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A084  4-stroke engines  This thread currently has 7,002 views. Print
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Kurt1600R
May 18, 2014, 10:02pm Report to Moderator

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Anyone have any interest in Teledyne A084 engines?  I think I have a lead on where I can pick up some.  I think I'm going to take 2 of them.  I think
they might be great on a MiniMax project.  They have a real aircraft engine sound and produce about 40 hp, I think.  Cost would be $400 to $500 ea.
plus freight to where ever you are.  From what I've heard, they are getting harder to find.  I think my connection has about a dozen of them.
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The Termite
May 18, 2014, 10:15pm Report to Moderator
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If you can get them "surplus new,  in original gov crate" for $400-$500,  that's a really good price.  I believe Harless Greer has one on his Himax, using a redrive.

I bought one to install on my Himax, but I haven't done it because it would mean completely re-doing the front of the plane.  And they are heavy, compared to a 447/503 or Hirth.
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pkoszegi
May 19, 2014, 7:32pm Report to Moderator

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I just overhauled one, works great on the bench. Its currently with the exhaust workshop, sorting out some exhaust before the brake in procedure. At the weekend I am going to buy a Himax which has a 084 engine.
I bought one from Bob, he gave me very good support, also I am talking to Harless about his developments. But I believe I am going to have the second Himax which a 084 and I hope I can tell you good things.
Its gonna be a direct drive, and however I am kinda electric starter, redrive person I am convinced that direct and prop start can make this engine as one of the top choice for Himax.
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pkoszegi
May 24, 2014, 7:44pm Report to Moderator

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Here we go.
I bought this.  I flew about 10 minutes with this plane and its a sheer joy. The sound of the engine is awesome. In my 30 years of flying never ever heard better sound.
Its weared out, the engine is ready for overhaul (but I have one I can swap within a day) but it still flyes well.

084 is definately a good option. Am I the second one on this board who ownes one ?

It came with a starter, the previous owner put a Skoda Favorit starter on it with a relative large flywheel. I dont know if this original or home made.
Cranks well. No carb heat box, but all intake tubes are insulated with foam and the carb is breathing from over the exhaust from the engine compartment.
I find no issue with the weight, it glides better than my 582 powered minimax.

On the 084 pretty much everything is as it came off from the original generator, and the prop is direct drive.
I cant tell you too much of a flight experience, I am straighten things out what the former owner disregarded. (loose rudder and tailwheel wires, wrong wheels e.t.c.
But even with abuse like this it flies very very well.





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pkoszegi
May 24, 2014, 7:45pm Report to Moderator

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some more



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aeronut
May 24, 2014, 8:55pm Report to Moderator

blue sky and tail winds to everyone
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WOW that is really cool. I bet you could put it on u-tub so we could hear it go.  


never surrender; never give-up
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srbell
May 25, 2014, 2:31am Report to Moderator

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Nice looking Hi-Max!  Sounds like the 084 is a good choice for them.



Scott Bell
PP ASEL
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Kurt1600R
May 25, 2014, 2:41am Report to Moderator

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Thanks for the post pkoszegi !!  Great pics!  Looks like a nice airplane!  I bet it does sound great!!
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samiam
May 25, 2014, 3:16pm Report to Moderator
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Thanks for posting this! I am very interested in this engine but wanted to see some good performance data behind it. After you fly it around a bit, could you let us know what your performance is like?

I would love to rebuild my own engine instead of just buying a hirth and hanging it up front, but would like to see some successes with it before I went that route.
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pkoszegi
May 26, 2014, 6:07am Report to Moderator

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Tom, I dont know what will happen to the valves, but the sound is really loud with no or with short exhaust pipe.
If you put short exhaust and no flywheel, no generator, no starter, no oil filter, you will end up just under 62 kgs 135 lb dry. Which is exactly the same as a 582 rotax with all bits and pieces. Its 13 kg more than a 503. and 18 kg more than a 2702.
The wonder is that it need no tuning, no changing carb, no nothing, but a hub at the front.

