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Vent door hinges - page 28-09

JHartline

Well Known Member
How did you guys secure the hinge pin inside the hinge? Shorten the pin and crimp the hinge ends? I don't see anything in the instructions about it so that's my plan.
 
It's been quite a while, but is the hinge not inside the heat box and the pin cannot go anywhere?
 
While you're building the heat boxes, I'd suggest finding a way to seal the flap valve. Right now one of the issues I'm facing is that the heat valves, when all the way off, aren't quite sealing. The floor in the area gets hot and some of the metal gets hot enough that you can't touch it, all just from leaked heat. This is only on one side right now, the other side leaks slightly. It's very hard to get to that area once the plane is completed, so I'd suggest sealing them up well during the build.

Just wanted to throw that in while you were talking heat valves.
 
Thanks Tim

I had been wondering about finishing touches during this part of the build. Seems like the plane is coming together faster which means, as you observed, that some things are much easier to do now.

Last thing I'll need during a Georgia summer is more heat ;)
 
I'm not exactly sure what I'll do but my first attempt will probably be a very super thin layer of RTV. At least that is something I could remove if it doesn't work. I already adjusted my control cable to have a bit more cushion so that it for sure would shut all the way, and still it comes open a bit. If you push and hold the knob in it gets better but not 100%. If the push-pull cables had a little more tension on them it may be satisfactory as-is. I'm just hoping if I do RTV that I can get it smooth enough. I'm thinking of spreading the layer thin on the door and packing tape on the other half, then closing the valve with pressure held on it. Remove the tape after it cures and maybe it'll work.
 
I'm trying RTV

I traced the vent door outline on the front the firewall and masked off around the outside of the lines. That left about 1/4" between the tape and the edge of the hole. Then I covered the door with electrical tape. A thin bead of RTV around the hole and I clecoed the door in place and squished it into the sealant. I rigged up a little weight to hold the doors firmly against the firewall/sealant bed. It will be a very thin layer. If it don't work out I'll peel it off and try something else.

Unfortunately I won't be able to report on the results for a few months when it actually flies. Well...hopefully just a few months.
 
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My solution for a better heater vent flap seal is to place shims under the lower part on the hinge. When the hinge is cleco'ed in place you can see that the thickness of the door causes the base to bind therefore making it difficult to make the top seal (it will seal but requires some amount of force).

So I took some .005" stainless steel and folded it over three times. Once I drilled two holes in it, the thickness allowed the door to close and seal easily with no force. Only time will tell if this works but all indications say it will.
 
I should say that since I upgrade my heater control cables to the pushbutton locking style per the other thread, I no longer think I will need to do anything additional to seal my heater vent doors. Now that I can put pressure on the cable and it locks in position, I not only have vents that seal better, but when using them partially open, they stay at the position I intended. I would highly recommend now that people just do not order the 2 black cables that come with the kit and order the replacement ones from spruce. They are A-700 72" controls sold by aircraft spruce as part number 05-13172. You won't regret it, and it'll save you a lot of headache down the road.

Tim
 
ACS cables

Tim - I'm doing what you did. Can't see spending a lot of time re-engineering the vents when the fix is so easy. I'm ready to get this project FLYING. :D
 
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