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praterdj

Well Known Member
In Larry Pardue?s great write up of the LOE fly in he talked about having an opportunity to judge.

During that discussion he mentioned that completely filled wings will be marked down.

What are completely filled wings? :confused:

I know this is probably a goofy questions but I?m just curious as to what he is referring to.

I want to be at LOE next year in my 8! Too much missed fun so now I have a deadline to shoot for.


Pratdj
RV-8 Empennage
 
filled rivets

I believe he is referring to filling the rivet heads with some sort of filler - trying to give it a composite airplane look. Generally judges want metal airplanes to look like metal airplanes and plastic airplanes to look plastic.
 
taboo

hiding rivet heads filled with filler, i.e. invisible rivets/smooth surface.....considered heresy by most aluminum builders ("if you want composite look, build a composite airplane")
 
Right, but it might make it marginally faster. I know a couple of guys that have done this to Cessna Cardinals before repaint and picked up a couple knots. Then again, that might just be from the new paint. It certainly adds weight. I had someone suggesting squeegying primer over the heads. Said it doesn't hide, but makes it so you don't get those little white rings when you wax it. Smooths it out without making it hard to find rivets :).
 
This Judging Thing is a Total Waste

There is no sense to this activity at all. You see from the report even the judges joke about it. If you want to do something special to your airplane don't let possible third party prejudices stand in your way.

Bob Axsom
 
Was this done to Mooney wings? It's been years since I flew one but I remember the wing being pretty smooth.
 
Thanks for the input. I kind of like the look that the rivets give an RV. I might squeege primer on it though. Makes sense you might pick up a knot or two.

I'm not worried about judging but I don't see anything wrong with a person wanting to compete. I just want to make mine as nice as I can without going overboard. I'll probably use the 5 or 10 foot rule. Heck, by the time I get that far I might use the 10 foot at 170 knot rule! ;)
 
I'm a software guy, and not an aeronautical engineer, but I find it hard to believe that filling-in the rivets would increase the speed of an airplane. That is, unless the rivet indentations were so large that the metal around the rivet was mushroomed up into the airstream. In that case, it would probably be a wash, because the weight of the filler that you would have to use to fill the holes would offset any increase in speed due to a smooth surface.

Of course, this is just my opinion.

Tracy.
 
putty

you sand 99.9% off so you add a couple thousandths ring to the rivet. If I said a 1/2 lb. it would be too much.

this guy built a stunning plane and the material Proseal PRC 1422 (?) is used for filling. I'd say all the weight is in the primer.

http://www.pbase.com/image/48596419

a can of putty is 1.25 lbs. and you sand half of it off.

and I always hear the story about dave anders, had a polished plane, melted 3 canopies, painted and he swears the plane is faster. thought it would be slower because of the weight.

FWIW
 
thallock said:
... I find it hard to believe that filling-in the rivets would increase the speed of an airplane. That is, unless the rivet indentations were so large that the metal around the rivet was mushroomed up into the airstream...
Click to expand...

I'm glad this issue came up because having a little (very little!) background in fluid flow caused me to entertain the idea of filling in the rivets on my -10 (that I will be starting in Jan :) ) From what I've seen, there isn't much of a ring around the rivet heads, but we're talking about boundary layer flow here, which is where most of the drag originates from. So whatever you can do to clean up the boundary layer flow should provide some sort of gains. The question is just how much. If its 5 knots or more to do the whole airplane, I figure its worth considering. Any aero guys care to weigh in??

Mark.
 
hot rivets

btw-- the plane I linked to also did annealed? hot rivets. he scientifically heated them and had a lab freeze them at a precise temp until he needed them. IIRC.

and of course, time and money was not a consideration. Successful farming operation.
 
Filled rivets

Keep in mind, some guys have used one piece skins. This will reduce the seam lines and give a cleaner look.

A while back I saw a RV6 that wasn't familiar to me land at my airport (P19). I rode my bike down to take a look. The red plane had been in a bad hail storm and all metal surfaces looked like a golf ball. The owner said he replaced the canopy and decided to fly it as is. He reported the performance was no different and he even felt it stalled at a slower speed. So the moral of the story, if the rivets are protruding then they could be an issue, but recessed rivets should cause any reduction of performance.

If it was mine I would have pianted it white and put the Nike logo on it :)

Darwin N. Barrie
P19
 
One myth that keeps popping up in this forum is that weight has a significant impact on speed. It doesn't. It affects rate of climb, stall speed, takeoff distance, landing distance, but not speed.

If you don't believe me look at Van's performance numbers on their Web site...for an RV-7, the difference between the solo and gross weights is 1 mph in top speed. That's for a 400 lbs difference in weight!

(If you want to know why, I can walk you through the physics. In the past, when I've tried to bring engineering into these discussions, somebody often replies with an idiotic comment like "Why don't you guys spend more time building and less time arguing about minutae"...as if they owned my spare time.)

To me, filling the rivets on a clean airplane like the RV is a clear case of polevaulting over a mouse turd. If you're doing it to make it faster, there are probably better ways to do it in a knots/man-hour sense.
 
RV7Guy said:
A while back I saw a RV6 that wasn't familiar to me land at my airport (P19). I rode my bike down to take a look. The red plane had been in a bad hail storm and all metal surfaces looked like a golf ball. The owner said he replaced the canopy and decided to fly it as is. He reported the performance was no different and he even felt it stalled at a slower speed.
Click to expand...

I learned to fly RVs in a red 6 that had hail damage all over it just like you describe. I think it is somewhere out in California now. Anyway, it flew great and was a blast to fly. I should try and remember that plane whenever I come to one of those "ehh" spots in the project where I have a choice between "let's spend another week making it absolutely perfect" and "let's keep moving"...!

mcb
RV-7 emp done, waiting on QB fuse/wings
http://www.rv7blog.com
 
I think the hail damaged one you refer to might be the one at Fox Field here in Lancaster, CA (WJF). Several difference people have told me that it flys just like any other RV with no noticable performance differences. But that's all second and third hand info.
 
Good Point

mgomez said:
To me, filling the rivets on a clean airplane like the RV is a clear case of polevaulting over a mouse turd.
Click to expand...

Very eloquently put! :D :D

Man, I need to get this semester overwith so I can get my mind working on building instead of day dreaming!

Mark.
 
I've only seen one RV that had all the rivets filled and there was a whole lot more than a couple of thousandths of filler there. No matter how you go about it, there is a depression around the rivet, and to get that plasti-plane look you have to fill all of it. Certainly more on some that on others, but overall quite a bit of filler. The plane I saw looked spectacular until I got up real close and found what I had suspected from the start. Lots of little teeny cracks around rivet locations and a few spots where the filler was about to pop completely off of the rivet. I've seen similar stuff around empennage tips that have been blended into the aluminum. My impression was that filler and aluminum aircraft don't mix all that well and I plan on using a minimum of the stuff. I think the different expansion rates and the temperature extremes are just too much to overcome.

Steve Zicree
RV4 with lots of wires but no motor
 
Hey Bob-- I'm going to hang a "Do Not Judge Me" sign on mine. :D

rudderdone4ni.jpg


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canopydone6bq.jpg
 
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It felt like early X-Mas unwrapping the canopy after having it sit around for three years. and the rudder--- I can't believe it. I couldn't get it to fill/hide. the above pict-- went to work on it a second round and I found loose rivets. Best I can figure is I didn't enough Proseal in there. So, I fixed it but it's only a matter of time as to when at least one rivet will show itself.

I'm going to start working on my sign. :(

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