Anyone else running this combination?   If so, any noted issues?  Thanks!

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I talked to Robert Helms today about using a Catto propeller on the UL-350is that I ordered today.  He discouraged it because Catto believes that a STOL aircraft should have a LONG two blade propeller.  He said this is hard on the propeller flange.   He thought I would better off with the Sensenich propeller that Zenith currently sells with the firewall forward kit.

He also complained about long lead times and cost.  That's not technically persuasive.  Bending the flange, that is.

Tim, there is more to the story than just the propellor choice for the front of the UL350iS as I may be learning.  As I get more info and hopefully figure things out I will pass along the info.  I think the Catto three bladed (short blades, wooden core hub/blades) I currently have is a very good choice for the performance I want out of the engine/airframe.  I would also opt for a three bladed ground adjustable from WhirlWind or hopefully soon, the adjustable pitch change via pin system that Sensenich has.  I've heard that they are working on configuration for the 350iS, as they already have them for the 6 cylinder UL engine.  Thanks for chiming in on the post....


I ask Airmaster for the current price of a two blade and three blade system.

AP523CTF-SNR70U (two blade Sensenich)  USD9800

AP433CTF-WWR66U (three blade Whirlwind ) USD10550

Looks like Sensenich isn't going to go through the effort of designing and making blades for the 350is compatible with their pin system for blade pitch adjustment.  As a result of hearing that info, along with no known issues reported with the UL350iS and WhirlWind props, I elected to purchase the Whirlwind 3 blade to see how it performs relative to the Catto.  As much as I would prefer the simplicity of changing pitch via the pin system, I found that setting pitch on the WhirlWind was straight forward and not terribly time consuming as I had imagined.  At listed price of $2450, it seemed like a good choice. 

I don't understand your last post.  I have a Sensenich 68" pin adjustable prop on my 350is.

3 bladed ajustable for the UL350iS not available, nor likely (according to Sensenich) - not enough demand to design/manufacture.

OK.  I didn't realize you were discussing a 3 blade.

I just received my GA Whirlwind 3-blade for my CH650/UL350 today.  I've always flown Catto props on my RVs, but his current lead time was a deal breaker.

Mel, I've got about 7 hrs on the WW prop since installing.  So far, I like it on the 750 plus the fact it's adjustable versus the Catto.  BTW, avid follower of your articles in Kitplanes!



I just replied to one of your other posts on the UL engine.  I'm considering the UL520iST for the CH750SD and Airmaster's comments for this engine are:

For the UL520iST I would recommend model AP544CTF-SNR70U


This utilises blade model SNR68U from Sensenich.  They have designed this specifically as a STOL blade for the UL series of engine.

Having 4 blades will help to maintain performance at the higher altitudes.

Budget on USD15k for a complete system.

I've been flying since 1982 and fly a Seneca II but have never had a STOL so I'm way out of my league here (so much so that I'll be getting builder assist) so any comments from you or others would be appreciated on any issues with respect to the plane, engine, avionics, etc. etc.



Which WhirlWind blades are you using? GA-UL350-3B package with 66 inch blades?

Are you able to get anywhere close to 3300 rpm?

I haven't bought a propeller yet.

Tim,  yes, I have that prop package you listed.  With approx 18 1/2 degree of pitch I was able to achieve a static rpm slightly above 2600 pm,  Inflight, level flight, WOT, I saw approx 2950, maybe 3000 RPM.  Will be doing a 50 hr inspection on the prop tomorrow  (got to pull the blades and hubs) and will verify the pitch and RPM numbers again once I get it flying.


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