I don't tune with the tach --I match props to the task with the tach.
The wierd part is that the shape of the blade has little to do with how hard it pulls.
It is how much it unloads with speed .
Good 3D props are pretty much at upper end of effective rpm power band- on the ground. I get way less than a thou unload on best 3D props and closer to or more than a thou on best IMAC-
Obviously the best IMAC are loading more on the ground- so unload more in the air - it takes a little putzing around but the numbers seem to match which type performance is desired .

tuning -always by ear - the needles - -yep-- just an initial referrence
I am always amazed a guys who get a new engine and it is perfectly set from the factory - (how did they do that?)

hi all, been reading all your posts on the da50 and its varied rpm range.

my da50 swings a menz 22x10 at around 6100 at mo which i think is low as it wont haul my fatass world models katana up those verts for too long!!!!!

just off out to play with it in the yard with my tacho. will be back shortly with the results!!!!


paully B

right all!!!!

just ran it with the exhaust on and got 6100 max. took the exhaust and got 6300-6400 max!!!!

ehaust is a wraparound style pitts twin pipe unit.

following a preivious post here, i chopped off the pinched n tips of the exhaust stacks.

Refitted it and ran it........6300 no probs


blimey!!!

Yep, them swaged tips put an amazing amount of constriction on the exhaust.

I might suggest you change to a 22x8 prop... you gain several hundred more RPM and should get you upwards of 7000 rpm...

I think the engine does best when operating in the 6700-7000+ range...

I broke my DA-50 in with a NX 22x8 and liked it so much I continue using it, get 7040RPM with that prop using Amsoil 100:1 and standard DA-50 muffler

I know we fly upside down here but with a Bolly 22 - 8 wood I tach at 6900 ( sea level).

Maudib
(mouse of the desert?)

I don't believe it. At least three people have listened to us and have reaped the benefit of better performance. We just need to get the third to change to the 22-8 and it will be success at last.

Anyone has RPM numbers with canister?

hi there, took your advice again and opted for a 22x8 menz to see what that will do.


will let you know in a few days.


paul

It's gonna Shwing! that prop... like an engine on Viagra... [X(]

i have just been advise to put a mejzlik 23x8 on it. thing is, they arent cheap!!!!!

waddya think???

In the long run it's good to ahve a few props on hand, because each will feel different on a different airframe with the same engine.

However, based on your numbers wiht the 22x10... I'd stick with the 22x8.. ti is far and away the most popular prop size out there...

If you can get MSC, they are nice, powerful and a few $$$ less than Mejzlik...

A Mejzlik 23-8 actually measures between 22-3/8" to 22-5/8" for those interested. I believe Menz measures in a similar manner.

Silversurfer
tks for the measurements on that 23 x 8 i never did measure mine back in the day when i tried one. Had to sell it, it was just to much of a load on my airframe.

where is a good place to buy msc props??? i have never heard of them here in theuk.

i dont mind ordering one in from abroad.

paul

http://www.mscprops.com/

6400 RPm on Mejzlick 23x8 here witjh Slimline pitt muffler

6300 on Brison 3.2 with J & H peacekeeper poweband is 6500-7500

23 and 24" props are just a little too much for 50cc motors. Loads them down a lot unless you have really slim pitches. You may feel that you're getting a lot of "pull" with one, but that engine will be working a lot harder and hotter than it should.

MSC props are available direct at www.mscprops.com out of Canada, BME Aircraft, and Desert Aircraft.

Silversurfer,

Your's must be short..............I just got done measuring mine...........Uhhhhhhhhh Mejzlik 23 x 8 prop that is. It's a full 23 inch long.

I agree with Silversurfer. I used to run a mejzlik 23*8 on pitts muffler at 6400 rpm. Not bad for IMAC but after using a Bolly 23*8 wood I beleive the weight of the mejlik was a bit heavy for the engine trying to throttle up (especially for 3d). The bolly wood 23*8 used to get 6600 on a pitts muffler. I have just changed to a canister and a 22*8 Bolly wood and get 6900rpm. Throttle response is excellent especially for 3d and in the long uplines the recovery from snaps,ect is quicker. These figures are all at sealevel.

Hey guys,

I just finished putting together a WM 27% ultimate. It has a DA50 on the nose and I fired it up for the first time today. I am running a bolly wood 22x8 and a slimline pitts muffler. The fuel I'm using is BP ultimate(98 octane) mixed with castrol active 2T mineral oil mixed a 32:1. I set the needles as per the manual and started it up. Got 6600rpm at those settings. I then leaned the high end 1/4 of a turn and now its pulling 6800rpm. The tranistion is excellent and idle is good. It is still a little rich but that's ok for now. I'm yet to fly the ultimate so I'm not sure what the flight performance will be like at 16.7lbs (7.6kg) Hopefully I will get it in the air this weekend. But I'm pretty sure this engine will be a winner. I've also got a 23x8 bolly wood to try after break-in.....

i thought that DA 50 was suppose to be a powerhouse[8D]

Watch it Krayzc, pretty soon they might figure out that the Brisons were a lot better value for the money Nogyro, mine's long enough to keep me happy

Rusty, your Ultimate is going to fly just great!! You might want to put a tether on it to keep it in sight.

"my brison will swing a menz 22 x 8 at 7200 very strong engine for the price. i can swing a 23 x 8 mejzlik at 6300 to much load for the motor on a J & A peacekeeper. Power band is better in the 6500-7500 range. "

Silversurfer
u r so right this is my orginal post back on page one above. Man those DA should just go fly and leave the numbers game along.

I guess 50cc is 50 cc if you have decent porting and exhaust. And just think a Brison is 3.25 lbs.