049 test stand dont's
Tim Wescott
For a motor stand I'm using a Tatone stand with a piece of 1/8" angle
iron on which the engine is bolted.
Don't do this, unless you want some practical education in resonances.
At the 'bad frequency' (which was just a bit lower than what the engine
really wanted to do) I could see the cylinder moving through a 1/4" long
arc.
Very disconcerting.
But I could damp it out by hanging on to the engine, so I verified that
it runs (and smells) normally for a little Diesel conversion, and I have
the compression and mixture at a good setting to go on a plane.
Tomorrow I go flying.
Sometime soon I go get some nice thick T-bar and make a new test stand
adapter for 049s!
--
Tim Wescott
Wescott Design Services
http://www.wescottdesign.com
Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details at http://www.wescottdesign.com/actfes/actfes.html
Martin X. Moleski, SJ
>Don't do this, unless you want some practical education in resonances.
>At the 'bad frequency' (which was just a bit lower than what the engine
>really wanted to do) I could see the cylinder moving through a 1/4" long
>arc.
>Very disconcerting. ...
Gives me the shivers just thinking about it.
Sounds like the conversion worked and you and the
engine survived the test run. All's well that
ends well!
Marty
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MJKolodziej
"Tim Wescott" <t...@seemywebsite.com> wrote in message
news:B6-dnQFFFODdNPjV...@web-ster.com...
Cool!
How did you start it? Power or fingers? Fuel tank attached or apart?
mk
Morgans
"Tim Wescott" <t...@seemywebsite.com> wrote
> For a motor stand I'm using a Tatone stand with a piece of 1/8" angle iron
> on which the engine is bolted.
>
> Don't do this, unless you want some practical education in resonances. At
> the 'bad frequency' (which was just a bit lower than what the engine
> really wanted to do) I could see the cylinder moving through a 1/4" long
> arc.
Another thing you can do, until the engine sizes get really big (big enough
to move a concrete block <g>) is to mount the stand to a piece of 2 X 8
(either using the steel between the engine mount and the wood, or not) and
mount the whole thing on a 8 X 8 X 16" concrete block.
The block adds enough mass to purty much guarantee that the resonance will
be too low to matter, and the wood helps even more to dampen out any small,
fast vibrations.
That, plus you don't need to do anything except set your block out in the
yard, and crank up the engine.
Like I said, until you go with a really big gasser, it ain't goin' nowhere!
<G>
--
Jim in NC
Tim Wescott
I'm pretty sure this resonance was the angle iron flexing in the stand,
which wouldn't change much if it were on a concrete block.
I'll know more after I get the 'right' adapter built.
Tim Wescott
got a Golden Bee right now, and will need a spacer to get the prop out
far enough to clear the cowl. So, maybe I fly Sunday.
Cox 049s without mods don't do well being started with an electric
starter. It can be done, but the prop drive and crank case are both
aluminum, so they get chewed up pretty quick. There were supposed to be
some marine engines that had bronze or brass prop drives which are
supposed to work better.
I've been thinking of taking one of my chewed-up crank cases (guess how
they got that way!) and fitting a steel collar at the end of the crank
case to run against the prop drive; dunno if I'd go to the trouble of
turning out a brass prop drive.
At any rate, this one starts with a generous prime and a few healthy
flips by hand. I had been using a chicken stick, but did you know that
rubber turns to black gunk in the presence of diesel oil and ether?
Fingers don't...
The big challenge was getting the needle and compression adjustments
sorted out the first time; now it should go without adjustment. I need
a tach, but it's turning a 7-4 prop 'good and fast' -- it sounds barely
slower than a glo 049 with a 6-4 prop, so it should pull my slightly
oversized control line job around pretty well.
Jim Chandler
Good Gawd! You mean someone actually still flies .049 Ukies? I have
done that since I was a kid. It WAS fun though.
Jim
Tim Wescott
It still is. Cheap, too, as long as the bucket-o-engines holds out.
I haven't done it for a while, so I expect to get dizzy -- this is the
driver behind the small tank, and may also lead to some BB's or bits of
Teflon in said tank until my middle ears adjust.
cavelamb himself
>>
>> Good Gawd! You mean someone actually still flies .049 Ukies? I have
>> done that since I was a kid. It WAS fun though.
