Thursday, August 18, 2011

Some thought required

It seems like I've been doing a lot more thinking lately. Deep thought is pretty much the norm at the paying job, but I like to spend my off-work hours avoiding cerebral activity as much as possible. This week, though, I've been faced with a virtual cordilleran of mental hurdles.

First came a new internet game that I've been playing. It's called Words with Friends, but it's really an almost direct rip-off of Scrabble. The big differences are that it's far more asynchronous and the other player can be anywhere on the planet. Given that my opponent and I both have other responsibilities, it is often the case that our moves are separated by hours.

It's really quite fun, but I'm getting pretty frustrated. I spend 15 or 20 minutes trying to come up with pithy, insightful words but usually end up with things like 'huff', 'tern', 'geek', 'hog', and 'opine'. Some of those are pretty clever, but mostly I end up sound like a first grade reading primer. My opponent, on the other hand, was clearly a Scrabble prodigy; he plays for the most ruthless score he can manage. 'Opine', a word I was inordinately proud of, scored nine points. My opponent plops down "lat" (that's a word???) but has it sitting right next to the 'ote' of one of my words, 'quote'. This apparently also spells such useful words as 'lo' and 'at' and scores an astonishing 68 points.

I'm clearly going to have to up my game.

Anxious to get away from the ignominious defeat that I will inevitably suffer in the word game, I decided to give Pete a call and see if he wanted to do some more work on the canopy frame. It seemed easy enough, although we would be working in a new medium: cardboard.

All we had to do was cut out some cardboard to put a 1/8" gap between the canopy frame and the fuselage sides. Easy enough.

It turned out pretty well, even though I was using some freebie scissors that I got at Harbor Freight, the Home of Plastic-Based Scissors and Low-Lumen Flashlights.

It all went downhill when the next step directed us to ensure a 7/16" gap between the frame hoop and the instrument panel. The trouble arose when we found that the hoop wasn't consistently straight. It seems to have a bend in it at the center weld that causes the outer parts of the hoop to be further away from the panel than the center part. Try as we might, we couldn't come up with a way to bend the hoop straight.

Having thought about it for awhile, I now think we can do it by removing the frame and placing the center weld area on the top cradle of an extended jack stand. That will provide support at the center of the hoop while we press on the other portions.

It means undoing this fancy clamping work that we did, though.

When I got home from the paying job today, I had an email from a guy asking about the RV-6. I normally wouldn't share it here, but it was easily the most interesting and thought-provoking inquiry that I've received:
Dave, good afternoon.

I'm constantly browsing through barnstormers and for a RV-6 that catches my eye. I keep coming back to yours yet it lacks the 360 C/S that I've been holding out for. I'm hoping to use it for local gentleman's aerobatics and some x-country legs on occasion. I don't need the most efficient cruising bird out there so I've been leaning towards acceleration performance.

I love the old warbird look you have going on and the instrument configuration. My only hold back seems to be what's up front. What has been you experience with it compared to some other RV's you've been in? I know the benefits of the FP prop are simplicity and cost but what am I realistically giving up performance wise?

Also, do you have any adjustments to the oil system for inverted flight or vertical maneuvers? I've read where some lean the oil resevior 15 degrees back so it has constant flow while going vertical. I'm not looking for a G monster airplane, but just something I know I can safely have fun in with two people on board. I look forward to hearing back.

I found this interesting because I myself have wrestled with questions like these. Should I add IFR capability? Should I get a bigger engine? Is it really worth the cost? I spent some time on my reply:
I'm going to have to set aside the fact that I'm trying to sell an airplane
put on my consultant's hat for a few minutes.

I've always said that when it comes to airplanes, you need at least two but
no more than five to do everything that you want to do. Since few of us can
afford a Harrison Ford lifestyle, we have to make do with one. Everything
about the design of an airplane is a compromise and it is rare to find a
design that does everything that you want, but the RVs come closer than
anything else I know about. Even with the RVs, though, there are compromises
between the different models. In fact, given the level of builder
customization that goes on, there are compromises to be made within each

If you had said that your primary purpose was cross country or day trips, I
would say that any of the RVs would do, but an RV-6 or RV-7 would be
preferred for the side-by-side seating, even when flying alone. And unless
you live in a high altitude area, I would have said that your best choice is
an O-320 with a fixed pitch prop. At higher elevations you would want the
better takeoff efficiency of the constant speed prop, so the trade off in
increased weight and complexity would be worth it. At really high altitudes
you would want the even better climb performance of the O-360. But down
below 4,000' or so, I'd say stick with the lower weight and lower fuel burn
of the O-320 and a fixed prop.

When you start talking about aerobatics (or formation flight, for that
matter) as taking primacy over travel, I would recommend an RV-4 or RV-8.
When it comes to aerobatics or formation work, it is much better to be
sitting on the centerline. With the RV-4, you'd be fine with the O-320, but
for an RV-8 I'd look for an O-360. Depending on the type of aerobatics you
want to do, the constant speed prop is optional. I just pull back the
throttle at the top of the loop to keep from overspeeding the engine. Since
everything I do ends up at the same altitude and energy level as when I
started, I don't need the extra climb performance from the bigger engine.

For formation flying the CS prop it's pretty much mandatory because of the
more rapid acceleration and decelleration it provides.

This is not to say that you can't to aerobatics in an RV-6 or RV-7. You can,
and I do. Without inverted oil, I limit myself to positive G maneuvers only.
I don't figure I'm giving anything up - I've tried negative Gs and I don't
like them. At all. So if by "gentleman's aerobatics" you're talking about
some loops and rolls now and then, just about any RV will do. If you're
talking about being able to fly inverted for even a few seconds, you need an
external oil tank and plumbing for inverted flight. Just be aware that the
queasiness factor is increased a lot by sitting off center.

Now, back to my airplane. I have never missed the cost, complexity, and
weight of either the O-360 or the constant speed prop. I have on occasion
missed the performance aspects of them, though. I tried my hand at formation
flying and fortunately didn't develop a taste for it since it is really much
harder with the FP prop. I've also had hot summer days when I would have
appreciated the extra 30 hp from an O-360 just for getting off the runway,
or when trying to climb above 10,000'. That 30 hp doesn't buy you much in
cruise speed, but it sure helps in climb performance. That said, when flying
at gross weight on a hot day I still get around 500-600fpm at sea level.
Light on fuel and with just me in it, I often see 1,500 fpm. The RV is such
that there is a definite performance difference as weight and weather
change. I think the gross weight takeoff and climb performance is probably
where you would see the most gain from the bigger engine and more efficient
prop. Hard to say if it's worth the cost, though. It wasn't to me when I was
asking myself these very same questions, but then again I'm building an LSA
so I'm obviously more focused on lower costs and simplicity.

Regarding vertical flight, my vertical flight has been limited to climbing
into a loop, but I know guys that don't have inverted fuel/oil systems that
regularly do hammerhead stalls. I've personally never had the guts to try

I can provide you with a couple of resources if you're still interested.

There six years worth of the kind of flying you get from a O-320 RV-6 here:

There's a lot of "no holds barred" maintenance history in there too.

For more specific details, I set up a small FAQ page:

Whatever you decide on, I wish you luck and hope you end up with an RV. I
can honestly say that buying an RV was the best flying decision that I ever
I'm worn out. I need to rest up a bit before I get a response to my last move on the word game - there are only seven letters to play at a time so I don't think I'm going to be able to use 'cordilleran'.

More's the pity. It would probably be worth 12 points or so.

No comments:

Post a Comment