I have no ties to any of this Dennis Fetters guy or the Mini 500
I ran across these postings about Dennis a few months back and started
reading all I could on the groups and the web about Fetters and this
All I can say is unbelievable....
I have read things tossed back and forth and finally found it all
encapsulated in a single source from a real reporter that actually
took the time to look into things.
I bring all of this up for only one reason, this entire history of the
Mini 500 from 1990 forward is a good example of why one must do their
homework before becoming involved in any new aircraft that will be
My condolences to the families of those unfortunate soles that
unwittingly became involved in this craft and as a result were injured
or lost there lives.
I would look forward to conversing with any parties that, were in the
employ of, or were otherwise associated with, the manufacturer of the
Mini 500 from 1990 forward.
Well, why don't you just converse with me? After all, you seem to want
to know something about it, wouldn't it have made since to talk to the
guy that knows the most about it?
The reporters and people interviewed in the story you read at the site
above just happen to be some of the most dishonest reporters writing today.
We all know Jim Campbell and his reputation, no need to dwell on that.
We all were here when the host of that web site Fred Stewart lied to us
all about his involvement and intentions. We all know that the convicted
child beater Rick Stitt was paid by Fred Stewart to spy, sabotage and
help destroy Revolution Helicopter. We all know that Joe Rinke was
trying to make his own helicopter and needed Revolution out of the way.
Everyone in the story had personal ambitions why they attacked
Revolution Helicopter, everyone knows that.
As for the reporter Lisa Brown, she came to my factory and promised to
do a balanced story, and ended up not reporting correctly on one single
fact that we gave her. Her report was completely one sided and full of
lies and misinformation. I even told that to her face after she made the
If this is what you have based your opinion on, then you don't have the
full facts. If you have posted this to make trouble for some reason,
then go have fun with it, I don't have time to play with you. But if you
posted this to learn more about the subject, then you are welcome to
email me directly and I'm happy to tell you the true story. Below is one
of the final flight reviews made by a highly reputable magazine
Kitplanes, about the flight characteristics of the Mini-500 before
Revolution was forced to closed it's doors. Read it, makes it a little
hard to believe what the others had to say.
Additional Material Not Included in November 1999 Flight Evaluation
Six Questions posed by Bill Phillips; Answers by Ken Armstrong and
The November '99 issue of KITPLANES contains the most complete flight
evaluation of the Mini 500 that we know about. The Mini 500 is a
single-seat kit helicopter sold in the hundreds by Revolution Helicopter
Corp., Inc. (RHCI) of Exelsior Springs, Missouri. Pilot/author Ken
Armstrong is a regular contributor to our bimonthly "Rotor Roundup"
column and among the few truly qualified to evaluate homebuilt
helicopters. A 9000-hour professional pilot who makes his living
teaching helicopter fire-fighting techniques around the world, he has
flown more than 40 types
of helicopters including most of the well-known homebuilts.
In his article, Armstrong acknowledges the controversy surrounding the
Mini 500, which has accumulated more than 40 accidents including eight
fatalities from among the 400+ kits sold. He describes his initial
difficulty correlating collective pitch and throttle to maintain rotor
rpm "in the green," noting that most of his flight time is in
turbine-powered helicopters with governors that do not require close
attention to power applied.
He notes the animosity that has grown between Mini 500 designer/RHCI
co-owner Dennis Fetters and some customers. A small but local group of
owner/pilots has accused RCHI of selling a kit with design and
workmanship defects. A common complaint has been incorporation of a
two-stroke engine (the liquid-cooled Rotax 582) for the Mini 500.
Numerous engine failures in the air have resulted in accidents, some of
which have been fatal.
While Fetters has contended consistently that all of the fatalities and
most of the other accidents have resulted from pilot and/or builder
error, critics have faulted RHCI for unsatisfactory customer support
including failure to develop fixes for technical problems such as
leading to cracking frames, inadequate power, and defective parts
including the early clutch systems.
