Today's Message Index:
----------------------
1. 06:54 AM - firewall penetration points / fire safety (Glen Matejcek)
2. 07:18 AM - Re: firewall penetration points (Jeff Dowling)
3. 08:30 AM - RV-8 RC Model (Ken Brooks)
4. 10:32 AM - Re: Vortex Generators (Jerry2DT@aol.com)
5. 12:30 PM - Re: Re: Vortex Generators (Aircraft Technical Book Company)
6. 12:48 PM - Re: Re: Vortex Generators (Chuck Jensen)
7. 02:24 PM - Air Bubbles in Fuel (DAVID REEL)
8. 03:23 PM - Re: Vortex Generators (Kevin Horton)
9. 03:36 PM - Re: Vortex Generators (Kevin Horton)
10. 04:15 PM - Bettery Revival? (REGAES@aol.com)
11. 05:34 PM - Camloc Group Buy ()
12. 07:59 PM - Re: Air Bubbles in Fuel (Fiveonepw@aol.com)
13. 08:36 PM - Wings before engine (DEAN PSIROPOULOS)
14. 08:47 PM - >Re:Vortex Generators (Oldsfolks@aol.com)
15. 09:41 PM - orange peel (Paul Rice)
Message 1
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| Subject: | firewall penetration points / fire safety |
--> RV-List message posted by: "Glen Matejcek" <aerobubba@earthlink.net>
Hi All-
Those are good observations, Dan. And, as with all we do with our
projects, there is lots of room for applying personal risk assessment
techniques to this topic.
First, and to answer Mark's question, I know of 2 homebuilts with fire
suppression systems. One is an -8A with a NASCAR style AFFF tank sitting
on the floor in the bottom of the fwd baggage hold. The other is a One
Design with a hand held HALON extinguisher in the cockpit. They are both
plumbed to FWF nozzles, and I believe the HALON bottle can be separated
from it's plumbing for use as a hand held.
Something to bear in mind is that the firewall isn't meant to be absolutely
bullet proof indefinitely, rather it's meant to keep you alive until the
fire is out or you can get away from it.
WRT FWF fires, a fundamental accident investigation technique is to look
for solidified droplets of aluminum on aircraft surfaces downstream of the
fire site. Their presence is a clear indication that there was fire prior
to impact. It is also clear indication that a fuel fire fed by free stream
airflow will easily generate the heat required to melt aluminum. So, what
is going to burn? Well, oil might. I will keep the FW clean, and I use
firesleeved SS braided hoses from Earl's. Of course, gasoline will burn.
More firesleeved SS hoses. So much for fire prevention.
WRT fire suppression, the fire's duration will be limited by fuel quantity.
Step one: fuel valve off. In the various fire suppression equipped
aircraft I'm familiar with, you wait 5 sec from closing valves to using the
first bottle, and then 30 sec before firing the second, assuming there are
still indications of fire. This implies to me that once the valves are
closed, the flow stops pretty quick. Having said that, I'm quite confident
that 30 sec under actual fire conditions would seem like an eternity, and
allow ample time for several bodily functions to occur autonomously.
WRT fire proofing, I believe that the somewhat localized nature of the
intense fire means that should the fire impinge upon an Al eyeball fitting,
it will most likely fail. That leaves a pretty big hole in the FW.
Likewise an Al heat box. (Mine is 100% SS) Should the fire impinge upon a
rivet line, then yes, they are also subject to failure. The question I
have is whether the sheet Al will fail before the more massive rivet. This
leads to 2 points, as I see it. The first is that even if the whole lower
FW rivet line fails, there are a whole lot more elsewhere, plus the steel
at the engine mount attach points. I don't think the FW is going anywhere.
The other point is what about the flames under the belly? The -8 has a
double floor in this area, which should be a great help. I'm contemplating
a layer of fiberfrax (sp?) in the cooling outflow area of my belly for
fireproofing, as well as thermal / acoustic insulation from the normal
exhaust stream. Has anyone done this before?