>>
>
Some of us still fly free flight rubber band!
(if you want a real challenge building something)
Richard
http://groups.yahoo.com/group/Peanut_Plans/
http://groups.yahoo.com/group/dimescale/
http://groups.yahoo.com/group/ffcookup/
Morgans
"Tim Wescott" <t...@seemywebsite.com> wrote
> I'm pretty sure this resonance was the angle iron flexing in the stand,
> which wouldn't change much if it were on a concrete block.
>
> I'll know more after I get the 'right' adapter built.
Is the stand made of the said angle iron, or is the mount mounted to the
angle iron?
I pictured the angle iron mounted in direct contact to the wood, for its
whole length, and on both legs, just to give the mount some real firm
footing to mount onto. Perhaps even some construction adhesive along with
some screws, making the angle have direct contact in it's entirety.
--
Jim in NC
The Raven
About to run my Surestart engine tomorrow.
> For a motor stand I'm using a Tatone stand with a piece of 1/8" angle iron
> on which the engine is bolted.
I'm using a lump of pine that was being used to make engine mounts for a
Gremlin.
> Don't do this, unless you want some practical education in resonances. At
> the 'bad frequency' (which was just a bit lower than what the engine
> really wanted to do) I could see the cylinder moving through a 1/4" long
> arc.
>
> Very disconcerting.
Probably not good for the mount or the engine but it would take some
experimentation to prove it.
> But I could damp it out by hanging on to the engine, so I verified that it
> runs (and smells) normally for a little Diesel conversion, and I have the
> compression and mixture at a good setting to go on a plane.
Mines just a new old stock 049, my very first 049.
> Tomorrow I go flying.
Same here but not with this engine. My trainer is getting some hasty repairs
to make it look airworthy....people want to ban it but it is simply
unbreakable.
JR North
2' high wooden step ladder and some custom milled adjustable engine
mount rails. The .91 could fly the ladder if I let it. The ladder does
a good job of damping harmonics.
JR
Dweller in the cekllar
who had a large collection od Cox planes in his yout.
On Fri, 27 Jun 2008 20:00:23 -0700, Tim Wescott <t...@seemywebsite.com>
wrote:
>Got a Cox reed valve 049 engine going today, with a Davis head.
>
>For a motor stand I'm using a Tatone stand with a piece of 1/8" angle
>iron on which the engine is bolted.
>
>Don't do this, unless you want some practical education in resonances.
>At the 'bad frequency' (which was just a bit lower than what the engine
>really wanted to do) I could see the cylinder moving through a 1/4" long
>arc.
>
>Very disconcerting.
>
>But I could damp it out by hanging on to the engine, so I verified that
>it runs (and smells) normally for a little Diesel conversion, and I have
>the compression and mixture at a good setting to go on a plane.
>
>Tomorrow I go flying.
>
>Sometime soon I go get some nice thick T-bar and make a new test stand
>adapter for 049s!
--------------------------------------------------------------
Home Page: http://www.seanet.com/~jasonrnorth
If you're not the lead dog, the view never changes
Doubt yourself, and the real world will eat you alive
The world doesn't revolve around you, it revolves around me
No skeletons in the closet; just decomposing corpses
--------------------------------------------------------------
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--------------------------------------------------------------
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Tim Wescott
The Tatone test stand is for 'conventional' engines with mounting ears
on the side of the crank case. I have the 049 engine bolted to a piece
of angle iron, and the angle iron is in the Tatone mount, clamped in
place of the conventional engine mounting ears.
Morgans
"Tim Wescott" <t...@seemywebsite.com> wrote
> The Tatone test stand is for 'conventional' engines with mounting ears on
> the side of the crank case. I have the 049 engine bolted to a piece of
> angle iron, and the angle iron is in the Tatone mount, clamped in place of
> the conventional engine mounting ears.
Ahhh, I see.
Yep. Fatter steel is needed! <g>
--
Jim in NC
Jim Chandler
Or you could use the ballet dancer/ice skaters trick and keep your head
in one spot for a quarter turn or so then snap it around to catch up
with where everything is then do it all over again. Gives the ears a
chance to stay equalized because the fast head movement then stop is
faster than the ears can be upset.