That exhaust underneath might save a few pounds but the sound of this engine,   - mate , - I can tell you thats the music of the spheres.  When the previous owner cranked the engine for two of us first time , we looked each other and said the same time: F.... THAT IS THE the sound...
Pictures taken from the replacement engine I bought from Bob, by Bob. Published by courtesy of Hoskins Engine Laboratories



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pkoszegi
May 27, 2014, 8:36pm Report to Moderator

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Some prop info for the record:
Bob and Harless recommend 54x27 props from Tennessee props. According to my calculation I have a 59x20 inch currently on it flies well with it for years. Max static RPM is 2850 which is far from the ideal 3200-3300, but definately does not overspin the engine. I ve tested on the overhauled engine an other prop which is 55x22 which spins 2950 on that engine. This prop is designed for 447 trike with 2:58 redrive.
Just ideas what sort of props on direct drive makes a Himax fly.
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pkoszegi
June 1, 2014, 7:15pm Report to Moderator

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Here we go with the 4a084 engine sound video.

https://www.youtube.com/watch?v=KjS_6tcvAuw&feature=youtu.be

More will come...
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aeronut
June 1, 2014, 8:12pm Report to Moderator

blue sky and tail winds to everyone
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Yes that really sounds good. Thanks for letting us hear it. Blue sky's and tail winds to you.


never surrender; never give-up
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JonF
June 2, 2014, 2:35am Report to Moderator

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That sure is a nice sounding motor!!!  I want one too.


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pkoszegi
June 2, 2014, 4:34am Report to Moderator

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Quoted from TreeTopsTom
That sounds GREAT!!!!  Way COOL!!!!
Plus as you said, The fact that it is possible to just put a hub adapter on it and it's ready to go!
I have heard those engines were build like , as they say, "a brick shit house".
Guess it's probably true. BUTTTTT
Has anyone torn one down after (X) hours to examine (measure) thrust bearing wear?
And would it really be a critical (instantaneous) issue or would there be plenty of warning of it's wearing out condition? Obviously these engines were meant to turn a pulley so I have to imagine there design did not take into consideration a constant (pulling forward) load. I would think this would be something to be aware of as the hours of use add up? yes? NO? I also imagine that a redrive would solve for that issue if you are skilled enough to fit one. (I know I'm not). But I think I would rather take my chances with that 4 stoker A084 out front than my 2 stroke Zenoah G-50. But the weight!  Must make for a good dive bomber...LOL                                                                                                  TTT


Tom, this engine is sound like hell as I saw it when I had my spare one completly overhauled.The work here cost around USD 400 + spare parts but they replace all bearings, piston, rings, rods and valves if needed. I paid USD 250 for the stainless steel exhaust.
The weight is not that serious. 125 lb is the weight of a 582. You may balance the difference of a 503 vs 084 with a good size of battery half way in the fuselage.
What I heard that these engines are there to run for 1000 hours + without any sort of problem over 3000 rpm constantly.
If thats true, this is the only engine which have a proven record of this.
The engine can provide 200lb of static thrust for sure (Bob has a video of 230 lb on a direct drive with 54x27 Tennessee prop). The Hirth 2702 provides about the same with 2.58 redrive, and 160 cm 3 blade composite prop. And look at my other video of my other Himax taking off and landing in 200 ft. Thats  20 kgs or 44 lb difference.
The engine with direct drive is really enough to power a Himax.
I am a lucky guy being only 73 kgs 170 cm tall (160lb 5.6 ft). So if you guys are around the same it should not be a problem. The problem would start with over 200 lb and over 6 feet people.

Well there is an option of a sincle cylinder two stroke 19 kg (45 lb) Pollini thor 250cc 36HP engine for EUR 4500. But is that what we are looking for  ???

