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  • #46
    I can think of a couple of applications where the cost of a 915 would be worth it. I think you could take an early Lancair or Varieze and make a screaming high altitude x-country cruiser out of it. I did just check some prices on low time 0-200's. Pretty reasonable. I am pretty sure I will go for something on the lower end of the price spectrum if I do build an LSA. Plenty of options.


    • #47
      Hi Guys, my LSA is going to have the UL350IS. 130hp Fuel injected single lever all in at 175lbs (exhaust,charging system, starter etc included) . I’ve got a custom mount, cowl and nose bowl being built and the mount is going to move the engine forward 4”. As I’ve previously stated, I think the LSA is an incredible airplane and my personal favourite of the models. I’ve flown Marks a few times and find it hard to wipe the smile of my face. I can’t quite explain why but the performance and simplicity is addictive. Whether you like Rotax or not, the fact of the matter is that a Rotax FWF kit option will sell 50/1 better than an 0-200. And for the record, an 0-200 is more like 225lbs all in. My LSA should be airborne in the spring so looking forward to seeing the Data.


      • #48
        Like I said, lots of options for the LSA engine market. I wish the same could be said for 180-260 hp market. The UL engines are beautiful, also a bit expensive but they include a lot of stuff that Rotax does not standard. Maybe similar price to a Rotax, maybe a slightly better deal.

        EFI also requires an electrical system, probably at the minimum a bit under 30 pounds. Most folks want an electric starter anyway so that is a push for most.


        • #49
          Originally posted by svyolo View Post

          I am sure the 915 is probably a wonderful motor. Same with an IO-390. But they both also come with a wonderful price. That blows them both out of the water for me. I went with a Bob 540 for my 4 place kit, for 5 figures less than a 390.

          If I was going to build an LSA, and I just might, I might be tempted by the Aeromomentum motor. The LSA was meant for a 200 lb motor, and the AM13 and 15 are a lot less than a Rotax. I don't know what a rebuilt 0-200 costs, but there were a lot of them in C-150's.

          I don't have anything against Rotax motors. I think they have come a long way, and are very light and very reliable. I helped install a couple of them in ultralights about 20 years ago. The 100 hp 912 is hard to beat for a lot of LSA aircraft. I heard they have some going over 4000 hours between overhauls when used heavily.
          The 912 series has nothing whatsoever to do with the 2 strokes of 20 years ago. They shouldn't even be thought of as the same brand. One is a powersports engine and the other is 100% from day one an aircraft engine that is also certified just like a lycoming or continental.

          Agreed that they are getting way too expensive. An experimental overhauled 540 is cheaper than a 915.

          I'm a hard pass on the auto conversions since the gearbox, prop & engine combos go through no harmonic testing. At least I've not seen a single one that has. And lack of a failure is not indicative of no problem. Then when compared to the lyc/cont/rotax they have a few thousand hours on them vs millions upon millions on the other three.
          Last edited by zkelley2; 11-30-2019, 08:12 PM.


          • svyolo
            svyolo commented
            Editing a comment
            Not sure where the reference to 2 strokes came from. Both Rotax's I helped install were 914's, into a hang glider tug called a Dragonfly. Before that the tug's were powered by 2 strokes. The 914 didn't turn out to be a good tug engine. The tugs release the glider and dive down at idle to get on the ground as quickly as possible to tow again. They had shock cooling issues on a couple of cylinders in this application.

            Over time it became a very reliable and popular engine. Hopefully the UL Power engines will as well.

            Even better, I hope somebody comes up with something as good for half the price. Aeromomentum has several hundred engines in airboats. I am not buying one yet, but I hope they are successful.

        • #50
          I've been flying RANS S-7's for the last 20 some years, 3800 hours TT, and am still real happy with my current S-7S. The only thing to catch my eye the last year or so has been, the BH LSA. After being dragged kicking and screaming into the Rotax camp (I used a EA-81 Subaru conversion for my first bird, and it worked fine until I sold it at 1300 hours, but it was heavy, and for those that don't think an extra 30 pounds or so in the nose does). But on my second build, I opted for the 912S, and a while back reached the 2000 hour TBO with NO problems, and that was with my own modified maintenance, meaning I pretty much changed the oil and filter (Carquest filters) every 50 hours, didn't burn any av gas, changed the plugs about every 3 to 500 hours, had the gearbox tweaked once, and other wise just put gas in it and flew it.

