arrio

My Feedback: (17)

I read all the posts about the this gyro and it realy caught my interest. I was going to buy the kit, but a friend talked me into building one from the posted plans. I had the electronics for it already from one of my foamys, so I just needed to get few more things. I decided to build this one with just dowels and spruce instead of the carbon or fiberglass tubes. The weight penelty shouldn't be too bad. I have the airframe now completed and am starting on the blades. The rotor head parts are all here exept for the metal straps. Going to pick those up today. Hopefully, I should have it finished for a flight this weekend.
Pictures to follow soon.

arrio

My Feedback: (17)

Well, Its nearly done. Just need to finish the rudder controls and the motor installation. The blades are ready for covering too. I should be able to test fly this thing today.

mnowell129

Looks good. Let me know how the GWS wheels work out.
I was unhappy with the ground handling till I put the
MPI wheels on.


mickey

P.S. I built up a kit G3PO for the LHS on Friday, used the
Himaxx 2812-850, 3s 1050. It flew right off with no trim changes.
Elevator setting was about -10 degrees with respect to the shaft.
I actually painted this one all yellow. Will try to post a picture
when I go back tuesday to instruct the LHS guys how to fly it.
One employee has already made straight hops with it.

arrio

My Feedback: (17)

Actually, Those wheels are MPI products. I ordered 2.5" MPI Lite wheels online, but they did not have a picture of them. I just asumed that they would be the stronger plastic rims. But these are what I got. I did find some that are correct though. They are on the way.
These Microlite style wheel are not as brittle as the GWS, but still kinda wobbly under presure.

I'm a little confused about the -10deg elevator setting with no trims. Isn't the swash level with no trims?

mnowell129

Level is a difficult word to use here.
You need to measure relative to rotor shaft itself.
When the swashplate is 90 degrees to the rotor shaft,
or parallel to the rotor blades,this is the no trim. (This will
be 22 degrees up from the motor stick and maybe
28 degrees from "level" with the ground. )
10 Degrees of down trim means that the swasplate
is 10 degrees down from there. This will look positive when
the gyro is sitting on the ground, but ignore that. Measure against
the main shaft.
mickey

mnowell129

This is what 10 degrees down is.

mnowell129

Better picture.

arrio

My Feedback: (17)

Ahh, OK. So this is something that you actually use the "trims" (those on the radio face) to set the swash angle for flight. The actual "no trim/center" is still 0deg swash.

Thanks,

mnowell129

Yes, however now that i've built 7 or 8 of these I go ahead and make the
pushrod the right length for the -10 with the trim centered. Sometimes I use
subtrim on the radio as well. I like to look down and see the trims centered as
a mental checklist.
mickey
Just revived the pusher. I'm making some progress on the ground handling.

arrio

My Feedback: (17)

Thanks for the clarification. I'll do the same. I too like trims in the center. Its one of the reasons I bought this nice radio with so many trim features (10X).

Glad to hear you are making progress on the Pusher. Pusher and a Tandem is high on my list of gyro projects.

I would be out runing this gyro around, But I seem to out of props, and I can't find my prop adapter. The only shop in the area thats open on Sunday closes at 5pm, and wouldn't you know it, I look up at the clock and its 4:59[X(] [>:]

arrio

My Feedback: (17)

Some Pics of the model ready fo flight (less prop).

mnowell129

I noticed that you decided to skip the kevlar wrap around the
head and bearings. Watch for slop to develop here because
after it wears some it will come off in flight. You can guess
how I know this.
mickey

arrio

My Feedback: (17)

Yeah, I figured I would get it flying first. If it survives the trail flights, then I'll go back and wrap the head.
I went over my friends place and he had a spare prop and adapter. Actually he made a prop saver for me on his lathe (really nice of him) took about 10 minutes. Finnally was able to taxi it around but couldn't get the head speed up enough. 150-200 foot runs. A few times it looked promising, then it would do a right roll and tip over. Blades were getting dinged up pretty good. Called it quits before I really broke something.
I rechecked the pitch. It has -3deg, read by one of my heli pitch gages. Maybe need some more neg pitch?
The blades also may have been a little too snug. They didn't seem to want staight themself out very well.
If I get time tomorrow evening, I'll try it again

mnowell129

Are you running the aerobalsa blades ? If so the "eye" method is to set the blades
so that the aft portion of the top of the blade is flat. It's about -4 or -5 from my
schluter gauge (that dates me doesn't it) but the real
setting comes from flight test. Too much neg gives moderate rotor speed but
fast flight. Just the right pitch gives the highest rpm. Too much positive makes it
really hard to get into autorotation and the rotor stops easily in flight.
Blades need to be adjusted straight out before taxi and the blade
bolts need to be tight enough that the hand spin doesn't change
the alignment. A little blade misalignment makes it hard to get the autorotation
started.
Hold the gyro in your hand 50-60 degrees nose high and give it a spin.
In a 3-5 mph wind (or if you can run) the rotor should come up to speed (500-600 rpm,
basically scary to hold in your hand) then adjust pitch to make this happen.
This is also a good chance to set the track. Once you do this the blades will
be in the right place and a hand spin shouldn't be able to knock them off alignment.
If so tighten the bolts.
If you can get the flight RPM in your hand you can just drop the nose level, give
3/4 throttle and give it a little shove straight ahead and it will just fly away.
Problem with this and the new model is you don't know where trim is.
Best approach is to make short taxi hops until the RPY (roll,pitch,yaw) trims are
set, then handlaunch is a no brainer.
The rollover on the ground is characteristic of trying to lift off with up elevator
and not enough rpm. I've done this 1000 times during test. It looks like it will
fly but its not ready.
Flight RPM will be obvious as a slight increase in motor
power will cause a liftoff without any elevator control. It will actually come
off the ground as a surprise to you.
My typical takeoff procedure.
1)Straighten blades.
2)Give a good hard flip.
3)Give a quick blip of 3/4 throttle.
4)Back off throttle to 3/8.
5)Wait for rotor speed to come up during the fast taxi.
6)When rotor is up to speed slowly feed in power until it
breaks ground by itself, usually before 3/4 throttle.
7)Throttle back to desired climb.