Jim
Jim Chandler
I've got an R/C glider out in my shop (in the rafters) that I've been
"working" on for over eight years. The fuselage is done and the wings
are 3/4 covered. I'll have to buy a new set of batteries and a charger
for the radio before I can do anything with it. I tried to charge a
Heathkit R/C battery pack with the Toshiba charger. Didn't work. Took
the charger out but good. One of these days....
Jim
Flash
"Jim Chandler" <n4...@gte.net> wrote in message
news:8Bz9k.51$Ae3.12@trnddc05...
Jim, I don't know what kind of vertigo those dancers and skaters have, but
that did not work with my variety, for sure!
I quit U-control in the 80's because. (Hmmm... I wonder? Time has
passed, and the hobby shop is only 5 minutes away and an .049 would be a
cheap experiment)
Flash
Tim Wescott
subsequent flights went well.
My 15-year old soloed! His first flight ended in what I thought would
be a splintering crash, but which he curved into a gentle
'stop-the-prop' landing. After that he did just fine.
Boo
> that did not work with my variety, for sure!
>
> I quit U-control in the 80's because. (Hmmm... I wonder? Time has
> passed, and the hobby shop is only 5 minutes away and an .049 would be a
> cheap experiment)
Learn to fly figure 8's and your probkems are over. Maybe there's a CL
simulator available somewhere that would get you that far ?
--
Boo
Gunner Asch
Anyone need one..Ive got what appears to be a new in box 12vt model
engine starter.
Gunner, with a half completed glider hanging in the reloading
shop....sigh
at yoyodyne they were all veterans of the psychic wars
exiled from the eighth dimension where the winds of limbo roar"
mariposa rand mair theal
Jim Chandler
The theory is that if you can stay focused on a point longer then
acquire another focus point your senses aren't as confused. Spatial
disorientation from spinning is different that vertigo.
Jim
Jim Chandler
I just remembered, I have an .049 out in the shop somewhere, along with
a couple fo other glo engines. Maybe I should drag them out and do
something with them (as if I don't already have enough to do).
Jim
Jim Chandler
What kind of half-completed glider do you have, Gunner? My
half-completed glider is a "Spirit", and I think that's what I'm waiting
for to move me to complete it. :-)
Jim
Gunner Asch
fiberglass fusalage, plywood covered foam wings, with about a 72"
wingspan. A good friend gave it to me, as Ive always liked gliders,
and he was an engine guy. I bought all the servos, a controller (have
to go check what kind...futaba pwm rings a bell...and we started
building two planes. The idea was the bird he was building was going
to be the tow plane for launching my glider. I even designed a release
mechanism...5 channel radio irrc
Then he grabbed his chest and dropped dead.
I kinda lost interest at that point..and its been hanging up there,
with the wings not yet covered for about 10 yrs now.
I live in the rolling foothills , with great thermals and good slopes,
and many model airplane events are held here, or used to be..the free
flights being one. Its about 105F on average here in the summer, and
wth the wide open spaces, and great thermals..its a natural for
gliders.
someday ill get around to finishing it. Id like to. But..Ive got two
motorcycles Ive not ridden for at least 8 yrs, and a 22' sailboat
thats not been in the water for at least that long and the Hobi
16..even longer.....working away from home for weeks at a time...when
i get home...too much to do, not enough free time.
Gunner
Morgans
"Jim Chandler" <n4...@gte.net> wrote
> The theory is that if you can stay focused on a point longer then acquire
> another focus point your senses aren't as confused. Spatial
> disorientation from spinning is different that vertigo.
I can't believe nobody has mentioned why doing ballet (or ice skaters)
"turn and stop" head movements would be a VERY bad idea.
I would think keeping your eyes focused on your plane _all_ the way around
the circle would be a very GOOD idea! <g>
Unless, of course, you LIKE repairing crashed airplanes! </:~o)
--
Jim in NC
Jim Chandler
You sound like me with all the projects, and I don't even work away from
home. Good luck with it. I can imagine that your friend dropping dead
would sort of take away from the enthusiasm. If you ever get to working
on it again, just think of it as a memorial to him.
