Hi Guys,

I am in the process of making a mould for a BM v2.2 for a composite fuselage. I have some problems in deciding how to do the belly pan.
I will be using a 2 stroke (OS 160) setup.

The problem is: What is the best? A short bellypan to the wing LE with a tunnel for the pipe from there onwards, or a full length belly pan to the end of the pipe, fully enclosing the pipe?

Can you guys give some pics of typical setups used in composite fuselages.

We are going to CNC mill the mould, so we want to get the design right before starting to mill the mould.

Regards
Attie

PS. Why the route of milling and a composite fuse?? We have access to a CNC milling machine (free of charge) and lots of carbon and Kevlar cutoffs.

The full length pan makes life easier. My question is do you have the designers permission to do the composite fuse? Are you going to try to sell these?

Hi,

No we are not going to sell these. Just for me an my partners own use and to go throught the steps of building a composite fuse.
It is actually a lot of work to generate the 3d models and transfer to cutting software etc. Just doing it for the fun.

Regards
Attie

I really don't have a problem with it, as long as he doesn't sell them in the US However, you may get some nibbles....so if it works out, let me know, and we can do something.

Structurally, I'd suggest a shorter belly pan going to just behind the gear. Then a pipe tunnel can be made using a false floor for a long exhaust. A fulle length pipe tunnel may not be the best option on a composite fuse. Easy yes, but might be a real headache in reality.

Just a thought.

-Mike

Hallo Mike,

Thanks for the advice. A question? Why do you think a long pan might be problematic? Is it the low fuse depth across the canopy that you expect might be problematic in terms of strngth? The fuse floor with the long pan might make up in structure for this problem with the adde bonus of reinforcing the fuse across the width?

If we go the short pan route with a tunnel, do you think one built the fuse to the actual bottom outline and then cut the tunnel area out. Lastly bond in a u shaped tunnel?

What is the fuse weight to aim for in a composite version? Any suggestion regarding layup schedule. It is so easy to make it too strong and heavy....

Thanks

Attie

If you go down the long belly-pan route, I'd suggest you mould in a fixed canopy.
Hatches in the false pipe-tunnel roof can give you access to the fus. interior.
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Hi Guys,

We have started cutting the plug on the CNC machine. It is a lot of work. The rough cut alread took 6h machine time. Will post some pics soon.

Regards
Attie

Here are some pice of the cad shapes and the toolpaths for cutting the plug. If I get to understand how to load the pics.

Attie

Wow that looks really cool!

-M

Here are som more pics
Attie

Sorry lost the pics...

again- sorry, will try again

some more
ASJ

Wow that is just too cool, looks like you've have a slightly different contours around the cowl checks and chin area maybe.

I need to get that cnc machine in my shop, I am sure I can get a second mortgage on the house.

wow....

Ok Attie, how much to do me up a plug like that for a new plane? LOL

Man awesome!!!! BTW please tell me you made the 2.2 mod on it? it's a fantastic plane as a regular 2, but since you're going through that much trouble and expense, I HOPE you at least made it the best version....

-Mike

Hi Guys,

We completed the final cut of the plug today. The final shape is really beautifull.

Mike, we tried to include all the mods you posted. Then we looked at all the V3 pics and tried to update our model to V3 from the pics. But that is only a guess. The fuse is now very wide.

We will send you the CAD files if you want it.

Perhaps we can cut you a plug for a couple of V3 kits …..

Here are the pics.

Regards
Attie

Hmmmmm......

Yeah sounds like we need to chat at some point

-Mike

Another pic of the complete fuse side.

Attie

OK,

After a long time we got the moulds finished and the 1st model out of the mould.

It is probably a little heavy. It weighs 880 g with the LG block and all bulkheads except the firewall.

Will put some pics on this afternoon.

Regards
Attie

Here are some pics

Regards
Attie

Some pics of the internal structure

The ribs are 3mm balsa with light glass on one side. Some kevlar on the 1st bukhead and the sides.

The shells are made of 3 layers of 60g/sqm glass with 1.5mm Herex foam on 60% of the area.

Regards
Attie

Hey Attie...

now that is cool... looks more like a v2.9

looking forward to seeing it finished....

great work... !!!

dean

that looks really cool. It almost looks like a cross between the V2 and V3.

Hi Guys

Yes, we made all the version 2.2 mods and then looked at the pics of V3 and tried to include those mods on a eyeball level.

So it is perhaps a V2.8 to 2.9

Regards
Attie

Yep, you're at about a 2.8 there....LOL

Great job! I look forward to hearing how it flies..

-Mike