It's Baffling
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- čas přidán 8. 07. 2024
- A complex set of rigid baffles and flexible baffle seals are critical in keeping your engine cool. In this webinar, engine guru Mike Busch explains how the cooling system works, and discusses how to diagnose and correct cooling system problems. Mike illustrates this with a real-life story involving a Cessna T210 whose frontmost cylinders always seemed to have higher CHTs than the others, and how Mike helped the owner cure this problem with the help of some smartphone photos. Savvy Aviation offers Professional Maintenance Services to owners of General Aviation aircraft, such as: SavvyMx (Professional Maintenance Management), SavvyQA (Expert Consulting), SavvyPrebuy, SavvyAnalysis (Engine Data Analysis) and Breakdown Assistance. Savvy also publishes a monthly newsletter with lots of interesting information for the general aviation enthusiast; subscribe to it at www.savvyaviation.com/home/ge.... For more information, visit us at savvyaviation.com. This webinar was hosted by the Experimental Aircraft Association (EAA).
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working on my CFI lesson plans and this is incredibly invaluable information. thanks for the great work!
I can’t believe I’ve called a few guys telling them my 5-6 cylinders are getting hott and nobody knows. First 5 mins mike says why in this video, now I know what to look for.
Thank you for all the work you do, opening our eyes to some truth in GA!
I had a new cowling put on my E model Mooney. Afterwards my cylinders were running much hotter. When I descended it would even get worse! I noticed that the new baffles were folded the wrong way. I couldn't believe it could make that much difference but took it to my Mooney specialist and he cut me new wider baffles and that solved the problem. I told the shop who sold the cowling that his baffles were to short but he said that it wasn't the problem. But me and my mechanic knew better.
Thank you sir for posting. Excellent video!
Thanks
Thanks, another well-made webinar. It took me a long time to understand how this works, and why it is better in almost every way (except structural weight) than hanging the cylinders "out in the breeze". One thing in subsonic flows that people find counter-intuitive is that by widening the intake after the inlet opening, the air flow will slow down, and pressure will increase.
I have zero mechanical skills, but this really helps understand systems in a clear but still detailed fashion. 👌
I was waiting for the A&P to finish up my annual paperwork a few years back; while I was waiting I walked around the hanger looking into the cowling openings at the baffle seals (this was an issue I had been working on my 172P). Every aircraft that I looked at (mostly 172's, a couple of 182's, etc) had the seals backwards (pointing toward the lp side of the baffles). The reason I was aware of the issue was I had installed an engine monitor as part of a panel upgrade and had been chasing CHT issues ever since.
Thanks it was very interested video
Thank You
You're welcome
Those baffle wears out due to heat, vibration, but I wonder how long the longevity is , how many engine hrs, also depend on hot climate or cold climate, I wonder, Mr savvy, thank you for all these knowledge training
Hi Mike, great presentation! Question is can you explain about having a good Cowl Chafe Seal please. What’s does it do for the plane if in terrible shape and when changing it out to new what then to expect? Thanks Mike, love all these informational talks
As soon as you said audiobook I bought it! I can't stand reading long books! Thanks
HI ya Mike, another good.open your eyes video, Early Az Trks. Had felt inlet cowl baffling, oh in that 210 pic left bank center bttm plug wire on my picks like a rodent got.to it..Happy New yr Mike & all of you
Great presentation for pilots to understand.., I never really understood the concept!
Glad it was helpful!
Good information. Thanks for posting this.
I do have an off topic question. I often watch automotive repair videos. A couple of channels use what I would call advanced diagnostic techniques using tools such as oscilloscopes and pressure transducers to diagnose automotive engine problems. I was wondering if you had ever looked into these techniques and their applicability to GA engine diagnosis and maintenence. The channel Automotive Test Solutions probably has the best example of this type of diagnosis. Scanner Danner is another channel. I am sure there are other that I am not aware of.
Hello Mike, i have a piper cherokee and the oil temps get quite high ( top of green)in the summer and right now in winter months my oil temps are 200F plus and 30F ambient OAT. Is it possible to see a normal cylinder head temp 300F and still have those high oil temps? Are they not related? Thank you for your videos. Really enjoyed the one about leaning.
I have a Cessna 150 1972 model. What about the baffling that goes around the air filter assembly. Most of the 150s I’ve ever looked at including mine this is missing. Will this affect the low pressure side of the air chamber and affect the cooling.
Piper Tri-Pacer 1960 used 1/2” thick felt stapled to the aluminum to interface with the cowl.
Replace the felt with silocon shown in the IPC. Your A&P is required to do this repair work. Where's he been ? A&P noted.
Shock cooling almost requires intent. Many hours flying a C-182 jump plane without ever cracking a cylinder. Climb is at 80 Mph, 2450 square, hold CHT to max 390. One minute prior to jumper exit reduce prop to 2,200 RPM, half minute prior to exit reduce MP to hold altitude typically 18 to 20 inches. After exit close cowl flaps 30 degree bank 140 MPH airspeed. As CHT drops, reduce MP to 13 to 14 inches, increase airspeed to 150 to 160 Mph. Fairly aggressive procedure, never a problem.
Ambient air temp? Rental 172 at home airport in Wisconsin I know used to not rent the plane if ground temp was below 10F
I fly a Robinson R44 which has an IO540 mounted backward behind the cabin. Cooling air is provided by fan mounted to the crank shaft. And the airfow is similarly top to bottom. I'm wondering if deltaP is of the same magnitude in this setup? We noticed the CHT got higher recently and after watching this video, I found a gap in the baffles which was probably introduced at the last 100hr. Will get this corrected but wondering if a fan pressurized setup has the same sensitivity to gaps.
