Lightening Holes in rear VS Spar?

Hello fellow -9 builders. I had a quick question: on the vertical stabilizer, there are lightening holes in the rear spar which are 'optional'. I spoke with Steve (alpinelakespilot) earlier, and he didn't cut them. We both agreed the weight saving would be a mere ounces. I'm just curious: what did the rest of you do?

Thanks!

every 10th of an oz counts..

I didn't cut mine either.. but some people cut every thing they can.. keep
in mind though the 9's tail is suppose to be heavy compared to the others..
so It might be a better idea to lighten everything.. I didn't for what its worth..

I have lots of questions also .. but some of them get tired of ansering the same questions over and over.. keep asking though.. every now and then I ask the right questions and they get answered very well , others no one acts like they see those.. have fun and enjoy the process..


Danny..

I cut mine...It gave me practice using the flycutter. The whole process took about an hour and realy looked nice when it was done. You need to use lubrication and go slow especially when you get to the end of the cut. But as for weight...it wasnt nore than a few ounces so use your own judgement.

good luck

Jim Kinsey
7A wings

I didn't cut mine...seemed like a lot of work with room for mistakes for only a few ounces. I will bring one less soda along for the flight to make up for it.

"Build lightness in"

"Build lightness in" is what Van's told me when I called and asked about the holes so I cut them. There are a lot of places Van's tells you to trim/cut/drill etc for weight savings. I've done them all and am not sure they are worth the effort but then again, I plan on using a little O-290 so any weight savings will be worth the effort.

I cut mine but probably wouldn't if I build another -9.

Ready to rivet flap TEs,
Steve

Aft weight needed with C/S prop...

I kept the weight in the tail to offset some of the extra weight up front from the Hartzell constant speed prop and the 160 HP ECI/Penn Yan Aero O-320-D1A.

Jerry K. Thorne
RV-9A N2PZ

cs prop (envy)

wishing I could go that route.. not sure I can handle the complications.. though.. can a cs prop be set like a fixed pitch till the pilot learns how to fly and is ready for the transition ? like put the stops at a noral fp pitch till I get the hang of things ? anyone tried this ?


Danny..

N941WR said:

"Build lightness in" is what Van's told me when I called and asked about the holes so I cut them. There are a lot of places Van's tells you to trim/cut/drill etc for weight savings. I've done them all and am not sure they are worth the effort but then again, I plan on using a little O-290 so any weight savings will be worth the effort.

Click to expand...

I got the same reply back in the day from them. So I cut every hole, lightened everything that the plans said to... Years later I was at my very first flyin. As I walked up to my plane, Van was standing in front of it reading my prop card. "This your plane?" YES "Congratulations on keeping it nice and light" mine came in at 1034. He says, I always tell the shop guys to keep them light as they fly better that way, but everyone wants so many extras these days. and so ends my first and only coversation to date with Van himself.

akarmy said:

I got the same reply back in the day from them. So I cut every hole, lightened everything that the plans said to... Years later I was at my very first flyin. As I walked up to my plane, Van was standing in front of it reading my prop card. "This your plane?" YES "Congratulations on keeping it nice and light" mine came in at 1034. He says, I always tell the shop guys to keep them light as they fly better that way, but everyone wants so many extras these days. and so ends my first and only coversation to date with Van himself.

Click to expand...

Andy,

That's good to hear. My goal is 1040 lbs and I think I might (should?!) come in well under that with the O-290 and Dynon EFIS and EMS (Only steam gauge will be an altimeter, airspeed, and wet compass for backup.) and just paint for an interior. I have primed everything and I wonder how much that adds? 10 lbs maybe? Oh, and the -9 tip-up is supposed to be lighter than a -9A tip-up so that should help some more.

I figure I have to keep it light just to keep up with guys like you who have "big" engines.

C/S vs. fixed-pitch prop

Danny,

I would not worry about trying to use the C/S prop in "fixed-pitch" mode. I have had only one flight in an RV-9A with the C/S prop and it was very enlightening. You can leave the blue knob all the way in, and that is the way it is done on take off to get maximum RPM and not to overheat the engine. When you level off at altitude and trim the prop for cruise, the manifold pressure and RPM are used to set the prop pitch. The result is higher cruising speed and changes to the cylinder heat temperatures (CHT) and exhaust gas temperatures (EGT). When the mixture is leaned properly, all those parameters must be in the safe operating zone to maximize the life of the engine.

When it is time to land, pulling the throttle back will reduce engine oil pressure, and with that, the prop will reduce pitch even if you don't push the blue knob in to change the valve setting on the prop governor. The effect on airspeed is like putting on the brakes. That is why it is easier to get into short fields with a C/S prop. You get lower airspeeds with a given engine idle RPM with the C/S prop compared to a fixed-pitch "cruise" prop.

Jerry K. Thorne
RV-9A N2PZ

Cut all the weight out that you can. Use your flycutter. No oil required. This is aluminum, it's soft and disipates heat fast. I'll admit the flycutter can make a lot of noise when cutting but just press on. I've cut several panels with it and used it building this 9 and I have never used lubrication when cutting aluminum.

Just my 2 cents.

I cut mine. 3.1/8 oz removed. looked good but I don't know if it was worth the time.

Flycutter use

The flycutter will work fine but can be a wee bit dangerous. Use the slowest speed on the drill press, make sure the part is clamped down on some wood or aluminum scrap, and don't use much pressure. If you press hard or go too fast you'll harden the aluminum and make it VERY hard to cut. You might want to get some cutting fluid designed for aluminum, as it helps keep the tool and part cool and happy.

Steve Zicree
RV4 Finishing (slowly)

Out of interest. Does anyone know the total weight saved if you make all the optional weight savings as per the plans?