We are building a 750SD. We looked into buying a Titan x-370 for it but delivery is at least a year out. The UL 520 delivery is supposedly about 10-12 weeks. Costs are comparable with the UL engines being FADEC and more modern in design. We are at 4600 ft elevation and in the summer regularly get to 7500-8000 ft density altitude. In addition, even going to the next valley means climbing to 11.5 or higher to clear the mountains (Northeastern Utah). The 520T is almost 10G more than the 520iS but the turbo would supposedly give us takeoff power up to 15K feet.

Anyone thinking of installing one of these engines? Pros/Cons?

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I know nothing about the bigger UL engines, bit I have enjoyed the 350i in my Cruzer. It could of course use a little more power… Question, when does UL start their warranty clock, at delivery or when you start flying? You might think about adapting your build schedule and delivery schedule based on the answer to that question.

When you get your SD flying and want to show-off your work let me know. I am nearby in southeast Idaho and would like to see a SD in operation.

Ralph Powell



Thanks for the reply. The UL warranty states:

ULPower Aero Engines, as manufacturer, warrants every ULPower non-certified aircraft engine, sold as new and delivered by an authorised ULPower distributor/reseller, to be free from defects in material and workmanship for a period of 36 months . For aerobatic engines (UL260i(S)a , UL350i(S)a, UL390i(S)a, UL520i(S)a, and the UL520T the warranty period is limited to 12 months. Warranty starts on the date of invoice.

I'll inquire about the 520i(S) or T warranty when used in a non-aerobatic airplane. The other problem with the 520T is it may require 93 aki gas and Utah only has 91 aki gas available. You can use 100LL but get lead deposits on the valves. Could use 70% 91 and 30% 100LL.


Let me be very clear, I have have had only great support from UL. The point about warranty timing is that the warranty clock can run out while the engine sits unused in the box waiting to be installed. If you are a fast builder this may not be an issue. Some us of were slow builders and much of the never needed warranty expired with the engine sitting unused. Schedule engine delivery inline with your build speed.

The octane issue is a pain in the rear. I would consider changing my engine up to 350is specs at rebuild time if 93 octane was not required for the extra power.

Merry Christmas!

Looks like your Christmas wish has been answered by UL Power!


"i" 350 and 520 engines only...not the "iS" versions


Sorry for not replying to you sooner - I don't follow this site very often.  I'm building a 750SD and installing a UL520T and hope to be flying this summer.  I'm installing this engine as I live in the Canadian Rockies and have a mountain outside my door at 10,000 feet.

Ralph is right, for warranty purposes you want to order the engine to coincided with installation.  My installation is one of the first of this type and getting an engine mount that works was a problem but Herman at Wheels and Wings in Florida solved the problem for me.  Herman is a UL Power dealer, is very knowledgable and exceptionally helpful.  He will be sending my motor mount to me over the next week or so.

I'd be happy to talk to you if want to call me at 403 263 0999 - again not really familiar with this forum and not sure I'm suppose to give out phone numbers.



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