Corked nose wheel - the return

[Lou]

We discussed this a while ago. The trick would be to test potential solutions in a jurisdiction that permits modifications to wheel pants without approval. I thought Antoine had a friend in Zimbabwe?

To me the problem seems to be the abrupt transition from the rounded front to the flat sides. I think the flow detaches here. I would be interested to see if some small treatment could be used to modify this.

[Rick]

Just a thought - couldn't we figure this out by taping some small orange threads to various points along the front wheel pant, pointing a GoPro or two at the wheel, and then go flying? I don't have a GoPro, but my partner did a few years ago. We noticed the wheel stayed straight through the climb, then moved over as we transitioned from climb to cruise. But we never tried thread to see what the airflow was really doing. It seems like that might be a good place to start...

[Steve]

Probably the easiest solution from a mechanical/installation/adjustment perspective would be a small sheet metal trim tab mounted to the trailing edge of the nose gear fairing. There is already one cap screw located there for securing the two halves of the fairing together, and a second could be mounted easily. I would love to try this, but (un)fortunately, my aircraft doesn't seem to suffer from this issue...

Steve

[Antoine]

Steve
My friend in Zimbabwe used fiberglass over a plywood core - see page 10 of this thread. The fiberglass was laid up over the actual fairing used as a mold. this provided a very snug fit and the screw you mentioned added some positive locking. He said that he gained 5 knots.

[Colin]

If he worked for LoPresti he would have said 7 knots. Those slightly-off numbers sound more real.

[Antoine]

Lol. To be fair it goes like this:

- Starting point is corked nose wheel and trim tab bent to compensate (many aircraft come from the factory like this)
- Remove fairing of the nose wheel and trim tab: gain 1 knot (0.8 to be precise).
- Add back "Zimbabwe" fairing with fish tail: gain another 4 knots.
Total 4.8. Does that sound LoPresti enough Colin?

A post 2007 DA40 that flies with a straight nose wheel should hit 150 KTAS+ between 6000 ft and 10'000 ft on roughly 10 GPH. No excuses: mine has all the antennae you can think of, and even 2 GoPro attachment points and it does it any time I ask.
I do fly a bit slower but that's like 145-147 on 9.x GPH. Good for the engine, good for my wallet!

If your DA40 post 2007 is 5 knots slower you know what the issue is...