yard-dart

My Feedback: (35)

I have been pondering over this for several days now, and really haven't been able to totally make up my mind as which one to buy. The engine I decide on will be going in a Pac Aero 1.20 Gee Bee Y. I have heard great things about the Brison, such as reliability, ease of use, and power. I've not heard too much about the Evolution. I do know that it is pretty much the same engine as the MVVS. I have read a couple of posts where users of this engine were pretty well satisfied. What I have questions about is the type of ingition the Evo has. Is it reliable? Where is it located on the engine. From the pics, the timing pick-up is nowhere to be seen. I've read only rave reiews about the C&H Ignition the Brison comes with.

Weight is also a factor. The Evo specs say that it comes in right at 52 .oz, while the Brison specs say that it comes in right at 44 oz. Are they really that far off in weight?

Besides the weight, both engines' specs are pretty close to being the same.

Any info I can be given will definately help with the decision on which one to buy. I've been leaning more towards the Brison, I just don't want to rule out the Evo if it could, in fact, be a better engine.

Thanks,

John

the Wasp

My Feedback: (1)

Gee,,, I just happen to have that plane with a MVVS 35 gasser in it (same motor as the Evo 35), the plane flies just like a heavy 4-Star 60 would feel, nice, smooth and solid in the air,,, I can say that with a 35cc the plane is NOT over powered, although it flies nicely with this motor it's straight up~ full throttle vertical IS limited, yet when flown high this plane/motor setup feel's more comfortable than a smaller 60/90 does, I did find myself flying it higher much more than I would a 70 inch span plane with a 90 motor, so with that said I would say that it's not under powered~ just NOT over powered,,, but if you asked "would I like more pulling power than the 35"~ YES !!

if you want to hover it you better buy a DA 50cc, MVVS 58cc or even a 60cc !!

I don't think it will fly faster with the bigger 40cc motor because of drag (because I don't feel it dives any faster than the 35 can pull it level a full throttle) , but a 40cc should pull it off the ground quicker and give it more straight up vertical,,,

my MVVS 35 will not pull a 20x10 prop like a Brison will, I tuned it for flight at 5400 with a 3W 20x10 and the motor would flame-out when going full throttle vertical (I think it over heated), yet on the ground it would spin the 3W 20x10 at 5900,,,

now, on 89 octane with a Zinger 20x8 pro I got 7590 (I'm sure I can get over 7600 on Sunco 94 octane), I tuned it for flight at 7400, my 7590 number is as good and better than some guys are getting with their Brison 40cc,,,

the Gee Bee Y landing struts at $7 each are junk, pick up the phone now and call Robart for struts, the part number is "# GBY" ($165),,,

and because of the added weight glue the wings together, and add some fiberglass around the outside where the wings come together (for good luck)

good luck, let us know what you do..
Jim

Tired Old Man

My Feedback: (1)

Couple of things to ponder here. One is that lighter flys better, no matter what anybody may say. If you can save 8 ounces right off the bat and have a larger displacement engine that issue should be pretty much settled. As for the weight statements, Brison has been making the 2.4 for a very long time and the listed weight is well documented.

As for hovering a GeeBee, well... they were never designed for that so you may be getting into some control authority issues when you fall out of one. I certainly hope you have enough elevator and altitude to save your bacon.

Don M.

My Feedback: (5)

I have a Brison 2.4 and a MVVS 26cc and both ignition systems are A - 1, I assume the 35cc is the same ignition as my 26cc. My Brison WILL NOT turn a 20 - 10 prop ( 6300 rpm ), at least not the one I tried, it heats up and generally acts terrible, it is however very happy on an 18 - 10, about 8000 rpm.

As far as weights go I would have to know what was included, my brison absolutely bare weighs 40 ozs. but with everything needed to fly ( less prop ) it weighs 62 ozs.

yard-dart

My Feedback: (35)

I'm pretty much on the same page as the surfer dude. The Gee Bee Y is definately not a plane that someone should try to hang on the prop, 3D isn't my cup of tea anyway. I agree with the weight issue also. Lighter is pretty much always better, along with getting more cc's in the mix.

