There exist an 1/2 VW engine that was never cut in half, it had from the beginning only two cylinders, the DAF 44 or 66 engine. As far as I know, they never had a crankshaft failure.
Are you saying that the DAF44 car with its continually variable pulley-based gearbox used a VW engine as a base?
Can you point to any source of information on the DAF engines? Wiki says the early 1970s DAF66 used a Renault or a Renault-based engine.
In any case, aircraft need to use absolute full power for a period of time on every flight, but a car engine may get asked for full power only occasionally. The crankshaft of a car engine has an easier life.
Daf used their own engine for the flat twin models (Daffodil 750, 33 and 44.) A good and tough little lump, it has a massive and heavy crankshaft but responds well to tuning though you won't ever find one. It shares neither parts nor DNA with the VW engine. The 55 was fitted with an 1108cc Renault engine.
Larry Israel's flat twin was the Citroen engine from l'escargot d'etain (The tin snail, for the non French speakers.) It is high revving, has a one piece crank and rods assembly so bearings cannot be easily changed and even in 652cc form is pretty gutless. Add the necessary reduction drive and there is no longer any point. Works well in a 2CV but not much good as an aero engine. The French who have a big ultralight scene don't seem to use them and they are starting to become quite expensive as the 2CV and its derivatives have gained classic status.
Daf engines are their own and were never common. These days they are very rare indeed.
Hi There is a man on one of the Yahoo small engine sites who is always experimenting with different ideas of what engine to use and how to make it usable, or determining if it is not usable, and it is normally interesting reading when he does post something. I contacted him to see what he was working on and what he might have for sale that might work in my flat topped open Mini Max. I have posted his response below and am curious what most of you think about his v-twin that started as I guess 27 horse and might be souped up to mid 30s, and its suitability for my Max. Thanks Kim Brown] New Hampshire
My favorite 4 stroke engine to date is my Kohler CH27 with a stroker crank, an aluminum flywheel, a belt reduction drive, and dual CV type carbs. It generates about 36 hp and turns the same prop at the same rpm as my Rotax 377 dual carb. The Kohler needs no battery unless you want to use a starter. I put heavy duty valve springs in the Kohler so it is good for higher rpm. I believe the Kohler turns 4200 rpm with the 377 prop (UltraProp 3 blade). The Kohler engine is on my test stand and has not been started for 6 months. I would be happy to sell it for a reasonable price ( $2000 ?) My current project is an ultralight biplane (see Bloop ultralight) with a Paramotor 25hp engine.
I like the 36hp alternatives to the 1/2 VW. The Kohler Vtwin with stroker crank, or the Rotax 377 with gearbox. These engines are low cost and about the same weight as a 1/2 VW.
The Paramotor Vittorazi 185cc 25hp is a good package. There is also a 36 hp Paramotor for more money.
I once managed to get a Full VW down to 125#, but that was drastic. Still had the iron jugs tho, so might have been able to get it down more. essentially removed the flywheel and made an aluminum plug for the rear, made an aluminum prop hub, got rid of every single thing non-essential.
The original miniMAX configured as an ultralight. With 277 (also known as bullet proof in rotax family) in the nose will cruise 55mph that can reach 150miles distance in 5 gallon fuel tank. It is light weight and simple to operate. Only as lone occupant, I think its up for us pilots should learned to understand the beauty of this creature most likely it would fly low and slow. The fact, this is equivalent to 1/2A RC. Enjoy the flight!
I once managed to get a Full VW down to 125#, but that was drastic. Still had the iron jugs tho, so might have been able to get it down more. essentially removed the flywheel and made an aluminum plug for the rear, made an aluminum prop hub, got rid of every single thing non-essential.
how did you set thrust on the crankshaft? #3 bearing thrust?
Thrust on crank was simple. I kept the center part of the flywheel, but nothing more. it was still a 4cyl. essentially I plasma cut the flywheel part off the center, chucked it up in a lathe and smoothed it out some. You need the center section.
Thrust on crank was simple. I kept the center part of the flywheel, but nothing more. it was still a 4cyl. essentially I plasma cut the flywheel part off the center, chucked it up in a lathe and smoothed it out some. You need the center section.
