I’ve sat behind (L)TIO-540-Js for a few years now. Lycoming’s TBO its notionally 1800hrs; I’ve seen everything from 950 to1500.
A 100kW air conditioner or a zero-CV properly designed radiator. Unfortunately the science and research behind proper radiators has been lost in favor of “air flows in through here and out through here”, which is a pity considering the intricate radiator designs one could build with a 3D printer.
I just tried flying the Belgium Sonaca 200 demonstrator this morning. I realized this is the first time I have ever flown a fixed-pitch prop with a turbo-charged engine, the Rotax 914. I flew with the company’s chief company designer and I asked him about the choice of a turbo-charged engine, as this aircraft is made for training, and other design choices tended towards economy (the fixed prop, round-dial flight instruments). Apart from the fact that Rotax do not have a 115 HP naturally aspirated engine, the answer was that the downsides were considered few, and expected maintenance costs and overhaul times were not considered significantly worse.
I think it is a very nice aircraft.
Peter wrote:
However for some reason not everybody gets the better MPG. A TB20 seems to have some 20% more range than a TB21. We have done this one before but I am not sure it was ever settled why. I think it must be because most of the TB21 owners fly ROP to keep it below the TIT limit, and that is a ~20% hit on the range straight away.
To compare the POH of TB20 vs TB21 at same power settings at their typical cruise levels:
TB20: FL105@65% = 153 KTAS / 47,9 Ltr/H
TB21: FL210@65% = 166 KTAS /47 Ltr/H
Or for the approx same level and same power setting:
TB21: FL110@65% = 155 KTAS /47 Ltr/H
The POH is generally accurate as I see it. Its true you have to enrich a little over the book values to keep the temps low if you want to be nice on the engine but that’s mostly high above FL100 where you also benefit from the increased speed. So I don’t see how this can ever translate into a 20% worse range.
europaxs21-Sep-17 05:50 #83
EuroFlyer wrote:
Over here in Europe, you can do without…
What??? Think of all the 600 m grassfields? You’d miss out >50%.
Hm.. I’ve never had any problem whatsoever with 600m grass. And the turbo isn’t a factor under 6500ft. So what’s the point ?
With the SR22 there is very little difference up to 10.000 feet … the NA climbs better up to 8000 with the same payload due to lower weight. No difference in t.o. performance at typical elevation.
Very interesting article on turbo intercoolers in today’s AVweb article:https://www.avweb.com/news/features/Intercoolers-Turbo-Enhancement-229657-1.html
@EuroFlyer – my point (at least): see post 87 
europaxs wrote:
Peter wrote:
Well, a C172 will be doing 200fpm at 10k; sure
No
JasonC wrote:
All of your internal combustion engines are on the brink of failure as far as I am concerned :)
Ha Ha Jason, I do believe that apart from a small number of rocket propelled flying machines they are ALL internal Combustion engines!
