cutting scale exhaust opening...

[Cyclicscooby]

Hiya guys...
Long time, no cyclic.....

In trying to fit new scale pipes to a bell 230, where the pipes come out at a angle..
I've tried a card template, trimming and trimming, and a sheet of balsa, but I'm not happy with the results..
Does anyone know of a better way of marking the hole...?
The pipes are 35mm diameter, if that helps...
To add to the grief, the fuse is curved aswell, and I haven't taken that into account yet..!
I'd love to add pics, but I'm posting on my phone...

Luv Chrisie xx

[xygax]

its an idea that will work well but it may take quite a while...

Model both the pipe and section of the fuse in solidworks that will give you an intersection line that you could print to a template...

(No i dont have solidworks)

[Cyclicscooby]

Hi Steve,
I presume that's a 3d cad type o thing.. ?
I'll have look at some torrent sites, see if I can get it....

Thanks for the reply

Luv Chrisie xx

[nitromad]

how is the hole to be made ? , i mean are the pipes just and panel or hole body side ?

personally i would cut the coweling off main body (if needed) mark up and cut openings that way then either glue back inplace with extra support or make removable,but this all best if body is unfinished ,coweling marking up is the simplist way no extra special things needed just lots of ruler time. also have you got anything like veriper calipers would help in finding out dia of pipes at exit of body and then be transfured to the cured body with adjustments.

but like i said im just guessing as i not sure on body you using etc

gavin

[Cyclicscooby]

Cheers Gavin,
It's a Jr f-glass 30 size (for voyager E) -
if u click my username, there's a pic of it on my scoobys bonnet
It's only a front n rear fuse, no other panels come off..
There are stickers for pipes, as is, but as I've just made
ally retracts, it needs zorsts now to finish off...
It's un re-painted, so not fused about marking things..
I've made two pipes from a drinks can, and the plan is
to cut holes in fuse, and glue in the pipes from inside once I've
Flanged...
Does that make sense..?

Luv C xx

[nitromad]

yea i get you

i would in that case use the pipes them self as template mark on the out side and cut SMALLER then with hand file for best finish slowly open holes up until the pipes fit if u go to big u can also use modeler's filler i think most important part is getting both pipes looks mirrored that will the hardist no matter how carfully u marked out first.

gavin

[Vic.P]

Hi Chrisie,
What were you planning on using to cut the holes with? It sounds like you are marking out the hole with the idea of sawing it out along the marked lines?
As an idea, you could try using a 35mm hole saw and drill arbor. So long as you know where the centre of the hole should be and the angle that the exhaust pipes should exit the fuselage, then the hole saw should take care of the problem with the curvature of the fuselage. It would be worthwhile putting something on the inside of the fuselage to reduce the chance of breakout when the hole saw is nearly through. Sounds a bit brutal i know, but it should get you very close to what you need and any fine adjustments can be made with a curved file or Dremel drill until the exhaust pipes are sitting right before epoxying them from the inside of the fuselage.

[Cyclicscooby]

I thought about using a hole saw drill thing, but I'm worried ill bust the gel coat...
I've found the best method for cutting is a round needle file used like a saw, it doesn't
Crack the gel, and I can fettle it smooth with a curved needle file...
I've just marked the holes on the fuse using cardboard templates... hopefully they'll end up
Square....
I'll see if I can get pics up to explain myself better......

Many thanks for all the replies...

Luv C xx

[Vic.P]

I thought about using a hole saw drill thing, but I'm worried ill bust the gel coat...
I've found the best method for cutting is a round needle file used like a saw, it doesn't
Crack the gel, and I can fettle it smooth with a curved needle file...
I've just marked the holes on the fuse using cardboard templates... hopefully they'll end up
Square....
I'll see if I can get pics up to explain myself better......


Many thanks for all the replies...

Luv C xx

If you tape over the area with a good quality masking tape before drilling it should help to prevent the gel coat chipping. Also, once you have the centring drill bit in you can extend the drill bit to the shank to prevent the drill widening the pilot hole and then run the drill anti-clockwise or remove the hole saw from the drill and turn it anti clockwise by hand so that it goes through gently without the teeth biting and digging in, effectively filing the hole out but you'll need a sharp brand new hole saw to do it.
If you have an old knackered fibreglass blade or anything else with a gel coat then you could practice on that first before committing to doing it on the fuselage to check it will work without chipping the gel coat.