jugheadF15 wrote:

Mapleflt wrote: Robertson style STOL kit,

The best part; it could be a round tail, bring it on man let's gooooooooo

Not sure why anyone would want a Robertson, since the Sportsman came out. Much better performance gains.

Sportsman is all cuff, but the Robertson uses some drooping aileron set by flap position, IIRC. Isn't that a much more radical change in wing camber than cuff alone? I'm asking as I honestly am not sure which is more desirable.

Zzz wrote:

jugheadF15 wrote:

Mapleflt wrote: Robertson style STOL kit,

The best part; it could be a round tail, bring it on man let's gooooooooo

Not sure why anyone would want a Robertson, since the Sportsman came out. Much better performance gains.

Sportsman is all cuff, but the Robertson uses some dropping aileron set by flap position, IIRC. Isn't that a much more radical change in wing camber than cuff alone? I'm asking as I honestly am not sure which is more desirable.

I would take a Robertson kit with a sportsman cuff. The best of both worlds.

A1Skinner wrote:

Zzz wrote:

jugheadF15 wrote:

Mapleflt wrote: Robertson style STOL kit,

The best part; it could be a round tail, bring it on man let's gooooooooo

Not sure why anyone would want a Robertson, since the Sportsman came out. Much better performance gains.

Sportsman is all cuff, but the Robertson uses some dropping aileron set by flap position, IIRC. Isn't that a much more radical change in wing camber than cuff alone? I'm asking as I honestly am not sure which is more desirable.

I would take a Robertson kit with a sportsman cuff. The best of both worlds.

A1Skinner wrote:

Zzz wrote:

jugheadF15 wrote:

Mapleflt wrote: Robertson style STOL kit,

The best part; it could be a round tail, bring it on man let's gooooooooo

Not sure why anyone would want a Robertson, since the Sportsman came out. Much better performance gains.

Sportsman is all cuff, but the Robertson uses some dropping aileron set by flap position, IIRC. Isn't that a much more radical change in wing camber than cuff alone? I'm asking as I honestly am not sure which is more desirable.

I would take a Robertson kit with a sportsman cuff. The best of both worlds.

Those two kits compliment one another. But the RSTOL kit alone takes the documented, flight tested and CERTIFICATED stall speed of the Cessna 185 from 56 knots to 37. What the Sportsman adds to that performance is it significantly mellows out the stall characteristics of the RSTOL airplane. Additionally, the aileron gap seals that come with the 185 Sportsman kit return some aileron authority which the RSTOL kit limits.

There’s a lot of talk about Robertson STOL kits out there. And most of the negative stuff is from folks who’ve never actually worked an RSTOL equipped wing. It’s an amazing modification, made even better with the Sportsman kit. That’s based on several thousand hours working RSTOL airplanes.

If I could put one on my 175, I’d do it in a heartbeat.

MTV

The greatest advantage of the RSTOL for me is that it works on the trailing edge and not the leading edge. This allows the RSTOL to generate the same amount of lift at a lower sight angle. I probably wouldn't be able to take advantage of the Sportsman cuff as much being that I avoid high sight angles as much as possible, especially when landing off airport or on more challenging strips. I'm sure the Sportsman would let me fly slower, but I just can't get the nose that high and land the plane safely at the same time.

Every time I get in an airliner I am amazed by the wing technology. I can’t help thinking that we are flying 2x4s in comparison. I was very impressed by Scrappys wing, I think we have a long way to go.

Squash wrote:

Oregon180 wrote:Looks pretty cool! Seems to have shocks on the tailwheel. Huge fowler flaps as well.

Kind of surprising/weird that it seems to have both a trimmable tail and trim tabs on the elevators. Maybe just a prototype thing.

It may be that this is a stabilator like on a Cherokee versus a trimmable stabilizer with elevator that are found on skywagons and super cubs. If that is the case, it would need a trim tab or anti-servo tabs as was mentioned. From those angles it is hard to tell.

I think you are right, I can't see any obvious hinge line for an elevator.

That would be an uncommon choice for a low-tail backcountry aircraft. I wonder if a rock strike causing significant physical or aerodynamic damage could lock up the controls and/or affect pitch authority? We've seen what a rock can do to a semi-monocoque stabiliser.

