Does an engine like this exist?

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observer79

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observer79
First post.. my question involves a proposed aircraft, to be made by a truck company, and I am seeking some information to sort out realism vs fantasy.

The aircraft in question is the Workhorse "Surefly", which looks like an overgrown "drone" quadcopter. (I can't post links, so you'll need to look it up if interested.) The company promoting it claims a lot of wild things, which I don't mean to address here.

But one of the key claims is that it will use "a 200 hp, 6,000 RPM av gas engine".

While I don't think much of their design, I'm guessing they at least did some kind of search to claim the existence of such an engine. My questions to all of you are as follows:

Is/are there any candidate(s) that fit this description today? Anything that would be out there soon? Are any of them useable on an aircraft that would be certificable as a production (i.e., not Experimental) aircraft?

Thanks for any help! Please know that partial knowledge or even outright speculation is still good; links to additional info GREATLY appreciated.
 
I'd say some sort of jet or gas turbine except they generally use jet-A, not av gas, and I think they spin faster than 6,000 PRM. Use it as a turbo-shaft engine.
 
Cap'n Jack said:
I'd say some sort of jet or gas turbine except they generally use jet-A, not av gas, and I think they spin faster than 6,000 PRM. Use it as a turbo-shaft engine.
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Thanks, Captain.

Certainly a converted helicopter APU (or similar small gas turbine with a reduction gear) would work, but the company was pretty explicit about avgas. (It would seem Jet Fuel would be preferred because it's cheaper and easier to get.) FWIW they have also said "automotive gas" which would be even more unlikely.
 
A 200 horsepower 6,000 rpm gas engine is not that unusual. There are too many to guess which one.
 
Vance Breese said:
A 200 horsepower 6,000 rpm gas engine is not that unusual. There are too many to guess which one.
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Thanks, Vance. I have to say I'm surprised in this output and speed range (expecting mostly direct drive once above ~150hp), but that's why I'm asking here -- to tap some real expertise.

Could you please name me a few w/links (certified for flight use on aircraft other than experimental) that I could look at?
Much obliged, sir.
 
observer79 said:
Are any of them useable on an aircraft that would be certificable as a production (i.e., not Experimental) aircraft?
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Sorry, I missed this part. I don't know of any 200 horsepower 6,000 rpm engines that are presently certified for standard category aircraft.
 
I have never heard of such a certified engine; I doubt such a thing exists. Probably they're basing their specs on an auto engine.

But as far as sorting out realism vs. fantasy, I'd say this one is firmly in the "fantasy" category.
 
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Dana said:
I have never heard of such a certified engine; I doubt such a thing exists. Probably they're basing their specs on an auto engine.
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And I'm guessing the engine drives a generator to power electric rotor motors.
 
Vance Breese said:
Sorry, I missed this part. I don't know of any 200 horsepower 6,000 rpm engines that are presently certified for standard category aircraft.
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No worries. Even links to, say, the top three that have found their way to homebuilts, etc. may be helpful.
Maybe Workhorse envisions funding the cert of a commonly-used, well-proved design from the homebuilt world. (On that topic: how long would a cert process take for an engine with good real-world performance on Experimental or homebuilt planes?)
Any smartening of my aged brain on this topic helps.
 
Vance Breese said:
A 200 horsepower 6,000 rpm gas engine is not that unusual. There are too many to guess which one.
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Outside of racing cars, are automobile engines generally run at 6,000 RPM continuously? I'm certainly no engine expert.
 
FWIW, I do know about the Eggenfellner E6, which at a rated 240hp is a bit over what's needed, and at 3 to 3.6 liters these seem a little beefy for the job. Nonetheless, change the gearbox to a speed increaser to run a high-speed PM generator (about 4x to get ~25krpm rotor speed) would get you to the mission requirement. With 300 or so of these sold to Van RV-ators there's surely some service data to be tapped.
 
Cap'n Jack said:
Outside of racing cars, are automobile engines generally run at 6,000 RPM continuously? I'm certainly no engine expert.
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Not at all, but some bright people have been converting auto engines (like the Subaru opposed sixes and the Honda V-tech based Viking) to operate in this speed range for a couple of decades. Again: as a non-participant in GenAv I don't know of any that are on planes without an "Experimental" sign above the door, but I admittedly don't know anything anyhow!

Edit: I didn't mean the engines would operate "for a couple of decades" -- I meant these folks have been on the job making it happen for that long. I suspect TBOs are shorter than a designed-for-purpose engine, but don't know.
 
