From: fisher@kay.enet.dec.com (kay::fisher)
Subject: Re: RC submarines
Organization: Digital Equipment Corporation
Date: Sat, 5 Sep 1992 05:17:42 GMT
X-Posted-Via: NEWS-NOTES gateway (a hack!)

Since there seems to have been a bit of interest lately in RC submarines
I thought I would share with you my trip report from July.  This
is an edited version of a post on the Digital Equipment Corporation
RC notes file.  For those interested the Gremlin mentioned is an RC
Combat Flying wing.  Foam wing with a PVC down spout fuselage.  There
should be an construction article in RCM "real soon now".  They
fly great - rock stable.

Bye          --+--
Kay R. Fisher  |
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KAY::FISHER "The higher, the fewer"                 216 lines  13-JUL-1992 09:49
                      -< RC Submarines and a new Gremlin >-
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Saturday I attended the RC Submarine Regatta at the US Sub Base in
Groton CT.

Awesome.

Many many RC submarines of various sizes.
Several methods were used to submerge.

    1.  Don't - there was at lease one that never submerged.  Just run
        on the surface all the time.  

    2.  Blow ballast with propel.

    3.  Blow ballast with CO2.

    4.  Pump ballast in and out.  This requires the periscope to
        be an air line above the water line.  You might think that
        once submerged this wouldn't work - however one has only
        to pitch up the bow planes and drive to the surface to bring
        the periscope up and then start the pump.  Actually works
        pretty good.
    
    5.  Piston chamber with air on one side in a closed chamber and
        water on the other side.  This is new to the group and I'm not
        sure if I actually saw any using this method.

Scale

    Most boats were copies if real submarines but there were 3 Robbe
    non-scale kits - they worked pretty good and it looks like a 
    good way to start in this hobby if you aren't obsessed with scale.

    There was one Nautilus.  Not modeled after the real Nautilus but
    the Nautilus from Jules Vern.  Looked great.

    There was one Seaview - from the television show.  So here is a
    trivia question.  Anybody remember the name of TV show.  I remember
    Admiral Nelson and Chief Kowalski(sp) was it.  Anyone remember
    more crew members.  It always amazed me then a wall of wires would 
    burst into flames.  After they put out the fire the Admiral would
    ask the Chief how long it would take to repair it.  Usually it
    only took a couple of hours.  I wish field service would hire this
    Chief :-)

    The rest of the boats were scale models of American, German, and
    Russian submarines.  The best sailing one was a Russian Akula(sp)
    sub.  

Vendors

    There were several vendors there.  Two selling hulls.  One was 
    vacuum formed plastic and cheap ($33-50).  One was glass and
    expensive ($250-400).  The experts said the plastic was only good
    for static although the vendor was saying otherwise.  None of the
    boats that went in the water were made from the plastic kits but
    there were another 20 or so boats that were Static only on display.

    Several boats were constructed from "32 Parallel" kits and some
    were purchased in the UK and Germany.

    There was a raffle.  I didn't win.  1st prize was a 32 Parallel
    kit - probably a $200-300 value.  2nd prize was an Airtronics
    radio system.  3rd prize was a Combat Models kit (plastic vacuform).

    There were representatives there (crew men) from two active submarines
    ship stores.  So you could buy hats and T-shirts and sweat shirts
    and do dads from the USS Dallas and USS Pargo.  Anybody remember
    the hunt for Red October?

    There were two vendors showing precision tools.  There were 3 vendors
    selling plastic model kits and books.  The books were neat and up until
    now I would say I've read every paperback book on WWII submarines.  But
    at this event they had many many books I had never seen before.  I was
    overwhelmed.  I didn't purchase any.  One new book was on sale and
    the author (a retired Admiral) was there signing it.

    I met one German fellow who had served on subs during the war.
    
    One fellow was displaying and selling torpedoes.  They were awesome.
    Electric powered and had contra rotation screws.  The screws were
    only about 1/4" in diameter.

Facility

    This was in a lake (pond) on the sub base that was used for swimming.  It
    was a very nice little (man made I assume) lake with a diving raft
    and platform on the deep end and nice sandy beach around.  There was
    two life guards on duty and nobody was allowed to swim because of
    regatta.  Several folks showed up to swim are were upset that they
    couldn't.

    There was a set of picnic tables set up under a miranda(sp) where the
    vendors displayed their goods and the skippers assembled and adjusted
    and displayed their subs.  

