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Speed,Combat,Scale,Racing => Combat => Topic started by: Al Ferraro on August 16, 2020, 08:29:23 PM
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The Slasher will be terrorizing the vintage combat circles. Here is a new build of my design from 1967 that Jim Vigani scratch built for me using my original model for a template. Now it’s up to me to cover it with silk & dope. I will have a high nitro burning Fox 36XBB up front for power and will be looking to crack that 130mph barrier. I use a plastic bowling pin as a fuel compartment to hold the baby pacifier to feed the monster.
Al
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What Rules?
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Looks like a 15 size ship, 280 sq. in.?
We might need some new wing area/thickness rules or this event is going to become meaningless pretty quick.
Motorman 8)
Dimension wise, the wing is an exact duplicate of the original 1967 version, airfoil and all. 300 in2 wing area.
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Actually we used to think that was a good idea back in the day.
The rules for slow combat, profile carrier, and some racing events said: 300 squares MINIMUM in the mistaken idea that 300 squares would slow you down. So guys got the idea that going under 300, when you could, would make you go faster.
Later on, the designs of Howard Rush and Richard Wilkins taught us that you could go way over 400 squares and still go fast.
I assembled and flew a Riley Wooten Demon kit in 1973. New guys who saw it said the same thing as somebody in this posting: "What's that? A 1/2A or an FAI?"
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Looking good Al!!!
Walt,
If you flew a 2x4 with engine bolted on the front for combat, its legal! As TS said, what rules!!
Tom
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Well since he annouced it would be "Terrorizing the vintage combat circle (LOL) I'm Guessing Walt was referring to the somewhat loosely agreed upon rules for competition as flown in most contests with an actual turnout and actual combat matches. Maybe Tom was just referring to the East coast "Speed" event for combat models with no rules?
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Looks cool Al.
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For the pure speed event, only models that are known to have been actually used for combat back in the day have been entered so far. All the participants have really complied with the spirit of the event, even down to the engines used. For the stunt speed, anything goes.
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Vintage combat should be something people recognize from back in the day, spirit and intent right? It should be a Voodoo, Sneaker, Vampire, Guillotine, Winder or something like that right?
Motorman 8)
[/quote]
You should check your approved plane list because you have one on there that has a smaller wing area than my Slasher.
PS: Fox Feathers 280 sq inch, Super Satan 300 sq inch (same size). If you ever attended the UMAC Memorial Day contest in Union NJ from 1967 - 1970, and entered fast combat as a junior, there is a good chance you’ve been SLASHED by The Slasher! I consistently placed 2nd or 3rd during those years. I still have the original model and there is a live Stunt Hanger forum member that witnessed me flying The Slasher back when I was 14 or 15 years old. A big part of the fun of the Vintage Combat Festival is to fly and ring out combat models that you’ve flown or seen in years past.
Al
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The silk is on. I’m going to revive my old Slasher icon. I can’t wait to get it in the air. ;D ;D
Al
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Ready to Rumble!!!
Al
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>:D!
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I had the pleasure to fly this plane about a month ago. As soon as Al let it go it felt perfect. Its a great point and shoot plane with a good turn rate. It was a dream to fly and very predictable. I had Al a bit nervous but it felt so right! Good design Al!
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Tom, a bit nervous is a understatement! You were cranking on the Slasher so hard that I thought the pushrod came off, it was only supposed to be a trim flight check to see if I got the warp out of the wing. Next thing I see hard inside and outside loops plus overhead eights, clime and dives with low inverted laps, you really gave it a thorough shake down. Now that the plane is trimmed out I’ll have to try to pick up the extra 6 mph I need to crack 130 mph.
Im glad you liked it, thanks for the review. H^^
Al
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Tom, a bit nervous is a understatement! You were cranking on the Slasher so hard that I thought the pushrod came off, it was only supposed to be a trim flight check to see if I got the warp out of the wing. Next thing I see hard inside and outside loops plus overhead eights, clime and dives with low inverted laps, you really gave it a thorough shake down. Now that the plane is trimmed out I’ll have to try to pick up the extra 6 mph I need to crack 130 mph.
Im glad you liked it, thanks for the review. H^^
Al
It should be easy for your Al, just another 10-15% horsepower!
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Ready to Rumble!!!
Al
Looking good, Al.
The F-Umacer's , as L.S. hisself would say, knew how to have fun.
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The bowling pin is great adaptation! Is the leading edge solid or built-up?
Dennis
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LE is built up with four pieces. 1/1/6" rear spar, 3/16" top, bottom, and LE. Sanded to shape with a box shaper.
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Here’s a video from 9-19-2021 at our Vintage Combat Festival of the my Slasher being flown by Roy Glenn cruising over 124 MPH, turning and burning! My Fox 36x BB was really singing on the 65% Nitro fuel mix. It took a bit to get the needles setting with all the after run oil in the engine, once the engine warmed up you can here the Nitro crackle. I have to say this was a fun build.
