Ben Showers Skytwister plans built helicopter
The SkyTwister started out as a modified Adam-Wilson hobby copter designed in 1956 which was originally powered by a 650 triumph bonnivlle motor cycle engine of 40 h.p. At the time Ben was building the sky twister, he (Ben Showers) ,a gentleman known as "Animal" and Jim Hodges of N.J. where all in a race to see who would get one flying first. Animal had a 750 cc Honda engine in his running 269 hughes blades while Jim installed a Mazda rotary 12-A auto engine into his.
Ben got his to fly first, and now the one Animal was building is in a private museam in hubbard org. owned by Jack Lenhardt. Animals Honda powered helicopter would try to hover but the clutchs would not hold the main rotors load. Jims was completed and while heavier, had alot of power, but little is known about whether it flew or not.
Ben had many failures with the SkyTwister helicopter during it's development, he tried experimenting with different things including multi-blade tail rotors and other ideas that contributed to more then one to many forced landings. The unfortunate side of R&D when building and test flying your own helicopter from scratch. He (Ben) tought himself to fly it in a short time, and has recorded lots of video footage of him doing his early tests. In the video you can easily see it had good power and seemed real stable.
He once performed a public demonstration of his SkyTwister flying it at the Mountain City Fly-In around the mid 90's. At some stage during it's development Ben encountered a sprag clutch failure which left him injured for some time. This only drove Ben to refine the SkyTwister helicopter further and add safety improvements outlined in the following articles. What the end result was can only be seen as one of the cleanest looking scratch built helicopters of it's time. (See Harold Wenrich's SkyTwister "H")
If you are interested in persuing this helicopter design, you may be able to track down more information through this Yahoo Groups forum: http://groups.yahoo.com/group/Helicopter_Forum/
Last known details for Ben as of the late 90's were: Ben Showers Aero, 1040 Skyview Drive, Milton, PA 17847, USA. He was selling plans back then though it is unknown if they are still available for purchase.
The following is a complilation of a series of articles and reports from different sources.
Courtesy Homebuilt Rotorcraft Magazine, July 1993
During hover attempts, and all hover practice, the A-symetric "flat bottom" blade is probably the finest rotor blade that you could ever use. However, a "WARNING" follows.
Ben Showers has become a very proficient pilot with his Choppy SkyTwister A/W.
He has done some absolutely fine maneuvers with this A/W. However, upon forward transitional flight, he has encountered some terribly frightening sequences of events.
The A-symetrical flat bottom gyro blade is strictly for gyros. Both Ben and myself have found this out.
When you mount this type of blade to a semi-rigid rotorhead, and vary the blade pitch requirements, such as on a helicopter, by using the collective to change pitch through push tubes, what you are really doing is changing the "Centre of Pressure" on these blades and it can be deadly if you haven't gone through it.
Your first encounter with this situation will begin as soon as you begin transitional flight.
As you begin to leave the "cushion" and add throttle and a little collective, you will go - immediately - into a very hard right yaw, and as the yaw increases with collective you will become of with the "angel" if you can't correct immediately.
Gently lower the collective, and get the ship into a hover as soon as possible.
On symmetrical blades, the centre of pressure is variable, hence the reason they fly so good.
Again, the flat bottom blades are great for hovering, or slow manouvers, however, they are not for semi-rigid rotorhead flight.
For Ben Showers and myself, this has been a REAL learning experience. Don't attempt this stuff, let someone else go first, and if they live ... pay very close attention to their words of caution, for it will be they who dare, and try to give their knowledge to those who will listen and heed.
EDITORS NOTE: These differ to the more modern "reflex" style blades now used on some kit helicopters eg; Mosquito Kit Helicopter.
CHOPPY GETS HIGH
Courtesy Homebuilt Rotorcraft Magazine, October 1993
It has been a great summer here in Pennsylvania and flying "the pattern" is now past history! I fly my helo on average of once a week. The only major change that I have made since the last article was the rotor blades. A newly aquired friend in Utah, by the name of Kent Culver helped me out with a set of 269-B Hughes rotors, which when modified to fit the A & W, proved out to make the Choppy a great flyer. Since, I had to change and "beef up" a few things along the way. But that's to be expected.
There has been great interest in my helo and I have made contact with people all over the world. The farthest being Athens Greece! Along with flying a machine I hand built and meeting and talking to new friends, this project has turned out to be a Fantastic Voyage!
It's sad for me to write my final article, but glad that things have worked out, and I accomplished finding the combination I needed to make my dreams come true.
My word of advice to others that may follow, is to take your time, almost to the point of dragging it out! I have said it before and I'll say it one more time before closing. (Haste makes Waste) And one more final note. Every time I strap myself in my helicopter, I am preparing myself for another LESSON. When I cease to feel that way I will quit flying.
'Till we meet again, lets all Fly Safely.
This article will conclude the series of articles I have written on my helicopter project! I have other projects and it's time to FLY and enjoy my little "Choppy".
SKYTWISTER UPDATE July 1995
Courtesy Homebuilt Rotorcraft Magazine, July 1995
"We also learned that Ben Showers, developer of the SkyTwister helicopter also crashed and sustained severe. Initial rumours of the accident ranged from Ben being in a coma to Ben being killed. According to his associate Jim Hodges, he is recovering from a broken back and several ribs.
The SkyTwister was totally destroyed in the accident, but Ben is already working (fromhis wheelchair) on a new "improved" ship. Jim said Showers will provide us with details of his accident in the near future."
Courtesy Homebuilt Rotorcraft Magazine, July 1996
I guess you all may wonder how ol' Ben Showers is doing? Well, pretty good I would say. I am working on many "SkyTwister" parts and am rebuilding my own prototype. I will be testing a new design light weight composite landing gear that will absorb more energy in the event of a hard landing (that resembled a crash) similar to what I experienced a while back.
I am working with crutches now, which gets me out of the wheelchair. I have been flying, and doing some hover work with our new Hirth air-cooled model H "SkyTwister".
There is much interest in this aircraft and could possibly end up being a "Kit Kopter". But as I have been telling everyone, I will not make something available to the public, that I haven't tested and "flown off" a couple hundred hours at least.