None of this is meant to flame anyone, and the extremely low incidence of
inflight fires is just what makes this whole exercise so academic. If we
have any tin kickers on the list, I'd love to hear more input on the topic.
Kevin?
>Ditto. And I wonder how all those *aluminum* rivets are gonna hold up in
>the event of a fire. I hear people yappin' about heat flapper valves and
>bulkhead fittings and eyeballs and all that, and I don't disagree. But
>nobody mentions how the firewall will basically be trying to "fall off" if
>the aluminum rivets melt in a fire. I don't know what I'm talking about,
>not speaking from experience, just kind of philosophizing here. But I
>wonder about all dem aluminum rivets. If a fat aluminum eyeball melts,
>surely the rivets will as well, right?
Dan,
I was wondering the same thing just last night. I'm just starting on the
firewall. Do certified aircraft use stainless rivets on the firewall? I was
an A&P years ago but can't remember. I don't think I ever repaired any
firewall rivets.
I had decided not to worry about it since it seemed everyone was using
aluminum rivets. And Don has the right idea...do everything right, to avoid
a fire.
Has anyone installed a fire extinguishing system on the engine in an RV?
Seems like it would be relatively simple. Mount a small halon extinguisher
somewhere where it could be reached. Then run a hose out to the top front of
the engine.
Some Cessna twins have a bottle in the wing root that is electrically
activated.
And a hose (stainless braided) runs to the front of the engine. This is from
memory from years ago...
Just a thought.
Glen Matejcek
aerobubba@earthlink.net
Message 2
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| Subject: | Re: firewall penetration points |
--> RV-List message posted by: "Jeff Dowling" <shempdowling2@earthlink.net>
Not to mention the flames burning up and through your plastic cowl and
windscreen.
Shemp/Jeff Dowling
RV-6A, N915JD
235 hours
Chicago/Louisville
----- Original Message -----
From: "Dan Checkoway" <dan@rvproject.com>
Subject: Re: RV-List: firewall penetration points
> --> RV-List message posted by: "Dan Checkoway" <dan@rvproject.com>
>
>> In general I agree with what you are saying but as far as the penetration
>> points for the Throttle, Mixture and Prop, the expensive eyeball
>> penetration gizmos are very handy, especially if you have to remove,
>> repair or
>> replace the cables for any reason later down the road (think maintenance)
>> and no need to remove a bunch of caulking at that time. And I think they
>> will hold up in a fire quite well as they are pretty beefy. Also, most
>> builders do not run the throttle, mixture or prop with other electrical
>> wires/cables through the firewall. I like using the eyeballs, they work
>> for me.
>
> Ditto. And I wonder how all those *aluminum* rivets are gonna hold up in
> the event of a fire. I hear people yappin' about heat flapper valves and
> bulkhead fittings and eyeballs and all that, and I don't disagree. But
> nobody mentions how the firewall will basically be trying to "fall off" if
> the aluminum rivets melt in a fire. I don't know what I'm talking about,
> not speaking from experience, just kind of philosophizing here. But I
> wonder about all dem aluminum rivets. If a fat aluminum eyeball melts,
> surely the rivets will as well, right?
>
> do not archive
> )_( Dan
> RV-7 N714D (736 hours)
> http://www.rvproject.com
>
>
>
Message 3
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--> RV-List message posted by: "Ken Brooks" <kenbrooks@charter.net>
McCaffrey Aviation has a plans-built RV-8 RC model for those of you who
might be interested. Photo and information can be found at:
http://home.att.net/~mgmccaffrey/ma/vansrv8.htm
It uses an 8-cell electric motor and is aerobatic. Plans are $20 and can be
previewed on their website.
Ken Brooks
Roscoe, IL
Full-scale RV-8 in Progress
Message 4
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| Subject: | Re: Vortex Generators |
--> RV-List message posted by: Jerry2DT@aol.com
Hi Bob,
Do you have any test data you could share with us? I've tried to find data
in the past on VG's, but seems to be very little.
