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Indeed, seriously considering this myself now, they look excellent. Can't wait to hear how they perform.
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Well done! Looking forward to flight reports.Comment
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Beautiful work. We used to make Hoerner and "anti" Hoerner tips on RC gliders back when people still built RC planes (40 years ago). With very high aspect ratio wings they were a very small percentage of the wing. On a Bearhawk, who knows, maybe there will be a measurable result.
Either way, looks cool and I want them! Very nice.Comment
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Those are beautiful, exactly what I want to do. Did you say they extend 16"?
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Battson, Do you have any pictures of how you fastened them? AL reinforcing strip glassed into the tip where the screws go through? Used the same nut plates the were installed for the factory tips?Scratch Built 4-place Bearhawk. Continental IO-360, 88" C203 McCauley prop.Comment
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In case anyone wants to know how many hours of sanding I 'logged', about 14 hours of sanding with 80 or 120 grit.Originally posted by whee View Post
Then once over lightly with a 220 grit, but the primer filled all the scratches.Comment
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They extend 15 inches, with an inch (roughly overlap), so 16 inches total. Bob said 15 inches was the maximum he would endorse.Originally posted by rodsmith View PostComment
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Bob recommended an additional fibreglass tape to strengthen the edge where the screws go through. You have seen I've used countersunk machine screws (#6) with wide area washers, they go into nut plates which attach to the wingtip rib. At first I was concerned about strength, but after putting the screws on and applying some force, they are a lot stronger than I ever expected. They don't flex at all, not even a fraction. I am confident they are strong enough.Originally posted by whee View Post
I will be pulling a set of moulds off these tips, after flight testing confirms they work as desired.Comment
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Came out great, look forward to hearing your flight report.Comment
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First flight completed.
Of course we are testing them slowly, but we found them to fly well with no bad news. They seem ridged in flight. Cruised at 130 KIAS (about 140 KTAS) and they gave no trouble. Roll control was better than ever in fact, because I have rigged the aileron differently. Ask about that separately, that is a real gem.Comment
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Battson, I hope you are able to make some comments on top end and bottom end performance. Was that your primary motivation? I suspect the simultaneous change in aileron rigging may mask some effects.Comment
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We were hoping for better STOL performance first and foremost. We will certainly be testing for it.Originally posted by nichzimmerman View Post
There's a small chance of getting help at the top end in terms of stability, and even speed... but I feel it's unlikely. Time will tell. They also look great in my opinion, another secondary benefit.
Of course wingtips seldom make a huge difference, but we will know for sure very soon.Comment
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Glad to hear the first flight went good and I look forward to reading about you further testing. I’m really interested to hear about the aileron rigging so I hope you make a post about that soon.Originally posted by BattsonScratch Built 4-place Bearhawk. Continental IO-360, 88" C203 McCauley prop.Comment
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And the best part is that the man has his steed back in the air! That was a lengthy refit from the sound of it .Comment
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We are getting notably shorter takeoffs with the Trailblazer prop and Hoerner wingtips. The mods were installed at the same time so I can only comment on their combined effect.
When the plane is emply it's less than 3 seconds from standstill to breaking ground, and under 100 ft roll. Open the throttle, pop the flaps, and it's clear. Initial climb rate is over 2,600 ft/min. Nose angle to the horizon is 35 degrees, airspeed showing 60 knots and AoA showing about 5 degrees. It's a rocket ship. This is the bigger 4-place with a heavy fuel injected motor and heavy bushwheels. It will fly at over 40 degrees to the horizon at 50 knots, but the rate of climb reduces to about 1,900 ft/min.
Loitering flight at 38 KIAS with 3 or 4 notches flap gives me total control, even in medium turns. At about 45 KIAS I can slip very aggressively, looking out the side window at the runway, descending at about 1,500 ft/min. AOA is still in the green during level flight at that speed, which means the wing is nowhere near the stall. The plane is more steady than ever on approach, airspeed about 38 kts indicated when light, about 42 KIAS when loaded to max weight. Touchdowns when unloaded are about 33 KIAS, I've done hours in the circuit and it's very consistent. The true speed is between 35 and 37 KTAS at sea level.
I guess the only area which hasn't improved is the cruising speed. We can still keep up with a Maule or C180 but it uses more fuel than before. Lean of peak cruise is about 112 KTAS at low level, 125 KTAS at high altitude. It would go faster if I wanted to burn more fuel. I figure this is about 5 KIAS slower than our original airspeed before any modifications. Mods which could slow it down 31" tires, oversize tailwheel, vortex generators, and 16" extended wingtips. But it still cruises fast enough for me.Last edited by Battson; 10-04-2021, 06:39 PM.Comment
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