Cirrus RG?

[BIRK]

Did a search but no luck. Anyway, i was looking at some pics of a Cirrus, and started to wonder why retractable gear is not an option? I know RG adds alot of (unwanted) MX costs etc. but there are pilots out there willing to pay for the extra kts.

Maybe Cirrus can take some design features from "The Jet" and add an RG option to the SR22 GTS.

plus: Dangling your feet at FL170 and 230kts is a bit strange :}

[tpack]

In case the Airframe Parachute is deployed, apparently, you need the landing gear to absorb the impact. For this reason, I think, Cirrus does not offer RG option.

[poss]

Sounds like a reasonable excuse really. If the parachutes deployed its possible you might not have the available systems to drop the gear so therefore they get rid of that possiblity by offering only fixed.

[deice]

There's that but also the added complexity and weight would offset some of the gains from retracting the gear. A Lancair 400 has similar speeds to the Mooney even though its gear dangles.

Tucking the wheels does add to the beauty (in my mind) and allows more "real-airplane" feel, but at 200 knots who's counting?:}

[BIRK]

is it a requirement from FAA/CAA/EASA to have fixed gear if the airplane has parachutes? I also would prefer landing on three wheels on impact but maybe they could have the gear drop down automatically when the parachute is deployed...

[yawningdog]

I was under the assumption that the Cirrus & Columbia class aircraft went with Fixed Gear due to the rising insurance & maintenance costs of retractables. Their objective was to reduce the speed difference in favour of fixed.

[bjornhall]

Can I have a Cirrus RG if I remove the chute? Don't want the darned thing anyway...

[yawningdog]

Not me, I love the chute. So do my passengers. Just hope I don't have to use it.

[BIRK]

I would rather have a Cirrus RG without parachute. Since I started my PPL lessons I have flown aircraft without parachutes and feel quite safe. I have always had my doubts about the parachute system, it gives you false sense of security.

[Tim_CPL]

I read an article some time ago about the design of the SR2x series. The main reason was crazy insurance issues with retract, the ethos was just to put a bigger donkey in the plane to overcome the small difference that the retract gave. An additional reason cited was the fact that the gear is an integral part of the crash certification (recall the SR that splashed down on a river with the chute deployed and the pilot still broke his back).

- Tim

[jumpuFOKKERjump]

I understand the parachute is not just there as a safety gimmick, it is required for certification. Most even reasonably modern aircraft probably couldn't pass the obscenely restrictive spin demonstration requirements of FAR23, the parachute can do it so the aircraft flies.

I understand the requirement is to recover from a spin 10% over max gross weight, c of g 10% past the aft limit. That's why the tail on a GA8 looks like it came off a Caribou.

Why do you give a sh1t whether is has a parachute or not? Due you stagger, crying, from dealer to dealer looking for cars without airbags or seatbelts?

[IO540]

I was under the assumption that the Cirrus & Columbia class aircraft went with Fixed Gear due to the rising insurance & maintenance costs of retractables

Unfortunately this turned out to be a marketing myth.

Ask a U.S. Cirrus owner how much he pays for insurance.

Ask a U.S. TB20 owner (of similar hours etc) how much he pays for insurance.

Cirrus have done a cynical marketing exercise where they are selling "simplicity" (as if retractable gear was complex :ugh: to own or operate) but the owner pays for extra fuel all the way. We don't know how much this is (because there is not a RG Cirrus) but I would estimate around 10% of fuel is wasted, at cruise speed.

[172driver]

My understanding was /is that they didn't go RG because of the certification costs (both in money as well as time-to-market terms). Designing an aerodynamically efficient a/c with a big engine seems to have done the trick. OTOH, though, to my knowledge you cannot certify a fixed gear piston for FIKI, at least there doesn't seem to be one out there. So, from a IFR touring POV, there should be a case for an RG variant.

[gasax]

If you properly fair a fixed undercarriage it has a pretty low drag. compared with the additional weight from the structure, machinery and systems for a modern retract it saves significantly in terms of weight and cost.

Given it has a parachute it also offers a significant near guaranteed energy absorbsion on its final descent - getting that sort of energy absorbsion any otehr way would probably be impossible.

Look at a number of the older Cesspits and see just how little performance is gained from un-faired undercarriages compared to the equivalent retract - at under 200 knots its a wate of time lifting the legs.

[poss]

As said above the gear, it would seem, was designed to provide shock absorption, probably the reason the guy that went into the sea broke his back as the gear wasn't able to do it's job. This would mean that to add RG to it, if the RG didn't drop and the engine stopped Cirrus owners would have large odds of damaging their backs if they deployed the parachute. Perhaps it's a secret safety feature and Cirrus are trying to throw off the competition.

[IO540]

If you properly fair a fixed undercarriage it has a pretty low drag. compared with the additional weight from the structure, machinery and systems for a modern retract it saves significantly in terms of weight and cost.

I don't think so. Referring to a PA28-161 POH I saw a while ago, the Piper cowlings on what were worth about 7kt on top of 100kt - that is 7% which is probably about 15% engine power lost. And this is at the very low speed of ~ 100kt.