Just the low cost of the engine, overhaul, operation and the cheap wooden two blader prop makes sense for me. Not to mention the less than consumption of less than 2 Gal/h ?


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Bob Hoskins
June 2, 2014, 6:27pm Report to Moderator

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Hi All & TTT;
Just for information. The A084 has a 1500 hour TBO. The center main bearing has a substantial thrust bearing. It can be thrust in both directions. This and the other Armed Service Standard Engines were manufactures to do almost anything, LOL and stay running at 3600 RPM doing it. Parts are still cheap, but will not last forever. Engines are getting more expensive because there were 3 million built and they are gone? Probably horders got them, LOL. All I can say is it is a darn good engine and it flys a Max very well. I have one ready to bolt right on my 1400, but that is now for sale.
Harless has flown the pants off his with over 500 hours on the engine and over 100 with my re-drive. Peter, get going, you have to catch up to Harless, LOL.
Bob



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Fly safe and have fun.
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Bob Hoskins
June 3, 2014, 4:19pm Report to Moderator

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Hey Guys;
Talked to Harless this morning and I was wrong about the hours on his engine. He has over 300 hours on it not 500.
Bob


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pkoszegi
June 3, 2014, 7:36pm Report to Moderator

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Today was wonderful, so I went to explore the new max. I did a few takeoff and landings. And a little x country.
Well, it needs a 150 m (450 ft roll) to rotate for takeoff, and with me it climbs 2 m/sec (400 ft/min). Its not a STOL for sure. Our grass strip is around 1500 Ft, its not particularly a challenge with that sort of runway. Landing could be done within 300 ft, it flares but not too much. Since I dont have tach I just feel that the maximum rpm is around 2850 and for cruising I guesstimate around 2600 for 110 km/h (70mph) . Best climb rate is around 85-90 km/h. The funny thing is that little over half power (guessing of 2200 rpm) it cruises 100 km/h (63 mph).  It does 120-125km/h  on full powerVery pleasant cruising in a non turbulent weather.  Consumption goes around 2 GAL/h but I made several takeoff, climb, descend.
The oil stays on 65 C - 150 F, Cyl head on 150 C - 300F all the time. Looks very stable.

Landing is smooth, I dont feel it would want to dive like a rock, but the weight does definately takes its toll.
I have a glass fiber landing gear with a small tyre on it but its like a Cadillac. Very soft landings with no jumps. I think that the whole structure appreciates any sort of cushioning with such a weight involved in the gravity play.
I got some more props, tomorrow I will have some more testing with different props.
I would compare this to a loaded C172, maybe a C150 with two person and full fuel on board. Same feeling, you dont really want to get into very turbulent weather with that one either.
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Bob Hoskins
June 4, 2014, 4:35pm Report to Moderator

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TTT
That is my engine in the pictures, but Harless's looks just like it. There are no CNC files for the re-drive. Both of them are "hand made", lol by me. A machinist, a dying breed today. I will help anybody that wants it. I have drawings of the parts for the re-drive, but it is complicated, LOL. There is a company somewhere out west that makes a re-drive for the 084 for about 8-9 hundred bucks. I have the link somewhere on this PC if interested. I have not flown behind a 084, but the one you see in the picture is ready to bolt to my Himax. It is a complete firewall forward. But I have the Himax up for sale now.
Harless is the guy to ask about performance. He is the "test facility", LOL. He is testing the engine and the re-drive. He has flown it straight drive and reduction. The ratio by the way is 1 to 1.666666666666666666666666. Sorry, LOL that is just the way it worked out. So, any questions about the engine and parts, ask me. Questions about the engine AND flying, ask Harless.  
Also, don't forget Peter. He is going to have a "fleet" of Max's soon. He will be doing a lot of flying and prop tests with his. So there will be good info out there for the asking.
Bob


Fly safe and have fun.
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Harless Greear
June 4, 2014, 6:47pm Report to Moderator

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PSRU for the 084 can be bought at:       http://www.arrowprop.com/rdrive.htm


