Let's discuss alternative engines!

[Kaveman]

The link to AIE can be found on the Badlands engine page, as I'm sure you all have looked and drooled. Then you saw the price! 17k+
To be fair, I contacted them about seven years ago, and the quote was 16k, so inflation hasn't hit them too hard, apparently. Needless to say that large RC project ended up electric.

Ten years ago, I was a moderator for a motorized bicycle forum, of all things, and a topic of great interest was a "new" rotary engine from a company called Liquid Piston. Essentially is an inside out Wankel, where the rotor is an oval and the housing is the magic Dorito shape. Allegedly scalable from 3-300 horsepower, multi fuel capable, low vibration, low noise, you name it, they claimed it. They even had a working engine in a go-kart as a demonstrator. Well, they did land a DOD contract. They build APUs, Auxiliary Power Units, for tanks and artillery pieces. There must be something there, right?

You can buy liquid piston stock, you can even invest in the company directly, but they have yet to answer my emails. As far as I can tell, their engines are not publicly available. I sent new email to the contact info on their website a month ago, nothing. My disappointment is palpable. I can't even find out if it's just too expensive to bother with, like the AIE unit. I can't imagine that the DOD decided to mount $17,000 generators to the side of multimillion dollar tanks and howitzers, but I've seen the US military pull some insanely stupid stuff.

[Mountain Cat]

Ultralight engines are never really going to have a long life span (TBO). They are run in the higher RPM range most of their life in unbearable conditions(high heat) and are mistreated by the owners. A two stroke engine can survive in these conditions for 300-500 hrs or so. Most 4 strokes will self-destruct in half that time running in the same conditions. Of course, there are exceptions to most everything. It will be interesting to see how many hrs the Thump-Air goes before complaining. A Polini running at 8000 RPM can go 150-200 hrs before parts need to be replaced and good for another 200 hrs or so. I have no doubt that with proper care, it will make it to 400 hrs. We keep looking for a "add gas and go fly" engine and it probably won't exist without a hefty price tag.

[Kaveman]

While "Add gas and fly" would be nice, I've never smoked anything that would make me dream that big!

It's not that there's no alternatives out there, it's just most are far too heavy. I pointed out the two rotary engines I knew of first, because I know they list great power to weight ratios.

The thump air is promising, but it really is just a built up Honda clone. Those things were designed to run generators, not fly. If we're going to get excited about that, maybe we should look at some of it's competition, like the Kohler and Kubota small diesels.

Perhaps since the STOL drag guys seem to like snowmobile engines, maybe there's a motorcycle powerplant out there just waiting to be flown.

Maybe the question I need to ask is, just how much horsepower is enough? Let's just say for our gross weight? How much woopow do we need? If it's all about torque, maybe we really should be thinking about diesel?

[Mountain Cat]

I've always thought that there was a cycle engine or ATV engine out there that would make a dandy UL engine. Many have tried and failed but the hunt goes on. Most of the new ideas are coming from across the big pond now. The Polini, the RMZ 500, and a few others. But there isn't much return on investment for a dedicated UL engine. So most have to develop a multi use engine. We are all chasing that mystical perfect engine.

[Badland-F5 Pilot]

While "Add gas and fly" would be nice, I've never smoked anything that would make me dream that big!

It's not that there's no alternatives out there, it's just most are far too heavy. I pointed out the two rotary engines I knew of first, because I know they list great power to weight ratios.

The thump air is promising, but it really is just a built up Honda clone. Those things were designed to run generators, not fly. If we're going to get excited about that, maybe we should look at some of it's competition, like the Kohler and Kubota small diesels.

Perhaps since the STOL drag guys seem to like snowmobile engines, maybe there's a motorcycle powerplant out there just waiting to be flown.

Maybe the question I need to ask is, just how much horsepower is enough? Let's just say for our gross weight? How much woopow do we need? If it's all about torque, maybe we really should be thinking about diesel?

I have to disagree. Scott has put a lot of effort into modifying the engine to be much stronger and lighter than the original design. Scott has a very nice shop and machines many parts for the engine to enhance it. I've seen the conversions in the past, and most are not much more than motor mounts and brackets. With the new wave of 4 stroke conversions, there's much more engineering going into the conversion. I could be totally wrong on this or this is just wishful thinking, I guess we'll all find out in the next couple of years if we have something new or that this is all a wash, rinse, repeat of the past modified engines of promise.