I'm gonna give this thread just a little more time, just to see what other kinds of responses I get. As of right now, I'm leaning more and more towards the Brison.

Also, is it because of the Nikasil liner in the Brison that they reccommend starting out with Synthetic oil. Simply by accident, I started out my first gasser (Zenoah G23) on Amsoil. After some of my buddies found out what I had done, they were worried that the engine wouldn't break in properly. They told me I should have started out with a basic petroleum based two stroke oil. Well, my engine ran superbly from the day I started it until a few years later when I sold it, and I'm quite sure it's running that way today. So, my big question is, will starting out with Synthetic (Amsoil) hinder the break-in process of my engine, or not? (it didn't in my Zenoah)

Feedback please, and keep the comments on the engine comparison coming.

Thanks,

John

Flip and Fly

Do a search on the Brison and you will find many happy people! I have one, turns a 20-8 Bolly Wood at 7300, sea level, summer weather! In the cool spring autumn weather it will only turn 7100 rpm so don't put all your faith in peoples prop numbers

Also will turn a Master Airscrew 20-8 at 7600 rpm in the summer.

3D with a Gee Bee[X(] They do knife edge well

My Motor has been flawless, great running, and will 3D my 14lbs extra.

Don M.

My Feedback: (5)

Synthetic vs. Perto oil is an age old question and you'll get as many answers as there are engines out there. Along with my R/C addiction I also am addicted to snowmobiles. Back in 1997 I bought a new snowmobile with a 500cc twin in it before I ever started it for the first time I drained the injection oil from the reserve tank and replaced it with syn. oil. I thought I was doing the right thing but everyone told me I should have broken it in on perto oil, well I didn't and 10 years and 10,000 miles later that engine is working A-1, never had a hiccup, go figure

yard-dart

My Feedback: (35)

Yeah, I think I'm gonna just go with the Brison. The Evo may turn out a great engine, but it just doesn't have enough of a history behind it right now to win me over. Brison seems to have a great background, all around.

As for Syn. vs Petro oil, who knows. I guess the bottom line is to simply make sure the engine is getting enough lube. What makes me lean more toward Syn. is the cleanliness of it. It doesn't leave a lot of residue on the airframe, and as long as you mix it right, it provides adiquate protection/lube.

Tired Old Man

My Feedback: (1)

I posted this in another thread here in the gas engine forum. Gary suggests an 80-1 mix of synthetic for ALL of his engines from day one. I hope the copy below eases your mind a bit.

Happy New Year

Pat

In response to your query about the ratio, I have a pair of Brison 3.2's and a 6.4. That equates to a couple of dollars or so that I don't want to have to spend again. One of the 3.2's has been running Motul 800 or Redline racing oil for the last three and a half years. The other has been running Redline for the last year. The 6.4 has been running Redline for the last year. All at 80-1. One 3.2 and the 6.4 have been run at 80-1 from the first firing. All look very good. The older 3.2 was sent back to Brison in June of this year due to crash damage. The cylinder and piston looked almost new after many hundreds of flights.

In the beginning with the older 3.2 I was pretty leery about what seemed to be a lean oil mix and ran it with a 40 or 50-1 mix initially. The plugs seemed to foul more often than I thought they should regardless of the mixture setting. Numerous conversations with Gary Allison, AKA Mr. Brison, convinced me to go with the 80-1 mix and I have not been the least bit sorry. It's also what he recommends in the owners manual. You can take it from there.

Flip and Fly

I have been running my ZDZ 80 with Motul 800 for the last 3 years at 40-1. My ZDZ had a crank failure, not oil related, I took it apart and the piston and all looked good. A little carbon is all. Rings fine.

Now get this, I do the same mix with the Brison, all fine for a while then it starts getting harder to start. Hmmmm. So I play with the needles, lean the low end some still hard to start. Hmmm.
People here at RCU are having problems getting the Brison 2.4 to start. I pull the plug and its getting fowled. So I changed my mix to 60-1 and no more fowled plugs. Starts up fine now.

Silversurfer you are right, I still don't know why but the Brison likes it a little more lean on the oil mix.

Not trying to start a mixing war! Do what ya want, but I still can't figure why this is with the Brison.

