Wheel Spats - Are they worth the trouble?

[facthunter]

Geez David. Some of us actually use a tyre gauge. It and the airhose are extremely difficult to use under wheel spats. It's a pain in the a**e. I used to have to loosen the spat slightly on the Citabria to get access.

 

Unless your plane is pretty slippery and has a good cruise speed the spats don't add much speed

 

Let's face it .they can look realy sexy. That's the main advantage. As for getting mud etc in there, that's a real problem too. Nev

 

 

[Tomo]

Pays to roll the aircraft a bit to check all the way around a tire under a spat. I've heard of the odd occasion of a blow out due to a flat spot on the tire from someone locking up the wheel.

 

 

[facthunter]

Good point, Especially if you have good brakes like Clevelands and operate on a sealed strip. Nev

 

 

[turboplanner]

From my farm days, a small horizontal plate behind the wheel will stop the mud and cow dung flying up so a set of those for the paddocks, and spats for the bitumen.

 

Plate size, tyre width x approx up to 2:1 length.

 

 

[turboplanner]

Pays to roll the aircraft a bit to check all the way around a tire under a spat. I've heard of the odd occasion of a blow out due to a flat spot on the tire from someone locking up the wheel.

Well Tomo, if you can flat spot a Jab I'll give you a bottle of champagne, others I'd agree with.

 

 

[Tomo]

Well Tomo, if you can flat spot a Jab I'll give you a bottle of champagne, others I'd agree with.

Actually with Jabs it pays to even have a closer look than usual, as they scrub out on the inner side of the tire, particularly if operated in high crosswinds fairly often, and off tarmac.

 

Just slightly embarrassing taxiing out and then getting stuck on the spat.

 

 

[Guest russ.mullins]

Keep the input coming, I'm loving the ideas. My Cheetah cruises as 110kts, so maybe the spats are contributing to that speed. After reading all of the comments I'm leading towards the idea of leaving the front spat on to keep the wheel aligned and slipperier in flight, and replacing the main spats with flat mudguards. The thought behind leaving the front wheel spat on is because that wheel has less stuff under the spat to go wrong (brakes) and has never caused me a problem, it usually arrives on the deck fairly gently and has never punctured, I suppose its only a few bucks to get some alloy plate and manufacture the mudguards, and as turboplanner said if I ever get hangered at a bitumen strip I can drag the spats back out. Problem for now is that my local airport/strip has no hangers available so I'm hangered at a bush strip thanks to the kindness of the farm owner otherwise the plane would be out in the weather. The benefits I see with mudflaps are:

 

1. I can check the wheels, brakes and tire pressures and pump up the tires with ease

 

2. I keep the flying dung off the wings

 

3. Maybe I get the weight down a bit

 

4. They won't fill up with mud

 

5. They won't come loose or tear off in rough terrain

 

Disadvantages I see are:

 

1. They will reduce airspeed, not sure how much

 

2. They might look pretty stupid

 

3. They might effect flight characteristics

 

Happy to receive feedback !!

 

 

[turboplanner]

Actually with Jabs it pays to even have a closer look than usual, as they scrub out on the inner side of the tire, particularly if operated in high crosswinds fairly often, and off tarmac.Just slightly embarrassing taxiing out and then getting stuck on the spat.

I try to land straight Tomo

 

 

[Guernsey]

I try to land straight Tomo

I agree Turbo to a certain extent however, once the aircraft is on the ground and running straight, a strong crosswind coupled with under pressure tyres (lazy people) the sideways pressure will cause uneven wear and could even roll the tyre.

 

Alan.

 

 

[Guernsey]

As tyres tend only to go flat on the bottom, I don't see how they stop you checking tyre pressures. You can usually judge pretty closely by visual inspection, without need of a tyre gauge.

Don't quite agree there David, some tyres on some aircraft look the same visually but can have as much as 5 pounds difference in pressure.

