UL 520T Comparison

[Nev]

Paul O'Donnell mentioned in another thread that he was planning to install a UL Power 520 - something that got me thinking a lot more about it, so I did a spreadsheet (of course I did !) comparing several of the more common engine installations. It's by no means definitive, and uses my best weight estimates based on already known actual aircraft weights, published engine weights, and published HP/density altitude charts. I've added a column to illustrate Power/Weight ratio (actually Weight/Power but you get the idea). The lower that number, the better the expected performance.

I've compared the UL520T (Turbo) to these engines because I was really interested to see the effect of a modern engine, turbo normalised (maintains sea level manifold pressure to 15,000ft), single level engine control. The one main issue would be CG.

The UL520T is approximately 180 LBS lighter than a typical IO540, so if the CG issue is resolved it will provide very similar Power/Weight at low altitude, and once above about 3000ft density altitude it starts to exceed that performance in every way. I didn't calculate cruise speeds, but with a surplus HP and better Power/Weight at all altitudes above 3000 ft, the cruise speeds (both IAS and TAS) should be significantly better. Landing performance improves due to the lower total aircraft weights when compared for the same payload due to a lower approach speed (and hence less of those pesky V² 's) and shorter landing roll.

The chart below compares various engine installations at a Take-off Weight (TOW) of empty weight + 640 LBS.

IMG_2467.jpg

[U2fletch]

The published numbers I've seen and researched suggested a weight savings over typical sized Lycoming or Continental of approximately 40lbs. An extended engine mount of a few inches is supposedly available to remedy that. At least that's what the UL Power guys said when I spoke to them at Oshkosh last summer. I was just up at Smiley Creek, ID with a group of 30 Glastar/Sportsman owners and 2 of them have the UL520T in their planes.

[paulodonnell]

Hi Nev

That's very interesting - given mines going into a Patrol, I'll ignore the two columns relating to the 540 & 390 ..but the results look like its going to be a very impressive climber that's going to use a lot less fuel. In Ireland Avgas is 2.70 euro a litre vs Mogas at 1.70 . The UL is happy to sip either one of those. It will be very interesting to see what the cruise speed will be.

Another thing swaying me, it seems less complex in operation of course but even in installation...for instance a headache I had was how to do the throttle in the opening S.P. port door - I'd seen guys use rose joints etc and warning placards 'no throttle with door open'. With the Ul I've got door mounted twin throttles pulling a sheathed cable, AKA a motorcycle I'll leave a little slack so the opening door has no effect just like turning the bars on the bike. Perhaps I'm being over optimistic here because I will have to fit an intercooler etc but plumbing and welding were my trade once upon a time.

C of G (according to Bob in conversation the other day) seems not to be a problem in the smaller aircraft, he described it as a 'good fit' . Bob said the Patrol was designed for 320 to 360 motors. The small legacy motor with a wooden prop would weigh a little less, and with the IO-360 a little more. I'm going to be using a Kiwi Airmaster 4 blade reversing prop (for my future seaplane aspirations) that's 40lbs so with the proposed set up he said prop flange is still a the stock 56 -58" from datum. Given I also will need their twin electric fuel pumps and filters (which have just arrived) and a fuel swirl pot or header tank the will be fitted in the cargo area I'll be keeping to the 58" - UL in Belgium are incredibly helpful and will construct and certify and do any further mathematics on the engine mount too.

Radek in Poland has recently started flying a lovely BH4 fitted with the UL520T, I don't think we see Radek on here perhaps for language problems , but his aircraft is really beautiful in silver Oratex.

image7.jpg

[svyolo]

Can that engine use a hydrailic prop, or only electric?

[paulodonnell]

No hydraulic prop, the one on the pic above in Poland is an MTV electric - I'm using an Airmaster as I'm getting a reversing unit.