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Old Oct 30, 2003, 07:01 PM
Ron
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Build it light! Build it true! Building tips?

We all know that building light results in a lighter all-up weight, lower
wing loading, and happier flying.
Getting your wing straight and true, getting the tailfeathers on square and
aligned, all make for sweeter flying planes.

Back when I first started modeling, I built from scratch mostly, and it was
a case of carefully selecting your wood, not gooping on too much Ambroid,
and CAREFUL with that HEAVY epoxy!

I know there are a lot of folks who still build from scratch, but in a LOT
of cases today, if people are building at all, it's likely from a kit. Less
choice of your wood grade, if any at all.

What are people's tips for building light, and true?

Ron


Old Oct 30, 2003, 07:01 PM
Dr1Driver
Guest
n/a Posts
Re: Build it light! Build it true! Building tips?

>What are people's tips for building light, and true?

Use ACCURATE measuring devices. Metal etched rulers and scales. Even
micrometers and calipers. LEARN how to read these devices. Hold your eye
directly over the top of the device to prevent angle inaccuracy. Hold the
device flat agasint the item being measured. Use a 0.5mm mechanical pencil to
mark lines. Use accurate angles, protractors and squares, clamps and rubber
bands to hold pieces in alignment while glueing.

Use only enough glue to do the job. Make the joint mechanically tight so less
glue will be required. Do not use epoxy for 99.9% of your joints. I've built
8' giant scale models with only CA. Even CA is heavy, use it sparingly.

Most kits are drastically overengineered. If it looks heavy, it is. Some
balsa is heavier than similar plywood, don't be afraid to substitute.

Finishing is heavy, use only enough paint or dope to cover.

Look at sailplanes, indoor models, and the NCFFA site, those guys can build
LIGHT.

That's all for now...


Dr.1 Driver
"There's a Hun in the sun!"
Old Oct 30, 2003, 07:01 PM
Six_O'Clock_High
Guest
n/a Posts
Re: Build it light! Build it true! Building tips?


"Ron" <a@b.c> wrote in message news:bOydnbgffb957zyiRVn-gA@comcast.com...
> We all know that building light results in a lighter all-up weight, lower
> wing loading, and happier flying.
> Getting your wing straight and true, getting the tailfeathers on square

and
> aligned, all make for sweeter flying planes.
>
> Back when I first started modeling, I built from scratch mostly, and it

was
> a case of carefully selecting your wood, not gooping on too much Ambroid,
> and CAREFUL with that HEAVY epoxy!
>
> I know there are a lot of folks who still build from scratch, but in a LOT
> of cases today, if people are building at all, it's likely from a kit.

Less
> choice of your wood grade, if any at all.
>
> What are people's tips for building light, and true?
>
> Ron
>
>


I use Titebond II as my gluing agent. It releases water vapor as it cures.

I try to make all my joints mechanically correct BEFORE adding glue to hold
them in place. That reduces the amount of glue being used to a minimum. In
addition, I frequently will wipe off obvious excess.

I block everything being glued for 12 to 24 hours - that helps keep it
straight.


--
Jim Branaum
AMA 1428

Six_O'clock_High
Target_Lock@Guns.com


Old Oct 30, 2003, 07:01 PM
Paul McIntosh
Guest
n/a Posts
Re: Build it light! Build it true! Building tips?

Pretty much the same things are true today. Select your wood carefully,
don't overdo the glue and build on a good, flat surface.

I haven't built a kit in many years. I have designed and built pretty much
everything I flew in the last 10 years.

--
Paul McIntosh
Desert Sky Model Aviation
http://fly.mcintoshcentral.com
"Ron" <a@b.c> wrote in message news:bOydnbgffb957zyiRVn-gA@comcast.com...
> We all know that building light results in a lighter all-up weight, lower
> wing loading, and happier flying.
> Getting your wing straight and true, getting the tailfeathers on square

and
> aligned, all make for sweeter flying planes.
>
> Back when I first started modeling, I built from scratch mostly, and it

was
> a case of carefully selecting your wood, not gooping on too much Ambroid,
> and CAREFUL with that HEAVY epoxy!
>
> I know there are a lot of folks who still build from scratch, but in a LOT
> of cases today, if people are building at all, it's likely from a kit.

