Steve,
 I rolled out the cowl with an english wheel since those photos were
taken.
I talked with Everett Hatch about a year before his accident, and took
some
advice from him on materials for the cowl. It's .050 5000 series aluminum,
the spinner is 16" dia, the prop hub is 44" from the firewall, as opposed
to
39" for the stock RV-4, and the firewall is 1" higher, and 4"
deeper(lower)
than stock. Radiator and oil cooler are slung beneath the wing spar.

Pictured are the station buck and english wheel, and the other picture is
the first attempt at the top of the engine cowl. The later, successful top
part was made out of two halves, rather than one piece.


Brian Trubee

Brian--kudos on that cowl.  Only folks directly involved in one of those
projects knows how much is involved.   As Everett probably noted to you,
we
built an all-aluminum one for the RV-3 using multiple pieces all welded
together then worked smooth.  Took a long time.  But as you know, on a
very
tightly cowled engine the exhaust ports are potential cutting torches in
close proximity and pointed directlly at the cowl, so with a plastic cowl
its always a higher hazard. Have always been scared spitless of the lethal
potential of engine-related fires.  Other than time and complelxity to
build
the aluminum cowl, the negative surprisingly was that it came out quite a
bit heavier than a fiberglass counterpart.  How much does yours weigh with
all related hardware installed?

We flew the rotary RV-4 for years with two different types of fiberglass
cowls so thought I would try that again on the new RV-3 under construction
to save some weight.  Used the aluminum cowl as a starting point  the
current fiberglass cowl and will have to build pipe enclosure and standoff
heat shields from .016 stainless.  Another time consuming project in
itself
as the pipes snake around various bits.  You have any photos of your
cowl/spinner installed?  Did you know how to wheel and work compound curve
aluminum before starting the project?

Steve Beckham

Brian I know somebody is in the market for a cowl. Are you interested
in making another one for money?

Paul Lamar



I haven't weighed the cowl with all it's hardware, I'm going up to the
hangar today so I can do that and report back this evening. I didn't have
any experiece with english wheels, before my airplane project, but I did
spend the night at the Marriot once. ; )  This is the second aluminum cowl
I
made for this plane, I made the first about 10 years ago on an english
wheel
down in Graham, Washington. I gave that away , because I changed the
configuration of the firewall and spinner. Then I made a cowl out of
fiberglass but decided to go back to aluminum because of the exhaust  and
heat concerns you mentioned. When you welded the cowl pieces, did you use
gas or TIG welding?


I might be interested in building another cowl. Have that person get in
contact with me and I can see what they are interested in doing. Playing
with the english wheel is interesting- it's quiet and kind of relaxing.

I just got my Dynon D10 and ELT, and Ameriking 121.5, so the only  thing
left is the transponder. I've got a one page punch list of items before
the
plane will be ready for inspection.




Brian Trubee


Brian--we were in a thrash with the prototype engine at the time so one of
the guys in the shop had it welded by someone he knew and result was a mess.
It was rescued by Francis Romig, our master machinist who was a great metal
worker as well.  But took a long, long time for him to hand work it to get
in acceptable shape.  Don't know what the unknown welder used, but in-house
for aluminum we never used anything but TIG.  If you ever are in these
parts, you are welcomed to fly in and take a look at the aluminum cowl.
Where are you based now...still in Washington State?  Obviously a soft spot
in my heart for RV-4's, so would like to look over your project if and when
it is handy.

Steve Beckham