It   seems like fly-by wire is the current buzz  term.

And the  advantage of  the throttle-by wire is??????, in   aircraft
applications.

Having been  the recipient of a  possible  throttle jamming incident in the
air, with a  linkage  that did not  give me good feedback of the  actual
connection   of the throttle  and the throttle body,  unless there is a
really  good
reason,   other than "that  it is available",  in aircraft  application,  I
think  I
would rather go with the push-pull  direct connection  variety  of control.

Someone please straighten me    out

Rich

--

Rich, This is not to "straighten you  out"  but  it's why I'm would like to
at least give it a go at  doing   this.

Push/Pull direct connection is very nice,  particularly when  it's  to an
engine just up front of you,  however sometimes the engine  like in  my
case is behind you and  the cable runs become quite long. I  need have  to
have 2  throttle controls linked together, it's a Tandem  Machine and   I
need enough space for people like me - 2 metres tall,  6'6" in  the  old
measurements.

I really hate having connecting   rods on the left  side of the seats like
some others have done and  the  machine is pretty  open. If I use a rod
system to join the  throttle  controls then it sits out  in the open, is
easily  damaged or tripped  over and makes it very hard to  get in/out  the
left side of the  machine, I would really like to able to  get  in/out the
left side of  the machine. So to avoid this issue  and I really  want to
avoid it, I  need use at least one  push/pull cable to link the  two
throttle levers  together so  they operate together and then  another
cable from one of  the  throttle controls to the throttle body, now  I'm
certainly able  to  do that and if the electronic control does not  work
then I  will be  doing just that.

However, TK insists that he  really  wants to test  his throttle
controller design. He is also pretty   certain that it  will be perfectly
reliable, so one must give a fair  go  after all, I  originally asked him
what he thought. He got  interested in  doing  this, it would not be very
fair not to give  a fair go. If it works   and I have no reason to doubt
that it  won't then why not? For others  it  simply gives another  option
for a throttle control system. I'm  already  completely  reliant on all
sorts of other electronics and  electrical  systems  for flying using
an RX-8 Engine, for instance  Tracy's  EC3, Tracy's EM3,  fuel pumps,
trim system etc.

Apart   from anything else it is just  plain fun to see if it can or  will
work  without spending too much time or  money on it, we've  only spent  a
couple hours on it so far, I suspect that  it will  go to a  working
prototype with only a very few more hours which  is  pretty  good, it
would more than likely have taken me at  least several hours   working out
how and where to run the  push/pull cables as well as in   fabrication time
of a number or  brackets and the like and to make sure  that  it would not
get  damaged or bind going to the engine keep water  out of the  cables
etc.

Regards David

--

Greetings  David.

I am  also of the rear engine persuasion (aero canard SX). The  length  of
the
cable is somewhat immaterial. It's been used in boats  (much  longer run)
for
years, as well as virtually all twins, each of   which has  longer and more
tortuous runs.

The tandem  throttle  arrangement does create some problems, but not
unsolvable  with cables.  Merely run one cable from the front lever to  a
fixture  at the aft  throttle control which connects this front  cable to
the
rear cable (kind  of like a union with a perpendicular  bolt to engage the
aft throttle lever.  This fixture (union) can be as  simple as the
arrangement
used in the  locking mechanism of the  canopy, or as sophisticated as  you
like.

With this  arrangement, the forward throttle is directly  connected to  the
engine, albeit through the fixture.

The cables can  be  routed any way you please.
Good cables are lubricated, can be bent  and  give a sturdy attachment.

This gives tactile feedback with  the  throttle. Even the Airbus which is a
FBW craft syntheses feedback  to the  pilot.  Direct  connection, indeed,
tells you  throttle plate  position, binding and a myriad  of things  which
you
can't get with  wire. Perhaps some feedback  information  forewarning  of
some
possible impending  malfunction (a bad place to have   one)

If You use TK's EC2  or 3, you have redundancy in spark, in go  juice, but
absolutely no  redundancy in throttle position nor feedback  information,
or
even  function.

Please don't get me wrong, I  really  want to use the fly-by wire but I need
more info before I trust my   Glutei maximi to it

Rich


--

Hi, Rich - I'll try  to  keep this shorter this time.

Agree the cable length does not  really  matter. Tandem Throttle link-up
was always going to be cable.  The Throttle  levers are designed for it,
so I'll use it. Good Cables  are the only ones  to use :), Cables can
routed anywhere within reason  but, wires are much  more flexible, the
limitations for cables are  bend radius which forces some  space & minimum
distance limits.  Wires with the Throttle body have  basically none.
Tactile feedback in  this really comes from friction which  is built-in to
the throttle  levers I'm using already. There are thousands  or millions of
these  style or throttle systems in use today all around the  world. If  the
throttle body was already designed for a cable, I simply  would  use it
without a second thought.

