Retracts vs Fixed gear

[brian]]

To those that say- "With new modern, digital designed fixed gear and modern materials, there is no reason for retrac anymore...", I say, what if a company were to apply the same 21st Century design and materials to retractable designs? To my knowledge, no planes available to buy have ever done this yet. Even kit planes offer the same ol' stuff from 1960. IMO, retractable designs could be made much, much lighter than is currently available and therefore reduce the induced drag and lower gross weight associated with retractable gear.

Bottom line is, if one is designing an airplane to be the fastest, or most efficient it needs retractable gear. If the goal is to land on sand bars in Idaho, or be the cheapest and easiest to build, then probably fixed gear is the way to go.

Ok, it is a twin, but the DA42 was able to drop in two weak diesel engines, composite (fiberglass?) construction, and retrac. The result was about 172KTS and the ability to climb on the one anemic diesel engine. Oh, and the fuel burn was less than many singles at the same speed (something like 7GPH per side in cruise).

(Of course they have since added some real HP and since they are out of my pocket spending money, I haven't kept up.)

Anyway, you wanna go faster, gear comes up. But I still get the Cirrus mentality - good design.



Oh, and the swift - that was a delightful pic!!

 

[flyingron]

There's videos of people landing gear up with the horn blaring away. My instructor was teaching someone in a Bonanza and after flying most of the pattern with the horn going, he suggested to the student that if he increased the throttle a bit that noise would stop. Alas, the student did.

This was the guy who drilled into my head on my retract training to check for three green on every short final. Worked well for me on my engine out when I was busy getting it back to the runway and everything else and as I'm finally going to make it I say "three green? NOPE". Fortunately it comes down fast in the Navion.

 

[Dav8or]

But what about the horn, did they just ignore it or was it broken?

The horn helps a bit, but it is blocked out of consciousness all the time by distracted pilots. Electric gear Mooneys now make up the majority of the fleet and they all have gear horns. These planes are landed gear up regularly just like every other brand of retractable planes. Most recently at my home field, a King Air.

Serious distraction in the pattern is what causes gear ups. Nobody ever gear ups a normal, relaxed landing.

 

[MooneyDriver78]

The horn helps a bit, but it is blocked out of consciousness all the time by distracted pilots. Electric gear Mooneys now make up the majority of the fleet and they all have gear horns. These planes are landed gear up regularly just like every other brand of retractable planes. Most recently at my home field, a King Air.

Serious distraction in the pattern is what causes gear ups. Nobody ever gear ups a normal, relaxed landing.

There is video of French pilots landing with gear up despite horn going off, with 2 pilots,what seems like a normal landing. I had my gear horn fail and unfortunately it's not something you can preflight, so maybe it's a common failure, or poor annuals that don't check.
I be interested in hearing from anybody who has landed gear up if they just blocked out the horn or if it was broken.

 

[txflyer]

Meyers 200D has one of the cleanest drag coefficient gear up profiles in aviation.

That's why they're so danged fast ...

 

[RudyP]

I have an SR22TN which is a 220KTAS fixed gear single and I'd magically make it a retract if it could give me an extra 20+ knots of cruise speed and didn't cost any $. Any less of a speed increase and it would not be worth it to me though, particularly with the increased risk of landing gear up.

I bet that with modern systems, if Cirrus were to build a retractable version of the SR22, it wouldn't just have a gear horn but it would actually announce "Gear up, Gear up" and as you got closer and closer "Gear up, go around!" or something like that. The plane talks to me constantly about altitude, sink rate, traffic, etc... So I think it could easily be programmed to have a 'smart' gear warning that is much harder to mentally tune out than a gear horn. Not saying that someone wouldn't figure out how to land it gear up anyway, but I think they'd have to try a bit harder...

Maybe we'll see how this goes with the SF50 because there is no way Cirrus is going to be building a retract SR series airplane.

 

[hindsight2020]

I have an SR22TN which is a 220KTAS fixed gear single and I'd magically make it a retract if it could give me an extra 20+ knots of cruise speed and didn't cost any $. Any less of a speed increase and it would not be worth it to me though, particularly with the increased risk of landing gear up.

I bet that with modern systems, if Cirrus were to build a retractable version of the SR22, it wouldn't just have a gear horn but it would actually announce "Gear up, Gear up" and as you got closer and closer "Gear up, go around!" or something like that. The plane talks to me constantly about altitude, sink rate, traffic, etc... So I think it could easily be programmed to have a 'smart' gear warning that is much harder to mentally tune out than a gear horn. Not saying that someone wouldn't figure out how to land it gear up anyway, but I think they'd have to try a bit harder...

Maybe we'll see how this goes with the SF50 because there is no way Cirrus is going to be building a retract SR series airplane.

