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Deltahawk at Sun N Fun ? (2013)

How about this year? SR20 anyone?

Check the "what's new" on their site.

www.deltahawkengines.com

Thanks for your patience. If it was easy.... everyone would do it.

Kind and respectful regards to all Van's drivers.

JP Brooks
777 pilot/N211JP
co-founder, DeltaHawk Engines, inc.
 
Welcome to VAF!

JP, welcome to VAF:D

Tell us about the DH Velocity please. Hours, flight characteristics of the engine setup, etc.

Good to have you aboard.
 
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Glad to finally see a SR-2X materialize. Purely based on advertised numbers, I would consider building a DH powered plane. I hope the cirrus works out and leads to many a firewall forward kit. Any pics or vids of the cirrus flying behind it? Close to predicted/advertised specs?
 
SR20

Doug and Team is working diligently 28 hours/day to get the data. We believe it will surpass 30% better fuel flow with Jet-A and will let the numbers speak for themselves when they are archived.

We like to call Doug the "Father" of the engine since 95%+ of the V4/A4 engine is his design and thoughts. Our CEO, Dennis Webb, is not only a talented business person but also an engineer. He has also put so much into this project.

Our press release is on our front page of our web site. I know the data coming soon will be enjoyable, especially for Dennis, Doug, and myself. We been at this for some time now and deserve a bit of press for the years that have aged us all. That's all the "talk" I can say for now. It will be substantiated by "The Walk". You Guys (and Gals) need proof/numbers as any pilot would expect so,.... the more we "do" and the less we "talk" will capture press.

A side note: I did visit with Mr. V. back in 2003 and he was gracious to receive me, but made sure I saw the big Wall of Lycomings he ships with kits. Maybe in the future he'll invite me back to see the "Wall" of DeltaHawk engines where Lycomings used to glare in my face. And.... maybe the first RV with a DH engine will elicit an invite back. I live in Camas, WA, bout 50 miles north of the Van's factory. I would write more but I need to commute to ORD to head to Beijing tonight. (777 pilot as well as Velocity. Yes,... we are hoping to re-engine a 777... wouldn't want to under-challenge ourselves again, right)

Safe flying to all and keep those gorgeous birds coming. They will need new engines when the numbers tell you... "it's worth it".

JP (disclaimer: I type fast, plz forgive the typos)
 
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What I noticed was...

Cowl looks like it is an "A" vs "V" configuration.
 
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Very Cool! Deltahawk engines had my attention years ago when I first saw it at oshkosh. Would be a great option for a RV.

I didn't see any details on the website about a "A" configuration. Is there more information on this?
 
Oshkosh

We will have the Cirrus at OSH...AND,..... Possibly have an RV!
Don't know 'bout you... But, this rolls my sox up and down.

Hope to meet you all some day if you will allow me to drool all over your RVs.
JP
 
A4 config

Yes, an A4 configuration ...

We will have the Cirrus at OSH after a lot of flying to get empericle data so numbers won't "fluff" your imaginations. Might have an RV there as well but can't promise anything yet.

Thanks for allowing this "new guy" to post here. I hope to meet all of you and get to know those who have had the privilege and the joy of flying the Vans line of A/C. One thing I can truly appreciate about Mr. V..... He went out and did it himself. We know all too well what that can mean in years off your life and money spent just to get you up to the plate to bat.

Kind Regards, safe travels to all.
JP
 
Now, if you can just get some engines to market for a price somewhat less than the cost of an entire RV, you might just have something.
 
BTW

Mike, your quote reminded me of what is always said when rating importance in flying. "Aviate, navigate, communicate, in that order"
 
Now, if you can just get some engines to market for a price somewhat less than the cost of an entire RV, you might just have something.

I love the idea of putting this engine on an RV, but would have a really hard time justifying the cost. No matter how cool it is and how bad I want a diesel, unfortunately even with the decreased operating cost, you still have to pony up an astronomical amount before you even gas up the first time. A Lycoming may be more expensive to operate, but at least that cost is spread out over time as you fly. If avgas goes away completely we may not have a choice, but until then I don't think I can justify doubling the cost of my future RV.
 
