Spat problems

[Guest Andys@coffs]

Hi Guys

 

Yesterday on returning to Gawler I had a most exciting landing. The passenger side main spat mounting bracket being the extruded aluminium U tube that goes on the inside of the main undercarriage leg, had completely fractured along one of the fold lines (Yeah, I know its extruded not folded...but you know what I mean) . this allowed the spat to rotate on landing, which it did to the point of creating a complete wheel lock up on that side.

 

Fortunately for me the circuit was busy and unlike normal I had determined that as soon as I landed I wanted brakes on fast so that I could immediately turn off the main runway at the cross strip intersection, whereas normally I would land, run past the intersection and backtrack. Had I not had the brakes on hard the asymmetrical braking effect wold have been much larger than it ended up being and I could have ended up with much more damage than I did.

 

Total repair bill at this stage will be a replacement of the brake line (pinched by the rotating spat), replacement of the tyre on that side, which now has a serious flat spot on it. repairs to the front of the spat and the U tube.

 

Of course I will also drop the other side spat and determine if that U tube is also cracking.

 

So guys, if your spat mounting methodology uses the U tube mechanism (and from the construction CD it seems that there are a number of different ways that the spat is mounted, depending on whether you have single brake callipers or dual) then best you have a look at the tube for integrity

 

I'll be sending a copy of this to techman for his info, and will photograph the issue and post latter today if possible

 

Andy

 

 

[Guest Andys@coffs]

The photo below shows the photo out of the construction manual. Ive included just so as you know what metal Im talking about.

 

[ATTACH]3377.vB[/ATTACH]

 

 

 

[BigPete]

Hey Andy - :)

 

my Jabiru has the U upside down and fitted to the top bolts - makes a good jack point. ;)

 

regards

 

 

[Guest Andys@coffs]

Pete

 

Mine too are upside down and fitted to the (top -wrong) bottom bolts. That'll show when I photograph them. Not today though, yardwork called...

 

P.S if their aluminium like mine I'd suggest that in fact they dont make a good jack point at all, stres from jacking might initiate the crack I talked about

 

Andy

 

 

[BigPete]

Mate I recon your right ;)

 

- another job on the list - replace with stainless steel. ;)

 

regards

 

PS I leave my spats off - grass strips.:big_grin:

 

 

[Guest J430]

Hmmmm......

 

I have had the exact same spat failure, minus the damage, just notived a wobbly spat and investigated. The vibration from some rough strips like the one I operate from is most likely to blame.

 

Now here is the funny part, I removed them both, and the thing flew faster!!! Yes I know this defies the normal thoughts of folk, however I think they created more drag than they reduced. Another J at my field a J200 has none and they are a speedy unit (Turtle care to comment?).

 

As for going to S/S, I would think a more ductile material that will not work harden if you replace the existing one.

 

J

 

 

[Guest grantisaac]

We leave our spats off. Have you reported it to the RAA? Could save someone else from a costly repair bill

 

 

[Guest Andys@coffs]

Yep, the report to RAA was the reference to "techman" above. I sent Chris an email earlier today referencing this thread.

 

Andy

 

 

[Guest grantisaac]

Sounds like you are lucky that you did not do more damage or hurt yourself.Hope the hurt to your pocket is not that bad.

 

 

[TechMan]

Thanks for the info Andy. Have taken it up with Jabiru for the moment to see if they have any alternatives available.

 

Chris

 

 

[Guest Andys@coffs]

Hmmmm......Now here is the funny part, I removed them both, and the thing flew faster!!! Yes I know this defies the normal thoughts of folk, however I think they created more drag than they reduced. Another J at my field a J200 has none and they are a speedy unit (Turtle care to comment?).J

Well I removed both the main spats (only the passenger side C channel had cracked) and I can confirm that the spats had no noticeable positive effect on the aircraft speed. In fact I too think that the Aircraft is slightly faster with them removed.

 

Bottom line.... I'm over spats, they can collect dust in the corner of the hangar for the moment. Nose wheel spat comes off this coming weekend.

 

Andy

 

 

[Guest JRMobile]

Now here is the funny part, I removed them both, and the thing flew faster!!! Yes I know this defies the normal thoughts of folk, however I think they created more drag than they reduced.

We have been flying spatless for some time and would agree wih the above.

 

 

[Guest brentc]

I've done everything I can to keep mine on! I'm on my third set. I found that my aircraft went faster when I fitted them. Interesting.

 

 

[Guest osprey5]

They do look better with the spats on but if performance isn't an issue, then I think we'll take our's off too as they make checking the tyre pressure a major task.

 

 

[Guest Andys@coffs]

Today I arrived home after a trip Gawler-Narromine-South Grafton, returning a week latter.

 

On a long trip, wind effects mathematically excluded, its quite clear cut that the spats do improve the cruising speed on my aircraft. As such, they'll be fixed and refitted.

 

While testing (before the trip) I flew the AIrcraft without main spats and then without nose spat. I think the nose spat had more impact than the mains.