Or do like Piper did way back in the last century and drop the gear for you below a certain pitot pressure (airspeed) and throttle position. It's not cosmic really.

 

[docmirror]

I have an SR22TN which is a 220KTAS fixed gear single and I'd magically make it a retract if it could give me an extra 20+ knots of cruise speed and didn't cost any $. Any less of a speed increase and it would not be worth it to me though, particularly with the increased risk of landing gear up.

Given the coef of drag, it might be right around 20kts increase, but there's a lot of assumption in my post. I really don't know the gear on the Cirrus except that it is very slippery. A retract would need to be fully flush, and doored well to improve enough, and that's a lot of moving parts. I think the retract design of the Bonanza is elegant and just about the best in the GA biz. Would be interesting to engineer that. I know the designers did a fair amount of testing on retract for the Cirrus, and they must have found out that the benefit wasn't worth the cost in machining and maybe more-so in liability. One of the primary goals of the Cirrus was safety, and having the gear tucked in was a safety issue, although very few gear mistakes lead to injury or fatality, just bent metal(plastic).

 

[Henning]

Remember that the gear is an integral part of the CAPS system on the SR-22 as well. I have a feeling that complication was the primary reason to discard retract gear.

 

[RudyP]

Good point Henning.

Will be curious to see what systems they put in the SF50 especially since they are likely to sell to a lot of people upgrading from SR22s who have no retract time.

 

[Dav8or]

I bet that with modern systems, if Cirrus were to build a retractable version of the SR22, it wouldn't just have a gear horn but it would actually announce "Gear up, Gear up" and as you got closer and closer "Gear up, go around!" or something like that. The plane talks to me constantly about altitude, sink rate, traffic, etc... So I think it could easily be programmed to have a 'smart' gear warning that is much harder to mentally tune out than a gear horn. Not saying that someone wouldn't figure out how to land it gear up anyway, but I think they'd have to try a bit harder...

They absolutely would. That kind of voice alert system is available to retract owners now and can be added to existing planes. It's what I have in my plane. Mine says- "Check landing gear." Our brains process this sort of input much easier and more direct than a buzzer, or horn. It's much like having an instructor sitting next to you tapping you on the shoulder and saying "What have you forgotten?" or simply "Landing gear!"

Like I said above, gear up landings only happen when a pilot is distracted and when this happens, check lists, GUMPS, airspeed variations, gear warning horns, all go out the window. The only last hope you have at that point is, a human voice cutting through the fog of distraction. At least that is the hope. I have tested my system, but thankfully in my last 8 or 9 years of flying Cessna, Piper and now Mooney retractables, I have never come close to a gear up. However I am not so bold as to declare it could never happen to me and that's why I have installed a voice alert system.

 

[Bonchie]

Or do like Piper did way back in the last century and drop the gear for you below a certain pitot pressure (airspeed) and throttle position. It's not cosmic really.

Didn't that go away because someone sued them over the gear coming down on an engine out and limiting best glide distance?

Amazing that such a great, useful innovation would have to be scrapped for everyone because of one instance. A simple override would of sufficed I'd think.

 

[bburnett]

PA30B,

Lyc. IO360, turbonormalized, onboard O2.

She scoots.

 

[Henning]

Didn't that go away because someone sued them over the gear coming down on an engine out and limiting best glide distance?

Amazing that such a great, useful innovation would have to be scrapped for everyone because of one instance. A simple override would of sufficed I'd think.

It wasn't one instance of anything, it was multiple time events and issues. Not remembering the lock out on a high altitude take off can leave you in the trees as well. I made that mistake once, luckily there were no trees and I got the gear sucked back up. Then there were some maintenance issues with it.

 

[RudyP]

It wasn't one instance of anything, it was multiple time events and issues. Not remembering the lock out on a high altitude take off can leave you in the trees as well. I made that mistake once, luckily there were no trees and I got the gear sucked back up. Then there were some maintenance issues with it.

Not arguing with that, I'm sure it is correct but I would imagine in a new airplane being built today you could have a pretty robust auto-extend system.

Those Pipers gear system presumably didn't know if the engine was running, at what rpm, what the flap position was, where the airplane was, at what altitude, airspeed, vertical speed, etc... Now my G1000 based Perspective system knows all of those things and can pretty easily tell if I'm on approach to an airport, on departure or in an engine out situation where I want best glide up to the point of my choosing.

What do modern, glass panel retractable aircraft (e.g., Meridian, TBM, Eclipse, G36, etc...) have in terms of gear warning system these days? The faster planes seem less prone to these issues probably due to greater likelihood of 2 person crews, higher training requirements, better use of checklists but I'm sure it probably still happens sometimes in the owner flown market especially.