"Accidental A4"

We are endeavoring to "accidentally" turn one vertical, but is proving difficult to get one to "fall over" vertically.

JP
 
I love the idea of putting this engine on an RV, but would have a really hard time justifying the cost. No matter how cool it is and how bad I want a diesel, unfortunately even with the decreased operating cost, you still have to pony up an astronomical amount before you even gas up the first time. A Lycoming may be more expensive to operate, but at least that cost is spread out over time as you fly. If avgas goes away completely we may not have a choice, but until then I don't think I can justify doubling the cost of my future RV.

That's me also - I've been dreaming of a turbodiesel in my place since I ordered the empennage - but I just can't justify even HALF of the advertised cost of the Deltahawk.

Maybe the next one... (sigh)
 
Cost of Panty Hose

Gents, the first pair of pantyhose cost over a million dollars in 1940 dollars. The first engine on my aircraft that flew exactly 10 years ago today costed well north of 5 million dollars.

As I tell my wife as I'm eyeing a lovely lady pass, "Don't worry Babe, I'm just looking at what a million dollars brought out of the 40's"

I could have easily said "I'll just accept the status quo and enjoy a nice Lycoming with the canard pusher". Thank goodness, some people think there might be a better way and risk something more than just money/reputation. I'm sure Mr. V had thoughts such as mine as well and struck out on his own defining moment. If we succeed then we will certainly change the world for the better. If we fail, then we will be just a footnote in some aircraft forum that said, "what's happened to DeltaHawk? Haven't seen anything on them in years." I'm certain of the former and will tell my grand kids someday when they ask what I did to help change the world..... As Patton said ".... I won't have to say I shoveled sh_t in Louisiana" ( although, I have shoveled plenty of the finest barnyard variety in my youth on a farm in downstate Illinois).

So, why spend 8 figures of $$$$? Diane Doers and I twisted Doug's arm to get him to design what we knew he was a genius at.... He made the statement in 1994 " I can't build this engine!...it might take three years and cost a million dollars".

JP
 
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Gents, the first pair of pantyhose cost over a million dollars in 1940 dollars. The first engine on my aircraft that flew exactly 10 years ago today costed well north of 5 million dollars.

As I tell my wife as I'm eyeing a lovely lady pass, "Don't worry Babe, I'm just looking at what a million dollars brought out of the 40's"

I could have easily said "I'll just accept the status quo and enjoy a nice Lycoming with the canard pusher". Thank goodness, some people think there might be a better way and risk something more than just money/reputation. I'm sure Mr. V had thoughts such as mine as well and struck out on his own defining moment. If we succeed then we will certainly change the world for the better. If we fail, then we will be just a footnote in some aircraft forum that said, "what's happened to DeltaHawk? Haven't seen anything on them in years." I'm certain of the former and will tell my grand kids someday when they ask what I did to help change the world..... As Patton said ".... I won't have to say I shoveled sh_t in Louisiana" ( although, I have shoveled plenty of the finest barnyard variety in my youth on a farm in downstate Illinois).

So, why spend 8 figures of $$$$? Diane Doers and I twisted Doug's arm to get him to design what we knew he was a genius at.... He made the statement in 1994 " I can't build this engine!...it might take three years and cost a million dollars".

JP

So are you saying the price of these engines will decrease as production ramps up and R&D expenses are paid off as in the other mass produced items you mentioned above? That would be a breath of fresh air in the aviation industry.

At the current price, assuming the engines go to TBO with no work and burn 20% less fuel than a Lycoming, they don't make economic sense. The up front costs vs. fuel saved will never reach a point where they will save money over a Lycoming in the first use cycle, especially if we invest the initial savings at 5-8% compounded return.

