Should I consider a Hirth 2706?
la...@larryville.com
I had a nice chat with the Hirth rep at Sun 'n Fun (wish I had gotten
his name), and came away from it very impressed with Hirth. I hear
that Hirth has had lots of problems in the past, but from what the rep
told me and from what I read in their rather convincing brochure, I
can't help but wonder if they have turned things around to the point
where it could be a good investment for me.
I'm building a TEAM Tandem AirBike with the intent of using it lightly
as a hang glider tug (see http://www.larryville.com/dcd/tandem ). The
Tandem was designed for the 503, but I'm looking for something in the
65-80hp range. The 65hp Hirth 2706 appears to the PERFECT engine for
this airframe/power need.
I've heard enough stories about seizures from Hirth's recent PAST to
keep me away from the older engines. What I'm really looking for is
people who can help me evaluate where Hirth is right now in terms of
reliability and other important aspects I should consider before
making a major investment like this.
Here are two aspects from the new Hirth brochures which lead me to ask
if the Hirth is a good engine now -- New Alloy Combinations and Fuel
Injection.
New Alloy Combinations:
"Today at Gobler-Hirth we have new material combinations which
eliminate (piston seizure). The light metal piston is made of a
special alloy that expands slower under thermal load than the light
metal cylinder walls. An engine seizure even under extreme conditions
is nearly impossible. Beyond that, Gobler-Hirth uses a new alloy for
the cylinder heads which allows the engines to run for long durations
at maximum power."
Fuel Injection:
"Today at Gobler-Hirth we developed a programmable fuel injection for
our engines with (which) the following operating parameters will be
established: Air temperature, air pressure, engine temperature,
exhaust temperature, RPM and throttle postion. With the recording of
all those measurements it will be feasible to get the exact fuel-air
mix for each engine, only what the engine really needs. As much fuel
as necessary and as (little) as possible. Up to 40% less than in the
past (with carburetors).
With this procedure, it's impossible to run the engine too rich or to
overheat it. Temperature compensation and altitude compensation is
completely automatic. It's impossible to ice-up the carburetor."
This all sounds great to me. Advertising hype, or is there significant
truth to this?
Thank you for any light you can shed,
Doug
ps: I heard that a plane doing an evening aerobatic/fireworks routine
at Sun 'n Fun was downed due to a Hirth seizure. Anyone know if this
is true, and if it was a new-generation Hirth?
David Ervin
> Hi everyone,
>
> I had a nice chat with the Hirth rep at Sun 'n Fun (wish I had gotten
> his name), and came away from it very impressed with Hirth. I hear
> that Hirth has had lots of problems in the past, but from what the rep
> told me and from what I read in their rather convincing brochure, I
> can't help but wonder if they have turned things around to the point
> where it could be a good investment for me.
> is true, and if it was a new-generation Hirth?
<snipped>
This dealer/distributor has had some experience with the new engines I've
heard. They did have an engine out, but I think it was due to a
broken/loose wire to the fuel injection computer.
http://www.adventultralight.com/
Nice little flight park also. Located in San Antonio, Texas (or close to
it). I am interested in this engine setup also.
David
Alan Staats
<dav...@lakewood.sps.mot.com> wrote:
>la...@larryville.com wrote:
>
>> Hi everyone,
>>
>> I had a nice chat with the Hirth rep at Sun 'n Fun (wish I had gotten
>> his name), and came away from it very impressed with Hirth. I hear
>> that Hirth has had lots of problems in the past, but from what the rep
>> told me and from what I read in their rather convincing brochure, I
>> can't help but wonder if they have turned things around to the point
>> where it could be a good investment for me.
>> is true, and if it was a new-generation Hirth?
>
talk to chuck sluzarczik (sp?) at CGS Aviation. from what i heard at
snf the hirths are still somewhat unreliable.
Alan Staats
www.flightleveldesign.com
Geoff Thistlethwaite
(Hi Alan :)
Geoff "wish I had fuel injection on my R503/Firestar" Thistlethwaite
Scrappman
he won't B.S. you either.
Scrappman
Juan Jimenez (TeamB)
the Rotax 582. The fuel injection and lack of requirement for a radiator
and water cooling are certainly two pluses. You might also want to email
sa...@bd-micro.com, they've recently become a Hirth master dealer after
exploring most of the other options.
