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  #221  
Old 09-07-2021, 09:00 PM
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emsvitil emsvitil is online now
 
Join Date: Oct 2019
Location: SoCal
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There is no rotax 918 engine.

If you look at the picture, the middle cylinder doesn't have any exhaust port........ And the middle exhaust pipe ends on the rear cylinder.
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  #222  
Old 09-08-2021, 01:22 AM
Utah-Jay Utah-Jay is offline
 
Join Date: Aug 2021
Location: Heber City
Posts: 23
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Quote:
Originally Posted by bhassel View Post
LOL! - Well that would be a bummer, but you all are probably correct!

Thanks!

Bob

yelp color me fooled Well back to where I belong - LyCons...
Sorry, but yes it was an April Fools Joke. But I would not be surprised if Rotax built a higher HP engine in the near future.

It is a bit of a tough one though, I am about to begin a Bearhawk build and have been flying behind a 915iS for a while and LOVE it. But the BH just can’t be built (barring extensive FWF modifications and fabrication well beyond my abilities) due to the fore/aft W&B. It was designed for an engine in the 300# range, and the 915 is a 187# engine, maybe close to 200# if you tried. But at the furtherest most forward arm it is not gonna stay in the CG envelope. And I am not a fore of a aft CG guy so it was out of the question.

So, with the above being said, will they build a 180hp turbo engine for only the current market? Or will they try to break into the 10’s of thousands of LyConti’s already out there? Would they build a 180hp normal weight for the Vans, Kitfox and Rans crowd and a heavier model for the legacy crowd?
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  #223  
Old 09-10-2021, 11:10 AM
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LAMPSguy LAMPSguy is offline
 
Join Date: Feb 2008
Location: Pensacola, FL
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Default Innovate

Just to be clear, where innovative engineering is involved, some advances can seem magical/impossible/improbable:

35-375 kts

https://en.wikipedia.org/wiki/Ball-Bartoe_Jetwing
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  #224  
Old 09-10-2021, 12:05 PM
David Paule David Paule is offline
 
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Location: Boulder, CO
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Pete Bartoe, who also designed the Skyote biplane, gave a talk to my senior aerospace engineering class back when. He described this and predicted the performance he got, and discussed the technical features. It was built at Boulder, I believe, as a homebuilt.

Dave
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  #225  
Old 09-10-2021, 01:23 PM
AeroEngineer AeroEngineer is offline
 
Join Date: Jul 2021
Location: US of A
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Quote:
Originally Posted by grubbat View Post
If I recall, Vans had a graph with a curve on it that showed the relationship between speed and survivability, using data from I guess years of information...
I vaguely remember having seen something like that, so I did some quick Googling.

Rich Stowell generated the following graph from data off an SAE study about light plane crashworthiness. More details in this IAC article. Notice that the angle (presumably the angle off the horizontal) plays a key role: At 90 degrees nose-down (nose-dive), anything above 45mph is deadly. But at zero degrees (belly-flop) you could survive hitting the ground at 75mph, according to the data.



Ron Wanttaja writes lots of terrific articles about light airplane safety, accident rates, accident causes, etc. If you don't know his work, you must check it out. Below is a graph from this article. Although it ranks kitplanes not by speed but by fatal accident rate, you can't help but notice that the ones in the lower left (safest) are generally the slowest, and the ones on the upper right (more fatal accidents) are the fastest. The RV-4/6/8 are slightly above the line.



Finally, it's no surprise that the automotive industry has all kinds of statistics about this. They're not so relevant to us - because cars are different kinds of vehicles, are built differently and move through space differently - but the trends are interesting. Two graphs below, one from here and one from here.





In the end, I have to admit that I feel a little more peace-of-mind when I fly a slower airplane versus a fast RV because I know that, if I have to make an emergency landing, I'll be more likely to walk away from the slower airplane. I've heard pilots say - and I agree - that "The Cub is one of the safest airplanes out there; It's barely fast enough to kill you"
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  #226  
Old 09-13-2021, 02:17 PM
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smokyray smokyray is offline
 
Join Date: Jan 2005
Location: TX32
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Default RV15 Prototype?

Having been blessed to fly a wide variety of aircraft I definitely have my favorites. High on the list is the F16 and the RV4. Right there with though is my tried and true Maule M5.
The similarities between Vans Aircraft and Maule Air Inc are to the most casual observer uncanny. Both humbly began with quiet genius engineer dreamers building a prototype aircraft in a barn after the factory built aircraft didn't add up. Both aircraft (M4 and RV3 prototype) won best new design award at the EAA convention. Both are legendary in their own rite.

Where they differed was one went into production as a certified aircraft, the other into the most successful kit aircraft company in history. So why the M5 comparison?
My M5 180's (0-360) GW perf numbers are impressive even today, the 0-540 powered models even more so. With equal power (Vans uses the same engines historically) it's a good bar for the RV15 to match or hopefully raise.

Maule M-5-180C -GW Performance Data

Horsepower: 180 Gross Weight: 2300 lbs
Top Speed: 157 kts Empty Weight: 1300 lbs
Cruise Speed: 136 kts Fuel Capacity: 40 gal (65 with Aux tanks)
Stall Speed (dirty): 33 kts Range: 525 nm

Takeoff Landing
Ground Roll: 200 ft
Over 50 ft obstacle: 800 ft Over 50 ft obstacle: 600 ft

Rate Of Climb: 900 fpm
Ceiling: 15000 ft
Wingspan 29'6"
Length 26'3"


So I'm expecting great things from Van with the advent of The Fifteen, although the M5 (M7 and 9) casts a large albeit similar shadow...

V/R
Smokey

Last edited by smokyray : 09-14-2021 at 03:19 PM.
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  #227  
Old 09-13-2021, 03:21 PM
gasman gasman is offline
 
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They did the same display out of a hangar at Santa Rosa Air Center back in the late 70's.
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