          At about 1200 hours, I had Hal Stockman do the "low comp BigBore" kit on mine, bigger displacement but lower compression ratio, meaning at my 4 to 5 K field elevations I now burn REGULAR mogas until I get down to 2500', which is pretty hard to do in the areas I fly! That saves a lot of money, if you fly 150-200 hours a year like I do. Then I had him do the "1" crossover tube" mod, the stock 1/2" tube connecting the 2 intake manifolds is now 1". For reason I don't totally understand (and could care less) this makes for a very smooth running engine that now can happily idle at 1200 RPM. On a tight short landing, this beats coming in at 2000 r's. Then I put a HacMan Leaner on it, a simple and cheap aftermarket device that lets me play real airplane pilot and lean it out for max fuel economy, while still retaining the auto mix control as normal.

          Somewhere along the line, I put a 78" Prince P tip prop on it. Add all these changes up, and I LOST over 5 pounds (the Prince is lighter then even the lightweight Kiev I was using before and MUCH lighter then all the others, plus the BigBore, with it's CNC machined heads instead of cast, is lighter by 3 pounds. It also immediately dropped the CHT temps by about 30 degrees, due to better cooling fins, and more of them.

          All these mods result in me routinely turning in ridiculously low fuel burn rates. A typical 2 day XC up to Montana and back, maybe 8 hours, mostly at 80 mph ind. (5,000 rpm or so) while at 8500', averages 3.1 to 3.3 GPH. The performance is stellar, I have yet to see a Carbon Cub, as one example, take off or land shorter, though they do fly faster. I have 29" Airstreaks, and Cub style gear, though it is faired and covered. I see the cruise speeds for the LSA, very good, but I wonder what it would be with big tires and cub style gear. I am a big believer in cabanes, no other kind of gear spreads out the stress over the frame as well, it "pulls against itself", as one pilot commented recently. I happened to be at Mile Hi several years ago when Bob splatted his arrival, (he is a flatlander, no offense, and wasn't used to hill landings and their sight pictures) and took the gear out. Not a knock on the stock gear, for general use it's fine, and it's lower drag then cub style, just less stuff hanging out in the breeze, but it's not the ultimate in off airport like the John Roberts Avweld cub style gear I have. It uses bungees and airshocks to control the rebound.

          Back to the engine thing: The end result of the many mods is the noise level: besides being very low, it has a nice deep tone, I think it's the prop that is the main reason for that. Here's a link to a video we shot last winter, with some good sound to it, not your typical Rotax sound at all. I have zero interest in a O-200, just the oil consumption, on even a tight one, is a deal breaker, I am now a Rotax geek, big time. The UL's....get their rated power at too high of RPM's to swing a bigger prop for best STOL ops, and I'm not sure about the fleet hours they have built up, still a very small percentage of the 912 I'm pretty sure. Corvair, same deal as the UL, to high or R's and too heavy. I am also a major weight weenie, and am not at all interested in a 915 or even the FI 912, too complex and too heavy. IF I build again, I would use the same mild BigBore kit from Hal, along with the other mods I mentioned.

          I have a hard time with the LSA's lack of flaps. I like slipping, and do a lot of it, and I get the keeping it simple and light thing, but, I like my flaps! I've decided to NOT use my flaps for the next few landings, and just use slipping. It's wing has a lot more square footage then the S-7's 147 sqs., and I have no problem believing it's purported low landing speed and good climb, a big wing will do it every time.

