In all of the hundreds of posts that I have read, I have never heard anyone mention or talk about the FOX line of gasoline engines. Does anyone on here know anything about their 5.8 engine? How would it compare to the ZDZ80 at about the same price? Any and all comments would be appreciated. I need an engine for my big new 40% J-3 Cub.

The Fox line of gas engines are quality products. But the last time I checked, which has been some time now, the 5.8 hadn't been released. I don't believe that there are a lot of them out there yet to give any feed back one way or another. I have no doubts that they would perform well.

Don't know about the 5.8 Fox but I have been running there 3.2 motor for two years now with a couple hundred flights on it and it has been a flawless motor for me. I would not hesitate to buy another one.

Just my 2 cents worth.

Rich

Hi Jim,

I have a ZDZ80RV and a Brison 5.8 and I highly recommend both engines. Both will turn the same prop at close to the same RPM. The 5.8 may have a sleight edge.

I don't know much about the Fox 5.8 but it probably runs very well. They sure are proud of it because it's $145 more than the Brison.

One more consideration is the rear carb on the ZDZ80RV allowing a very clean engine installation. You also need to think about good cooling air flow across the engine. I wrote an article on baffling and it can be found here under the FAQ section. www.rcshowcase.com

Ken

http://www.brisonrcengines.com/ Brison 5.8 $579.95
http://foxmanufacturing.com/WOW.htm Fox 5.8 $725.00
http://www.rcshowcase.com/html/engines/zdz80.html ZDZ80RV $675.00

hey big bird, nice decathlon. read the thread last night. what is the weight difference between your two engines? this spring i will be buying either or. how does that zdz pull? does it have unlimited vertical or close to it? thanks.

According to the manufacturers specs the 5.8 weighs 6.0 # and the 80 weighs 4.2 #. These are bare engines. I had to add about 1/2 # to the nose of the Decathlon with the 80 up front.

My Decathlon weighs 32 # and just barely has unlimited vertical. To have sparkling vertical for a ZDZ80RV the plane needs to weigh about 24 #.

Ken

big bird, if you had a choice of which one to buy again, what would your choice be?

The ZDZ80RV for the Super Decathlon and the Brison 5.8 for the Ziroli Corsair.

the one i pick will be going in my 86" span ultimate profile bipe (3D machine). i'm hoping the weight will be between 20 and 22 lbs. i was also considering the First Place Engines 5.8, but didn't get alot of feedback about it.

Any of the single cylinder engines in that size range will have quite a bit of vibration in the lower rpm ranges. It can sometimes turn out to be quite a problem. You may want to consider a twin cylinder engine in a similar size to balance out the vibes. I'm a Brison driver all the way, but I think in this case a ZDZ twin would be the winner. Unless, of course, Brison has a twin in the same size range. They do have a very nice 6.4...

Thanks guys for all the very good responses. For those of you that have the ZDZ80, and the Brison 5.8 - will either of them swing a 27 x 8 prop? I have read many responses, and they all settle in on a 26 x 10 as the favorite. I'm thinking that the slightly larger dia. and reduced pitch would be better for a Cub. I called FOX and they told me that the max. they recommend was the 26 x 10. Also - the FOX 5.8 has electronic spark advance, whereas the Brison has mechanical linkages. Have these linkages ever been a problem?

A lot of years ago I sold Sachs-Dolmar engines with linkages, and when they screwed up and advanced the spark too far - it would take out the engine bearings. I like the idea of the electronic advance.

After checking out the Brison engine web-page, thanks to Big Bird, I now believe that the right engine for the airplane is the Brison 100cc twin at $995.00. It has the electronic spark advance, and sure sounds like a winner to me. (Silversurfer - yes - there is a Brison twin. I just found that out also).

Edited: I just answered my question about prop size. The ZDZ80 states that this engine will swing a 28 x 8 prop.

Jim, I believe you will like a 26x10 prop better than a 27x8 with that big 40% Cub. Any of the engines that you mentioned will spin the 27x8 with authority. However, the Cub will look like it is in low gear with the engine reving high. IMO the Cub at 40% needs the extra speed available with a 26x10. Even with a 26x10 at full throttle, the Cub will not look faster than scale due to the size and drag. Of course, you probably won't be tooling around at full throttle all of the time. My favorite props in the 26x10 range are the Menz S and the Bambula.

Since you didn't mention twins, I didn't. I have a Brison 6.4 and like it very well. Both the 5.8 and 6.4 have mechanical spark advance and I have never had any problem with them. Some of the 3D fliers say that they like the mechanical advance better because the advance is more precise for hovering etc. I also have the CH/Syncro-spark on a Sachs 4.2 in my Bücker Jungmeister and it works fine. I'm sure that you can get the electronic advance with the Brison 5.8. It is simply a matter of locking the advance ring in place with a set screw and using a CH Ignition with Syncro-spark.

I guess you noticed on the Fox site that they didn't go to the trouble of showing you a photo of their individual gas engines. Maybe there is a reason that you don't hear much about Fox engines. Could it be marketing and over priced?

Keep us posted on your Cub project.

Ken

The problem with too much advance on the old engines was the person who put the parts together..I have seen some with as much as 45 degrees or more advance..It's just a matter of getting the linkage right, not that sloppy "Rube Goldberg" setup they used...

Big Bird,

Does th 5.8 shake any more than a ZDZ 80. I have the ZDZ 80 and find vibration to be an non issue, was cosidering a 5.8 Brison for my next setup because they run so sweet! But vibration could be a issue.

