Mini 500

[bryancobb]

That's definitely C U R V E D there Hawk! Is that the ones you fly with? Mine was straight as an arrow. I don't see how you could get the ship balanced with those.

[DennisFetters]

Sorry, don't have much time to answer and can't see so good with my head all rapped up like a Taliban.

Never had a spraque clutch fail that I know of.

All blades were the same shape. They all had an 8% twist, and they all had the same warp forward. To some people the twist made the warp look exaggerated. The warp forward helped to relieve collective pressure and had absolutely no ill effect, all would balance smooth.

Belt track had to be done or you would have a failure. In the Mast Support upgrade included a belt support upgrade that made tracking the belt very easy, but you still needed to do it. If you didn't buy the upgrade then it was still going to be harder to make the correct adjustments.

Using the 4 rubber plugs around the bearings to hold the bearings from turning was my stupid idea. People would not install them right and cut then too long, and it could fail the bearing. My newer designs all have an oring in a grove in the housing that holds the bearing. Never had a problem with the new design.

The company selling us the plastic "Tee" changed the material and never told us. As soon as we found out about it we sent new Tee's out to those customers that had received them for free.

Bryan, I was not directing my comments toward you. You need to not be so sensitize. And, you also need to stop speculating on why I'm in China. I'm not building kit aircraft in the USA because I don't want to sell to and deal with you all anymore. I learned a big lesson about trying to build a helicopter for anyone to afford. It can't happen because what I do is too technically advanced for the normal guy to assemble and make fly correctly.

The fact is I didn't design a perfect helicopter for my first helicopter and I made a few mistakes. Nor did I ever have a prefect customer that assembled their machine correctly the first time around. I did correct all of those mistakes. Off hand, I believe there were around 20 AD's or so.

In comparison, here is what I could find on-line for the factory built R-22 helicopter, built everyone by a professional, and it wasn't Franks first helicopter to design.

113 Service Bulletins
62 Service Letters
11 Special Service Letters
5 Safety Alerts
35 Safety Notices

Maybe it will give some of the more open minded people an idea of what I was up against, and just maybe cut me a bit of slack and an ounce of respect. I'm going home to China now. More later.

[bryancobb]

Hi Dennis,

I am not hypersensitive. Nothing on the Mini-500 was outside the NORM on new helicopter designs. They all have teething problems. ALL helicopters are too complicated to build, for the "average joe." Certified helicopter builders overcome this by TRAINING their employees on a small slice of the building task.

Experimental kit manufacturers have to deal with the fact that some of their builders are smart and talented, while some are dumb and clumsy. Some builders are willing to BE TRAINED (by a good build manual/internet/videos) and some builders think they know everything and don't need to be told.

"And, you also need to stop speculating on why I'm in China. I'm not building kit aircraft in the USA because I don't want to sell to and deal with you all anymore." That is EXACTLY why I thought you were there. No disagreement.

"All blades were the same shape. They all had an 8% twist, and they all had the same warp forward." That is the FIRST time I ever heard you say the forward sweep was "designed-in"?

I said that I was saddened that the Mini-500 didn't get a chance to finish the "teething process," and become a big seller.

[Tim B.]

Feel the love?







does anyone know where ALL ADs and whatever else was issued concerning the Mini 500 would be? Would be cool if they were all in one place and not have to search 1000 different sites. Be gentle, not trying to pick a fight. I am just wanting to read up on this kewl little ship.

[Barney Bahle]

I believe John at www.millenniumhelicopters.com has them all listed. Lots of good stuff there.

[bryancobb]

Originally Posted by Tim B.

Feel the love?







does anyone know where ALL ADs and whatever else was issued concerning the Mini 500 would be? Would be cool if they were all in one place and not have to search 1000 different sites. Be gentle, not trying to pick a fight. I am just wanting to read up on this kewl little ship.

All of them are here...
http://www.millenniumhelicopters.com/page9.html
http://www.millenniumhelicopters.com/Notice0004.pdf
http://www.millenniumhelicopters.com/Notice0005.pdf
http://www.millenniumhelicopters.com/AD%20050198.pdf

[Tim B.]

Thanks

[C. Beaty]

At least some of the problems of the Mini-500 were solved by a proper rotor:

http://www.rotaryforum.com/forum/sho...light=Mini-500

DragonWings rotors are essentially the same airfoil used on the BO-105 helicopter with a slightly different meanline; NACA 2312R Vs. 23012R.

DWs are also part of the reason for the outstanding performance of the Mosquito helicopter.

[Barney Bahle]

Since we're talking about blades here, I've got a question about the Mini. Rotorway, Helicycle, and even The Mosquito have a lead lag adjustment. How dose the Mini get by without it? Just something I've often wondered about.