The indy cars I worked on back around 2000-2003 were turning 16-18000 rpm and putting out 800 + horsepower ( and about 150 ft/lb of torque) so its not out of the realm of reality. I know VW had a couple gas engines that put out more than 200 HP at about 6000 rpm too.....so does toyota, nissan, ford......
As for airplane engines I'm guessing if they're a truck builder why would they care to use a certified plane engine? Obviously if they're building quad copters they're not interested in much aviation reality anyway.
just my jaded opinion
Frank
 
BiffJ said:
The indy cars I worked on back around 2000-2003 were turning 16-18000 rpm and putting out 800 + horsepower ( and about 150 ft/lb of torque) so its not out of the realm of reality. I know VW had a couple gas engines that put out more than 200 HP at about 6000 rpm too.....so does toyota, nissan, ford......
As for airplane engines I'm guessing if they're a truck builder why would they care to use a certified plane engine? Obviously if they're building quad copters they're not interested in much aviation reality anyway.
just my jaded opinion
Frank
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Biff, that's exactly my perspective but I don't have sufficient knowledge to back my PoV.

The whole "Surefly" story is a giant tale, IMO, in order to create enough interest for a big equity raise. Long ago I was once involved in aerospace businesses (though I am clueless about general aviation) and I can't stand dopey claims like Workhorse is making.

As a "truck builder" they still have to meet the same standards as the "legit" guys (Cessna, Robinson, etc.) and they state an understanding of that fact. But they say things like certification "in two years" for a power and flight control architecture that has never before been certified. I understand the flight control side, but I really am a neophyte on engines in this category.

Edit: BTW I envy your Indy engine experience.
 
http://workhorse.com/surefly

It is meant to be used as a generator. I don't see "Av" gas requirement anywhere, only "gasoline". Or any engine specs in general. This is all there is "Gasoline Piston Engine drives dual generators to provide power to prop motors"
 
genna said:
http://workhorse.com/surefly

It is meant to be used as a generator. I don't see "Av" gas requirement anywhere, only "gasoline". Or any engine specs in general. This is all there is "Gasoline Piston Engine drives dual generators to provide power to prop motors"
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Thanks, genna. They released this through PR Newswire with additional details (hope I get to post the link; if it doesn't work search "PR Newswire Workhorse Group Inc. Unveils SureFly") and read the "Specifications include:..." list.

https://www.prnewswire.com/news-rel...pecifications-opens-pre-orders-300475615.html

Edit: Also, I know it's to be used as a power source to spin a generator. But since it is the primary source of propulsion power (sent to the motors) it would seem that many cert requirements would shared (e.g., environmentals, fuel system reqt's etc.).
 
observer79 said:
Thanks, genna. They released this through PR Newswire with additional details (hope I get to post the link; if it doesn't work search "PR Newswire Workhorse Group Inc. Unveils SureFly") and read the "Specifications include:..." list.

https://www.prnewswire.com/news-rel...pecifications-opens-pre-orders-300475615.html

Edit: Also, I know it's to be used as a power source to spin a generator. But since it is the primary source of propulsion power (sent to the motors) it would seem that many cert requirements would shared (e.g., environmentals, fuel system reqt's etc.).
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From the link you posted. Seems like MoGas:

Specifications include:

  • Vertical take off and landing
  • Onboard GPS navigation system
  • Static ports and a heated pitot tube for altimeter and air speed measurements
  • Detect-and-avoid sensors
  • Maximum flight distance: 70 miles
  • Maximum altitude: 4,000 feet flight ceiling
  • Maximum payload: 400 pounds
  • 200 horsepower at 6,000 RPM aviation gasoline engine
  • Battery backup system with max theoretical battery power of 20.8 amp hours
  • 8 propellers, 4 propeller arms
  • Carbon fiber fuselage, propeller arms and propellers
  • Fuel: premium unleaded 90 octane gasoline
 
I think someone seriously screwed up this news release. I can't quite tell if this means Av Gas or aviation engine, gasoline. There is no "premium unleaded 90 octane" AvGas, however
  • 200 horsepower at 6,000 RPM aviation gasoline engine
 
genna, many thanks; now I see that 90 octane unleaded and "aviation gas" don't fit together.
This is yet another thing that calls into question Workhorse's understanding of their assertions of "certification in two years".
 
200 hp to move 400 pounds?

Then there is:
"Battery backup system with max theoretical battery power of 20.8 amp hours"
Hmmm....
200 hp is about 150,000 watts iffen I didn't slip a decimal point.
They don't give a voltage for their battery system, but just for smiles and giggles, lettuce assume 100ish
That puts us in the 1,500 amp range.
20.8 amp/hours divided by 1500 amps gives us nearly 60 seconds of backup.

Oh, wait... nevermind
http://workhorse.com/surefly
says "Dual Lithium Battery Packs: 7.5kWh each, used for emergency landing power (5 minutes)"
OK, as long as they have the story straight.

But that 200 horses moves the 400 pounds at a full 70 mph. Hard to beat that kind of efficiency.

Probably looking at the engines developed by Moller for his Skycar.
 
Certifying a man carrying quadcopter is gonna be a be a bear anyway, so getting a UL power or some other non-certified engine approved won't be their biggest hurdle.

Someone's eventually gonna pull something like this off, but I'm not putting my money on a truck company to be the first...
 
