Yes Sir. I read every post and there is some missing info. I have followed alternative engines (meaning not Lycoming) the mid 1980's. I have followed Delta hawk for over 20 years. I know a lot about it. I am also opinionated, I admit that. I am not keen on deviation from Van's plans, especially on recommended important parts, the engine, prop. I am conservative with aircraft designs and mods. That is me.
Yes alternatives "work" but most are not as good as Lycoming (overall for me) in my opinion. What do I mean by not work as good? One or more: Performance, Reliability, Ease of Installation, Maintenance, Weight, Value, and Resale. The exceptions can match just match a Lycoming in some categories, but all are by DIY'er, with time, skill, money, and determination to take a stock automotive engine from nothing to mounted in the nose of your RV. The off the shelf ones like "Eggenfellner" was not great in my opinion. However Ross of SDS ignitions has a Subaru powered RV-6 that he has been tinkering with for a long time. It works, but he is Ross who makes CPI-II ignitions. He knows stuff. Average builder does not have the wherewithal to get similar results. He also has had issues. but again time, perseverance, resources, skill, desire... he has worked through them. In the end it is not faster, lighter or aerobatic and definitely not cheaper.
We love experimentation. I have seen in my years in EAA over 30 years all the next "Lycoming Killers". I know no one is saying that here for Delta Hawk, that it is a Lycoming killer. Just the price is a market issue.
Alternative engines, Mazda 13B, Subaru, Ford V6, Buick V6, LS 3 V8 all been done. For the most part the planes that swap out a Lycoming for one of these are heavier, slower and fetch lower resale. Now there are exceptions as mentioned. People have finessed with very cleaver work and 1000's of hours to get good performance and reliability. Still not better than a Lycoming.
The BIG SHOW STOPPER for me, which Delta Hawk does not have, with most alternative engines are PSRU's. All the car engines (with exceptions) run higher engine RPM and use PSRU. I do not like them. Belt or Gear they to me are a weak point and have proven to be problematic. Again not unilateral guaranteed to fail, but a weak point. Also it assures you the plane is not aerobatic and often can not use a hydraulic CS Prop. Is the Delta Hawk Aerobatic? I know it supports a hydraulic CS Prop.
I am leaving off the Alternative low HP VW, Corvair, Honda, Suzuki (car), Mitsubishi (car) in the sub 130 HP range, not suitable for "full sized" RV's. However several RV-12's. I am sure are sporting a Viking (Honda Car Engine) or Aeromomentum (Suzuki Car Engine) auto engine based set up. I do like the "Fly Corvair" with the flat 6 Cyl air cooled direct drive with all the mods. VW flat 4 air-cooled was an early auto to airplane engine for tiny planes like Q2 and KR2. I want to like the VW but seen too many crank failures.
There are the boutique aircraft engines, ROTAX, Jabiru, UL Power. I admit I was wrong about Rotax 20 yrs ago. Clearly Rotax being bought in 1970, now part of a global behemoth Bombardier, with 1989 UL912 flat 4, water/oil cooled geared engine, perfect fit for the LSA class of plane, it's an established success. PSRU? Yep it works but not 100% trouble or maintenance free. I have 4 hours of recent time in a RV-12iS. Hey it works and 4.5 gal/hr at about +110 kts. Not shabby. Rotax is no longer an alternative engine. It is the de facto LSA engine. However a top of line UL915 is $44K. That is a show stopper. Also the drag issue of radiators less critical on 100-130HP planes that typically top out at 135 MPH. Drag goes up exponentially with speed. The weight to power is good. I thought the high RPM would bother me but it's not bad. You are turning +5000 RPM up to 5500 RPM in cruise.
The Jabiru another approved LSA engine was bad at first when it came to market 1995. They are on Gen 3 and I hear have overcome the issues of past. AIr-cooled direct drive. fine. However I know people had early ones. Cost them a lot in time and money. So buyer beware, Don't buy a NEW engine until it has service history. Also Jabiru is out of country made product. Not as well supported as "Lycoming".
Last is UL Power. Not against them, direct drive, air-cooled, but feel the reliability and actual pwr vs advertised are not there. Why? I look at UL Power engine user groups. Again cost more than a Lyc. and makes less actual power, not aerobatic. It is lighter and to mount on an RV you need an engine mount extension adapter and longer cowl. All the engineering van did to fit a Lycoming is out the window.