Al
https://youtu.be/_v4n471HVfU
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Ready to Rumble!!!
Al
Al Congrats on the new Slasher. It looks great and probably one of the best named combat planes too!
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I want to thank Gary Sinclair for including The Slasher in the Stunt Hanger 2022 calendar. Coincidentally the picture is for September which is the month we have our vintage Combat festival. Gary also did some photo editing and chose the background color! What a awesome job!
Thanks Al
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Timed at a touch under 15 seconds for seven laps. D>K
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[quote author=Blank
Vintage combat should be something people recognize from back in the day, spirit and intent right? It should be a Voodoo, Sneaker, Vampire, Guillotine, Winder or something like that right?
Motorman 8)
Attention conforming Police
I found a old photo from 1968 with the Slasher and my other models hanging on the wall in the basement of my parents house in Union NJ na#
Al
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Al, what kind of silk did you use on the Slasher and what kind of paint?
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I loved the sound the model made in hard turns at high speed. That is something a stunt flyer never hears
EddyR
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Al, what kind of silk did you use on the Slasher and what kind of paint?
I used Thai Silks 026A-902 8MM Habotai pre-dyed Yellow Silk. Randolph clear Butyrate dope brushed on around the edges and let it dry a couple of days. I then sprayed on 3 coats of clear dope over the rest of the panels, waiting a few days and repeated the spraying process 3 more times with light sanding with 600 paper in between. The red is acrylic craft paint. The black is auto paint, and i used a black Sharpe for the fine detail. The graphics are coated with 2part auto clear.
Al
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Hey back in the day people came up with all kinds of combat ships that never got published or kitted. H^^
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I have a question about the combat speed event.
Do you have a set height that the airplane flies at to determine speed?
If the airplane is flown high, the speed is greater and the lap times shorter.
We used to use 4-6 feet to time our combat speed event.
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I have a question about the combat speed event.
Do you have a set height that the airplane flies at to determine speed?
If the airplane is flown high, the speed is greater and the lap times shorter.
We used to use 4-6 feet to time our combat speed event.
We go by any thing under 12 feet, even though i have posted some of my best times trimming the grass. Don't forget these are combat planes and are very twitchy! Getting the best time is to hold the plane rock steady in the groove and that's not a easy task. I can groove a model down at 6ft, better than i could at 18ft getting banged around by the wing.
Al
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We go by any thing under 12 feet, even though i have posted some of my best times trimming the grass. Don't forget these are combat planes and are very twitchy! Getting the best time is to hold the plane rock steady in the groove and that's not a easy task. I can groove a model down at 6ft, better than i could at 18ft getting banged around by the wing.
Al
So using round numbers and some math: at 12 ft your 15 seconds flat (120 MPH) would actually be 15.9 at 6 ' (112 MPH). Assuming you're flying on legal for combat .018" x 60ft lines, That's quite the fudge factor.
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[quote author=Reptoid
So using round numbers and some math: at 12 ft your 15 seconds flat (120 MPH) would actually be 15.9 at 6 ' (112 MPH).
How did you come up with that number? What is the formula you used?
Al
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[quote author=Reptoid
So using round numbers and some math: at 12 ft your 15 seconds flat (120 MPH) would actually be 15.9 at 6 ' (112 MPH).
How did you come up with that number? What is the formula you used?
Al
Not very difficult using math. When you fly higher you decrease the radius/diameter of the circle the airplane is flying. When you are flying at shoulder height with your arm and the airplane at the same height the radius is the length of your lines as measured on the ground. When you fly higher it shortens the radius proportionally according to how high you fly. Extending or retracting your arm can change the radius as well and obviously leading (whipping) can increase speed as well. That's why in an official speed contest you are required to maintain the required height and your hand must be in the pylon for the entire timing duration. The circumference of a 60' radius circle is 377'. The circumference of the circle when you elevate the airplane by 6' (from 6' high to 12"' high) is 353' so when you time 7 laps (1/2 mile at 60' lines) at 6' high, the airplane traveled 2640 '. When you fly at 12' it only has to travel 2471 ' or roughly 6% less distance. That means your speed will be overstated by about 6%. So....15.0 x 106%=15.9=112MPH actual speed.
The speed charts in the AMA rule book are based on the exact radius lines (60'/7 laps=1/2 mile) for that class and assume you are flying at rule book height and with the handle near the center, i.e. on your chest or in the pylon.
