ETLB Squawk Forums — Archive

Hi
I'm always looking/reading/researching the internet for small engine choices for aircraft such as the Mini Max line, one of which I am now building and should complete this year.  I have a 37 horse fully rebuilt Global but I believe I have sold it, which again allows me to see if there is a really appropriate "other" choice of engines out there.  My Max, like most, will not make legal u/l weight, even though I will pretend it does.  The half vw world is great in my book, so I am/was considering getting a new 45 hp from Cassler.  That choice puts me easily at the $5000+ point and I am not 100% sure yet that such a decision is the best one I can make.  I've seen everything from one or two people doing direct drive Subarus to those on the other end of the spectrum with 277s.  I want to try to stay with a four cycle if possible.  Anyone want to chime in with their thoughts on the Mini Max engine choice world bearing in mind my wish to stay as economical as possible on the acquisition and general preference for four cycle?  All comments appreciated as always.
Kim Brown
New Hampshire

Several of the local RV and Zenith builders used the Subaru. One RV9 crashed when the fuel injection rail ingested air and he didn't have enough altitude/time to purge it. The others sort of faded from the scene. They were somewhat expensive. One was an Eggenfeler conversion (the one that crashed) at about $22,000 One was an auto salvage yard  rebuild (the Zenith) at about $600 it also crashed but that was pilot error. One was replaced with an O320 and one was sold off.

Don't forget these engines also require a liquid cooling system which adds considerable weight, complexity and takes up cowling space. My suggestion is simpler and lighter is better. There is one 1/2 VW on the field (single seat Avid Flyer), one Model A Ford and one Corvair ( both Pietenpols ). I think the 1/2 VW is a good choice although it took several hours of flight testing and changes in the fuel system and magneto for him to get it right.

If you buy an engine from a supplier with a warrantee, put off the purchase until you absolutely need the engine. No point in having the warrantee run out while the crate sets on the shop floor.

I'm curious.....what's your motivation to sell the Global if you're considering another 1/2 VW? Is the extra 7 HP the temptation? Just for comparison, a LOT of Hummel Ultracruisers are built with the 37 HP Casler 1/2 VW as the go-to engine.

Lynn

My Max will probably be over 300 lbs, me and fuel another 250, making 550.  12/lbs/hp sounds better than 15/lbs/hp(rough numbers) and with something other than the Global I have the option of picking up electric start along the way.  And my decisions may not always be the most logical, sometimes I just do things to do something, and then try something else.  I picked up the Global first with nothing to mate it to , then got a deal on a complete Max so it seemed logical to marry the two.  I like the half vw family which helps.  I had a 37 horse Cassler on a Pup before I got the Global and the Max, in hindsight, I probably had as good as it gets with the Cassler Pup combo but failed to recognize it.
For me it is a hobby that entails changing things around, tinkering with them, fixing them up, selling them or trading them, I haven't figured out how to not drain my bank account along the way though.  I have enough years left for one or two more "somethings", likely candidates would be a Kitten or another Pup, last year I missed out on two Kitfox Lites, and one Kitten, wouldn't mind one more shot at either one of those.  Ah to dream..............anyway, seems as if the Global is going, I'll finish the Max this year I think, all the while thinking about and looking for engines, worst case, I have a Max with no engine but pick up a Kitten or Pup.  One never knows what will show up on Barnstormers or Craigslist.
Kim Brown
New Hampshire

Kim....Sounds like you have given this a lot of thought. I won't argue with what you've decided and hope you have fun while "going for it"! Best wishes.

Lynn

Right now I wish I was looking for a four cylinder VW as there seems to be some really good deals on Barnstormers, for $2500 or less, complete engines, obviously further info needed on each, but seems like opportunity for someone there.  Probably there are many four cylinder Maxes out there, I don't think I want to do that right now.  I used all info on this site to beef up the nose section of the Max to accommodate a half vw, not sure about going to the full vw.  Seems funny, I would be selling a half vw for what I could get a full vw for, I haven't fully digested that one yet.  Anyway, keep up the good work and comments.
Kim Brown
New Hampshire

Yes, there is a fair bit of work involved in modifying the crankcase and cutting the crankshaft down in such a way as to prevent it from becoming a glider engine. Every half VW that has flown in the UK has busted a crankshaft. How do you guys keep them in working order?

Unless you just can't stand the thought of a 2-stroke,  the Hirth F23 is 50 hp at 78 lbs weight, which includes electric start, belt drive reduction unit, and exhaust system. Flight plan for 3.5 - 4 gals/hr.

Retail price is $6591, but Andy Humphrey at Heavenbound Aviation can probably beat that price.

VW engine crank cases were designed for a specific task and manufactured as cheaply as possible provided that they could reliably perform that task.

My observed experience of people who've used VW engines in aircraft which have been modified for maximal power or low weight has been that it either ends in tears or high cost.

Hi
Responses:

The Hirth slightly wins for power over the 45hp vw
it also wins for weight
It loses for cost
It loses for its being two cycle
Net to me is it loses

Cut case versus full case vw
I would only do the full case reduced to two cylinder
the weight penalty in so doing is quite small with some complexity avoided along the way

Anyone found any four cycle snow machine engines from recent years of manufacture that would make any sense in the engine world?
Kim Brown


and you can bolt direct to the firewall without having to fabricate a mount

Gaokin 650  water cooled  v twin. A bit tall but stacks of power(53 HP), four stroke, 41 KG and dirt cheap. Available without a gearbox, fuel injected and electric start.