HARLESS in Va.
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Harless Greear
June 4, 2014, 6:47pm Report to Moderator

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PSRU for the 084 can be bought at:       http://www.arrowprop.com/rdrive.htm


HARLESS in Va.
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Bob Hoskins
June 4, 2014, 8:28pm Report to Moderator

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That's the one Harless, thanks.
Bob


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pkoszegi
June 5, 2014, 7:11am Report to Moderator

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Tom:
I cross referenced some props with the overhauled engine (on the test bench) and the one in the plane which shows less compression. The top RPM of the prop differs only by 50 rpm or so which is not a lot. So the engine I have and have at least 180 hours in it, looks good as the new. It was told that it was new when the owner installed it. I doubt that though.
So just repeating : with 2850 static RPM it produces already enough power for takeoff on direct drive. Estimated 55x22 prop can get you good cruise, 450 ft to rotate takeoff.  
Now if you want to invest into more weight and more parts to fail that is still a question for me too. Do you really want to pay for a redrive as much as your engine cost ?

Other important but not related to 084:   FUEL HOSE  issue:

I refuelled the aircraft yesterday, and I must admit I dont like the current setup for fuel tank. Its behind the seat, but a long thick tube goes up to wing level. When I fuel I dont see any sort of fuel level indication, so the fuel spilled into the cabin. Right onto the seat foams. It was soaked but the fuel did not go anywhere else so it can dry out.  Not a big deal just ruined my day for flying.  I took the seat out and look at the petrol tank first time. Down at the bottom where fuel line starts right on the tank output the petrol fuel line is melting like a chewing gum. So it was a nice accident to discover that.
I am sure that there is nothing wrong with the fuel rated hose, but more about ethanol what the govt allow in any fuel up to 5% without any notice to public.
Check your fuel lines in every 25 hours or so from the tank to the fuel pump because this is a regular problem. I had that with the other Himax too on the 2702 engine. After a winter, storaged in a dry cool place (hanger) last spring it showed cracks in the middle.
Or fuel rated hoses are not fuel rated anymore however its labelled like that.
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Harless Greear
June 5, 2014, 2:26pm Report to Moderator

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TTT, I think you would be better off buying one from Arrowprop.. The one I have is second to none for quality and it also has an extra bearing in the center of the crank pulley to help keep  the belt tension load off of the crank.. I would guess that if you get one made like mine, it would cost more than twice as much as the one from Arrowprop.. I don't know anything about the quality of the Arrowprop.. You might could call them and get to talk to someone that has one..

I would negotiate with Bob, I think it's freshly overhauled and has engine mounts already on it.


HARLESS in Va.
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Bob Hoskins
June 5, 2014, 2:33pm Report to Moderator

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Hi Peter;
I strongly recommend you don't use any fuel with any amount of alcohol in it. They were designed and built in the 60's. there was no alcohol in any fuel back then. I don't know if the rubber products in the engine will take alcohol.  The same with the fuel lines. VERY dangerous. They swell up and choke off the fuel flow, the first indication is just like you found, chewing gum. Here in the states, we have some gas stations that sell ethanol free gas. Sometimes it is premium. If all you can find is premium, advance the ignition a couple degrees to help compensate for the slower burning fuel. Remember to use Marvel Mystery oil. 2 oz/5 gal. Our auto gas has NO lead, so we have to lube the top end. Sorry for using a "brand" name here, but I have been using it with old design engines for 30 years and have not had top end problems.


Fly safe and have fun.
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Bob Hoskins
June 5, 2014, 2:53pm Report to Moderator

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Tom;
Lets see, where do I start? All my drawings are CAD drawings. No, I have not seen the other up close an touch it. Your local machine shop probably would not make it for you. He would know by looking at it he would have to charge you $4000.00 for it. It all comes down to hours. Harless and I are good friends, and you don't count hours when you help a friend. So, your machine shop would definitely be counting hours. If you check on re-drives, you will see that even the simple ones are $1,200.00 or more. So $700.00 seems to be a bargain to me.


