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Building Tips and technical articles. => ARF'S => Topic started by: Dmitry Minyaylo on November 10, 2020, 10:28:10 PM
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Dear fellows! Im looking for wing dimensions of original flapless Sig ARF Primary Force (SIGCL26ARF). Need wing chord at root, chord at tip, and leading edge sweepback. Can anybody help?
Thanks to all.
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Hello Dmitry;
Are you referring to the ARF kit, or the plans for the kits that Mike Pratt put out? It was never a kit by SIG and no plans offered. I have both and can measure. The ARF kit has a bit different construction that was implemented for production reason, but I think the models are essentially the same. let me know and I'll check this weekend.
Type at you later,
Dan McEntee
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Hi Dan!
I was referring to Sig ARF. Than I found that the short kit from Mike Pratt has a little differerent dimensions (I mean wing span and the fuse length). Please measure both. Also I would like you to measure ARF span and fuse length without the spinner.
Thank you.
Dmitry.
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Hello Again Dmitry;
I just finished checking out and measuring my ARF model, and comparing measurements to the plans for the first kit Mike Pratt put out, ( self produced, not through SIG) and to the last version he was producing.
The ARF kit calls out 50.8" wingspan on the box cover, and I measure 47" from the outside to outside of each tip rib. Both plans call out 51 1/4" wingspan and the tip rib to tip rib measurement is 46 1/2". Root chord is 11 inches and tip chord is 9 inches. The wing is tapered, and both leading edge and trailing edge taper about 1 inch. ARF kit wing area is shown as 500 square inches, and the plans both call out 502 square inches. The wing in the original kit shows just dap strips. The ARF kit has a semi sheeted leading edge, and the later kit plan also shows a semi sheeted leading edge. The sheeting goes back about half way to the spar. I would prefer my kit wing to be built the same way. Kit plans both show a 4 inch plastic SIG bell crank, but I believe the ARF has a 3" metal bell crank similar to a Perfect or Fox metal unit.
fuselage length on the ARF is 34 inches from the back of the spinner to the very back end of the fuselage blank. Overall length of the ARF is 39.5 inches from tip of the spinner to the back end of the rudder. The plans length is 40 inches on both versions. The design is an inline design with thrust, wing and stab all in line.
All in all, I think there is very little difference between all three. The differences in the ARF are probably just there for production purposes. they are no longer in production and I doubt they ever will go back into production. I have Mike's original self produced short kit with plans, and those plans are what is listed on the PAMPA plans list, as it was published in StuntNews. I also have a copy of the last kit he has self produced and there are minor changes to the plan and to the laser cutting of the parts. I'm sure that you will like any of these versions that you could get you hands on.
Type at you later,
Dan McEntee
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Hello Dan!
Thank you very much for your response. This info is very helpful.
Thanks again.
Safe and soft landings!
Sincerely, Dmitry.
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Hi Guy’s,
If your looking to build a P Force I have the plans and book in stock. The P Force is going through a redesign at the moment to make adjustments for heavier wood. The biggest problem is the weight of the Balsa and I’ve changed a number of the wood thickness to make up the heavier Balsa wood. The model should still build in the mid 30-35 ounce range which is about ideal for the P-Force. The ARF versions built up at 40-45 ounces but still flew ok, just didn’t have the snappy corners.
Later,
Mike Pratt
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Hi Guy’s,
If your looking to build a P Force I have the plans and book in stock. The P Force is going through a redesign at the moment to make adjustments for heavier wood. The biggest problem is the weight of the Balsa and I’ve changed a number of the wood thickness to make up the heavier Balsa wood. The model should still build in the mid 30-35 ounce range which is about ideal for the P-Force. The ARF versions built up at 40-45 ounces but still flew ok, just didn’t have the snappy corners.
Later,
Mike Pratt
Is tis because lighter wood is too hard to find?
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I still have my P-Force I built from short kit I got from Mike's first wife at VSC years ago. Needs a recover job after Sandy the toy poodle did her dance on it at Topeka contest. And yes the super light balsa is getting scarce as industry is using it up to satisfy the greenies that believe wind power is the answer. I am not a light builder and IO think mine weighs in the upper 40 ounce range and flies better than I do. Mine is powered with an LA 25 with stock muffler on uniflo tank, prop is MAS 9x6, 10% nitro 1/2 & 1/2 oil. 60 foot cable of .015 diameter center of plane to center of Fancher handle. D>K
Is that enough detail as I look at the set ups of the electric people. H^^