PA-12 cabin heater box and other firewall forward jobs :)
- Thread starter Philly5G
- Start date
It is pretty easy to start with the stock ones and use the aluminized tape to adjust/test than make changes after a year or two of test flying. Everything effects the temps, carb, exhaust, timing, prop, altitude, speed, ambient temps, ect. I tried to roll the top edge of the ramp so it would encourage air to follow down between the front fins. Stock baffle had just a simple vertical bend.
DENNY
DENNY
Wow!!!! Thank you for all this Denny!! It’s REALLY helped me to put this stuff into perspective and made me realise it’s an experiment and not either/or thank you [emoji106]
Couple of questions please; how far back does the level part of the front baffle go? And how far round the cylinder does the rolled top edge vertical baffle go and have you got both the inner and outer intercylinder baffles? [emoji41]
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The front baffles on a cub sit higher than the original one in you picture it go's back to the head and barrel fins. Do a google search and you will see what they look like. Most cusbs have an upturned area in front of the head, and flat back to the barrel. The rolled edge is just 3/8 -1/2 lip kind of an afterthought as I was making them. Intercylinder baffles are similar to yours. I use the RTV to help seal any open areas but like I said do not get it between the fins. Red will get you off the ground 15ft sooner than black RTV
Found some pics of original baffle and first flat front upgrade.
DENNY
Found some pics of original baffle and first flat front upgrade.
DENNY
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skywagon8a
MEMBER
SE Mass MA6
This can be attributed to the angle of the butterfly valve in the carburetor and the swirling action of the fuel/air mixture downstream in Lycoming engines. With partial throttle there is uneven F/A distribution to the cylinders. With full throttle the F/A mixture is more evenly distributed among all the cylinders. Thus you will see the temperature differences between #1 & #2 vary when compared to #3 & #4 between partial throttle positions and wide open.
This can be demonstrated by observing the relationships of the EGTs at low altitude. Then above 5000 feet when the throttle is wide open to maintain the same power setting. You will notice that a different cylinder's EGT will peak first.
Thank you Wayne, in conjunction with the further research I've done and later replies in the thread, these pics have become really really useful
In the 3rd pic, it's looking like the rear inner under cylinder baffle's tie rod is connecting directly to the front baffle's curved under cylinder baffle and the tie rod is basically going between/under the cylinder fins?Also, in the heat shroud pic, one of the connecting adapters is angled beyond 90 degrees, does this affect the airflow much, from the speed and volume angles? If not that will be great news as the cabin heater box I'm about to (re) install is very near the heat shroud and the scat tubing is struggling to make the bend
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So is that tie rod bypassing the standard Lycoming intercylinder baffle and just linking the front and rear baffles?
These pics do seem VERY much the setup of my buddy's PA-12
at last all is becoming clear!! I've found an MGL 4 channel CHT/EGT gauge and also now know that the O235 is equipped with a thermocouple fitting :roll: which means I wouldn't have to modify the HT grommets to route the gasket fittings I was expecting!!WOW!!!! THANK YOU for these Steve!!! These are pretty much exactly the clean, fresh and well-ordered look I'll aiming at!!! I'm loving the pic of the straight fitting HT leads being routed via the Rocker cover bolt clips, that's answered Question #3 PERFECTLY!!!
I can see the heater box is mounted pretty much the same place on the firewall as mine/the standard one(?) but what is on the other side of the firewall? Just a single hole that the hot air blasts through? or some kind of tubing setup to distribute the heat?
The baffles look fantastic, what kind of material is the non metal stuff?
Thanks again
Thanks again for these pics Steve, they’ve been a brilliant resource to refer to
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5+ days of hard labour, shaping, fitting, assembling and disassembling and the front baffles are finally ready for riveting and then powder coating :roll: Thank you to Tony Bingelis for the base paper templates and everyone who contributed to this thread and messaged me about baffles production. Let me ask a favour of you all, if you ever see me saying the words "baffles" and "making" in the same sentence, please just shoot me there and then............
I do have another question to ask though. I want to split the airflow from the starboard air intake, most of it to go into the Heat Shroud to power the cabin heater and the rest of it to be siphoned off and into the generator for cooling. I'll have a 2" Scat tube on the back of the intake fitting, is there a way to somehow siphon off a smaller tube from the Scat tube? Or do I need to source/make a metal tube fitting to go inline with the Scat ducting and have an air scoop in that to go to the smaller diameter generator intake? I'll be really interested to see what others have done in this scenario
I do have another question to ask though. I want to split the airflow from the starboard air intake, most of it to go into the Heat Shroud to power the cabin heater and the rest of it to be siphoned off and into the generator for cooling. I'll have a 2" Scat tube on the back of the intake fitting, is there a way to somehow siphon off a smaller tube from the Scat tube? Or do I need to source/make a metal tube fitting to go inline with the Scat ducting and have an air scoop in that to go to the smaller diameter generator intake? I'll be really interested to see what others have done in this scenario
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mike mcs repair
Registered User
chugiak AK
You could “glue” scat into other. I did a test with silicone mold making rubber(2 part). There’s probably some glue out there? Anyone got a link. I see spruce sells something for gluing baffles.
And if you just need standard baffling http://www.airforms.biz
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And if you just need standard baffling http://www.airforms.biz
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I like the gluing/welding idea! Does anyone have any photos/examples of this in action?
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Inspired by this idea [emoji1303] I’m going for a collar around the Scat and an angled 7/8 tube through it and the Scat tube, linking via 7/8 Scat tube to the generator
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skywagon8a
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SE Mass MA6
Philly,
Usually the brush cover plate on a generator has a short tube built into it for venting purposes. This cover plate is rotated to align the tube with an opening in the cooling baffle just above the generator. Then the ram air entering the right nose cowl opening blasts directly into the generator. There is no added tubing required. This opening is located in the lower inboard aft corner of the baffle next to the crankcase.
Do you have a generator or alternator?
Usually the brush cover plate on a generator has a short tube built into it for venting purposes. This cover plate is rotated to align the tube with an opening in the cooling baffle just above the generator. Then the ram air entering the right nose cowl opening blasts directly into the generator. There is no added tubing required. This opening is located in the lower inboard aft corner of the baffle next to the crankcase.
Do you have a generator or alternator?
Generator. The original flat baffles allowed air to flow under the front cylinders and would have had SOME effect on the Generator vent tube as you say. However, the vent tube was pointed vertically downwards [emoji849]
The new baffles are the ramp style and the airflow would now miss the gen vent, even if it was correctly aligned, as it now is, hence ducting the ram air directly to it [emoji41]
I did consider adding an additional inlet hole to the baffle for the gen cooling, but decided on the single intake and splitting off
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BRILLIANT!!!! Thank you Wayne!! I KNEW I'd seen a photo somewhere of a smaller Scat tube teeing off the air intake on the Starboard Cowling baffle but COULD NOT remember where it was and HERE it is!!!!! Picture 3 is EXACTLY what I'm doing, but the teeing is slightly downstream of the Scat, but doing EXACTLY the same thing!!!! I'll post a pic when it's done. Thanks again
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BRILLIANT!!!! Thank you Wayne!! I KNEW I'd seen a photo somewhere of a smaller Scat tube teeing off the air intake on the Starboard Cowling baffle but COULD NOT remember where it was and HERE it is!!!!! Picture 3 is EXACTLY what I'm doing, but the teeing is slightly downstream of the Scat, but doing EXACTLY the same thing!!!! I'll post a pic when it's done. Thanks again
Thanks to everyone for your help in this thread and project!! Here’s what I ended up with with the cowling baffles and SCAT Y connector
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