I don't think a 10% loss on a much more slippery 150kt plane is an unreasonable estimate. It could be more.

Cost? There I agree.

Weight? There is some extra weight (offset by not having to carry the fairly substantial weight of fibreglass fairings and associated fixing hardware for these) but the fuel penalty in carrying say extra 30kg (actuators, hydraulic pump, etc) is very small. FAR less than losing 10%+ of engine power.

[deice]

IO540, you're saying the Cirrus' use unnecessary fuel? Tell me, how huch does your TB use at a typical Cirrus cruise speed of 150 kts at 2000 feet? Most, if not all 200 hp 4 seat singles cruise in the 125-140 knot range at similar power settings where the Cirrus does 150. And, it does so with its feet dangling!

Did you know the Rutan Quickie has the same drag (complete aircraft) as the landing gear of a Cherokee? Food for thought...

Spent part of today speeding around in a DA40D (holding my breath) at 130+ knots with only 135 hp, and that's at 1200 feet (100% power for a minute or so). Amazing aerodynamics with gear down and welded. :ok:

[IO540]

IO540, you're saying the Cirrus' use unnecessary fuel? Tell me, how huch does your TB use at a typical Cirrus cruise speed of 150 kts at 2000 feet? Most, if not all 200 hp 4 seat singles cruise in the 125-140 knot range at similar power settings where the Cirrus does 150. And, it does so with its feet dangling!

That's not actually true, once you look at real figures, LOP v. LOP and not looking at sales brochure figures.

My TB20 does 139kt IAS (low level say) at 11GPH. This speed is almost exactly (within 1kt or so) what an SR22 does at 11GPH.

That is why I am very sure that an SR22 does indeed waste a lot in the fixed gear. The alternative is that its very nice looking airframe is not significantly more slippery than a TB20 airframe; that is frankly also a possibility because we are not talking about supersonic speeds...

TAS for TAS they are the same too of course, about 155kt at 10,000ft at 11GPH.

The difference between an SR22 and a TB20 is that the SR22 has a bigger engine, so if you run both at say 65% the SR22 will be faster. But at a higher fuel flow.

Finally, beware the TAS comparisons in sales brochures because they are often at different altitudes.

Of course the turbo SR22 will beat a TB20 on MPG at say FL170, quite significantly. As will a TB21 (turbo also). But that's a different argument.

[yawningdog]

SR20 that I fly will give 132kts+ (IAS) at 75% power with 10.5gph, all temps within limits.

[IO540]

SR20 that I fly will give 132kts+ (IAS) at 75% power with 10.5gph, all temps within limits.

That's same (the SR20 maybe a few kt slower) as a TB20 would give at 10.5GPH. That supports my SR22 point too.

In a way, all this proves there has not been any drastic innovation in this field since WW2.

[IanSeager]

In a way, all this proves there has not been any drastic innovation in this field since WW2.


Those pesky laws of physics again...The SRX series does seem to offer more room internally than the TB20.

Ian

[deice]

The figures for the SR20 sound really low. The one I flew (admittedly a little) was indicating 150 kts at 75%, but I'm not arguing your numbers, just surprised. I don't go by sales brochures, I make them for a living - I know they lie, just like I do... :}

The Commander I used to fly would do 145 kts @ 6000 feet and 12 GPH which is higher than book fuel flow, and slightly less efficient than the TB as I'd expect.
I'm surprised the SR isn' better in fact. However, what you're saying is that speeds and fuel flow match but that's with gear down on the SR and reracted in the TB I presume. How does the TB perform with it's legs down? The Commander basically stops in its tracks when they're lowered!

[IO540]

I'm surprised the SR isn' better in fact. However, what you're saying is that speeds and fuel flow match but that's with gear down on the SR and reracted in the TB I presume. How does the TB perform with it's legs down? The Commander basically stops in its tracks when they're lowered!

Well it just proves that whatever the SR picks up with a better body it then throws away on the dangly legs. This is of course totally contrary to what Cirrus salesmen tell you; they claim their fixed gear loses 2-3kt - this is complete total b00011ocks. Well, it may be true at 70kt :)

The TB20 drops from 140 to about 125kt when the legs come down. That's a LOT of horsepower!

TBH if I didn't have the dangly legs I would like a speed brake. The legs come in very handy at times. The only problem is that while a speed brake can usually be activated anywhere below Vne, I have to be below 130kt to lower the gear. A landing gear that can be lowered at Vne would be a great advantage.

[scooter boy]

What you need to do is look at comparative performance for all piston types.
The long-body Mooney wins hands down in terms of speed, fuel efficiency and range every time.
Having the gear hanging down significantly degrades performance at all speeds - period.

I love the feel of the acceleration I get when the Mooney gear tucks away into the wing - sweet!

Plus it is FIKI deiced and has the fully integrated G1000 (now with GFC 700 autopilot) as standard.

Problem is Mooney advertise only about 5% as much as Cirrus and their lean ad budget is matched by the limited column inches their aircraft receive in coverage.