The hardest part is to wait at step 5. What you are looking for
is the same RPM that you had in your hand held nose high into
the wind.

sounds like you fly heli's so be ready to fly rudder and keep in
coordinated in the turns. The slower it goes the more rudder is needed
to fly much like a heli. Try to avoid down elevator as this just stops the rotor.
Manage your altitude with throttle, but flying heli's you'll know how to do that.
mickey

arrio

My Feedback: (17)

Got in some time this evening at the flying field. Thankfully, we have a nice 400ft asphalt runway. I had to share the runway with a couple other guys, which meant I watched them fly now and then. I finally got it to take off nice and straight. But my battery was down after the numerouse trys and ground runs. And it didn't have enough poop to keep it going on the downwind leg. It settled down in the tall grass. No damage except for a cracked dogbone link at the head. I have a spare. It might also be the prop and gear ratio selection I am running. I have a HiMax 4100 with a D reduction (like GWS) Prop is a 11:4.7. ESC is a CC25 and LiPoly 3S 1300. I have other props to try and other ratios too. The guys at the field really got a kick out of this this. [8D]

mnowell129

The 2015-4100 doesn't have enough power, especially
dragging the weight of the 1300's.
The 2025-4200 will do the job.
These things have a lot of drag.
You need thrust = weight as a bare minimum.
I have good results with 3S1P 1050 batteries
on Himaxx 2812-850 outrunner and the similar axi,
razor 400 6.6:1,
himaxx 2025-4200 6.6:1.

Himaxx 2025-5300 6.6:1 on two cells and a 12x6 APC Slow
is workable.

When you finally get the kinks out you can increase the pitch
and fly on less power but its tough on the inital setup.
You can also fly on less power if you twist the blades (washin,
opposite from fixed pitch heli blades) about -12 root, -2 tip.

glad the guys at the field are enjoying it. Everywhere I fly mine
people seem to be interested. Something totally different.
mickey

arrio

My Feedback: (17)

Thanks for the motor info. Don't have a 4200, but I do have a couple nice outrunners that should do the job. A Himax HC2816-890kv outrunner which by the spec sheet has a +200W Max power. Also have E-flite Park-370 outruner that according to the specs should produce about 120W (VoltsxAmps=Watts)

Whats the technique you use to steam the blades to put in the twist? Hold the blades over a pot of boiling water?

mnowell129

Yep.
I hold two blades together and hold the tips and the roots.
Hold them in steam and twist. Doing them together puts the
same twist in both.
I'm not very exact so I just use the TLAR method. I try to
overtwist a little so when they relax they end up with about
10 degrees of twist.

I'd try the 370 first. 120 watts is plenty.
Don't over pitch the prop, 4.7 is usually enough.
The 12x6 has a lot of torque reaction.
mickey

arrio

My Feedback: (17)

Flew my model this evening. SUCCESS !
It took off in about 75 feet. (very light breeze) Had to correct and trim a little forard. But then it sailed along nicely. The speed was a little faster than I would have thought. But after a short bit it seemed kinda normal moderate speed. As you mentioned rudder is pretty much the main function for directional control. I really need to put some side surface on the model. It is too easy to loose orientation, especially during low light evening hours. (need to get the field a little bit erlier too )A shame to have to do this because the no frills airframe really appeals to me. I say this, because once again, like yesterday I was in a left hand turn to come back the other way and its like half the gyro dissapeared. Perhaps I had too much roll input and when it banked, there was nothing but stick from front to back. So, anyway it dove into the grass again. Broke it up a little bit, but easily repaired as none of the important stuff was hurt.
The E-flite Park370 did the trick for power. I tried a couple different props, checking static thrust and operating temps. The APC SF10x4.7 seemed to be the about best. My Wattmeter showed about 100 watts with that combo at full gas. 120 watts for this motor I think is a little too optomistic. Looks closer 100W.

mnowell129

Congratulations!
Bright colors really help. I make mine yellow.
If you want a little orientation try putting a
pilot figure up front with a bright colored jumpsuit
and contrasting helmet. I use 6mm depron and markers.

100 watts is about what I'm running in all mine for
good performance, so this makes sense.

Now that you have it trimmed, try reducing the negative pitch
in the main rotor slightly. Your lowest flight speed will occur
at the highest (least negative) pitch where it will maintain
autorotation. Twisted blades will help the low speed too.

Congrats again.
Now where's the in flight picture?
mickey