Workhorse is not really a "truck company", in that they don't have a standing record of building and selling trucks. They are a start-up, whose first product was supposed to be a truck. TTAC was not entirely impressed with their approach of re-bodying a Silverado with carbon fiber first:
http://www.thetruthaboutcars.com/2017/09/up-close-with-the-workhorse-w-15-ev-truck-driveways/

The SureFly appears to be an attempt to pivot away from the W-15, which is almost a guaranteed failure at this point.
 
Thanks to all who have commented and assisted with your knowledge. I think I have sufficient insight now into the primary power aspect of Workhorse's "plan".

BTW, to zaitcev (any relation to Vasily?): Workhorse is a "startup" in the sense that the company as we currently know it is relatively new(-ish), having started as AMP Electric Vehicles in 2007 with a 2010 IPO, trading on the OTC boards. They purchased the name and assets of Workhorse, changed their ticker symbol, did a reverse split of the shares and got listed on NASDAQ. They have delivered a couple of hundred range-extended electric Class 5/6 trucks to UPS along with small orders (<10 each) to various companies, all at an eyewatering loss. Their truck manufacturing line was and remains real, although the actual output has always been small.

Very speculative companies listing on the Naz love to call themselves "startups" for as long as they can in order to attract vulnerable investors hoping for a ten bagger. Some data (all rounded) will lead you to wonder where they're headed...
Trailing twelve months revenue: $7M
Trailing twelve months income/(loss): ($29M)
Cash consumption last quarter: ($7M) -- that's after a $12M equity raise
Accumulated deficit: ($80M+)

Finally, FWIW, based on current share price the company has a market cap of over $100M, which is nuts.
 
Cap'n Jack said:
Outside of racing cars, are automobile engines generally run at 6,000 RPM continuously? I'm certainly no engine expert.
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You don't typically have automotive engines running at that high of RPM for extended periods because that would be very noisy and inefficient. That said, there isn't necessarily a reason why they can't. Expect a shorter engine life than you'd see on the street.
 
Bill Jennings said:
And I'm guessing the engine drives a generator to power electric rotor motors.
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Oh no! Not this again. lol. At least this would have a somewhat useful application to get the power out to those rotos... otherwise using an engine to power a generator to power another motor is just silly
 
NoHeat said:
A tank of gasoline stores 100X more energy than a lithium battery of the same weight. So it’s not silly.
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Pardon, maybe my point was not well delivered. What is silly is taking one form of mechanical energy, losing a bunch of it to heat losses, and then turning it into another form of mechanical energy. An internal combustion engine connected directly to a propeller is always going to be more efficient than an internal combustion engine connected to a generator which is then connected to an electric motor which is then connected to a propeller. In this application it makes sense, because all of those rotors need an easy way to have the power sent out to them. That's why my post said for this type of application to make sense, but otherwise it is silly to jam a generator and electric motor in between a perfectly good engine and propeller because you'll have heat losses. But I didn't want to rehash this whole thing from the other hybrid plane thread hahs
 
Ok, so you are taking for granted that you have a gasoline engine and a rotor and the remaining problem is that you just need to couple them.

I was taking for granted that you have an electric motor and a rotor, and the remaining problem is that you just need to power the electric motor.
 
Tantalum said:
Pardon, maybe my point was not well delivered. What is silly is taking one form of mechanical energy, losing a bunch of it to heat losses, and then turning it into another form of mechanical energy. An internal combustion engine connected directly to a propeller is always going to be more efficient than an internal combustion engine connected to a generator which is then connected to an electric motor which is then connected to a propeller. In this application it makes sense, because all of those rotors need an easy way to have the power sent out to them. That's why my post said for this type of application to make sense, but otherwise it is silly to jam a generator and electric motor in between a perfectly good engine and propeller because you'll have heat losses. But I didn't want to rehash this whole thing from the other hybrid plane thread hahs
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Efficient, maybe. But very problematic for this application(assuming this application is viable). You have multiple rotors. It's way easier to do it with multiple electrical motors than one gas engine connected to all these rotors. On top of it, there is a backup redundancy with battery. The generator->electrical motor loss is minor. Or even non-existent compared to complicated transmission setup Running the engine in a single efficient mode rather than all over the RPMs also helps. This setup is very common: locomotives, some cars.

Again, this is all assuming this is even viable and they did their homework...

EDIT: Basically the same thing you said :)
 
genna said:
It's way easier to do it with multiple electrical motors than one gas engine connected to all these rotors.
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For sure, it makes perfect sense for this. Everything is a compromise in aviation
 
FWIW, Rotax makes marine engines with that kind of horsepower and RPM.
 
Cap'n Jack said:
Outside of racing cars, are automobile engines generally run at 6,000 RPM continuously? I'm certainly no engine expert.
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Not in cars, but it's quite common in personal watercraft and jet boats.

Doesn't the Rotax 912 typically run at 5000 + RPM?
 
My 1100cc twin motorcycle can do that all day for 52K miles so far.
 
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