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Model Forum / Radio Controlled / Water Models / February 2005



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Request for Assist - Aero-/Hydro-dynamic analysis - Hydrofoil

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abracadabra - 19 Feb 2005 20:50 GMT
I would like to build a 1/64 (preferred) or 1/48 scale model of

   FHE-400 HMCS Bras d'Or hydrofoil experimental ship.

As was the case with the original, whereby the foil system was designed by
deHavilland Aircraft Company of Canada, I am approaching the "air" category
to find someone who can assist PRIMARILY with the analysis of the
hydrofoil from a standpoint of

   1) angle of attack
   2) sizing of chord
   3) lift estimates
   4) determination of forward speed sufficient to provide adequate lift
for
       a realistic-looking scaled motion.

For those who are not familiar, the Bras d'Or had a canard wing arrangement
with 90% of lift from the main rear foil and 10% from the bow canard foil
which was also the rudder.

I am approaching this project in a number of phases as follows:

   I) analysis of scaled dynamics and feasibility of proportional foil
structure
       - challenge:    sizing foil so that inherent surface-piercing
lifting effects assist with stabilization
       - challenge:    sizing lift so that main-foil tip stabilizing fins
remain submerged for effect
       - plan start:    May 2005
       - plan end:    July 2005

       => SCOPE of current request is limited to Phase I only.

   II) design of foil control systems (servo-system I)
       - challenge:    coordinate bow foil turning with main foil
stabilizer fins
       - challenge:    eliminate need for tilting bow-foil during take-off
transition
       - plan start:    July 2005
       - plan end:    August 2005

   III design of propulsion system (servo-system II)
       - challenge:    design foil-mounted propeller system (if possible)
       - challenge:    design single propulsion system (valid for both
hull-borne and foil-borne modes)
       - plan start:    July 2005
       - plan end:    August 2005

   IV) building disposable experimental hull for control and dynamics
design confirmation/tuning of re-usable main/canard foil systems
       - plan start:    August 2005
       - plan end:    October 2005

   V) Iterations of control systems design
       - challenge:    self-stabilizing for rolling, even (tricky part)
during inclined turns
       - plan start:    October 2005
       - plan end:    April 2006

   VI) building realistic scaled hull, re-using above working foil system
       - plan start:    April 2006
       - plan end:    August 2006

   VII) building scaled stand-off docking facilities (as originally planned
by RCN)
       - challenge:    keeping concept of electro-magnetic clamps
sufficiently simple, compact and light-weight
       - challenge:    mechanizing lifting/pivoting of gantries (docking
clamps)
       - plan start:    August 2006
       - plan end:    November 2006

Phases (I) thru (V) are go/no-go phases depending on confirmed feasibility
(within my limited skills).

Any individuals who wish to put their name forward for this project will be
more than welcome to participate.

In the long run, it would be nice to have a number of individuals, each with
their own model ship,
so as to create the fleet that never was !!!!

       (please allow me my momentary insanity and delusions of grandeur)

Thank you in advance for your comments.

Eric
Bill Fulmer - 19 Feb 2005 21:39 GMT
You have GOT to be an engineer.........................<G>

> I would like to build a 1/64 (preferred) or 1/48 scale model of
>
[quoted text clipped - 83 lines]
>
> Eric
abracadabra - 20 Feb 2005 17:28 GMT
Owwwwww !!!!!!  That hurts !

Guilty.

Eric
abracadabra - 24 Feb 2005 19:24 GMT
I'm a hobbyist at heart whose allowed life to interfere with his mania.

When I was a kid, model building mania took hold of my mental
capacities ages 8-16.

   - my Meccano (metal) sets kept me busy for about 4 years
   - built 2 balsa-wood and tissue airplanes, both rubber-band driven.
   - built lots of plastic models, mostly airplanes, some tanks and cars
   - me and my GI Joe had a lot of fun for about 2 years
       ( sewed his clothes etc. myself)
   - I was a Cub Scout for 2 years when the local troop disbanded.
   - I was a Navy League Cadet for 2 years when the local organization
       collapsed (closest I got to the real-ship camp that was cancelled).

Since then it's been focus on school and work, with a little of other
things.

Eric
abracadabra - 21 Feb 2005 06:51 GMT
Please extend some slack in my direction.

1) I know >> 0 << about RC
2) I know >> 0 << about floating boat modelling

I am going stir crazy and need a hobby.

I figured that this project should either do the trick
   OR  it will stir up my brains and make me crazy.

Come to think of it, both are desirable outcomes !   :-))

Eric

> You have GOT to be an engineer.........................<G>
Keith Schiffner - 21 Feb 2005 15:08 GMT
"abracadabra"
SNIP
> I am going stir crazy and need a hobby.
>
[quoted text clipped - 7 lines]
>
> Eric

One thing to remember when you model this. While
the size of the model is different from the
original the molecules that interact with the
lifting surfaces are STILL the same. When someone
finally figures out how to either scale them down
things will get interesting.

I know >>0<< Engineering

I still use my thumb for that and beef it up
anyway. ;^)
Signature

Keith Schiffner
Assistant to the Assistant Undersecretary of the
Ministry of Silly Walks.
"terrorist organization" is a redundancy

Doug McLaren - 21 Feb 2005 16:46 GMT
| One thing to remember when you model this. While the size of the
| model is different from the original the molecules that interact
| with the lifting surfaces are STILL the same.

Even so, aerodynamics (and yes, the _same_ rules do apply to things in
the water too) are reasonably well understood.  His airfoil
(hydrofoil?)  will have a different Reynolds number, but the
differences that this creates should be fairly well understood.

