Bergen Turbine Startup - Blades Remain Stopped at Idle

[WillJames]

Most everybody who knows and flys with Greg knows he VERY rarely waits until he gets to the flight line to start his machine. He does it out of the pits but before the flight line where there are people around to man the safety equipment, before he carries it out to the flight line where only his spotter is allowed to stand with him.

I have flown with Greg, and also flown his Turbine a few times, and the blades never start turning until you increase the throttle above idle.

[Greg Alderman]

Thanks Will...had a request from someone to show that the Bergen doesn't have it's blades turning at ground idle...of course...at flight idle the clutch is engaged and the blades are turning...

[chopper jockey]

Yep, ok thanks Greg. My vario won`t do that, the clutch drags unless I reduce the idle to 33,000 rpm. :roll:

[WillJames]

This Intrepid Turbine Demo video I shot at IRCHA SE also shows the Bergen at idle and the blades stopped. I have more video of it withthe blades stopped and Greg carrying his to the flight line, but it is not on Hard Drive.

http://www.augustoheli.com/videostuff/videoarchive/HelifreakArchive/C/ChrisBergenIntrepidTurbineIRCHASE05.wmv

[Gary Travis]

The vario clutch is designed for the gas engine which spins at a lower rpm, on the wren system the output shaft of the gearbox spins at a higher rpm there for engaging the clutch quicker. Instaed of lowering the turbine rpm get a clutch blank and reconfigure it to engage at the higher rpm and problem will be solved.
Gary

[WillJames]

Here is another video showing the Intrepid idling without the blades turning. This video was the debut of the Intrepid Turbine at Birmingham Event 2005.

http://www.augustoheli.com/videostuff/videoarchive/HelifreakArchive/I/IntrepidTurbine1.wmv

[chopper jockey]

Gary, :lol: Lets continue here, The clutch I fitted to my turbine acrobat was the nitro version, designed for 80 size glow engines...

with regards to these videos, very nice, nearly there, but I still have not seen what I want yet.

[Gary Travis]

I would think the glow clutch is not stout enough and is engaging to soon, this is a problem trying if you get a cltch blank or make one you can modify it to engage at different rpms. Not hard to do but you will most likely go through the trial and error until you get it right. If your clutch is set to engage obove the rpm that the output shaft isd turning at idle the blades will remain stationary, also when the engine returns to idle (lower rpm at the output shaft) the blades will stop.
Gary

[Gary Travis]

Do you think maybe the glow clutch is to weak for the system and engaging to quickly?
Gary

[chopper jockey]

well ok, there could be a problem with the clutch, I could try another one. Of course I took the easy option and did away with it alltogether. At the time I needed it because of messing around with the propane on start up, now I have kero start I don`t need on board gas or have to stand anywhere near it on start up :D

[Gary Travis]

I think you would be better off going with the Benzine clutch, just make a collet the size of your output shaft that fits into the stock clutch assembly. It is quite a bit more heavy duty. If it still engages at idle just make a modified shoe to engage at a higher rpm. Pretty easy way to do it. I have found that some times using existing available parts works and sometimes they don't.

Gary

[cbergen]

Well, unless we specifically do a video just to satisfy your (a business competitors) curiosity, you'll just have to take our word for it!!

This system has already been shown and approved by the AMA as meeting their guidelines.

If you really want to see how it works, you can certainly order one from us at Bergen R/C.

[chopper jockey]

Gary, yes I will try your suggestion, I could mill slots in the shoes to make them lighter, which will make them engage later, good :idea:
Chris, I think Greg has already suggested he would do a video clip, just for me. :) :)

[Greg Alderman]

Yep, ok thanks Greg. My vario won`t do that, the clutch drags unless I reduce the idle to 33,000 rpm.

I thought this meant you were satisfied...I had already given up the idea of doing any more startup video...that one was boring enough! :D

[Dr.Tim]

The Oddysey Clutch (Vario) Does Not engage at Idle ... Although I an comparing apples to oranges .... Gearbox to non gearbox turbines sort of speak .. The Jakadofsky has an internal gearbox not a second stage gearbox to clarify. .. This system has been flying now for a couple of years without any problems at all.

Dr.Tim

[cbergen]

You want us to design a clutch for your conversion also?

Send me some numbers, I'll see what we can do.