          The main consideration for me in deciding on a BH LSA, is:how far would the nose need to be extended to make the much lighter 912S balance out? Would it look goofy, or could a CG shift be handled without a Pinocchio style nose? And, with 29" tires and also the extra drag of cub style gear, even fully faired like mine, what would the cruise be? I can take an educated guess on the second questionrobably about 15 mph. I do a lot of off airport flying, meaning no airport, mountain sides and peaks, places no one else has gone, at least to my knowledge so same thing. If the lack of flaps meant I couldn't get it down and stopped as short as my modified S-7S, I wouldn't build one. NOT only has no one yet put a 912S in the LSA, no one has put big tires on it and really worked off airport in "unknown" conditions, grass strip landings are not what I mean. The fuselage looks up to it, very robust, not too sure about the gear or the lack of flaps though.


          • svyolo
            svyolo commented
            Editing a comment
            My original impression of the 914 was it was very complex. Water cooled heads, air cooled cylinders, and a big oil cooler ( maybe because of the turbo). Our application has its' problems, and they weren't used for that very much, or for very long.

            I wish the 912S was a little less expensive, but a huge number of pilots buy it because it is worth it. I have nothing against it at all. When you start getting into the 914 and 915, wow the prices are pretty eye watering. I would have to really need the turbo for a specific reason for me to justify 32-38K for a small engine. But for some it is also worth it.

            It would be very easy to calculate how much to move the engine forward. It is not like replacing a 400 lb 0-540 with a 180 lb turboprop. Probably just a few inches would do it. I doubt it would be 6 inches. I think it would make a great BH LSA motor.

          • Mark Goldberg
            Mark Goldberg commented
            Editing a comment
            Just a short FYI. Bob's plane at mile high did not have the stock gear/shock struts. The shock struts did not have the snap rings holding in the bronze top cap. This is what failed when Bob plunked it down hard on that mountain top. So was not the stock gear. To my knowledge, there has never been a failure of a BH gear (on any of the models) when the plane was not ground looped. I think I did hear of one that failed but it was likely that the failure was caused by damage from a previous "incident".

            Your report of the years of use of your Rotax was interesting. Obvious to see why you like it. Mark

        • #51
          Great post, thankyou. I also would love to see a Rotax powered LSA but have opted for the UL on this one. I am putting big tires on it so should be some interesting results. I look forward to sharing my results


          • #52
            Great post, thankyou. I also would love to see a Rotax powered LSA but have opted for the UL on this one. I am putting big tires on it so should be some interesting results. I look forward to sharing


            • Cguy
              Cguy commented
              Editing a comment
              I just noticed you're the same guy with the great looking Patrol, whose video i just watched! Now I can put your comments into context, and judging by the way you have the Patrol setup, I am really interested to see your LSA when completed. Your's is the first I noticed with VG's, and I assume you'll use some on the LSA, that should be interesting. Crap weather here, but now have my Datum skis on and am ready for the winter! Hopefully you will post on your LSA progress, I am of course new to the site and still finding my around, and who's who.

          • #53
            Originally posted by Cguy View Post
            The main consideration for me in deciding on a BH LSA, is:how far would the nose need to be extended to make the much lighter 912S balance out? .
            This is Experimental aviation! Great post.

            Google says the 912S is 140 pounds while a Continental A65 is 167 pounds. The A65/75 was the original engine on Bob's LSA. It will do fine with a 200 pound engine, but the data suggests that there is an envelope and lighter engine do just fine.\

            I need the weight of the 912S that you'll be installing. If someone can get me the weight and the distance of the CG of the engine from the firewall or the Data at the leading edge, I can do the calculation to resolve the problem. My gut tells me it will be fine.
            Brooks Cone
            Southeast Michigan
            Patrol #303, Kit build


            • #54
              Hey, born and raised in Allen Park I was! My thinking was, I'd hate to have the baggage payload compromised, as in being unable to load more gear aft before, getting rearward on the CG, which is one good benefit of a heavier engine. I could see moving the engine forward as much as possible in the existing cowl, and maybe extending it a bit. EarthX battery on the firewall, goes without saying. I think the allup weight of a 912S with fluids and radiator would be very close to a A-65, close enough for guesstimate purposes anyway.