 

Andy

 

 

[Alan]

Had to remove my main wheel spats for some minor repairs and also found a 3 to 4 knot cruise speed reduction without them. Could the variation in effectiveness of the spats from plane to plane be a function of how true they sit with regards to airflow when in place?

 

Alan

 

 

[Guest J430]

Must be the only answer I have come up with. TAS of 120kts without them at 23LPH. 2900 RPM.

 

Hard to tell really! Other I know of say they make no difference.

 

J

 

 

[Guest AVU]

Hi Gang.

 

Just an observation on my part, that spats fitted to an A/C irrespective of type, are there to reduce parasitic drag if fitted correctly, but it makes it harder to check tyre pressures by having to rotate the wheel to get the valve stem in the right position In the training environment it is easier to leave spats in the hangar at the cost of a few kts in airspeed, not to mention the buildup of unwanted materials inside the spats (like redback spiders if the A/C has been standing for a few day's) when landing in some less than ideal places. They certainly serve a purpose in reducing drag and cosmetically look the part. But they must also figure in the routine inspection. Manufacters recommendations? Still, if they serve the purpose, and are of practical use, go for it.

 

Cheers.

 

Steve

 

 

[Alan]

Spat/streamlining design changes

 

I had one of the streamlining panels of my main undercarriage legs come off in flight (another good reason to not fly over towns!). It seems the forward screws had come out and it cantilivered back breaking off. In the attached photo it is just the outboard panel marked in yellow that went missing (while we were under there we also removed the main cross fairing to re-check the UC bolts;) ).

 

The difficult point is that the Aircraft is only just over a year old and Jabiru no longer make that style of streamlining and cannot supply a replacement panel; a set of the new style covers is circa $250 not too bad I suppose, but it will involve drilling a new set of mounting holes - not nice.:yuk:

 

Thankfully, it is a relatively simple panel and I will make up a replacement:sad:. Now what ever happened to that spare time, I had hidden.

 

Have now rechecked the rest streamlining fairing fixing screws on my Jab and several were not firm. They are now loctited in place.

 

Make sure your fairings are tight or you may end up like me - covered in styro foam dust and sticky with epoxy or worse drilling some extra holes.

 

NB. The two piece front wheel spat is no longer available either. It is now one piece. I cracked the front part of the fairing - don't ask:sad:. Even with prompting (telephone & email) Jabiru took so long getting back to me to tell me it was not available, it had been repaired and refitted.

 

Maybe all the speed variations reported with and without spats are also influenced by which variety of spats are fitted.

 

Alan

 

 

 

[Guest brentc]

That's a co-incidence. I lost two of those 3 years ago somewhere between Jamestown and Goolwa in South Australia on the same flight. I got some replacements and put another half a dozen screws in to hold them on better, plus some 100mph tape to be sure. They don't hold up to the undercarriage movement very well. I note that these fairings have all changed now to something much more basic.

 

 

[Ross]

Hi Alan

 

I note that your "nuts" that are used between fairings look like the push on type that were commonly used on some car panels years ago together with self tappers.

 

I ordered an extra supply of retained nuts from Jabiru (the type that require two rivets to secure them) and are mated with a machined SS screw either CSK, Pan head or hexagon head as required.

 

My bottom cowl uses CSK stainless screws with the retained nuts. The instrument panel uses on my #14 J160 kit pan head screws with retained nuts. The locking tabs for all the control hinges use pan head screws with the retained nut (held by two pop rivets).

 

I have used them to secure items like fairings to fairings around the UC legs and struts & the strut fairing to fairing on the wing connection and the extension to the centre console between the pilot & passenger.

 

I still used the self tappers to connect removable fairings to the fuselage.

 

There is far less chance of these screws with retained nuts falling out, getting loose or the hole enlarging when compared to using the self tapping screws.

 

Regards

 

 

[Guest J430]

We used the retained nuts etc....550 hours no fairing problems.

 

J

 

 

[Alan]

Yup going over to retained nuts and race tape seems the way to go. However, being a factory 230c built to LSA regs, is an allowed mod? Seems counter intuitive not to allow this type of work, but I will check.

 

Alan

 

 

[Ross]

Another way out of the problem might be to put a little dab of opoxy mixed with flock in the second hole of each location where a self tapping type screw is used and then insert the self tapper.

 

If you are unable to extract them later with a Philips head screwdriver I find that a pair of Fencing pliars specifically designed to handle high tensile wire will allow you to grip them hard enough to rotate them for extraction.

 

[ATTACH]4564.vB[/ATTACH][ATTACH]4565.vB[/ATTACH]

 

The jaws in these pliars are hardened steel and unlike most pliars stay parallel as they are opened or closed. They will also cut spring steel without damage to the cutting edge.

 

Regards

 

 

 

 

[jcamp]

Had problems with getting the phillips screws in the spats out and then back in tight enough. Solved that by using hex socket head screws. They don't appear to be available in Aus or anywhere at 100 degree but Fastener Express in the US has 8x32 Flat Head Socket Cap stainless screws available in 82 degrees.