The only markets then I see at this price are:

1. Military
2. Where avgas availability and/or price makes using diesel or Jet fuel the only game in town
3. For people who just want a diesel or something different in their planes and don't care about cost

Your posts seem pretty realistic at least and if it is really here, you will have plenty of interest (maybe not sales though). People will be waiting to see actual side by side independent tests against a Lycoming in the same airframe, then see many thousands of reliable flight hours compiled on several examples, see how Deltahawk corresponds and treats customers, how the dealer service network is set up etc. Frankly, the initial data put out by the company comparing it to a Lycoming years ago was very slanted and didn't make sense from a technical/ engineering standpoint. It hurt the credibility of the whole project in my view.

I hope it works out and the design gives people a viable second choice. I'll be following this with interest as will many others. Onwards and upwards!:)
 
Just another data point

Apparently Glasair sees enough promise to offer it in their two weeks to taxi program in the very near future. There should also be a Delta Hawk powered Sportsman at OSH.

My Dad is planning to put one in our Sportsman, even though we have a brand new Aero Sport IO-375 sitting on the floor.

To some of the other points made, why is he doing it? Because he wants to. Is it cheaper? Probably not. Is it different? Oh yeah. With the big spinner and big scoop it should like look a turbine at first glance.

Personally, I hope they sell a million of them, or at least enough so that we can get parts for it in 5 years.
 
Don't get me wrong

JP-

Please don't take my comment about the cost wrong. I am thrilled that you guys have pushed on with the design of this engine and I have always loved the idea of it and will continue to root for you! You're absolutely right that innovation and risk are what push any industry forward. I think most of us are very glad the engine is on the horizon. My point was that no matter how great it is, for many of us in the RV world, the cost will likely be a limiting factor. That doesn't mean the quality of the engine is not worth it, it just means that many may unfortunately not be able to afford it. Kind of like not being able to afford a Ferrari, even though the cost of it may be justifiable. For me, cost is cost, no matter how much I want something (and believe me, I've wanted the DH engine ever since I heard of it years ago). I do hope you guys succeed in bringing this to market though, and I really hope that someday I can afford to go this route.
 
Not saying yr wrong, but what numbers were slanted?
JP


The SFC numbers didn't seem to jibe with the fuel flows claimed, the Lycoming was running way ROP and I recall they were making a cost comparison against the Lycoming changing plugs every 200 hours or something silly. In the real world, nobody I know changes aviation spark plugs on a Lycoming every 200 hours. Changing 8 plugs every 200 hours at the standard price added unrealistic costs to the Lycoming side of the comparison.

What kind of SFCs are you seeing at 135hp? (75% on a 180 Lycoming).

How many hours has the high time engine accumulated without being touched internally?

What is the installed weight of the engine wet?
 
Costs

Okay, I'll accept the fact you will use only one set of plugs for,the entire 1800 hours and spot you the entire amount of $1800 minus the cost of a set of eight plugs, say... $200 cost?, netting you $1600 off the difference still putting you north of $40,000 savings. Is this good for you? Well done. We apologize for being "silly".

What is the fuel flow of your TSIO-360? ...10 gals/hr? ... 11? Help me compare the numbers with you.

I know we flew the Velocity 7 hours and burned 42 total gallons... 6 g/hr?

High time engine? Ill ask Doug.

135hp. Again, I'll pull Doug away from the test cell and ask because,... It is important.

Installed weight is 15 lbs. lighter than a TSIO-360, and with modification to a part we think we can shed another 15 lbs.

JP
 
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Okay, I'll accept the fact you will use only one set of plugs
JP

GOOD. The website still has this and because it is so incredibly bogus, it ruins credibility claims on the rest of the page.

In regards to fuel costs. We obviously have to accept your numbers because you hold the cards. No issue. The Lycoming data and fuel cost data are taken from reasonable sources since it comes from factory charts and industry survey data.

If fuel consumption is to be the main life cycle costing difference, then I think Ross has a point about Lycoming ROP data vs economy (peak) fuel flow data.
Sure, not everybody runs peak so I do understand the marketing angle of using ROP data.

