Club Homepage Forums Classified Ads Buy & Sell - Everything But Airplanes Air Intake Box Frame

Best shown via the photo. I suppose we could fabricate one but it seems a lot of work. [Linked Image]

Referred to as "bracket assembly - cowl snubber" with the assorted baffles.

Ideas welcomed.

Cessna sells that part, as I've replaced mine in the past. The new ones are plastic (and they will crack again) with the 4 baffle seals installed. Last I checked around 5 years ago, they were in the $130 range. I'll dig around for a part number...

Yowza!!!! Looks like they went up a wee bit:

#0452017-15
$521.55

Rethinking here, I wonder if it would be possible/feasible to disassemble it, press it out, straight/flat, scribe another replacement onto a piece of flat aluminum, form it up in a metal brake, reattach new baffle seals and make it an "owner produced part?" Seems it's got to be cheaper than $500+dollars for the OEM replacement?$?$?$

Then again, most '71-'77 models I've looked at seem to be missing that piece.

Glen, this happened to me this past annual, though yours seems a bit worse.

We did a sheet metal repair with the original part.

Check some scrap yards perhaps?

My A&P/IA is considering fabricating it himself but I wanted to check with everyone else before we,started reinventing the wheel so to speak.

My A&P is generally hesitant to fabricate some things because his time becomes as much as just buying the part outright, depending.

I agree. Sometimes it is just more cost effective to buy it from Cessna. I did this for the very aft tail cone sheet metal on my plane. Yes, I could have made one. But by the time I bought the correct sheet of aluminum, then having to experiment on at least 2 or more test pieces to get the correct compound curve. I decided just to give Cessna the $250.00 for the factory CORRECT part.

Mine has been missing since i bought it(8 years ago). At least 60% of the 150's I look at dont have one. I doubt it makes a hill of beans difference to the airflow underneath the engine. My I/A is ok without it being there.

Jim, I kinda like your line of thinking on this.

What my old one looks like, made of some sort of formed plastic, metal baffles, staples and thin, black seals. Made for '71-'77 L-M models ONLY.

[Linked Image]
[Linked Image]
[Linked Image]

It sure would be nice to preserve it, remove the baffle seals and re-engineer it out of fiberglass.

Glen, I'll mail it your way if you need an original to go from while making a new one. It's be fairly easy to scribe one onto a piece of flat aluminum, cut it out, drill it and apply the appropriate brakes.

I'd just ask that the integrity of the original remain intact for future use. PM me your address if you decide to go this route.

Here's what a new one from Ce$$na looks like

[Linked Image]

So where on this is the gold plating? Hard to imagine the cost being justified for some if not all parts from Cessna.

We're going to move on without this expensive bit of baffling and see what happens.

Glen,

I am getting ready to start a run of panels (for a fairly long wait list)...however, if you send that bracket to me, I will lay it out in a CAD file and make you an aluminum one for free...

You will have to paint it and attach the baffle material so it's an "owner manufactured part" ;-)

Cool,

Bill meet Bengie... Bengie meet Bill...

Bengie, how about sending that very nice clean and complete unit to Bill for reproduction!? That way we get the complete picture vs the mess of mine. Also once complete we will have this for other members who may need access to the file.

Is this a great club or what?!?

Kewl, I will probably see Bengie soon; I'll get it from him!

Bill,

You got one in your hangar that only has one crack I believe. We could tape it or glue it up and make a template from it easily I think.

It is my opinion - based on no real scientific evidence - that omitting this baffle is a major contribution to the O-200's reputation for carb ice.

Leaving out that baffling allows pressurized (from outside) ambient air to flow around the filter and then carburetor - lowering the temperature of the body.

Fitting this baffling seals the carburetor in the nose bowl in the warmer air from the engine operation keeping the carb warmer - reducing the chances of carb ice.

--

I also wonder about what it does to the designed air differential pressure between the cowl intake and the exit around the nose gear which an important part of the air cooling.