If somebody farts at Cirrus it is headline news in Pilot/Flyer etc...

But if people want to fly the equivalent of a Ford Mondeo...


SB

[yawningdog]

The one I flew (admittedly a little) was indicating 150 kts at 75%

The SR20 that I've been flying is a 2003 version. I've never managed to achieve anything like that except possibly in a descent. I have to say that the Cirrus makes up for everything by the ease and way that it flies. Its a joy.

http://www.yawningdog.co.uk/stuff/P1070713a_1404x882.jpg

[deice]

You're indicating 130 at 7000 and 4 degrees. What's that in TAS, 140? Is that at 75%? Not too shabby and far better than an Arrow, 177RG or 172RG I'd think. The Cirrus looks pretty efficient to me.

[deice]

I think the Mooneys are terrific except they require acrobatic maneuvers to enter, end exit - one thing I don't like about aircraft with just one small door. The 201 is my favorite as it provides unrivalled speed and economy, for an avgas burner, but again, who wants to fly in a tiny tube? Personally I look forward to the 170hp DA40, I'm pretty sure it'll be a blast.

[bjornhall]

Fuel burn figures, airspeed figures, insurance costs, maintenance costs ... *yawn* :zzz:

Let's focus on what matters: Retractible is way cooler than fixed gear.

End of discussion. :ok:

[yawningdog]

Is that at 75%?

Yes. I calculate TAS as 145kts, but that's by using an online calculator.

[scooter boy]

"Retractable is way cooler than fixed gear":ok::ok::ok:

Absolutely Bjornhall, the birds dig RG, both feathered (who I have noticed never fly with their legs dangling down) and also it is rumoured the non-feathered variety.

Deice: I have no problem with the single door entry for the Mooney - it means fewer doors to open during flight and less to check before takeoff.
The large baggage door at the back of the cabin is easily big enough for an emergency exit and is openable from the inside. So if an unconscious Roseanne Barr is blocking your egress from the aircraft and you can't uncork her (even by throwing pies out onto the wing) you can find another way out and help pull her out.

Fewer breaches in the structure = better structural rigidity, ask and ferrari or porsche owner why the performance car purists usually drive hard tops and soft top versions are the territory of the poseur/hairdresser.

SB (Fully retractable fully enclosing gear with shiny doors and rumoured to be dug by at least 2 (non-feathered variety) chicks from Maders)

[IO540]

There is no doubt that there would be a lot more birds hanging around the GA scene if there were a lot more flashy planes around. A TB20 (one in good nick) certainly draws the appropriate attention :)

I do think single door planes are a bit of an acquired taste though. After 6 years of the TB20, I would never go back to a single door design. 2 doors are so much nicer for me, the passengers, and general usability. As just a little example, much of the time it is windy and cold at the airport and I can get any passengers inside the plane where its' nice and warm while I do the preflight outside, and I can then get in without anybody having to get out.

Obviously the bigger hulls like the Meridian are easier but they have the large back door entry anyway, with steps.

[deice]

SB - Even a Ferrari has TWO doors and I haven't seen many ragtop aircraft lately, have you? Come on, you're calling the mail slot in the back a door!?
I don't often fly around with Roseanne but I'll let her know you suggested pies on the wing... :}

The TB may be an attractive bird for the likes of us - flying nerds - but I have yet to come across a "bird" that was excited by the looks of a particular aircraft. Most seem uninterested except about the flying itself. In terms of sex appeal I think modern composites are more likely to win points even among the blokes.

Had a trial lesson just yesterday, our shiny DA40D parked next to a geriatric PA28 with a flat tyre. It's just too easy to win them over, even with a "shiny" tin can right next to the DA, the difference is just too obvious, and I dare say it's in favor of the fast glass.

Ok, so a Mooney may look cool, and the TB20, but if we're talking "regular" tourers and trainers there's no contest.

[FL1]

Hi all

I've been flying the Cirrus SR22 all over Europe for a small group of private non pilot owners, and wanted to know if there are other owners or pilot owners of SR22 who require a pilot or safety pilot.

[skyfiend]

I've never understood this "can't be doing with one door to get in and out" argument.

It's a bit like saying that I fancy a sports car but won't have a Caterham as you have to take the wheel off to get in and then put harnesses on...

So what? It takes 3 - 5 mins and then you are wearing a pure performance thoroughbred. I can't understand why anyone would chose a flying machine based upon criteria about getting in and out of it on the ground. Seems such a minimal part of the whole flying and ownership experience.

But what do I know - I fly a Pitts...

[MCR01]

Dyn'Aero MCR01 VLA does 140+ knots at max. gross weight at 2000feet on 80 (yes eighty) HP and with fixed gear - course it's only got 2 small seats (and currently thanks to the PFA/LAA all UK examples have been grounded since Xmas). Roll on EASA.

[Rod1]

“and currently thanks to the PFA/LAA all UK examples have been grounded since Xmas”

Really, news to me, I have been flying for weeks. I take it you are one of the 7 poor soles who have a mk1 tail?

Rod1