Secondarily, since we are talking experimentals here, many run auto fuel. In order to make the cost difference zero at the ROP Lycoming fuel flow rates, autogas for $4.10 is needed. At LOP, the allowable autogas price goes higher.

Admitedly, I imagine most experimentals don't run autogas and of course certifieds don't for the most part but these competitive pressures against you still exist.

Yes when I saw this product at 2005 OSH, I wanted one very much. Inability to answer the questions "when?" and "how much?" prevented that. Now it seems availability is close but the price is out there where I cannot justify it (because I run LOP and will be using autogas shortly)
 
DeltaHawk and the RV-14

Hi JP,
Its Colin, and it is great to hear about the DeltaHawk engine again(news was a little lacking for a while). I'm building RV-14 kit number 14. I've been waiting years to see your engine hit the mainstream aircraft market and it looks like you are inside the marker gear down and flaps to 40. Do you think you will have an option to put one on the 14? PS: I got tired of the long haul flying and went back to the 737 domestic.;)
 
Okay, I'll accept the fact you will use only one set of plugs for,the entire 1800 hours and spot you the entire amount of $1800 minus the cost of a set of eight plugs, say... $200 cost?, netting you $1600 off the difference still putting you north of $40,000 savings. Is this good for you? Well done. We apologize for being "silly".

What is the fuel flow of your TSIO-360? ...10 gals/hr? ... 11? Help me compare the numbers with you.

I know we flew the Velocity 7 hours and burned 42 total gallons... 6 g/hr?

High time engine? Ill ask Doug.

135hp. Again, I'll pull Doug away from the test cell and ask because,... It is important.

Installed weight is 15 lbs. lighter than a TSIO-360, and with modification to a part we think we can shed another 15 lbs.

JP

This is an RV site and most people here are flying atmo O-320, O-360 or IO-360 Lycomings in their aircraft. Running LOP, which many people do here, and mogas, people are flying around at 6.5 to 8.5 gph, depending on engine and power setting.

The installed dry weight on a TSIO-360 is 401 lbs. http://www.tcmlink.com/EngSpecSheetDocs/TSIO360LB.pdf

Engine weights from Lycoming:

O-320 B 277-283 lbs dry weight
O-320 D 278-286 lbs dry weight
O-360 A 285-301 lbs dry weight
O-360 D 280-281 lbs dry weight

Add 20 lbs. for oil and baffles.

So are you saying the Deltahawk weighs about 100 more lbs. than the Lycoming? It would be easier just to tell us what the wet weight is rather than letting people guess by being vague. Different models of TSIO-360s weigh differently.

Also, you could redo your comparison chart showing the current prices of both engines and current TBOs, Most of the Lycomings are at 2000 hours now. Will the FAA approve an initial 2000 hour TBO on the Deltahawk upon certification?

Not showing the initial acquisition costs makes the whole comparison a bit meaningless IMO. Also, you went to great lengths to justify the high cost of the first run engines, comparing them to other new products but then never answered the question- would prices come down as production went up? If prices climb, I think you will have a very hard sell in the RV market.

I am not trying to be hard on you, just trying to get some real numbers for comparison. In the past, many new engine vendors have been vague about details and it hasn't gone over well when the real numbers came out later. I think it is best if people just put it all out there for everyone to see.
 
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Colin

Good to hear from you my Friend. Dynamics at AA sure keep us guessing, yes?

I'm going to be superficial here. When we do an RV, then you will see the numbers, then you will see the price, then you can walk away. I so understand.

So Gents, I thank you for the time and hope to shake your hands.

Ill be letting the numbers talk from here on so we will have those soon as we can.

Kind Regards,

JP
 
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What is the fuel flow of your TSIO-360? ...10 gals/hr? ... 11? Help me compare the numbers with you.

JP

I do not think there are many ( if any) TSIO 360 installations in RVs, mostly O 360, or IO360.

Seems to me that they usually burn 7--8 in cruise.

I burn 9.5---11 in my IO 540, depending on load and altitude.