Just a BIG note and warning here!!!!!!!!
These A084 engines you find for sale, are run out ready for overhaul. Read that again so you understand. The US Govt. fazed them out so all their equipment would run on the same fuel. A very smart move. So, as the engine ran up the time they removed them and put them up for auction. The only way to get one ready to run is buy an overhauled one from a trusted source, or buy a new one. Rebuilts and new are still available. NOW, when I say run out, I mean they are ready for new bearings rings possible valve work and so on. The cranks are hardened steel as with the cylinders. The Babbitt on the bearing shells has worn and any further running will destroy the cranks. Yup, good oil pressure, yup good compression, yup i destroyed my engine. If you buy one, just go ahead and buy the parts and overhaul it before you get in trouble 2500 feet up. The parts are dirt cheap, it would be silly not to make it good as new.
Bob


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Bob Hoskins
June 5, 2014, 3:29pm Report to Moderator

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Tom;
I think you asked if I would sell my engine (A084). Since I am selling my Himax, I guess I would consider selling the engine. I will post it in the for sale section.
Bob


Fly safe and have fun.
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pkoszegi
June 5, 2014, 8:42pm Report to Moderator

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Quoted from Bob Hoskins
Hi Peter;
I strongly recommend you don't use any fuel with any amount of alcohol in it......... Sometimes it is premium. If all you can find is premium, advance the ignition a couple degrees to help compensate for the slower burning fuel. ...........Sorry for using a "brand" name here, but I have been using it with old design engines for 30 years and have not had top end problems.


Bob, its not a choice here. You dont know what you get when buying 95 unleded. There is no such a thing here that free from ethanol guaranteed.  Than we dont have marvel mistery here either. Liqui Moly or Metabond is two major additive supplier, I can have a look at them what they have.
So pick an other brand and suggest what to use .
I am all ears !

But it is a sheer joy ! I flew an hour today, made some vids , but will publish later.
Better than a two stroke for sure,even in direct drive.  

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Bob Hoskins
June 5, 2014, 10:15pm Report to Moderator

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Tom;
No that info was not gained by personal experience, LOL. There seems to be a standard where people compare this engine to the old VW. They are two completely different engines. The VW is generally 1600 cc's where as the 084 is 1378cc's The vw can be made to 2300cc's the 084 stays at 1378. But, in that 300 or so cc difference the 084 is 40 pounds lighter. The 084 is just a smaller engine capable of just so much. It will fly a minimax, it will not fly a 2 place plane.

Peter;
I did not realize your fuel problems over there. The engine is pretty much safe from the alcohol. There is an O ring on the main jet in the carb that can be swapped out to Viton. The needle and seat in the carb are stainless steel. The rest of the engine seals are in the oil so no problem there. The main thing is the fuel tank and fuel lines. There is fuel line you can order from Ac/Sp that is safe with alcohol fuel. If your fuel has no lead you should find something to add to it for top end  lube. I would not look for a lead substitute. Just a thought here. Skyblazer and I use Bluemax oil in our Hirth engines. We are supposed to mix it at 100 to one. It does not smoke, you can't tell it is there. I bet if you used 2 or 3 oz of that oil or something like it per 5 gal gas you would be safe. I know I have drained old fuel from my max and put it in my fuel injected car with no problems at all. Something to think about any way Peter. Hey, when you going to post your videos?
Bob


Fly safe and have fun.
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pkoszegi
June 6, 2014, 5:41am Report to Moderator

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I looked at petrol additives, there are so many that is hard to choose from. Some of the old timer guys suggest to use transmission oil (ATF).
I dont want to build up more carbon there, rather clean it and at the same time get more lubrication.
I am thinking of two stroke full synt oil also in more than well over 100 mix. Which is exactly what you suggest.

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