    There was a nice judging stand set up high above the pond and a course
    was set up.  Basically each pilot had to navigate thru a set of markers
    and submerge once and dock once.

    I understand that the docking sequence is where they always fired
    torpedoes - but I never saw one.

Observations

    I wouldn't consider building one without first attending an event
    like this and joining their group "Subcommittee" and reading their
    newsletter.  

    It costs about $600 for a good modest sub.

    It costs as many hours as a scale plane.

    Some (maybe all) seem to be pitch unstable when submerged.  Although
    I didn't see any porpoise I understand it is a major problem and
    some subs have pitch stabilization devices in them.  Most used gyros.
    One fellow was using a pendulum device with hall effect devices.

    There is an optimal size.  I saw several huge subs - 8-11 feet long.
    They couldn't turn in a reasonable space and required 4 men to get
    them in and out of a car.  Remember to submerge it has to weigh the
    same as if it was a jug completely filled with water.  The motor and 
    batteries and receiver and ballast system can't be shrunk easily and 
    the really small subs were also hard to work on.  The optimal size 
    seems to be about 4-5 feet.  Take a look at your desk - it's 5 feet 
    long.

    Most (not all) maneuver better submerged than surfaced.  Most (maybe all)
    are faster submerged than surfaced.

    The course looked easy to me but only one guy got a perfect score.

    Like all other types of RCers, the guys were very friendly and more
    then willing to share info and help you get started.

    My wife Pat went with me and was perfectly happy to enjoy the sun and 
    relax next to the waters edge.  Unlike some glider contests she did not
    feel at all in danger from accident or pilot (skipper) error.

Conclusion

    I'd like to go back next year and get enough information to be dangerous.
    Then I'd like to build one for the year after that.  My wife was willing 
    to let me purchase on of the vacuform kits knowing that it was only the
    tip of the iceberg in expense - but I resisted.  I'm holding out for a 
    really good one - or a scratch built one.

============================================================================

Well that was Saturday.

We left Groton CT and drove to Sturbridge MA.  

Sunday we drive to the Divot Diggers field in Ware MA and...

==============================================================================

I was Jim Reith's guest at the field and the goal was go get enough stick
time on his Gremlin with the buddy box so that I could safely fly my own.

Jim took his Gremlin up (it had not yet been flown) and it was a real hand
full for a flight or two before he got it trimmed out and got the motor
running reliably.  But eventually it smoothed out and he let me fiddle
the sticks.  The rolls were pretty aggressive for me so he landed and
toned it down some more.  Then we tried again and I got a little used
to it.  Then Jim let his son Jimmy get some stick time on the buddy box.
Wow - talk about stressing family relations.  I'll let Jim describe
it from his view.  Another gremlin went up at the same time with a streamer
on and Jimmy was trying to cut it while Jim thought he was out of control!

Anyway eventually I cranked up my Gremlin and threw it for Jim.  First
flight was up about 50 feet and the engine died and dead sticked in.

Even tho it was a short flight Jim was sure it needed lots of up trim.
So we programmed some in and leaned the engine a bit and the next throw
was a complete flight.  Jim trimmed it and I finished the flight on low 
rates.  

Also we had to throttle back early in the flight because of flutter.

I had scotch tape hinge (hey - I was in a hurry).

So between flights I had to fix my hinge rip with some Mylar tape that
Jim had.  Also I lowered the throws more.  The next flight (was it the 
last?) Jim thru it and I flew the whole flight.  No flutter but I never
flew it very fast.  I lost orientation 2 or 3 times during the flight.

I kinda think with the long nose and the wing so far back that in the
air it looks kinda like a Wart Hog.

I'm not used to it yet and I'd be dead meat in combat but I am ready
to fly on my own thanks to Jim and his club.

Gotta re-do the hinges and go get some more stick time.

This is the first glow powered plane I've flown in about two years.
I've had a couple of under powered electrics in between - but nothing
that required a flight box and starter etc.

Oh yes - the mylar held up fine.

The OS-25 FP is awesome.

I did pull up for a wing over or stall turn several times and slam the left 
stick over for rudder before I realized I had no rudder.

Now what is it I'm suppose to do if I accidentally get into a flat spin
with this thing?

Pass the streamer and call me Target "K".

Bye          --+--
Kay R. Fisher  |
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