Delta Hawk, recent Kitplane article

[dbuds2]

The DH is a little heavier than typical Io360, I was wondering about the trade between using the 160 HP DeltaHawk model, actually achieving higher Hp at altitude than a 200Hp lyc,,,and,,, using a CS prop setup to help get the TO and climb performance.
Any thoughts from the wonderful world of RV'ators?

[Jconard]

From the DH Website:

currently about 327 lbs including starter, oil pump, fuel pump, water pump, turbocharger, all internal lines and internal exhaust system


As oposed to 280 for the lyc...so about 47 lbs, before you add a couple of gallons of coolant, a radiator, plumbing, and the various support articles for liquid cooling. This will vary with the actual engine you install, etc.

I like the DH engine, but I find their numbers very suspicious, because the BSFC they quote for lycoming is MUCH higher fuel burn than any airplane I have ever flow, and the numbers for BSFC for their engine is so good that it would rival Stationay ship or train engines...that is it is almost at theoretically perfect level, and I frankly don't believe that.

In the end, it will burn less fuel volume per horsepower than current aircraft engines, but I wonder how much less, and what the installed efficiency will be with acutal weight, drag, etc factored in.

What I know for certain is that the comparison numbers they use are embelished.

[N395V]

Somewhere I had gotten the impression that there were several Velocity's flying with these engines and it was offered as an option with a firewall aft package.

If so shouldn't there be some reasonable amount of actual data available?

This was posted in 2004

[mlw450802]

Originally Posted by Jconard

... and the numbers for BSFC for their engine is so good that it would rival Stationay ship or train engines...that is it is almost at theoretically perfect level, and I frankly don't believe that...

Not quite true. The data they have published on their website seems very reasonable with a lowest BSFC of 0.4 lbs/hp/hr.

This number is easily achieved in today's automobiles and is probably closely approached in a properly leaned lycoming.

On the other hand the following quote is about a supertanker power plant:
At a length of 89 feet and a height of 44 feet, the total engine weight is 2300 tons - the crankshaft alone weighs 300 tons.

The RTA96C-14 can achieve a maximum power output of 108,920 hp at 102 rpm and astonishingly, at maximum economy the engine exceeds 50% thermal efficiency. That means, more than 50% of the energy in the fuel is converted to motion. Its Brake Specific Fuel Consumption (BSFC) at maximum power is 0.278 lbs/hp/hr.

Our engines are in the 25-30% thermal efficiency range, hence the .4 to .5 typical BSFC's

-mike
The above HP and RPM calculate out to 5,608,312 lb-ft torque! wow

[rv6ejguy]

Originally Posted by Jconard

From the DH Website:

currently about 327 lbs including starter, oil pump, fuel pump, water pump, turbocharger, all internal lines and internal exhaust system


As oposed to 280 for the lyc...so about 47 lbs, before you add a couple of gallons of coolant, a radiator, plumbing, and the various support articles for liquid cooling. This will vary with the actual engine you install, etc.

I like the DH engine, but I find their numbers very suspicious, because the BSFC they quote for lycoming is MUCH higher fuel burn than any airplane I have ever flow, and the numbers for BSFC for their engine is so good that it would rival Stationay ship or train engines...that is it is almost at theoretically perfect level, and I frankly don't believe that.

In the end, it will burn less fuel volume per horsepower than current aircraft engines, but I wonder how much less, and what the installed efficiency will be with acutal weight, drag, etc factored in.

What I know for certain is that the comparison numbers they use are embelished.

I agree, the numbers posted on their site are nonsense, who did the math on this chart? http://www.deltahawkengines.com/econom01.shtml Fuel burn numbers vs. SFCs... huh??? This is something like the numbers NSI published for their EJ25 conversions, quoting dyno numbers with nonsensical fuel flows and hp. Their SFC was .265 in one box for a gasoline engine! If engine companies expect people to swallow this "data", they are fools.

Way heavier, more expensive and at the fuel flows likely to be achieved in the real world with a 2 stroke diesel, it will take a very long time to pay for it. I'd also mention that it is relatively unproven. My advice on new engines is don't be the first one to sign up for one. Also, until jet or diesel fuel is available at many small airports, it is not practical for many.

[John Clark]

Originally Posted by rv6ejguy

I agree, the numbers posted on their site are nonsense, who did the math on this chart? http://www.deltahawkengines.com/econom01.shtml

Way heavier, more expensive and at the fuel flows likely to be achieved in the real world with a 2 stroke diesel, it will take a very long time to pay for it. I'd also mention that it is relatively unproven. My advice on new engines is don't be the first one to sign up for one. Also, until jet or diesel fuel is available at many small airports, it is not practical for many.

I enjoy the savings on spark plugs. Every 200 hours? A real stretch.

John Clark
RV8 N18U "Sunshine"
KSBA

[phil9diesel]

The Deltahawk is turning out to be a proven powerplant, but I don't see it as a desireable mate for the RV8. Vans 6, 7, and 8 are short winged aerobatic airfoiled kits, and very power and power per weight intensive. The 9 and 10 are longer range passenger planes with more appropriate flying surfaces, and better suited to take advantage of the diesel's long duration fuel cost and weight savings. If you got the Deltahawk installed and flying, it would still be a touchy beast to fly. I would personally chose the Lycoming O-320 series over the O-360, to keep your bird light, well behaved and economical and avoid the something-for-nothing options. If you can swing it, get the new kit engine. If you rebuild, be informed, unrushed, and vigilant. You can probably catch the auto diesel and gas redrive efforts on the horror channel. We have a Vans and diesels group, and you should see postings for Deltahawk, Wiltsch, and Howells Aero Engines, appearing soon. http://groups.yahoo.com/group/vansdiesel/ .