DSC06106.jpg
 
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If we are to be honest in comparisons, we really need to use honest 75% numbers for Lycs. Yes, you can get burn down under 7 gph, but not at 75%. Want to know your 75% number (at least a close-to-realistic number)? Go to 7500-8000ft density altitude, full throttle, set prop for 2700 rpm, when leaned for best speed. Flow at those settings will be pretty close to 75%. A 360/180 will be right at 10-10.5 gph, maybe *slightly* less if injected. Can't fool Mother Nature....

The same thing needs to happen with the DH, but they need to find a way to honestly establish 75%, since they are 'boosted' & that, like money, changes everything.

Charlie
 
If we are to be honest in comparisons, we really need to use honest 75% numbers for Lycs.

I certainly agree with this but the problem is that even the lycoming data for my IO-360-M1B gives a range of 9.1 to 11.5 gal/hr FOR THE SAME 75% HP, depending on the rpm/mp and mixture combination used.

I choose to operate 75% at 9.1 gal/hr. I do not challenge DeltaHawks comparison in this regard when they use a higher figure simply because I think there are many many pilots that do not lean to best economy (especially at 75% even though Lyc allows it). In one way of thinking, the numbers used are appropriate. They are not for my circumstance.

This leaves us with the basic problem of what are "honest numbers" for Lycoming? It may simply require an honest assesment by each individual buyer to compare his own Lycoming operating habits aginst the Deltahawk.
 
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Good to hear from you my Friend. Dynamics at AA sure keep us guessing, yes?

I'm going to be superficial here. When we do an RV, then you will see the numbers, then you will see the price, then you can walk away. I so understand.

So Gents, I thank you for the time and hope to shake your hands.

Ill be letting the numbers talk from here on so we will have those soon as we can.

Kind Regards,

JP

Yup, that's what I was afraid of, and pretty much expecting.
 
Very disappointing... Guess they are not ready yet but it's a further blow to their credibility in my view, to start posting and then back away from a few of the important questions people would want the answers to before they plunk down 60K. Hmmm no weight or sensible SFC or fuel flow numbers from the dyno after all these years?
 
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Installed wt.

345 lbs. installed weight with another 15 lbs lighter with a permanent part modification. (330 lbs. after change. DH 160/180).

I've enjoyed talking with most of you. Like all pilots, we come in all varieties, ...most better than others.... And "others" tend to make mistakes overestimating their importance and attention span of those they talk with. Those are the ones we tend to watch closely in any cockpit.

JP Brooks
F-4/3000+ hrs
B777/8000+ hrs
DH co-Founder
(Disclaimer, not an RV builder and don't pretend to even play one on TV)
Cheers Gents!
 
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345 lbs. installed weight with another 15 lbs lighter with a permanent part modification. (330 lbs. after change. DH 160/180).

I've enjoyed talking with most of you. Like all pilots, we come in all varieties, ...most better than others.... And "others" tend to make mistakes overestimating their importance and attention span of those they talk with. Those are the ones we tend to watch closely in any cockpit.

JP Brooks
F-4/3000+ hrs
B777/8000+ hrs
DH co-Founder
(Disclaimer, not an RV builder and don't pretend to even play one on TV)
Cheers Gents!

Thanks. The weight isn't bad at all, especially the 2nd figure.

The SFCs on the site puzzle me. It looks like .43 there in the cruise range which is higher than a Lycoming, variously listed at between .39 and .42, depending on mixture and model. I know Jet or Diesel fuel is heavier per gallon than Mogas or Avgas but where are the big fuel flow savings coming from you mention in your site? How can you have lower fuel flows when the SFCs are not as good?

The big Contis are around .375 LOP in cruise.
 
I've enjoyed talking with most of you. Like all pilots, we come in all varieties, ...most better than others.... And "others" tend to make mistakes overestimating their importance and attention span of those they talk with.

JP Brooks
F-4/3000+ hrs
B777/8000+ hrs
DH co-Founder
(Disclaimer, not an RV builder and don't pretend to even play one on TV)
Cheers Gents!

