How do you expect the TAS to compare between the LSA & Patrol with Rotax 916is?

[Dougla$]

The option for this engine on both models is supposed to be available soon according to the website. Until both models have been flown with this engine, all we can do is guess as to how their cruising speed will compare. But if you had to hazard a guess, how do you expect both to perform?

The airframes appear similar, but there are some small differences such as length, height, wing loading, etc. The LSA also has smaller tires as well a slightly narrower fuselage (I believe it’s 31 in compared to the Patrol’s 32 in). There’s a photo of one with wheel pants, and that would suit me, as I want to be able to land in my backyard (and other grass strips) but not really do any hardcore backcountry landings but still use it as a cross-country plane. The LSA cruises slower than the Patrol, but that’s primarily due to the smaller engine. I’m eager to see how they compare with equal horsepower.

[gregc]

Even if your question could be answered I’m not sure it would be useful in any practical sense. The two aircraft are engineered differently and have different never exceed speeds. Unless you always fly in smooth air, I would think that maneuvering speed would be more relevant. Bob set Vne for the LSA at 140mph. Personally I would be very cautious at anything near that no matter the engine. Perhaps someone with a flying LSA could tell you where they set Va on their airplane to give you a general idea.

[Dougla$]

The Vne is for indicated airspeed. Cruising at high altitudes may not be an issue.

[jaredyates]

There is some additional research opportunity on this. It's not intuitive and I don't think you have it quite right.

http://bearhawksafety.com/LSA/vne.pdf

https://www.vansaircraft.com/wp-content/uploads/2019/01/hp_limts.pdf

[Dougla$]

I didn’t see the article on Bearhawk. I’ve read the Vans article and know what flutter is (and how potentially deadly it can be).

[Utah-Jay]

I was in Fairview bantering the idea of an LSA with a 915/6 and Virgil just shook his head no. He flat out told me that is too much power for the LSA, it would be way too easy to get into trouble with Vne and Vno. Put the 916 on the Patrol and don’t look back. IF you are trying to build an LSA due to budget but still want the Patrol speeds….. save more money.

[Frank]

Bob consulted with the NTSB on a 2022 LSA incident and said the maneuvering speed for the accident airplane was 75 mph.

[Battson]

Unless you needed to go LSA for licensing reasons, I would personally suggest considering a Patrol based on that small insight into your mission profile,

A very light Patrol with a high power to weight ratio will be a much more capable STOL machine and cruise machine compared to an LSA, noting your comments about your mission.

I assume you need STOL, otherwise you'd be looking at a more conventional cross-country ship which goes ~180 kts. Again, a light Patrol will perform better there with the huge flaps and greater engine power, compared to an LSA.

Two seaters are notorious for needing more space and payload for cross country flying, so the Patrol ticks that box and it's faster which is a natural advantage x-country.

It would be interesting to see how a 916iS Patrol compares to an injected Lycoming-powered machine of similar power and weight.

In pure engine cycle efficiency, I assume the Lycoming would probably have a slight edge over a standard Rotax in a mathematical sense, assuming it is leaned correctly. Not having so much frictional loss which comes with higher RPM, greater pressure and tighter rings etc, and gearbox losses - I guess they weigh in. Plus the Lycoming also tends to swing a larger two-bladed prop, which is again more efficient than the props normally mounted on a Rotax. But the turbo will recover a lot of lost energy when looking at the 916iS so it should be an interesting comparison.

I assume the turbo must come with operational considerations, as you don't want to thermally cycle a turbo too often or too rapidly (speaking generally). That's no problem, you just have to fly differently. The Rotax guys who I watch have little concern about making sudden changes to engine power settings, which is quite interesting for a pilot who only flies large air-cooled engines. Every big power change is a decision when thermal cycling is a concern.

[Utah-Jay]

IF I was gonna build another plane with would absolutely be a 916 powered Patrol

[Gigajoe]

What are the Patrols new flaps?

[Utah-Jay]

Gigajoe the new flaps are not yet in production… but I have seen the prototype and they are a game changer. I am not sure of the timeline

[Gigajoe]

Gigajoe the new flaps are not yet in production… but I have seen the prototype and they are a game changer. I am not sure of the timeline

Ah ok. I have a Patrol QB on order with plans for the Rotax. I'll have to ask Virgil about the flaps when I talk to him next.

[Untainted123]

I would think that now that MOSAIC is out, the LSA model is almost redundant to the Patrol. I wouldn’t be surprised to see it fade out of the product line.

[geraldmorrissey]

I like everything about the Rotax except the sound. You have this big beautiful Patrol, you pour the piss to it and it sounds like it has asthma. No way I could live with that no matter the many advantages. But I get why it will be a popular option. Guess I'm old fashioned.

[paulodonnell]

Got to agree with you there, my Patrol is getting a 220HP UL520T motor, arriving in a couple of weeks ... a Rotax to me is like seeing a Harley fitted with a 125cc two stroke with the accompanying whine :-)

[svyolo]

That UL motor sounds like a beast. Is there a provision for a hydraulic CS prop?

[paulodonnell]

Can't use a hydraulic prop with the UL520 but MT or Skymaster have nice electrically operated ones...I'm fitting this four blade Skymaster as it's coming with reverse thrust (Beta) for floatplane operation.

20211102_185442.jpg

[Dougla$]

Keep us posted on the performance of the Patrol with the UL520T! I’ve read where pilots claim that the n/a UL520is doesn’t quite produce the 200 hp as advertised, but it’s still considerably lighter than the o320/360 engines (238 lbs.). But the 520T should still do well.

[svyolo]

The non-turbo versions rate their power at 3300 rpm. The turbo at 2700. Most, not all props have a lower limit than 3300 limit. Kind of a weird claim, as well as not having a hydrualic CS option. Still, I like their engines.

But some of their design choices I don't understand. Maybe the 520T is the first one that really fits.But still no hydraulic CS option.

I still like it.

[paulodonnell]

I use to think that was weird too until I found out why! The reason UL rate some motors at 3300RPM is because they are fitted in many small helicopters...The UL520T is 220hp at 2700.

[Pbruce]

It’s interesting to me that with 5 models of BH, people still want to re-engine and (IMHO) overpower them. I’m not criticizing, just observing. I talked to a fellow who had flown Mark’s BH LSA and he was deeply impressed. He said it was like a roomier cub or champ, delightful to fly but you cruise at 120 mph. It’s hard to see how more power actually improves a plane like that, given that performance is but one (albeit important) parameter of the LSA : ease of building and operating, cost, handling, maintainability. These all add to the magic mix of a great plane like the LSA. I was tempted to build one before I settled on a Patrol. I’d be very reluctant to mess with it much, especially by overpowering this LSA gem. If the balance could be made to work, I could maybe see a 912, UL, Viking 3 cylinder Honda, or even a little radial from Chek. The last thing I’d do is over-power it though.

The heavier Bearhawks can probably tolerate such mods more easily. I can appreciate some benefits of different engines on them and I understand the desire to experiment. I’m as frugal as anyone and I like performance too. But in end I bought a Bob 0-360. I think the price/performance equation will be unbeatable. Ok, I did blow it with a Trailblazer and one electronic ignition. I’m sure I’d have been happy without those too. I just think right-sizing is very sound strategy. What do I know though? I haven’t flown her yet.