YMMV

and you lose about 5 1/2 knots

I have not had carb ice in my 150 other than "possibly" 2 times in almost 8 years of ownership Both those times conditions were OPTIMUM for carb ice formation. I dont think that the airflow around the cylinders is affected at all. That air overpowers the small surface area of the filter opening sans baffling easily I would think. Might be some stuff going on turbulence wise at the gear opening, but I doubt it has other than a very minor effect on the flow.

Offset by the RAM air into the airfilter caused by the baffles

The REASON that Cessna added this COWL BAFFLE SEAL around the carb box intake, is because the "L"-models and up have a propeller spacer, and the fiberglass cowls on the L and up years have the cowl further away from the filter frame. They didn't re-design the carb heat box with a longer scoop, they just added the seal assy. to fill the 2-3" gap.

Will there be any major problems with air flow if the baffle seal is removed? I can't see $600 for this piece of plastic and baffling material. I'm missing 1 complete side. Taking it off.

If the baffle frame is removed, then it means the engine cooling will be impaired.

For those who don't know, engine cooling is done by high-pressure ram air entering the cowl through the regular inlets, flowing through the cylinder fins to the low(er) pressure below/behind the baffles, then exiting through the opening in the lower cowl around the nose strut.

The difference between high pressure and low pressure is what drives this cooling flow of air. I seem to think the difference is only 4"-5" of water.

With the baffle around the air filter missing, then it means ram air is (can?) enter the low-pressure side of the engine, reducing this difference and the cooling flow of air through the engine.

How much of a difference? I don't know. But, operating on the theory that "parts left off don't cost or weigh anything and never need replacement," then I would think Cessna would've left it off if they could.

For those interested, here's an article on engine cooling design, and how to make your own, inexpensive, "water manometer" to test cooling pressure and effectiveness.

http://eci.aero/pdf/EngineCoolingProblems-SAE.pdf

Mine has been missing as i said earlier for 8 years. I do not believe it has resulted in any heat issues or cooling problems for me. Anecdotally well over half the 150's I have inspected have been missing this baffle.

HEY!

I just noticed the N number of your plane.

Your bird used to have blue instead of red.

Just thought you might like to know that.

I have been experiencing carb ice problems and some high cht problems on the number 1 and 3 cylinders. i noticed a hole in the carb air box baffling toward the number 1 and 3 side. After reading many articles on carb ice and knowing how the top of the cylinders needing higher pressure than the lower side of the cylinders, makes the possiblility of cowling air leaks even next to the carb air box a real issue. As one person mentioned that the later 150's with a prop extensions require this seal.

Old thread but wondering if anyone eventually came up with the CAD file to recreate the air intake baffle plastic frame? I have been unsuccessful in finding even a beat-up old one to copy so I can do an owner manufactured part.

My C150L is equipped with a JPI900 so I do know what is happening with the CHTs and EGTs. A piece of the frame broke off completely and my CHTs went up. When I can contact my IA I will explore making a part out of Kevlar which I will mold over a wooden block that will be cut to the shape of the inside of the frame.

Aerofairings in Canada has a direct replacement "The A105S150 is designed for the C150M..." and the total cost shipped is $211.15can or about $165.00 USD.

I have just emailed Aerofairings and hope to be able to order immediately.

Am I correct in interpreting the information in this thread as meaning that the air intake frame wasn't part of the original 150 aircraft design prior to the L model?

Roy

Roy, YES. My plane for example, 1970K...has metal nose. No prop spacer. Thus..the airbox fits flush.

So I got the replacement from the folks in Canada, I put longer metal baffles and longer pieces of baffle material and my CHTs dropped 15 to 25 degrees.

TO ME THAT IS A LARGE DROP IN CHTS! !

I cannot comment on the lower CHT temps as I’m not lucky enough to have a gauge but I can say that since I fitted one of these shrouds my carb icing issues seem to have gone away.....6 months and 35hours without a problem. I’m on Vancouver Island in the middle of a wet temporate rain forest with the possibility of high humidity year round. It’s not much fun when the engine coughs at 7000’ over Comox glacier.!

So far, well worth the money....