Speed mods
Yeah I know I just started flying mine....but, have started wondering what mods here and there can be done to reduce parasitic drag. Aside from the standards (being the PVC lift strut fairings and wheelpants) what little mods make a difference? IE: Gas cap fairing, horizontal stab strut fairings, fairing the landing gear legs, etc. I aint thinking about doing a Klaus Savier with mine but thought I'd toss the question out?
Now you're talkin my language!! Whatever changes you make please be sure to test before and after under controlled conditions so that test data is valid.
I wish someone would tape over the hole just under the spinner of the newer cowl to see if it's even needed. That could help speed, but I'm more curious about whether it is needed for cooling or not. I suspect is not.
Wade, you have strut fairings but no wheel pants, correct? What sort to top and cruise speeds are you seeing?
Alternative wheelpants?
Wade,
Since you don't have wheel pants on yet, and you're interested in improving speed, you might consider some alternative wheelpants. The standard Kitfox wheelpants do not fair the brake caliper for the bottom section of the gear leg. I suspect this compromises the speed gain a measurable amount. I am installing 5" wheels and Van's RV pressure recovery wheelpants on my Super Sport, then have 8.50" tires mounted on the 6" wheels that came with the kit that I can install when i want to go land on sand bars and river beds. Details on my setup here.
If you wanted to keep the 6" wheels & tires you might be able to fit a set of RV-10 wheelpants, food for thought. They are noticeably larger though, I'm not sure how they'd be aesthetically.
From what I could tell the Kitfox is already the fastest tube & fabric option available. Reducing drag to make it even faster is an area I'm interested in. Since we both live in the same area perhaps we can collaborate on this.
BTW, Chapter 105 has a state-of-the-art prop balancer system, details here. I'm anxious to start doing Rotax installations so let me know if you're interested. I've balanced over seventy props so far with good results. DSS Micro uses us as an example in all their OSH seminars. Sorry, didn't mean to hi-jack this thread!
Aesthetically, wheelpants are gunna be odd on my plane unless I put shark's teeth on the front of each...
I brought the engine up to 5600 at just about 5000' and saw the speed hit 130 indicated. gps said 136 mph with a little bit of wind behind me. from what I could tell, the wind was just about 6 on my tail from flying into it. Pitot seems to be working very accurately above about 50 mph.
Randy, yeah I'd like to do a dynamic on the rotax. Will be joining 105 now that I have some time on my hands (and $).
Naw, it'll look fine, just paint 'em green to match. Of course sharks' teeth would be kind of cool!
130 mph indicated is pretty good, especially without wheelpants! Kitfox Aircraft lists top speed as 125 mph, not sure if that is with or without wheelpants, official specs here. For testing purposes though TAS should be used, that'll eliminate any wind factor.Originally Posted by wadeg
What is your indicated stall speed, both solo and at gross?
Wade, you've already discussed the wheel pants so I'll add that the jury struts can be streamlined and not sure from your photos if your horizontal stabilizer has streamlined struts or not. Those are two easy mods.
Another cheap fairing is the strut to wing junctions. I know Murle Williams has a set of plastic fairings that are easily fitted and painted for that area. John may also have them available but not sure. You can check and see.
Also the fuel cap fairings are interesting little creatures. How much speed you will pick up is hard to say but they work wonders for reattaching the airflow around those nasty round caps. The caps disturb an area of the wing that makes a triangle about 1.5 feet wide by the time it hits the flapperons. That's a lot of wing area disturbed times two caps. Well worth the effort.
The landing gear is a harder fix. You really have to fair in the gear before covering the fuselage and painting.
Also mounting the com antenna inside the tail helps but we're nit picking on that one. The largest return on investment for any model Kitfox is streamlining the struts. 8 to 12 mph is the norm for increase here.
You've got a fast Kitfox already but there is more speed to be found. Just have to weigh the time and effort to find it. With the price of fuel lately it is getting more appealing to try.
Steve
I Don't Know, Wade
You have done a superb job on the paint and theme of your plane. As an old Viet Nam dog who was around lots of the FAC planes, your's looks great. But you need to prioritize your objecitves. Are you willing to sacrafice a knot or 2 to blow the historical visual of your craft? As one who has as an Air Medal from that era, I am crazy about your plane, and can report that I have never seen one in that uniform with wheel pants. But if speed is the ultimate goal, then by all means, go for it. I'll just learn to appreciate a little different uniform.
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