orthobird

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any suggestions on a fast plane
i want to be able to go not more than 120 or 130 mph

thank you

evan-RCU

Why limit yourself... these'll do 200... both and others are for sale.

orthobird

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way too fast for me.

daven

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A great planes viper ARF and a .46 sport motor will get you right around 120 mph.

freakingfast

My Feedback: (3)

I have to agree. It's a good inexpensive and easy way into speed. Real smooth flyer.
I just sold one RTF with a Webra 55 on the nose. Hundreds of flights.

They do need some mods:

Replace the stock wheels, because the stock wheels last about halfway on the first takeoff.

The Viper is a very good plane and with some strength and incidence mods it can become fabulous. The V tail shimmed up at the rear, I start with .040". You'll know when it's good when the tail's control surfaces are about flush when trimmed for level flight. Failure to fix this incidence problem could lead to servo failure or shorten battery's run time due to the constant load in flight. Just like a stalled throttle servo can do to a battery.

Use a plastic push rod (like Goldenrod)and plastic ends on the throttle control, this will reduce the servo killing vibration.

Add a 1/16" x 1/2" piece of plywood to both sides of the upper edge inside of the rear servo/batt compartment.

You won't like this part, I remove a strip of covering material on both sides of the fuse to allow me to CA a strip of .014"X 1/2" carbon fiber 4 1/2" long that starts 1 1/4 ahead of the leading edge of the wing and running just under it. And again a 7" strip that starts 2" ahead of the leading edge of the V tail and running just under it. Then recover with Monocoat. I use BLUE Locktite (removable) on the steel wing screws. I use Locktite each time I put the wing back on.

Before installing servos, drip in thin CA into all the little gaps around the wing mounts, formers, inside firewall and bulkheads(do this outside in the sunlight and fresh air).

Glue the fuel tank hatch down per instructions, don't be temped to screw it down (it's a box form strength thing).

Don't spin the starter and slam it into the spinner to start. Back the prop off compression, place stater cone on spinner and press the trigger. Otherwise you could pull off the firewall.

All control deflections from flush are ¼� up and down (½� total throw, a bit radical but fun).
V tail mix instructions (JR): Set elevator at 125% of rate (or travel) and 50% expo. Rudder 125% rate, no expo.
You want responsive rudder for landing heading control. Aileron rate 100% no expo. Aileron response is quite docile.

Be ready to add a bit of up or down trim on first flight.

Use a timer on your flights,(start with 4 minutes) this lets you dictate engine shut off to set up for planed landings, you wont be landing this puppy engine on unless you have a drag strip handy.

Lastly, and most important! After the first flight, Get that silly grin off your face, no one else will understand.

speedracerntrixie

My Feedback: (29)

Hi guys, I am trying to get a pipe set up on an engine and because I don't have alot of experience with tuned pipes I am looking for some help. here is what I have. Rossi .61 5 port long stroke with a Picco 80 DF carb ( 12mm) The exahust port has been raised .040. That gets the duraration up to 170-175 degrees. Running an Enya 3 plug and 15% nitro 18% oil ( partal castor ). Last time I raced the airplane was with the Rossi 10 mm carb and a different pipe. The pipe was a full length Macs header and Macs muffled pipe. prop was an APC 11X11. I did not tach the engine but was reasonably happy with the speed. Took a first place finish that day. To protect my points lead I went searching for some more speed. Got the bigger carb and set out to make a better pipe. The new header is 7/8" inside dia that matches the exahust port wheras the Mac's header was only 3/4". The new pipe's body ( area between the forward and aft taper ) is 2" longer then the other pipe. I set the header length so that the distance from plug to forward taper is the same on both pipes. Overall the new pipe is 2" longer then the old pipe.


Results. On the ground with an APC 11X11 I got an even 12K. I flew and saw no real speed increase. Bolted on a 11X12 and set the needle to what I thought would be really rich knowing it will unload and lean out in the air. It did and the speed went up a little. My concern is that the engine seems overly rich to keep it from running too hot. Not sure what adjustment to make from here. Thanks for ant help you can offer

evan-RCU

JB Weld a smaller diameter piece of tubing to the end of the pipe to increase the tank pressure. Look at the pipes on my twin delta.

speedracerntrixie

My Feedback: (29)

Tank pressure was a thought. I was going to try adding a second fiting to the pipe and using a T before the tank. Seems like I have good fuel flow as I can richen to a 4 stroke. To me it is acting like the pipe tuning is short but it is not any shorter then the privious pipe. Would the larger dia header have an adverse affect?

freakingfast

My Feedback: (3)

11 X11 is a lot of prop even for a 61 Long stroke. If it unloads it's amazing and you are doing well. I'd say your at the limits of the engine.
10X10 was the limit for a OS 70 heli on tuned pipe, but I was turning more rpm too, your turning in the basement for a patten engine.

flycatch

My Feedback: (26)

Get yourself a jet.

orthobird

My Feedback: (1)

not for me.
i see those utube vids
people with fire extinguishers on side.

plus,
when you say crash and burn,
the jets really do so

LOL

orthobird

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i saw that plane

i have never flown a plane with that tail config?

how is that?

rudder / elevator??

flycatch

My Feedback: (26)

No guts no glory.

freakingfast

My Feedback: (3)

No big deal, just enable V tail mixing. Very smooth at speed, but rudder effect is low at reduced speed so if you need correct alignment to the runway, don't wait too long or use too little stick.

Dave

FOX MK-II

WWW.RCMPLANS.COM

PLAN # 1338 (sport)

OS .35 AX ENGINE 100+ MPH

Desertlakesflying

My Feedback: (28)

Hangar 9 Mustang 60 size...(Marie version)....OS 120 Surpass II, 15X7 3 blade...... 110mph level flight

vicman

My Feedback: (10)

V-tail is not a big deal, you most likely won't be able to tell a difference. Viper or any other Quickie and a decent .46 will get you some good speed.

skull1971

120-130 is not fast, I have a Ultra Stick 40 that can do that!! ( OS 91 with a Dub pipe, and everything not needed gone ) just don't try to turn!

speedracerntrixie

My Feedback: (29)

Gave it another try today. I think it was a combination of a bad needle setting and the carb was not all the way down on the O ring. Big difference. Got it to turn an 11X12 in the powerband. tried a 12X11 in hopes of better pull in the turns but no go. the 11X12 got me in the 170 mph ballpark. Going to stick with this setup for next weekends race.

vicman

My Feedback: (10)

Awww Cmon Eric? Seems like you forgot how magical it was to go over 100.
I can remember daydreaming on Monday how cool it was to fly my Kangke F-20 the previous Sunday. I thought that thing was insane fast at 106 from angles 11.

orthobird

My Feedback: (1)

i like the look of that one.
so 3 channels or 4 channels?

aileron, elevator, throttle?

freakingfast

My Feedback: (3)

The V tail still gives you elevator AND rudder, so four channel is best.

vicman

My Feedback: (10)

4 ch
Not sure what kind of Tx you have but make sure it will do V-tail mix.

orthobird

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yes it can.  jr 9503

vicman

My Feedback: (10)

Viper will be the quickest step into decent speed as mentioned before. After the fuse snaps you can get a good fuse from me or Daven that will work with the Viper wing.