Less
> choice of your wood grade, if any at all.
>
> What are people's tips for building light, and true?
>
> Ron
>
>



Old Oct 30, 2003, 07:01 PM
Fred McClellan
Guest
n/a Posts
Re: Build it light! Build it true! Building tips?

On Thu, 30 Oct 2003 14:22:01 -0600, "Ron" <a@b.c> wrote:

<SNIP>
>
>What are people's tips for building light, and true?
>


First tip : stop struggling over an extra 1/10 gram here and there.
You'll have more hair when the model is flying, and you need the extra
sun screen anyway.

On just about any size powered model a few grams weight savings won't
arbitrarily make the model fly better, and in fact it may make the
model fly worse.

I won't do the full $0.50 lecture on why, but you can find out for
yourself.

On your next film-covered-open-bay-wing model, build two wings.

Build one wing by the book, and build the second wing sheeted with
balsa and then cover it with film.

When you're all done and have collected two dozen flights on each
wing, throw out the wing you don't like to fly.

I'd bet real money you'll likely keep the sheeted version.

Not all added weight is a 'penalty'. Some specific kinds of extra
weight can actually make a given model fly _better_, not worse.
Cheers,
Fred McClellan
the dash plumber at mindspring dot com
Old Oct 30, 2003, 07:01 PM
Philip Rawson
Guest
n/a Posts
Re: Build it light! Build it true! Building tips?

Lightness...

When you see a stock of good balsa, buy it... keep lots in stock to select
from

After designing your structure, half the thickness of the bits of wood
you've specified

Use as little ply as possible

Use as little sheet wood as possible

Go and see my building diary on my website

Use built up structures wherever possible

Straightness...

Build on a granite worktop

Select straight wood, or if it needs to be bent, steam it

Never force any joint, and where possible, pre-bend sheeting

I'll repeat, 'cos it's important... never force any joint

--
Philip Rawson

www.flymodels.co.uk

"Ron" <a@b.c> wrote in message news:bOydnbgffb957zyiRVn-gA@comcast.com...
> We all know that building light results in a lighter all-up weight, lower
> wing loading, and happier flying.
> Getting your wing straight and true, getting the tailfeathers on square

and
> aligned, all make for sweeter flying planes.
>
> Back when I first started modeling, I built from scratch mostly, and it

was
> a case of carefully selecting your wood, not gooping on too much Ambroid,
> and CAREFUL with that HEAVY epoxy!
>
> I know there are a lot of folks who still build from scratch, but in a LOT
> of cases today, if people are building at all, it's likely from a kit.

Less
> choice of your wood grade, if any at all.
>
> What are people's tips for building light, and true?
>
> Ron
>
>



Old Oct 31, 2003, 04:00 AM
S. Boucher
Guest
n/a Posts
Re: Build it light! Build it true! Building tips?

Light?????? True??????????

Sounds like the makings of a scrap pile-o-balsa and covering to me.
Build it HEAVY and STRONG! There is no such thing as too much glue.
If there is any glue left at the end of your project it's because
you haven't reinforced it enough.
So what if that .20 sized craft needs a .60 to get off the ground,
that's why they make BIG engines.
If my plane hits the ground, I want the earth to shudder before I
backhoe it out and restart it.
As for building "true", what do you think the "TRIMS" are for?????
So what if it takes 50% up elevator and full right aileron to keep
her in the air, It's flying aint it????????

This is NOT really my opinion, but makes for some interesting reading
huh? ;-)
Steve


Ron wrote:


> What are people's tips for building light, and true?
>
> Ron


Old Oct 31, 2003, 04:00 AM
Dr1Driver
Guest
n/a Posts
Re: Build it light! Build it true! Building tips?

>Some specific kinds of extra
>weight can actually make a given model fly _better


In a hurricane, maybe. High wing loading is not good. Heavy is bad, bad.
Newton's Laws prevail, check'em out.
Dr.1 Driver
"There's a Hun in the sun!"
Old Oct 31, 2003, 04:00 AM
Morgans
Guest
n/a Posts
Re: Build it light! Build it true! Building tips?