I guess other backcountry ships like the Helio already use that design (I think), although they are significantly more heavily built.

Robertson or Sportsman is not compatible with the shape of a Van’s airfoil. Assuming they keep the same airfoil. You may be able to droop the ailerons somehow, who knows, maybe they already have incorporated this into the design, maybe they haven’t. But a cuff, be it a Sportsman cuff or the cuff in a Robertson kit would be useless on a Van’s wing. If it were, it would probably destroy what makes a Van’s airfoil such a great airfoil for the wide speed envelope it currently has.

VG’s may or may not help, but who knows at this point.

Kurt

Battson wrote:Straight sprung main gear is not a surprising choice from RV, but commonly a weak point in the backcountry from a maintenance and piloting perspective. Likely deliberate a sacrifice to preserve airspeed and to stay in familiar territory. I like oleo gear much better

Huh? Maintenance on a straight sprung gear? That is one of its advantages, there is no maintenance. There are no-rings or oil leak to worry about, no bungies to replace. There have been a few bearhawk’s that have collapsed those oleo mains..

Oh ya, the springs themselves are usually fine, depending on the design... Gear boxes though, I have lost track of how many machines I've seen which needed gearbox work...

To be fair though, most of those are 50 to 70 years old now. I can't think of many new designs with gearbox issues - apart from the Tundra, but then again, I can't think of too many issues with the gear legs on 70 year old Cubs either.

Bearhawk gear collapses are few and far between, and were all serious pilot errors or scratch-built welding issues to my knowledge. I have just fully disassembled and maintained mine after 1000hrs, the most experienced IA's comment "That would have been good for another 20 years, don't maintain it again for another 10 years at least".

Different designs have different advantages, plain and simple, it's not about one aircraft model vs another model.

https://www.youtube.com/watch?v=-FLjPoxsk7Y Not your Cessna's spring gear.

Oh you are right - looks like it’s spring steel/aluminum gear, with some type of hinge point at the top - maybe with some type of dampener to help with spring back, sounds like he says in the video when rocking the wings “all the shock absorption is inside the plane to reduce drag” Interesting!

Yep, something very different there.

And, Kurt, what makes you think Van’s is using the same airfoil on this plane?

MTV

As an LSA pilot, I'd be very jealous if it wasn't for us getting thissoon

Big fowler flaps? Check
Cantilever wing? Check
Slats? Check

I still think the RV-15 is a better looker, though. And probably significantly beefier as well.

GB wrote:https://www.youtube.com/watch?v=-FLjPoxsk7Y Not your Cessna's spring gear.

Yes that was described in an earlier video too. From a shock absorption perspective it looks like it could perform better than pure spring gear, but I bet you could rock a pint-sized Cessna like that too, if that's the yardstick. Pilot reports after a botched landing will be the best yardstick - does it bounce when you put it down hard...

From a durability standpoint though, it's still a 3ft long lever arm pulling on a narrow bracket only 8 inches wide. It's simple physics, it's going to experience more force and wear out faster compared with gear with two points of attachment, and huge steel fittings. Like has been said, it's appears to be "backcountry capable", rather than a truly rugged backcountry design.

Still, that should be more than acceptable for 90% of their customers! I have absolutely no doubt that thing will be presold at Osh way into 2025...

I can't imagine for one second that Van's has fitted the RV-15 with a traditional RV airfoil. That would be a serious mistake if they see their intended market in the "backcountry" at all. In fact if I was Van's a cuff might very well be a "upgrade" to the basic kit along with other "off-strip" enhancements. It does look like the ailerons "droop" somewhat with the flaps so either a bit of "Robertson" or deHavilland design ideas being incorporated into the wing maybe.

Battson wrote:

GB wrote:https://www.youtube.com/watch?v=-FLjPoxsk7Y Not your Cessna's spring gear.

Yes that was described in an earlier video too. From a shock absorption perspective it looks like it could perform better than pure spring gear, but I bet you could rock a pint-sized Cessna like that too, if that's the yardstick.

