REFLECTOR: STD-RG Performance
Grover McNair
grover at mcnairperformance.com
Wed Nov 21 08:09:04 CST 2012
Dave,
This is interesting. It brings up a few questions. What is the distance from
the exhaust tips to the prop? It looks like there may be some paint that has
come off because of the exhaust blowing directly on the prop. Have there
been any issues because of this? Do you know how hot the prop is getting? Is
this an MT constant speed prop? I like the idea but am concerned about the
longevity of the prop.
Grover McNair
173LW
N832AB
_____
From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of Dave T Nelson
Sent: Tuesday, November 20, 2012 6:07 PM
To: reflector at tvbf.org
Subject: REFLECTOR: STD-RG Performance
Not sure if this will make it through the reflector or not, but here's a
shot of my exhaust....
(See attached file: IMG_1045.jpg)
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 <jerry at jlbent.com> on Tue, 20 Nov 2012 16:22:57 -0500
-----
To:
Velocity Aircraft Owners and Builders list <reflector at tvbf.org>
Subject:
Re: REFLECTOR: Early model Velocity RG Engine Cooling (Now - which
performance mods)?
Hey Dave,
I would be interested in description of your exhaust. Better still a
picture. I don't quite understand how it exist aft of the prop.
Jerry Brainard
Jerry at JLBEnt.com
-------Original Message-------
From: Dave T Nelson
To: reflector at tvbf.org
Subject: Re: REFLECTOR: Early model Velocity RG Engine Cooling (Now - which
performance mods)?
Sent: Nov 20 '12 3:05pm
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 aer! odynamic 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" on Tue, 20 Nov 2012 10:38:47 -0500
-----
To:
Velocity Aircraft Owners and Builders list
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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----- Message from Scott Baker <scottb33333 at gmail.com> on Tue, 20 Nov 2012
16:30:39 -0500 -----
To:
geoff.gerhardt at gmail.com, Velocity Aircraft Owners and Builders list
<reflector at tvbf.org>
Subject:
Re: REFLECTOR: Need some advice/measurements
Awesome video !!
Scott B.
On 11/20/2012 2:51 PM, Geoff Gerhardt wrote:
> I had to move my SE-RG in and out of my shop (single-car garage door)
> a couple times. Here's how I did it. I wouldn't try this with an
> engine on, tho. Its relatively easy to pull an engine off, tho.
>
> http://thegerhardts.com/velocity/?p=292
>
> There's a video in that post that shows my wife and I moving it out of
> the shop on a cradle.
>
> Geoff
>
----- Message from none <markinchampions at gmail.com> on Tue, 20 Nov 2012
15:58:50 -0600 -----
To:
"jerry at jlbent.com" <jerry at jlbent.com>, Velocity Aircraft Owners and Builders
list <reflector at tvbf.org>
Subject:
Re: REFLECTOR: Early model Velocity RG Engine Cooling (Now - which
performance mods)?
Me too.
On Nov 20, 2012, at 3:22 PM, < <mailto:jerry at jlbent.com> jerry at jlbent.com>
wrote:
Hey Dave,
I would be interested in description of your exhaust. Better still a
picture. I don't quite understand how it exist aft of the prop.
Jerry Brainard
<mailto:Jerry at JLBEnt.com> Jerry at JLBEnt.com
-------Original Message-------
From: Dave T Nelson
To: <mailto:reflector at tvbf.org> reflector at tvbf.org
Subject: Re: REFLECTOR: Early model Velocity RG Engine Cooling (Now - which
performance mods)?
Sent: Nov 20 '12 3:05pm
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 aer! odynamic 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" on Tue, 20 Nov 2012 10:38:47 -0500
-----
To:
Velocity Aircraft Owners and Builders list
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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To change your email address, visit
<http://www.tvbf.org/mailman/listinfo/reflector>
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Check old archives: <http://www.tvbf.org/archives/velocity/maillist.html>
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Check new archives: <http://www.tvbf.org/pipermail> www.tvbf.org/pipermail
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