Lower Cowl Lip size

How to keep the Cessna 170 flying and airworthy.

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minton
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Joined: Wed Mar 23, 2005 2:20 am

Re: Lower Cowl Lip size

Post by minton »

DWood wrote:Bruce;
I had looked into making one, but it doesn't look very easy. If anyone has ideas on how to do it, please let me know.
Thx,
Dan
I have a paper pattern of 0552001-60 seaplane lip for $10.00 plus postage.

There are no compound bends in the lip.

Anyone can manufacture one under FAR 21.303

Original material is 2024-T3 x .032 and held in place with AN515-8R5 screws and AN365-832 nuts on the C-170B models
ragwingrick
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Joined: Fri Feb 11, 2011 10:44 pm

Re: Lower Cowl Lip size

Post by ragwingrick »

I was looking into the reason for the differance between the large lip on the ragwings and the early A modles. I was looking at some early pictures in a book on the history of Cessna. There is a picture of two 170A's one with a large lip and one with a small lip. The caption under the picture said the reason for the change in size was to reduce buffeting felt under the rear seat.
bagarre
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Joined: Thu Sep 30, 2010 11:35 pm

Re: Lower Cowl Lip size

Post by bagarre »

n2582d wrote: 108. Engine cowl per Cessna dwg. 0552001 or 0552002
Includes 3/4"-45° lip on bottom cowl
required for seaplane
Does this mean the 3/4"-45 degree lip is not required if it's not a seaplane?
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Poncho73
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Re: Lower Cowl Lip size

Post by Poncho73 »

FYI to this old post. My 48 had a 3" lip and always ran about 180 degrees or so in warm temperatures. I trimmed it to 3/4" lip and it still runs 180 degrees in warm temperature. The other noticeable gain in going with a smaller lip is an increase in cruise speed. The 3" lip is nothing but drag, it's like flying around with the cowl flaps open on an old 180. I saw a speed increase of 2 - 3 mph in smooth air with the small lip.
bagarre
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Re: Lower Cowl Lip size

Post by bagarre »

I'd be interested to see Cessna dwgs. 0552001 or 0552002 to see whats actually stated about the opening and said lip.

There is a thread on here where a person with an IO-360 had no lip. In fact, the lower cowl was extended back along the contours of the cowling to make a smaller opening all together. The experimentals (RVs) do this as well and have rather small openings without cooling issues.
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DaveF
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Re: Lower Cowl Lip size

Post by DaveF »

On the other hand, a good friend had problems with very high CHTs on his newly-completed Rocket. His first fix was a big lip on the lower cowl outlet, and that worked very well. He's since moved on to lower-drag solutions, but the lip sure worked. I joked that he had the only seaplane Rocket in the world.
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DaveF
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Re: Lower Cowl Lip size

Post by DaveF »

minton wrote:I have a paper pattern of 0552001-60 seaplane lip for $10.00 plus postage.

There are no compound bends in the lip.

Anyone can manufacture one under FAR 21.303

Original material is 2024-T3 x .032 and held in place with AN515-8R5 screws and AN365-832 nuts on the C-170B models
Is your offer still good? If so, I'd like to take you up on it.
twlareau
Posts: 68
Joined: Fri May 13, 2011 3:20 am

Re: Lower Cowl Lip size

Post by twlareau »

Dave,
You are more than welcome to try the one we made and see how it works on your bird. It made no difference on mine. Well, it did make more of a rumble on my floor boards but your mileage may differ.
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ghostflyer
Posts: 1390
Joined: Mon Apr 21, 2008 3:06 am

Re: Lower Cowl Lip size

Post by ghostflyer »

I had to rebuild my lower cowl when I put the o-360 in it and the bottom of my cowl is flat and my opening is 2.5ins wide . My lip started out about 3ins wide and now is about 2ins wide at a angle of about 40 degs . I originally had it at 90degs and it sounded like a 747 at full bore in the cabin . So a little experimentation was carried out and the lip was slowly brought back to where it is now . In a full climb at max power my CHT,s run between 360 to 380 degs . Max. However in a prolonged climb at around 80 to90 kts the CHTS , drop to 345 degs . WHY ??????? I do not know . Oil temps sit at 183 degs constant . However your baffle condition is very important and no leaks between the top chamber of cooling air and the bottom chamber of used hot air should be allowed.
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minton
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Joined: Wed Mar 23, 2005 2:20 am

Re: Lower Cowl Lip size

Post by minton »

DaveF wrote:
minton wrote:I have a paper pattern of 0552001-60 seaplane lip for $10.00 plus postage.

There are no compound bends in the lip.

Anyone can manufacture one under FAR 21.303

Original material is 2024-T3 x .032 and held in place with AN515-8R5 screws and AN365-832 nuts on the C-170B models
Is your offer still good? If so, I'd like to take you up on it.
I have 3 paper patterns made up. Send $11.00 to John Minton/6425 switzerland dr/anchorage, AK 99516 with return address and one will be on the way.
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mkraynick
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Re: Lower Cowl Lip size

Post by mkraynick »

Have you still got these patterns? I could use one.
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cessna170bdriver
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Joined: Mon Apr 22, 2002 5:13 pm

Re: Lower Cowl Lip size

Post by cessna170bdriver »

I don’t think John Minton is a member anymore. The most recent directory he shows up in is from 2013. Your best vet might be to write him at the address he gave.
Miles

“I envy no man that knows more than myself, but pity them that know less.”
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