Winter Kit for Champ 7AC

[Rattler 1]

I flew my 46 Champ 7AC today at 17 deg outside temp after installing an oil sump cover along with the oil cooler cover and block off plates for the cowel intakes. I also installed a Cyl temp guage on the RH rear cylinder. The cylinder temp reached about 390-400 deg. Oil temp was 155 deg and oil pressure at 28 deg. I think I got the right combination for winter flying. Oil pressure was at 35 PSI on the ground but dipped to 28 with the warmer oil temp. I use 20-50 in the winter. May get a little more pressure if I went to a higher weight oil but I think I'm OK as is. Anybody have any input, I would be interested. Below is the pics of the cowel plates.

Thanks.

 

[Bartman]

An oil temp of 155 is pretty good for such a cold day. The engine's a C-65?

 

[Rattler 1]

An oil temp of 155 is pretty good for such a cold day. The engine's a C-65?

A65-8

 

[Wisconsin7eca]

I would not block that much of the cowl inlet off, CHT gauge notwithstanding. You are going to cause hotspots and fry those jugs doing that, and 400F is too high CHT. I have a Chief that I block the outlet on the bottom 3/4 or so off. This is the preferred method, and I can achieve those oil temps while keeping the CHTs in check. We have several 7ac Champs on the field that do the same thing. You can keep the oil sump ram inlet covered like you have, that is fine. But I would not cover any of the inlets. I also have a 7ECA with an 0-235 that I also made a cover on the bottom. There is a drawing somewhere for this from Aeronca (might be the L16 manual) that covers this. There is also more information online.

 

[Rattler 1]

I would not block that much of the cowl inlet off, CHT gauge notwithstanding. You are going to cause hotspots and fry those jugs doing that, and 400F is too high CHT. I have a Chief that I block the outlet on the bottom 3/4 or so off. This is the preferred method, and I can achieve those oil temps while keeping the CHTs in check. We have several 7ac Champs on the field that do the same thing. You can keep the oil sump ram inlet covered like you have, that is fine. But I would not cover any of the inlets. I also have a 7ECA with an 0-235 that I also made a cover on the bottom. There is a drawing somewhere for this from Aeronca (might be the L16 manual) that covers this. There is also more information online.

I haven't been able to find a picture of the block off plate you mentioned above. Any help here would be appreciated.

Thanks.

 

[Rattler 1]

On one of the threads I was told there is a block off plate for the lower cowl in the rear bottom where the breather tube is that blocks off about 3/4 of the air flow that is used instead of plates on the cowl intake on the front. I'm looking for a picture or drawing of this. Can anyone help?

 

[Rickw]

I would like this info also

 

[Wisconsin7eca]

I will take a picture of my lower cowl block off plate I made, just give me a few days. This is more of trial and error type of thing and you don't want to close off too much. On my pre-war chief, the plate made a vast improvement the first time I put it on. It brings the oil temp up nicely, as it runs around 160+ degrees when its 25-30 F outside temp or so. It usually runs 100 over ambient so this is a pretty good improvement. This is an A65 so you are not going to get too much heat out of it, but it also has the benefit of a warmer cabin as it slows the air coming out and keeps the firewall warmer, which in turn keeps the cabin warmer. I cover off the lower cowl oil kidney inlet below the prop hub also. I installed rivnuts for this and I can take the cover on or off as I please, and no messy duct tape. I remove the plate when the temp rises above 40.

 

[Rickw]

thank you so much

 

[Rattler 1]

I really appreciate your help with this. I'll owe ya one,.

 

[Champdriver]

Here's two photos I saved from somewhere to show you the area blocked off. My guess is that this might be too much to close off, but it gives you an idea of what it may look like and the attachments.

 

[Rattler 1]

Here's two photos I saved from somewhere to show you the area blocked off. My guess is that this might be too much to close off, but it gives you an idea of what it may look like and the attachments.
View attachment 6226
View attachment 6227

This is great. Thanks

 

[Wisconsin7eca]

Ok, here are pictures of lower cowl block off plate on prewar Chief.

 

[Wisconsin7eca]

Here is front cover on the prewar Chief used in conjunction with lower cowl cover.

 

[Rattler 1]

Here is front cover on the prewar Chief used in conjunction with lower cowl cover.

Thanks for the pics. I do have the front cover installed. I will be making the lower cowl cover this week.

 

[Bartman]

merged the two winter flying threads.

 

[Rattler 1]

Here's two photos I saved from somewhere to show you the area blocked off. My guess is that this might be too much to close off, but it gives you an idea of what it may look like and the attachments.
View attachment 6226
View attachment 6227

I built a plate almost identical to yours pictured here except I put in a 2 inch by 4 inch hole in it with a sliding door that is controlled by a cable from inside the cab. This will make it possible to adjust on the fly. It has a two inch hole for the gas drain and the slot for the breather tube like yours.
I ordered CHT senders for all 4 cylinders so I can monitor the CHT along with the oil temp. Probably be able to install all of this next week and try out. I will post pics and results then.

 

[oldblue]

Here is the resource I used in creating one for my champ. I didn't use the design in the drawing but rigged up something close

https://www.bowersflybaby.com/tech/petegavin.winterops-1.pdf

 

[Bartman]

Here is the resource I used in creating one for my champ. I didn't use the design in the drawing but rigged up something close

https://www.bowersflybaby.com/tech/petegavin.winterops-1.pdf

excellent info, thanks for sharing!

 

[Rattler 1]

I got the outlet baffle installed and tried it out today. It was only 25 degrees out today. Will be testing in colder weather in the future. That said, the cylinder temp was around 350 deg. Oil temp reached 150 deg. Oil pressure stayed at 30 psi. I have a vent door that I can open and close from inside the cab but it didn't seem to make any difference. Seems there is sufficient air flow through the hole for the fuel drain and the cutout for the breather tube along with about a 3/4 inch gap in the rear. So far I am happy with the results. I'm not too concerned if I fly in colder weather. It's what outside temp I will need to remove the baffle. But for now, it works. I attached pics of what I made. The foam weatherstripping in the last picture blew out in flight which made the 3/4 inch gap. I'm leaving it that way.