 

Low pressure in tyres can be dangerous however imbalance in pressures can be worse.

 

Alan.

 

 

[Guernsey]

You are correct Russ when you state that with castoring nosewheel ( Morgan Aircraft ) the spat would help to keep the wheel straight into the airflow.

 

Alan.

 

 

[Tomo]

I try to land straight Tomo

Don't we all, still not going to stop me from checking the whole tire.

 

I've never had a tire go on me, but seen it a few times.

 

 

[eightyknots]

best of both worlds?

I have often thought about this kind of arrangement but I have never seen one until you posted this picture. I'm sure it must add a few knots to cruising speed for no extra fuel. What plane is this on?

 

 

[fly_tornado]

they where on a yak 54. although that photo is a giant RC model.

 

 

[kgwilson]

Russ, How about drilling an inspection hole in the spat (say 25mm or 32mm) so you could check the tyre pressure and add air when necessary. A blank grommet could be installed to cover the hole if you want. I presume you have drum brakes. The Matco discs I have are easy to inspect as the external disc and caliper are on the inside where the spat is cut out around the undercarriage leg.

 

 

 

[facthunter]

KGW that has been done and will work if the wheel is in the exact right spot. If you borrow someone else's airhose the angle etc may not work. On a slope or in soft earth moving the plane, (unless it is very light) is difficult to get it in the precise spot.

 

Cleaning the undersurface of your wings is not easy or fun especially if they are close to the ground.

 

The deflector plate seems like a good idea and if aligned properly should not cause any significant drag.

 

This is an area where something could be done that is practical and safe. Who knows, maybe this will take off. Don't worry about the looks.( If I did that I would have slashed my wrists years ago). Nev

 

 

[Guernsey]

I wish I had taken a photo of that Foxbat with the horizontal deflection plate.

 

Alan.

 

 

[dazza 38]

I wish I had taken a photo of that Foxbat with the horizontal deflection plate.Alan.

It's OK Alan.In the January Sportpilot , page 13 has a photo of a Foxbat with them fitted every RAA member will see them .They look OK.Sort of.

 

 

[Powerin]

Perhaps we need retractable spats that can be activated same time as flaps. Don't ask me how they would operate, where they would be stowed, or anything else for that matter. I just came up with a numbskull idea - up to you guys to figure it out!!! Can it be done?Pud

I've wondered about this too Pud. I've been trying to figure out if it would be possible to make a fully enclosed spat that covers the whole wheel. Perhaps a clamshell type arrangement that you close over the wheel in flight. Of course this brings up the same problems as retractable gear in that you have to remember to retract the spats before landing. But still, it has the potential to reduce drag without the weight and complexity of RG.

Edit: damn.....LoPresti has already invented it.

 

 

[Guernsey]

It's OK Alan.In the January Sportpilot , page 13 has a photo of a Foxbat with them fitted every RAA member will see them .They look OK.Sort of.

Thanks Dazza.

 

Alan.

 

 

[jetjr]

Another idea here

 

http://www.leggott.flyer.co.uk/trim.jpg

 

http://www.leggott.flyer.co.uk/WHFAIR1.JPG

 

 

[facthunter]

powerin, you can design the retractable spats to be able to land on if they don't retract. You have parts that break away.

 

eg. The Dougas DC-9 lands with the gear doors down after emergency extension of the landing gear. The projecting part just wears/tears away. Nev

 

 

[dazza 38]

In reply to the original question- "Wheel Spats-Are they worth it ? Yes - if fitted to aircraft like Vans RV's, Cirrus, Cessna Corvalis etc. No- on aircraft that cruise at around 100 knots or less.

 

But they do look sexy.

 

My 2 cents worth.

 

 

[jacko]

Hi, chasing wheel spats for a airborne XT trike if anyone has a set:)

 

Cheers.

 

 

[Old Koreelah]

Spats and other streamlining topics were discussed in this thread:

 

Spats