[bryancobb]

Two blade rotors do not lead & lag. What you are talking about is an adjustable link to the trailing edge that you adjust to "sweep" a blade to balance the rotor system in the "CHORDWISE" direction.

The way Dennis designed the head, was to eliminate complexities. The two pins that hold the blade in the grip, theoretically put them 180 apart and held them there.

On the Mini-500, chordwise balancing is done by using shims up at the head teter pins, called "spuds," to SHIFT THE WHOLE ROTOR SYSTEM.

This has the same effect as "sweeping" one blade forward, and the other blade aft.
I.E. Moves the center of mass.

[DennisFetters]

Originally Posted by C. Beaty

At least some of the problems of the Mini-500 were solved by a proper rotor:

http://www.rotaryforum.com/forum/sho...light=Mini-500

DragonWings rotors are essentially the same airfoil used on the BO-105 helicopter with a slightly different meanline; NACA 2312R Vs. 23012R.

DWs are also part of the reason for the outstanding performance of the Mosquito helicopter.

Well, that's really not true, they solved no problems. I sure am glad to see that you deleted the other posts where you said that the Dragon Wings improved the overall flight capabilities of the Mini-500, because that was not true either, but you caught that?! The Mini-500 was only flown in a hover close to the ground with Dragon Wings, as you stated in the thread referenced, so no claims can be made other than maybe better hover.

There is a reason why I used the airfoil that I did. There is more to designing a helicopter than for just to achieve it's maximum hovering capacity. You must look at the overall performance, and sometimes rob from Peter to pay Paul, as were to say. Nothing is for free, all is give and take, there is no free lunch. Where you improve at one point more times than not means you have to take from other points. So is the life of designing helicopters.

Yes, it is possible to improve the Mini-500's hover with a different airfoil, but at the cost of something else. The Mini-500 hovered very well with the airfoil I designed, but when fully loaded, as like any helicopter fully loaded, it was sluggish, but once in flight performed well in it's other functions.

Yes, it is possible to improve the Mini-500's authorization, but again, at the cost of something else. But, as it was, the Mini-500 autorotates very good. People all the time say how good it autorotates.

Here, just watch the Mini-500 video. It's all real flying with stock Mini-500s, no smoke or mirrors, and even without the PEP back then, so it even flys better than in the video now! Does it look like it's having troubles? It's being flown by some hefty boy's as well. Flights also included at Sun & Fun on hot days, and in Brazil;


The Revolution Mini-500 Helicopter demo Video "Part 1" - YouTube


Here is the second part of the video;


The Revolution Mini-500 Helicopter demo Video "Part 2" - YouTube


The fact is, the Mosquito using the Dragon Wings is a lighter aircraft than a Mini-500, and has the same horsepower, yet it is not even close to the same top-speed as a Mini-500, nor at top speed is it nearly as smooth as a mini-500. Just watch one fly by and see the skids shaking. There is a reason for that; Because I made the right compromises to give the Mini-500 good hover and auto-rotational performance, and to still have a high top speed and low vibration. The Mini-500 is a go-somewhere helicopter, and not just a putter-around-the-field helicopter. And that is due to the type of rotorsystem I designed.

[bryancobb]

I watched that "little guy" (foreigner) flying the factory (red/white/blue flag) helicopter at Sun-N-Fun in 1997 or 98, doing OGE hovers at 200 ft, and If I remember right...he SHUT THE SWITCH OFF, and did autos from a 200' hover!

I had a video of it but I can't find it. I had never seen a helicopter do that! When the engine was cut, he'd dive forward to 40-50 MPH and then flare JUST IN TIME for the 10 MPH slide to a stop.

[DennisFetters]

Originally Posted by bryancobb

I watched that "little guy" (foreigner) flying the factory (red/white/blue flag) helicopter at Sun-N-Fun in 1997 or 98, doing OGE hovers at 200 ft, and If I remember right...he SHUT THE SWITCH OFF, and did autos from a 200' hover!

I had a video of it but I can't find it. I had never seen a helicopter do that! When the engine was cut, he'd dive forward to 40-50 MPH and then flare JUST IN TIME for the 10 MPH slide to a stop.

He was from Italy. The best pilots I've ever seen are from Italy. Yes, he could do stuff that made my hair stand on end because I could never be that good. And again, all that before the Mast Support upgrades and the PEP. Imagine the show he could do with more power and torque! Some of his flying is on the video in the Red-White and Blue Mini-500s at Sun & Fun. Maybe on the second part of the video, which gives you the option of watching at the end of the first part. I guess I can post it above too.

[C. Beaty]

Rotors with superior lift/drag ratio improve performance of helicopters in all flight regimes:

20 ft Hovering Autorotations in the Mosquito XE Helicopter - YouTube

[WaspAir]

Originally Posted by DennisFetters

The Mini-500 is a go-somewhere helicopter

Where did they all go?