Yes you can rock a Cessna, you can rock any GA aircraft if you have a dude on each wingtip, but that was not the point (or yardstick) of what they are showing in that video. If you were to do that in a Cessna it would keep rocking back and forth a bit after you let go from rocking the wings. Its what’s causes the Cessna to waddle or rock side to side when going over big holes and rocks. It’s the nature of a sprung gear, it’s “simple physics”. The downward force creates energy, that energy is returned as upward force and there is nothing to absorb that return energy so you get the Cessna bounce, or waddle, you are transferring some of that energy back and forth between the left and right gear. What they are showing in that video is that when there is a downward force on the gear, the resulting upward force, or energy if you will, is absorbed by the shocks. So you don’t get the bounce of a true Cessna style sprung gear, or the waddle you get from going over rough terrain. A pint sized Cessna would 1) probably had the opposite tire come off the ground as the gear has no pivot point, and would act more as a lever 2) have keep rocking back and forth after they let go, where as the rv-15 did not, it pretty much came back to straight and level with no rocking motion, Much like how the oleo gear absorbs that return energy. The jury is out on how durable this new design will be, from the pictures the gear box looks substantial, but good on Vans for pushing the envelope.

I’m looking forward to seeing how it performs and the durability, not in comparison to a tricked out supercub or a Just Aircraft with a gear leg that attaches to the midpoint of the door frame.. but to a Cessna 140/170, Luscombe,Murphy Rebel, Glastar sportsman, etc, and even current Vans owners that want to get in on the backcountry wave. A very capable backcountry plane, but still fast. When you have a headwind, and you look down at the road below, cars are not going faster then you. All while burning less then 10gph. With the industry leader in kit planes backing it, top notch support, top notch builder manuals, latest kit technology to make assembly easier and faster with the fit and finish as good as many certified aircraft, all metal skin, a built in network of 3rd party companies building mods, and a kit with pretty affordable prices. I think there is a market there, and they will dominate that market.

Varanger wrote:As an LSA pilot, I'd be very jealous if it wasn't for us getting thissoon

Big fowler flaps? Check
Cantilever wing? Check
Slats? Check

I still think the RV-15 is a better looker, though. And probably significantly beefier as well.

That STOL cruiser is a nice looking plane, much nicer than the RV-15 and I like the cantilever wing. And, is that a tapered wing?

mtv wrote:Yep, something very different there.

And, Kurt, what makes you think Van’s is using the same airfoil on this plane?

MTV

Nothing other than they have found an airfoil they like with the other airplanes. I thought they MIGHT use it on this airplane, maybe they will, maybe they wont.

Kurt

C180_guy wrote:

Varanger wrote:As an LSA pilot, I'd be very jealous if it wasn't for us getting thissoon

Big fowler flaps? Check
Cantilever wing? Check
Slats? Check

I still think the RV-15 is a better looker, though. And probably significantly beefier as well.

That STOL cruiser is a nice looking plane, much nicer than the RV-15 and I like the cantilever wing. And, is that a tapered wing?

Yeah, the wing is tapered as well. I mentioned this in the LSA section, and some guy pointed out that he thought the airfoil was unusual for a STOL plane. It's not easy to judge by the pictures, but it might look like a faster airfoil, wich also means less slow speed lift. I guess the slats and the flaps mitigate that a bit. The stated stall speed with full flaps is 30.5 knots at 600kg/1320lbs.

I do think the STOL Cruiser is built primarily for the EU market. We're not allowed to land anywhere in the backcountry that isn't private land. You can land in a private field, but you are limited to a certain number of landings and takeoffs in a year. What we have are a bunch of short, but still quite good mountain and forest grass strips. People also tend to like to go on medium trips, and we bring either clothes and stay in a hotel, or we bring backpacking gear. Not half a dead moose. So instead of making a hardcore bushplane, they've probably aimed for something that will get you in and out short strips in the sidecountry, and then relatively fast to the next strip.

It has been designed in cooperation with the Prague Technical University, and partially funded by the Czech government, so atleast it had a very good starting point for being a soundly constructed aircraft.

EDIT: But I didn't want to derail this thread either... You're welcome to join in the thread over at the LSA section If I had a PPL instead of an LSA license, I think the RV-15 would fit my bill very nicely. I am not brave or experienced to go land at gravel bars, just sidecountry for me. The problem is the same as always: money.