REFLECTOR: Engine Selection

[J.P. Brooks]

most efficient blade would be a single blade with a counter-weight.....yes?


At 10:43 AM 6/17/2004, you wrote:
>To each his own.  You can always go faster with a bigger engine, but to me 
>the weight and fuel consumption penalty for anything over 200 hp in a 
>plane this size isn't worth it.  That's just me.  A lot of guys like to 
>build the biggest, baddest airplane they can.  I love it.  More power to 
>them (literally.)  It takes all kinds of people to make up a world.  I'm 
>one of those "less is more", "think smarter not harder" kind of guys.  I'm 
>shooting for 180 mph and 25 mpg at 9,000 feet with my top door, short 
>wing, fixed main gear, retractable nose gear Velocity.
>
>I'm disappointed to hear that propellers are not more efficient at lower 
>RPMs. I was hoping that extra efficiency would give my diesel a little 
>free speed boost.
>
>Doug
>----- Original Message -----
>From: <mailto:ALVentures at cox.net>Al Gietzen
>To: <mailto:reflector at tvbf.org>'Velocity Aircraft Owners and Builders list'
>Sent: Thursday, June 17, 2004 11:22 AM
>Subject: RE: REFLECTOR: Engine Selection
>
>Just a couple of comments on this power, efficiency and speed 
>thing.  Torque is a measure of force; HP is a measure of work; force times 
>time – or acting through a distance.  So it is the HP that does the 
>job.  Hp is simply torque times rpm.  You can have high torque a lower rpm 
>but if it gives you the same HP you’ve gained nothing; unless the prop was 
>more efficient at lower rpm.  I thought this was true as well – until I 
>studied some prop performance charts and found it wasn’t true.
>
>
>
>160; 180; or 200hp – IMHO, these are all low for a fixed gear 
>173.  Getting 161 mph at 5500 ft with 160 hp translates to 173 mph with 
>200hp (remember; speed goes as the cube root of power).  That’s 153 
>kts.  Hardly impressive.
>
>
>
>Al
>
>
>
>Subject: Re: REFLECTOR: Engine Selection
>
>
>
>Plenty of power. He's got a 173 RG. The Velocity was originally designed 
>for 160 hp.  The DH180A4 is 180 hp up to 18,000 feet. The DH200A4 is 200 
>hp at 18,000 ft. Plus, the diesel has better torque at lower RPMs than a 
>Lycoming, and propellers are more efficient at lower RPMs. Plus it weighs 
>less if you take into account that it is 30% more fuel efficient, so you 
>don't need to carry as much fuel weight to get the same range. A DH160V4 
>is in the factory's test airplane.  With the 160 hp engine they clocked it 
>at 202 mph at 15,500 feet, and 161 mph at 5,500 feet. And that is with a 
>fixed pitch propeller.
>
>
>
>The DeltaHawk has half the moving parts of a Lycoming, no spark ignition 
>to interfere with the radios, and burns readily available and slightly 
>cheaper Jet A.  It is much smoother because it's a two-stroke. Plus, since 
>the DeltaHawk test platform is a Velocity Std RG, the firewall foreward 
>package is pre-designed.
>
>
>
>No, I don't own stock in the company. Just excited about the first 
>significant improvement in general aviation powerplants in 50 years.
>
>
>
>Doug Holub
>
>Std Top Door, 50% done, 80% to go
>
>----- Original Message -----
>
>From: <mailto:NMFlyer1 at aol.com>NMFlyer1 at aol.com
>
>To: <mailto:reflector at tvbf.org>reflector at tvbf.org
>
>Sent: Tuesday, June 15, 2004 9:18 PM
>
>Subject: Re: REFLECTOR: Engine Selection
>
>
>
>nice idea Doug... but not enough power scotty
>
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