Todd

[Kaveman]

Todd, I built the 350 small block in my suburban. I used quality parts, many aftermarket and performance modifications, etc. It did not magically become a "Kaveman 350" it's still a small block Chevy, and still has all the inherit issues of a pushrod V8.

The thump air is a very nicely built Honda clone. Thinking otherwise is deluding yourself. If I take the engine off my log splitter, pull the shrouds off and throw some shiny at it, you'd never know the difference, just sitting there. I'm sure Scott has done a lot of work, but I'm also sure that the engines are meant to run generators and water pumps etc. They are designed to be stationary engines, and start doing silly things when you put them on a go-kart, let alone an aircraft. How has Scott solved the oiling problem? That's an issue that has to be dealt with as soon as you bypass the governor and push on 4,000 rpm. That's what that thing was designed for, 4k, sitting still, making air, or moving water.

Why is the VW bug so capable off road? The nazis designed the suspension to support a machine gun turret on the top. That's why the old bug can run the Baja 1000 basically stock, and a Geo Metro can't make the start line. Just because Scott has put a lift kit on a metro, does not a Baja Bug make.

[Mountain Cat]

I wish Scott the best and hope it's a big success. He has put in the time and effort to make it work. Same as Chris has put in with the Badlands.

[Badland-F5 Pilot]

I wish Scott the best and hope it's a big success. He has put in the time and effort to make it work. Same as Chris has put in with the Badlands.

Exactly. After speaking with Chris on our last virtual fly-in I have much confidence in the work he's put into the engine. I rebuilt the engine in my 73 Chevy Vega and made that little 140cc 4 banger sing. Friends and I built engines and drag raced in high school. Those engines were street drivable, lasted almost identical to a stock engine, and yet put out a lot more power. We also went to The Tripple M Raceway a lot.

It all comes down to deciding what you wish to do and how you're going to get to that goal.

Todd

[Badland-F5 Pilot]

Todd, I built the 350 small block in my suburban. I used quality parts, many aftermarket and performance modifications, etc. It did not magically become a "Kaveman 350" it's still a small block Chevy, and still has all the inherit issues of a pushrod V8.

The thump air is a very nicely built Honda clone. Thinking otherwise is deluding yourself. If I take the engine off my log splitter, pull the shrouds off and throw some shiny at it, you'd never know the difference, just sitting there. I'm sure Scott has done a lot of work, but I'm also sure that the engines are meant to run generators and water pumps etc. They are designed to be stationary engines, and start doing silly things when you put them on a go-kart, let alone an aircraft. How has Scott solved the oiling problem? That's an issue that has to be dealt with as soon as you bypass the governor and push on 4,000 rpm. That's what that thing was designed for, 4k, sitting still, making air, or moving water.

Why is the VW bug so capable off road? The nazis designed the suspension to support a machine gun turret on the top. That's why the old bug can run the Baja 1000 basically stock, and a Geo Metro can't make the start line. Just because Scott has put a lift kit on a metro, does not a Baja Bug make.

You may wish to talk to Scott before making such statements. Scott has done much more than the cosmetics mentioned.

Todd

[Kaveman]

Ok, we're stuck here. Like I said, ALTERNATIVE ENGINES.

Oh gentlemen of the Wise Council, allow me to plead this case.

I present to you a link


Here are some photos for your review:

You can see the ancestry and thus the line of logic.

[Kevin]

Is anyone considering a Half VW on their Badland Aircraft? Approx 37 hp, 85 lbs. Air cooled, no prop reduction, direct drive. A lot of them flying, especially on Legal Eagles. Per Scott Casler's Hummel Aviation site $4,300, assembled and test run.

I've got 40 hrs behind a four cylinder VW in a Sonerai I. The engine topped out at 3600 rpm and cruised smoothly at 3200 rpm. Never missed a beat.