In his article, Armstrong says that he finds the major technical
problems have been solved with RHCI fixes including a mast support that
smooths the rotor and an engine performance-enhancement package (PEP--a
tuned-exhaust system). Some pilots have reported that the Mini 500
pitches down unacceptably after a power reduction or failure. After
entering a number of practice autorotations, Armstrong concurs with the
company that pitchdown was not a problem with the fully equipped Mini
500 he flew. He acknowledges that operation of any helicopter is not to
be taken lightly, but he
describes the Mini 500 as having "very good handling" including its
Armstrong's article will not satisfy the Mini 500's most ardent critics,
who have castigated us for continuing to accept advertising from RHCI
for its new two-place Voyager 500, which is powered by a three-cylinder,
two-stroke engine developed for the application.
Among the critics is Bill Phillips, a retired nuclear physicist and an
airplane and helicopter pilot who has flown a Mini 500. He was elected
president of the International Experimental Helicopter Association Inc.
(IEHA), which was formed in a February '99 Florida meeting of Mini 500
owners and others unhappy with their helicopters or company response to
problems. Phillips said they intended to finance their own fixes if RHCI
did not find acceptable Mini 500 technical solutions soon. At this
point, Phillips remains unconvinced that RHCI's PEP and mast suppport
solve the power and frame-cracking problems, but IEHA has yet to offer
its own technical solutions.
Knowing about the upcoming article on the Mini 500, Phillips posed the
questions you will find below. Lacking space in KITPLANES to publish
them, we committed to what you see here on www.kitplanes.com:
six questions, comments by Ken Armstrong as he felt he could address
them, and official responses by Dennis Fetters of RHCI. We have no
illusion that this effort will change opinions of those whose views are
now polarized, but the airing of these issues is in the KITPLANES
tradition of continuing in-depth, unbiased reporting of the Mini 500 saga.
Questions and Answers
Bill Phillips: 1. What about running the Rotax at 104% continuously?
Rotax itself does not warrant this engine in this application. The
manual states that the rpm for 104% should only be used for 5 minutes,
yet the Mini 500 will not fly with most people in it unless it's run at
104%, which is nearly 6800 rpm. Rotax says maximum continuous is 6500
rpm. There is simply no margin left at 6500 rpm, and the engine is not
designed to be run at 6800 rpm for more than 5 minutes.
Ken Armstrong: RPM limits are usually related to the possibility of
overheating. In my Mini 500 flying--including extensive hovering where
the engine works hardest--heat was well within the green.
Dennis Fetters: Statement No. 1 is totally incorrect. First, Rotax does
warrant the 582 engines used in the Mini 500 and always has. Next, the
Rotax manual mentioned is for airplane or propeller installations only!
Helicopters are very different and use the power and rpm in a different
manner. All helicopters run their engines at 100 to 104% rpm while
constantly changing the power settings.
So at 104% rpm at cruise flight, the power required and used is about
70%, a normal usage. Operating at 104% rpm will not hurt the Rotax
engine in the least bit. In fact, it works better running it at a
continuous rpm and varying the power level. This will result in more
stable exhaust gas temperatures, more constant engine running
temperatures, and less carbon buildup. To date, there has not been a
single Rotax engine failure in a Mini 500 due to the overexertion of the
Phillips: 2. The use of Nylock nuts in the engine compartment? The
control pushrods are directed through an engine compartment where the
temperature gets to 300º F. on every flight. I'm not making
this up; I've measured it. This is simply not a standard accepted
practice in the aviation industry. All locknuts firewall forward must be
metal locking nuts, not plastic or fiber nuts.
Armstrong: No comment.
Fetters: First, it is not true that the engine compartment runs at 300º
F. If it did, the fuel in the tank would blow out the vents in a raging
boil, the fiberglass body would become soft and deform, and the pilot
could not sit with his back against the firewall. The use of Nylock nuts
is standard in aviation, even in the engine compartment. We have never
had a single failure or melting of one. Anywhere that gets hot, we use
steel locking nuts.