Jerry Cochran
Wilsonville, OR
From: Oldsfolks@aol.com
Subject: RV-List: >Re: Vortex Generators
--> RV-List message posted by: Oldsfolks@aol.com
The Micro systems Vortex generators is what I have on our RV-4. I got
them
from Larry Vetterman 605-745-5932 , the exhaust system man.
Mine are aluminun,curved to wing contour and only 1/2 " tall. I love them
for the lower stall speed and the stable handling at minimun speed. I lost
nothing at top speed. I painted them to match my paint.
Bob Olds RV-4 , N1191X
A&P , EAA Tech. Counselor
Charleston,Arkansas
Real Aviators Fly Taildraggers
Message 5
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| Subject: | Re: Vortex Generators |
--> RV-List message posted by: "Aircraft Technical Book Company" <winterland@rkymtnhi.com>
I tried Micro Systems VGs on my 6A. Putting them on exactly as directed, I
didn't like them and took them off after about 10 hours.
Stall speed and the feel of the break didn't change at all (maybe 1 mph).
Cruise dropped 5-6 mph. There might have been a little more positive
control in slow flight, but that is hard to measure. I don't remember
notticing any change in takeoff performance. What it did do is increase
roll response noticeably. It was surprising on the first flight, and I
would describe it as almost twitchy, but after a few minutes I got used to
it and sort of liked it. But not enough to sacrifice the cruise for, so off
they went.
I'm told that Larry Vetterman's larger VGs are better, and that I might have
done better with the Micro's by positioning further forward than the
instructions suggested.
Andy
Builder's Bookstore
www.buildersbooks.com
Message 6
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| Subject: | Re: Vortex Generators |
--> RV-List message posted by: "Chuck Jensen" <cjensen@dts9000.com>
Andy,
It's a very interesting observation that cruise speed seemed to suffer
from application of the VGs. This is contrary to virtually every
observation, at least with canards. I would doubt that the RV is
significantly different as far as the effect of the VGs. Very
interesting. Are there other similar roconfirming observations out
there?
Chuck
> -----Original Message-----
> From: owner-rv-list-server@matronics.com [mailto:owner-rv-list-
> server@matronics.com] On Behalf Of Aircraft Technical Book Company
> Sent: Wednesday, December 21, 2005 3:29 PM
> To: rv-list@matronics.com
> Subject: Re: RV-List: Re: Vortex Generators
>
> --> RV-List message posted by: "Aircraft Technical Book Company"
> <winterland@rkymtnhi.com>
>
> I tried Micro Systems VGs on my 6A. Putting them on exactly as
directed,
> I
> didn't like them and took them off after about 10 hours.
>
> Stall speed and the feel of the break didn't change at all (maybe 1
mph).
> Cruise dropped 5-6 mph. There might have been a little more positive
> control in slow flight, but that is hard to measure. I don't remember
> notticing any change in takeoff performance. What it did do is
increase
> roll response noticeably. It was surprising on the first flight, and
I
> would describe it as almost twitchy, but after a few minutes I got
used to
> it and sort of liked it. But not enough to sacrifice the cruise for,
so
> off
> they went.
>
> I'm told that Larry Vetterman's larger VGs are better, and that I
might
> have
> done better with the Micro's by positioning further forward than the
> instructions suggested.
>
> Andy
> Builder's Bookstore
> www.buildersbooks.com
>
>
>
>
>
Message 7
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| Subject: | Air Bubbles in Fuel |
--> RV-List message posted by: "DAVID REEL" <dreel@cox.net>
Having just poured 5 gallons of fuel from a can into my wing tank, I proceeded
to pump the fuel back into the can using the boost pump. Watching the fuel flow
through the clear plexiglass of the fuel filter which is just prior to the
boost pump inlet, I observe an occasional air bubble come into the filter inlet
& get whisked out the outlet. The bubble size is small, about 1/32 inch I'd
guess. The frequency is erratic ranging from one in 20 seconds to one in a minute
or more. So, my question is could these bubbles be coming from the fuel
or do they indicate an air leak?