Ralph, you are right about the advance. Anything done wrong causes problems and I'm sure you have seen a lot of engines timed wrong by people who didn't have a clue. Timing an engine is not rocket science and there is plenty of information out there on how to do it. CH Electronics web site is a good reference. I don't find the throttle coupled spark advances on the Brison engines to be sloppy. The Delrin ring is a very nice fit and the ball joints allow no slop in the linkages.

Flip and Fly I'm sure the Brison 5.8 shakes a bit more than the ZDZ80RV. The 80 is one of the smoothest engines out there in its size class. As I said I use my 5.8 on a Ziroli Corsair which has a very strong frame and I don't notice any unusually high amplitude shaking. If you have ever put your hand on a running plane powered by a Brison 6.4 or a BME 110 Extreme twin, they shake too. I wouldn't be inclined to put a 5.8 in a 24# Edge 540. Any time you take a powerful engine and produce a strong power pulse each revolution you are going to get some shake. I wonder if the in-line twins that alternately fire produce less shake. By the way, what is your new project?

Happy Thanksgiving

Ken

Each time I see one of the "big singles shake" comments I suspect that the writer has not used the ZDZ80 singles.
When these engines are setup acording to spec - and properly adjusted - you can do full run up tests with out the wings on the plane.
I do it all the time with models that are 18 lbs to 23 lbs .
Other hard core twin fans have commented on how smoothly these run.
I also suspect that many other engines (singles) will do the same setup correctly.
I have seen 100 twins which shook much more.
They also vibrated (different problem)
The old inline twins I worked with really sucked - they were the ST 6000's and were , frankly impossible for the "engine impared" modelers to make run correctly.
There are some new inline twins on the market -which from a purely theoretical standpoint ---should---be smoother.
simply because there are two power pulses per prop revolution
this means that th prop should maintain speed better -reducing the reaction that occurs as compared against a engine of same power, firing once each revolution.
( look at a large displacement four stroke single to see how this can get out of hand.)

Big Bird, thanks for the reply, you must have read my mind! I was thinking of scratch building my self a 35% Edge, or Extra for IMAC. My goal is to build a 35%er with a wing area of about 1900 sq in, and then make it light as possible!!!!!!!!!

I scratch built a 35% ( or so) Ultimate that flies on rails (for an Ultimate) its a good 3D plane but not the best for IMAC. Bipes have a tendency to over rotate in maneuvers, and it does have a little pitch roll coupling, however not too bad! Its been a rewarding experience for sure.

For my next design I am going to order a Hangar 9 cowel, and canopy, for the Edge, or Extra, and start with that. The rest I make, my own plans and all. I will also use TNT carbon fiber gear ( I have one on my Midwest Extra and it has been holding up well)

I was looking at the Brison 5.8 because my Brison 2.4 has been so reliable, and good bang for the buck. Now I am thinking of swapping my ZDZ out of my Bipe, and puting in a in-fuse tuned pipe and maybe following the advice of Mr Dick Hanson to squeeze every ounce of power out from that engine. Its also a nice motor for sure, just a little concerned about their durability. Mine has over 10 hours flying on it and turning a biela 26-10 at 6100-6300 depending on the day I tack it and the powers that be! Thats with a Bisson pits muffler and all!

Thanks.............

Big Bird: Appreciate your advice. I have a lot to learn, and I've been modeling since 1937. You are probably quite correct - that the 26 x 10 would be a better prop selection for the big Cub. I am amazed that the ZDZ80 can do the same job as a normal 5.8 (95 cc) engine. I wouldn't have believed it possible, since it has 15% less displacement than the 5.8 engine, but everybody that owns one only has good things to say about it. That seems to be the least expensive route to get the job done in a satisfactory manner. I have shyed away from the twins because of the cost.

O.K. Here's an update on the Cub. It's completely finished - just waiting for an engine. It is 40% scale, 14.5 ft span, and will weigh in at close to 40 lbs. It is covered with Ceconite, doped, and painted with latex paint. If it flies as good as expected, I will make plans available along with a complete building instruction manual. See photos below.

Jim, that is one beautiful Cub. I think you will like the 80 in it. I use a Bisson Pitts style muffler with clipped tips and the engine turns a Menz Standard 26x10 prop between 6100 and 6300 depending on the humidity and temperature.

Here are a few shots made at Bomber Field this year of my 1/3 scale 126" wing span Hostetler Super Decathlon. It weighs 32# and is very aerobatic.

Ken

sure some pretty scale stuff -
here is my last scale job-scratchbuilt from my plans

Nice to see what everyone is building, great picks, and work! here's my Ultimate. Span 80" length 82" 25lbs, 2080 sq in, ZDZ 80.

http://www.geocities.com/krcm_home/2...z_ultimate.jpg

If you want to run a bigger prop on the ZDZ-80, go ahead. I ran a Menz-S 27x10 @ 5900 rpm with J&A Pitts muffler. Flew it for a season of IMAC on a H9 Cap - plenty of pull, but a little slower straight and level than a 26x10 prop.

It is always amazing to me when I see some folks brag about how large a prop they can run on their (your favorite here).
I have never seen oversized props increase power or thrust in the air..
(nor cold fusion or a flying cow.)

If the pull on the upline was as good with a 27-10 than a 26-10, that would be good, losing a little speed in the strait and level may not matter so much for IMAC. It could also give a more constant speed in the box and the need for less throttle management in maneuvers.

However for the ultimate power out of hovers, or stop and go flying (3D), or at the other extreme air racing one has to squeeze all one can get for a particular motor, and prop combination. I think it all comes down to what we are attempting to do.

yes -if one is not good at throttle management - then loading on the prop holds down speed et..
but at the expense of increased heat and less power.