Phillips: 3. I have never seen a Mini 500 or a Voyager without the main
rotorbades warped with a forward sweep. It's probably a manufacturing
systematic error. The blades are baked with an aluminum spar in the
leading edge. They come out of the mold perfectly straight. But due to the
difference in coefficients of linear expansion between the aluminum and
the composite materials, the aluminum contracts more as the blade cools
and warps it in a forward sweep. I suspect that much of the vibration
the machine produces in forward flight is due to this unstable forward
the blade hunts and seeks for stability in the feathering axis. I've had
this argument with [KITPLANES Editor] Dave Martin. Dave uses the Blanik
sailplane as an example of a forward sweep aircraft that is
pitch-stable. This is only true because the Blanik has a tail and the
forward sweep does not cause diverging pitching moments for the whole
airplane because the tail has more
authority. Simply sweep that wing forward a bit more and it would
diverge. A helicopter airfoil has no tail. A very tiny forward sweep is
divergent in pitch.
Armstrong: In my flights, I found this not to be an issue. There was no
apparent instaility that would be caused by blades hunting.
Fetters: It is necessary to relieve cyclic and collective pressures by
allowing for the proper amount of lift to occur forward of the pitching
point of the blade, or using springs, or both. This is done on other
helicopters with a narrow and less efficient chord width, or sweeping
the blades forward. The Mini 500 blade does this with a slight forward
sweep, and their rigidity and centrifugal forces help
maintain stability. It is ridiculous to say that the blades are "hunting
and seeking" because of this; the Mini 500 flies extremely stable. Look
at many of the more modern designs such as the paddle-tip
blades. Airplane control surfaces also do this with a certain amount of
area ahead of the pivot point. The well known helicopter analysis
engineer R.W. Prouty with Rotor & Wing writes that there are
no negative effects from forward-swept rotors.
Phillips: 4. What about two-per-rev imbalance? No one tomy knowledge has
been able to balance the machine in ETL and eliminate the "two-pers."
[ETL means entering translational lift--accelerating through 15-20 mph
in a Mini 500, according to Fetters.] This has led to frame
cracking in 30 to 50 hours on the majority of the ships that have flown
that long. My guess is that the problem lies in the engine mount and the
"hunting and seeking" of the main rotorblades in ETL.
Armstrong: In my Mini 500 flying, there was no notable lateral vibration.
Fetters: It is true that the Mini 500 had a two-per-rev problem that
caused some frames to crack. This problem was solved and made available
to all owners some time ago, but still our detractors don't acknowledge
its existence. It is called the Mast Support Upgrade. The "hunting and
of the blades is not even close to having been the problem. RHCI found
the problem and made the fix available at our cost, and this problem is
no longer a valid point.
Phillips: 5. Nose-down pitch upon loss of power in translational lift
has been a problem. The horizontal stabilizer is in the downwash in
forward flight. This causes a positive pitching moment that RHCI has
overcome by essentially adding an elevator with a negative deflection.
This works fine
as long as the air is being pumped down by a running engine. At the
instant the engine quits, the downwash quits. The machine pitches over
violently. This is particularly dangerous since it's exactly
the wrong move to induce autorotation. It's important that the rotor
disk be pitched up so air can flow up through the blades and drive the
system before the inertia dissipates and it becomes
unrecoverable (which happens below 80% rpm). Many owners have told me
they have pitched over almost vertical. I suspect the boom chops have
followed from this scenario because the normal reflex is to pull back on
the stick, tilt the rotor system backward and chop off the tail before
the fuselage can pendulously respond to the disk pitch change.
Armstrong: I did not experience any significant nose drop when entering
practice autorotations. The approaches, however, were gentle and I knew
when they were coming.
Fetters: There is no significant nose drop in the Mini 500 if it is set
up right and flown correctly. Now with the Mast Support Upgrade, there
is almost no drop at all. The original problem occurred with a dramatic
nose drop after a member of the detractor group told everyone over
theInternet newsgroups that RHCI was wrong to set the negative blade tip
angle at 0.5º for proper entrance to an autorotation. Instead, he said
to set them at a negative 2.0º! This would suck down the nose of
the helicopter as you could imagine, and it flies the rotor blades 10
inches closer to the tail boom.
Also, the Mini 500 Pilot's Operating Handbook says to lead with back
cyclic before lowering the collective. Again, this was not a problem if
set up and performed right, and it has been improved
Phillips: 6. Many of the rotating parts lack castelated-pinned locknuts.
If you examine a tailrotor system on a Mini 500 or the Voyager 500, you
will find Nylock nuts again. This is just not normal accepted procedure.
