gaui 200 md500 help..5 blade suggestions

[domcars0]

Nice idea! I follow your posts.

[alphonso]

Originally Posted by Tilting At Windmills

I too fell in love with the look of the MD500 but was also been grounded quickly by the fragile tail belts. Currently I’m in the middle of testing a possible solution by eliminating the dual belts and going with a direct-drive raised tail using the stock Hurricane 200 tail belt. Surprisingly with some careful removal of material there is just enough room to fit the center tail gear in the upper frame (at servo level) for a straight line to the raised tail. A custom tail-belt guide-wheel mount and a 3-cell power upgrade completes the primary modifications.

Here is a photo of the middle-mount modification for the tail-belt guide wheels – I was experimenting with wheel placement which is why there are 4 holes drilled in the brass plate.


Here is the current flight platform with the 2 blade head:

-link to a larger version of the photo above: https://farm8.staticflickr.com/7102/...0d708af1_o.jpg - viewing at 100% you can see the 2 red tail drive gears tucked in below the upper main-shaft mount.

This week I’m tuning the flight characteristics before risking the MD500 body but have put 5 packs through the bird without issue. Provided I can get a dozen more packs through the airframe in the next week or so, the upgrade path is to add the 5-blade head, get that tuned, then put the scale body back on.

I’ll let you all know how it goes.

Nice work, but could you tell me if you are using the 200 boom or the one that comes with the MD500. The reason i ask is I thought the MD500 one was slightly longer as when i test flew mine without the scale fuse the carbon tail rod was too short. If that's not the case then fantastic and i shall do the same.

if you go the 5 blade route with your build you will need to find a way to get more thrust from the tail as the lower RPM and increased torque from the extra blades is too much for the stock tail, even with the 42mm tail blades. I tried a 15 tooth pinion on the tail and it still wasn't enough and needed to up the tail speed by using 18 teeth on the integrated middle mount pulley (stock is 16). by going direct you wont have that option so perhaps using the X2's 45mm blades will work. There is also the option of using HSC's CNC primary pulley which is a few teeth larger I believe.

Thanks for posting as it's prompted me to start work on the 500 again.

if you go 3 cell you will need to swap to a lower KV motor as even with the 10 tooth pinion the rpm is way too high.

My setup with 5 blades is as follows

Stock 5600 KV or scorpion 2206 5300KV
10 tooth motor pinion
18 tooth middle mount pulley
15 tooth tail pulley
42 mm tail blades
2 cell Hyperion 900 and 1100 mah packs
flat 55% throttle
-3 to +9.5 pitch range

duration about 6 mins on the 1100's

I'm excited to try your idea.

Kind regards, allan.

[Tilting At Windmills]

I’ve continued to refine my MD500 5-blade build and was successful in getting some flight-time in this weekend with the bird largely completed.
This is a pretty long post as I had to make significant modifications to the stock set-up as detailed below – for those of you who don’t want to read down, here is a link to the flight video.
https://www.flickr.com/photos/flickr...n/photostream/


If you have been following this thread you'll know that I've been experimenting with a direct-drive raised tail configuration to eliminate the dependency on the fragile and unavailable stock MD-500 dual-belt set-up. While the concept has now proven to be successful, moving down this path caused me to make numerous changes to the stock set-up as detailed below. Working on with the scale body only compounds the complexity since you have to remove the tail and the body each time you need to change anything because access is so limited with the scale body in place. Here are the main changes I made in pursuit of a solution that would allow the MD500 to fly cleanly with enough power to drive the 5-blade head.
- 3-cell power upgrade: motor & ESC from Gaui X2 including custom lower-frame horizontal members – the X2 motor is taller than the hurricane 200 so I had to drop the bottom plate a few millimeters to accommodate the larger motor.
- Bobby Watt’s upgrade tail housing with carbon tail push-rod for better tail authority– I built a custom brass servo mount to securely attach the servo to the single post of the MD500 middle mount while also building a custom servo arm to align the servo linkage perfectly in-line with the tail boom (required for the linkage to work with the MD500 body). I also had to increase hole in the MD500 body to accommodate the carbon tail push-rod.
- Raised central tail gear to line-up with the raised MD500 tail using the stock hurricane 200 tail boom & tail belt – the hurricane frame upper pieces were trimmed to fit the center gear along with the fiberglass MD500 body be shortened a few millimeters in the tail to fit the bobby watts tail unit.
https://www.flickr.com/photos/flickravatar/14237707733

- Custom tail-belt guide-pulley mounting block – originally I had tried mounting the guide pulleys on a lower mounting plate but was having issues with the tail-belt “diving” below the pulleys and rubbing on the pulley mounting bolt. Now, I’ve taken a stock hurricane 200 middle mount (with the stock guide-belt pulley-wheel mounts) and trimmed it to fit on the tail boom allowing me to maintain the stock pulley location. Also visible in the photos is a small carbon-fiber reinforcement to the upper frame just in-front of the belt guide-pulleys.
https://www.flickr.com/photos/flickravatar/14237709153Z