"Dr1Driver" <dr1driver@aol.com> wrote in message
news:20031030220309.03753.00000063@mb-m06.aol.com...
> >Some specific kinds of extra
> >weight can actually make a given model fly _better

>
> In a hurricane, maybe. High wing loading is not good. Heavy is bad, bad.
> Newton's Laws prevail, check'em out.
> Dr.1 Driver
> "There's a Hun in the sun!"



Why is it that slope gliders, ballast for better penetration?

General rules are "always wrong" <g>
--
Jim in NC


Old Oct 31, 2003, 07:00 PM
Dr1Driver
Guest
n/a Posts
Re: Build it light! Build it true! Building tips?

>Why is it that slope gliders, ballast for better penetration?

That is exactly why, and the ONLY reason they use ballast. A heavier plane
DOES penetrate and fly in wind better, but that's the ONLY reason to add, or
not take out, weight. As I said, "In a hurricane, maybe."

And Newton's Laws are not "general rules". They are scientific facts that every
object is affected by.
Dr.1 Driver
"There's a Hun in the sun!"
Old Nov 01, 2003, 04:00 AM
Dan Thomas
Guest
n/a Posts
Re: Build it light! Build it true! Building tips?

"S. Boucher" <*****ssboucher@westpa.net*****> wrote in message news:<bnseb00te5@enews2.newsguy.com>...
> Light?????? True??????????
>
> If my plane hits the ground, I want the earth to shudder before I
> backhoe it out and restart it.


I haven't seen any backhoes at model fields yet. How much buried
treasure is there as some of the places you've flown?

Dan
Old Nov 01, 2003, 04:00 AM
Dan Thomas
Guest
n/a Posts
Re: Build it light! Build it true! Building tips?

Fred McClellan <the-plumber@mindspring.com> wrote in message news:<a613qvsug0iealvatkhjai65od4o89nts3@4ax.com>. ..
>
> On your next film-covered-open-bay-wing model, build two wings.
>
> Build one wing by the book, and build the second wing sheeted with
> balsa and then cover it with film.
>
> When you're all done and have collected two dozen flights on each
> wing, throw out the wing you don't like to fly.
>
> I'd bet real money you'll likely keep the sheeted version.


Very good possibility. On full-scale fabric-covered wings,
there is a drag penalty caused by spanwise flow running over the high
spots along each rib. The airflow is NOT straight along the chordline
from leading to trailing edge if the wing is generating lift; the
higher pressure on the bottom is causing the flow to move outward
somewhat, and on the top, lower pressure pulls it inward. This is
where wingtip vortices come from. Smooth wings cause less drag, and a
sheeted and covered wing will be nice and slick. Further, the designed
airfoil will be the same anywhere along span, not just over the ribs.
The additional lift and lower drag could more than compensate for the
extra weight.

Dan
Old Nov 01, 2003, 07:00 PM
Bob Cowell
Guest
n/a Posts
Re: Build it light! Build it true! Building tips?


they fly like a brick compared to a decent flying model
if memory serves, some full scale planes fly at 100 POUNDS per square foot
they also take off and land at speeds well above what most models can reach.

If you don't think weight makes a difference, try just tying a couple of bricks
to your favorite flying model, take it out and fly it, and you WILL notice a
difference.


On Sat, 1 Nov 2003 07:43:07 -0500, "jflongworth" <strathboy@execulink.com>
wrote:

>I wonder how cargo planes fly Phil?


Old Nov 02, 2003, 04:00 AM
Philip Rawson
Guest
n/a Posts
Re: Build it light! Build it true! Building tips?

"jflongworth" <strathboy@execulink.com> wrote in message
news:vq7aii5jan2c05@corp.supernews.com...
> I wonder how cargo planes fly Phil?


Dunno... have they got wings?

Sorry, I can't be bothered... go and spend 15 years designing and flying
your own models, then look back at what you've learned...

--
Philip Rawson

www.flymodels.co.uk




Old Nov 02, 2003, 04:00 AM
Dr1Driver
Guest
n/a Posts
Re: Build it light! Build it true! Building tips?

>And don't forget sluggish acceleration, wide turning radius, longer
>takeoff run, longer landing rollout, slower roll rate, and a lower rate
>of climb.


Thanks Robbie. I forgot those until after I posted.


Dr.1 Driver
"There's a Hun in the sun!"
 


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