Reducing weight

[coffeedream]

Hi all,

I've built a 500 series Spitfire using kit wood and kit paper.

It's my first build, and I found the process difficult but entertaining.

The entire build weighed in at about 25 grams. But balancing the plane with weight in the nose put it over 30. The thing flew like a brick most of the time.

After several crashes i'm reworking the model, starting with the tail, to reduce weight.

Any suggestions?

Also, i find that the wing shears away from the fuselage often. Any way to reinforce the bond without introducing too much weight?

Thanks,
Rob

[Maurice]

Hi Coffeedream,
Let me say I love Guillows (biased) BUT, their wood selection is, well, somewhat on the heavy side but not always but mostly. I have built them stock standard and have been impressed with their vertical performance downwards. Now flights of well over a minute are regular. So what is the secret? There are many options. Guillows supply magnificent plans and I follow them religiously but I do the following.
Sand ALL fuselage formers to 1/32" (0.8mm).
Sand ALL wing ribs to the same thickness as the fuselage formers.
Change ALL the stringers to a lighter grade balsa. You will need to invest in a set of jewllers scales but these scales will assist significantly in identifying too heavy balsa.
With the wings, remove half the ribs; it doesn't detract from the wings performance at all.
Move the motor peg forward one bay; it will save adding a lot of nose weight to get it to balance.
If you are using 1/4" LE check the weight and if possible, use a Dremel or whatever, to groove out the back edge; makes it sugnificantly lighter.
With the keel parts for the top and bottom, use your exacto knife to cut out the "guts". Remember the wood is very strong and this will not weaken the model at all.
Replace the TE with 1/16"; the 1/4" is a bit on the overbuild side. Just put one piece against the start of the rib notch and the other piece of 1/16 at the far end of the rib. You will have a lot of kit wood left over but you will have a good flying plane.
Guillows are tough and I have a fine collection of well flown models that have gone on to survive time and time again.
If there is anything else I can help with let me know.
Maurice

[dbcisco]

I like the heavier wood in Guillow's kits because I electrify them. I have made very light ones from other mfg's and I wouldn't trust them with other than rubber power.

[cliffm]

When I was a young enthusiast if you couldn't put an .049 on it with a set ofU-control lines it didn't interest us unless it was for free-flight. the Guillow's models are engineered strong enough to withstand this type of use without falling apart in the air. Who cares about weight, just put some more power in it. That was the attitude we had before them guys with the batteries came along and now it's all about the grammage. Anyway, in the process of balancing """" a prop on my nieport II which is a real joy to build. Everyting fit beautiful. We'll see how it flies with the stock parts and white dope construction with about 3 coats of airbrush acrylics.

[skywarp]

I couldn't find a thread about this so I am putting my question here. Just to be sure but when balancing these Guillow's models do you balance them upside down like you do RC models, at the CG point on the plans? I just built the Typhoon (which for some reason has a P-51 canopy because that is what Guillow's put in the box... ) and I want try and get it balanced to see if I can get it to fly. Thanks for any advice.

[kittyfritters]

I couldn't find a thread about this so I am putting my question here. Just to be sure but when balancing these Guillow's models do you balance them upside down like you do RC models, at the CG point on the plans? I just built the Typhoon (which for some reason has a P-51 canopy because that is what Guillow's put in the box... ) and I want try and get it balanced to see if I can get it to fly. Thanks for any advice.

I've seen people treat them like big RC ships and hang them upside down, or use fancy balancing rigs, but I seem to do well, with the smaller ones by simply picking them up by the wing tips with my fingers at the suggested balance point. They are like any other flying model, you have to start with the suggested balance point before that first test glide.

Hi all,

I've built a 500 series Spitfire using kit wood and kit paper.

It's my first build, and I found the process difficult but entertaining.

The entire build weighed in at about 25 grams. But balancing the plane with weight in the nose put it over 30. The thing flew like a brick most of the time.

After several crashes i'm reworking the model, starting with the tail, to reduce weight.

Any suggestions?

Also, i find that the wing shears away from the fuselage often. Any way to reinforce the bond without introducing too much weight?

Thanks,

Rob

Of course they'll fly better if they are lighter, but the key is building them straight. With no warps, most of the 500 series will fly incredibly well up to about 32 grams, and the ones with the larger wings will fly reasonably well at 40. Having said that, the Spitfire and Hurricane are difficult to get to fly because they are very tail heavy. Anything you can do to reduce the weight aft of the C.G. will help. Running the wood through a thickness sander, reducing the width of the outlines of the wing, tail surfaces,and keels, substituting lighter wood, covering with colored tissue instead of paint (even over the plastic parts) all are good ideas.

Another useful modification is to move the motor peg one former forward. This gives a shorter motor with fewer turns, but is usually more than made up for by the motor becoming much less of an issue in the balance of the model. Anything you can do to make them balance without adding ballast is a benefit.

[skywarp]

Thanks kittyfritters. I balanced it at the point it says to on the plans. Now just waiting on weather to let me do some test gliding. Meanwhile I am putting the 16" WS spitfire together while my son is building his own Typhoon.

[coffeedream]

it sounds as though i'll have to start from scratch again to allow for the changes...