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RV-12 I have real heat

JBPILOT

Well Known Member
I spend maybe 10 hours designing and building a Heater Damper Door and Control. See the pictures for proof of how it works. It was 5 - 7 degees on the ground when I took off this morning. Warmer at altitude. About -3 C at altitude. I was dressed warm, but I had to turn the heat down - SERIOUSLY, it was getting very warm inside. The door effectively blocks off about 90 - 95% of the air flow thru the duct when fully closed. I offset the door slightly so it wants to open itself, not close itself. The detents in the choke cable barely hold it, but does. Works FANTASTIC ! Very happy with it. Takes some serious work to design/make the plate ( door ). I have many more pictures.

John Bender

RV-12HeaterDamperDoor100_1327.jpg

RV-12HeaterDamperDoor100_1346.jpg

RV-12HeaterDamperDoor100_1342.jpg

RV-12HeaterDamperDoorTesting100_136.jpg
 
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I'm not sure about the RV-12, but I suspect it's similar to the other models in one respect. That is...the true test of your heater's performance is on an overcast day or at night (not a factor for most -12 drivers). On a sunny day my heat has always been more than adequate because of the "greenhouse effect" of the bubble canopy. I've found the sky condition to be much more pertinent (within reason) to a comfortable temperature in the cockpit than OAT.

Looks like you made some really good improvements to your heat setup in the -12.
 
Great work John! That looks like a great mod. I like the ability of being able to control the airflow in the air rather than using cover plates that need to be adjusted for temps.

I even have a name for your invention........ The "RV-12 Bender Baffle".
 
Thanks Larry !

I usually don't think about flying when it is BELOW 10 degrees on the surface, but I finished the mod Tuesday, and wanted to try it under the VERY COLD conditions. It is very simple. Just pull the 'choke' cable out until you get the water temps up to 200 - 210, and you will get REAL heat from the 'heater' system. There is still a good air-flow, so the warm air coming into the cabin is flowing nicely. I am hoping that in the full open position, it will not restrict air-flow enough to require it to be removed in the summer. I made it for easy removal, so not a big deal. I can not tell you how happy I am this project worked as planned, 1st time. Now the Reiff preheat keep the engine warm over night, and the oil therm quickly warms the oil, and I can have great heat now also. It now is a plane for all seasons ! ! ! !

John Bender
 
Last winter I was constantly playing with adding different sizes of baffle plates to the radiator to get the temps right, but it was guess work at best. This winter I wanted the "Bender Baffle".

The -12 was down for annual, and I just sent the Dynon back for updates and repairs so I bit the bullet and did it! Pretty simply to design and install following John's lead and his suggestions as I was building it.

I can't wait for winter and -15F so I can try it out! :eek:

Thanks John Bender for pioneering and engineering the "Bender Baffle". It sure looks like it is going to work great!
 
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Must have been real cold the day John took the pictures. Did you guys/gals notice the fancy boots John had put on the day the picture was taken??

$5.00 from Farm & Fleet!!
 
$5.49 - - - -

But who's keeping track ! Thanks guys. Yes, when it is near ZERO, I wear Snowmobile Boots ! They also work well !

John Bender
 
NO - - -

It was on there to start with to keep it from falling out, but I just had not taken it off when the picture was taken. Not there now !

John Bender
 
Nice idea John.

I have a couple questions and a comment.

What percentage of the plenum is the door able to block?

Do you notice any change in oil temp when you adjust the amount that the door is closed?


It is very important with a control door such as this, that it fails open. I.E. that if the $10 control cable ever fails, that the door doesn't go full closed and cost you thousands of dollars in repairs because of an over temped engine.
 
Great questions Scott

I offset the hinges to be sure the door wants to try to open itself all the time. The detents of the cable are just barely able to hold it in place. I also designed the oil therm system. The oil stays a uniform temp regardless of how much air is forced thru it.

I would say the max restriction is 95%. When it is 10 - 20 degrees F outside, you have to really reduce the airflow a bunch to get it to actually warm up. It was a very pleasant thing to find out that once you have it set for the temps you are flying in, you don't have to adjust it during different speeds of flying. When you pull back the throttle to land ( and creating less engine heat ), less air is forced thru, and helps keep it about the same temp. Very little variance once set for the days temps.

In cool or cold climates, this really adds comfort to flying. As maybe mentioned above, slowing the airflow down with the damper door, also helps warm the air because it is not rushing thru the rad. so fast.

Really works very well.

John Bender
 
John,

Been following this resurrected thread since I have been putting away the summer toys and thinking about what is coming up here in New York's Mountains. As you will recall, I am putting the finishing touches on N37JP. Starting to think about your mod. Suppose I dare not do it until after certification, but am very interested. Do you have more detailled pictures etc. or will I have to wait until I see you at OSH next year?

John P.
 
Hey BigJohn

Not sure what other pictures would really help. You can pretty much see all the parts in the few pictures. I have stops on the top you can see. I used 1/2" steel washers for bearings, and 1/2" alum shaves for the pivots. Just used cardboard for a pattern. Did not want a precision fit. Just fair. I have 1/8" to 1/4" gaps around the perimeter. In cold weather, you really need to have 90 - 95% reduction of air, or you won't get the collant warm. 200 - 210 is great for creating good heat. Sealing the canopy is essential also.

John Bender
 
John,

Does the curved side of the air dam swing forward for normal weather flight?

Getting ready to install your "Bender Baffle"....my water temps are running low up here in Idaho😎
 
Thanks for asking - -

The outer curved part of the 'door' moves rearward as it opens. I offset the pivots so if the control wire broke, the door opens. I used it yesterday and today on Flyouts. Yesterday it was about 10 degrees at 5500'. Very nice warm air comes out if you force CHT's up to 200 - 210 degrees. For overall comfort, the best mod I have done, for colder climates.
 
It is a nice mod

I also have the Bender mod and added a controllable shutter over the oil cooler. I get plenty of heat at -10 deg on the ground, with the Bender Mod it is warm enough.

With every thing closed i can keep the CHTs up in the 230-235 range. :)
 
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Just a comment - -

I believe it was LEAF that told me the actual coolant temps run 10- 15 degrees less than the CHT's, at least in the older 912's. With a pressure cap, you could get the coolant up to 215 without boiling. A little too much for me, but if you get that high, the air coming out is like a good car heater. it really gets warm. If you have the canopy seals in very good shape, and the coolant temps that high, you will be very comfortable. I also put a clear vinyl 'divider' just behind the seats, and it keeps the cool air from moving forward on your legs and elbows.
 
Another hint, if the Bender damper is installed.....
Change the yellow band CHT setpoint to show a yellow CHT at 210 degF. Makes it noticeable.
 
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