- Blade 200sr (I think) landing gear - direct mounted to the MD500 body.
- 5-blade head with custom painted carbon blades.
- Gaui X2 tail blades

This weekend I finally was able to get everything assembled and put a few 1100MAH packs through the bird with 5:30 min flight-times and plenty of control at the end of the pack. I’m getting some rubbing between the tail servo-arm and the inside of the MD500 body – there really isn’t very much clearance between the serve and the body with the tail-push-rod parallel to the tail boom but I think I can solve this with a “V” shaped servo-arm. I’m pretty sure this is what is causing the tail wag in the video but won’t know until I attempt a solution. Also I realized that I don’t have any 89mm main shafts so presently the 5-blade head is shockingly close to the top of the MD500 body but just clears – I did have to invert each blade-grip screw in the head putting the bolts at the top of the head for the bolts to clear the top of the body. One surprise is how little pitch is needed on the 5-blade head to gain elevation, I guess 2 ½ more area on the flight surfaces really makes a difference!

Thanks for reading to the bottom of this thread – let me know if you all have any questions. I’ll post more videos and ‘final’ images once I have worked out the remaining issues.

[Tilting At Windmills]

Another update - with some rework to the tail servo arm I was able to eliminate the tail wag. Now that everything seems to be pretty close to sorted out I added back the scale tail and glued in the windows.

At this point I've flown 10 or so packs with 5:00 minute flight times each and the drive train, specifically the tail belt + the raised tail drive system, is holding up fine. Despite increased complexity of the set-up along with need for the custom parts, I do believe this to be a viable long-term solution for a 200 class scale build with a 5-blade head.

Here is the latest HD flight video - I'm reasonably pleased with the level of control and amount of vibration once the heli spools up given that the the scale tail amplifies the tail vibes:
[ame]http://youtu.be/eNin0OVemdw[/ame]
If there is interest from the forum, I can shoot and post more flight videos too.

And a few more photos:
https://www.flickr.com/photos/flickravatar/14258960283
https://www.flickr.com/photos/flickravatar/14236520762
https://www.flickr.com/photos/flickravatar/14238499394https://www.flickr.com/photos/flickravatar/14258961653
https://www.flickr.com/photos/flickravatar/14258962833

[Soccerjay]

Originally Posted by Tilting At Windmills

Another update - with some rework to the tail servo arm I was able to eliminate the tail wag. Now that everything seems to be pretty close to sorted out I added back the scale tail and glued in the windows.



At this point I've flown 10 or so packs with 5:00 minute flight times each and the drive train, specifically the tail belt + the raised tail drive system, is holding up fine. Despite increased complexity of the set-up along with need for the custom parts, I do believe this to be a viable long-term solution for a 200 class scale build with a 5-blade head.



Here is the latest HD flight video - I'm reasonably pleased with the level of control and amount of vibration once the heli spools up given that the the scale tail amplifies the tail vibes:

http://youtu.be/eNin0OVemdw

If there is interest from the forum, I can shoot and post more flight videos too.



And a few more photos:

https://www.flickr.com/photos/flickravatar/14258960283

https://www.flickr.com/photos/flickravatar/14236520762

https://www.flickr.com/photos/flickravatar/14238499394https://www.flickr.com/photos/flickravatar/14258961653

https://www.flickr.com/photos/flickravatar/14258962833

I think its awesome i really want to try a gaui 200 since they sell as cheap as chips and they look pretty darn good for 3d....the scale look is awesome but im more inclined for 3d

[domcars0]

Very nice! It fly really well. I will try your 'new' tail boom system which work with original belt!
Thank you very much.

[domcars0]

I mounted mine (a 3 blades only ) this week-end and made some tests today (without scale).
I'm still not very happy with the tail, probably due to the original tail push rod.
I found that it was difficult to adjust the belt tension, so I cut little bit the pulley support to tighten the tail holder screws easier.
Tilting At Windmills, you had really a great idea and not so hard to do with a dremel. The most difficult part was to make the hole in the pulley support.

[domcars0]

After some adjustments on tail, it was OK without the scale.
But with the scale I had terrible tail resonance that broke the tail case
Ordered a new one....

[BHChieftain]

Sweet build!!!!

Chief

[alphonso]

well done again. I copied your instructions, just fitted the fuse and flew it, I had done much testing before so was confident of the set up. It takes ages to spool down now with less drag fom the simpler mechanics, and just looks so sweet..

I stuck with the bent wire tail pitch rod as I thought it looked better than the thicker carbon rod, i had to shorten it by 5mm. Duration is very good with 450 mah used in a 4 minute flight. I programmed my Castle 25 to govern at 50% and turned the timing down, the result is a smooth and stable flight, soft collective response and crisp cyclic.

with great respect and gratitude, Allan.