4-Blade Bergen Turbine and Blade Stop Issue Resolution

[wolfdad]

Below are a couple of videos that may be of interest to a few.....or many. The first video is of my Bergen Turbine equipped with the OF 4 blade head and 800mm OF blades. Not any flying this time around due to me having to learn a lesson a second time, however the video may be of interest to those considering equipping a Bergen with the 4-blade head.

The lesson learned is that, when/if you change to a 4-blade head, the huge increase in torque has to be taken into consideration According to one of my mentors, Peter Wales, with a 4-blade head, you will less than double the lift for the same size blades from a 2-blade head, however you will more than double the torque. I was presented this lesson with the BK, however, I had it reinforced with the Bergen using the 800mm blades. The 110mm tail rotor blades just did not have the ooompf to counter the torque. I could not go up in size on the TR blades due to clearance issues, so I was left with either going with a longer tail boom or decreasing the size of the main rotor blades and increasing the size of the TR blades, which was the choice I made. After discussing the matter with Al Wert out at Starwood, I elected to go with the 675mm mains while going to the MAH 130mm TR blades. Should have video and results this weekend.

Also, I mounted Joel's Helitronix mixer and two CSM 180 ICG gyros on the elevator and aileron channels. With the Bergen, this was pretty straight-forward. I have since changed the mount position on the gyro's and will provide details later.

Another point that should be noted in the first video is the fact that blade stop (dead stop) at turbine idle is vividly demonstrated during the first video. This is NOT a Bergen video, but my own and, hopefully, will put to rest any remaining "rubs" and "innuendo" with the Bergen Turbine. You will see, after I select throttle hold, the blades continue to wind down (it takes the Bergen forever to wind down, especially with the intertia of the 4-blade head), however you will note the tail rotor comes to an immediate stop indicating disengagement of the clutch and tail rotor drive.

The second video is entertainment only and shows "little brother," Greg Alderman putting his Bergen through its paces.

http://www.navyspecialoperations.com/Bergen/bergen_turbine_fourblade_headstop_041606.wmv

http://www.navyspecialoperations.com/Bergen/bergen_turbine_alderman_loopsandrolls_041606.wmv

And, to the guys and gals out at Wichita this weekend, have a super time. Wish we could have made it, however, if we don't see you sooner, we'll see you at the Nats.
Doc

[chopper jockey]

Nice one Doc, Thanks for taking the time to show me a 2 stage turbine with a clutch working correctly at idle. I presume the idle was at 45,000 rpm. You certainly have made you point, no doubt remaining in my mind about the clutch.
Do you however think this is in line with the wording from the AMA stating that the main blades must be stationary whilst the turbine is at idle? I saw the tail rotor was stationary but it`s clearly not practical to have to stop the main blades as soon as the turbine returns to idle, during this time whilst waiting for the blades to slow to a stop, it would seem it is not complying with the AMA rule, because of the autorotation clutch allowing the blades to continue to rotate "for ever".
It appears to me that in order to comply with the AMA rules,(the main blades must remain stationary whilst the turbine is at idle) a rotor brake must be fitted, so that the blades will come to a stop as soon as the clutch no longer drives them.
To me, this rule from the AMA is discrimination, (why doesn`t it apply to turbprops?) silly, impracticle and should be aimed at other types of engine.

[wolfdad]

Precisely in line with the spirit and intent of the AMA's changes. I can certainly make another video of the blades spinning all the way down to a stop, however, and quite honestly, I have better things to do with my time than waiting for blades to stop or continuing to argue this rule.....'nuff said as far as I am concerned.
Doc

[cbergen]

CJ, if you use a little "common sense" here, the idea is to NOT have power going to the rotor system while the turbine is running at an idle.

This is no different than any other helicopter, whether it's powered by Gas, Nitro, or kerosene. Unless you happen to NOT have a clutch.

I very much doubt that they are just being discriminatory to "your" brand of heli or conversion or whatever it is that you sell. Get over it, put a clutch in your bird, and be happy.

[wolfdad]

Chris,
Although not mentioned in words with the AMA, I think relief is spelled C L U T C H.