JP, pretty sure most of us have enjoyed your input here as well.

You need to understand that many folks are skeptical of new engine offerings, usually rightly so.

Remember Innodyn?? Zoche?? Mistrail?? Dynacam?? and a host of others I cant name off the top of my head.

I am very glad you have a flying example if the DH, and that you and the rest of the company have been able to stick with it for the years needed to reach this milestone.

I truly do wish you all the success possible, and I would guess that 99% of the rest of the followers of this thread do too.

I sincerely doubt if anyone wishes you failure.

People are asking for facts and figures because they are interested in the potential offered by your engine, and not just to find fault with it.

There are a lot of technically savvy individuals on this forum, and they like to see firm documented data, and not generalities.

You list 3000 hours in F4s, (and thanks for the service it took to achieve that) and 8000 in triple 7s, which is ample proof of your competency as a pilot----------but what I and many others here are interested in is how many hours does your Velocity have with the DH??

Carry on, keep us informed. I and many others would like to someday fly with one of your engines on the nose of our planes.
 
JP,

You have my respect and admiration. Thank you for sharing.

I understand your frustration. Clean-sheet engine design and production can't be easy. I'm a +1 to all those who have been keeping DH in the corner of my eye for the last 5-6 years and am glad to hear the project is not dead and additional info is pending.
 
This thread has been moved to the "Alternative Engines" forum, for later ease in locating it.
 
Thanks. The weight isn't bad at all, especially the 2nd figure.

The SFCs on the site puzzle me. It looks like .43 there in the cruise range which is higher than a Lycoming, variously listed at between .39 and .42, depending on mixture and model. I know Jet or Diesel fuel is heavier per gallon than Mogas or Avgas but where are the big fuel flow savings coming from you mention in your site? How can you have lower fuel flows when the SFCs are not as good?

The big Contis are around .375 LOP in cruise.

Maybe you have hit the nail straight on the head here. The SFC on a normal modern 4 stroke TDI is much lower than this, typically 0.3 or lower. Maybe this is what you have to pay for piston ported lay out? The Wilksh has overhead valves just like the big marine two strokes. What is the SFC on the Wilksh?
 
Maybe you have hit the nail straight on the head here. The SFC on a normal modern 4 stroke TDI is much lower than this, typically 0.3 or lower. Maybe this is what you have to pay for piston ported lay out? The Wilksh has overhead valves just like the big marine two strokes. What is the SFC on the Wilksh?

The WAMs stated SFC is not that good either (stated at .43-.45 in cruise- again- about the same as a Lycoming running lean) and in fact people with O-235 and IO-233 Lycomings report pretty similar fuel flows and speeds (around 5.25 gph at 65% power). We really should be measuring weight of fuel burned not volume in operating comparisons. When max range is considered, the higher density of diesel or jet fuel is an advantage if you have the gross weight capability to lift it all.

2 stroke diesels have good power to weight ratios for aircraft but the 4 strokes have better SFCs.

The thing with the Deltahawk figures is that their specs don't make logical sense which is why I asked for the clarification. I questioned another designer who was claiming .26 SFCs (ludicrous for a SI engine) on an LS1 powered design and was simply met with anger and no explanation. Lots of questionable SFC claims out there.
 
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Interesting. But the low SFC of modern 4 stroke diesels have happened only during the last 10-15 years. I think a traditional (old school) diesel is considerable higher. But the density of diesel fuel is much higher than gasoline, about 10%, so a diesel will use less litres per km.
 
2 stroke diesels have good power to weight ratios for aircraft but the 4 strokes have better SFCs.

Both the WAM & the Deltahawk have indirect mechanical injection for simplicity & easier certification. Direct injection especially with electronic control would probably improve the SFCs of the 2-strokes.
 
