How many knots do you loose when taking off the spats

[Guest Robw]

Hi,

 

We took the spats off our J160 main undercarriage for the winter so they wouldn't fill up with clay. We can't really see the plane being any slower. Has anyone done any testing to determine if and how much difference there is in airspeed with spats on or off?

 

Cheers,

 

Rob

 

 

[Ultralights]

with our tecnam P96, and our Jab LSA, removing the spats made NO difference at all. not even in fuel consumption.

 

 

[Guest check-in]

I took the spats and the gear leg fairings off my Sonex and to add insult to injury fitted larger diameter wheels. I have been unable (too lazy?) to accurately determine any difference in speed but even if it is say 2 or 3 knots, a small price to pay for better access to the wheels to monitor condition, keep clean etc.

 

Back in my misspent youth when I had to fly fixed gear Cessnas for a living, whenever a nice one was imported from the USA, the first thing to be removed was the spats. They may look horn, but just a load of trouble in the bush.

 

 

[Captain]

Rob,

 

There was a good discussion of this subject about 18 months ago with lots of feedback from owners. Suggest you do a search for that, as well.

 

Hope this helps.

 

Regards Geoff

 

 

[Guest Robw]

Thanks Captain,

 

I found the thread. http://www.recreationalflying.com/forum/jabiru/2240-what-speed-facts-spats.html.

 

Didn't look hard enough yesterday to find an existing thread. I'll leave the spats off :-).

 

Rob

 

 

[Guest watto]

We took the spats off our 230 and can see no difference at all, and as it was pointed out now have better ability to inspect, clean and adjust brakes etc.

 

 

[Guest Qwerty]

I put spats on my Lightwing to stop mud and cow dung from being splattered allover the place?? I'd rather spent 5 min removing spats occasionally to access the brakes that spend hours and hours removing airblast dried mud and dung from my paintwork.

 

I guess I use different strips to the previous posters. I have never had trouble with clay.

 

 

[Yenn]

My spats are very close to the wheels and open on the outside, They make a small difference to speed but the main advantage is they keep th wet, sloppy cow dung off the wings. I can still check brakes and pressure without any removal.

 

 

[Vev]

Hi Rob,

 

 

I have played around with various combinations of spats/wheel covers and found that you may lose 1 or 2 knots if remove the spats.

 

 

Interestingly I found my front spat worked in some conditions like a servo on my rudder and wouldn’t allow the ac to bank and remain in coordination as well as it would without the spat … I was working the rudder all the time and once I removed my front spat it made my 160 much nicer to fly as it remained in coordination without me having to tap dance on the pedals.

 

 

The other combination I have tried was to buy a set of wheel covers from the UK (Instrument panels) which seemed to give me the same speed as the spats and where fantastic for dirt strips and a little lighter too.

 

 

Currently I have settled on a wheel cover on the front and the Jab spats fitted on the mains when on my home strip (Tyabb) …. I fit the wheel covers if I’m doing dirt strips.

 

 

Hope this helps?

 

 

Cheers

 

Jack

 

 

[winsor68]

:laugh:If you put your knots in a bottle or similar you should not lose them when you remove your spats...to be sure to be sure...

 

 

[Modest Pilot]

I got approval to build proper 3.7:1 teardrop spats as per "Hoerner" instead of the Jabs mudguards. Worth 3-4 knots.

 

Performance now with a Sensnich 60x56 prop at 600kg:

 

Max Speed: 140kn @3100rpm

 

2800rpm 1000ft 19lt/hr 121kn Egt 690c

 

A bonus was that you can exactly trim the rudder for zero yaw on the Dynon. (but only a for one rpm eg:2800rpm) by slotting the attachment holes on the front spat. Result no more out of balance fuel.

 

 

[BigPete]

Don't be so modest, Modest Pilot. Show us the photos. :thumb_up:

 

regards

 

:big_grin::big_grin:

 

 

[Modest Pilot]

Hopefully a picture will appear in my profile

 

 

 

[Vev]

Hi Modest,

 

 

Your pic in your profile is too small … love to see your spats more clearly, can you try and post a larger picture?

 

 

One of the things I tried was to fit a small trim tab to the back of my front spat, although, like you, it only really worked at one power setting, which I set up at cruise.

 

After I took the front spat off and fitted the hub cap the ac became coordinated at all power settings.

 

 

Cheers

 

Jack