Fluting 101... how straight is straight enough

[UnPossible]

Well - I'm finally jumping and starting my empennage. So far (the first few steps ) its going well. However I have a quick question about fluting.

How straight is straight enough? I read several threads with fluting tips. Using those, I got the ribs for the vertical stabalizer pretty darn straight in an hour or so. My question is how straight is straight enough? In the picture below, I clamped a flexible ruler along the holes. To me, it looks pretty darn straight. However, looking closely at every hole, there can be an extremely small variation in a couple of holes (I'd say around 10% of the hole diameter or less). So is this good enough, or do I need it to be absolutely perfect here?

Thanks,
Jason

[frankh]

The prepunch holes in the skin will soon tell you..If you can't jam the cleco in the hole then its not straight.

But your way cool there...Remember..your building a light aircraft not an F16...

Cheers

Frank

[Ironflight]

Lay the rib web side down on the table (flanges sticking up). If it rocks, you need to do a little more work. If it lays reasonably flat, you're good to go.

Frank is also correct - the cleco's will tell the truth!

Paul

[Jkkinz]

Jason,

As long as you get it straight enough to lay flat on the bench and then get the clecos in relatively easy when it is matched to the skin you are doing a good job. Remember that you will match drill the holes and that will certainly take up the 10% you see with the ruler

[Rivethead]

If you keep to that standard you're going to have a very straight plane....in about 20 years . Looks good.

[UnPossible]

Originally Posted by Rivethead

If you keep to that standard you're going to have a very straight plane....in about 20 years . Looks good.

That's partly what had me concerned. I grabbed the fluting pliers and had all 4 ribs for the vertical stabalizer pretty much straight in 15 min.... for some reason I expected it to take much longer. I fugured that I must be doing something wrong.

Thanks to all for the advise. Last night I clecoed the skin on, and the holes lined up with little effort. ... so to the answer to my orgional question is that they are straight enough.

Jason

[Peterk]

also don't forget the famous small stanley pick set. as you cleco you use a small pick to find to holes ahead and line them up before you get that far. its easier to find a misalligned (sp?) hole with a pick than a cleco.

[Andy_RR]

Whilst you're working at the ribs, try to get a little curve to the front flanges on the inner and (especially) centre nose ribs of the HS. They seem to be supplied a little too flat leaving a very noticeable 'flat' section to the nose of the aerofoil.

It's the only thing that really grates on me when I look at my HS. That and the rivet where the gun slipped and dented the skin - that's on the underside though!

Also, the more 90? the flanges are (or at least parallel to the skin) the smoother your skins will turn out.

Just my 0.02p FWIW

A