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RV 10 door fitment

Weefle

Weefle

Well Known Member
I’ve been fighting with these doors and am looking for advice.

I have the McMaster door seals, plane around latch and pins etc.

When I go to close the doors I have to reef on the handle to get it to latch. It should not be this hard. I’m afraid of eventually breaking something.

Even when I take the seal off it’s still tight. I’m thinking of enlarging the holes for the pins slightly where they settle in the holes in the fuselage frame.

Any other suggestions? What am I missing here?


Thanks

Keith
 
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If it’s still tight with no seals installed then something must be binding somewhere.
With no seal the door is clear of the entire cabin structure around its perimeter by around 3/16-1/4”
The pins should engage easily in this scenario.

It can get tight with the seals installed. In this scenario you should boelube the pins and also make sure that the chamfer in the pins are angled as to pull the door down and inwards as it engages.

Don’t enlarge the holes. The doors will then just sit proud of the fuselage.
 
I considered the doors to be one of the most iterative jobs on the whole build. I think fibreglass, by it's very nature, is always subject to lots of fitting, sanding, grinding and adjustment. Now you're laminating two pieces together and trying to make it mate up with another piece - that being the cabin top.
Hopefully you've gotten the alignment of he hinges correct. Check and make sure you have the proper hinge pieces in the proper location and orientation. Its very easy to put these on wrong and that will induce some binding and stiffness in the doors. If that's ok then it's just a matter of fitting, sanding and adjusting.
It will take a awhile and will involve many sessions of sanding, adjusting and even building up but you will get it eventually. I used the McMaster Carr seals and once I installed them the doors were initially very tight and I was worried about something breaking but eventually the seals compressed down and now the doors close with very little effort.
Did you also install the Plane Around third latch? It is a very useful addition and it greatly helps to latch the doors once the seals are on as it has a tapered cam design and really pulls the centre of the doors in to seal.
Oops I just reread your post and see you do have the latch and Carr seals. Try everything without the seals and go inside an make sure you have the clearance all around on the inside. If not - start sanding...
 
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In a nut shell

Try everything without the seals and go inside an make sure you have the clearance all around on the inside. If not - start sanding...
Click to expand...

Your most likely spot that requires more sanding, assuming all other things are installed correctly, is the top lip and around both corners. The slightest pressure in this area will keep the door from closing easily.
For the McMaster seal you need <1/4"> all around or else it will not close without brute force. On the top end there will be almost nothing left of the curved portion of the lip. I know, it seems like you are weakening the door frame by taking that much off and maybe you are.
Others may disagree but I would wait with the grease until the door properly fits and apply some lubricants to the closing mechanism and pins after the plane is painted. It will be a nice "bonus" in helping ease the door locking task.
BTW: The McMaster seals are a really neat looking and very tight seal, it is worth the effort IMHO.
 
Binding

Keith,

A few places to look that may have been mentioned.

Take the aft and fwd door guides off the door.
Is it still hard to move the handle with the door open? Now close the door and guide them into the cabin guides? Is it stiff now? This will tell you if its binding on the door or the fuselage. Make sure pins/pushrods are parallel in travel with the fuselage guides.
Now try taking the cam off (if still held in by the set screw not the roll pin) and closing the door. If it's smoother it could be from squeezing the seal too much or the cam binding on the cabin block. The seal has a 3/8s bulb and can only compress to 1/4 inch no less. So make sure your reveal around the door with the seal off is no less than 1/4 inch all the way around from the outer edge of the cabin lip to the inner skin of the door when it's closed.
Another one I've seen is the cam shoulder can bind against the cabin block if the cabin block is too high; what happens is the angled pins push the door in and down and presses the cam shoulder down into the cabin block. This is easy to fix by sanding the bottom of the cabin block OR relieving the cabin block by sand in a half circle for the cam shoulder to rest on.
 
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Weefle said:
Even when I take the seal off it’s still tight. I’m thinking of enlarging the holes for the pins slightly where they settle in the holes in the fuselage frame.

Any other suggestions? What am I missing here?


Thanks

Keith
Click to expand...

