I bought this ARF last year and have finally put it together. Hopefully it will be just over 100 mph , or more....
Fiberglassed the firewall and secondary firewall, sealed all the hinge gaps on both sides, fiberglassed the center section of the wing. Used 4/40 control rods on the elevator and rudder and 2/56 on the ailerons, got rid of most all of the stock hardware including the control horns that break. Installed a Rossi 53 with a Nelson Muffler.
I tried to get away with running a cable to from the rudder servo to the nose gear however there was way to much drag in the cable and nosegear so that idea was nixed and now the CG is fwd of the required 150mm by 6mm. I will have to add 1/2 oz of reniforcement near the tail because of the extra servo needed for the nosegear
Maiden voyage when the weather turns nice.
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My Speed Demon made me do it!!! <Possessed since 1968> Revver Bro 178
Dude, it's the last week of July. That is your week up summer up there, what kind of weather are you waiting for!?
When you live in the Yukon...........Summer can become winter in about 15 minutes or less , Currently summer is on hold pending snow and storms. When that clears up hopefully summer will return
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My Speed Demon made me do it!!! <Possessed since 1968> Revver Bro 178
Weather was nice yesterday, so after a long preflight I took her up.
It was off the hook, akin to holding a cat's tail and pouring boiling water on the cat.
It was all over the sky. The only time I have ever truly felt during a test flight that I was going to put it in the ground!
Anyway I did cut the power and drop in the pattern for a aproach to a crash , aproach was just nasty, all over the place... I did manage a flare to a landing ( No crash or damage ) and put her back on the bench for looking at the control throws. I set them up per the book but it has way too much aileron............reduced the aileron from 8mm to about 5 or so. Still has quite a bit of aileron during the second flight. Put the elevator at 50% neg expo and that seems to help, but it was mostly the ailerons that were causing the greif, way too fast a roll rate. Anyway after a heart stopping couple of flights, here she is at the field.
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My Speed Demon made me do it!!! <Possessed since 1968> Revver Bro 178
Posts: 6448
Joined: 12/8/2002 From: Valdese,
NC, USA Status: offline
Did you have dual rates set up? I use them for take off/landing and at speed flying with not too much expo for at speed flying. I tend to hit the top of the expo curve at the wrong time and fly much smoother with small throws.
Vicman - No dual rates set up.... almost cost me a plane
Will set them up before next flight and check out if that makes it fly better. To me the plane was not very fast however since I had my hands full at the time I was not focused on speed. Everyone else said the plane was fast....
I will follow your suggestion and not put any expo on the low rate.
Thanks for the help.
Richard
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My Speed Demon made me do it!!! <Possessed since 1968> Revver Bro 178
Posts: 6448
Joined: 12/8/2002 From: Valdese,
NC, USA Status: offline
I have a little bit, like 5% or so just to allow for my heartbeat. On high rate for take off an landing I have about 15-20% but going up past that the curve gets painfully steep fast when you pull hard. After spending some time with the pylon guys and seeing how they set the racers up I turn things way back these days. It's not like I'm doin 3D at 150 ya know? With the F-20 you will be in the 110-120 range pretty easily and all of mine were stable flyers once they were trimmed in and I quit horsing them around.
I set the dual rates at 68% of what I had and found that the plane flys much better with it set on low rates. Made a few flights and never took it off the low setting. Elevator was good as well. Sure slows down fast when the nose comes up.....Made some very nice nose high landings with power on
The suggested throws in the manual are not even close. My ailersons are less than half the suggested throws in the manual now. Even with the dual rates on...flying a pylon circut the stick is only moving maybe about 1mm or 1/16th of an inch.
I need to adjust all of the linkages now and reset the low rates to about half of what I have now....then make sure that I remember to use the switch on takeoffs and landings
Richard
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My Speed Demon made me do it!!! <Possessed since 1968> Revver Bro 178
Thats great news! Be careful not to get to cheeky trying to turn while rolled at slow speeds...it will not come out good.
Split S dives with a 2' off the hard deck flybys will give you sweet dreams.
Thanks for the advice on the turns at slow speed, I usually only fly at full throttle, probably one of the reasons why it was all over the place on the Maiden flight
Split S dives while skimming the runway at full throttle while blasting the theme song to Top Gun!!! now thats what dreams are made of!
Richard
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My Speed Demon made me do it!!! <Possessed since 1968> Revver Bro 178
I finally got the Tigershark dialed in and the fun factor is starting to flow now
Book rates are way off ....The box says " the ultimate high speed adventure ", well they were right. First flight was trying to avoid a full throttle contact with mother earth and stained shorts
Here is what I came up with for control throws for High and low rates. Seems to work great now as long as I remember to flip the switch.
High rates:
Ailerons = 5mm each direction 15% neg expo Elevator = 10mm Up and 6 mm down...50% neg expo, but I am dropping this to 35% neg expo. Rudder = 15mm each direction
Low rates:
Ailersons = 3mm each direction....0% expo Elevator = 4mm up and 2mm down.....0% expo Rudder = 8mm each direction, but I seldom use it...
I flip to the low rates as soon as the plane starts to level off and gain speed and I flip back to high rates as soon as the plane slows down once I chop the power, usually about 4-5 seconds.
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My Speed Demon made me do it!!! <Possessed since 1968> Revver Bro 178
Posts: 6448
Joined: 12/8/2002 From: Valdese,
NC, USA Status: offline
Sounds good. Keep a close maintenance eye on your push rods and you will have a fun plane for a long time. The one I have now has held up for about 4 years. It needs some hearty maintenance though.
Posts: 7865
Joined: 6/11/2003 From: Northridge,
CA, USA Status: offline
I have not looked in this thread for awhile. Yukonflyer, I was surprised to read about yours being so squirrely. Maybe you need a 25 mph wind like the conditions mine has flown in.
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All Forums >> RC Airplanes >> Extreme Speed Prop Planes >> RE: PHOENIX MODELS F-20 TIGERSHARK ? 
RE: PHOENIX MODELS F-20 TIGERSHARK ? - 
, or more.... 
, Currently summer is on hold pending 