Jim
iceri...@gmail.com
wrote:
One of the quickest ways to nail down control line aerobatics is to
use a two line kite. The local grocery store even has a nylon kite
with fiberglas rods for $9.99! First learn to fly it with the two
handles provided then use a dowel to make a control "handle" with the
same spacing that you keep your hands apart when flying the kite.
Then just hold the dowel with one hand and start flying with the dowel
held upright. You have to re-identify right and left as up and down
but without too much problem you will be doing figure 8's and loops in
a short time. On really windy days that are too much for CL flying I
pull the kite out and have a lot of fun.
See ya in the circle,
Bob Furr
Gunner Asch
Ayup...the memorial idea is why I simply didnt give it away to
someone. I owe it to him to get it aloft and land it safely at least
once...though he was known for his spectacular occasional 'lawn darts'
Gunner
"The American people will never knowingly adopt socialism, but under the
name of liberalism they will adopt every fragment of the socialist program
until one day America will be a socialist nation without ever knowing how it
happened." -- Norman Thomas, American socialist
Don Stauffer in Minnesota
> Got a Cox reed valve 049 engine going today, with a Davis head.
>
> iron on which the engine is bolted.
>
> Don't do this, unless you want some practical education in resonances.
> At the 'bad frequency' (which was just a bit lower than what the engine
> really wanted to do) I could see the cylinder moving through a 1/4" long
> arc.
>
>
> But I could damp it out by hanging on to the engine, so I verified that
> it runs (and smells) normally for a little Diesel conversion, and I have
> the compression and mixture at a good setting to go on a plane.
>
> Tomorrow I go flying.
>
> Sometime soon I go get some nice thick T-bar and make a new test stand
> adapter for 049s!
>
> --
>
> Tim Wescott
>
> Do you need to implement control loops in software?
> "Applied Control Theory for Embedded Systems" gives you just what it says.
> See details athttp://www.wescottdesign.com/actfes/actfes.html
Okay, taking this thread a bit off-topic, can one still buy a half A
engine? I have a project in mind, but understand you cannot buy half A
engines anymore. The only one I have left is a Cub, and that is
dedicated to a vintage Ukie kit- do not want to use it on a new RC
project.
MJKolodziej
http://www3.towerhobbies.com/cgi-bin/wti0093p?&C=GCA&P=7
for RC
you could wire the throttle open
mk
"Don Stauffer in Minnesota" <stau...@usfamily.net> wrote in message
news:c6edecad-4519-4bf6...@26g2000hsk.googlegroups.com...
Tim Wescott
As pointed out, Brodak sells 'em.
OK engines makes a reed valve engine -- search for "OK Engines" on the web.
As of a year or two ago Norvel made a sport and a high performance
version, both ABC, each available as both RC and CL (I actually
considered buying a Norvel 061 for this plane, but no one had it locally).
Dr. Diesel has British 1/2A diesel engines.
Rummage sales and/or inquiries at your local flying club may find enough
Cox engines that your bucket-o-engines will be bigger than mine. Just
let all your flying buddies know you'll take old Cox engines off their
hands, and you'll be getting them long after you say "stop". You can
get all the rebuild parts for Cox engines from various sources -- I use
the nice teflon pieces available from Davis Diesel, plus an 'O' ring for
the venturi-to-backplate seal made by cutting off a ring from a bit of
silicon tubing with a Very Sharp xacto knife.
misc_poster
Okay, taking this thread a bit off-topic, can one still buy a half A
engine? I have a project in mind, but understand you cannot buy half A
engines anymore. The only one I have left is a Cub, and that is
dedicated to a vintage Ukie kit- do not want to use it on a new RC
project.
Then there's this: http://www.coxmodels.com/prodinfo.asp?number=008901
2fast
and another made by Thundertigre. The only high performance engines left
out there for purchase are the GZ (around $100.00) and the Fora and the
Cyclone for closer to $200.00. There are no Cox or Norvel being produced
now but you can still find a few on the bay. If it were up to me I'd go
with the GZ.
** Posted from http://www.teranews.com **