That would imply that either there is binding in the linkage somewhere or, more likely, accurate parallelism was not maintained in either the pin guides in the door or pin receptacles in the frame. When done right, there is not a lot of clearance between the pin and nylon bushing and therefore even a degree or two off on the drilling will make things tight. I would not start by hogging out the holes, but instead identify the exact flaw and use shims to improve alignment. A little bit of relieving with a round pin file in the door receptacle may work, but need to get some crayons out to see where things are rubbing first. First identify tight spot and slightly relieve / rinse repeat. Do not just go in there with a larger drill bit.
 
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Thanks guys for all the replies.

This morning before I left for a road trip I took a feeler gauge and went around the perimeter of each door.

On the pilot door w/o the seal and door latched in place I had no clearance on the bottom of the door. So I’m thinking maybe I’m binding a bit on the bottom of the door to fuselage contact area.

On the copilot door with seal in place I had clearance but as noted earlier it’s a lot of torque on the door to close. So I’m thinking the seal needs to move back.

I have not yet installed the plane around third latch as I want to get this right first.

Next week when I’m home I’m going to remove some of the width of the lip where the seal sits to take out some of the seal crush. I thought I had about 1/4” but I may need .040 or .050 more so I’m not trying to crush the bulb as much.

I will also try some machinists blue on the door pins to see where it’s catching. I know this is a test of patience or something like that.

Keith
 
Check the alignment on the door hinge as well. A problem with alignment on the hinge can present as binding or the doors riding too high or low. One way to check would be to unscrew the hinges on the cabin side, lay it down naturally, and see if the door rests in the opening and the pins can close easily. If so, you need to re-drill the holes on the hinges on the cabin top.
 
Yes

The hinges are NOT the same. There is are two forward hinges and two aft hinges. They are not the same and will definitely bind if installed incorrectly.
 
I recall double checking the hinge orientation as per the plans. Worst case is I disconnect the door side hinges, fit the door with the seals on and close the door engaging the pins. Then check to see if the holes line up on the hinges to door.

Keith
 
On the pilot door w/o the seal and door latched in place I had no clearance on the bottom of the door. So I’m thinking maybe I’m binding a bit on the bottom of the door to fuselage contact area.
Click to expand...

If you have no clearance without the seal, as you stated, it is not a "maybe" as to why your door is hard to close with the seal on.
You cannot get away with less than 1/4" clearance ALL AROUND especially on the top end of the frame.
Without the seal, your door should fall into place for an easy close.
From there it is a restart to include the seal and properly done the door will "almost" fall" into place with a very slight bit of resistance due to bulb pressure.
 
N427EF said:
If you have no clearance without the seal, as you stated, it is not a "maybe" as to why your door is hard to close with the seal on.
You cannot get away with less than 1/4" clearance ALL AROUND especially on the top end of the frame.
Without the seal, your door should fall into place for an easy close.
From there it is a restart to include the seal and properly done the door will "almost" fall" into place with a very slight bit of resistance due to bulb pressure.
Click to expand...

Thanks Ernst……I’m definitely getting good info here to get this fixed!
 
Follow up

So I thought I should follow up as I get annoyed when others post issues then never post as to what they found and fixed.

Here’s what I did:

1. Checked the door frame to fuselage contact. Removed material till. Had a small gap.
2. Checked the door pin blocks to ensure the frame didn’t bind on those blocks when closed.
3. Checked seal clearance to door frame and adjusted slightly by removing more material.
4. Checked hinge orientation to confirm it was correct.

After all this the doors were only slightly better in terms of the amount of torque on the handle to close.
I then thought to grab the bottle of Boelube and put a few drops on the door pins themselves. Much to my amazement the doors were instantly 60% easier to close! I had thought the plastic guides would allow the stainless pins to slide back and forth. Apparently not. Hope this helps someone else who is struggling.

Keith
 
Thanks for the follow up! It's always nice to hear when someone's issue has been solved.
Also reminds me of what someone once told me that sometimes the solution is the simplest and most obvious thing. Now that I think of it, I also used the handy Boelube when I was testing and installing the door latches.
Now you can mark the doors as mostly complete and move on to less tedious tasks.
 
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