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Showing results for tags 'Speed Mods'.
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I have heard some discussion regarding the advantages or disadvantages of the retractable step. While most will agree it is cool, some disagree as to the advantages. In a recent Facebook post I saw that someone had their vacuum system removed and has the step hanging out without detrimental effect. Before the electric step conversion, I had left my step hanging (original crank equipped aircraft) by accident and recalled noticing because my speeds were lower and the ball was slightly out. Anyway, decided to do some testing on a short trip yesterday and verified that it does make a difference. In fact, it was quite notable when paying attention to the numbers. I’ll call it an average of about 3 knots. I repeated putting the step up and down a few times and it was consistent. I made a rather crude video for those who must see: https://youtu.be/zOD2mXwcOIk. There are two reasons for the significant speed change. One is obvious, it is that the retractable step has zero aerodynamic abilities. It is a large square tube with an equally blunt step. The second is less obvious, but it is the effect of asymmetric drag on the airframe. Those who have left the step out may note that the ball on your turn coordinator will be ever so slightly out of center, requiring a touch of left rudder to counter it. Just like slipping a plane on final induces drag and gets us slower and lower, this slight slip slows our aircraft down. What percent of the drag is due to the step drag vs slip I’m not sure, but it clearly adds up. Mooney’s are especially sensitive to good rigging, as noted by some wide variation in reported performance. Modern Mooney’s have a more aerodynamic step, so Mooney opted out of the retractable step business in the late 60s. I think it would still be cool to have it retract, but it might be somewhat invasive. Anyway, would love to hear from others with detailed side by side speed comparisons of step up or down or on or off. While I am on the taller side, I still appreciate the step and I know my pax do as well.
- 16 replies
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- 5
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- pneumatic step
- retractable step
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I just picked up a 95 Ovation 1. It seems a bit slow to me for an Ovation. Coming from a 63 M20C its plenty fast for now but I've read they should get close to 180 knots true but I get around 175 true. What can I do to speed it up a bit? I heard getting rid of the McCauley three blade for a Hartzell Scimitar and maybe add EI could help. It does have TKS installed which I hear can drop a few knots. Any thoughts?
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Looking to sell my Cherokee. She is unique and a LOT of fun. She can carry full fuel and at least 4 real adults. Because of her Full STOL kit this Piper can fly and glide while at the same time can take off Amazingly short as well as stop on a dime. This Piper had no issues in grass or camping. Price is $52,250 or best offer. Pics and spec sheet are attached. Martin Piper Pics - Underneath and underwing.zip Piper Pics - Mostly inside - seats and panel.zip Spec Sheet - 1965 Piper Cherokee 180 - PDF Version.pdf
- 7 replies
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- 1
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- Cherokee 180
- STOL
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