Thanks,
Kevin

[LA F2 Flyer]

I would be curious to see how difficult it might be to make official UL weight with a 1/2 VW engine...I love the look and the sounds. The reliability is also a plus...weight may be the only issue with it.

(The price isn't bad, either, considering!)

[Badland-F5 Pilot]

I'm looking at several options. I do like the reliability and more important to me, the lower fuel burn of a 4 stroke. My original choice was the Hirth F-23 twin two stroke. It's a real nice engine and 1000 hours TBO. There are some drawbacks to it. The fuel injection has been a problem for some users. It appears, and this is speculation based on what I've been told, is that the fuel injection module is not redundant. If it goes bad, you now have no engine! I'm also looking at V twin conversions, 4 stroke engines. I want something with slower RPM, longevity, and excellent fuel burn.

Todd

[Kevin]

I think a potential problem with the half VW may be fuel supply. The Badlands doesn’t easily lend itself to gravity flow from tank to carb like the forward fuselage mounted tank on the Legal Eagle. Most two cycles have vacuum powered fuel pumps. Not so on the VW. An electric pump would add weight.

[13brv3]

I think a potential problem with the half VW may be fuel supply. The Badlands doesn’t easily lend itself to gravity flow from tank to carb like the forward fuselage mounted tank on the Legal Eagle. Most two cycles have vacuum powered fuel pumps. Not so on the VW. An electric pump would add weight.

The v-twins all use pulse pumps like 2-strokes always have, so I wonder if the 1/2 VW could do that as well? I have more engines than aircraft, and sadly no quick solution to that problem.

Rusty

[LA F2 Flyer]

I think a potential problem with the half VW may be fuel supply. The Badlands doesn’t easily lend itself to gravity flow from tank to carb like the forward fuselage mounted tank on the Legal Eagle. Most two cycles have vacuum powered fuel pumps. Not so on the VW. An electric pump would add weight.

Hmmm...I wonder how difficult it would be to put the fuel tank between the wings. The immediate issue that comes to mind would be interference of the flaperon cables...

[Badland-F5 Pilot]

I think a potential problem with the half VW may be fuel supply. The Badlands doesn’t easily lend itself to gravity flow from tank to carb like the forward fuselage mounted tank on the Legal Eagle. Most two cycles have vacuum powered fuel pumps. Not so on the VW. An electric pump would add weight.

Hmmm...I wonder how difficult it would be to put the fuel tank between the wings. The immediate issue that comes to mind would be interference of the flaperon cables...

Don't forget the issues with folding wings! I've seen some pretty small fuel pumps, and it's not like the UL engine is going to be drinking a lot of fuel. I wonder if there's the possibility of a mechanical running off the crank shaft? The mechanical though may weigh in more than an electric.

Todd

[Kevin]

I think you could put a fuel tank in the wings. Actually two. To get five gallons you would only have to put a 2.5 gallon low profile tank in each wing and T the lines together enroute to the engine. I might include a small header tank to insure no fuel flow interuption.

How bout putting the fuel in the main spar. Filler on the outboard end?

[LA F2 Flyer]

Fuel in the main spar isn't a bad idea...it has it closer to the CG than the current location, which is an added bonus. It would need to feed evenly from both spars, I would imagine, or you potentially end up heavy on one wing.

[Kevin]

Fuel in the spars would go to a T fitting and then to the engine. This is how many certified high wing airplanes route their fuel. The Cessna 150 for example only has an on and off fuel selector. Gravity will keep the fuel balanced. The tank with the most fuel will supply fuel at any given time. Some planes with this wing tank setup like Super Cubs have a header tank prior to the firewall to insure fuel flow in the event of upsetting the flow due to turbulence etc. The header tank can be very small.

[Kevin]

Does anyone supply a V-Twin engine package, or a belt reduction setup for a V-Twin?

[13brv3]

Does anyone supply a V-Twin engine package, or a belt reduction setup for a V-Twin?

I don't think I've heard of any company supplying v-twin packages at the moment. Ace sells a good belt redrive, but it takes months to get. I've been testing a Briggs model 38 (23HP) like Leonard and others have used, and it's running well enough that I'd bolt it on a plane if I could find a suitable candidate. Max HP I've measured with an Eiffel club is 38 HP at 5600 RPM using a 1.8 belt drive. Total weight minus prop is around 73 lbs with oil. When my Badland kit eventually arrives, I'll be using the AIXRO XP-40 rotary engine I already have downstairs, so the Briggs was just a fun project. At some point I'll sell the Briggs if I don't find something to put it on soon. I'm not quite done playing with it though.