Still happy with my little Brison

Bob Pastorello

My Feedback: (198)

Another "different" Brison story.... I have a nearly-new (less than 1 gallon) 2.4. Runs like a HOSS. Started with Redline at 80:1 per the guys (Gary and his Dad) at Brison.... ran okay, but seemed to need the needles leaner than I thought was good to have a clean transition.

So ... new and different airplane install (my Goldberg Yak) and the jug of gas I had was my Stihl 50:1 that I'm using for break in on the Taurus T-52 (THAT is an OUTSTANDING engine). I know ya'll are jumpin' through your instruction manuals - but - it was what I had.

Fired that mutha up, tweaked the low end a bit.... boy. It **LIKES** this oil ratio, at least right now. Maybe it's too tight for the synthetic Redline, I don't know enough about that. But I do know that I have almost a half gallon on the Stihl mix, and it is running better and better. Plug looks GREAT.... piston and sleeve fine, too.

Will it blow up next week? Who knows? After it gets some time on it, I may go back to the Redline, but at this point, it just doesn't seem like this particular motor likes the synthetic.

Comments?? Ideas??
(BTW - I have owned a few MVVS gassers - not the new ones packaged as Evolution... they ain't got what it takes in the 35 or the 25, either one.)

Tired Old Man

My Feedback: (1)

Whatever you use, the plug will tell the story. If it loads up sooner than you think it should, go back to the other mix and see what happens. Unless you exceed about 13,000rpm, the engine should last a long, long time.

Pat

go vertical

My Feedback: (1)

In my opinion the brison 2.4 is at the top of the class in engines under 50cc i have 3 brison's all have been run on synthetic oil from the start at 50to1 no problems with plugs or weare on the engine my 6.4 is my oldest at 7 years and is still runing strong on the second set of plugs

yard-dart

My Feedback: (35)

Well, my engine just came in (Brison 2.4). I have to admit, I'm happier than a queer with a bag full of peckers! I'm glad I went with the Brison, instead of the Evolution. From the previous responses, the Evo would never perform as well.

Thanks for the support fellas,

John

Hans Meij

John, you will never know, because there are no direct comparisons. Have a MVVS35 myself and am very happy with it. On the pipe it performs very well, better than a ZDZ40 on same prop pipe and plane.
Also can compare the MVVS45 with the Revolution 52 with same prop and exhaust system because have these engines too. The MVVS45 is better in that equasion.

the Wasp

My Feedback: (1)

well as I have said, my MVVS 35 (inverted muffler) turn's a Zinger 20x8 pro a little higher than some guys have posted for their Brison 2.4, but my MVVS just will not pull a 20x10 like the Brison will, this tells us that the Brison make it's power a little lower on it's power band than the MVVS does,,, I'm betting a 21x 8 or 22x 8 will work nicely on the Brison..

by the way, I'm done with Zinger, for only $3 more I can buy a 3W prop, with a much nicer finish the 3W is just about balanced right out of it's package...

Jim

go vertical

My Feedback: (1)

I have noticed that almost every one who gives rpm figures for eather mvvs or evo engines use tuned pipes no pipes on the brison does anyone make tuned pipes for the brison if so what rpm's with a pipe

Bob Pastorello

My Feedback: (198)

I have to say that although the MVVS and ZDZ's are reputed to produce LOTS of power, it is ALWAYS requiring a pretty specialized "tuned" pipe or canister system.

I think the fair comparison for a buyer is to consider the motor's performance with the type of muffler he's planning on using. Otherwise, it's apples to oranges, and not fair to anyone.

Compare motors with wrap-around Pitts mufflers, and I think one will learn that the MVVS/Evos and ZDZ's just ain't cuttin' it.

(And YES - I **have** owned both brands in the past.)

go vertical

My Feedback: (1)

aerobob

I am glad someone else feels the same as i do if you put so much stock in rpm numbers use the same prop &sane type exaust system otherwise the test is not accurat

yard-dart

My Feedback: (35)

I finally got a cable for my camere, so, I just had to post some pics. Hope you all like 'em.

Sorry fellas, can't get 'em to upload. I'll try again later.