LSA nosebowl to cowl interface

[arborite]

I have one of Bob’s fiberglass nose bowls for the LSA. Looking at others’ photos, I see a joggle in the rear flange so the cowl skins can nest flush with the nose bowl. The bowl supplied by Bob is straight at the rear flange, not joggled inward. I don’t want to overlap the pieces and have that edge open to the wind. What are others doing with this nose bowl? I’m thinking I will add an aluminum lip inside and butt the pieces together. Is this what others are doing?

[jaredyates]

I have heard Bob say before that he has built up a transition there with epoxy and microballoons, using the aluminum sheet as a form. This eliminates the rather tricky job of trying to cut the aluminum sheet to match a preexisting joggle.

[arborite]

Yes, I found that Bob article last night. Personally I find trimming the aluminum a lot easier than laying up glass, but that’s just me.

so is this what current kit builders are doing? Looking for ideas. The nosebowl from Bob is pretty thin, so it will need a lot of reinforcement at key attach points, especially if I split it horizontally. I’m considering leaving the nosebowl as one piece and securing it with the four c channels. Then lower cowl is a separate piece screwed to the frame structure, like Piper does. Definitely want to be able to run the engine uncowled without removing prop, so either nosebowl has to be secure without cowls or split and removed with them.

[Sierra Skydog]

I added a fiberglass lip to mine for a flush fit. Building up a transition might be easier.

[arborite]

Thank you for those pics. Very helpful to see the details. Yours looks like a nice lightweight solution.

[PropMan]

20260121_192743.jpg 20251124_183208.jpg
I elected to get the fit as tight as possible without adding weight, no lip, just overlap and fastened. 20260121_192615.jpg

[arborite]

Very nice. How did you attach the c channel to the nosebowl? I’m making T shaped reinforcements where the top of the T is attached to the nosebowl and the leg extends inside the C channel. Bob recommends 4130 reinforcement plates, probably because the fiberglass isn’t durable without reinforcement.

or did you bend a 90 degree stiffener in the top cowl like Bob and not use the C channel in the kit?

[PropMan]

Here's my video that covers the cowl. I used 3/4x3/4 angle.

https://youtu.be/ewSagDOzH20?si=wihxtI3lPgpJP73y

[Sierra Skydog]

I used T shaped brackets for the C channel and backed up the fiberglass nosebowl with aluminum strips