A sincere "thank you"

J I've enjoyed talking with most of you. Like all pilots said:
JP,
Welcome to VAF! Unfortunately you've found that there are some on this forum who are unfriendly towards aerodiesels. They'll say that it's because you don't give them enough facts - but that's not really true. I've provided solid data that shows the WAM two stroke diesel measures up to it's Lycoming equivelant in every way, while being considerably more efficient. I've even provided side-by-side, same day-same- way fly-off comparisons (written by Van's head engineer himself) between the diesel and Lyc. powered RV9's. The WAM fleet has 1000's of trouble free hours. But this forum always seems to gravitate to a "your (fill in the blank)-will-never-be-as-good-as-a-Lycoming" forum.

I look forward to the day when I can personally thank you for your vision, patience, and investment in developing the DH aerodiesel. Few people have the courage or the means to embark on such a project. Few understand what it takes to develop a new engine and make it work.

I assure you that there will be plenty of buyers for the DH once it is available. I'm one of them. Most of the GA world sees the writing on the wall and is looking forward to seeing sensible lightweight Jet-A powered aircraft become more mainstream. So don't give up, no matter what the naysayers throw at you!

Kurt Goodfellow
RV9 WAM 120 diesel, 440 hours, zero problems.
 
JP,
Welcome to VAF! Unfortunately you've found that there are some on this forum who are unfriendly towards aerodiesels. They'll say that it's because you don't give them enough facts - but that's not really true. I've provided solid data that shows the WAM two stroke diesel measures up to it's Lycoming equivelant in every way, while being considerably more efficient. I've even provided side-by-side, same day-same- way fly-off comparisons (written by Van's head engineer himself) between the diesel and Lyc. powered RV9's. The WAM fleet has 1000's of trouble free hours. But this forum always seems to gravitate to a "your (fill in the blank)-will-never-be-as-good-as-a-Lycoming" forum.

I look forward to the day when I can personally thank you for your vision, patience, and investment in developing the DH aerodiesel. Few people have the courage or the means to embark on such a project. Few understand what it takes to develop a new engine and make it work.

I assure you that there will be plenty of buyers for the DH once it is available. I'm one of them. Most of the GA world sees the writing on the wall and is looking forward to seeing sensible lightweight Jet-A powered aircraft become more mainstream. So don't give up, no matter what the naysayers throw at you!

Kurt Goodfellow
RV9 WAM 120 diesel, 440 hours, zero problems.

I think WAM has a lot to be proud of compared to every other aero diesel manufacturer to date. They have delivered a reliable, weight competitive and cost competitive aero diesel (in a reasonable time period and on a fraction of the budget too), something that Zoche, Thielert and SMA didn't. Call me skeptical when it comes to big companies and drawn out development in this field.

DH has missed the boat of cost by a wide margin and they have no track record of performance and reliability to date. Assuming they demonstrate equal or better reliability compared to Lycomings, they will still never save money overall unless the purchase price comes way down. $30K buys 5000 gallons of 100LL or 8000 gallons of unleaded.

I'm not trying to be unfriendly here, just get some explanations about costs and SFCs. WAM had this sort of info available long before they delivered the first engine as you'd expect from a serious, reputable manufacturer. In the past, reluctance to answer technical questions about new engine designs has almost always shown that something was not so impressive and did not stand up to scrutiny. Potential buyers are going to want to know this stuff I believe. When you have all the answers and it is the truth, your credibility in the eyes of customers just went way up. I am sure that anyone can see here, including DH, that they are a bit low on credibility at this point after all the years and announcements coming and going. They can start turning that the other way with some straight answers.

Finally, it is ok to like Wankels, Subarus, Lycomings, diesels or whatever you want. There are advantages and disadvantages to each. I believe you should fly with whatever turns your crank so to speak. However the numbers speak for themselves and we know from a poll here on VAF that several RV9/As with O-360, O-320 and O-235 power running lean and with partial carb heat, post FF/TAS numbers similar or even better than the WAM powered ones. http://www.vansairforce.com/community/showthread.php?t=60930&highlight=rv9+performance This is despite a 10% BTU deficiency per volume fuel. No magic here since the DH and Lycoming have similar SFCs in cruise which is why the question of SFCs is important.

