What is the correct prop for a Windlass, 503, B-Box?

[V]

I have a 63/34 2-blade P-Prop on my Windlass trike, Aquilla I wing, Rotax 503 DCDI, B-box. While doing a touch and go on our gravel runway and a stray stone took out the one tip and now the question is to repair to replace.

With the old prop the engine develops full 6500 rpm, straight at level at +/- 5300 rpm and I get about 450 ft/min climb, one up. In cruise the EGT shows +/- 610 degrees. I've been told that I should get a more coarse prop to drop the cruise rpm and run the engine a tad cooler. (The engine was rebuilt about 40 hours ago, fan, fanbelt are ok.) However, wouldn't the more coarse prop negatively affect the climb ratio? I know that on in-flight adjustable props the take-off and landing setting is 'fully fine'.

So the question is, what is the correct prop for my setup? Of course, I've sent an email to the ultimate authority, Oom Piet de Necker this morning, but am interested in what the forum says too.

Cheers,

V.

[Wargames]

Hi V,

Contrary to popular belief, a coarser prop is the worst thing you can do. You will lose power on take off and climb, and your fuel consumption will climb as your engine will be 'working' harder all the time. Rather get a prop for max rev at 6600 and lift your carb needle one notch to cool down your egt.

Dont know which prop is best as I don't fly with a p-prop. I am sure oom piet will give you the best advice though.

Regards

[V]

Thanks, Oom Piet says the best for my application is his new 63x35 Aquilla airfoil propeller. The old one is not repairable, have to get a new one in any case. Hmm, the Morningstar tar runway is suddenly looking very attractive.

Cheers,

V.

[Luan]

Hi V,
I have the exact same setup, windlass with a 503 B-Box, Aquilla I wing. When I bought the plane, she had an old 63x34 P-Prop that had been repaired before, she went up to 6660 rpm, after doing touch and goes on a lazy Sunday afternoon my blackberry slipped out and met my prop in mid air, good riddance to the BB, the porp alas was gone. I promptly ordered another from P-Prop, this however was to take a while. In the mean time I was loaned another prop by a very friendly aviator, this was a Geo Kelly 63x32 or 63x33, I can’t remember exactly, this prop made me take off on a dime and rev up to about 6900+, but that was it, I could not get up to altitude even with just 1UP. After fitting the new 63x34 from P-Prop, it felt like a new plane, had a better climb than ever, lower cruise rpm, used less fuel, and only gets up to 6350 rpm. I am very happy with the prop.

[Cee Vee Ess]

Look no further that Piet's new Aquilla 63 x 35. I fitted this shiny new prop last year. Also have 503 B-Box and Aquilla 2 wing. The props new aerofoil is amazing giving you very good fuel efficiency and feels like you have turbo charged your engine. 1 up I climb out at 900 - 1000f/m and 2 up around 450 - 500 f/m. Worth every cent.
My old prop was a 63 x 33 Geo Kelly.

[V]

Hi CVS, was nice chatting to you at Morningstar the other day!

Thanks, the P-Prop Aquilla 63x35 is on and yes, there was a big wow effect: it completely changed the plane. Engine develops 6440 rpm under full throttle and climb, one up, was 850 ft/min compared to 450 ft/min with the old 63x34 (which was also a P-Prop, but a very old design). Cruise is now at 4400rpm. Engine did run hotter (EGT 620 degrees) as Dirk predicted, so I lifted the needle jet a notch. Got late in the day, will see next time what the temps are now.

Cheers,

V.

[Cee Vee Ess]

Hi V,
Glad you impressed. Let us know if you get your EGT sorted out.