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I believe your math is wrong. Consider a triangle formed a 60' line length (hypotenuse), and a 6' height (sine). This is because 12 feet is six feet above what is considered "level" or six feet. The Pythagorean theorem says that the square of the projected flight radius (cosine) is the difference of the square of the hypotenuse minus the square of the sine. Therefore, the apparent flight radius is the square root of [3600 (60 squared) minus 36 (6 squared)], or the square root of 3564. This means the apparent flight radius is 59.7 feet. The speed would then be 59.7/60 as fast as if it were flying a full 60 foot radius. if the timed speed was 120, the actual speed would 119.4 MPH. Even if you said shoulder high is 4 feet, so 12 feet is 8 feet too high, the actual speed would be 118.9 MPH.
I think the 353' circumference "at altitude" is where the error lies.
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Assuming the pilot holds the handle in the middle of his chest (that's how we normally do it), level flight will be at approximately 5 feet. Also, assuming the pilot rotates around the center of the circle, the radius of the circle will be approximately 8 inches longer (center of chest to handle, or about 60.7 feet). At 12 feet above the ground, or 7 feet above 5 foot level flight, the radius the plane would be flying is about 60.3 feet or 0.5% longer. than 60 feet. If anything, the calculated speed is somewhat understated from what would be expected if flying using a pylon - 124.6 vs 124 MPH. (I drew it in my CAD)
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I believe your math is wrong. Consider a triangle formed a 60' line length (hypotenuse), and a 6' height (sine). This is because 12 feet is six feet above what is considered "level" or six feet. The Pythagorean theorem says that the square of the projected flight radius (cosine) is the difference of the square of the hypotenuse minus the square of the sine. Therefore, the apparent flight radius is the square root of 3600 (60 squared) minus the square root of 36 (6 squared), or the square root of 3564. This means the apparent flight radius is 59.7 feet. The speed would then be 59.7/60 as fast as if it were flying a full 60 foot radius. if the timed speed was 120, the actual speed would 119.4 MPH. Even if you said shoulder high is 4 feet, so 12 feet is 8 feet to high, the actual speed would be 118.9 MPH.
I think the 353' circumference "at altitude" is where the error lies.
You are exactly right Bill. The error was in the second circumference. The difference is much smaller than I originally stated. Getting old I guess and don't use math enough. Thanks for keeping an old engineer honest
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I videotaped this flight. Roy Glenn was flying and he made every attempt for a clean time. You don't have to believe me but I spent alot of years at the carrier circle and Roy's flight was legit. Camera angle is a bit skewed I think and makes it look higher.
Tom
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Here’s a video from 9-19-2021 at our Vintage Combat Festival of the my Slasher being flown by Roy Glenn cruising over 124 MPH, turning and burning! My Fox 36x BB was really singing on the 65% Nitro fuel mix. It took a bit to get the needles setting with all the after run oil in the engine, once the engine warmed up you can here the Nitro crackle. I have to say this was a fun build.
Al
WOW..!!
That's my first look at a combat plane from that era....flying like a plane from the 1980s or later...!!
That's not your "all out speed" prop...is it..?
My [wild] guess is the video shows a 8x6 combat prop in action and your speed prop would be a 7x7...?
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WOW..!!
That's my first look at a combat plane from that era....flying like a plane from the 1980s or later...!!
That's not your "all out speed" prop...is it..?
My [wild] guess is the video shows a 8x6 combat prop in action and your speed prop would be a 7x7...?
The prop is a APC 8x8, and so far the top speed is over 124 MPH that has been repeated on different days. There is more to gain, I just need the time to work on the tune up.
Al
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That's amazing to see an early Combat Special with a 8x8 flying that fast through the maneuvers.
My guess you are pretty close to hitting The Wall at 124 MPH...?
The APC 7.2 x 8.6 might be the ticket. I believe they made that prop for the old Formula One Pylon Racers.
APC has an amazing history of being right on top of an ever changing world of specialized model plane needs.
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That's amazing to see an early Combat Special with a 8x8 flying that fast through the maneuvers.
My guess you are pretty close to hitting The Wall at 124 MPH...?
The APC 7.2 x 8.6 might be the ticket. I believe they made that prop for the old Formula One Pylon Racers.
APC has an amazing history of being right on top of an ever changing world of specialized model plane needs.
(That's amazing to see an early Combat Special with a 8x8 flying that fast through the maneuvers.)
60% Nitro Helps
(My guess you are pretty close to hitting The Wall at 124 MPH...?)
I know there is more by the sound of the engine in song.
(The APC 7.2 x 8.6 might be the ticket. I believe they made that prop for the old Formula One Pylon Racers.
APC has an amazing history of being right on top of an ever changing world of specialized model plane needs.)
They make great props for sure!
Al
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https://spencergoesflying.net/hosted/static_thrust/
19000 for 125 mph and 20000 will get you into the 130s ......... at that rate the 36X is pumping out close to 2 HP and has probably voided the warrantee n1