Cirrus RG?
 

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 :}

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.

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?:}

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...

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.

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

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

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.

RG wasn't needed...
 

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

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?

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.

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.

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.

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.

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.

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:

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.

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.