Juan
la...@larryville.com wrote:
>
> Hi everyone,
>
> I had a nice chat with the Hirth rep at Sun 'n Fun (wish I had gotten
> his name), and came away from it very impressed with Hirth. I hear
> that Hirth has had lots of problems in the past, but from what the rep
> told me and from what I read in their rather convincing brochure, I
> can't help but wonder if they have turned things around to the point
> where it could be a good investment for me.
>
Mark Hickey
>New Alloy Combinations:
>"Today at Gobler-Hirth we have new material combinations which
>eliminate (piston seizure). The light metal piston is made of a
>special alloy that expands slower under thermal load than the light
>metal cylinder walls. An engine seizure even under extreme conditions
>is nearly impossible.
I dunno, but it sure seems to me like this same "feature" would be
likely to cause a shock cooling seizure (i.e. running the engine hard
and hot, and chopping the power back, allowing the "light metal
cylinder walls" to contract quicker than the "special alloy that
expands slower under thermal load".
Mark Hickey
Kevin O'Brien
wrote:
> It's impossible to ice-up the carburetor."
>
>
> This all sounds great to me. Advertising hype, or is there significant
> truth to this?
This one line is definitely true. Ice forms in carbs because the venturi
drops the temp of the air and the water vapour solidifies out. Fi
engines dispense with venturis. So this will eliminate that one cause of
stoppages/power reductions definitively.
Whether it introduces new problems I can't say. It may introduce new
complications that are worse than carb icing (which is scarcely a
leading cause of UL power loss, eh).
Whether they have beaten the sticky-piston type stoppages, I also can't
say. They say they have.
Good luck with your AirBike.
cheers
-=K=-
Lawrence and Carey Dorn
will answer all questions and is very helpful. I have 12 hrs on my new
engine.
Lawrence
Silverdale, Wa
<la...@larryville.com> wrote in message
news:391AD6E9...@larryville.com...
> Hi everyone,
>
> I had a nice chat with the Hirth rep at Sun 'n Fun (wish I had gotten
> his name), and came away from it very impressed with Hirth. I hear
> that Hirth has had lots of problems in the past, but from what the rep
> told me and from what I read in their rather convincing brochure, I
> can't help but wonder if they have turned things around to the point
> where it could be a good investment for me.
>
> I'm building a TEAM Tandem AirBike with the intent of using it lightly
> as a hang glider tug (see http://www.larryville.com/dcd/tandem ). The
> Tandem was designed for the 503, but I'm looking for something in the
> 65-80hp range. The 65hp Hirth 2706 appears to the PERFECT engine for
> this airframe/power need.
>
> I've heard enough stories about seizures from Hirth's recent PAST to
> keep me away from the older engines. What I'm really looking for is
> people who can help me evaluate where Hirth is right now in terms of
> reliability and other important aspects I should consider before
> making a major investment like this.
>
> Here are two aspects from the new Hirth brochures which lead me to ask
> if the Hirth is a good engine now -- New Alloy Combinations and Fuel
> Injection.
>
> New Alloy Combinations:
> "Today at Gobler-Hirth we have new material combinations which
> eliminate (piston seizure). The light metal piston is made of a
> special alloy that expands slower under thermal load than the light
> metal cylinder walls. An engine seizure even under extreme conditions
> is nearly impossible. Beyond that, Gobler-Hirth uses a new alloy for
> the cylinder heads which allows the engines to run for long durations
> at maximum power."
>
> Fuel Injection:
> "Today at Gobler-Hirth we developed a programmable fuel injection for
> our engines with (which) the following operating parameters will be
> established: Air temperature, air pressure, engine temperature,
> exhaust temperature, RPM and throttle postion. With the recording of
> all those measurements it will be feasible to get the exact fuel-air
> mix for each engine, only what the engine really needs. As much fuel
> as necessary and as (little) as possible. Up to 40% less than in the
> past (with carburetors).
>
> With this procedure, it's impossible to run the engine too rich or to
> overheat it. Temperature compensation and altitude compensation is
> completely automatic. It's impossible to ice-up the carburetor."
>
>
> This all sounds great to me. Advertising hype, or is there significant
> truth to this?
>
chute
all had crank bearing failures. all were on new ppcs.
Mark Hickey wrote in message <391bfa57...@News.CIS.DFN.DE>...
>la...@larryville.com wrote:
>
>>New Alloy Combinations:
>>"Today at Gobler-Hirth we have new material combinations which
>>eliminate (piston seizure). The light metal piston is made of a
>>special alloy that expands slower under thermal load than the light
>>metal cylinder walls. An engine seizure even under extreme conditions
>>is nearly impossible.
>
>I dunno, but it sure seems to me like this same "feature" would be
>likely to cause a shock cooling seizure (i.e. running the engine hard
>and hot, and chopping the power back, allowing the "light metal
>cylinder walls" to contract quicker than the "special alloy that
>expands slower under thermal load".
>
>Mark Hickey
Juan Jimenez (TeamB)
engines manufactured? The design of the engine has been upgraded quite a
bit.
pat mitchel
wouldn't it? A fi only injects fuel into the intake( or
combustion chamber). You still need to get air to the cylinder.
And that air would go through a velocity (and pressure) change.
Is it the presence of the fuel in the incoming mixture that
would cause the ice to form. I was under the impression that the
water in air was the reason for the ice to form. Regards Pat
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Charles K. Scott
pat mitchel <patm317...@hotmail.com.invalid> writes:
> Kevin; A question about fi. A fi would still have a venturi,
> wouldn't it? A fi only injects fuel into the intake( or
> combustion chamber). You still need to get air to the cylinder.
> And that air would go through a velocity (and pressure) change.
> Is it the presence of the fuel in the incoming mixture that
> would cause the ice to form. I was under the impression that the
> water in air was the reason for the ice to form. Regards Pat
In a carburator there has to be a venturi in order to mix the fuel with
the air. Without the venture there is no way to draw the fuel from the
float chamber. It's the "free" part about carburation, that physical
property that allows it to operate without electricity or artificial
pressure. Venturi's cause a pressure drop which sucks the fuel into
the passing high velocity air. It's this pressure drop that can also
cause ambient humidity in the air to condense out and freeze to things
in the carburator, usually the ventury itself.
Fuel injection, if it's the port type, doesn't usually have a venturi,
there's no need for it. All the intake manifold has to do is conduct
air to the cylinder in equal amounts. Almost any kind of manifold will
do and that's why it's not a good idea to bolt a carburator on top of a
fuel injection type manifold, unless it is a single point type
injector. Multi point fuel injection manifolds are designed to flow
air, not air and fuel. Fuel slings out against sharp corners reducing
the amount of fuel that ends up at the intake valve for that cylinder.
Intake manifolds for carburators have to be very carefully designed to
limit this slinging. Single point injectors are kind-of like
sophisticated carburators and they still need some sort of venturi in
order to atomize the fuel droplets being injected into the airstream.
Corky Scott
Badwater Bill
Larry:
Get ahold of Chuck S. at CGS Hawk. He's sold a ton of them on his
airplanes. I don't know why he uses the Hirth over the Rotax but I'm
sure there's a reason. When you find out, let us all know.
BWB
pat mitchel
build up. Regards Pat
bart simpson
Hey Badwater,
I just got the software off Ray after my computer got fragged by the
iloveyou thing. Let me know if this is working. I'm still recovering
from Scud n Mudd 2000. Take it easy.
Bart Simpson
highflyer
>
> Kevin; A question about fi. A fi would still have a venturi,
> wouldn't it? A fi only injects fuel into the intake( or
> combustion chamber). You still need to get air to the cylinder.
> And that air would go through a velocity (and pressure) change.
> Is it the presence of the fuel in the incoming mixture that
> would cause the ice to form. I was under the impression that the
> water in air was the reason for the ice to form. Regards Pat
>
With a carbureted engine most of the temperature drop in the intake
system that causes ice to form is a result of the vaporization of the
fuel. With a carburetor this vaporization takes place in a relatively
cool portion of the intake system, usually right behind the throttle
plate.
With fuel injection you still do have a throttle plate. However, the
fuel
is sprayed into the intake stream right above the intake valve where
the higher temperatures near the cylinder head can readily provide
sufficient heat for the vaporization to take place without dangerously
lowering the intake temperature allowing freezing. It is still
possible with lower throttle settings and cool humid air to get some
icing behind the throttle plate, but it is far less common because
the fuel vaporization is taking place elsewhere.
--
HighFlyer
Highflight Aviation Services