LEXL Engine Option Discussions 1/2VW, Verner 3V, BSV23 and BSV35

Some comments regarding the various engines I have tested on Legal Eagle XL ORV. This includes the Hummel engines 45 hp 1/2VW, Verner 3V 3 cylinder radial, BSV23 (Briggs and Stratton Vanguard 23) and the BSV35, (Briggs and Stratton Vanguard 35). It should be noted the lighter a flying machine is, the more fun it is to fly. I have some time with a 60 hp full case VW on the Legal Eagle XL, very smooth operation but very heavy. I am only showing total weight of engines as I have been involved with. This includes engine, prop. prop bolts, engine mount bolts, engine mounts, exhaust pipes, oil tanks, hoses, carbs, batteries and anything else related to engine for a flying machine. The 1/2VW is a hand prop engine, it is very easy to do standing to side of machine and behind prop. When engine starts it pulls the machine away from you.
Engines with Starters are very nice for a variety of reasons. From an over all fun engine the BSV23 is difficult to beat. Easy starting, and no dripping oil out exhaust pipes or having to do anything special before starting. This engine has two magnetos, one for each cylinder and they do not required power to keep operating, just a ground to stop engine. The Verner 3V is my favorite with 42 hp at 2500 rpm, designed for aircraft usage, cruises with max gross weight at 2100 rpm at 2.1 GPH. Three cylinders with one CDI for each cylinder. If you do hot have power engine is not operating, generator power battery, battery powers CDI's. The 42 or 45 hp 1/2VW is a great engine with lots of them attached to aircraft. This engine generally comes with a magneto or 009 point type ignition (one used on automotive applications) as well as other types of ignition. The magneto provides spark as long as engine is operating so fuel is determining factor in flight duration. I cruised at 2800 to 2900 rpm at 2.4 GPH.
Regarding engine choices, it is very important to know what your flying objective is. Some people enjoy building but not so much the flying. Some people do not like the building but really enjoy flying. Some People only care about being in the air, not going anywhere in a hurry, just flying. Some people want to squeeze every ounce of power and performance out of engine and prop. Knowing where you fit and what you want to achieve as final product to enjoy is very important to understand. The LEXL is not a fast machine on best of days but it sure is fun just flying.
The average no wind cross country speed you see on GPS is 48 to 50 mph. My record with tail wind is 86 mph and with headwind is 18 mph.

[JeffCurtisIflyHG]

I have the plans, I'll be building a LEU (I weigh 140Lbs), I'm at sea level, and I will be using the B&S 23. It is part of my overall plan to build light. Thanks for all the development work on this engine.

[brianbuckley]

I appreciate your story on the engines for ultralights. I had to make this choice recently but I went with a Generac 990cc vtwin. I don’t regret it at all. A fellow EAA member went 1/2 VW and has broken the crank snout twice in his Hummel bird and is waiting again (6-11) months for repairs. I did have to by a early model case half and a prop speed reduction unit. But it’s still cheaper and these motors are made to run hours at 3600 rpm. No cast iron crank hub to be welded on the crank snout.

[keithschneider]

Good comment on the options.The Difference of them.

[nattybumpo]

Thanks Les.
Ordered a 45 hp full case with the 2220 slick today from Scott Casler.
Building my xl as we speak.
I really want that Verner, but its just out of reach financially.

[harpandharley]

Great comparison Les! You addressed the strengths and weaknesses clearly on all three engines. Leonard and I are working on his original LE before I bring it home and I am going to stick with the better-half VW. It doesn't have the same horsepower (30) but it's very reliable and easy to hand prop. I'll add a wind generator soon to solve the battery charging issue and it will still be under 254 pounds. Keep up the wonderful videos!

[terrylutke]

Vanguard 23 is one of the sweetest V-2 air cooled engines out there. It's about 75lb out of the box and responds well to light hotrod mods. Best-bang mod is a Mikuni style carb, or twin carbs if you don't mind 2 carb hassles. I've flown them with cams, rev kits, and an advance ignition key. Lot's of sporty aftermarket parts available. These will make 30hp++ with pretty modest tweaks. I'd avoid the pricey billet rods, flywheel and other doodads, keep it economical and simple.

[apfelsnutz]

Thanks Les, a very informative, excellent video. Too bad you've moved so far away out of Ca. ...I never did get time to fly over and talk. All the Best and thanks again, Ron

[stanRmeyer]

Excellent job on comparison thank you so much! Could you give a rough approximation of the sum total $ for the small BS, pair of Mikuni carbs, redrive and prop.

[vgair]

the briggs engines are engineered BEYOND all other engines you mention with regard to tolerances, they use state of the art automotive CNC and automated production on all vanguard commercial engines, thats why they are 1, 000 dollars more than the competitors engines like the predator. The 23 has produced 70 and 98 hp in competition builds

[waynegilchrist]

Thanks Les for the update. I wanted to build my own half vw but you have to modify and fab so much that was out of my wheelhouse. And are these plans going to be drawn up nicely or are they just sketches I've run into before? Thanks and keep up the good work!

[Jack-nevm]

Vibration comparison? Phones have a vibration app that might put numbers to what you feel..

[TheeAthis]

Great review and information. Some friendly advice, do yourself a favor and purchase a 1 inch wide Velcro cinch strap belt (belt has the plastic loop thru buckle) and replace that zip tie on the battery. They're inexpensive, more robust and handle vibration better than the plastic zip tie. Blue Skies!

[tomster]

Les, how do you feel about the 2 Cycle Hirth 23?

[chuckstottlemyer]

Hi, Les.. I'm getting less and less enamored of the S&S clone carb on the Verner 3VL. What carb have you settled on with your 3V?

[BrokenFarmer]

Thanks for this Les. Are you going to have plans or genera advice for the BS35?

[utuberagain]

Les, you started with the 45hp half VW and ran that 450 hours, correct? Why did you change it out for another engine? Was it just to try something different or maybe some issues/problems with the VW? 450 hours on one sounds like quite a bit of flying.
Thanks for creating and posting such informative and interesting videos.

[vgair]

well, the briggs 23 doesnt have dual ignition.. BUT IT CAN, now, 2024, carrier performance has a new head SPECIFICALLY designed for the EU aviation community, it is drilled for one plug but has provisions for a SECOND plug in each cylinder, that second plug can be drilled and tapped by Carrier on order, it also flows much better than a stock head, 800 bare or 1700 built.

[timyandow]

Is there a guide somewhere for converting those bsv engines? I think that would be fun to do. Especially if someone sold an add-on type kit for the mod.

[Yellow_cub]

Les, do you think you could mount a zenith carb with the BSV 23?

[AzebenIaBeite]

Hello, do you have a way to change the capacitor to 2?