Dave Reel - RV8A
Message 8
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| Subject: | Re: Vortex Generators |
--> RV-List message posted by: Kevin Horton <khorton01@rogers.com>
On 21 Dec 2005, at 13:30, Jerry2DT@aol.com wrote:
> --> RV-List message posted by: Jerry2DT@aol.com
>
>
> Hi Bob,
>
> Do you have any test data you could share with us? I've tried to
> find data
> in the past on VG's, but seems to be very little.
Terry Jantzi tried Larry Vetterman's VGs on his RV-6. He temporaily
mounted a pitot boom with a swivleing pitot head to try to get more
accurate stall speeds. He found about a 3 kt reduction in stall
speed with full flap, and a five knot loss of TAS in cruise. The
stall speeds were measured at aft CG. With the VGs installed, he ran
out of aft stick before getting a stall break at forward CG. It
seems like there wasn't much of a reduction in stall speed at forward
CG.
More info at:
http://ontariorvators.org/pitot/pitot.htm
Kevin Horton RV-8 (finishing kit)
Ottawa, Canada
http://www.kilohotel.com/rv8
Message 9
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| Subject: | Re: Vortex Generators |
--> RV-List message posted by: Kevin Horton <khorton01@rogers.com>
On 21 Dec 2005, at 15:45, Chuck Jensen wrote:
> --> RV-List message posted by: "Chuck Jensen" <cjensen@dts9000.com>
>
>
> Andy,
>
> It's a very interesting observation that cruise speed seemed to suffer
> from application of the VGs. This is contrary to virtually every
> observation, at least with canards. I would doubt that the RV is
> significantly different as far as the effect of the VGs. Very
> interesting. Are there other similar roconfirming observations out
> there?
Imagine the aircraft as being stationary, with the wind moving around
it, as if it was in a wind tunnel. The air molecules that are
touching the aircraft skin have zero relative speed to the skin. The
speed of the air increases as you move away from the skin, until it
finally reaches the full velocity at some small distance from the
skin. These speed changes occur in the boundary layer. The air that
is close to the aircraft's skin is moving very slowly, and it doesn't
take much to cause it to separate from the skin. This is what
happens at the stall.
VGs work by sticking up through the boundary layer to grab the higher
velocity air that is present a little ways from the skin. The edge
of the VG generates a tiny vortex that brings higher speed air down
close to the skin. This high speed air resists separating from the
skin, so the stall is delayed until a higher angle of attack (and
hence a lower speed). VGs will cause a drag increase, as they are
sticking out into the higher speed air. They also bring higher speed
air closer to the skin.
The amount of drag will depend on the number of VGs, their height,
and the speed of the air at that location. Some aircraft only need a
small number of VGs to help sort out an airflow problem in a small
location. In this case the amount of extra drag might be difficult
to measure. And, it is theoretically possible that the new airflow
pattern downstream of the VGs might even be beneficial, so that the
drag could be reduced. This is probably the case at high angle of
attack (i.e. at an angle of attack such that the wing would have
stalled without VGs). But it isn't likely in the cruise case if the
VGs are used on the wing to reduce stall speed.
Kevin Horton RV-8 (finishing kit)
Ottawa, Canada
http://www.kilohotel.com/rv8
Message 10
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| Subject: | Bettery Revival? |
--> RV-List message posted by: REGAES@aol.com
I just returned from the airport where I found that I had left the master
"ON" and the
RB25 battery was dead. Is it possible to resuscitate this completely dead
battery
or do I need to order a new one.
