Sport Pilot Talk

Anyone see/fly the Renegade Falcon LSA, maybe at Sebring? It looks nice, and I like the idea of the Lycoming fuel injected engine but I’m confused about the stats:

On the spec page of the web site it says 120kt cruise @ 2400 rpm and 4.8 g/h. The plane looks at least as slick as my Sting Sport, so this might be possible, but then I watched one of the videos on the Renegade site and they talk about a 8.4 gph high power cruise(119 kts) and a 7 gph low power cruise.

The plane has a smallish (24gal) tank and I like to land with at least an hour of fuel on board, so the discrepancy (with a safe reserve) is between a 4 hour leg and less than 2, which I consider unusable for cross-country flight.

I’m sure I’m missing something here, thanks for the help.

Could be the difference between true and indicated. The 120 knots are true, indicated is something like 110, at 65% power at 7k or about for the most economical cruise.

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I think it's fair to say that the performance data referenced by most LSA mfgrs has been a combo of 'best case' and vague. E.g. Pete's comment about IAS vs. TAS is a detail that LSA a/c spec sheets often ignore. And to a degree 'best case' is replaced by inflated claims, not real-world numbers. It's quite normal to read that a 100 hp Rotax delivers 4.9 gph @ 75% power (e.g. Zenith) or 5.0 gph (e.g. Lightning) but reports from owners who actually fly at 75% power report fuel burns of +/- 6.5 gph (e.g. Paul's recent trip report to Sebring illustrates this, if memory serves).

Cogito, I think your 'land with an hour of fuel' personal minimum is very common among those of us who fly cross-countries. And an LSA mfgr's claim is not something on which to hang your hat. Personally, I doubt both the 4.8 gph (too low) and 8.4 gph (too high) numbers...but to what rpm are these fuel burn figures tied? (Lycoming allows 2400 and 2800 rpm for 100 and 116 hp ratings). At what altitude? And corrected for standard density at that altitude?

I think what you would like to know is what the FAA mandates Part 23 a/c mfgrs to provide in their POH's: specific fuel burns at specific power settings, corrected for standard conditions, which are validated by approved & reviewed performance testing. The resulting POH graphs allow you to estimate fuel burn for an assumed climb to a givenaltitude, fuel burn at that altitude for the power setting you plan to fly for a duration of your choosing, and a descent burn - IOW a very real-world wind-neutral answer to the question you are asking. Many (most?) LSA mfgrs. provide far less detail of this kind...and it may not be very realistic, either. Fortunately, some LSA mfgrs. do a far more responsible job of this (e.g. Vans Aircraft).

LSA a/c are, by comparison, relatively small. And all by itself, that works against highish speed, long endurance flights.

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Jack
RAF Florida State Liaison
Please visit www.theraf.org

And, very commendable! If everyone had such conservative personal minimums, we'd have far fewer fuel exhaustion accidents. My hat's off to you, Cogito (and, therefore, you are).

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The opinions expressed in this post are those of one CFI, and do not necessarily represent the position of the FAA or its lawyers.
Prof. H. Paul Shuch, Ph.D., CFII, LSRM-A/GL/WS
AvSport of Lock Haven
http://AvSport.org fly@AvSport.org

I don't know how you guys manage to burn 6.5 on a Rotax. When I fly N28GX, it burns 4.0 to 4.1 gph at "Wet Renter Cruise" 5100 rpms. If I throttle it back just a little, it drops down to 3.7 gph, although Michael told me not to do it and run Rotax above 4800 rpms for better longevity (not sure if it makes sense, but he's the owner so I defer). There is no mixture lever though, so maybe some carburators are set to run ROP, some LOP, perhaps? In any case, I expect the Lycoming IO-233 to match Rotax closely. It's fuel injected with ECM for Pete's sake.

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http://zaitcev.mee.nu/

If I cruise my 912ULS at 5500 rpm, I burn right around 6 GPH (depending on altitude). Higher is actually better, because of the self-leaning characteristics of the Bing constant-depression carburetors. I expect the new fuel-injected Rotax will be much better.

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The opinions expressed in this post are those of one CFI, and do not necessarily represent the position of the FAA or its lawyers.
Prof. H. Paul Shuch, Ph.D., CFII, LSRM-A/GL/WS
AvSport of Lock Haven
http://AvSport.org fly@AvSport.org

Ah, that explains some apples to oranges comparison on fuel economy. I would also burn around 6gph at 5500rpm but rarely do so. The extra few knots I gain above 5200rpm doesn't justify the extra 1gph cost for me although there is nothing wrong with it. Heck, at 5500rpm many LSA's exceed 120kts at altitude.

Most folks I know cruise in the 5000-5200 rpm range which is, at most, 5gph so I don't quite agree with Jack:

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dave

I don't understand the 30 min reg. All you need is a little headwind and then a gear-up landing in front of you at your first choice airport and you're in trouble. You should see how conservative my weather minimums are.~

I also like the (seeming) simplicity of the UL Power engines, but would like to see them proven a little. I assume they've got the ASTM nod?

5000 RPM takes just less than 5 gals/hr at just over 100 KTs true for my PiperSport. 5500 takes 6 gph yielding 120 kts at 6500'.

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Dave

So one hour reserve is about 6 gals, or 3 gallons per side. Did it once. Hairs on the back of my neck stood straight out. Did the math about 40 times. Right tank selected and got low fuel warning on downwind to base to final. Don't want to think about landing with less than that.

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Dave

that's why I like how the Sting's wing tanks feed one main tank. No need to try and switch tanks at the last minute. It also hold 8 more gallons than the Renegade Falcon. Doesn't 24 gals. seem stingy?

I assume the reason for the short fuel is the useful load, but as we've been hitting on safety minimums today, I also like having a parachute and that would limit the Renegade's useful load even more.

I'd like to buy a plane like the Falcon, but don't see how one could travel with a friend in one.

Fly shorter legs. I've only ever had full tanks twice, for long solo x-country. When she flies with me I plan on 90 minute legs. Flew that way from Florida to Pennsylvania, and again out to Missouri and back. (Its the journey, not the destination.) At my age, an hour and a half or two hours is about right. If your mission dictates longer legs, you probably don't want LSA.

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Dave

I concur, Dave. I apply the same principle to motorcycle trips. On my recent FL trip, I did one 3.6 hour leg, of necessity. All the others were 1.5 to 2 hours.

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The opinions expressed in this post are those of one CFI, and do not necessarily represent the position of the FAA or its lawyers.
Prof. H. Paul Shuch, Ph.D., CFII, LSRM-A/GL/WS
AvSport of Lock Haven
http://AvSport.org fly@AvSport.org

I'd love to hear more about the Renegade Falcon... impressions of those who have seen, flown, or own it... and/or toured the manufacturing facility. Thx!

Dave, you lost me. There are many of us LSA flyers flying 3-5hr legs. When I transitioned to an LSA I didn't really change the time of my legs although the distance changed (170ktas vs 115ktas). For example, flying to Florida from Dallas next month and I'll plan the 600nm trip with one fuel stop.

You may make a personal choice to take shorter elapsed time legs but this has nothing to do with the aircraft being an LSA.

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dave