Tracy Crook   (http://www.rotaryaviation.com) is the designer and seller
of the EC3  &  EM3.

T.K. is a friend of mine that used to work up until  very recently  in R&D
in
the Auto industry designing and  developing this sort of  stuff, He want to
do this now, I have have to  give the fair  go.

Regards David


--Hi David,

I  mistyped.

I meant Tracy Crook (TC) but used K instead of C. I  agree with the
limitations of the radius of the cables. When I referred to  tactile, I was
referring not specifically to the resistance of the lever,  (as you
correctly
stated a product of the friction), but the mechanical  awareness of the
connection to the butterfly and it's actual position. With  FBW, it is
possible  to
think that you have full open throttle  (because of full throttle position)
and actually have the butterfly (or  whatever you use to shut down the
airflow)  closed giving you one more  totally unknown in the event of an
engine
problem.  Unknowns eat up  valuable time when attempting to troubleshoot an
engine problem  at  low altitude.

Case in point:

As I was approaching Peoria, IL  about 4 years ago, in my dragonfly, less
than 1k AGL, my engine did not  respond to advancing throttle. The linkage
that I  used was a  cable(high quality) pulling against spring tension. The
spring opened   the throttle. the cable closed it. Seemed like a good idea
at the
time. a  cable  snap would yield a fully open throttle and a pull only
cable
could be bent in a  smaller radius.

Descending for my  approach to KPIA, upon leveling off, I advanced the
throttle, The lever  felt normal, but the engine continued to idle. I spent
precious time trying  to trouble shoot and correct the problem. The episode
resulted in the  plane's destruction and my survival landing on the only
area,
way too  small for a normal landing with a 40K tailwind with berms and
farming  implements at what would be the end of my rollout. Not a good
scene.  The
only other place was into the wind on a freshly plowed wet field (did  I
mention  it was rainy?)

Post accident (incident)  investigation revealed nothing wrong with the
engine of the linkage.  However, Post Post inspection (after dragging the
corpus
home)  revealed that a heat shield may have distorted with heat jamming the
throttle closed. (Idle) and when I added throttle, the relaxing cable  had
no  effect since the spring tension was now counteracted by  friction to the
heat  shield. I had no idea of this since from  throttle position and
friction all  appeared normal. After "arrival"  and cooling down, the heat
shield
returned to  it's normal position  and the throttle worked correctly.

This is not to justify the design  error but to say that a solid throttle
connection would have notified me  immediately that the throttle was jammed,
or  possibly given me the  ability to muscle open the throttle yielding a
totally  different  result. This event happened after 100 H TT.

Had I been aware that the  throttle was not opening, or going to open,
perhaps I would not have wasted  the precious moments trying to
troubleshoot and
would have been able to put  it down in a more hospitable place I had
passed.

When you have an  engine failure at low altitude, although time flows like
molasses, every  second is critical.

Rich

An electronic throttle needs a computer  to control it.
What happens if the computer goes insane?  :)
http://www.fear-of-flying.us/index.php?p=1_11_The-Robot-Plane
It can  kill you long before you can do anything about it.

Current airplanes  have carburetors, magnetos and throttle cables for
very good  reasons.

Paul Lamar


Paul,

Just to show that I can argue on both sides of the issue:

Current aircraft engines are now going to fuel injection Large  aircraft
engines have all gone to fuel injection.

Electronic FI and ignition will be commonplace when certifying new engines
becomes, once again, financially viable.

50 or more year old technology will ultimately yield.

Many of the things in certified aircraft are there because that's the way
they were certified in a different era and the cost to re certify, at this
point  in time is prohibitive.

Will pistons ever disappear in favor of the "rotating wobble" --  perhaps.

At this point, I still like a solid throttle connection.

Rich

Are you picking nits? :) Should I have said >>MECHANICAL<< fuel injection? :)

Which aircraft engines are going to EFI?  MECHANICAL fuel injection
has been available for years.

Put this string in google and see what you get "Electronic fuel injection
on aircraft engines". Nada :)

BTW Wankel rotary engines do not "wobble"!!!!

http://www.rotaryeng.net/how-wank-works.html

"Many engineers and mechanics that should know better still think the rotor
translates, reciprocates or wobbles in the rotor housing. Nothing could be
further from the truth."

Paul Lamar