              What I really need to do, is slow fly and short land in the S-7S, along side a BH LSA, and if I got my butt whipped, that would push me over the edge in a hearbeat. I know it will be faster, no question. I've built 5 kitplanes (Kitfox1, built new wings and recovered a T-Craft, a Titan Tornado, an Avid Magnum (Which had an 0-320, which I ran out of gas once, being so far out of the loop as to how much more gas it used then I was used to) A RANS S-7, and the last 13 years the current S-7S. Before that a slew of ultralights (I was a Pterodactyl dealer), and before THAT a bunch of hang gliders. As happy as I remain with the RANS, I have the building bug, obviously.

              I have yet to kick the tires on one, lay eyes on one, much less see it fly, even more less, get to fly alongside one. I do remember a STOL event in Texas last year, and seeing a red one on some forum, that's it. My immediate plan is to get my Datum wheel skis on in the next few days, depending on my work schedule, and WX permitting, as I mentioned, fly my normal type places but NOT use the flaps just use slips to modify my glide slope etc.. Let me know if and when one will be in the vicinity of the mountain west, maybe this years CopperState fly-in?

              The T-Craft of course also had a big wing, glided real well, and no flaps. I remember getting checked out in it before ferrying it home. It's seller was a former ultralight pilot like myself, and as I had heard about the T's rep as a "floater", and "hard to land", I was very interested to see him make an approach so slow, much slower then I expected. A short rollout was the result, and when he got out the first thing he said was "that's right, it flies like a big ultralight!" I never forgot that and never tried to land before it was done flying, excess speed usually being the issue with most botched landings. My home runway BTW is 400' long, 5640' ASL, and sloped 12%. The 7 easily gets off and on it in less then half the available distance.


              • #55
                Define your mission.

                The 912 would have an engine mount built so that it's weight accommodates a very well balanced empty weight. The cowl is then custom built by mounting the nose bowl to the engine flange via a spacer. Then the cowl is built to connect the nose bowl to the firewall. So, the problem of trying to fit a 912 into a cowl set up for engine C65, or O-200 is totally eliminated.

                My sense is that Mark G. and Bob B. understand a 912 powered LSA could open up the market to a new sector of builder and want to work with that builder to make it happen.

                My second sense is that the Bearhawk product is a different mission than a Rans product. The S7 leans towards ultra light, the LSA leans towards a Cub. But I say that having no experience. I'm just building a Patrol and Not flying anything GA right now.

                Here is a thread about a comparison between the S7 and the Patrol. Post #2, #6 and #9 apply. Post #2 example has a fixed pitch prop. Those with a constant speed prop are all cruising faster.

                The Patrol is not that much more effort/money to build. Its a High speed STOL cruiser, huge 9 foot long flap that's 30% sq ft of an entire RV-14 wing.

                edit....I said not that much more money.....forgive me... a constant speed prop + governor + X/C instrument panel + Xpnder with ADSB + O-360 vs O-200 it all adds up to a lot of money.
                Last edited by Bcone1381; 12-02-2019, 06:12 PM. Reason: repentance
                Brooks Cone
                Southeast Michigan
                Patrol #303, Kit build


                • #56
                  CGUY - a friend went flying in my LSA along side a Rans S7. The two pilots are big buddies and have flown wingtip to wingtip for 30 years. The LSA took off shorter (a little) and climbed better (a lot). The LSA with an O200 was around 10 mph - 12 mph faster cruise. (It should not be faster with the added wing span and wing area. But it is.). The BH LSA stalled a little slower also which is to be expected with 30 more sq ft of wing area (even though it had no flaps). Both weighed about the same and had 100 HP engines. FYI. Mark


                  • #57
                    delete, double post


                    • #58
                      Originally posted by Clint B View Post
                      The prop was a Catto 78"X38" and it would turn 2390 static. It would do 90-93 IAS at 2400. I think you would want at least a 42 pitch if not a little more, as the LSA is so much cleaner.
                      My 78" Prince P tip is 48" pitch, and it's max rpm is 2390 (after doing the reduction gear math), most of my cruise flying is done at about 2000 rpm. These low rpms I think is one reason it's so quiet. I know that tells how much power my engine is producing, but I don't know the formula to put a hp number on it, it dynoed I'm told by Hal Stockman at 106-108, he also says a stock 912S is more like 92-94 hp.

