700 Bell 47G from Vario

[Nade]

Finally, finally got this beast programmed and took a chance on its first maiden test flight. It was a bit tail heavy and had a strong torque yaw to the right. Will attempt to make some gyro adjustments and give it another test. But I think once it is all dialed in, it's going to be a really nice bird to fly! Here are parts 1 and 2 of the maiden flight.


Vario's Bell 47GII maiden test flight part 1. - YouTube

Vario's Bell 47GII maiden test flight part 2. - YouTube

 

[D.O.G.]

Finally, finally got this beast programmed and took a chance on its first maiden test flight. It was a bit tail heavy and had a strong torque yaw to the right. Will attempt to make some gyro adjustments and give it another test. But I think once it is all dialed in, it's going to be a really nice bird to fly! Here are parts 1 and 2 of the maiden flight.


Vario's Bell 47GII maiden test flight part 1. - YouTube

Vario's Bell 47GII maiden test flight part 2. - YouTube

Once you get the fine tune adjusting done, that bird is simply going to be awesome. Thanks for sharing.

 

[Nade]

Thanks very much D.O.G.! In all honesty I really do think when it is all set up, that out of all the birds I have, it's going to be the best and most enjoyable to fly!

 

[Admiral]

Looks awesome in flight, well done.

 

[Nade]

Looks awesome in flight, well done.

Thanks much too Keith! Appreciate it!

 

[Tony]

Hey Rich, fantastic job on the maiden!

A couple things I noticed. I think you are right, I think it's slightly tail heavy, but you also didn't have the canopy on the front of it which will add a little weight. If you put the blades perpendicular to the tail boom and pick it up by the bottom of the blade grip screws, it will tell you if it's tail or nose heavy. Just add weight where needed and you should take care of that issue. That is unless it was a drift and the gyro thought the tail low was level position.

Another thing I noticed is your nose right yaw. This was caused by your motor fluctuating. I'm guessing you are running a linear throttle curve and this is bad for Rate mode helicopters (I am pretty sure you are running in Rate anyway by the way the tail looked, and very low rate if any at that. My suggestion to you is, when you were up in a nice hover, remember the stick position (ie 65%) and set a flat throttle curve at 75%. You take your stick and ad 10% and set it as a flat curve. I highly doubt you are going to do flips and rolls with this, so running a throttle curve of 0 75 75 75 75 is perfectly fine. I heard a very slow startup in your ESC, so that big of a jump is not going to hurt a thing. But I HIGHLY suggest a flat curve. It will all but eliminate your tail yaw issue.

And is that tail blade supposed to stop before the main rotor? Not sure I like that. If you burn up an ESC or or your motor dies or you strip the gear in flight, your orientation training has to be spot on because there is no controlling that tail once you lose the motor. If this is the way it's supposed to be, great. Otherwise I would look in to this.

But again, fantastic maiden!

 

[Nade]

Thanks much Tony! Yes, I need to get the rest of the "canopy" installed. I found when I had the interior and outer globe in place, it still was just a slight bit on the tail heavy side. So I'm going to pick up a package of RC lead bars and place them in the front of the "hull". And since the floor will go over them, they'll be hidden. That should bring it very close to the COG.

You are correct on the throttle set up. I will be setting it up to governor mode but just wanted to give it its maiden flight to see if I could get it to a hover without installing the remaining canopy parts. I don't want to "permanently" install those parts so I'll have access to the FBL controller in case I need to make any changes. There is an led on the controller that utilizes different colors for different modes. Once I confirm those other relevant modes are available/active, then I'll install the rest of the heli and dial it in.

And I was impressed with your last observation Tony! I hadn't thought of it but you're right. It unfortunately is in the design. Because of how the "tranny" is designed, the tail blade stops with the motor, where the main blades shaft with its one way bearing disconnects, if you will, once the power is shut down. That allows the main blades to spin to a stop.
The motor is connected to a belt on the bottom of the housing that transfers power to a "long" verticle shaft that the tail blade drive shaft is geared to. The power continues through that verticle shaft to gearing that engages the main blades one way bearing shaft. So once the power is shut down the tail blades stop rotation with the motor whereas the main blades continue to spin because of the shaft's one way bearing. (See pictures)

Yeah, I agree Tony. I'm pretty much dead in the water if I suddenly loose power. There's no one way bearing on the tail blades. And I've checked the load on the gearing from the motor to the main blades shaft. Everything spins freely. No binding or labored turning of shafts, gears or belt. The motor just happens to stop rotation quicker than the main blades. No auto-rotation landing going to happen here. Oh well.

The Goblin's design allows for auto-rotation because the tail blades are directly connected to the main blades by the drive belt. So with the oneway shaft bearing both blades can continue to spin, disconnected so to speak, from the motor should any of the electronics fail.

But in reality, although I've practiced a lot with auto-rotation landings on the sim, unless I'm real high in altitude when something fails I probably won't be able to respond quick enough to utilize it.

Thanks for your perspective!

 

[Tony]

The thing that matters is you are aware of everything I posted and already had plans for it. So I can keep my mouth shut now hahahahaha. Using a governor is going to be awesome on this bird. Man, I can't wait for the first stable flight with everything turned on and actually ON the helicopter.

Have you thought about running in Heading Hold mode, or are you going to run this one Rate only?

