Head installed crooked???

[Steve Riebe]

I've recently acquired a few older engines, 2 of them had the heads installed so the cooling fins were not in alignment with the shaft.  I realize this would be a disaster for an engine with a baffled piston, but am I missing something here?  Would there ever be some kind of advantage installing the head crooked?

[Tim Wescott]

I don't see an advantage unless (a) the pilot thought the engine needed to run warmer or (b) the pilot had some weird air ducting.

I think it's most likely that whoever had them messed up.  But then, I'm cynical.

[Chris Wilson]

There is a school of thought that runs "align the direction of the cooling fins to be parallel to the airflow," and since the airflow spirals .............

Well its not hard to join the dots if you think that you are facing the fins more directly into the wind by twisting them into it. Not that I believe its beneficial in any way.

[Steve Riebe]

Well now that's beginning to make sense.  The fins were off one set of holes CCW which would put them in line with spiraling air flow. Thanks!

[Steve Helmick]

If I was selling an engine and had some extra head shims that I wanted to include, not crumple or lose, I might just put them under the head and cant the fins like that to entice the buyer to take the head off and discover the shims. Just a thought. I've not heard of the above explanation for turning the head, nor seen it done, in any case.  Steve

[Howard Rush]

Air doesn't spiral that much.  If it did, the prop efficiency would be absurdly low.  I'm sure, Chris, with your vast aerodynamic expertise, you can easily calculate the angle. 

I have known people to rotate heads for the purpose of having the engine look cool (not in the thermal sense).  I suspect this to be the reason for the head orientation in question. 

[Chris Wilson]

Hi Howard,
              we are all guessing the authors intention here and since none of us know the author in question there are no wrong or right answers.

But I have heard that exact answer given by another for the same issue, and the original poster has already stated that the train of thought sketched by me made sense - so why the sarcastic jab?

For the record, and I repeat I don't agree that angling the fins is beneficial in any way and would never do it unless the air intake and exit were similarly angled as well.

Looking "cool" is as good an answer as any too.

Thanks.

[RandySmith]

I have on a couple of occasions put the head on sideways for winter flying when very cold outside, This did help as it lets the engine coll slightly less and helped the glow plug to run a little hotter. giving a cleaner run in the maneuvers. However this is something that is rarely ever needed

Randy

[Chris Wilson]

Another method of reducing the chill factor is rolling an 'O' ring down over fins and is very tuneable by using more or less rings as required.

[Phil Krankowski]

Another method of reducing the chill factor is rolling an 'O' ring down over fins and is very tuneable by using more or less rings as required.

I use yarn on my cox engines in the winter.  I wrap a couple turns into the gap between the fins on the glow head.  It is really funny getting 1/2 lap then the engine just cutting out.

Phil

[Steve Riebe]

Most recent was a Fox 40, a while back was a FP 25.  The latter I wrote off as the owner didn't know how to assemble and it had a stripped thread