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SM-Extreme F-4 1/9 scale questions

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Old 07-10-2012, 08:10 AM
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DocYates
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Default SM-Extreme F-4 1/9 scale questions

I have one of the first SM 1/9 scale Phantoms which was produced, and flown, as a demo model. It is pretty light, and looks like it was originally flown with no flaps. I am in the process of stripping the finish and applying amore scale paint job and refitting the aircraft for flight. I have not found a lot of information on this plane, but the specs say it will wiegh from 16-22 pounds. I want to install a Wren 54SS (about 18-18.5 lbs of thrust), because it is a sipper when it comes to fuel and it is a super light weight engine.
Do you think it would be adequate, fiorst since this is known to be a draggy airframe and second you will obviously lose some thrust due to the bifurcated pipe.
Second I have never flown an F4, but always wanted one, so this is a cheap way of getting the ride....haha....so I am wondering about the utility of going the extra route, and adding the flaps along with the increase in weight. I want a nice flying sport model not a competition beast, so I would like to stay away from the extra work if it is not necessary.
There have not been many of these mentioned in the forum that I can find so any worthwhile information would be appreciated.
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Old 07-10-2012, 01:49 PM
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Default RE: SM-Extreme F-4 1/9 scale questions

I have one of the Black Bunny Versions of the Small jet. I really think If you keep your weight down your turbine will fly it. But you may experience a longer than normal takeoff roll. Ive read these jets pitch down with flaps..
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Old 07-10-2012, 03:52 PM
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Default RE: SM-Extreme F-4 1/9 scale questions

I have a cheetah 31 pounds of thrust, i now have 7 flight on her and i need all the 31 pound of thrust, this plane is a rock, fly pretty well but need some thrust.
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Old 07-10-2012, 04:10 PM
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Default RE: SM-Extreme F-4 1/9 scale questions

I had been going through the same thought process recently. My X-treme F-4 arrived last month and one of the first things I did was weigh everything so I could decide which engine to use. The ARF and everything I plan to install came to about 20 pounds, less the engine and ancilliaries. My preference was to keep it light and install a 100N engine. With a 100 I planned on using only the two saddle tanks (88 oz.). The engine and ancilliaries weigh about 3#, and the fuel 5#, so take off weight would be 28#. Assuming 10% loss for the bifricated pipe I'd have about 20 pounds of thrust.

With a 140 I'd use all three tanks for 120 oz. of fuel. The engine etc.weigh 3.5# and fuel 6.5#. So in that case I'd have 30# take off weigh and 29 pounds of thrust. The F-4 has a reputation as a power on plane and I fly off of a short runway, so I went with a Merlin 140.

I haven't flown mine yet so I can't speak from first hand experience but I wouldn't consider anything less than a 22# engine. One guy I exchanged emails with said he saw one fly with a 19# Rabbit and described it as unimpressive. If you can keep yours light enough I would think that a 100N engine would work. Find another home for your Supersport.

Joe
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Old 07-11-2012, 04:35 AM
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Default RE: SM-Extreme F-4 1/9 scale questions

That sounds good. I have a brand new K-140 that needs a home, but was worried about the fuel. Looks like the 140 will be the power for this beast.
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