Quoted from tomshep Gaokin 650  water cooled  v twin. A bit tall but stacks of power(53 HP), four stroke, 41 KG and dirt cheap. Available without a gearbox, fuel injected and electric start.

How do you adapt it to an aircraft?  

My basic rule for aircraft engines is to use "popular choice" engines.  Engines get to be popular (Rotax, Hirth, Casler, etc.) by proving themselves in lots of installations over time.  Being the first one to use a new engine can be a crapshoot.

You wouldn't be   The redrive has been made and I am aware that it has been tested with a prop. Mounting is similar to a Luciole B&S setup.

Quoted from kfb Hi
Responses:

The Hirth slightly wins for power over the 45hp vw....

It loses for its being two cycle........

I wonder what the failure rate for Hirth F23 engines  vs 1/2 VW engines is........

And , the failure rate of properly assembled & maintained Rotax 503 DCDI (Prov 8 ) engines......

...minimal.

Kev Armstrong is now flying with this in a flexwing. Power and climb is excellent but it's heavy!

Sorry - posted wrong pic, that's a Briggs! I posted a pic of the Chinese engine a while back. Here's a Youtube vid of a test flight in a Trike though.  https://www.youtube.com/watch?.....57kyi57oclzxNhIB1dKo

..and very economical.

An acquaintance of mine who has retired from his regular job is now selling and brokering u/ls, sport pilot experimentals, an occasional engine, and I just noticed he had the four cylinder 4084 engine(not sure of the numbers)  This one has not been discussed on this site for some time although I know it was a few years back.  I don't know how to search for the past discussions on it.  Looks interesting, some issues that come to my mind would be parts availability, and the issue of no thrust bearing in the engine as it was designed for a different application.  Any comments on this one?  He was asking $950, his verbage suggested some work had been done on it to make it applicable to aircraft use.
Kim Brown
New Hampshire

While I joked about hirth in the past and my bad situation, hirth dominates the ppg market in two place ppgs

Quoted from 509 While I joked about hirth in the past and my bad situation, hirth dominates the ppg market in two place ppgs

I know a couple of A&Ps who say that Hirth has made huge improvements in the reliability of their engines in the last 15 yrs.  Andy Humphrey, who rebuilt my 377/447,  is both a Hirth and Rotax dealer, and he believes in Hirth.  He has a Hirth 3203 on his Quad City Challenger CH-2 clip wing. And, IMHO, his CH-2 is the finest one I've seen. ALL the "bells & whistles"....

https://www.youtube.com/watch?v=yEp9QTuoZE4

Also take a look at Valley Engineering. They have an adaptation of, I believe, the Briggs or Generac. They came up with a novel to smooth out the uneven power pulses from the V twin. Take a look just to see how they did it.

Kfb take a look at this ( kevin's mini max ultralight- teledyne engine) google it. It is a video. Using a fire wall for a full case 1/2 VW would be difficult cause your foot position would push the engine too far forward for good weight and balance. It probably could be done, but a bed mount would be much easier. I have no personal knowledge about the Teledyne engine but I do know of one individual that has a Hummel Bird in Maine and he has broken two crankshafts .

Here's the video(s) I think aeronaut was referring to.  https://www.youtube.com/watch?v=cj0hdymXfOg   and  https://www.youtube.com/watch?v=ppR5Boo7cn4

I had a 2A042 stripped and had a prop for it, but decided to go with a 277 on my MiniMAX. I ended up selling the '042 but still have some regrets about not using it. FWIW, you'll find various opinions about the HP potential of the '042, but I feel pretty comfortable about believing reports of them being about 24 HP in the real world. Spec rating is a LOT lower, but that was in very dismal military test conditions.

Lynn

What weight does a 2a042 come down to?

It's been several years ago, but as I recall my 2A042 weighed about 83#, similar to a 1/2 VW. I really can't recall if that included the prop but I don't think it did. I was of the opinion that I could have found about 2-3# weight to remove without any drastic measures. My understanding is that the oil pan weighed about 6#, but I never had mine off. If it is indeed that heavy a fabricated sheet aluminum pan (maybe about .040" or .060") could save a few pounds by itself.

FWIW, The prop I had was bought from Kevin, the fellow in the videos I posted. I don't recall the length and pitch for sure, but I believe it was about 54" X 20.  

Eighty pounds puts it well into 447 territory. Tweaking it to 30 Horsepower and using a better cowling would make for a lower drag max with frugal consumption at the expense of ROC. It would, however sound lovely and not bust crankshafts. Now, What can I get one shipped over here for?

Wonder if anybody has ever measured one up to find out if alloy VW barrels could be made to suit. The capacity could then be  brought up to around 60 cu in. and that would give around 35 HP with a decent carb and offset rocker arms.

Quoted from Max SSDR Kev Armstrong is now flying with this in a flexwing. Power and climb is excellent but it's heavy!

It might work on the beefed up V-Max frame.

Back in the dark ages ( 70's ) Bellanca built a Champ called the 7aca and the engine they used was a Franklin 2 cylinder horizontally opposed 4 cycle 60hp .  I have only seen one up close and personal and it was really hard to start. The Franklin line has been resurrected in North Carolina. The search I did not show the 2 cylinder back in production. I am somewhat computer challenged so maybe someone else  could look into it more thoroughly; if there is any interest.I think the engine model is 2A120.

The engine weighs about 152 pounds. A little heavy for a MiniMax.