As for the earlier post where it says that the original poster knows
>0< about R/C ... might I suggest learning a bit about R/C first?
Make a simpler boat first, You (the original poster) might also want
to try a plane or two as well, since you're dealing with a lot of
aerodynamics here.  (But know that you can't legally use the same
transmitters and receivers for both plane and boat unless they're on
the 27 or 50 mHz bands.)

It's a great hobby, and it sounds like you might have a great time
with it, and it might have a great time with you.  I'd hate to see you
get frustrated with it because your first project is a bit overly
ambitious.  Get your feet wet with something simpler.

| When someone finally figures out how to either scale them down
| things will get interesting.

Don't they just have to go into a quantum singularity and then come
back out without retracting their exact path?  At least that's what I
recall seeing on Deep Space 9 -- though I'm suprised that they didn't
have to reconfigure the deflector dish to emit a beam of positively
charged chronoton particles into a static warp bubble too ...

Signature

Doug McLaren, dougmc@frenzy.com
"We are ready for any unforeseen event that may or may not occur."  --Quayle

Keith Schiffner - 23 Feb 2005 01:47 GMT
"Doug McLaren"
SNIP
What he said... or simple yep that sounds right to
me. I use my thumb to measure entirely too much.

> Don't they just have to go into a quantum
> singularity and then come
[quoted text clipped - 6 lines]
> charged chronoton particles into a static warp
> bubble too ...

Oh sure do it the HARD way! As for me I merely
take an improbability computer give a nice warm
cuppa' and wait for the results. 8^)
Signature

Keith Schiffner
Assistant to the Assistant Undersecretary of the
Ministry of Silly Walks.
"terrorist organization" is a redundancy

abracadabra - 24 Feb 2005 18:47 GMT
> You (the original poster) might also want
> to try a plane or two as well, since you're dealing with a lot of
> aerodynamics here.  (But know that you can't legally use the same
> transmitters and receivers for both plane and boat unless they're on
> the 27 or 50 mHz bands.)

Excellent insight!  Thank you,

Eric
abracadabra - 24 Feb 2005 19:02 GMT
> As for the earlier post where it says that the original poster knows
> >0< about R/C ... might I suggest learning a bit about R/C first?
> Make a simpler boat first,

...<SNIP>...

> It's a great hobby, and it sounds like you might have a great time
> with it, and it might have a great time with you.  I'd hate to see you
> get frustrated with it because your first project is a bit overly
> ambitious.  Get your feet wet with something simpler.

I have been trying to pick a deep V hull pre-built, ready-to-use model
as my first entry into this.

I viewed this as the test-bed that might be retro-fitted with test foils for
exploration/confirmation of static/dynamic analysis.

Are there any brands that hobbyist/amateurs (aficionados of sport)
find
   - fragile
   - temperamental
   - frustrating
in other words, brands to avoid ?

Could you qualify your comments for each of the following categories ?
   [1] boat brands

Thank you,

Eric
abracadabra - 24 Feb 2005 19:02 GMT
> As for the earlier post where it says that the original poster knows
> It's a great hobby, and it sounds like you might have a great time
> with it, and it might have a great time with you.  I'd hate to see you
> get frustrated with it because your first project is a bit overly
> ambitious.  Get your feet wet with something simpler.

Are there any brands that hobbyist/amateurs (aficionados of sport)
find
   - fragile
   - temperamental
   - frustrating
in other words, brands to avoid ?

Could you qualify your comments for each of the following categories ?
   [1] RC control brands
   [2] RC servos
   [3] electric motors
   [4] battery/charger systems

Thank you,

Eric
Doug McLaren - 25 Feb 2005 16:49 GMT
| > As for the earlier post where it says that the original poster knows
| > It's a great hobby, and it sounds like you might have a great time
[quoted text clipped - 8 lines]
|     - frustrating
| in other words, brands to avoid ?

As for radio equipment goes, all of the big manufacturers make good
stuff -- Futaba, JR, Hitec, Airtronics.  Hitec is a tad cheaper, but
the quality is similar all around.

As for motors, I don't really do boats -- I do planes -- so what you'd
use may be different than my experience.

But with planes, motors, even the good ones, don't cost too much
compared to the rest of your eqipment.  It's the speed controls and
batteries that really suck up your money.  Brushed motors wear out (on
the better ones, you can replace the brushes), brushless motors seem
to last forever, are more efficient and cost more.

For chargers, I don't know what your needs are, but I'm very fond of
my GP Triton charger.  It's not the best, but it does everything, and
the performance/price ratio is possibly the highest out there.  It'll
probably do whatever you need it to do, but if you have really large
batteries or lots of them, it might not do it as fast as you'd prefer.

| Could you qualify your comments for each of the following categories ?
|     [1] RC control brands
|     [2] RC servos
|     [3] electric motors
|     [4] battery/charger systems
Signature

Doug McLaren, dougmc@frenzy.com
Trying is the first step toward failure. - Homer Simpson

abracadabra - 24 Feb 2005 19:29 GMT
> Don't they just have to go into a quantum singularity and then come
> back out without retracting their exact path?  At least that's what I
> recall seeing on Deep Space 9 -- though I'm surprised that they didn't
> have to reconfigure the deflector dish to emit a beam of positively
> charged chronoton particles into a static warp bubble too ...

Sounds like you're using the deflector dish to deflect our attention
towards your other passion, Trekker Brotherhood !

Eric
 
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