Gear Drag

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Gear Drag

Postby EchoWhiskey » Sat Nov 03, 2018 7:27 am

This video is a mind blower,

The drag on a rod is almost 10 fold to an airfoil

https://www.youtube.com/watch?v=ftq8jTQ ... e=youtu.be

Why not install airfoil fairings(vocab?) on the gear to reduce drag?
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Re: Gear Drag

Postby BDA » Sat Nov 03, 2018 11:29 am

Alan Ronk did that several years ago in Aus. Says he loves it

Look him up on Facebook
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Re: Gear Drag

Postby BDA » Sat Nov 03, 2018 4:18 pm

Better pictures of allan’s plane

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Re: Gear Drag

Postby SheepdogRD » Tue Nov 06, 2018 10:37 am

I'm not on Instagram, so I can't see what's presented there. For those in the same situation, here's some information I saved about 18 months ago:

Allan Ronk bought his SS through Steve Henry, and built it in Australia. It's VH-YOS. The covered landing gear and faired shock strut are only two of the many modifications he made.

VH-YOS-14.jpg


VH-YOS-08.jpg


VH-YOS-05.jpg


VH-YOS-17.jpg


VH-YOS-12.jpg

Here's a Western Australia news article from November of 2017: https://www.abc.net.au/news/2017-11-22/hand-built-fabric-aeroplane-hunting-for-gold-pilbara/9163602.
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Re: Gear Drag

Postby jzawodn » Sat Jan 05, 2019 10:51 pm

Did he ever discuss the improvements in cruise speed he saw?

I'm sorta tempted to try this, assuming I ever find enough spare time...

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Re: Gear Drag

Postby Tralika » Sun Jan 06, 2019 12:30 pm

I've been thinking about giving this a try as well. I left my gear uncovered with the theory that I want to see any cracks that start to develop rather than having to wait until the gear fails. I have the Extreme Gear on my Highlander with three tubes and 6" longer than the standard gear. That's a lot of drag. I have lots of fabric left over so I may just cover the gear and not paint it so I can do a test flight and see if there is much difference. If the results are positive I'll have to weigh the advantages against the risk of an undetected crack in the gear. I'm not aware of any problems with the Extreme Gear but more research would be needed.
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Re: Gear Drag

Postby danerazz » Sun Jan 06, 2019 6:06 pm

I’m not going to say that not cover your gear to look for cracks is wrong...but...by that logic you shouldn’t put a cowl on, or cover the fuselage.

I think there are better reasons not to cover your gear (lazy, looks cool, operate on terrain that is likely to punch holes in it) but unless you are REALLY pounding on it the crack issue should not be a serious consideration.

YMMV
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Re: Gear Drag

Postby BDA » Sun Jan 06, 2019 10:34 pm

I have had many (half a dozen or more) friends had gear legs fail leaving them stranded on a glacier or river where walking out was not an option.
Failed due to cracks from previous abuse.

Not saying you will always catch a crack, but if covered, you dont have the chance to look.

I will try some aero on the tubes at some point but not going cover the welds for that reason.

When I do my preflight, I dont lay down and inspect every weld, but I do look for rust stains at the welds, cracks usually leak rust.

And at annual, all welds on the gear are crack ckecked carefully.
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Re: Gear Drag

Postby Tralika » Mon Jan 07, 2019 12:31 pm

I have similar experience with gear failures. Never happened to me but I know several people who have and mechanics shown me cracks in gear legs discovered during inspection on several aircraft. I know there have been gear failures on Just aircraft but I don't know of any that resulted from undetected cracks. My gear, like most of the Just aircraft, are powder-coated which can hide cracks and corrosion. I like the powder-coated airframe but that is one of the drawbacks. I would like to keep the gear legs uncovered but if the drag reduction is significant I may do it.
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Re: Gear Drag

Postby SheepdogRD » Mon Jan 07, 2019 1:35 pm

Maybe an option here would be to create a removable aerodynamic fairing that would allow for crack-checks at maintenance intervals. Perhaps some epoxied-on fittings would provide mount points that wouldn't obscure any welds.

I haven't seen the Beringer Alaskan gear fairings except in pictures, but I suspect they're removable. It would be interesting to get a report from a Beringer user on how much the fairings helped.
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Re: Gear Drag

Postby BucF16 » Mon Jan 07, 2019 2:43 pm

Go over to Mike Patey's YouTube channel and watch him build the fairings for Draco. Of course he has the time and resources, but Carbon-fiber fairings would be my choice.
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Re: Gear Drag

Postby Tralika » Mon Jan 07, 2019 5:48 pm

Carbon fiber would be nice. I've made small fiberglass fairings which were pretty simple but I've never worked with carbon fiber. I think the learning curve might be pretty steep and expensive. I thought about making gear leg fairings out of fiberglass or aluminum. The advantage over fabric is making the trailing edge aerodynamic for less drag. With fabric the shape will match the round rear tube causing more drag but less drag than three round tubes. I'm concerned about weight using aluminum or fiberglass but it might be worth some experimentation. I think attaching the fairings to the gear legs with adel clamps would work fine. I guess the thing to do is make a template to determine the overall size of the fairing and calculate the weight in aluminum and fiberglass. Oh Boy, another project!
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Re: Gear Drag

Postby BDA » Mon Jan 07, 2019 6:39 pm

My pacer had 3” long aluminum sheet metal angled trailing edge off the back tube that I think at one time had been fabric covered.

But when I had it the rest of the gear legs were wrapped in sheet metal with screws.
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Re: Gear Drag

Postby Tralika » Mon Jan 07, 2019 9:04 pm

My Stinson had single piece aluminum gear fairings that wrapped around the gear and were secured at the trailing edge with screws and tinnerman nuts. There were formers on the gear to maintain the proper shape and the fairings attached with a few screws. I'm pretty sure something like that would work on the Highlander gear. Not sure what gauge aluminum they were made from. I'd be inclined to try .020. I'll have to make a template if I cover the gear with fabric so I guess I'll see how big a piece of aluminum it would take.
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Re: Gear Drag

Postby av8rps » Fri Feb 08, 2019 10:11 am

I remember reading somewhere on this forum that Steve Henry gained 10 mph by covering the gear legs on his Highlander, so I covered mine with fabric. I just wrapped the leg, but in hindsight should have probably streamlined the leading and trailing edges for more effective drag cleanup.

I have never done a real serious test of mine, but believe I gained about 8 mph. With an uncovered gear at 5500 rpm it would go 108 mph, and now it will go 115mph at the same power setting. (Fwiw, this is with the larger 8.50 tires and a stock 95 hp 912uls turning a 70 inch 2 blade Sensenich carbon prop). They also say a cleaner airframe will climb and cruise better, or more efficiently than a dirty airframe. So there are most likely benefits like less fuel and longer range I will enjoy from this simple option.

If I were building another Highlander I would definitely put some sort of covering on the gear that would be removeable for inspection. I'm not hammering my plane like a lot guys do in the back country, so I'm ok with having it covered.
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