Balast?

[Clifford Stone]

I'm moving onto open class in F5J and Bartletts e-soaring in 2015. I have enjoyed 2m, so a move up seems a good idea? However, my open gliders are light, under 1500grms. One I want to keep that way the other, a Pulsar 3.6m MkI type, modified to be able to get at height limiter and battery with out dismantling half the model.

I was told the other day by a very experienced pilot, that the Pulsar is under estimated in its abilities in windy conditions. So I decided to have a look at the option of ballasting for wind. There is plenty of room, I have constructed a platform under the CG on which I can mount up to 14ozs!!! . . . in 3oz slugs + one 1 or 2oz slug, the whole bolted to the floor.

The question, is there a criteria for ballasting or is it suck it and see, and where do you think I might start if say the wind was 10 or 12mph . . . or more?

Thanks, CJS

[Clifford Stone]

Mmm . . . no takers, then I will assume it is 'suck it and see'. Very much the way I have gone about the very steep learning curve in 2m. Although one has to be very appreciative of the help one has received, especially in the power train department, which can get very confusing.

I have don a lot of trial and error on ballasting my 2m Sapphire, flying weight 680grs, then ballasted with 140 grams, this combination works really well in winds up to about 15-18mph, (it is possible to carry 200grams, but this turnes here into a brick with wings). As said, this has been trial and error but seems to keep Sapphire competitive with air frames that are better suited to winy conditions, its then all down to the pilot.

So applying the above logic, Pulsar 3.6m, will start with 180grs increasing to 270grs via 30grm and 60gram slugs? Suck it and see, the 90gr slugs are deliberatly that size to go along with my thinking and the fact that a strip of 3mm lead flashing x 6" x 1.1/8" weighs that! The floor is designed to take that dimention as standard.

Looking at the weather prediction for East Anglia, I might get a few hours flying on Boxing day and have the opportunity to try the 180grm setup? Pulsar is still in the early stages of trimming out, seeing what setup suits what conditions and simulating competition flights . . . Fortunatly there are a few pilots in the club who are interested, so we fly against each other and compare notes, it can get very intense on occasions when 'the competitive red mist comes down'.

CJS

[Steve T]

When you got no response.....was there a gentle breeze with tumbleweed rolling across your keyboard?

[Clifford Stone]

Mmm . . . if it had been only a 'gentle breeze' Steve, I would not need ballast . . .

CJS

[Tom Satinet]

IIRC I saw on a post on rcgroups by Joe Wurts where he said he ballasts so that his min sink settting is not flying backwards for a given wind speed.

The amount of ballast really depends on how light the model is and other factors, such as how fast it flies (etc). Obviously at a basic level ballast increases you ability to cover the sky, which is why people tend to fly it when it's windy. i.e more windy more ballast.

yes I think it is mostly suck it and see because ballast is quite airframe specific, and also condition specific. There are too many different conditions you can encounter for there to be a ballast check list IMHO.

At 1500g your model has a very low wing loading. to be honest 14 ounces of ballast is not that much. I think a lot depends on your thermal tactics. Some people seem to rely more on the low minimum sink rate of the model rather than its ability to cover ground and find lift. 12mph on the ground will be a lot more once you get higher up.

Edited By Tom Satinet on 23/12/2014 14:51:12

[Clifford Stone]

Posted by Tom Satinet on 23/12/2014 14:49:13:

IIRC I saw on a post on rcgroups by Joe Wurts where he said he ballasts so that his min sink settting is not flying backwards for a given wind speed.

The amount of ballast really depends on how light the model is and other factors, such as how fast it flies (etc). Obviously at a basic level ballast increases you ability to cover the sky, which is why people tend to fly it when it's windy. i.e more windy more ballast.

yes I think it is mostly suck it and see because ballast is quite airframe specific, and also condition specific. There are too many different conditions you can encounter for there to be a ballast check list IMHO.

At 1500g your model has a very low wing loading. to be honest 14 ounces of ballast is not that much. I think a lot depends on your thermal tactics. Some people seem to rely more on the low minimum sink rate of the model rather than its ability to cover ground and find lift. 12mph on the ground will be a lot more once you get higher up.

Edited By Tom Satinet on 23/12/2014 14:51:12

Hi Tom thanks for the reply. As you will have realised, this is a learning curve for me, my first season having just passed, reasonably successful in that I won the Ipswich club glider trophy. I find following thermals down wind hard, going against the grain, knowing that getting back is the issue, hense the ballast, as well as searching for thermals and good air. To fast and I find it difficult to recognise before I have passed through.

As I say, my club mates are very helpful encouraging me, passing on tips despite the fact that we are competitors in competion.

CJSF