All rotating parts should have hardware that is pinned or has metal locking
nuts with PAL nuts over them.
Armstrong: No comment.
Fetters: There are no rotating parts in the Mini 500 that use Nylock
nuts or all-metal, self-locking nuts. All control joints use an inner
sleeve, and the bolt and nut are tightened to full torque to
retain the sleeve. All working and pivoting is done on the sleeve, never
on the bolt. Therefore
our design is correct. It is only necessary to use a castelated and
pinned nut on a bolt that is used as a pivot, or in a place where
constant disassembly is required.
Phillips: I understand that most of the pilots who are still flying
their ships are low time. Not only that, they are low-time builders too.
Most of them have not built airplanes. Fred Stewart, Joe Rinke,
Allen Barklage and Gil Armbruster--just to name a few--never built an
airplane. They simply
assembled a helicopter and did not know the dangers or flaws in hardware
used by RHCI in this ship.
Fetters: Wrong again. Fred Stewart previously built a RotorWay
helicopter and was trained to operate an RHCI Service Center. Joe Rinke
tries to sell upgrades to Mini 500 customers and is now saying he will
come out with his own helicopter design, and he has no experience?
Sounds like an uphill battle to me. Allen Barklage had 33,000+ hours in
helicopters, and he and Gil Armbruster were expert speakers at the
detractors' meeting in Dallas in 1998. This is who was teaching about
safety and maintenance, and you are saying they didn't have experience?
While we're at it, let's get a response from RHCI on two other accusations:
1. That the company refuses customer support and parts sales from anyone
who joined the "detractors' group" (as Fetters calls them) or who joined
IEHA. Fetters flatly denies that any RHCI customer has ever been refused
support or parts sales.
2. That a $750 transfer fee is required to be paid to RHCI by any second
or subsequent Mini 500 owner to buy parts or get factory support.
Fetters acknowledges that such a policy was in effect
briefly but was dropped more than a year ago. Now, any owner who is
willing to sign the
standard purchase contract required of original kit buyers has access to
parts and service at regular prices, Fetters says.
Finally, I need to put some perspective on this tome. Ken Armstrong
alludes to the clashes of personalities surrounding the Mini 500. Here's
some insight. Fred Stewart--who helped organize the critics' meetings in
Dallas and Florida--was once RHCI's most active dealer. He and Dennis
Fetters were close friends. Stewart says he became disillusioned because
of RHCI's failure to support the product and his customers. Fetters has
supplied a pound of e-mail implicating Fred Stewart,
Joe Rinke and others in what he sees as a conspiracy to put RHCI out of
business. Some of the evidence is linked to this magazine. In early
September, 1997, Lee Sarouhan (who was at the time a pilot/sales rep for
RHCI) called in an ad to the KITPLANES classified advertising manager. The
ad recruited helicopter engineers to work on a new two-place heli at
Mid-America Helicopters--Fred Stewart's company in Barnhart, Missouri.
Stewart has said that he was simply trying to spur Fetters to develop
RHCI's two-seat trainer more quickly; he cancelled the ad contract early
and did not hire the qualified engineer who responded to the ad.
On February 10, 1998, Lee Sarouhan used his RHCI office computer to send
a personal e-mail to a relative. The e-mail said, "Well, it looks like
Revolution Helo will go out of bizz in the next few
weeks. The good news, my project Mid-American Helicopter should start up
within a year...."
Sarouhan's e-mail was found by RHCI and he was fired on February 12.
Stewart continued to deny that a business relationship with Sarouhan
existed. Rinke--a Mini 500 customer--lost a lawsuit
brought by RHCI to to prevent him from marketing a turbine engine
conversion for the Mini 500 in
violation of his RHCI purchase contract. The court ordered him not to
sell turbine systems and not to fly his jet-powered Mini 500. Bill
Phillips initially supported Fetters' position, but the two fell out
after Stewart offered Phillips a Mini 500 for evaluation. Fetters says
he felt that RHCI was being blackmailed by Phillips to supply Mini 500
parts and upgrades. Phillips and others are not convinced
that the RHCI fixes--primarily the PEP and the Mast Support
Upgrade--solve the technical