[chopper jockey]

:lol: :lol: nice one

[Dr.Tim]

Sure would be nice of you chris :cool: But you forget .... ours is Not a conversion. It was built from the getgo as a Turbine helicopter but, Always looking to improve the product! Any help would be nice .... does that mean I have to let you fly it again? :mrgreen:


Dr.Tim

[Heli_jack]

Even with all this, what does the Wren need to idle at? My Jaka, one of the oranges :lol: , idles at 30K just fine. 33K for that matter, my clutch doesn't engage until I hit (about) 38K.

That being said, obviously with the smaller MW54 the idle would be higher, but how much? Does it hurt it to idle slower?
Jack

[cbergen]

Not you, Tim!! You're clutch system seemed to work fine also. Can I fly it anyway? :D

Recommended Idle is 45,000, and that's where I have mine set.

[chopper jockey]

Jack,
according to the operating handbook, green apples are supposed to idle at 45,000 and suggest 50,000 rpm for a quicker response. :)

[richie1967_uk]

I am just doing some tests with my new Cuatro, the wren idles at 45000 with the blades stationary no problem (using MAH 810s). Greg, i know you use the same blades on your Bergen, what pitch do you hover at and what throttle curve are you using? (asuming the info is not a secret!) Also what do you have your Max rpms set at? I am aiming for a head speed of around1 1500 rpms, at this speed the heli is hovering around 3-4 degrees pitch which seems a little low! I have yet to add the two metal fuel tanks so i guess the added weight will require a little more pitch. Another question i have is regarding the gearbox, it runs very smooth as expected, and maintains a healthy 45 degrees C while running. As expected the temp creeps up after shutdown, I have noticed however that the heat also conducts from the gear box via the shaft to the clutch bell and thus the belt. It means the belt is getting hot in one area as the whole system cools down. Anyone had any issues with this? I must say i loved the wrem predator, but the cuatro is even better!! Maybe one day i can afford the Bergen!!

[Greg Alderman]

Richie...nothing secret about my throttle and pitch settings...except don't forget that unless the final gear ratio is the same as my Bergen Turbine the throttle curve will proably be much different....

As for pitch...honestly I have no clue...I am one of those guys that set zero pitch at Mid-Stick and then set both positive and negative pitch to what I want (+-12 is what I am using on mine) and then go fly...I then adjust the throttle curve to give me the head speed I want and never touch the linear pitch curve again...so...like I said it hovers at what ever pitch it hovers at! I don't have a clue where my stick is at hover either...I would think from the feel it is a little less than 3/4 sitck in an upright hover...and a little more than 1/4 in an inverted hover...

The only throttle curve off the top of my head is my "Normal" flight mode...which I just have a straight linear line from 0 to 100...and that seems to work out to be about 1450 head speed in a hover...I think my Idle-up curve (1650 head speed) is around 60% at zero pitch and around 80% at hover...then just linear up to 100%...

again there is a good chance these settings might be way out to lunch for you...depending on grear ratio and total weight of your bird...


I didn't mess too much with the FADEC settings...Idle at 45K, Max power at 137K

[wolfdad]

Ok gang, I can do two things here. First of all, I have spotted enough for Alderman to last me an entire lifetime and I can say that (and, this is as recently as two weeks ago when I was at the nose of the aircraft watching the start temps on the EDT and that just ain't possible with the blades moving) that Greg's Bergen turbine blades sit absolutely still at idle. And, if you won't take my word, then I will be happy to do a video of the Bergen turbine with the OF 4 blade head sitting perfectly still at idle. Both of my Jaka's will do absolutely the same thing.

Phil, exactly what do you want to see....the blades come to a stop at idle, the blades stay stopped at idle or what?
Doc

[chopper jockey]

Hello Doc, nice of you to chip in here, there is nothing sinister going on, I`ve fitted a standard vario nitro clutch to my acrobat and it drags when the engine is idling at 45,000 rpm unless I hold the head. All I would like to see is another model start up and idle at 45,000rpm without the clutch grabbing, then wind up and return to idle and watch the head stop whilst the engine is still idling. I know the single stage turbines do this, but I`ve yet to see a 2 stage do it un-aided. In your case dock, to help things, just a ground wind up to spin the rotors and then back to idle, maybe leave the gas connectedif it`s easier. I`m not saying I don`t believe anyone here and I`m not calling anyone a liar, an other was suggesting that, not me. :)