I've been requested by several Zenith builders to make this post so builders can ask questions about UL Power Aero Engines and I can respond publicly so other builders gain the benefit of the the exchange.


To start with here is a link to Zenith's webpage showing the Engine and FWF Kit pricing.





Robert Helms

General Managar

UL Power North America, LLC


573 434 0075


Views: 20829

Reply to This

Replies to This Discussion



Thanks Eugene.  

What is your rate of climb with a passenger on board?

Do you measure airspeed in knots per hour?


Speed is in Miles for knots look very slow , kilometer should look even better .

In cool morning two up full petrol we jump to 1000 AGL in 2 minutes easy and speed creep up 70m

Hot afternoon we take it slow for Oil temp jump faster that the 750 , so when it reach 100 Celsius i pull back on throttle to 2800 and i must say we reach 1500 AGL in 5 minutes no sweat .

But i had the Prop on 16 degrees for some time and then it can go up at 45 degree angle all the way but no speed increase , climb out at 55 miles an hour



Thank you


How does the fuel burn compare between the 260iS and Rotax 912iS?  They seem very similar by spec, but Rotax doesn't seem too open to disclosing their numbers.


I'm considering the UL350is to power my Cruzer.  I know it can run on 100LL, but prefers the 93 mogas.  My problem is that I don't have mogas above 91 anywhere near me.  I know from talking with Roger that they use the Decalin fuel additive in the demonstrator to scavenge lead from the 100LL.  Now that the engine has been out a while (and TBO increased to 1500 hrs), what is the recommendation when 93 mogas is not available on a regular basis?  Are there particular brands of additive suggested?  Could a few gallons of 100LL be added per 91 mogas fill-up to achieve an equivalent rating, or is it better just to keep a quantity of Decalin (or similar) around and use 100LL?  What about the VLL or unleaded avgas products coming into play?


Steve, did you chat with Robert about the 100ll issue? 

John, No I didn't.  I saw his post about 2 months later to call if anyone has questions, but I never did.  I've just been monitoring similar discussions in this and other forums. 

I have the same question. I have been using 20% avgas to 80% 91 octane for a HKS 700 and it ran clean as a whistle. I was hoping to do the same with the 350is, changi g oil every 50 hours. Robert said that the engine does not like avgas and that the 350 i would be plenty of hp for the Cruzer. Sure would like the added power for the numerous short turf strips we have around here.

I purchased a CH750 with 350iS, and a Cato prop made for it.  The prop keeps the RPM down around 3,000.  
From my research, talk with UL Power, and basic understanding of how octane ratings are produced, and the anti-knock qualities of them I believe operating 91 or 92 octane should not cause any issues with the engine.  From what I understand it's only at the top end / highest RPM that the octane is of most concern.  For my purposes I purchase, and use 92 in the plane, on a regular basis.  At hi altitude, say above 10,000MSL the engine will spin at higher RPM, as the prop pitch is not enough to keep it down at hi DA.  So I just use the ol' right hand to keep the engine at around 3,100 or below.  Easy so far.  

That is my understanding as well. I will be getting the newly tested Sensenich prop with the FWF kit but I haven't found much info on the test results. Maybe Roger will have them made available soon.

It's hard to keep up with and respond to all the various aviation blogs. If anybody sees a post about UL Power and wants our response please call. Thanks.

Robert Helms
573 434 0075

Hello Robert et al, I have a CH750 with a UL Power 350IS with approx. 250hrs now. I burn 91 octane mogas (no ethanol) for the most part (90% of the time) and very occasionally have used 100LL on some cross country trips. I use the 15W50 shell aero aviation oil. Oil temps have been normal during operation. From the get go the oil turns very dark and I change it every 25 to 30 hrs. Recently checked compression and was good on all cylinders, however noticed the plugs which were changed at 200 hrs. were very black and "sooty". Wondering if this is normal as it appears the engine may be running too "rich". Is there anyway to adjust to make the engine run more lean...or does this have something to do with oil and gas being used?




New from Zenith:

Zenith Planes For Sale 

Classified listing for buying or selling your Zenith building or flying related stuff...

Custom Instrument Panels
for your Zenith

Custom instrument panels are now available directly from Zenith Aircraft Company exclusively for Zenith builders and owners. Pre-cut panel, Dynon and Garmin avionics, and more.

Custom Upholstery Kits for your Zenith Aircraft:

Zenith Vinyl Upholstery Kits

Zenith Apparel from EAA:

Zenair Floats

Flying On Your Own Wings:
A Complete Guide to Understanding Light Airplane Design, by Chris Heintz

Builder & Pilot Supplies:

How to videos from HomebuiltHELP.com

Developed specifically for Zenith builders (by a builder) these videos on DVD are a great help in building your own kit plane by providing practical hands-on construction information. Visit HomebuiltHelp.com for the latest DVD titles.

Aircraft Insurance:


West Coast USA:

Pro Builder Assistance:


Transition training:

Golden Eagle Aviation

Pianosa Flying Farm

Aircraft Spruce & Specialty for all your building and pilot supplies!

© 2023   Created by Zenith.Aero.   Powered by

Badges  |  Report an Issue  |  Terms of Service