The International Cessna 170 Association

Bruce, surely you're not trying to teach me what is under the hood of a 170 cowling.

The point I was hoping to bring home to Butch is that the cowling conversion he imagines is not that advantageous over the later cowl for inspection purposes....particularly with respect to the trouble, cost, and certification issues he probably didn't foresee.

EITHER set-up can be inspected by sitting on the ground with a flashlight and peering up the cowl-lower-exits.
A flashlight and a mirror can go a long way to a preflight inspection. And we all know that an oil leak on a O300 is not difficult to detect.
In the case of such findings,...the cowl on BOTH TYPES will have to be removed to properly address the issue, ...and the aforementioned troubled
cowling conversion will not be seen to have been particularly helpful and certainly not frugal.

Butch, with a fat wallet, anything is possible. If you go for it..... Write up an article for the 170 News. I'll pose for a pic with a spoonful of crow.

gahorn wrote:Bruce, surely you're not trying to teach me what is under the hood of a 170 cowling.

Well in RED airplanes you will find a round cage with a hamster. You probably have not seen that through those restrictive cowl openings your '53 has.

Approval aside (as is always the case), what's so difficult about putting a '52 cowling on a 57 172?
They are the same fuselage, the same motor, the same motor mount, same exhaust...everything is the same except the cowling.

Take the entire cowling to include the nose bowl and use the '52 baffling as well. The whole job should take 15 minutes and about 30 screws.

Other than getting the FAA to approve it: where's the difficulty?
In fact, I don't think the approval would be that difficult either since they are the same airplane in every way except landing gear. If it was good enough to cool a '52 170, its good enough to cool a '57 172.
It shouldn't be any harder than getting 175 wings approved for a 170.

The only feature of the airbox cowling that I like is the shape of the grilles on the nosebowl.

The rest of the cowling is a pain in the ass, to include the baffling. Because of the precautions that must be made with the latches, I see that cowling as more of a liability than a convenience. If the older cowling were more substantial and was a pressure recovery baffle setup (think Bonanza), it would be much better. With the slight curves and less/smaller doors, I think the pressure cowling is a prettier design.

Otherwise, it's too flimsy, too complex, too many parts rubbing in too many places, and too many air gaps.

Ok ! I give up on the "door" verses the "no doors " type airplane cowlings ! I now realize that the !70's , Stinson's , Tripacer's , Pacer's, Cheerokee's , and etc. were all built wrong for having the extra ability to do a better preflight inspection by having "doors . Hope no one gets mad at me for saying this , the ButchPilot !

Mad? Not at all, for a moment there I thought we had the makings of a " Wheel landings versus 3 pointer" thread. Another sign of a good post; George and Bruce throwing out bait to each other. Best of all, questions make most think whether they are thinking, an exercise that can't hurt but sometimes does.

Butch,

Please take my post in the spirit in which it was intended, and that is to give my opinion of a particular cowling versus another. It shouldn't be taken as gospel, only to interject my experiences with both to the conversation.

There are several legal installations you may use. The only two opinions that really matter at the end of the day are yours and your IA's. Everything else is just noise.

Butch, in many cases Stinson's, Tripacer's, Pacer's, Cherokee's where designed better. There I said it.

In fact I considered a Stinson, Tripacer, Pacer and owned a Cherokee before I owned my first 170. Like the Stinson's , Tripacer's , Pacer's, Cherokee's a Cessna 170 is a dam good airplane, but it's not perfect. I've still owned twice as many Cessna's as I have any other.

Funny you mention a Cherokee. Ever try preflighting a larger or later example? Worse than a 172 as you only have the little oil level "6x"6 door to peer through. Like the Cessna, Cherokee's went down hill in the department of easy engine access as the years went on.

I have seen a couple of 170 A.s have a modified cowl that did away with the plenum chamber . It wasn't very well done and had cylinder cooling issues . When I did my conversion to the 180hp lycoming the bottom cowl had to be be totally rebuilt . Even the new nose bowls had to be strengthen . This area was the most labour intensive of the whole conversion . So my advice before people start changing cowls get some good (expensive) advice . This area is a black science . I use 7 cam locks to hold each cowl half in position . This method was taken from Beechcraft . Personally I like the plenum chamber system , it's the most efficient system .

Bruce and I agree that Cherokees are a pain to preflight.
Especially as I get older.
(Who wants to get down on the ground and crawl around to drain fuel sumps?)