Rusty

[Badland-F5 Pilot]

Does anyone supply a V-Twin engine package, or a belt reduction setup for a V-Twin?

I don't think I've heard of any company supplying v-twin packages at the moment. Ace sells a good belt redrive, but it takes months to get. I've been testing a Briggs model 38 (23HP) like Leonard and others have used, and it's running well enough that I'd bolt it on a plane if I could find a suitable candidate. Max HP I've measured with an Eiffel club is 38 HP at 5600 RPM using a 1.8 belt drive. Total weight minus prop is around 73 lbs with oil. When my Badland kit eventually arrives, I'll be using the AIXRO XP-40 rotary engine I already have downstairs, so the Briggs was just a fun project. At some point I'll sell the Briggs if I don't find something to put it on soon. I'm not quite done playing with it though.

Rusty

Rusty, do you by chance have any select links to information about the Briggs? I'm talking with Chris now about using it. Also looking at other options. That rotary is going to have one heck of a reduction isn't it?

Todd

[13brv3]

Rusty, do you by chance have any select links to information about the Briggs? I'm talking with Chris now about using it. Also looking at other options. That rotary is going to have one heck of a reduction isn't it?

Todd

Hi Todd,

I've got a thread running on the Homebuilt Aircraft forum about it. You can also find videos and info from Leonard the Legal Eagle guy.
https://www.homebuiltairplanes.com/foru ... ine.49793/

The engine made just over 40 HP today at 5680 RPM, which is pretty amazing. There are still some concerns over how well it will cool without the fan and shrouds, though they seem to work fine for the Legal Eagle guys, and others. The other concern is vibration.

The AIXRO has two options for PSRU ratio, 2.5 and 3. I chose 2.5. Max RPM on the aircraft version is only around 7000 to allow it to run full throttle longer. The Kart versions go much higher.

[Badland-F5 Pilot]

Rusty, do you by chance have any select links to information about the Briggs? I'm talking with Chris now about using it. Also looking at other options. That rotary is going to have one heck of a reduction isn't it?

Todd

Hi Todd,

I've got a thread running on the Homebuilt Aircraft forum about it. You can also find videos and info from Leonard the Legal Eagle guy.
https://www.homebuiltairplanes.com/foru ... ine.49793/

The engine made just over 40 HP today at 5680 RPM, which is pretty amazing. There are still some concerns over how well it will cool without the fan and shrouds, though they seem to work fine for the Legal Eagle guys, and others. The other concern is vibration.

The AIXRO has two options for PSRU ratio, 2.5 and 3. I chose 2.5. Max RPM on the aircraft version is only around 7000 to allow it to run full throttle longer. The Kart versions go much higher.

Thanks for the info and link. I'm on Homebuilt but haven't logged into it for some time. I guess I need to do that, might help! At 40hp, that would be plenty acceptable. Of course, I'd love the 50hp from the F-23, but if I want 4 stroke, I'm going to have to give up a few things. I think the Thump Air also has a mild vibration issue, but only at idle. Talking to Scott, he's working on a damper or some other method to reduce the idle vibration. Thanks again for the info and link.

Todd

[Kevin]

Question. Tom Hail has quite a few videos of a Badlands flying with good performance. Does anyone know what engine he is flying behind?

Thanks!

[13brv3]

Question. Tom Hail has quite a few videos of a Badlands flying with good performance. Does anyone know what engine he is flying behind?

Thanks!

That would be the ThumpAir460 that Badland lists on their engine section.
Rusty

[Badland-F5 Pilot]

I have spoken to Chris recently and to Scott sometime back. My concern was the TBO. Scott said the problem with determining the TBO is that they just don't have enough hours on the engine. He did say that he expected it to go to 500 hours or beyond. If I remember correctly, Chris said they've got over 30 hours on the engine, but more time on the engine is needed for validation of all components.