CJ, absolutely no offense intended, as you market a well-made and well-engineered aircraft, however our governing agency has spoken and that's what we have to live with and abide by. My advice would be to spend time coming up with a solution that meets our regulations vice arguing what we and/or you are not going to change. Or you could have a comparable "Boston Clutch Party" to our Boston Tea Party :D :D

Doc

[chopper jockey]

Mine is not the only clutchless system out there, there`s also the zealous and a german brand aswell. The way ahead has been identified as not needing a clutch with the 2 stage turbine. When more than one manufacturer`s latest design leaves out an unnecessary clutch in the name of progress and reliability, who are the AMA to hold it back, perhaps then, in the name of ignorance? This ridiculous rule, made by the AMA just goes to show they don`t know what they are talking about, in my opinion. It appears the rule may be interperated in the "spirit" of things and can easily be mis-interperated for the convienence of whoever. Therefore, if you don`t have a clutch, don`t idle the turbine, just start up, spin up and fly, then land and shut down without idling, then it would appear to be in line with the rule. what a load of BS. LMAO

No offence to anybody but the jerk in the AMA who dreamed up this rule.

[cbergen]

We can't use aluminum blades either. :shock:

I think it's a safety concern with the AMA, most of which probably came out of the body known as the Jet board, which I must confess my ignorance of, except that it is made up of some of the more experienced Turbine people here in the US.

It's very simple really, If you want to be able to fly your helicopter at an AMA sanctioned event, you may want to put a clutch in it. If not, don't! This shouldn't prevent someone from buying your heli's, unless they also want to fly at AMA sanctioned events. What they do on their own, in their own backyard, is their business.

[chopper jockey]

Let me guess, the turbine board are very experienced at fixed wing turbines, right?
so why are they makings heli decisions based on ignorance? This is why I described it as discrimination :roll:

[MarkWebber]

Having complete ignorance of the AMA rule making procedures, I can only ask..is there no way of petitioning for a variance on this rule? Personally, I can't see any reason that a clutch would be required on a turbine when one can remote start it. JMO

Mark Webber

[cbergen]

CJ, I believe that's what's known as "your opinion", not discrimination. I happen to agree with the intent of the rule, and happen to like the way the clutched system works.

If I need to track my blades, or maybe just want to take a close look at the operation of the Turbine while it's running, I can. If I want to make changes to the programming in my radio, I don't have to worry about the rotors sitting there spinning, under power, while I do so. I can even have my dataport hooked up to the ECU and get realtime information from it while I start, ramp up, and idle the Turbine, all without worrying about getting hit in the head from the blades.

Face it, the rule won't change anytime soon, so that leaves you and the other "clutchless" systems out there with a dilemma. Change your system or live with reduced sales in the US.

Fine by me!! :D

[MarkWebber]

Now, now Chris...Play nice :D

or not :twisted:

Mark

[cbergen]

This is nice!! You don't want to see me be "not nice"!! :wink:

[MarkWebber]

Got ya...I know you've been round and round on this one and probably grow weary. I really wanted to see more of that 4 blader flying but I guess we had to waste more time on this clutch issue. :?

Mark

[WillJames]

Pardon my ignorance of turbines, but from a safety and continuity standpoint, since most people don't start with Turbine helis, why would you not want your turbine to work just like every other glow/gas heli that new turbine buyers have learned on, are used to, etc... and have a clutch? Seems like this would make it a lot easier and safer for the people who purchase them as well as the people who attend the events or fields where they fly. As I said before though, I am completely ignorant about Turbine design.

Is weight really that big of a deal, or why would anyone not install a clutch in their heli? I'm not putting anyone down, just wondering why no clutch. Are there benefits to not having a clutch on a turbine machine?

[Heli_jack]

We as turbine pilots, under the wings and protection of the AMA, have rules we have to follow. These rules were in place BEFORE your helicopter first flew. They separate out fixed wing and rotory wing.

Discriminate? The plankers are the ones who should be screaming. They have to document 20 flights a year, have that signed by a turbine CD or turbine waiver holder for renewal EVERY YEAR. Us rotory wing dudes just have to pass the testing and keep our membership up. Do not have to document even one flight........that is discrimination.

The whole turbine waiver process in the AMA will need to be reworked in the future. Remember this is a new facet to the AMA. I remember when any turbine engine was not allowed, nor pulse jets. So, times change.

Personally, I like a clutch and would not have a system without one. Regardless of what the AMA or the Canadian or British counterparts say. Heck you Brits drive on the wrong side of the road too. :mrgreen: :mrgreen: :mrgreen: :mrgreen: :mrgreen: :mrgreen: :mrgreen:
:hug: :hug: :hug: :hug:

Not to harass, just to opinionize.
Jack

[chopper jockey]

Mark, I contacted the AMA, asked them to explain why and they would not respond.