The Velocity XL is a pusher canard. How would you cool a 6 cylinder for that plane? Often see NACA ducts on top. Is it safe to assume the air exits the cowl alongside the prop shaft and the baffles allow air only to pass down over the cylinders along the bottom and out the back? Is flight speed and any pull from the prop enough to create the pressure diff? Any ideas to maximize cooling in this plane?
Would it help to make the birds nest of hoses and tubes on top of the engine more aerodynamic? This would reduce pressure loss and cooling drag. I’m thinking of oval or teardrop covers on the tubes and hoses or gathering them up or rerouting them. You would never leave that mess hanging in the breeze if it was external to the aircraft.
Also, what is the typical airspeed between the high pressure and low pressure plenums?
That would help a bit, but probably not enough to worry about, since the flow through the cowling is slow compared to freestream velocity outside the cowling. Shaping the air inlets and making the first few centimetres of air duct very smooth to recover as much ram air pressure as possible helps a lot more. Having a more efficient pressure recovery lets us get away with much smaller holes, reducing cooling drag even further. Look at the difference in intake size and shape between an Archer II and an Archer III, or, even more pronounced, between a Socata Rallye and a Socata TB series, to see the progress.
Unfortunately the problem with the baffles is aerodynamics matter in pressurized areas like under the cowl on top of the cylinders, where not a single engineer has designed the area to be pressure flow efficient. The result is the design fails to cool the last two cylinders because of the engine clutter, choke points and poor aerodynamics.
36:52 they are simply called baffle Fastners if you type them into Aircraft Spruce
Google “Book Binding Nuts”. There are several sizes available on Amazon..
Thank You. Whoudda known?
I wish I could've asked while live:
Is there a reason why the tops of engine compartments are the high pressure area, and bottoms low?
I would think that having the inlet at the bottom would increase deltaP, providing more cooling at high AoA, which is when aircraft are usually operated at higher power settings (and need the cooling)
as a minimal effect, convection should increase airflow, and cowl flaps could open to add heat to the outside of the windscreen as a free cockpit anti-ice.
Mike, do you check the comments section of YT? Or should I send an email your way?
For the question on measuring deltaP, I'm pretty sure HomebuiltHELP posted a video on it like 3 weeks ago
Speculating here...have you noticed what a mess an airplane's belly is just behind the cooling outlet? At least some of that crap would probably end up on the windshield if the flow were bottom up. Note that the one example cited in the video is a twin.
@@jjohnston94 I think most of that crap is due to two things:
1. The exhaust is aimed down, and although it usually extends an inch or two beyond the body, the exhaust produces soot that gathers
2. (More probably) the oil breather overflow drips oil over the cowling. Mike Busch discusses it in a different video, but it's related to how heated oil expands, and aviation engine usually dont have the (condenser?) That takes that oil and puts it back into the system that most automotive engines have had for decades
Peter Garrison of Flying thought the same thing and incorporated updraft cooling on his home built, Melmoth, 30 or 40 years ago. It takes advantage of the inherent pressure differential between the upper and lower portions of the aircraft. Wikipedia states : “The engine is cooled using updraft air which enters through a single inlet below the spinner and emerges from the top of the cowling near the spinner.” Exhaust exits below, and since most oil mess comes through the exhaust, the windshield stays clean. It does expose the windshield to oil and debris if the engine leaks or comes apart and to heat if there is a fire. He designed the aircraft himself. He was an English major.
I wish I had caught this one live. What is an owner allowed to do with the baffling on certified? Change flex seals, rebuild the baffle system, modify etc.?
An owner is allowed to do nothing. A certified mechanic is allowed to replace the soft seal. A certified mechanic is also allowed to stop drill any cracks and make minor repairs. Changing the baffle system away from its original Design in anyway is considered an alteration which requires approval from the FAA. And they don’t give approvals for that stuff very easily. I hope that helps
Thanks. The video made it sound like you could do some stuff without signoff. May have been aimed at experimental at those times.
A&P work. An owner can if mechanically inclined, A&P help. Owner needs knowledge of his airplane.
Plug holes with RTV...
My baffles are too good most of the year, i struggle to run 320-330F LOP, even ROP it is only 5 degrees higher….i want to up the temps at cruise by 40 degrees. What is the easiest way to do this? If i cover the oil cooler i wil trade this for oil temp? HELP, my engine is 20 hours old, I want to bet ahead of this as my prop stroke/900 hour engine needed a Full OH due to spalling and valve issues…maybe caused by me be fat dumb and happy at 300-320 LOP
Not to be alarmist, but isn’t it a problem if we have aircraft mechanics who “don’t really understand” how something works? If you have a non-savvy, or at least trusting owner, I can’t see it ending well, depending on the particular system that the mechanic “doesn’t understand”.
Colin, A&P here. All, all, aircraft are different, " Women ". It's not a simple job, an d with the owner ready to fly now !! Spent 60 years business GA, military, retired, and single. In military, AC, " hanger Queens ", always broken, other AC always flying. AIR FORCE school airframe, powerplant, total 18 systems, 18 months. FAA license, testing, knowledge 80%, pass. Logbook signoff repair, AC is Airworthy to fly, IAW FAA. Crash, A&P is ?????.
@@chuckhiggins15 It wasn’t a blanket statement. It just seems like something gets missed along the way in some mechanic’s training, and if there isn’t another set of eyes to catch a problem, be it the owner or a supervisor, there’s potential for problems. This is true of many different trades as time goes on.
why don't you guys bring parachutes with you so if the plane is going down you jump out and float to the ground. : ).
😢❤😅😅qqqq❤❤😮😮people who are ¹E
😅w
This was not informative. Lost of us are builders, and are looking for the fundamentals of designing. Not "make sure you don't have leaks". Thank you for trying though. Looking forward to a more indeapth presentation.