| Howdy Ya'll! |
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Do what yer' Momma said...
Go Play!
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Any substitute for RTV on rudder stiffners? - View Thread
About to close up the rudder skin and don't have any proseal or RTV. Is there an acceptable substitute available at the local hardware store or Walmart?
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Any substitute for RTV on rudder stiffners? - RE: - View Thread
I'm not sure about substitutes, but most all auto parts stores carry Permatex "Blue RTV Silicone" in tubes that are about the perfect size for the stiffners.
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Any substitute for RTV on rudder stiffners? - RE: - View Thread
RTV is available at any auto parts store, at least most of 'em (Kragen, AutoZone, Pep Boys, etc.). Permatex is the brand that seems to be most common.
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Any substitute for RTV on rudder stiffners? - RE: - View Thread
I bought some RTV at the local Auto Zone - Couple of bucks per tube.
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Caution drilling Elevator Horns(Long, but important) - View Thread
When drilling the elevator horns for the hole that the elevator pushrod connects to there is a potential problem that the instructions don't point out. In the instructions it clearly says to drill the aft most horn first for proper edge distance, then use that hole as a drill guide to drill the other hole through a block of wood or metal to keep everything perpendicular. What it doesn't mention is that one horn could be higher than the other one and this affects the edge distance even more. My aft horn was the lower horn, which I didn't even check for. I drilled the 1/2" in and 3/8" up hole into the left horn. Then clamped my block of metal/wood between the two horns and drilled into the the right horn. When I took the block out, the right horn hole had hardly any edge distance, about half what the left horn had. I thought that I had screwed something up, but after careful examination I notice that the right horn was indeed higher than the left horn. So no matter how precise I measured the left horn hole, and no matter how perpendicular I kept the drill bit as I drilled into the right horn, the distance isn't going to be good, because of the right horn being higher. Also, becase the block is clamped between the horns as I drilled, I couldn't see how close the edge distance was going to be until after I was done drilling. Keep in mind that my counterbalance horns were clamped tight to the stab in the neutral position and my elevators lined up perfectly. I have sent pics to Van's and am awaiting word on the edge distance. My suggestion to other people is that if your aft horn is higher than the other one, then drill as per the instructions. If the aft horn is lower than the other, then measure that difference and add that to the 3/8" that the plans tell you to drill up from the bottom of the horn. There is almost an inch between the bottom of the horn and first lighting hole, so I don't know why Van's has you drill that first hole so close to the edge or why they don't mention the up/down difference in the horns.
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Clearance for elevator horns - View Thread
I note on Vans RV7A drawing no 3 (Horizontal Stabiliser) that it calls for a notch in the lower flange of the rear spar HS-603PP "to allow the Elevator Control Horns to pivot forward and contact the elevator 'down' control stop". But when I look at a whole pile of web sites, including Dan Checkoway (my favourite), I see that this notch has not been cut by many builders during the building of the Horizontal Stabiliser. Are builders missing this item on drawing 3 or are they simply electing
to notch the rear spar later when they build the fuselage and do it to fit. It seems to me that access would be more difficult once the rear spar has its reinforcement bars installed.
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Clearance for elevator horns - RE: - View Thread
I waited to trim mine until after I mounted the elevators. It would have been a cleaner cut had I made it earlier, but I didn't know how big it should be at the time. Van's plans didn't have a dimension for the cut on my kit (#379), but if they call it out now -- by all means use it. If they don't provide a
dimension, don't hesitate to "go big" there. It's just a flange, and it's not even visible, really. Easier to cut it and debur it before the HS skin gets riveted on.
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Clearance for elevator horns - RE: - View Thread
As I reacll, the earliest sets of RV-7(A) drawings did not have the cut out notch shown. My early RV-7 was one of them. And I beleive it came out later as a revision in one of the 'RVators'. I notched it then after the HS was complete. Not as easy as if I could have trimmed it before the HS spars were riveted on. Can't recall if it was really necessary to get the full range of elevator movement, but Van said put it there, so I did.
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Countersinking spars - View Thread
I just started my HS and began dimpling. I did not countersink my spars, I dimpled them with the same dimple dies I am dimpling the skins with. Is this a problem? Did I miss something obvious, I don't know if it says anything in the manual as I left it at the hanger.
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Countersinking spars - RE: - View Thread
I was not being precise when I stated the 0.040 thickness. It truly is simply geometry dependent. The Idea, as previously stated, is to not create a knife edge in the hole by countersinking all the way through to the other side. A little trig on an AN426AD3 rivet shows the head to be ~0.0323in. deep. If you countersink for a flush head, it looks like .032 material will be at knife edge. One would think that a .010in straight wall would be a reasonable remainder after countersinking, which pushes the minimum thickness to 0.040 plus. If you want to reduce the remaining straight wall below 0.010in, you can approach your sheet thickness of 0.032in but will likely enlarge the hole if pushed too far. It all depends on what you are comfortable with. An AN426AD4 rivet has a head thickness about 0.0377 inches. I haven't worked out the head thickness for other rivet geometries. My actual point was not this at all but simply that one is not REQUIRED to machine countersink when sheet thicknesses exceed .040in. Form countersinking (dimpling) can be done on thicker materials as long as you have adequate dies and squeeze machinery.
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Countersinking spars - RE: - View Thread
Actually, I believe the rule is that you may (not must) countersink anything OVER 0.040in thick. That number is really rivet diameter dependent. You really don't want to countersink anything thin enough to leave a knife edge in the finished hole. You may DIMPLE any thickness your equipment has the grunt to do. If your dies are substantial enough and you have a healthy press available you could dimple quarter inch stuff. You just need to be wary that dimpling the spar flanges may stretch or even shrink the edge if the dies are not closed completely. If the rivet line remains straight after the dimpling, pat yourself on the back and move on.
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Dimpling the forward most middle rivet holes in the HS skin - View Thread
Quick question: What's the best way to dimple the forward most holes in the middle of HS skin? I tried it with the c-frame last night with a helper and needless to say, I don't like the results. It was a pain in the ass to open the skin enough to get it to sit flat on the on c-frame. My thoughts are to:
- Place the opening of the c-frame on the very edge of the work bench
- Put the mail dimple set on the c-frame piece that you strike with your hammer of choice
- Flip the skin upside down (so that it opens downward)
- Push the skin into the c-frame and let the work bench do the work of opening up the skin
- Push/hold the male dimple into possition and strike with the hammer.
- Rinse and repeat as neccesary
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| The "cover your butt" section |
This website was built to document my work on my RV-9A in
compliance with the FAA requirements needed to certify my aircraft. My experiences and comments are by
no means to be considered as instructions on how to build an RV-9A or any other aircraft.
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