Meaning that thrust is taken by #1 bearing as we are talking about 4 cylinder engine for V max .
Along with the Thor 250, there is an even lighter air cooled Thor 200. Polini offers a Tractor Mounting kit so these could be placed directly in the firewall or (similar short off set). Nice tight exhaust package as well, plus prop clutch.
Polini being the engine of choice now for BadlandAircraft and Belite Aircraft so there might be some promise over time for the 103 folks.
The Hent looks very nice, but, per the builder's Facebook page, there are no plans for production beyond the existing prototype. Says he wants to sell the design to a manufacturer.
If the Hent engine goes into production, it will probably be very expensive. It's essentially half of a Rotax 912. Other than the current lack of availability and likely high price, it would probably be great on a Mini-Max.
From what im reading besides being heavy and fast. Why would i not want to use my rotax 503 on my minimax 1100 with a beefed up firewall? (Note: May be an 1100 himax convesion... just finishing wing # 2)
I think your 503 would be ideal for a Minimax, or a Himax for that matter. In the UK we usually use the 447 and find that quite adequate, but then again, the UK is more or less nearly all less than about 1,500 ft above sea level. If you're based in the States in one of the areas that's higher than say 3,000 ft above sea level, then you may find that the 503 is the minimum you'd be able to get away with powerwise. There's not much difference between the 447 and 503 in weight, and the main difference from what I've seen is that the bolt holes for the mounting plate are slightly further apart on the 503, as it's got a longer crankcase. Other than that I don't think you'd need to do much in the way of beefing up of the area ahead of the firewall.
If it flies, floats or fornicates.... rent it! Flight Leader
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As Bob says. I'm just about to replace my 447 for a 503. It's 10lbs heavier, nominally. I'll post the difference details on here as I do it.
(don't hold your breath as I'm also making new wing attach brackets, moving the rudder pedals, installing a wing tank, doing a top overhaul on a Continental A65 for a pal etc.!).
Im at work right now... 65' above sea level. 52°f. I wanted to build a half vw and still might but the price is just too good and i dont want to pass on it. Sounds like im not making a terrible choice... (till the 2 stroke quits on climb out)
Just treat the 2 stroke right and you should be ok. However, make sure that the seals have been done and I'd probably send it out and have it gone thru anyway. Just be careful who you send it to. I sent one to the wrong chap once and got back an inferior engine.
The 503 is possibly the most reliable of all the Rotax 2 stroke family. Maintenance is everything of course but they are simple engines. Pay attention to the seals (as said) and make sure the rings don't stick in their grooves (50hr de-coke depending on oil used). If it's a dual ignition dual plug motor it's going to be reliable, watch your EGT's on climb out and you won't hear the sound of silence
The 503 is possibly the most reliable of all the Rotax 2 stroke family. Maintenance is everything of course but they are simple engines. Pay attention to the seals (as said) and make sure the rings don't stick in their grooves (50hr de-coke depending on oil used). If it's a dual ignition dual plug motor it's going to be reliable, watch your EGT's on climb out and you won't hear the sound of silence.
The Prov 8 503 is a really good engine. Properly cared for, it should last you a long time.
I use the NGK Iridium plugs, and either Citgo Mystik Sea & Snow semi-synthetic oil, or Lucas semi-synthetic oil. Adjust your mid-range jets as needed during the year for temperature changes, keep an eye on your EGTs, and warm your engine after cranking until the CHTs are over 200 F before T/O. Clean your carb air filter(s) frequently. Replace urethane fuel line at least every other year(including the pulse line), and re-build the fuel pump(diaphragm pump) every 2-4 yrs.
If storing for several weeks/months, plug the exhaust pipe and wrap the air cleaner with plastic wrap; this will help prevents air from moving thru the engine.
Something else: I run a custom fuel blend: 5 gals 100LL to 12.5 gals 88 octane non-ethanol. 2-stroke oil ratio is 50:1, using above mentioned oils. The approx 30% 100 LL stabilizes the fuel mix, boosts octane, and is not enough lead to increase plug fouling. It works for me, you may wish to use something else.
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