                      I flew with a prototype Catto he sent me several years ago for testing, as he had yet to make an inroad with the Rotax crowd, and the results were underwhelming, less cruise and less climb. He still didn't have them dialed in for the 912. This was as compared to a Kiev 3 blade ground adjustable I was using at the time, plus the Kiev was lighter. Then I got the Prince and it was lightest of all and the best performance, especially "out of the hole." I taxi up a slope from my hangar to my launch site, and the Prince needs much less rpm then anything else.

                      Luga is a prop outfit in the Ukraine, and they make beautiful carbon adjustable props, 2 and 3 blade, any rotation. Buying from them you deal direct, not through a USA distributor or importer. It sounds like a scam, but you must Western Union (yes they still exist, PayPal or major credit cards NOT accepted only WU) 100% of the money upfront, and then wait! But, he (Roman) is legit and honest, and I have bought and resold many props from him. His pricing is so attractive, along with the high quality, it was a no brainer, BUT, the Prince beats even the Luga in performance, though twice the money. The 78" Luga I now have as a backup in case the Prince suffers a mishap (Prince took 6 months to get me my prop, he's busy) is as good in climb, but less thrust out of the hole, the same in cruise, but makes more noise and it's not a deep tone like the Prince has. I guess I'm firmly in the Prince prop camp.


                      • #59
                        Actual engine weight is always a hot topic. I know nothing about Rotax engines so how does this look? Seems to line up with what manufacurers were telling me when I was looking at LSA type planes; the said plan on 200lbs.

                        Components Weight, lb
                        Engine mount 12.2
                        Exhaust, muffler 6.2
                        Exhaust, pipes 3.8
                        Radiator 2.4
                        Heater hose, throttle cable, etc. 4.8
                        Mounting hardware, oil cooler and tank, water cooling components, air filter, miscellaneous parts 19
                        Total parts 48.4
                        Engine 0.8 gal 5.44
                        Oil tank 0.8 gal 5.44
                        Oil radiator, hoses 0.3 quarts (assumption) 0.51
                        Total oil 11.39
                        Cylinder heads, water pump, expansion tanks, coolant hose. 1.5 liters / 0.4 gallons as per Rotax installation manual. 3.3
                        Total coolant 3.3
                        Engine, dry 131.6
                        Total fwf, minus cowling 194.69
                        I’m a huge fan of Luscombes so I’m pretty familair with their engines. A non-electric A65 installation weighs very close to 185lbs installed ready to run. I really doubt there is any need to extend the engine mount for a 912 but a call to Bob would provide you a definitive answer. IDK, if he changed the mount length when he installed his C85.

                        You and I used to razz each other regularly when I was flying a Luscombe. I kinda miss rubbing you that my 100 year old tech engine/airplane was just as fast on the same fuel and didn’t burn a lick of oil. I think I need another airpane with a stroked C-85.

                        Honestly Tom, if your going to install cabane gear and always long for flaps then you should probly just stick with the Rans.
                        Scratch Built 4-place Bearhawk. Continental IO-360, 88" C203 McCauley prop.


                        • #60
                          Here is one item that should be considered . Four years ago when I was studying the prospect of where to position my 0-200 in my LSA scratch build the numbers on the plans did not add up. When trying to select the location for a lighter engine also note the prop, Bob had on his Cont. 65 with no elect. I don't remember the prop number but it was Alum. and heavy. What I am saying do lots of research before you spend your money. Stinger
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                          • svyolo
                            svyolo commented
                            Editing a comment
                            I know Rotax is severely limited by weight of the prop. So you can't help by adding a heavy prop. That might not be a Rotax thing, but a reduction gear problem. All the small gear engines look like they use pretty lightweight props.

                          • stinger
                            stinger commented
                            Editing a comment
                            Yes, I am trying to point out that all weight forward of the firewall must be considered and I also know that a Rotax can not handle a large heavy prop . Good Luck Stinger,Merry Christmas