![]() |
This is a really good thread. C'mon, there must be more engine baffle pics out there. Don't be shy. Yes, I have an ulterior motive. Guess what I'm working on right now... Redoing the forward baffling and seals near the inlets on my -6.
|
I looked at the pictures Dan posted showing some issues with the baffling on that RV. From looking and the narrative, I would think the plane would overheat so bad and have so much drag, it wouldn't fly. Yet, it does. In fairness, the cowling was off for some reason.
It is either a testament to the design of the plane or engine - or both. Im working on my baffling and plenum now and so paranoid about holes and air leaks, it is driving me nuts. I worry about cooling so I guess it is a good thing to go nuts this time! I have a James cowl and BillL built a beautiful plenum for me. I have everything going for me possible so hopefully I will stay cool enough. I will get some pictures posted. In my opinion, it is looking pretty good. |
Enjoy the critique on that plane at the fly-in. What's the "proper" way to do this area, assuming the incorrect way is published somewhere and that's what so many people are using?
|
Inlet baffle seals
I'm also looking for the right way to do this - the instructions are very vague in this area, and if there is an obvious right way that's tried and tested, I'd like to use it.
|
Looks good...
It would be really nice to see some pictures of how you dealt with the inlet transition and ramps... My CHTs are running a little higher than I would like and this is where I have trouble visualizing exactly what to do... Quote:
|
Quote:
There's a natural tendency to think of inlets as a choke point, the narrow passage in the Bernoulli tube illustration...high velocity, low static pressure. It isn't so. Just for fun, carefully add up the measured area of the passages between the fins on your cylinders. My 390 cylinders only total about 23 sq inches of flow area, all four together. Add 12 for the oil cooler scat hose, for a total of 35. The inlets total 56.5. The exit is about 30 in cruise configuration, and about 46 in slow mode. Radical example? Maybe, but again, go measure some Van's inlets. They're all fundamentally external diffusion, Vi/Vo <1. For sure, none are Vi/Vo greater than 1, which would be required to drop static pressure below freestream static at a point aft of the inlet plane. Quote:
|
Well, I'm not sure mine qualify for the thread's title...
I added fillets to the lower outboard inlet areas: These baffle seals have 1540 hours, no meaningful wear: A little wear on this: Years ago, I rigged up a manometer in the cockpit, and calculated that I was getting nearly full pressure recovery on the top. I run very cool cht's and oil. CHT's with OAT of 60F at altitude might be around 320F at a power setting of 8gph, KTAS 168 or so. |
Inlet baffle seals
Thanks Alex, those are probably the most clear pictures of the way to do the baffles around the inlet that I've seen, and clear up a lot for me.
|
Mr. Peterson said:
Years ago, I rigged up a manometer in the cockpit, and calculated that I was getting nearly full pressure recovery on the top. I run very cool cht's and oil. CHT's with OAT of 60F at altitude might be around 320F at a power setting of 8gph, KTAS 168 or so.[/quote] Do you have any data? Does your "full pressure" mean the dynamic pressure at the speed you were measuring? mjb |
| All times are GMT -6. The time now is 07:30 AM. |