REFLECTOR: Early model Velocity RG Engine Cooling (Now - which performance mods)?

[Rich Ervin]

I understood those to be standard numbers. I have an IO-360 200HP as well, and easily get 185 at 9.5 GPH. That plane is for sale, though the engine has been idle more than 8 years, if anyone is interested in an old (95) RG.
 > Date: Tue, 20 Nov 2012 19:16:09 -0500
> From: stedmanlou at roadrunner.com
> To: reflector at tvbf.org
> CC: dtnelson at us.ibm.com
> Subject: Re: REFLECTOR: Early model Velocity RG Engine Cooling (Now - which performance mods)?
> 
> Wow I can't believe those numbers. I am lucky to see 145kts. What HP is your 360? Do you have pictures?
> --
> Lou Stedman
> LEZ N9EC
> Olean, NY
> 
> ---- Dave T Nelson <dtnelson at us.ibm.com> wrote: 
> > 
> > I've got a STD-RG, Lycoming IO-360 and an MT prop.  I started off with
> > armpit scoops feeding into a tops-down plenum, along with a single nose
> > mounted oil cooler.  Intake air was off a second scoop mounted on the right
> > wing.
> > 
> > My situation was that I built my plane while sharing my shop with a good
> > buddy who built a really nice Cozy 3 place.  We got them both flying at
> > about the same time, and spent many happy years racing (and bragging).  I
> > still say his plane was the slow ugly one.
> > 
> > Anyway, the main thing(s) you do to make these airplanes go fast are all
> > about weight and aerodynamics.  Power increases don't get the same bang for
> > the buck.  I focused mostly on drag reduction... really clean gear doors,
> > clean canard/fuselage interface, minimum cooling drag, and clean exhaust
> > system.  The last two are the most important.
> > 
> > The armpit scoops are a bit of an aerodynamic disaster... they are all too
> > big.  If you tuft or do an oil study on them, you'll find that the bulk of
> > the air is getting pushed back out of the scoop because of the inherent
> > flow resistance of the  tubes taking the air to the top of the plenum, the
> > flow through the plenum & engine, and the output behind the prop.  An oil
> > study will likely also show nearly dead air at the output (right behind the
> > prop).  The total square inches of inlet are too great, and so is the total
> > square inches of outlet.
> > 
> > Many of my initial mods were in trying to clean up the cooling and intake
> > air..  I made several different styles of cooling air intakes, each smaller
> > than the last.  Nothing worked particularly well.  Eventually, after
> > developing significant cooling issues (which turned out to be an engine
> > issue, not an aerodynamic problem), I went to the rooftop NACAs.  As I
> > said... they work fabulously.  I take my induction air off the right NACA.
> > There are no external protrusions on my plane.
> > 
> > The exhaust changes were probably the most speed gain.  I've gone from the
> > original rear exiting 2 in 1's that exit through tubes attached to the
> > lower cowl, to the "straight out the bottom" types you see on many XLs
> > today (which were by far the worst performers - a real disaster), to what I
> > have today - a one-of design of my own that keeps the entire exhaust inside
> > the cowl and exits aft of the prop.  That was a big gain!
> > 
> > OK, performance... I see around 185 knots true +/- at around 25 squared...
> > middling altitudes... at around 10 - 11 gallons / hour ... cold air, down
> > low, with a light plane is better still.  It's not as fast as I'd like, but
> > I'm not done trying.  The next effort will be a complete cowl redesign to
> > get rid of those awful turns where the cowl angles in just aft of the last
> > cylinder.  All the attached air detaches at that point...
> > 
> > Hope this helps.  What numbers to you see?
> > 
> > Dave
> > 
> > Dave T. Nelson
> > T/L 553-4327, Voice 507-253-4327, Fax 507-253-3648
> > Program Director, ISC ECAT NPI & Test Engineering
> > 
> > 
> > 
> > ----- Message from "Richard J. Gentil" <richard at naples-air-center.com> on
> > Tue, 20 Nov 2012 10:38:47 -0500 -----
> > 
> >       To: Velocity Aircraft Owners and Builders list
> >           <reflector at tvbf.org>
> > 
> >  Subject: Re: REFLECTOR: Early model Velocity RG Engine Cooling
> >           (David Smith)
> > 
> > 
> > 
> > Dave N,
> > 
> > Which go fast mod have you done and what speeds are you getting? (Please
> > mention the engine and prop combo you are running.)
> > 
> > Thanks,
> > 
> > Richard
> > 
> > Sent from my iPhone 5
> 
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