Building Light - Page 3 - RC Groups
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Jan 17, 2002, 03:19 PM
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Pat Daily's Avatar
Chuck is right!--Building light is a state of mind and a lifestyle. I have been trying to build light for most of the past 30 years as a free flight scale modeler. While I could build sorta light, there are some real experts out there --like Dave Rees and Alan Schanzle --they build very light. The trick is the design and not overdoing it. I keep trying to learn but usually overbuild. Besides using the right weight and size balsa to do the job, think about how much glue you need. CA glues are heavy and most of us over do what is needed. One of the best light scale builders was old Ned Cragness and he would put the CA in a bottle cap or something like that and use the eye of a needle to apply very small amounts of it--if you try using the tube and bottle, you are sure to put too much glue on the joint.

Pat Daily
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Jan 17, 2002, 09:23 PM
in persuit of low wing loading
Gordon Johnson's Avatar
Dave Robelen told me that building very light contest FF indoor models for years is a good aprentiship. He also said one thing about very lightly built models is that rather than break in half when crashed, they kind of explode.
Jan 17, 2002, 11:15 PM
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Pat Daily's Avatar
Well, light ff models don't break as much as heavy ones because they tend to fly slower -- but the real trick is not to crash 'em anyhow. Real planes also tend to explode when they crash because they are built lightly for their size and not intended to be built to survive a crash. The trouble with many of our models is that they are built to survive poor piloting--therefore they are too heavy. Don Srull has some neat paper airplanes that he makes for rc--prints the colors and design and then uses balsa sticks for the leading and trailing edge--sort of like 3 dimmensional nocal ff jobs--very light wing loading, very slow flyers and very rugged.

Jan 30, 2002, 08:02 PM
Only nerd in the village
I have discovered the sometimes even Depron can be too heavy. I have just finished a 12.5" model for a one cell/pager motor setup. Total airframe weight is only 2.8 grams incl. U/C and wheels. AUW will be app. 12 grams

When building the wing I first sandes some Depron to a thin airfoil section but I was still at 0.9 grams pr. wing half. Then I decided to try some 4mm wall paper backing foam (beaded styropor) and even with 1mm carbon fibre spars the total weight for the wing was 1 gram.

Fuselage is from 2mm wall foam and tailfeather are from 1mm pink foam because it is stiffer than wall foam.

I was quite surprised that it was so easy to build a model this light.

Jan 30, 2002, 08:48 PM
Registered User
microflyer77's Avatar

pressed styrofoam plates

The fact that a ready low-cost supply of sheet foam exists (in the foam plates) is just as exciting an improvising discovery as Saran wrap for coverings.

But we need all experienced micro e-flight people to share this information. I'm sure some of us know where to get bigger sizes of rectangular foam plates. Please let us newbies know.

BTW, meat tray foam may be a tad heavier than foam plate material -- or am I wrong on that count?
Jan 30, 2002, 08:52 PM
in persuit of low wing loading
Gordon Johnson's Avatar
I'm able to get foam Depron like cafeteria trays in my building. They are kind of on the thick side, however, at about 3.5mm. They are larger than meat trays.
Jan 31, 2002, 12:00 AM
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microflyer77's Avatar

cafeteria trays

This would be a commissary then? Anyone know of any retail chains serving large foam trays? Love's? Luby's?

Mickey-Dees Breakfast trays are a tad on the small side but are thinner -- 1mm or thereabouts?
Jan 31, 2002, 08:20 AM
Sticky Shepherd
Graham Stabler's Avatar
I got some meat tray foam from the main supplier in the UK and it was much heavier than depron. It also had a tendancy to crack. I suppose it depends who makes the stuff really.

Epilot, you can't beat wallpaper backing foam for the ultimate in lightness. Its great for curved fusulages made from one piece without a single former except for the nose. Aeronut Mark is always going on about the stessed skin construction, he's convinced the F16 was based on one of his models

Feb 03, 2002, 05:09 AM
Registered User
On most plane designs, the wing CG to tail length ratio to prop to same wing CG point is 3 or 4 to for every 1 gram or 1oz removed from the tail, 3 or 4 that amount can be removed from the nose , for a total of 5 gram or oz total lighter and still be in CG ballance....For a really light model, cut out from 1 piece of 1/8 depron or equiv. a stab or elevator as usual But cut out large open areas leaving 1/4'' to 1/2'' intergrated "ribs", leading, trailing edges and wing tips...then cover Only the top or 1 side of vertical fin and rudder with Lite-span....makes for a very fast building and light
Feb 03, 2002, 01:24 PM
Registered User

Do you have pictures? I would like to see where and how you are including the cf spar.

Feb 04, 2002, 10:21 PM
Our Daddy and Heli Junkie
Fred Bronk's Avatar
Lets keep the talk about planes and building here guys.
Feb 05, 2002, 04:20 AM
Most Exalted Windbag
Feb 05, 2002, 08:27 AM
Registered User
Dave Wulff's Avatar

Have I missed something?
Feb 05, 2002, 08:40 AM
Sticky Shepherd
Graham Stabler's Avatar
I think we all have
Feb 05, 2002, 03:05 PM
Registered User

Newt Spittle

I think he took out the part about the Newt Spittle.

If you want to build light, dont use any components at all, don't look like a plane or fly, so add just enough parts to make a plane fly
It is often easier to add strenght afterwards, but I have rearly had to do so.
Adding strenghening to the outside of a plane is a good idea anyway because a stiff skin is much better than spars and such like because it is further away from the centre line of the bending plane

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