The International Cessna^® 170 Association

Has anyone done the Avcon/Williams conversion? I am in the middle of one and seeing that it was a bad decision but that’s beside the point. I am working on the cowling and I have the replica nose bowl from CAC Plastics in Alaska. The bottom nose bowl fits pretty nice but the top piece is about 1.5 inches taller than the top cowling and it looks like it needs to be so it will clear the spinner. It appears that the only way to make it fit would be to split the top cowl. The drawings don’t provide much guidance. Does anyone have any advise/pictures of how to make it fit?

I had similar issues . I was using Harry Dilickers STC and a fibreglass nose cowl. I ended up cutting off 1.5 ins off the top cowl and building the bottom cowl totally new to fit the engine . My original bottom cowl had patches on Patches and was badly cracked . I made it in 3 pieces and joined them together. to form the bottom cowl. Make the prototype out of stiff cardboard first and when correct paint them in epoxy resin . The 2 leading edges of each cowl has to be inline vertically. hint… My fibre glass nose cowl is in 2 sections and have them always screwed to get her when positioning top and bottom cowl for fit. send us your email and i will send photos of must do attachments of cowls to aircraft and split cowls. There has been issues before of cowls coming open in flight . That can make a bad day .

My Avcon was installed by a previous owner in 1973 so I don't know the process, but there's no evidence of extraordinary work performed to make things fit.

Pictures might help?

DaveF wrote: ↑Mon Apr 28, 2025 4:17 am My Avcon was installed by a previous owner in 1973 so I don't know the process, but there's no evidence of extraordinary work performed to make things fit.

Pictures might help?

Good quality work should not look like it was jury-rigged to fit.

(doesn’t mean the original instructions and parts did not require fitment)

Ha ha yes, but judging from the quality of the work that I know they did, they didn't expertly conceal something more difficult.

I just purchased the cac nose bowl and loosely comparing it to the original avcon, which to note is very very damaged, looks fairly similar. I will be drilling off the old fiberglass in the next few days and can more accurately measure them. Will report back!

Where did you get info on the CAC nose bowl? I see nothing about it on their website.

Just have to call and ask for it. I want to say it was around $500

Be very careful about purchasing fibre glass intake cowls. After hitting a pelican and my fibre cowl was in a number of pieces ,i hunted around for a new one . Some of the prices were beyond comprehension. So armed with a roll of kevlar and epoxy ,I repaired mine . But I looked at numerous other cowls and taking heaps of photos of other after market intake cowls ,I thought I had it in the bag . I was so wrong . The fit was “okay” but airflow wasn’t correct . It was a conversation with a drag reduction component company “De Pressy” I think this was how he said his name , helped me in design or reconstruction of my cowl. So be carefull of after market cowls ,they are not all what it seems .

PS. The pelican hit so hard ,it sheared or tore out the anchor nuts on the top screws that hold the top cowl to the fuselarge .

ghostflyer wrote: ↑Mon May 05, 2025 12:37 am... It was a conversation with a drag reduction component company “De Pressy” I think this was how he said his name , helped me in design or reconstruction of my cowl. ...

LoPresti perhaps?

abushey123 wrote: ↑Fri May 02, 2025 8:13 pm I just purchased the cac nose bowl and loosely comparing it to the original avcon, which to note is very very damaged, looks fairly similar. I will be drilling off the old fiberglass in the next few days and can more accurately measure them. Will report back!

That would be great. Thanks. The one I got from them wasn’t very even side to side. I had to cut about an inch off each end of the top piece to get it to fit and the curve wasn’t very well centered. IThe “blisters” had their issues too. I will have it done tomorrow and will post some pictures.