Baja, a clutch is a necessity for starting a heli with an IC engine, you have to hold the head and use a starter. With the event of a 2 stage turbine with remote electric kero start, you can stand at a safe distance whilst starting and have no need to hold the head, so no clutch is required. Now that`s what I call safe! It`s a bit silly to purposely add a clutch in this way, just because pilots are used to starting up whilst holding the head, then carrying their heli to the flight line with the engine running (old habbits die hard). It is usefull sometimes to have a clutch, as Chris stated, but remember a clutch is something else to wear out and something else to fail, believe me. If I wanted to adjust my ecu settings, I would do it with out the turbine running. If It takes so long for the blades to stop, why not shut down anyway, surely that`s safer than standing so close to a running turbine? Chris, if you stand that close, no wonder you are worried about being hit in your head with the blades.
Jack, you are right, the AMA rules were in place before our design first flew, and were relevent to the engines of that time, before the 2 stage turbine was fully developed by Wren.

[WillJames]

Baja, a clutch is a necessity for starting a heli with an IC engine, you have to hold the head and use a starter. With the event of a 2 stage turbine with remote electric kero start, you can stand at a safe distance whilst starting and have no need to hold the head, so no clutch is required


Remote start is cool, that is what I like best about my big Electric machines. ;)

It`s a bit silly to purposely add a clutch in this way, just because pilots are used to starting up whilst holding the head, then carrying their heli to the flight line with the engine running (old habbits die hard). It is usefull sometimes to have a clutch, as Chris stated, but remember a clutch is something else to wear out and something else to fail, believe me.

I think pilots like the ability to stop the rotor head without shutting down the engine. Modern clutches are great and very long lasting. Not something I personally worry about.

Thanks for explaining, it is interesting to get to the meat of this debate for people like me who are not in teh know.

[chopper jockey]

Baja, thanks for the positive feedback :) , tell me, does your large electric have a clutch? will the electric motor idle with out the main blades turning?, and if it does have a clutch, would you adjust your tracking etc with the motor running?

[WillJames]

No the Electrics mostly do not have clutches, but with the power levels we are running and the new packs we are running, clutches are being considered by some people.

All I have to do to stop my rotor blades at any time is to click the hold switch. Electric motors do not have idle, they produce power or they don't.

I know of no other way to adjust the tracking than to have the machine hovering. You can set zero on the bench, but that only gets you close.

When I fly, if I hear any noises (or if I need to scratch my nose or shoot the shit with my buddies) or any thing weird, I hit hold and auto the heli down for inspection. Then take back off and fly if the checkout is OK. I would personally not be interested in shutting down then restarting a gas/glow/turbine engine every time I needed/wanted to stop the blades from turning.

I am one of those people who practices autos all the time, if I get a Turbine I will definitely be autoing it as well. Autos are a big part of flying for me.

[chopper jockey]

yes, I auto mine almost every flight, I set the engine to idle like everyone else, there is not enough thrust from the turbine to sustain a hover or take off again unless ramping back up. Anyway, so electric turbines don`t have a clutch then?
are they allowed to fly at AMA events? :?

[WillJames]

Electric turbines? :dontknow

You lost me there CJ.

[Greg Alderman]

CJ...this topic is really getting silly...I think it is time to move on... :arggg:

[chopper jockey]

an electric turbine is an electric motor! I don`t think this topic is getting silly, I do think the rule from the AMA is silly and they are discriminating against turbines, when electric helicopters don`t count. Do you really think it`s any different to get hit in the head by an electric powered blade instead of a kero powered blade? :arggg:

[WillJames]

when electric helicopters don`t count.


Is this guy for real? Have you ever flown an electric heli CJ? The only reason you would ever need/want a clutch on an E-Heli is to save wear and tear on the geartrain or drivetrain ina really hot machine. We have packs and motors now that are pushing the limits of the drivetrain of the E-Heli Designs.

You are definitely not going to get the AMA to change their mind with arguments like this, IMHO.

[chopper jockey]

My beef is with the AMA, not anyone here, please don`t take it personally. The AMA would not even reply to my e-mail. I suppose I`m trying to be heard and voicing an objection on a heli forum is one way of doing it. :roll: