Author: "jimcinlexky" <JimC@...> Time: Mon Aug 9, 2004 3:36 pm PDT Link
Dave,
I think you are right on with your assessment of the two most likely
alternative engine options.
What I think I am goin to do is to make the modifications to the
filler on the tanks (Larger filler openings, extra vent) and then
watch to see what happens over the next year. At least allow for
the option of burning jet-A or diesel.
Jim C
(#192)
--- In RV10@yahoogroups.com, "Dave Hertner" <effectus@r...> wrote:
> Bob,
>
> Sorry that I missed you at Oshkosh. I was there with bells on.
I took some serious time to look over the DeltaHawk and I liked what
I saw. What I had some trouble with was the horsepower. I know that
I have been doing a lot of talking about the engine. The concept and
execution of the engine is eloquent and it is poised to fill the
need out there for an engine in the under 200hp class with a
vengeance. I wasn't totally convinced that it is the replacement for
the IO-540 though.
>
> My convictions have been challenged globally except for the
fact that I know that the engine going into my airplane will be
burning diesel for at least 2/3 of the year. The economics speak
loudly. I pay about US$ 3.60 per gal here for 100LL. I can get
diesel for US$ 1.74 Irregardless of the engine I choose for my RV-10
I have to burn Diesel in it. The feeling that I got from the guys at
the booth was that the DeltaHawk was a JetA engine. Diesel was not
discussed for any length of time.
>
> This brings me to today. I spent a great deal of time at the
Innodyne booth as well and as you stated Chuck has done an excellent
job on the engines. Yes they will burn some more fuel but they
aren't going to burn twice the fuel and they willingly say that the
engine is designed to burn Diesel. They are also rated to the 255hp
that I need for this airplane. With the weight reduction and the
reduction in flat plate area on the nose, I think this will be a
230mph airplane. That extra range will offset a good portion of the
increased fuel burn.
>
> I am currently building my elevators and I don't anticipate
having to make the engine decision for a couple of years yet. The
decision I have to make soon is the type of fuel because of the
modifications I have to make to the vent system and the fuel filler
neck size. I have a couple of Oshkoshs to attend before signing on
the dotted line.
> ----- Original Message -----
> From: bob@d...
> To: rv10@yahoogroups.com
> Sent: Saturday, August 07, 2004 8:59 PM
> Subject: Re: [RV10] Re: Innodyne
> Dave,
> Did you visit the DH booth? I was hoping to meet ya at OSH
after all the
> communications :-)
>
> Chuck Nearhoof spent some time with us talking engines. I met
him several
> years ago at SNF. He's done a nice job on his turbines. Fuel
burn will be a
> tough challenge though, as it is with all turbines. Just the
nature of the
> beast. Beautiful installation in the RV6.
>
> Bob Shippee
> ______________________________________
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Author: "bob.kaufmann" <bob.kaufmann@...> Time: Tue Aug 10, 2004 1:39 am PDT Link
My 2 cents on the engine question. I have talked with Chuck at Innodyne and
with DeltaHawk and am torn on the choice also. I worry, like everyone else
on fuel flow and on horsepower. The Innodyne does not have verifiable
performance numbers yet, I would hope that they would have by now but not.
Deltahawk is low on power at sea level, but with the turbo and supercharger,
that will get made up in altitude fast. Deltahawk also will be coming out
with an Intercooler which should add 7 to 10% to the rated horsepower. That
will bring it to 215 to 225 hp. Which way to go. No idea!!! The big
thing is that you can put the bigger filler caps in and the venting in and
it will not hurt you, just won't look as cool. As the engine products prove
themselves you will have all the choices available to you.
I personally want either a turbine or a diesel, for the cost of fuel and for
the availability. There is not a whole lot of difference between jet a,
kerosene, diesel, jet 8 or jp4. All will work in either engine.
Bob K
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Author: "eric_panning" <eric_panning@...> Time: Wed Aug 11, 2004 1:00 am PDT Link
My 1.5 cents... Between these choices, Deltahawk is the better one.
As someone else pointed out, few airports are SL and at standard
temp. Turbo-normalized diesel offers flexibility and performance at
a range of altitudes. I was worried about diesel availability but if
you look on www.airnav.com for fuel locations you will find plenty
with 24 hr no-surcharge Jet-A.
Deltahawk could release more data - but at least they have posted
dyno runs, etc. Innodyn has not to my knowledge. Observations of RV-
4 climb performance tend to confirm my opinion that no news is bad
news. I've seen their slick videos on the www.innodyn.com website but
could not find any data. I think the old ATP site actually had more
data on it...
Another consideration for both engines is CoG. The innodyn might be
too light forcing you to extend the cowl. I'm not sure if they
extended the cowl in the RV-6 but the delta in engine weight between
and IO-540 and the Innodyn is > 200 lbs. Sure, you can move
batteries, etc. - but if you have to extend the cowl you are really
adding the experimental to experimental aviation. For example, how
will the spin characteristics change? How far would you be prepared
to go in flight testing to find out? How much will it cost you for a
new cowl? Will MT or ? make a prop that can do zero pitch for starts,
yet have the pitch range for cruise? Electric or hydra. and is
electric fast enough? How much?
Innodyn may have made real advances in controls for small turbines,
but it does not change the fact that turbines are inherently less
efficient than gasoline or diesel. Typical is ~ 0.6 BSFC for
turboprop vs 0.42 for lycoming vs 0.39 for Diesel. Estimated fuel
burn for 200 HP for turboprop would be 120 lbs/hr or 17 gal/hr. 200
HP lycoming = 84 lbs/hr or 14 gallons. 200 HP diesel = 76 lbs/hr or
11 gallons. For the turboshaft, you are looking at 3 hr range. For
the diesel, ~ 5 hrs at the same speed cruise speed. Perhaps you
could find a way to expand the fuel tanks (I've looked at that
section in the manual - no thanks!). What if you converted that 200
lb weight savings into Jet-A? It would buy you ~ 30 gallons or 1.5
hrs extra cruise. Still short of the diesel with standard tanks....
If fuel cost is a concern, Diesel will always come out ahead.
I am starting on the wing kit, but will delay the fuel tanks until
the engine choice has been made. The engine starts in the tanks.
Don't build them until you have decided as the optimal solution will
be different for each option.
Random points: Most of Diesel advantage in economy is diesel is 7 lbs
vs 6 lbs per gallon. More Hydrocarbons to burn... Also, peak
cylinder temps are an indication of engine efficency. Diesel has a
higher peak temp and lower average temp as the energy is recovered
more efficiently. Gasoline is not far behind. Peak temp lower,
average higher. Turbines are limited by exhaust temp limits. One
advantage of high alt operations is delta T is greater. You can
generate high delta temps without exceeding limits at altitude due to
cooler intake air (and a number of other things). Max temp is lower
than diesel or gas peak temps. Materials for really high temp ops
are exotic....
Eric
--- In RV10@yahoogroups.com, "bob.kaufmann" <bob.kaufmann@c...> wrote:
> My 2 cents on the engine question. I have talked with Chuck at
Innodyne and
> with DeltaHawk and am torn on the choice also. I worry, like
everyone else
> on fuel flow and on horsepower. The Innodyne does not have
verifiable
> performance numbers yet, I would hope that they would have by now
but not.
> Deltahawk is low on power at sea level, but with the turbo and
supercharger,
> that will get made up in altitude fast. Deltahawk also will be
coming out
> with an Intercooler which should add 7 to 10% to the rated
horsepower. That
> will bring it to 215 to 225 hp. Which way to go. No idea!!!
The big
> thing is that you can put the bigger filler caps in and the venting
in and
> it will not hurt you, just won't look as cool. As the engine
products prove
> themselves you will have all the choices available to you.
> I personally want either a turbine or a diesel, for the cost of
fuel and for
> the availability. There is not a whole lot of difference between
jet a,
> kerosene, diesel, jet 8 or jp4. All will work in either engine.
> Bob K
> _____
> [Non-text portions of this message have been removed]
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Author: "vanlle2000" <vanlle2000@...> Time: Wed Aug 11, 2004 12:33 pm PDT Link
I enjoyed this post because it made so much sense and didn't fall
into the "newer must be better" trap. Learned a few things, too.
A couple of comments:
I looked at the Innodyn briefly at Osh and it would be my last choice
of engines for an RV-10. If the fuel economy was really as good as a
piston engine, the tent would have been full of Pratt and Whitney or
GE guys trying to learn how they'd done it. Just the size of the
projecting exhaust pipes in that RV-6 probably increased the flat
plate area of airplane 20%.
I just cant see how a turbine is going to be an advantage on an
airplane that is designed to fly in the lower quarter of the
atmosphere and has just 60 gallons of capacity. This is where the
piston engine does it's best work and no turbine yet has matched it
for cost or economy or even simplicity...yeah I know the turbine
engine is simpler, but there's the precision it needs to make it
work, and the gearbox and the complex prop controls and fuel metering
systems....none of which I would feel comfortable working on in my
home hangar.
As far as diesels, Eric is exactly right: if we bought fuel by the
btu content or weight, instead of volume, the price advantage would
dissappear. Given that diesel fuel is denser, we get more miles per
dollar when we buy by volume. The engines and fuels are both
heavier, so the useful load goes down, even if the range goes up.
Flew 4500 miles to Osh and back this year and only landed at one
airport that had Jet A. Only the big airports around my area have
it, and I noticed the last time I was into one that JetA was
3.05/gallon, while 100LL was 2.90
--- In RV10@yahoogroups.com, "eric_panning" <eric_panning@y...> wrote:
> My 1.5 cents... Between these choices, Deltahawk is the better
one.
> As someone else pointed out, few airports are SL and at standard
> temp. Turbo-normalized diesel offers flexibility and performance
at
> a range of altitudes. I was worried about diesel availability but
if
> you look on www.airnav.com for fuel locations you will find plenty
> with 24 hr no-surcharge Jet-A.
>
> Deltahawk could release more data - but at least they have posted
> dyno runs, etc. Innodyn has not to my knowledge. Observations of
RV-
> 4 climb performance tend to confirm my opinion that no news is bad
> news. I've seen their slick videos on the www.innodyn.com website
but
> could not find any data. I think the old ATP site actually had
more
> data on it...
>
> Another consideration for both engines is CoG. The innodyn might
be
> too light forcing you to extend the cowl. I'm not sure if they
> extended the cowl in the RV-6 but the delta in engine weight
between
> and IO-540 and the Innodyn is > 200 lbs. Sure, you can move
> batteries, etc. - but if you have to extend the cowl you are really
> adding the experimental to experimental aviation. For example, how
> will the spin characteristics change? How far would you be prepared
> to go in flight testing to find out? How much will it cost you for
a
> new cowl? Will MT or ? make a prop that can do zero pitch for
starts,
> yet have the pitch range for cruise? Electric or hydra. and is
> electric fast enough? How much?
>
> Innodyn may have made real advances in controls for small turbines,
> but it does not change the fact that turbines are inherently less
> efficient than gasoline or diesel. Typical is ~ 0.6 BSFC for
> turboprop vs 0.42 for lycoming vs 0.39 for Diesel. Estimated fuel
> burn for 200 HP for turboprop would be 120 lbs/hr or 17 gal/hr. 200
> HP lycoming = 84 lbs/hr or 14 gallons. 200 HP diesel = 76 lbs/hr
or
> 11 gallons. For the turboshaft, you are looking at 3 hr range.
For
> the diesel, ~ 5 hrs at the same speed cruise speed. Perhaps you
> could find a way to expand the fuel tanks (I've looked at that
> section in the manual - no thanks!). What if you converted that
200
> lb weight savings into Jet-A? It would buy you ~ 30 gallons or 1.5
> hrs extra cruise. Still short of the diesel with standard
tanks....
> If fuel cost is a concern, Diesel will always come out ahead.
>
> I am starting on the wing kit, but will delay the fuel tanks until
> the engine choice has been made. The engine starts in the tanks.
> Don't build them until you have decided as the optimal solution
will
> be different for each option.
>
> Random points: Most of Diesel advantage in economy is diesel is 7
lbs
> vs 6 lbs per gallon. More Hydrocarbons to burn... Also, peak
> cylinder temps are an indication of engine efficency. Diesel has a
> higher peak temp and lower average temp as the energy is recovered
> more efficiently. Gasoline is not far behind. Peak temp lower,
> average higher. Turbines are limited by exhaust temp limits. One
> advantage of high alt operations is delta T is greater. You can
> generate high delta temps without exceeding limits at altitude due
to
> cooler intake air (and a number of other things). Max temp is
lower
> than diesel or gas peak temps. Materials for really high temp ops
> are exotic....
>
> Eric
>
> --- In RV10@yahoogroups.com, "bob.kaufmann" <bob.kaufmann@c...>
wrote:
> > My 2 cents on the engine question. I have talked with Chuck at
> Innodyne and
> > with DeltaHawk and am torn on the choice also. I worry, like
> everyone else
> > on fuel flow and on horsepower. The Innodyne does not have
> verifiable
> > performance numbers yet, I would hope that they would have by now
> but not.
> > Deltahawk is low on power at sea level, but with the turbo and
> supercharger,
> > that will get made up in altitude fast. Deltahawk also will be
> coming out
> > with an Intercooler which should add 7 to 10% to the rated
> horsepower. That
> > will bring it to 215 to 225 hp. Which way to go. No idea!!!
> The big
> > thing is that you can put the bigger filler caps in and the
venting
> in and
> > it will not hurt you, just won't look as cool. As the engine
> products prove
> > themselves you will have all the choices available to you.
> > I personally want either a turbine or a diesel, for the cost of
> fuel and for
> > the availability. There is not a whole lot of difference between
> jet a,
> > kerosene, diesel, jet 8 or jp4. All will work in either engine.
> > Bob K
> > _____
> > [Non-text portions of this message have been removed]
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Author: shiprv8@... Time: Wed Aug 11, 2004 7:11 pm PDT Link
In a message dated 8/11/04 3:34:50 PM Eastern Daylight Time,
vanlle2000@yahoo.com writes:
As far as diesels, Eric is exactly right: if we bought fuel by the
btu content or weight, instead of volume, the price advantage would
dissappear. Given that diesel fuel is denser, we get more miles per
dollar when we buy by volume. The engines and fuels are both
heavier, so the useful load goes down, even if the range goes up.
This may be confusing, so bear with me. The above statement is a common
perception but it's not completely accurate (no offense!). Even for the same BTU
content, a diesel engine is more efficient than a gasoline engine by around
20%.
Here's the paradox: diesel has only 10% more energy per gallon yet gets 30%
more mileage per gallon than gas engine for same power.
why? combustion is far more efficient in diesel engines. Higher combustion
temps and leaner mixtures than gas engines make for higher efficiency (HP per
BTU).
If a diesel could run on gasoline, it would get better mileage at the same
power setting than an equivalent HP gasoline engine.
actually, avgas and jet-A have virtually the same btu per POUND (avgas is
actually slightly higher than jet-A in energy content per pound). But jet fuel
is about 10% denser than avgas, so Jet-A has more btu per GALLON than avgas.
Jet-A has 10% more energy per gallon than 100LL:
a gallon of 100LL weighs 6.0 lb and has 112,800 BTU (18,800 BTU/lb)
a gallon of Jet-A weighs 6.7 lbs and has 125,400 BTU (18,720 BTU/lb)
if we filled 2 planes with the same BTU, we'd end up with different volumes
(gallons) for same energy content.
even so, for the same BTU, a diesel would out-fly the gasoline engine by
around 20% b/c a diesel requires appx 20% less energy mass per hp than a gasoline
engine.
This is where BSFC comes in. BSFC represents the efficiency of converting a
pound of fuel into HP. BSFC = lb/hp/hr. Since 100LL and jet/diesel have the
SAME btu per POUND, a gas engine running at .45 BSFC (real-world) is 20% less
efficient than a diesel running at .38 BSFC (real-world).
add in the 10% density factor per gallon and you get the typical 30% increase
in range for diesels over gasoline engines for the same fuel volume, i.e.
whatever your tanks will hold.
clear as mud, right? :-) Quiz on Monday.
ps: a turbine is less efficient than recip engines due to lower temp limits
AND lower mechanical efficiency in converting energy into work. Combustion
temps in a diesel are typically around 4500*F but only for a fraction of a
second....turbines are continuous-burn...they will melt at these temps, thus must
run at lower temps i.e. lower efficiency.
Pistons also provide greater mechanical leverage than fan disks for the same
pressures. Even if a turbine could survive at 4500*F (think about EGT at
4,500!!) it would still be less efficient than any piston engine for the same HP.
Ship
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Author: "bob.kaufmann" <bob.kaufmann@...> Time: Thu Aug 12, 2004 3:36 am PDT Link
OK I'm sold, diesel it is and that makes in Deltahawk. The other diesels
coming on the market are out of my dollar range. Guess tomorrow is soon
enough to send in my money.
Bob K
_____
From: shiprv8@aol.com [mailto:shiprv8@aol.com]
Sent: Wednesday, August 11, 2004 4:30 PM
To: RV10@yahoogroups.com
Subject: Re: [RV10] Re: Innodyne & Delta-Hawk
* In a message dated 8/11/04 3:34:50 PM Eastern Daylight Time,
vanlle2000@yahoo.com writes:
As far as diesels, Eric is exactly right: if we bought fuel by the
btu content or weight, instead of volume, the price advantage would
dissappear. Given that diesel fuel is denser, we get more miles per
dollar when we buy by volume. The engines and fuels are both
heavier, so the useful load goes down, even if the range goes up.
.
[Non-text portions of this message have been removed]
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