In the Van's test, the WAM was inferior in both ROC and speed to the O-320, despite being turbocharged and used more energy to complete the first performance flight even though it was going slower. As I have said before, it is more comparable in weight and performance to the O-235. The article also stated that the WAM was allowed to dictate the cruise tests profiles to its best advantage where it came out on top by a fair margin so this is no surprise perhaps and we are not told if the O-320 was running LOP or with partial carb heat which makes a fair difference in FFs. There were other factors of course, different props, one aircraft was a taildragger and one an A model with consequent weight and drag differences and at the same time the WAM -9 probably could have benefited from a cleaner cooling system too.

This test did however allow us to see a comparison and I found it very interesting technically. Thanks again for having the confidence in the engine to do this, I love articles like this.:)

The point I am trying to make here is that while we might believe something is clearly better in all respects, impartial scrutiny often shows otherwise as I found out in my side by side with an O-360 RV6A also featured in Kitplanes years ago. I couldn't deny that the Lycoming was superior in almost every performance test below 12,000 feet because the true facts were right there for me to see. Enthusiasm should be tempered by reality and engine choices determined by your mission and preferences. We all have different important criteria so there is no one "right or only" engine choice for everyone.

I'll stand by my earlier statement that the markets for the DH at its current pricing will be restricted to the 3 types of buyers for now. If aviation gasoline disappears at airports and is replaced only with Jet A, I am going to be in the market for an aero diesel too and I hope something like a 180-200hp WAM is available by then. I have less confidence that DH would be able to meet my price point. Diesels will be an important part of the future of GA, no doubt about that but I believe there will be unleaded avgas in the not too distant future and there will still be plenty of SI engines flying too, just like in the automotive world where there are also two choices.
 
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I have less confidence that DH would be able to meet my price point. Diesels will be an important part of the future of GA, no doubt about that but I believe there will be unleaded avgas in the not too distant future and there will still be plenty of SI engines flying too, just like in the automotive world where there are also two choices.

Maybe diesels will be more plentiful for larger certified aircraft with 1000+ flight h per year, but for smaller and uncertified aircraft they are too complex, too heavy and becomes too expensive. Besides, all the way from 30 to 200+ hp there are new engines available that runs on any autofuel, even with ethanol/methanol, so the need for a single replacement for 100LL is becoming increasingly irrelevant.

It is really rather backward trying to formulate a fuel to run on 50-60 year old engine technology when modern engine technology have since long moved way past the need for such a fuel.
 
Too complex? Too heavy? Too expensive?

Maybe diesels will be more plentiful for larger certified aircraft with 1000+ flight h per year, but for smaller and uncertified aircraft they are too complex, too heavy and becomes too expensive. Besides, all the way from 30 to 200+ hp there are new engines available that runs on any autofuel, even with ethanol/methanol, so the need for a single replacement for 100LL is becoming increasingly irrelevant.

It is really rather backward trying to formulate a fuel to run on 50-60 year old engine technology when modern engine technology have since long moved way past the need for such a fuel.

The current 4-stroke aerodiesels are too heavy, complicated, and expensive. But it does not have to be that way. The Wilksch in my RV9 is lighter, extremely simple, and no more costly than its equivalent Lycoming. And it's much cheaper to fly. The DH is even simpler.

These "new engines" you refer to, that run on auto fuel, are also expensive, and some are pretty complicated, definitely more complicated than a WAM, IMHO.

I agree that it's backward to develop a new fuel to replace avgas, but the current fleet of traditional engines is quite large and many can't survive without it. I agree with Ross, the 100LL replacement will be developed, but there is no question that it will be very expensive, as if 100LL is not expensive enough already (at most airports I've been to lately, it's almost $1.00/gal more than Jet A).

I'm not saying that diesel / JetA is the final answer to GA's problems, but it's one of the answers. It sure has been good for me.
Kurt Goodfellow
 
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