Hey guys, I got a brison 3.2 that just doesn't seem to be happy. It's turning a Xoar 21-8 about 7000 is that good or not. Also tried a Meijlick 20-10 got about 7500 on the ground. Not sure what to expect, I'm flying a 19 pound ultimate with it. Any suggestions?

prop for 6500 to 7500 on the ground

8400 21 x 8 bolly
6700-6800 21 x 10 menz
6400 22x 10 menz
7300 21 x 10 mejzlik
6150 rcs
7000 22 x 8 menz
7100 22 x 8 mejzlik
6700 bambula 22 x 8

all on a peacekeeper

on a es pipe

22a 7300
22x 8 xoar 6900
22x 8 mejzlik 7350
22 x 8 xoar 6800
23a 6870

That's a little low for a 21x8. Maybe you are still a little rich or pissibly even lean. You can tell if you're lean if it drops RPM's after 5 or more seconds. If it's rich you will slowly gain RPM's. In either case it will not reach and maintain it's highest possible peak RPM's.

You're under propping the engine for sure. For better performance I'd be looking at a 22-8 Menz, 22-8 NX, or a 22-8 or 10 Mejzlik. All of them put the engine in an excellent torque/rpm band.

Oh, yea, tweak the needles. Your engine will have more than enough oomph to performance fly a 19lb. Ultimate if it has any wing area at all.

NX 22-8 or NX 21-8 should do the job. I flew a Fox 3.2 (same cylinder as a Brison 3.2) with those 2 props on a GP 1/3 scale Pitts for a time. It wasn't unlimited, but it was plenty powerful enough to out of trouble.

(or INTO trouble in my case [sm=lol.gif])

It's been a few years, so I'm pulling these numbers from memory. It turned both props over 7000. I think the 22-8 was about 7100__7200RPM and the 21-8 was around 7600RPM. I liked the 21-8 prop and the higher RPMs. It just felt like it flew that big ole bipe better when it was spinning more RPM's. The 22-8 flew it okay, but the engine felt sluggish on uplines.

Consider I'm flying at almost 6000', so that might have a little to do with me liking the smaller prop and more RPM's.

I have several Brison 3.2's and have found that proping for more than 7000 rpms on the ground gains little or no advantage in the air.
These engines are at their best between 6200 and 7000 rpms . I prefer the NX 22-8 for best overall performance for aerobatics. the 3w 22-8 is also very similar in
performance . For scale flight a 22-10 works well.

Thank you all guys, all this information will help.

What is a NX prop, I believe you about the power band between 6200 and 7000. I relate it to a glow 90 super tiger when I read in an article its best power was 8 or 9 grand and it flew very well with a 15-8 prop. My ultimate has a wing loading of about 24 oz. a sq. foot

NX is an Airwild brand name. They are good props. Prolly like a Xoar. Some say they are made in the same plant but who knows for sure.

I don't know for certain who makes the NX, but it is definately superior to the run of the mill Xoar. I did a side by side performance test with Menz, Xoar, NX, Vess, and TBM. The NX beat them all in climb and hover pull out performace using a Taurus 3.2 in a Wild Hare 28%, v-2 Edge. Ask Altavillan, he was there. Admittedly the Xoar used for that particular test was a 23-8 while all the rest were 22-8, but previous work with a 22" Xoar indicatred that it would not have even come up to the TBM prop in performance, which was pitiful. The test was about performance, not rpm. The Vess seemed to have a lot of rpm but didn't want to do much work. Same thing with the Xoar, although it did make a lot of noise, like the Vess.

The Brison 3.2 is not enough different from the Taurus to matter when it comes to prop performance. Since I have a pair of Brison 3.2's and one Taurus 3.2 I can state that with first hand knowledge of both engines.

Good stuff guys thanks again especially to tired old man

yep i just ordered a NX 22-8, i maiden a friends GP Ultimate this past week end and he had a NX 22-8 on it with a da50 i was really impressed the way it pulled the ultimate around.

I ran my Ultimate with the brison 3.2 yesterday with a 22-6/10 Zinger. Because it was what I had it tacked 6800 on the ground and flew good pulled it around fine. I also cut the tips off the bison wrap around muffler I think this eliminated a little back pressuere. Not much louder if any. Plan to order a NX 22-8

I had two Brison 3.2. I had the best performance in the air when the engine tached 7200-7400 rpm on the ground. The props I used to accomplish this were: BME 22x8, 3W 22x8. Menz 22x8, NX 22x8, Mejlick 22x8. The MSC 22x8 loaded up a bit more @ around 7000 rpm. but pulled like a horse. Good luck.