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05-02-2007, 05:11 AM
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Join Date: Jan 2005
Location: Lake St. Louis, MO.
Posts: 2,346
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Quote:
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Originally Posted by RVF-84
This may be old news but just in case...
The good 'ol days of cutting lightening holes in the vertical stab spar doubler seem to be over. My RV-8 emp kit came, (04/07) with the lightening holes already cut out.
(The plans still show the measurements and they're still listed as optional.)
You can almost hear the sound as thousands of fly cutters cry out as one....
Peter
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Pete....Here is a thread I started to document exactly how much weight was saved by cutting in the optional lightening holes in that doubler. My particular weight savings was slightly increased over the plans callout because I very slightly increased the diameter of two of the middle holes in the pattern. BTW, I used the tried and true fly cutter.
http://www.vansairforce.com/communit...ead.php?t=2445
__________________
Rick Galati
RV6A N307R"Darla!"
RV-8 N308R "LuLu"
EAA Technical Counselor
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05-02-2007, 05:52 AM
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Join Date: Feb 2005
Location: Pennsylvania
Posts: 89
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I used the Rotabroach cutter and it worked just fine. Dean
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05-02-2007, 06:03 AM
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Join Date: Mar 2005
Location: Northern California, USA
Posts: 537
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Quote:
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Originally Posted by Mhead
For those of you that have taken the time to cut the lightening holes, what is the weight saved for your model RV and would you do it again based on the time, effort, and slight chance of an emergency room visit?
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It's maybe 0.1 lbs. If it weren't all the way at the back end of the airplane, I might not have bothered. So far, though, I think I cut every optional lightening hole I've encountered...and then more than made up for it by adding all sorts of not-in-the-kit stuff!
I clamped the heck out of the part, and was reasonably confident I'd emerge unscathed.
__________________
Martin Gomez
Redwood City, CA
"My RV-7 is a composite airplane: it's made of aluminum, blood, sweat, and money"
RV-7 Slider QB
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05-02-2007, 08:45 PM
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Join Date: Jan 2007
Location: Sacramento, CA
Posts: 146
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Thanks muchly!
I appreciate the excellent suggestions and comments.
I just ordered a fly cutter from ATS, so I'm going with the cheapest solution first.
Duly noted are cautions re safety. I've got a full face shield, gloves, body armor (not really), a first aid kit, and maybe I'll put 911 in my speed dialer.
As a sidebar, I have little option other than to cut every possible lightening hole. I have some serious "mass" issues ahead. I've been priming everything (no such thing as a "light" coat with the rattle cans I've been using), I plan a CS prop, and I have this odd passion for servos, switches, and every conceivable avionics gadget.
Regards all - - Tom from Sacramento
__________________
Tom in Sacramento.
RV-7A, Emp Kit finished (only 2 yrs!).
Wing construction officially started.
N7877A Reserved. Planning to call it "The STREAKER"
VAF # 1635
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05-05-2007, 04:01 AM
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Join Date: Mar 2005
Posts: 5,685
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Fly Cutter, hole punches and hole saws
I used them all in the order shown above. I thought the hole saws from the local hardware store were the best. One caution - don't even think that after the hole is cut out that you can go back in there with the hole saw and clean up the edges. Once you loose the centering function provided by small center locating drill it will eat surface material outside the hole. This can be especially disturbing when you are cutting a hole for a new instrument in your completed airplane. The MRB may disposition use as is but the pain remains.
Bob Axsom
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05-06-2007, 05:33 PM
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Join Date: Mar 2007
Location: Upper ny
Posts: 78
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hand flycutter
I have no idea why Vans instructions dis hand drill fly cutters. Mine work perfectly. The only difficulty is finding hand drills. They turn up in garage sales.
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05-10-2007, 03:03 PM
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Join Date: Nov 2005
Location: AUSTRALIA
Posts: 749
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Quote:
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Originally Posted by Mhead
For those of you that have taken the time to cut the lightening holes, what is the weight saved for your model RV and would you do it again based on the time, effort, and slight chance of an emergency room visit?
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I did not cut the VS lightening holes. I recently weighed my 9A which is equipped with an 0-320 and Hartzell CS. The c of g calculations work out pretty good. However, I am a relatively light pilot at 76 kg and if anything, I would actually prefer a little extra weight in the tail.
Fin 9A
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05-28-2007, 09:07 PM
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Join Date: Mar 2005
Location: St. George
Posts: 973
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RE:Flycutter Worked for me
Quote:
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Originally Posted by Captain Sacto
Question for the experts...
The rear spar for the vertical stab on the 7A has an eighth inch thick doubler that, according to the drawings, permits optional lightening holes. Two of the holes are 2" dia, and 5 are 1.5" dia.
It appears as though I have two options if I want to cut these lightening holes. I can buy the Rotabroach cutters from the good folks at Avery for $ 175; or, I can get an adjustable circle (fly) cutter from STS for $13.95.
My question is... do the Rotabroach cutters perform in a sufficiently superior manner to justify the >10X cost?
Any and all comments and suggestions welcome.
Thanks in advance! - - Tom from Sacramento
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Made that first 3 1/8 hole in the panel today for the Trio EZ Pilot instal. I had used the flycutter in the past with some success.....but...Dan C. got me thinking.......The punch $$$$$$$$$$$$$$ tools do look great for the job. But having droped mucho grande denaro on stuff this past week I decided i would give the fly a try.
1. Measured the spot to have the hole about a zellion times. 2. Drilled an 1/8 starter hole and increased it to 1/4". 3. Installed the flycutter in my drill press. Put the panel on a wood panel sized to the instrument panel. 4. Clamped the wood/panel to the drill press base and adjusted until the fly center bit lined up perfectly with the 1/4 inch hole in the panel. 5. Set the diameter of the flycutter to cut the 3 1/8" hole and rechecked it about a zellion time. 6. Before turning the press on I lowered the flycutter to the panel and slowly turned the drill chuck with my hand a number of revolution to both begin the cut and to check for accuracy. 7. Double checked to make sure all of the set screws on the fly cutter were tight and that the drill press base was tight. "YES TO BOTH" 8. Turned on the drill press and slowly lowered the flycutter to the panel and slowly but surely added pressure. 9. Turned off the drill press and had to admire one fine flycut hole.
So my experience is........use the flycutter......save the $$$$$$$$$$
But I also think that new hole saws from Lowes Aero or Home Depot Aero would also work great. I think the key is to use a drill press and make sure the part being drilled is absolutly 100% clamped down!!!!!!!
Frank @SGU RV7A "NDY" PANEL/ELECTRICAL ....engine being built @ America's Aircraft Engines Inc.
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10-24-2007, 09:54 PM
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Join Date: Mar 2005
Posts: 55
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Here's a neat tool to flare your lightening holes. Just add a little lubricant.
A form block with a hole is best for clamping. Pic is an example.
Ron Jennings of EAA 21 came up with this.
Last edited by BobMoe : 10-24-2007 at 10:01 PM.
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10-24-2007, 10:24 PM
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Join Date: Dec 2005
Location: Mahomet, Illinois
Posts: 2,195
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I agree with Bob Axsom. I bought the cheap hole saws from Menards and they worked like a champ. Each diam blade cost me about $3. Aluminum is so soft, the hole saws intended for wood work fine, given the few holes we have to cut. I too won't go within 20' of a fly-cutter.
Terry
__________________
Terry Ruprecht
RV-9A Tip-up; IO-320 D2A
S. James cowl/plenum
(Dues paid thru Nov '18)
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