 

[Nade]

The thing that matters is you are aware of everything I posted and already had plans for it. So I can keep my mouth shut now hahahahaha. Using a governor is going to be awesome on this bird. Man, I can't wait for the first stable flight with everything turned on and actually ON the helicopter.

Have you thought about running in Heading Hold mode, or are you going to run this one Rate only?

Not to worry Tony! I never take offense to something that someone offers me for info or questions. I don't care how long a note may be. I find there is always something, some info within that I hadn't thought of, or simply a different perspective. We are always learning, specially me, so I never take what someone has to offer for granted!

To answer you question, I plan on flying on heading hold mode. I have yet to warm up to rate mode but maybe this bird will teach me something. The gyro was set at heading hold mode at 55%. However, the Demon also has a head gyro which aids in heading lock so there's a learning curve there too.

Once I do get this bird fine tuned I can come back with the settings for your viewing enjoyment. )

Thanks again Tony!

 

[Nade]

Sorry everyone. I edited the videos I had links to here. There were parts 1 & 2 and I made one video with them. I've included the link here.

May 30, 2016 - YouTube

- - - Updated - - -

Since I erred by editing the original maiden flight video I posted the complete maiden flight above. It was obvious the heli needed RX adjustments so after making a few changes I did another test flight. I've included that link here. Some throttle and gyro setting changes improved the handling emensely. Still needs some "final" adjustments before complete assembly is done.

Bell 47 Second Test Flight - YouTube

- - - Updated - - -

The nose was showing some left yaw but a major overall improvement.

 

[D.O.G.]

Man, that bird is awesome! Once you learn to fly inverted, you can cut some serious grass . That is one sweet sounding and looking heli. Good luck on your future flights. I Enjoyed your video.

 

[Nade]

Man, that bird is awesome! Once you learn to fly inverted, you can cut some serious grass . That is one sweet sounding and looking heli. Good luck on your future flights. I Enjoyed your video.

Thanks much D.O.G.! Glad you enjoyed the video. Unfortunately this heli is not a 3D bird. I'll only be doing some sport flying with this one. But that's ok. I've got other helis I can fly more aggressively.

 

[Nade]

Well, finally, I reached a "successful" test flight where now I just need to do some fine tuning. The three issues from its maiden flight needing to be addressed were torque yaw, COG, then after changing over to governor mode from fix end points I experienced motor RPM drop in mid flight.

I think we know the torque yaw can originate from gyro settings, COG is a no brainer but I was concerned that the motor dropping in its RPM's was either from being sold the wrong motor or the total gear ratio was wrong. The good news is it turned out to be the battery's C rating was too low. I borrowed the batteries from my Goblin 770, 6s c35 6000mAh and was evident from the second test flight (above) could not deliver the power needs under what I considered a mild load.

After checking the ESC's data log it was evident there was enough ripple to cause the ESC to begin protecting itself and limiting the power drawn. I then tested it with the batteries from my Goblin 630, 6s c45 3700mAh and within seconds it was obvious the problem was in the batteries. Although the new data log still showed some ripple the proof was in the flight.

I had to crop the pics considerably to get them to upload and lost the lower data info. The upper green line in the graph is the current being drawn, the black line in the middle is the throttle in and the lower purple line is the ripple created by the ESC to protect itself. In the "2nd completed 47 test run graph it shows a small but definite improvement in the ripple, but the proof is in the comparison between the second and third videos. Here is the link to the 3rd test video

Bell 47G Successful & Final Test Flight - YouTube

- - - Updated - - -

Incidentally, I was still getting some bobbing and the collective was very touchy , hence bumping the ground, but these can be fine tuned.

 

[Tony]

I have just made a change to the server so you should be able to upload a larger file now. Sorry it took me so long to get to it but it's done now. Try uploading the unedited graphs now and let me know the result.

 

[Nade]

Well, finally, I reached a "successful" test flight where now I just need to do some fine tuning. The three issues from its maiden flight needing to be addressed were torque yaw, COG, then after changing over to governor mode from fix end points I experienced motor RPM drop in mid flight.

I think we know the torque yaw can originate from gyro settings, COG is a no brainer but I was concerned that the motor dropping in its RPM's was either from being sold the wrong motor or the total gear ratio was wrong. The good news is it turned out to be the battery's C rating was too low. I borrowed the batteries from my Goblin 770, 6s c35 6000mAh and was evident from the second test flight (above) could not deliver the power needs under what I considered a mild load.

After checking the ESC's data log it was evident there was enough ripple to cause the ESC to begin protecting itself and limiting the power drawn. I then tested it with the batteries from my Goblin 630, 6s c45 3700mAh and within seconds it was obvious the problem was in the batteries. Although the new data log still showed some ripple the proof was in the flight.



I had to crop the pics considerably to get them to upload and lost the lower data info. The upper green line in the graph is the current being drawn, the black line in the middle is the throttle in and the lower purple line is the ripple created by the ESC to protect itself. In the "2nd completed 47 test run graph it shows a small but definite improvement in the ripple, but the proof is in the comparison between the second and third videos. Here is the link to the 3rd test video

Bell 47G Successful & Final Test Flight - YouTube

- - - Updated - - -



Incidentally, I was still getting some bobbing and the collective was very touchy , hence bumping the ground, but these can be fine tuned.

Ok Tony, here are the two unedited pics. They went through without a hitch. Thanks so much!

 

[Tony]

Fantastic, glad I could get that issue solved. One down, a million to go lmao.