Clyde Seager
RV-4 N28CS
Do Not archive
Message 11
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| Subject: | Camloc Group Buy |
--> RV-List message posted by: "" <tx_jayhawk@excite.com>
All, I posted this on the Vansairforce site, but I wanted to offer it up here for those that may not check that site. Let me know via email if ou are interested...I'll follow up with more details once I have a count. http://www.vansairforce.com/community/showthread.php?t=4671THanks,Scott7A Fuse
Message 12
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| Subject: | Re: Air Bubbles in Fuel |
--> RV-List message posted by: Fiveonepw@aol.com
In a message dated 12/21/2005 4:26:54 PM Central Standard Time, dreel@cox.net
writes:
So, my question is could these bubbles be coming from the fuel or do they
indicate an air leak?
>>>
Possibly from some trapped air pockets in high areas of fuel system? If
that's all that's getting through, I'm sure it will exit out the carb vent and
wouldn't worry about it. If real leaks are a concern, they will likely show up
when you fill the tanks full, which is the next step anyway, eh?
Mark Phillips -6A N51PW 260 hrs (and yeah, I had the clear filters in both
wingroots just because I wanted to watch for what you are now seeing plus how
much crud I'd left in the tanks! No gascolator, neither...)
Message 13
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| Subject: | Wings before engine |
--> RV-List message posted by: "DEAN PSIROPOULOS" <dean.psiropoulos@verizon.net>
I agree with Gerry, don't do it Geoff. I put my wings on my RV-6A a year
ago and it has indeed been a pain in the feet walking from the front of the
hangar (where I'm working on FWF), around the wing tips to the back of the
hangar where workbench and the tools are :-( I installed the wings before
installing the engine because I wanted to install the main landing gear and
the only way to do that permanently on an RV-6 tri-gear is with the wings on
(the main gear mounts bolt directly to the main spar in the RV-6 not the
carry through structure like the -7/8/9, simple but a hassle). I tried to
do as much airframe stuff as I could with the wings off and that included
the gear leg fairings and wheel pants. It's easy to lift the fuselage by
hand (when wings and engine are not installed) and put it on saw horses in
the level position (with the wheels off the ground) so you can install the
fairings and pants properly. This is not exactly a trivial job, you'll need
to do it sooner or later anyway, and I would be a bit nervous about jacking
the airplane and letting it sit that way for long periods with the weight of
engine and other items hanging on. And, if you can, build your panel and
wire as much of the fuse and wings as possible right now, that makes it
easier to get in and out of certain places here too. Just my experience,
good luck and happy building.
Dean Psiropoulos
RV-6A N197DM
Wiring!
---------Original message-----------------
Time: 10:21:12 AM PST US
Subject: Re: RV-List: Wings before engine?
From: Gerry Filby <gerf@gerf.com>
After that's complete you could put them on permanently if you
wanted to. But why bother ? They consume a lot shoe leather
because you have to keep on walking aaaallll the way round the
plane to pick up that tool you left on the other bench...
Message 14
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| Subject: | Re: >Re:Vortex Generators |
--> RV-List message posted by: Oldsfolks@aol.com
I really like the slow speed stability and lower stall speed with my VG's.
My 1100' grass strip requires approach between trees @ about 35' AGL , so I
can't watch airspeed there. My landing & takeoff distance is only about half
the runway now.
I haven't been able to get enough time with them for more definitive
testing. My med ran out & I have been denied a special issuance so flying is
on
hold now. My 62 hr. RV-4 sits and waits.
Bob Olds RV-4 , N1191X
A&P , EAA Tech. Counselor
Charleston,Arkansas
Real Aviators Fly Taildraggers
Message 15
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--> RV-List message posted by: "Paul Rice" <rice737@msn.com>
Hello Listers,
I am just starting to paint some of my interior parts with a HVLP spray gun
and on sometimes get more orange peel than others. Is this due to an air
issue or paint issue, ie to much or to little. Thanks for any help.
Paul Rice
RV8QB
Almost ready to install wings
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