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On my Soaring Gull , It came with a 2 blade Aerolux prop.Previous owner preferred this prop because 1/4 of his air time was soaring and I suppose 2 blades was less drag.   I switched to the 3 blade scimitar "KOOL" prop. It is smoother and quieter plus  easier to slow down on landings .There are trade offs with every choice .I gave up higher speed for smoothness The engine is the HKS700e  with 3.47 /1 reduction gear. Still messing with pitch to find that sweet spot where I don't exceed 6200 rpm at altitude . However I don't want CHT 's to always be a concern on climb out. Temp ( mid 90's) and density altitude ( 2,000' +) have been against me .   I should wait till Fall however I can't resist the urge to fine tune....   What works for you....This blog has been overly active and I just wanted to squeeze in my 2 cents worth while there was still room.    Carl

I’ll chime in here for 503’ers. Mine has the 3-blade Ivo prop in-flight adjust, and for me that’s the best bang for the buck as you can tune the pitch to suit your needs at the time. In climb I use 6000 to 6200 rpm at full power, and when I push over I increase the pitch and pull the power back to about 5400 and watch the egt’s, which in my humble observation should be monitored with a high quality digital readout like the Grand Rapids EIS. A couple of friends fly with little round needle gauges which is hard to see any minor trends to me.
kb

i'll chime in for the elippse propeller; It did show up in a paid magazine few months ago here; sure is working well in drones for some years now, from a north western state defense equipment firm
R

I agree with Kess. The best part of adjustable pitch is the ability to do high speed descents when you're approaching your destination. Without the adj pitch prop, my EGT's go way too high. So I used to either dive at the destination airport, or do a long descemt at slow cruise speed.

Hi Carl
Set your prop pitch to limit your rpm wile not moving to 5400 rpm!!!!
This will keep your EGT below the redline of 1400 degrees. And give you good climb and good cruse too.
The HKS will not blow up if you go over 1400 f occasionally. In fact you should be running close to 1400 for best efficiency.

503s on the other hand are very sensitive to high EGT.

On the HKS I like 1400 EGT and 5400 cruse on my Odyssey for 90 mph.
The only time I see 6200 rpm is if I am running full throttle strait and level. I just do that for testing.
Happy Flying
Mark
Sent from my iPhone

Were can I buy an elippse prop.
He offered do design one for me but than he died. Now we have lost another great engineer.
Happy Flying
Mark
Sent from my iPhone

Northwest UAV, nwuav.com will make it generally available some year soon. The site ought to be visible in Americana; guess they've added ccTLD based rules to their site content now. based on what I saw few years back, they had refined the design even further to a scimitar shape. it appeared again in the contact! magazine alternative engines site that Patrick Panzera shared a few months, could make out some from the ToC at least ;)

Mark, thou should have just flown over to Paul's home the day he agreed to design one for the Gulls! I was quite taken aback by reading about him passing away too, without reaping the rewards. imagine EAA might connect with them someday and open a shop for them at Oshkosh to sell it for experimentals too or something like that

and today, found this article that talks about yet another prop, a whirlwind scimitar shaped one that looks like worth a test on the Gull too
http://www.eaa81.org/Members_files/Pick ... 20Prop.pdf
http://www.whirlwindpropellers.com/v530/newblades.html

soft landings,
Rahul

wow, the cyclone steam engine mark 5, has a 400 f EGT, external combustion at 1200 f, 125 #, 100HP; only thing is the crankshaft points directly downwards or we could test fly it too; made for boats, cars & tanks
2 cents,
Rahul

how about cattoprops.com, they manufactured thee elippse for Paul, among many other custom props. we could even have a custom prop for the Gull too, based on thine legendary hilift airfoil. (beginning to wonder they also got to retain the elippse design information, Paul's words still live in a sense)

2 cents,
Rahul

Hi Rahul
Thanks, I will contact them.
I had not ordered any props from them for 27 years because there wood, and I dropped wood from my propellor selection because of maintenance and balance problems that don't exist with full composite propellors.
I will call them.
Thanks
Happy Flying
Mark
Sent from my iPhone