to think
that PT won't either.
Goes with what i've said before, if the rotor is stable, you don't
need a stab to calm it down.
I know that some people don't like the swashplate and flybar,
but evidently you can't argue with the performance.....
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Old 04-10-2007, 11:30 AM
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Default RE: PTGyro Conversion

Hi,

I didn't realize that the response was so slow in our flapping blade design until I flew the swashplate control. Once you get into the delta head with all the parts, I'm not sure there is that much difference in total parts count and or much difference in cost. For sure much less weight, due to the feather servos and mounting brackets.

I'll probably regret saying this, but I haven't had a crash since using the pre-rotator. It really improved the odds of getting the gyro in the air. Most of my crashes were on take off due to a cross wind or slow rotor speed. Also, I seem to have lots of tip overs on landing, for one reason or another. Ground handling is much improved in windy conditions with the swashplate and I've flown in very windy conditions and I taxi on and off the runway and haven't had a tip over yet.[&o] I really hated to say that!! Yes, and I do have a wider running gear.

Mickey, what is the motor down thrust and rotor mast tilt back in the G3PO?

Phil


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Old 04-10-2007, 12:29 PM
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Default RE: PTGyro Conversion


ORIGINAL: floridagyro
Once you get into the delta head with all the parts, I'm not sure there is that much difference in total parts count and or much difference in cost. For sure much less weight, due to the feather servos and mounting brackets.
or assembly time. There is $20 in servo savings alone. I think it comes down to whether or
not you want to DIY your rotor head or not.
It's pretty clear that some builders take great pride in
making as much of the aircraft themselves. Ok for them, but
sometimes advancement in the state of the art comes from
some new enabling technology. I could have done a swashplate
gyrocopter from heli parts a long time ago, it was the availability
of inexpensive molded rotor head parts on the Feda/Hummingbird/Dragonfly
that made making this kind of design economically possible.
I thought that after I had G3PO sorted out that I would go back and make
a tilting head design, but I lost interest. The three bladed tilting head design
is pretty mature, basically unchanged in design since Emilio's ECDC. I can't see
some radical new tilting head design coming down the line, just refinements of
the current design. So I'll stick to swashplates, until I can do an electronic cyclic
control with servo flaps or something. The electronics are there to do this, just need
some tiny actuators....
ORIGINAL: floridagyro
Mickey, what is the motor down thrust and rotor mast tilt back in the G3PO?
The mast is set at 110° from horizontal (20° from vertical). Downthrust is 0 or 5° depending on the builders choice.
The 5° helps it stay level under power changes.
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Old 04-11-2007, 05:44 PM
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Default RE: PTGyro Conversion

Hi,

Tried something interesting today with the PTGyro. I wanted to determine what the minimum mast angle and motor down thrust would be and still sustain flight using the swashplate control. I ended up with 4 degrees on the mast and about 4 degrees on the motor. Now that was one fast gyro but nothing that I would recommend, but interesting[8D]. For the PTGyro about 8 degrees on the mast and 5 degrees motor down thrust seems about right.

Phil
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