Cowling compatibility
Moderators: GAHorn, Karl Towle, Bruce Fenstermacher
Cowling compatibility
The cowls on my 48 are fairly worn and almost beyond economic repair. I have a set of 53 cowls, they are slightly different. Question, can they be switched out and is that approved? Yes the 53 has both access doors on the upper cowl.
- cessna170bdriver
- Posts: 4063
- Joined: Mon Apr 22, 2002 5:13 pm
Re: Cowling compatibility
I’m fairly sure the newer cowl would fit the airplane and engine, but you’d also have to change the baffling too. The cooling system changed completely between ‘52 and ‘53.
Miles
“I envy no man that knows more than myself, but pity them that know less.”
— Thomas Browne
“I envy no man that knows more than myself, but pity them that know less.”
— Thomas Browne
Re: Cowling compatibility
My thinking as well. The early versions had the internal cylinder wrap around baffles and the sealed area is located at the front by the cowl by the two inlets. On the later models (with no internal pressure covers) it seal up tight against the rear where the accessory case mates to the engine. As long as the new cowl fits the same near the front it would make no difference? Not sure...cessna170bdriver wrote:I’m fairly sure the newer cowl would fit the airplane and engine, but you’d also have to change the baffling too. The cooling system changed completely between ‘52 and ‘53.
Re: Cowling compatibility
Sealed area at front.
Re: Cowling compatibility
Does anyone have a picture of the later versions they could share?
Re: Cowling compatibility
The IPC would illustrate it fairly well. You’ll need that IPC if you plan to do this conversion anyway.
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons.
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons.
Re: Cowling compatibility
I have both IPC’s. I guess I didn’t ask correctly, as long as both cowls close off the airflow at the front either will work. Just wondering if anyone has done this before.gahorn wrote:The IPC would illustrate it fairly well. You’ll need that IPC if you plan to do this conversion anyway.
Re: Cowling compatibility
Cessna did it...Poncho73 wrote:I have both IPC’s. I guess I didn’t ask correctly, as long as both cowls close off the airflow at the front either will work. Just wondering if anyone has done this before.gahorn wrote:The IPC would illustrate it fairly well. You’ll need that IPC if you plan to do this conversion anyway.
(can’t find that smartazz emoticon).
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons.
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons.
Re: Cowling compatibility
OK, got it. I’m going to see a 53 barn find tomorrow. We will see what that brings.gahorn wrote:Cessna did it...Poncho73 wrote:I have both IPC’s. I guess I didn’t ask correctly, as long as both cowls close off the airflow at the front either will work. Just wondering if anyone has done this before.gahorn wrote:The IPC would illustrate it fairly well. You’ll need that IPC if you plan to do this conversion anyway.
(can’t find that smartazz emoticon).
- ghostflyer
- Posts: 1395
- Joined: Mon Apr 21, 2008 3:06 am
Re: Cowling compatibility
The original 170,s and 170a all had the plenum chambers over the cylinders and the later 170b,s went to the pressure cowl.
I had a 170a with the plenum chamber and couldn’t wait to go to the pressure cowl when I fitted the 4 banger. That was a big mistake . The plenum chamber is the most efficient system . In the end I have rebuilt the plenum system and fitted the plenum in a form . It’s the most efficient system. It proves that I make mistakes .
I had a 170a with the plenum chamber and couldn’t wait to go to the pressure cowl when I fitted the 4 banger. That was a big mistake . The plenum chamber is the most efficient system . In the end I have rebuilt the plenum system and fitted the plenum in a form . It’s the most efficient system. It proves that I make mistakes .
Re: Cowling compatibility
Just like my 48, I would leave the plenum system too.ghostflyer wrote:The original 170,s and 170a all had the plenum chambers over the cylinders and the later 170b,s went to the pressure cowl.
I had a 170a with the plenum chamber and couldn’t wait to go to the pressure cowl when I fitted the 4 banger. That was a big mistake . The plenum chamber is the most efficient system . In the end I have rebuilt the plenum system and fitted the plenum in a form . It’s the most efficient system. It proves that I make mistakes .
- Bruce Fenstermacher
- Posts: 10318
- Joined: Tue Apr 23, 2002 11:24 am
Re: Cowling compatibility
The last year for the internal plenum was the '52 B model.ghostflyer wrote:The original 170,s and 170a all had the plenum chambers over the cylinders...
CAUTION - My forum posts may be worth what you paid for them!
Bruce Fenstermacher, Past President, TIC170A
Email: brucefenster at gmail.com
Bruce Fenstermacher, Past President, TIC170A
Email: brucefenster at gmail.com
Re: Cowling compatibility
Bruce is correct, of course. The ‘53 B-model introduced the pressure-cooling cowling and improved cabin heat/ventilation. (And after SN 25612 changed the gear-legs to the handed “lady legs”... no longer interchangeable left/right.)
It is arguable which cooling system is better. Cessna never went back to the previous.
It is arguable which cooling system is better. Cessna never went back to the previous.
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons.
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons.
-
- Posts: 3481
- Joined: Sat May 06, 2006 6:05 pm
Re: Cowling compatibility
To get back to the original question, you may be plowing new ground here. I don’t recall anyone saying they have done it and Cessna didn’t ever mix pressure cowls and plenum cowls as far as I know, it was either one way or the other. The first thing to check would be if the pressure cowl has the same screw pattern where it attaches to the boot cowl.Poncho73 wrote:The cowls on my 48 are fairly worn and almost beyond economic repair. I have a set of 53 cowls, they are slightly different. Question, can they be switched out and is that approved? Yes the 53 has both access doors on the upper cowl.
I don’t see why you couldn’t leave the plenum in place and install a pressure cowl as long as you get a good seal around the intake area up front between the plenum and pressure cowl. If you leave the plenum in place and use the pressure cowl, make sure there is no interference between the two which would rub holes in one or the other.
The pressure cowl uses a different rear bulkhead than the plenum but if you wanted to change out the entire cowl/baffle system it might just work.
Approval is another issue I can’t reply to. It might be like changing landing gear, either style is ok?
Richard Pulley
2014-2016 TIC170A Past President
1951 170A, N1715D, s/n 20158, O-300D
Owned from 1973 to 1984.
Bought again in 2006 after 22 years.
It's not for sale!
2014-2016 TIC170A Past President
1951 170A, N1715D, s/n 20158, O-300D
Owned from 1973 to 1984.
Bought again in 2006 after 22 years.
It's not for sale!
- ghostflyer
- Posts: 1395
- Joined: Mon Apr 21, 2008 3:06 am
Re: Cowling compatibility
With my STC for the 4 hangar there isn’t any mention of change of cowling but there was A kit of baffles to be fitted .they had to be modified slightly due to engine differences. Both the baffles and plenum chamber work well. I have had issues with the regulator on this as they are under the impression the plenum should go . Ok show me the paper work where it says I have to. Gee, I love the rules when they go my way.