Which leads me to my canned advice, to anyone who cares to listen and is interested in NON LYC power for their RV as specified by Van's the following:
"Before you buy and invest in an Alternative Engine, talk to 3 people who own an alternative engine and are flying it. I do not mean bought it and it sits in crate in corner of hanger. When I say fly it, I mean well over a year and well over 100 hours, better 1000 hours of flight time, at least total. Last is fly in a plane with the engine. and don't accept manufactures claims without verification."
LOVE Diesels. I drive a diesel car, VW TDI and got 51 mpg on a recent short 400 mile road trip. I am all about diesel. The price for Delta Hawk however is too much for me. I very much want Delta Hawk to work and work well. At this point in my life, God willing 20-25 more years of flying I doubt I will own a Delta Hawk. But I want YOU TO. Ha ha.
For me, personally too much risk or should say unknowns, not enough reward if all lines up. I want to bolt up a Lycoming and Hartzell and go fly. Done and Done... I do not want to be a beta tester or invent new things.
Cooling drag - Getting a radiator in an RV that is super low drag is not straight forward. The technology of air-cooled engines, the engine itself, the cowl, baffles is not nothing. It has some serious NACA NASA research behind it and pretty much optimized as good as it gets over 100 years. To be fair water cooled aircraft engines go back to Wright Bros. However post WWII all piston planes zoomed in on air-cooled. It was for reasons. P-51 airframe was made for the V12 and a radiator. Do you want to put a belly scope on your plane. The RV was made for a tractor drive, air-cooled Lycoming. Not saying water cooled can't be done, but it will be more than bolting in a radiator and some glass work on cowl to get optimal low drag.
Question yet to be answered side by side. RV-7/14. - One has Lyc IO360 (180HP) the other Delta Hawk (180HP). Top Speed? Fuel Burn? We expect the Delta Hawk to do better but how much better? We may never know. I find claims often don't meet reality. Now we have ADS-B to spy and tell the story. I looked at an alternative engine RV-8 recently. It was slower than a Lyc powered RV-8. I don't know winds or if they were in min FF Econ... My finding with all the RV's with car engines they are heavier, slower than Lyc versions. There are exceptions and those just match a Lycoming and also lose the aerobatic capability. Resale in Alternative Engine planes also less than a Lycoming built to plans RV. I have been tracking this for +30 years.
Cessna 182 JT-A
diesel-
engine Skylane dead. Why? As I understand it worked fine but the cost primum to buy vs fuel savings was not enough. There are conversions and may be very desirable in places like Africa. However for now 100LL is plentiful. As I said I drive a VW TDI Diesel. It does get better MPG and fun to drive with low down torque. However a Prius gets about the same MPG (but boring).
Cessna's admission this week that it now has no definite timeline for its 182 JT-A invites speculation. Or maybe I'm the only one who can't resist asking what's going on in Wichita, says blogger Paul Bertorelli in today's AVweb blog.
www.avweb.com
70 MILLION passenger cars are made EVERY year (not including trucks, commercial vehicles). How many planes are made all up Standard, EAB and LSA. A tiny fraction of cars. I would say more cars are made in a year than all of GA all time may be? Currently there are about 340,000 GA planes world wide, about 204,000 flown. Remember ONE YEAR 70 million passenger cars made, year after year. So the economics are different. Yes the DA62 at $1.5 million sells with twin diesels. However the market will saturate. It is a tiny 5 place plane. (I read some places 7 place?) A Beechcraft Baron is bigger, holds more and as fast or faster. A nice Baron, used but well appointed, with good times and maintenance is under a million. Fuel burn? Sure higher but if you can afford this, fuel is not the big thing. I think that the calculation of savings from lower fuel burn alone, going to pay for the added expense, is not sound. Not at 100 or 200 hours of flight time a year. The cost of DA62 or Delta Hawk over a 180HP Lycoming is not sound on financial basis.
(* DA62 accident due to loss of power from electrical failure and fuel/ignition dependent . The Baron's engines are independent of ships electrical busses. I will say ALL alternative engines are electrically dependent. )
Delta Hawk did a great thing getting certification. I am impressed, but many aviation things get certification and go no where. New airplane design certified and goes no where. Only time will tell if this is a hit or miss. Even if not popular does not mean it is bad. Just a Market thing. Aviation is a tough space to make money. A new fixed gear single piston engine Cirrus cost what?