[andrew phillips]

Hi All, On the Diamond Eclipse I trained on they had plexiglass inspection covers for the aileron bellcrank and flap mechanism. You could see all the nuts and bolt (with torque seal) at every walk around. I thought it was a great idea. Has anyone done this on an RV...if so, have any pics?

Andrew Phillips
7A QB

 

[Kyle Boatright]

This has been suggested before. The response from Van's (possibly catalogued in the Matronics archive) was that the metal covers are part of the load bearing structure so don't deviate from the plans.

 

[osxuser]

Hear hear!, Part of the reason I didn't like the idea of going to fiberglass panels on the fwd deck, when those panels are cut for panel access in -7's or -9's. Stick with Aluminum.

 

[Paul Eastham]

Another reason not to do it: the cover plates bend a bit when screwed in, which can break the epoxy if that's what you used to attach the plexiglass.

 

[alpinelakespilot2000]

Hi All, On the Diamond Eclipse I trained on they had plexiglass inspection covers for the aileron bellcrank and flap mechanism. You could see all the nuts and bolt (with torque seal) at every walk around. I thought it was a great idea. Has anyone done this on an RV...if so, have any pics?

Andrew Phillips
7A QB

Can't comment on whether or not inspection panel covers are generally "load bearing" or not, as others have questioned above, but "23 Years of the RVator" (or whatever the most recent edition is) has a article about making plexiglass windows for the aft. fuse inspection panels. (Just read it last night--I think if the "fuselage" section of the book.) I highly doubt Van's would publish something in their "best of the RVator" collections if they didn't generally approve of the concept. It might be worth a specific call to Van's though.

If you get an answer I'm sure we'd all appreciate hearing what it is, because many of us would agree with you that being able to view them on preflight is a very good idea. Good luck.

 

[Low Pass]

Can't comment on whether or not inspection panel covers are generally "load bearing" or not, as others have questioned above, but "23 Years of the RVator" (or whatever the most recent edition is) has a article about making plexiglass windows for the aft. fuse inspection panels. (Just read it last night--I think if the "fuselage" section of the book.) I highly doubt Van's would publish something in their "best of the RVator" collections if they didn't generally approve of the concept. It might be worth a specific call to Van's though.

If you get an answer I'm sure we'd all appreciate hearing what it is, because many of us would agree with you that being able to view them on preflight is a very good idea. Good luck.

5-6 yrs ago I spoke personally with Van's personnel (name Scott rings a bell) and he said the wing plates carried a structural load. What I took from this was that the loading of the panels should be considered. If one could design a sufficiently strong plate with a clear insert, go for it. I personally dumped my handy-dandy aileron & elevator inspection covers that had Lexan inserts for stock design solid aluminum.

 

[gvgoff99]

??

I was wondering if I would actually take a GOOD look under there if I had the ability to do so. I also wonder how many aileron bell crank or rear boom failures have happened in the RV's and if some have happened would they have been picked up by a quick look through a piece of plexiglass? If the covers are structural it is a no brainer answer and if they're not then it seems like over kill to me to put in a (thin) piece of plexiglass. Since it is "experimental" one can do what they wish so mine is only an opinion.

 

[dan]

It has been a while, but last time I perused the RV accident history (http://www.rvproject.com/ntsb.html), I don't recall seeing control system failures. Lots of bad landings and bad decisions, but no loose bellcranks that I recall...

 

[GAHco]

Put it together right

Put it together right, use castellated nuts and cotter pins and then inspect it twice before closing it. Torque seal the rod end jam nuts.

If you worry allot use MS17825 Castle nuts that also are a nylon insert locknut too. This or similar function nuts are used on all Helicopter controls and most turbine aircraft primary control systems.

Always do a Push Pull Rod, Rock and Roll Check on your pre flights.
Are the jam nuts tight? and does your Push Pull rod rotate freely and the same amount in both directions?

Do your ailerons sit in the same position that they are supposed to?

Are your travels symetrical?

If you are still concerned open that plate up and check it out, and make it right.

If after all this you want to see the hardware in its functioning enviroment without pulling the plates every time, dont use plexiglass it is structuraly close to nothing unless bonded in place. Lexan is much better, but unless tested against the aluminum plate, I couldnt say its good enough.

Somebody with much more time than I have will be the one to report on the final results. It would be interesting

 

[mark manda]

Yes-- if you're still interested about this next week, I'll post some picts.

I can't post from my weekend web browser.

 

[GAHco]

Yes

Yes-- if you're still interested about this next week, I'll post some picts.

I can't post from my weekend web browser.

Cool, I will be gone next week anyway, I am presenting a couple classes at an IA renewal in Ohio.

 

[Davepar]

Not that I'd recommend it, but all the nuts can fall off the bellcrank bolts and it'll still work. All the bolts should be installed from the top and thus won't fall out (for positive G). Very good design.

 

[alpinelakespilot2000]

From p. 98 of 24 Years of the RVator:

"See-through Inspection Covers [1998, 2nd]
Most speciality aerobatic planes use transparent inspection covers, making the belcranks and important control linkages easy to see on every preflight. they are usually made of 1/8 or thicker Lexan or Plexiglass. I played with this, but couldn't find any material thin enough to match RV skins, so I used traditional covers. Kevin Lane thought this through a little further and came up with a solution. He simply cut a 2-3" disc out of the center of the aluminum cover and bonded in a piece of Plexi, thereby combining the best of both worlds." [Picture included]

I have no plans at this time to do this modification, but it doesn't seem like a bad idea. True, it may not happen all that often (perhaps it never has on an RV), but the consequences of it happening can be serious. I would point to both the Sean Tucker incident last summer where he had to bail out because his elevator linkage failed, as well as Paul Dye's great write up a few months ago about how he found that one of the bolts in his control column almost came out. Perhaps an inspection window or access wouldn't have helped in these specific instances (I'm not sure what the exact failure was in the first case), but having a window to visually see the security of the bolt/nut combination would, if reasonably preflighted, minimize these potential occurences.

One other point: this RVator article is talking about the aft-fuse inspection panels. Perhaps Van's does endorse them here but migt not on the wing panels. Might be worth checking into.

Just more food for thought.

 

[mark manda]

haven't tested in flight

Left wing underside.

Can you see anything?

 

[dan]

Guys, I would be a heck of a lot more concerned about the plexi de-lam'ing and then possibly jamming up the controls. I personally think risk is being ADDED. Just my 2 cents.

 

[N8RV]

... AND are you really going to crawl under your wings with a flashlight during every preflight?

 

[N520TX]

Lexan

I used Lexan for the inspection panels that cover the bellcrank in the wings, and under the h'stab (one side only) and, yes, I do bend over (with flashlight if needed) and inspect the bellcrank bolts on every pre-flight.

Flying 3 yrs now, with no problems or hint thereof.

Like Andrew, I learned on a DA-20 - and the got the idea for the clear panels from that aircraft.

 

[cytoxin]

the bigger picture

Guys, I would be a heck of a lot more concerned about the plexi de-lam'ing and then possibly jamming up the controls. I personally think risk is being ADDED. Just my 2 cents.

definately would be my concern. are you gonna remove the floor pans at the control column as well. this IMHO is just adding risk to a very reliable design.
if you are concerned about disconnect possibilities do as a previous poster said and use the heli hardware. self locking nut with cotter pin as secondary safety and the bolt in from the top/direction of flight/or in the direction of rotation.
why put FOD near the bellcrank?
my.02